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Diffstat (limited to 'freebsd/contrib/libpcap/gencode.c')
| -rw-r--r-- | freebsd/contrib/libpcap/gencode.c | 8493 |
1 files changed, 8493 insertions, 0 deletions
diff --git a/freebsd/contrib/libpcap/gencode.c b/freebsd/contrib/libpcap/gencode.c new file mode 100644 index 00000000..8bee7904 --- /dev/null +++ b/freebsd/contrib/libpcap/gencode.c @@ -0,0 +1,8493 @@ +#include <machine/rtems-bsd-user-space.h> + +/*#define CHASE_CHAIN*/ +/* + * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that: (1) source code distributions + * retain the above copyright notice and this paragraph in its entirety, (2) + * distributions including binary code include the above copyright notice and + * this paragraph in its entirety in the documentation or other materials + * provided with the distribution, and (3) all advertising materials mentioning + * features or use of this software display the following acknowledgement: + * ``This product includes software developed by the University of California, + * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of + * the University nor the names of its contributors may be used to endorse + * or promote products derived from this software without specific prior + * written permission. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * + * $FreeBSD$ + */ +#ifndef lint +static const char rcsid[] _U_ = + "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.309 2008-12-23 20:13:29 guy Exp $ (LBL)"; +#endif + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#ifdef WIN32 +#include <pcap-stdinc.h> +#else /* WIN32 */ +#if HAVE_INTTYPES_H +#include <inttypes.h> +#elif HAVE_STDINT_H +#include <stdint.h> +#endif +#ifdef HAVE_SYS_BITYPES_H +#include <sys/bitypes.h> +#endif +#include <rtems/bsd/sys/types.h> +#include <sys/socket.h> +#endif /* WIN32 */ + +/* + * XXX - why was this included even on UNIX? + */ +#ifdef __MINGW32__ +#include "ip6_misc.h" +#endif + +#ifndef WIN32 + +#ifdef __NetBSD__ +#include <rtems/bsd/sys/param.h> +#endif + +#include <netinet/in.h> +#include <arpa/inet.h> + +#endif /* WIN32 */ + +#include <stdlib.h> +#include <string.h> +#include <memory.h> +#include <setjmp.h> +#include <stdarg.h> + +#ifdef MSDOS +#include "pcap-dos.h" +#endif + +#include "pcap-int.h" + +#include "ethertype.h" +#include "nlpid.h" +#include "llc.h" +#include "gencode.h" +#include "ieee80211.h" +#include "atmuni31.h" +#include "sunatmpos.h" +#include "ppp.h" +#include "pcap/sll.h" +#include "pcap/ipnet.h" +#include "arcnet.h" +#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER) +#include <linux/types.h> +#include <linux/if_packet.h> +#include <linux/filter.h> +#endif +#ifdef HAVE_NET_PFVAR_H +#include <sys/socket.h> +#include <net/if.h> +#include <net/pfvar.h> +#include <net/if_pflog.h> +#endif +#ifndef offsetof +#define offsetof(s, e) ((size_t)&((s *)0)->e) +#endif +#ifdef INET6 +#ifndef WIN32 +#include <netdb.h> /* for "struct addrinfo" */ +#endif /* WIN32 */ +#endif /*INET6*/ +#include <pcap/namedb.h> + +#define ETHERMTU 1500 + +#ifndef IPPROTO_HOPOPTS +#define IPPROTO_HOPOPTS 0 +#endif +#ifndef IPPROTO_ROUTING +#define IPPROTO_ROUTING 43 +#endif +#ifndef IPPROTO_FRAGMENT +#define IPPROTO_FRAGMENT 44 +#endif +#ifndef IPPROTO_DSTOPTS +#define IPPROTO_DSTOPTS 60 +#endif +#ifndef IPPROTO_SCTP +#define IPPROTO_SCTP 132 +#endif + +#ifdef HAVE_OS_PROTO_H +#include "os-proto.h" +#endif + +#define JMP(c) ((c)|BPF_JMP|BPF_K) + +/* Locals */ +static jmp_buf top_ctx; +static pcap_t *bpf_pcap; + +/* Hack for updating VLAN, MPLS, and PPPoE offsets. */ +#ifdef WIN32 +static u_int orig_linktype = (u_int)-1, orig_nl = (u_int)-1, label_stack_depth = (u_int)-1; +#else +static u_int orig_linktype = -1U, orig_nl = -1U, label_stack_depth = -1U; +#endif + +/* XXX */ +#ifdef PCAP_FDDIPAD +static int pcap_fddipad; +#endif + +/* VARARGS */ +void +bpf_error(const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + if (bpf_pcap != NULL) + (void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE, + fmt, ap); + va_end(ap); + longjmp(top_ctx, 1); + /* NOTREACHED */ +} + +static void init_linktype(pcap_t *); + +static void init_regs(void); +static int alloc_reg(void); +static void free_reg(int); + +static struct block *root; + +/* + * Value passed to gen_load_a() to indicate what the offset argument + * is relative to. + */ +enum e_offrel { + OR_PACKET, /* relative to the beginning of the packet */ + OR_LINK, /* relative to the beginning of the link-layer header */ + OR_MACPL, /* relative to the end of the MAC-layer header */ + OR_NET, /* relative to the network-layer header */ + OR_NET_NOSNAP, /* relative to the network-layer header, with no SNAP header at the link layer */ + OR_TRAN_IPV4, /* relative to the transport-layer header, with IPv4 network layer */ + OR_TRAN_IPV6 /* relative to the transport-layer header, with IPv6 network layer */ +}; + +#ifdef INET6 +/* + * As errors are handled by a longjmp, anything allocated must be freed + * in the longjmp handler, so it must be reachable from that handler. + * One thing that's allocated is the result of pcap_nametoaddrinfo(); + * it must be freed with freeaddrinfo(). This variable points to any + * addrinfo structure that would need to be freed. + */ +static struct addrinfo *ai; +#endif + +/* + * We divy out chunks of memory rather than call malloc each time so + * we don't have to worry about leaking memory. It's probably + * not a big deal if all this memory was wasted but if this ever + * goes into a library that would probably not be a good idea. + * + * XXX - this *is* in a library.... + */ +#define NCHUNKS 16 +#define CHUNK0SIZE 1024 +struct chunk { + u_int n_left; + void *m; +}; + +static struct chunk chunks[NCHUNKS]; +static int cur_chunk; + +static void *newchunk(u_int); +static void freechunks(void); +static inline struct block *new_block(int); +static inline struct slist *new_stmt(int); +static struct block *gen_retblk(int); +static inline void syntax(void); + +static void backpatch(struct block *, struct block *); +static void merge(struct block *, struct block *); +static struct block *gen_cmp(enum e_offrel, u_int, u_int, bpf_int32); +static struct block *gen_cmp_gt(enum e_offrel, u_int, u_int, bpf_int32); +static struct block *gen_cmp_ge(enum e_offrel, u_int, u_int, bpf_int32); +static struct block *gen_cmp_lt(enum e_offrel, u_int, u_int, bpf_int32); +static struct block *gen_cmp_le(enum e_offrel, u_int, u_int, bpf_int32); +static struct block *gen_mcmp(enum e_offrel, u_int, u_int, bpf_int32, + bpf_u_int32); +static struct block *gen_bcmp(enum e_offrel, u_int, u_int, const u_char *); +static struct block *gen_ncmp(enum e_offrel, bpf_u_int32, bpf_u_int32, + bpf_u_int32, bpf_u_int32, int, bpf_int32); +static struct slist *gen_load_llrel(u_int, u_int); +static struct slist *gen_load_macplrel(u_int, u_int); +static struct slist *gen_load_a(enum e_offrel, u_int, u_int); +static struct slist *gen_loadx_iphdrlen(void); +static struct block *gen_uncond(int); +static inline struct block *gen_true(void); +static inline struct block *gen_false(void); +static struct block *gen_ether_linktype(int); +static struct block *gen_ipnet_linktype(int); +static struct block *gen_linux_sll_linktype(int); +static struct slist *gen_load_prism_llprefixlen(void); +static struct slist *gen_load_avs_llprefixlen(void); +static struct slist *gen_load_radiotap_llprefixlen(void); +static struct slist *gen_load_ppi_llprefixlen(void); +static void insert_compute_vloffsets(struct block *); +static struct slist *gen_llprefixlen(void); +static struct slist *gen_off_macpl(void); +static int ethertype_to_ppptype(int); +static struct block *gen_linktype(int); +static struct block *gen_snap(bpf_u_int32, bpf_u_int32); +static struct block *gen_llc_linktype(int); +static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int); +#ifdef INET6 +static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int); +#endif +static struct block *gen_ahostop(const u_char *, int); +static struct block *gen_ehostop(const u_char *, int); +static struct block *gen_fhostop(const u_char *, int); +static struct block *gen_thostop(const u_char *, int); +static struct block *gen_wlanhostop(const u_char *, int); +static struct block *gen_ipfchostop(const u_char *, int); +static struct block *gen_dnhostop(bpf_u_int32, int); +static struct block *gen_mpls_linktype(int); +static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int, int); +#ifdef INET6 +static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int, int); +#endif +#ifndef INET6 +static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int); +#endif +static struct block *gen_ipfrag(void); +static struct block *gen_portatom(int, bpf_int32); +static struct block *gen_portrangeatom(int, bpf_int32, bpf_int32); +static struct block *gen_portatom6(int, bpf_int32); +static struct block *gen_portrangeatom6(int, bpf_int32, bpf_int32); +struct block *gen_portop(int, int, int); +static struct block *gen_port(int, int, int); +struct block *gen_portrangeop(int, int, int, int); +static struct block *gen_portrange(int, int, int, int); +struct block *gen_portop6(int, int, int); +static struct block *gen_port6(int, int, int); +struct block *gen_portrangeop6(int, int, int, int); +static struct block *gen_portrange6(int, int, int, int); +static int lookup_proto(const char *, int); +static struct block *gen_protochain(int, int, int); +static struct block *gen_proto(int, int, int); +static struct slist *xfer_to_x(struct arth *); +static struct slist *xfer_to_a(struct arth *); +static struct block *gen_mac_multicast(int); +static struct block *gen_len(int, int); +static struct block *gen_check_802_11_data_frame(void); + +static struct block *gen_ppi_dlt_check(void); +static struct block *gen_msg_abbrev(int type); + +static void * +newchunk(n) + u_int n; +{ + struct chunk *cp; + int k; + size_t size; + +#ifndef __NetBSD__ + /* XXX Round up to nearest long. */ + n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1); +#else + /* XXX Round up to structure boundary. */ + n = ALIGN(n); +#endif + + cp = &chunks[cur_chunk]; + if (n > cp->n_left) { + ++cp, k = ++cur_chunk; + if (k >= NCHUNKS) + bpf_error("out of memory"); + size = CHUNK0SIZE << k; + cp->m = (void *)malloc(size); + if (cp->m == NULL) + bpf_error("out of memory"); + memset((char *)cp->m, 0, size); + cp->n_left = size; + if (n > size) + bpf_error("out of memory"); + } + cp->n_left -= n; + return (void *)((char *)cp->m + cp->n_left); +} + +static void +freechunks() +{ + int i; + + cur_chunk = 0; + for (i = 0; i < NCHUNKS; ++i) + if (chunks[i].m != NULL) { + free(chunks[i].m); + chunks[i].m = NULL; + } +} + +/* + * A strdup whose allocations are freed after code generation is over. + */ +char * +sdup(s) + register const char *s; +{ + int n = strlen(s) + 1; + char *cp = newchunk(n); + + strlcpy(cp, s, n); + return (cp); +} + +static inline struct block * +new_block(code) + int code; +{ + struct block *p; + + p = (struct block *)newchunk(sizeof(*p)); + p->s.code = code; + p->head = p; + + return p; +} + +static inline struct slist * +new_stmt(code) + int code; +{ + struct slist *p; + + p = (struct slist *)newchunk(sizeof(*p)); + p->s.code = code; + + return p; +} + +static struct block * +gen_retblk(v) + int v; +{ + struct block *b = new_block(BPF_RET|BPF_K); + + b->s.k = v; + return b; +} + +static inline void +syntax() +{ + bpf_error("syntax error in filter expression"); +} + +static bpf_u_int32 netmask; +static int snaplen; +int no_optimize; +#ifdef WIN32 +static int +pcap_compile_unsafe(pcap_t *p, struct bpf_program *program, + const char *buf, int optimize, bpf_u_int32 mask); + +int +pcap_compile(pcap_t *p, struct bpf_program *program, + const char *buf, int optimize, bpf_u_int32 mask) +{ + int result; + + EnterCriticalSection(&g_PcapCompileCriticalSection); + + result = pcap_compile_unsafe(p, program, buf, optimize, mask); + + LeaveCriticalSection(&g_PcapCompileCriticalSection); + + return result; +} + +static int +pcap_compile_unsafe(pcap_t *p, struct bpf_program *program, + const char *buf, int optimize, bpf_u_int32 mask) +#else /* WIN32 */ +int +pcap_compile(pcap_t *p, struct bpf_program *program, + const char *buf, int optimize, bpf_u_int32 mask) +#endif /* WIN32 */ +{ +#if __rtems__ + int n_errors; +#else + extern int n_errors; +#endif + const char * volatile xbuf = buf; + u_int len; + + /* + * If this pcap_t hasn't been activated, it doesn't have a + * link-layer type, so we can't use it. + */ + if (!p->activated) { + snprintf(p->errbuf, PCAP_ERRBUF_SIZE, + "not-yet-activated pcap_t passed to pcap_compile"); + return (-1); + } + no_optimize = 0; + n_errors = 0; + root = NULL; + bpf_pcap = p; + init_regs(); + if (setjmp(top_ctx)) { +#ifdef INET6 + if (ai != NULL) { + freeaddrinfo(ai); + ai = NULL; + } +#endif + lex_cleanup(); + freechunks(); + return (-1); + } + + netmask = mask; + + snaplen = pcap_snapshot(p); + if (snaplen == 0) { + snprintf(p->errbuf, PCAP_ERRBUF_SIZE, + "snaplen of 0 rejects all packets"); + return -1; + } + + lex_init(xbuf ? xbuf : ""); + init_linktype(p); + (void)pcap_parse(); + + if (n_errors) + syntax(); + + if (root == NULL) + root = gen_retblk(snaplen); + + if (optimize && !no_optimize) { + bpf_optimize(&root); + if (root == NULL || + (root->s.code == (BPF_RET|BPF_K) && root->s.k == 0)) + bpf_error("expression rejects all packets"); + } + program->bf_insns = icode_to_fcode(root, &len); + program->bf_len = len; + + lex_cleanup(); + freechunks(); + return (0); +} + +/* + * entry point for using the compiler with no pcap open + * pass in all the stuff that is needed explicitly instead. + */ +int +pcap_compile_nopcap(int snaplen_arg, int linktype_arg, + struct bpf_program *program, + const char *buf, int optimize, bpf_u_int32 mask) +{ + pcap_t *p; + int ret; + + p = pcap_open_dead(linktype_arg, snaplen_arg); + if (p == NULL) + return (-1); + ret = pcap_compile(p, program, buf, optimize, mask); + pcap_close(p); + return (ret); +} + +/* + * Clean up a "struct bpf_program" by freeing all the memory allocated + * in it. + */ +void +pcap_freecode(struct bpf_program *program) +{ + program->bf_len = 0; + if (program->bf_insns != NULL) { + free((char *)program->bf_insns); + program->bf_insns = NULL; + } +} + +/* + * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates + * which of the jt and jf fields has been resolved and which is a pointer + * back to another unresolved block (or nil). At least one of the fields + * in each block is already resolved. + */ +static void +backpatch(list, target) + struct block *list, *target; +{ + struct block *next; + + while (list) { + if (!list->sense) { + next = JT(list); + JT(list) = target; + } else { + next = JF(list); + JF(list) = target; + } + list = next; + } +} + +/* + * Merge the lists in b0 and b1, using the 'sense' field to indicate + * which of jt and jf is the link. + */ +static void +merge(b0, b1) + struct block *b0, *b1; +{ + register struct block **p = &b0; + + /* Find end of list. */ + while (*p) + p = !((*p)->sense) ? &JT(*p) : &JF(*p); + + /* Concatenate the lists. */ + *p = b1; +} + +void +finish_parse(p) + struct block *p; +{ + struct block *ppi_dlt_check; + + /* + * Insert before the statements of the first (root) block any + * statements needed to load the lengths of any variable-length + * headers into registers. + * + * XXX - a fancier strategy would be to insert those before the + * statements of all blocks that use those lengths and that + * have no predecessors that use them, so that we only compute + * the lengths if we need them. There might be even better + * approaches than that. + * + * However, those strategies would be more complicated, and + * as we don't generate code to compute a length if the + * program has no tests that use the length, and as most + * tests will probably use those lengths, we would just + * postpone computing the lengths so that it's not done + * for tests that fail early, and it's not clear that's + * worth the effort. + */ + insert_compute_vloffsets(p->head); + + /* + * For DLT_PPI captures, generate a check of the per-packet + * DLT value to make sure it's DLT_IEEE802_11. + */ + ppi_dlt_check = gen_ppi_dlt_check(); + if (ppi_dlt_check != NULL) + gen_and(ppi_dlt_check, p); + + backpatch(p, gen_retblk(snaplen)); + p->sense = !p->sense; + backpatch(p, gen_retblk(0)); + root = p->head; +} + +void +gen_and(b0, b1) + struct block *b0, *b1; +{ + backpatch(b0, b1->head); + b0->sense = !b0->sense; + b1->sense = !b1->sense; + merge(b1, b0); + b1->sense = !b1->sense; + b1->head = b0->head; +} + +void +gen_or(b0, b1) + struct block *b0, *b1; +{ + b0->sense = !b0->sense; + backpatch(b0, b1->head); + b0->sense = !b0->sense; + merge(b1, b0); + b1->head = b0->head; +} + +void +gen_not(b) + struct block *b; +{ + b->sense = !b->sense; +} + +static struct block * +gen_cmp(offrel, offset, size, v) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; +{ + return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v); +} + +static struct block * +gen_cmp_gt(offrel, offset, size, v) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; +{ + return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 0, v); +} + +static struct block * +gen_cmp_ge(offrel, offset, size, v) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; +{ + return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 0, v); +} + +static struct block * +gen_cmp_lt(offrel, offset, size, v) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; +{ + return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 1, v); +} + +static struct block * +gen_cmp_le(offrel, offset, size, v) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; +{ + return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 1, v); +} + +static struct block * +gen_mcmp(offrel, offset, size, v, mask) + enum e_offrel offrel; + u_int offset, size; + bpf_int32 v; + bpf_u_int32 mask; +{ + return gen_ncmp(offrel, offset, size, mask, BPF_JEQ, 0, v); +} + +static struct block * +gen_bcmp(offrel, offset, size, v) + enum e_offrel offrel; + register u_int offset, size; + register const u_char *v; +{ + register struct block *b, *tmp; + + b = NULL; + while (size >= 4) { + register const u_char *p = &v[size - 4]; + bpf_int32 w = ((bpf_int32)p[0] << 24) | + ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3]; + + tmp = gen_cmp(offrel, offset + size - 4, BPF_W, w); + if (b != NULL) + gen_and(b, tmp); + b = tmp; + size -= 4; + } + while (size >= 2) { + register const u_char *p = &v[size - 2]; + bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1]; + + tmp = gen_cmp(offrel, offset + size - 2, BPF_H, w); + if (b != NULL) + gen_and(b, tmp); + b = tmp; + size -= 2; + } + if (size > 0) { + tmp = gen_cmp(offrel, offset, BPF_B, (bpf_int32)v[0]); + if (b != NULL) + gen_and(b, tmp); + b = tmp; + } + return b; +} + +/* + * AND the field of size "size" at offset "offset" relative to the header + * specified by "offrel" with "mask", and compare it with the value "v" + * with the test specified by "jtype"; if "reverse" is true, the test + * should test the opposite of "jtype". + */ +static struct block * +gen_ncmp(offrel, offset, size, mask, jtype, reverse, v) + enum e_offrel offrel; + bpf_int32 v; + bpf_u_int32 offset, size, mask, jtype; + int reverse; +{ + struct slist *s, *s2; + struct block *b; + + s = gen_load_a(offrel, offset, size); + + if (mask != 0xffffffff) { + s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K); + s2->s.k = mask; + sappend(s, s2); + } + + b = new_block(JMP(jtype)); + b->stmts = s; + b->s.k = v; + if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE)) + gen_not(b); + return b; +} + +/* + * Various code constructs need to know the layout of the data link + * layer. These variables give the necessary offsets from the beginning + * of the packet data. + */ + +/* + * This is the offset of the beginning of the link-layer header from + * the beginning of the raw packet data. + * + * It's usually 0, except for 802.11 with a fixed-length radio header. + * (For 802.11 with a variable-length radio header, we have to generate + * code to compute that offset; off_ll is 0 in that case.) + */ +static u_int off_ll; + +/* + * If there's a variable-length header preceding the link-layer header, + * "reg_off_ll" is the register number for a register containing the + * length of that header, and therefore the offset of the link-layer + * header from the beginning of the raw packet data. Otherwise, + * "reg_off_ll" is -1. + */ +static int reg_off_ll; + +/* + * This is the offset of the beginning of the MAC-layer header from + * the beginning of the link-layer header. + * It's usually 0, except for ATM LANE, where it's the offset, relative + * to the beginning of the raw packet data, of the Ethernet header, and + * for Ethernet with various additional information. + */ +static u_int off_mac; + +/* + * This is the offset of the beginning of the MAC-layer payload, + * from the beginning of the raw packet data. + * + * I.e., it's the sum of the length of the link-layer header (without, + * for example, any 802.2 LLC header, so it's the MAC-layer + * portion of that header), plus any prefix preceding the + * link-layer header. + */ +static u_int off_macpl; + +/* + * This is 1 if the offset of the beginning of the MAC-layer payload + * from the beginning of the link-layer header is variable-length. + */ +static int off_macpl_is_variable; + +/* + * If the link layer has variable_length headers, "reg_off_macpl" + * is the register number for a register containing the length of the + * link-layer header plus the length of any variable-length header + * preceding the link-layer header. Otherwise, "reg_off_macpl" + * is -1. + */ +static int reg_off_macpl; + +/* + * "off_linktype" is the offset to information in the link-layer header + * giving the packet type. This offset is relative to the beginning + * of the link-layer header (i.e., it doesn't include off_ll). + * + * For Ethernet, it's the offset of the Ethernet type field. + * + * For link-layer types that always use 802.2 headers, it's the + * offset of the LLC header. + * + * For PPP, it's the offset of the PPP type field. + * + * For Cisco HDLC, it's the offset of the CHDLC type field. + * + * For BSD loopback, it's the offset of the AF_ value. + * + * For Linux cooked sockets, it's the offset of the type field. + * + * It's set to -1 for no encapsulation, in which case, IP is assumed. + */ +static u_int off_linktype; + +/* + * TRUE if "pppoes" appeared in the filter; it causes link-layer type + * checks to check the PPP header, assumed to follow a LAN-style link- + * layer header and a PPPoE session header. + */ +static int is_pppoes = 0; + +/* + * TRUE if the link layer includes an ATM pseudo-header. + */ +static int is_atm = 0; + +/* + * TRUE if "lane" appeared in the filter; it causes us to generate + * code that assumes LANE rather than LLC-encapsulated traffic in SunATM. + */ +static int is_lane = 0; + +/* + * These are offsets for the ATM pseudo-header. + */ +static u_int off_vpi; +static u_int off_vci; +static u_int off_proto; + +/* + * These are offsets for the MTP2 fields. + */ +static u_int off_li; + +/* + * These are offsets for the MTP3 fields. + */ +static u_int off_sio; +static u_int off_opc; +static u_int off_dpc; +static u_int off_sls; + +/* + * This is the offset of the first byte after the ATM pseudo_header, + * or -1 if there is no ATM pseudo-header. + */ +static u_int off_payload; + +/* + * These are offsets to the beginning of the network-layer header. + * They are relative to the beginning of the MAC-layer payload (i.e., + * they don't include off_ll or off_macpl). + * + * If the link layer never uses 802.2 LLC: + * + * "off_nl" and "off_nl_nosnap" are the same. + * + * If the link layer always uses 802.2 LLC: + * + * "off_nl" is the offset if there's a SNAP header following + * the 802.2 header; + * + * "off_nl_nosnap" is the offset if there's no SNAP header. + * + * If the link layer is Ethernet: + * + * "off_nl" is the offset if the packet is an Ethernet II packet + * (we assume no 802.3+802.2+SNAP); + * + * "off_nl_nosnap" is the offset if the packet is an 802.3 packet + * with an 802.2 header following it. + */ +static u_int off_nl; +static u_int off_nl_nosnap; + +static int linktype; + +static void +init_linktype(p) + pcap_t *p; +{ + linktype = pcap_datalink(p); +#ifdef PCAP_FDDIPAD + pcap_fddipad = p->fddipad; +#endif + + /* + * Assume it's not raw ATM with a pseudo-header, for now. + */ + off_mac = 0; + is_atm = 0; + is_lane = 0; + off_vpi = -1; + off_vci = -1; + off_proto = -1; + off_payload = -1; + + /* + * And that we're not doing PPPoE. + */ + is_pppoes = 0; + + /* + * And assume we're not doing SS7. + */ + off_li = -1; + off_sio = -1; + off_opc = -1; + off_dpc = -1; + off_sls = -1; + + /* + * Also assume it's not 802.11. + */ + off_ll = 0; + off_macpl = 0; + off_macpl_is_variable = 0; + + orig_linktype = -1; + orig_nl = -1; + label_stack_depth = 0; + + reg_off_ll = -1; + reg_off_macpl = -1; + + switch (linktype) { + + case DLT_ARCNET: + off_linktype = 2; + off_macpl = 6; + off_nl = 0; /* XXX in reality, variable! */ + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_ARCNET_LINUX: + off_linktype = 4; + off_macpl = 8; + off_nl = 0; /* XXX in reality, variable! */ + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_EN10MB: + off_linktype = 12; + off_macpl = 14; /* Ethernet header length */ + off_nl = 0; /* Ethernet II */ + off_nl_nosnap = 3; /* 802.3+802.2 */ + return; + + case DLT_SLIP: + /* + * SLIP doesn't have a link level type. The 16 byte + * header is hacked into our SLIP driver. + */ + off_linktype = -1; + off_macpl = 16; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_SLIP_BSDOS: + /* XXX this may be the same as the DLT_PPP_BSDOS case */ + off_linktype = -1; + /* XXX end */ + off_macpl = 24; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_NULL: + case DLT_LOOP: + off_linktype = 0; + off_macpl = 4; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_ENC: + off_linktype = 0; + off_macpl = 12; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_PPP: + case DLT_PPP_PPPD: + case DLT_C_HDLC: /* BSD/OS Cisco HDLC */ + case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */ + off_linktype = 2; + off_macpl = 4; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_PPP_ETHER: + /* + * This does no include the Ethernet header, and + * only covers session state. + */ + off_linktype = 6; + off_macpl = 8; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_PPP_BSDOS: + off_linktype = 5; + off_macpl = 24; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_FDDI: + /* + * FDDI doesn't really have a link-level type field. + * We set "off_linktype" to the offset of the LLC header. + * + * To check for Ethernet types, we assume that SSAP = SNAP + * is being used and pick out the encapsulated Ethernet type. + * XXX - should we generate code to check for SNAP? + */ + off_linktype = 13; +#ifdef PCAP_FDDIPAD + off_linktype += pcap_fddipad; +#endif + off_macpl = 13; /* FDDI MAC header length */ +#ifdef PCAP_FDDIPAD + off_macpl += pcap_fddipad; +#endif + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_IEEE802: + /* + * Token Ring doesn't really have a link-level type field. + * We set "off_linktype" to the offset of the LLC header. + * + * To check for Ethernet types, we assume that SSAP = SNAP + * is being used and pick out the encapsulated Ethernet type. + * XXX - should we generate code to check for SNAP? + * + * XXX - the header is actually variable-length. + * Some various Linux patched versions gave 38 + * as "off_linktype" and 40 as "off_nl"; however, + * if a token ring packet has *no* routing + * information, i.e. is not source-routed, the correct + * values are 20 and 22, as they are in the vanilla code. + * + * A packet is source-routed iff the uppermost bit + * of the first byte of the source address, at an + * offset of 8, has the uppermost bit set. If the + * packet is source-routed, the total number of bytes + * of routing information is 2 plus bits 0x1F00 of + * the 16-bit value at an offset of 14 (shifted right + * 8 - figure out which byte that is). + */ + off_linktype = 14; + off_macpl = 14; /* Token Ring MAC header length */ + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + /* + * 802.11 doesn't really have a link-level type field. + * We set "off_linktype" to the offset of the LLC header. + * + * To check for Ethernet types, we assume that SSAP = SNAP + * is being used and pick out the encapsulated Ethernet type. + * XXX - should we generate code to check for SNAP? + * + * We also handle variable-length radio headers here. + * The Prism header is in theory variable-length, but in + * practice it's always 144 bytes long. However, some + * drivers on Linux use ARPHRD_IEEE80211_PRISM, but + * sometimes or always supply an AVS header, so we + * have to check whether the radio header is a Prism + * header or an AVS header, so, in practice, it's + * variable-length. + */ + off_linktype = 24; + off_macpl = 0; /* link-layer header is variable-length */ + off_macpl_is_variable = 1; + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_PPI: + /* + * At the moment we treat PPI the same way that we treat + * normal Radiotap encoded packets. The difference is in + * the function that generates the code at the beginning + * to compute the header length. Since this code generator + * of PPI supports bare 802.11 encapsulation only (i.e. + * the encapsulated DLT should be DLT_IEEE802_11) we + * generate code to check for this too. + */ + off_linktype = 24; + off_macpl = 0; /* link-layer header is variable-length */ + off_macpl_is_variable = 1; + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_ATM_RFC1483: + case DLT_ATM_CLIP: /* Linux ATM defines this */ + /* + * assume routed, non-ISO PDUs + * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00) + * + * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS, + * or PPP with the PPP NLPID (e.g., PPPoA)? The + * latter would presumably be treated the way PPPoE + * should be, so you can do "pppoe and udp port 2049" + * or "pppoa and tcp port 80" and have it check for + * PPPo{A,E} and a PPP protocol of IP and.... + */ + off_linktype = 0; + off_macpl = 0; /* packet begins with LLC header */ + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_SUNATM: + /* + * Full Frontal ATM; you get AALn PDUs with an ATM + * pseudo-header. + */ + is_atm = 1; + off_vpi = SUNATM_VPI_POS; + off_vci = SUNATM_VCI_POS; + off_proto = PROTO_POS; + off_mac = -1; /* assume LLC-encapsulated, so no MAC-layer header */ + off_payload = SUNATM_PKT_BEGIN_POS; + off_linktype = off_payload; + off_macpl = off_payload; /* if LLC-encapsulated */ + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_RAW: + case DLT_IPV4: + case DLT_IPV6: + off_linktype = -1; + off_macpl = 0; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_LINUX_SLL: /* fake header for Linux cooked socket */ + off_linktype = 14; + off_macpl = 16; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_LTALK: + /* + * LocalTalk does have a 1-byte type field in the LLAP header, + * but really it just indicates whether there is a "short" or + * "long" DDP packet following. + */ + off_linktype = -1; + off_macpl = 0; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_IP_OVER_FC: + /* + * RFC 2625 IP-over-Fibre-Channel doesn't really have a + * link-level type field. We set "off_linktype" to the + * offset of the LLC header. + * + * To check for Ethernet types, we assume that SSAP = SNAP + * is being used and pick out the encapsulated Ethernet type. + * XXX - should we generate code to check for SNAP? RFC + * 2625 says SNAP should be used. + */ + off_linktype = 16; + off_macpl = 16; + off_nl = 8; /* 802.2+SNAP */ + off_nl_nosnap = 3; /* 802.2 */ + return; + + case DLT_FRELAY: + /* + * XXX - we should set this to handle SNAP-encapsulated + * frames (NLPID of 0x80). + */ + off_linktype = -1; + off_macpl = 0; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + /* + * the only BPF-interesting FRF.16 frames are non-control frames; + * Frame Relay has a variable length link-layer + * so lets start with offset 4 for now and increments later on (FIXME); + */ + case DLT_MFR: + off_linktype = -1; + off_macpl = 0; + off_nl = 4; + off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */ + return; + + case DLT_APPLE_IP_OVER_IEEE1394: + off_linktype = 16; + off_macpl = 18; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; + + case DLT_SYMANTEC_FIREWALL: + off_linktype = 6; + off_macpl = 44; + off_nl = 0; /* Ethernet II */ + off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */ + return; + +#ifdef HAVE_NET_PFVAR_H + case DLT_PFLOG: + off_linktype = 0; + off_macpl = PFLOG_HDRLEN; + off_nl = 0; + off_nl_nosnap = 0; /* no 802.2 LLC */ + return; +#endif + + case DLT_JUNIPER_MFR: + case DLT_JUNIPER_MLFR: + case DLT_JUNIPER_MLPPP: + case DLT_JUNIPER_PPP: + case DLT_JUNIPER_CHDLC: + case DLT_JUNIPER_FRELAY: + off_linktype = 4; + off_macpl = 4; + off_nl = 0; + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_ATM1: + off_linktype = 4; /* in reality variable between 4-8 */ + off_macpl = 4; /* in reality variable between 4-8 */ + off_nl = 0; + off_nl_nosnap = 10; + return; + + case DLT_JUNIPER_ATM2: + off_linktype = 8; /* in reality variable between 8-12 */ + off_macpl = 8; /* in reality variable between 8-12 */ + off_nl = 0; + off_nl_nosnap = 10; + return; + + /* frames captured on a Juniper PPPoE service PIC + * contain raw ethernet frames */ + case DLT_JUNIPER_PPPOE: + case DLT_JUNIPER_ETHER: + off_macpl = 14; + off_linktype = 16; + off_nl = 18; /* Ethernet II */ + off_nl_nosnap = 21; /* 802.3+802.2 */ + return; + + case DLT_JUNIPER_PPPOE_ATM: + off_linktype = 4; + off_macpl = 6; + off_nl = 0; + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_GGSN: + off_linktype = 6; + off_macpl = 12; + off_nl = 0; + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_ES: + off_linktype = 6; + off_macpl = -1; /* not really a network layer but raw IP addresses */ + off_nl = -1; /* not really a network layer but raw IP addresses */ + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_MONITOR: + off_linktype = 12; + off_macpl = 12; + off_nl = 0; /* raw IP/IP6 header */ + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_SERVICES: + off_linktype = 12; + off_macpl = -1; /* L3 proto location dep. on cookie type */ + off_nl = -1; /* L3 proto location dep. on cookie type */ + off_nl_nosnap = -1; /* no 802.2 LLC */ + return; + + case DLT_JUNIPER_VP: + off_linktype = 18; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_JUNIPER_ST: + off_linktype = 18; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_JUNIPER_ISM: + off_linktype = 8; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_JUNIPER_VS: + case DLT_JUNIPER_SRX_E2E: + case DLT_JUNIPER_FIBRECHANNEL: + case DLT_JUNIPER_ATM_CEMIC: + off_linktype = 8; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_MTP2: + off_li = 2; + off_sio = 3; + off_opc = 4; + off_dpc = 4; + off_sls = 7; + off_linktype = -1; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_MTP2_WITH_PHDR: + off_li = 6; + off_sio = 7; + off_opc = 8; + off_dpc = 8; + off_sls = 11; + off_linktype = -1; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_ERF: + off_li = 22; + off_sio = 23; + off_opc = 24; + off_dpc = 24; + off_sls = 27; + off_linktype = -1; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + + case DLT_PFSYNC: + off_linktype = -1; + off_macpl = 4; + off_nl = 0; + off_nl_nosnap = 0; + return; + + case DLT_AX25_KISS: + /* + * Currently, only raw "link[N:M]" filtering is supported. + */ + off_linktype = -1; /* variable, min 15, max 71 steps of 7 */ + off_macpl = -1; + off_nl = -1; /* variable, min 16, max 71 steps of 7 */ + off_nl_nosnap = -1; /* no 802.2 LLC */ + off_mac = 1; /* step over the kiss length byte */ + return; + + case DLT_IPNET: + off_linktype = 1; + off_macpl = 24; /* ipnet header length */ + off_nl = 0; + off_nl_nosnap = -1; + return; + + case DLT_NETANALYZER: + off_mac = 4; /* MAC header is past 4-byte pseudo-header */ + off_linktype = 16; /* includes 4-byte pseudo-header */ + off_macpl = 18; /* pseudo-header+Ethernet header length */ + off_nl = 0; /* Ethernet II */ + off_nl_nosnap = 3; /* 802.3+802.2 */ + return; + + case DLT_NETANALYZER_TRANSPARENT: + off_mac = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */ + off_linktype = 24; /* includes 4-byte pseudo-header+preamble+SFD */ + off_macpl = 26; /* pseudo-header+preamble+SFD+Ethernet header length */ + off_nl = 0; /* Ethernet II */ + off_nl_nosnap = 3; /* 802.3+802.2 */ + return; + + default: + /* + * For values in the range in which we've assigned new + * DLT_ values, only raw "link[N:M]" filtering is supported. + */ + if (linktype >= DLT_MATCHING_MIN && + linktype <= DLT_MATCHING_MAX) { + off_linktype = -1; + off_macpl = -1; + off_nl = -1; + off_nl_nosnap = -1; + return; + } + + } + bpf_error("unknown data link type %d", linktype); + /* NOTREACHED */ +} + +/* + * Load a value relative to the beginning of the link-layer header. + * The link-layer header doesn't necessarily begin at the beginning + * of the packet data; there might be a variable-length prefix containing + * radio information. + */ +static struct slist * +gen_load_llrel(offset, size) + u_int offset, size; +{ + struct slist *s, *s2; + + s = gen_llprefixlen(); + + /* + * If "s" is non-null, it has code to arrange that the X register + * contains the length of the prefix preceding the link-layer + * header. + * + * Otherwise, the length of the prefix preceding the link-layer + * header is "off_ll". + */ + if (s != NULL) { + /* + * There's a variable-length prefix preceding the + * link-layer header. "s" points to a list of statements + * that put the length of that prefix into the X register. + * do an indirect load, to use the X register as an offset. + */ + s2 = new_stmt(BPF_LD|BPF_IND|size); + s2->s.k = offset; + sappend(s, s2); + } else { + /* + * There is no variable-length header preceding the + * link-layer header; add in off_ll, which, if there's + * a fixed-length header preceding the link-layer header, + * is the length of that header. + */ + s = new_stmt(BPF_LD|BPF_ABS|size); + s->s.k = offset + off_ll; + } + return s; +} + +/* + * Load a value relative to the beginning of the MAC-layer payload. + */ +static struct slist * +gen_load_macplrel(offset, size) + u_int offset, size; +{ + struct slist *s, *s2; + + s = gen_off_macpl(); + + /* + * If s is non-null, the offset of the MAC-layer payload is + * variable, and s points to a list of instructions that + * arrange that the X register contains that offset. + * + * Otherwise, the offset of the MAC-layer payload is constant, + * and is in off_macpl. + */ + if (s != NULL) { + /* + * The offset of the MAC-layer payload is in the X + * register. Do an indirect load, to use the X register + * as an offset. + */ + s2 = new_stmt(BPF_LD|BPF_IND|size); + s2->s.k = offset; + sappend(s, s2); + } else { + /* + * The offset of the MAC-layer payload is constant, + * and is in off_macpl; load the value at that offset + * plus the specified offset. + */ + s = new_stmt(BPF_LD|BPF_ABS|size); + s->s.k = off_macpl + offset; + } + return s; +} + +/* + * Load a value relative to the beginning of the specified header. + */ +static struct slist * +gen_load_a(offrel, offset, size) + enum e_offrel offrel; + u_int offset, size; +{ + struct slist *s, *s2; + + switch (offrel) { + + case OR_PACKET: + s = new_stmt(BPF_LD|BPF_ABS|size); + s->s.k = offset; + break; + + case OR_LINK: + s = gen_load_llrel(offset, size); + break; + + case OR_MACPL: + s = gen_load_macplrel(offset, size); + break; + + case OR_NET: + s = gen_load_macplrel(off_nl + offset, size); + break; + + case OR_NET_NOSNAP: + s = gen_load_macplrel(off_nl_nosnap + offset, size); + break; + + case OR_TRAN_IPV4: + /* + * Load the X register with the length of the IPv4 header + * (plus the offset of the link-layer header, if it's + * preceded by a variable-length header such as a radio + * header), in bytes. + */ + s = gen_loadx_iphdrlen(); + + /* + * Load the item at {offset of the MAC-layer payload} + + * {offset, relative to the start of the MAC-layer + * paylod, of the IPv4 header} + {length of the IPv4 header} + + * {specified offset}. + * + * (If the offset of the MAC-layer payload is variable, + * it's included in the value in the X register, and + * off_macpl is 0.) + */ + s2 = new_stmt(BPF_LD|BPF_IND|size); + s2->s.k = off_macpl + off_nl + offset; + sappend(s, s2); + break; + + case OR_TRAN_IPV6: + s = gen_load_macplrel(off_nl + 40 + offset, size); + break; + + default: + abort(); + return NULL; + } + return s; +} + +/* + * Generate code to load into the X register the sum of the length of + * the IPv4 header and any variable-length header preceding the link-layer + * header. + */ +static struct slist * +gen_loadx_iphdrlen() +{ + struct slist *s, *s2; + + s = gen_off_macpl(); + if (s != NULL) { + /* + * There's a variable-length prefix preceding the + * link-layer header, or the link-layer header is itself + * variable-length. "s" points to a list of statements + * that put the offset of the MAC-layer payload into + * the X register. + * + * The 4*([k]&0xf) addressing mode can't be used, as we + * don't have a constant offset, so we have to load the + * value in question into the A register and add to it + * the value from the X register. + */ + s2 = new_stmt(BPF_LD|BPF_IND|BPF_B); + s2->s.k = off_nl; + sappend(s, s2); + s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K); + s2->s.k = 0xf; + sappend(s, s2); + s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K); + s2->s.k = 2; + sappend(s, s2); + + /* + * The A register now contains the length of the + * IP header. We need to add to it the offset of + * the MAC-layer payload, which is still in the X + * register, and move the result into the X register. + */ + sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); + sappend(s, new_stmt(BPF_MISC|BPF_TAX)); + } else { + /* + * There is no variable-length header preceding the + * link-layer header, and the link-layer header is + * fixed-length; load the length of the IPv4 header, + * which is at an offset of off_nl from the beginning + * of the MAC-layer payload, and thus at an offset + * of off_mac_pl + off_nl from the beginning of the + * raw packet data. + */ + s = new_stmt(BPF_LDX|BPF_MSH|BPF_B); + s->s.k = off_macpl + off_nl; + } + return s; +} + +static struct block * +gen_uncond(rsense) + int rsense; +{ + struct block *b; + struct slist *s; + + s = new_stmt(BPF_LD|BPF_IMM); + s->s.k = !rsense; + b = new_block(JMP(BPF_JEQ)); + b->stmts = s; + + return b; +} + +static inline struct block * +gen_true() +{ + return gen_uncond(1); +} + +static inline struct block * +gen_false() +{ + return gen_uncond(0); +} + +/* + * Byte-swap a 32-bit number. + * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on + * big-endian platforms.) + */ +#define SWAPLONG(y) \ +((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) + +/* + * Generate code to match a particular packet type. + * + * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP + * value, if <= ETHERMTU. We use that to determine whether to + * match the type/length field or to check the type/length field for + * a value <= ETHERMTU to see whether it's a type field and then do + * the appropriate test. + */ +static struct block * +gen_ether_linktype(proto) + register int proto; +{ + struct block *b0, *b1; + + switch (proto) { + + case LLCSAP_ISONS: + case LLCSAP_IP: + case LLCSAP_NETBEUI: + /* + * OSI protocols and NetBEUI always use 802.2 encapsulation, + * so we check the DSAP and SSAP. + * + * LLCSAP_IP checks for IP-over-802.2, rather + * than IP-over-Ethernet or IP-over-SNAP. + * + * XXX - should we check both the DSAP and the + * SSAP, like this, or should we check just the + * DSAP, as we do for other types <= ETHERMTU + * (i.e., other SAP values)? + */ + b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); + gen_not(b0); + b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32) + ((proto << 8) | proto)); + gen_and(b0, b1); + return b1; + + case LLCSAP_IPX: + /* + * Check for; + * + * Ethernet_II frames, which are Ethernet + * frames with a frame type of ETHERTYPE_IPX; + * + * Ethernet_802.3 frames, which are 802.3 + * frames (i.e., the type/length field is + * a length field, <= ETHERMTU, rather than + * a type field) with the first two bytes + * after the Ethernet/802.3 header being + * 0xFFFF; + * + * Ethernet_802.2 frames, which are 802.3 + * frames with an 802.2 LLC header and + * with the IPX LSAP as the DSAP in the LLC + * header; + * + * Ethernet_SNAP frames, which are 802.3 + * frames with an LLC header and a SNAP + * header and with an OUI of 0x000000 + * (encapsulated Ethernet) and a protocol + * ID of ETHERTYPE_IPX in the SNAP header. + * + * XXX - should we generate the same code both + * for tests for LLCSAP_IPX and for ETHERTYPE_IPX? + */ + + /* + * This generates code to check both for the + * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3. + */ + b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX); + b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)0xFFFF); + gen_or(b0, b1); + + /* + * Now we add code to check for SNAP frames with + * ETHERTYPE_IPX, i.e. Ethernet_SNAP. + */ + b0 = gen_snap(0x000000, ETHERTYPE_IPX); + gen_or(b0, b1); + + /* + * Now we generate code to check for 802.3 + * frames in general. + */ + b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); + gen_not(b0); + + /* + * Now add the check for 802.3 frames before the + * check for Ethernet_802.2 and Ethernet_802.3, + * as those checks should only be done on 802.3 + * frames, not on Ethernet frames. + */ + gen_and(b0, b1); + + /* + * Now add the check for Ethernet_II frames, and + * do that before checking for the other frame + * types. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)ETHERTYPE_IPX); + gen_or(b0, b1); + return b1; + + case ETHERTYPE_ATALK: + case ETHERTYPE_AARP: + /* + * EtherTalk (AppleTalk protocols on Ethernet link + * layer) may use 802.2 encapsulation. + */ + + /* + * Check for 802.2 encapsulation (EtherTalk phase 2?); + * we check for an Ethernet type field less than + * 1500, which means it's an 802.3 length field. + */ + b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); + gen_not(b0); + + /* + * 802.2-encapsulated ETHERTYPE_ATALK packets are + * SNAP packets with an organization code of + * 0x080007 (Apple, for Appletalk) and a protocol + * type of ETHERTYPE_ATALK (Appletalk). + * + * 802.2-encapsulated ETHERTYPE_AARP packets are + * SNAP packets with an organization code of + * 0x000000 (encapsulated Ethernet) and a protocol + * type of ETHERTYPE_AARP (Appletalk ARP). + */ + if (proto == ETHERTYPE_ATALK) + b1 = gen_snap(0x080007, ETHERTYPE_ATALK); + else /* proto == ETHERTYPE_AARP */ + b1 = gen_snap(0x000000, ETHERTYPE_AARP); + gen_and(b0, b1); + + /* + * Check for Ethernet encapsulation (Ethertalk + * phase 1?); we just check for the Ethernet + * protocol type. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto); + + gen_or(b0, b1); + return b1; + + default: + if (proto <= ETHERMTU) { + /* + * This is an LLC SAP value, so the frames + * that match would be 802.2 frames. + * Check that the frame is an 802.2 frame + * (i.e., that the length/type field is + * a length field, <= ETHERMTU) and + * then check the DSAP. + */ + b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); + gen_not(b0); + b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B, + (bpf_int32)proto); + gen_and(b0, b1); + return b1; + } else { + /* + * This is an Ethernet type, so compare + * the length/type field with it (if + * the frame is an 802.2 frame, the length + * field will be <= ETHERMTU, and, as + * "proto" is > ETHERMTU, this test + * will fail and the frame won't match, + * which is what we want). + */ + return gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)proto); + } + } +} + +/* + * "proto" is an Ethernet type value and for IPNET, if it is not IPv4 + * or IPv6 then we have an error. + */ +static struct block * +gen_ipnet_linktype(proto) + register int proto; +{ + switch (proto) { + + case ETHERTYPE_IP: + return gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)IPH_AF_INET); + /* NOTREACHED */ + + case ETHERTYPE_IPV6: + return gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)IPH_AF_INET6); + /* NOTREACHED */ + + default: + break; + } + + return gen_false(); +} + +/* + * Generate code to match a particular packet type. + * + * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP + * value, if <= ETHERMTU. We use that to determine whether to + * match the type field or to check the type field for the special + * LINUX_SLL_P_802_2 value and then do the appropriate test. + */ +static struct block * +gen_linux_sll_linktype(proto) + register int proto; +{ + struct block *b0, *b1; + + switch (proto) { + + case LLCSAP_ISONS: + case LLCSAP_IP: + case LLCSAP_NETBEUI: + /* + * OSI protocols and NetBEUI always use 802.2 encapsulation, + * so we check the DSAP and SSAP. + * + * LLCSAP_IP checks for IP-over-802.2, rather + * than IP-over-Ethernet or IP-over-SNAP. + * + * XXX - should we check both the DSAP and the + * SSAP, like this, or should we check just the + * DSAP, as we do for other types <= ETHERMTU + * (i.e., other SAP values)? + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); + b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32) + ((proto << 8) | proto)); + gen_and(b0, b1); + return b1; + + case LLCSAP_IPX: + /* + * Ethernet_II frames, which are Ethernet + * frames with a frame type of ETHERTYPE_IPX; + * + * Ethernet_802.3 frames, which have a frame + * type of LINUX_SLL_P_802_3; + * + * Ethernet_802.2 frames, which are 802.3 + * frames with an 802.2 LLC header (i.e, have + * a frame type of LINUX_SLL_P_802_2) and + * with the IPX LSAP as the DSAP in the LLC + * header; + * + * Ethernet_SNAP frames, which are 802.3 + * frames with an LLC header and a SNAP + * header and with an OUI of 0x000000 + * (encapsulated Ethernet) and a protocol + * ID of ETHERTYPE_IPX in the SNAP header. + * + * First, do the checks on LINUX_SLL_P_802_2 + * frames; generate the check for either + * Ethernet_802.2 or Ethernet_SNAP frames, and + * then put a check for LINUX_SLL_P_802_2 frames + * before it. + */ + b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX); + b1 = gen_snap(0x000000, ETHERTYPE_IPX); + gen_or(b0, b1); + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); + gen_and(b0, b1); + + /* + * Now check for 802.3 frames and OR that with + * the previous test. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_3); + gen_or(b0, b1); + + /* + * Now add the check for Ethernet_II frames, and + * do that before checking for the other frame + * types. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)ETHERTYPE_IPX); + gen_or(b0, b1); + return b1; + + case ETHERTYPE_ATALK: + case ETHERTYPE_AARP: + /* + * EtherTalk (AppleTalk protocols on Ethernet link + * layer) may use 802.2 encapsulation. + */ + + /* + * Check for 802.2 encapsulation (EtherTalk phase 2?); + * we check for the 802.2 protocol type in the + * "Ethernet type" field. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); + + /* + * 802.2-encapsulated ETHERTYPE_ATALK packets are + * SNAP packets with an organization code of + * 0x080007 (Apple, for Appletalk) and a protocol + * type of ETHERTYPE_ATALK (Appletalk). + * + * 802.2-encapsulated ETHERTYPE_AARP packets are + * SNAP packets with an organization code of + * 0x000000 (encapsulated Ethernet) and a protocol + * type of ETHERTYPE_AARP (Appletalk ARP). + */ + if (proto == ETHERTYPE_ATALK) + b1 = gen_snap(0x080007, ETHERTYPE_ATALK); + else /* proto == ETHERTYPE_AARP */ + b1 = gen_snap(0x000000, ETHERTYPE_AARP); + gen_and(b0, b1); + + /* + * Check for Ethernet encapsulation (Ethertalk + * phase 1?); we just check for the Ethernet + * protocol type. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto); + + gen_or(b0, b1); + return b1; + + default: + if (proto <= ETHERMTU) { + /* + * This is an LLC SAP value, so the frames + * that match would be 802.2 frames. + * Check for the 802.2 protocol type + * in the "Ethernet type" field, and + * then check the DSAP. + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, + LINUX_SLL_P_802_2); + b1 = gen_cmp(OR_LINK, off_macpl, BPF_B, + (bpf_int32)proto); + gen_and(b0, b1); + return b1; + } else { + /* + * This is an Ethernet type, so compare + * the length/type field with it (if + * the frame is an 802.2 frame, the length + * field will be <= ETHERMTU, and, as + * "proto" is > ETHERMTU, this test + * will fail and the frame won't match, + * which is what we want). + */ + return gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)proto); + } + } +} + +static struct slist * +gen_load_prism_llprefixlen() +{ + struct slist *s1, *s2; + struct slist *sjeq_avs_cookie; + struct slist *sjcommon; + + /* + * This code is not compatible with the optimizer, as + * we are generating jmp instructions within a normal + * slist of instructions + */ + no_optimize = 1; + + /* + * Generate code to load the length of the radio header into + * the register assigned to hold that length, if one has been + * assigned. (If one hasn't been assigned, no code we've + * generated uses that prefix, so we don't need to generate any + * code to load it.) + * + * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes + * or always use the AVS header rather than the Prism header. + * We load a 4-byte big-endian value at the beginning of the + * raw packet data, and see whether, when masked with 0xFFFFF000, + * it's equal to 0x80211000. If so, that indicates that it's + * an AVS header (the masked-out bits are the version number). + * Otherwise, it's a Prism header. + * + * XXX - the Prism header is also, in theory, variable-length, + * but no known software generates headers that aren't 144 + * bytes long. + */ + if (reg_off_ll != -1) { + /* + * Load the cookie. + */ + s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS); + s1->s.k = 0; + + /* + * AND it with 0xFFFFF000. + */ + s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K); + s2->s.k = 0xFFFFF000; + sappend(s1, s2); + + /* + * Compare with 0x80211000. + */ + sjeq_avs_cookie = new_stmt(JMP(BPF_JEQ)); + sjeq_avs_cookie->s.k = 0x80211000; + sappend(s1, sjeq_avs_cookie); + + /* + * If it's AVS: + * + * The 4 bytes at an offset of 4 from the beginning of + * the AVS header are the length of the AVS header. + * That field is big-endian. + */ + s2 = new_stmt(BPF_LD|BPF_W|BPF_ABS); + s2->s.k = 4; + sappend(s1, s2); + sjeq_avs_cookie->s.jt = s2; + + /* + * Now jump to the code to allocate a register + * into which to save the header length and + * store the length there. (The "jump always" + * instruction needs to have the k field set; + * it's added to the PC, so, as we're jumping + * over a single instruction, it should be 1.) + */ + sjcommon = new_stmt(JMP(BPF_JA)); + sjcommon->s.k = 1; + sappend(s1, sjcommon); + + /* + * Now for the code that handles the Prism header. + * Just load the length of the Prism header (144) + * into the A register. Have the test for an AVS + * header branch here if we don't have an AVS header. + */ + s2 = new_stmt(BPF_LD|BPF_W|BPF_IMM); + s2->s.k = 144; + sappend(s1, s2); + sjeq_avs_cookie->s.jf = s2; + + /* + * Now allocate a register to hold that value and store + * it. The code for the AVS header will jump here after + * loading the length of the AVS header. + */ + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_ll; + sappend(s1, s2); + sjcommon->s.jf = s2; + + /* + * Now move it into the X register. + */ + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + return (s1); + } else + return (NULL); +} + +static struct slist * +gen_load_avs_llprefixlen() +{ + struct slist *s1, *s2; + + /* + * Generate code to load the length of the AVS header into + * the register assigned to hold that length, if one has been + * assigned. (If one hasn't been assigned, no code we've + * generated uses that prefix, so we don't need to generate any + * code to load it.) + */ + if (reg_off_ll != -1) { + /* + * The 4 bytes at an offset of 4 from the beginning of + * the AVS header are the length of the AVS header. + * That field is big-endian. + */ + s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS); + s1->s.k = 4; + + /* + * Now allocate a register to hold that value and store + * it. + */ + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_ll; + sappend(s1, s2); + + /* + * Now move it into the X register. + */ + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + return (s1); + } else + return (NULL); +} + +static struct slist * +gen_load_radiotap_llprefixlen() +{ + struct slist *s1, *s2; + + /* + * Generate code to load the length of the radiotap header into + * the register assigned to hold that length, if one has been + * assigned. (If one hasn't been assigned, no code we've + * generated uses that prefix, so we don't need to generate any + * code to load it.) + */ + if (reg_off_ll != -1) { + /* + * The 2 bytes at offsets of 2 and 3 from the beginning + * of the radiotap header are the length of the radiotap + * header; unfortunately, it's little-endian, so we have + * to load it a byte at a time and construct the value. + */ + + /* + * Load the high-order byte, at an offset of 3, shift it + * left a byte, and put the result in the X register. + */ + s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS); + s1->s.k = 3; + s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K); + sappend(s1, s2); + s2->s.k = 8; + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + /* + * Load the next byte, at an offset of 2, and OR the + * value from the X register into it. + */ + s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS); + sappend(s1, s2); + s2->s.k = 2; + s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X); + sappend(s1, s2); + + /* + * Now allocate a register to hold that value and store + * it. + */ + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_ll; + sappend(s1, s2); + + /* + * Now move it into the X register. + */ + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + return (s1); + } else + return (NULL); +} + +/* + * At the moment we treat PPI as normal Radiotap encoded + * packets. The difference is in the function that generates + * the code at the beginning to compute the header length. + * Since this code generator of PPI supports bare 802.11 + * encapsulation only (i.e. the encapsulated DLT should be + * DLT_IEEE802_11) we generate code to check for this too; + * that's done in finish_parse(). + */ +static struct slist * +gen_load_ppi_llprefixlen() +{ + struct slist *s1, *s2; + + /* + * Generate code to load the length of the radiotap header + * into the register assigned to hold that length, if one has + * been assigned. + */ + if (reg_off_ll != -1) { + /* + * The 2 bytes at offsets of 2 and 3 from the beginning + * of the radiotap header are the length of the radiotap + * header; unfortunately, it's little-endian, so we have + * to load it a byte at a time and construct the value. + */ + + /* + * Load the high-order byte, at an offset of 3, shift it + * left a byte, and put the result in the X register. + */ + s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS); + s1->s.k = 3; + s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K); + sappend(s1, s2); + s2->s.k = 8; + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + /* + * Load the next byte, at an offset of 2, and OR the + * value from the X register into it. + */ + s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS); + sappend(s1, s2); + s2->s.k = 2; + s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X); + sappend(s1, s2); + + /* + * Now allocate a register to hold that value and store + * it. + */ + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_ll; + sappend(s1, s2); + + /* + * Now move it into the X register. + */ + s2 = new_stmt(BPF_MISC|BPF_TAX); + sappend(s1, s2); + + return (s1); + } else + return (NULL); +} + +/* + * Load a value relative to the beginning of the link-layer header after the 802.11 + * header, i.e. LLC_SNAP. + * The link-layer header doesn't necessarily begin at the beginning + * of the packet data; there might be a variable-length prefix containing + * radio information. + */ +static struct slist * +gen_load_802_11_header_len(struct slist *s, struct slist *snext) +{ + struct slist *s2; + struct slist *sjset_data_frame_1; + struct slist *sjset_data_frame_2; + struct slist *sjset_qos; + struct slist *sjset_radiotap_flags; + struct slist *sjset_radiotap_tsft; + struct slist *sjset_tsft_datapad, *sjset_notsft_datapad; + struct slist *s_roundup; + + if (reg_off_macpl == -1) { + /* + * No register has been assigned to the offset of + * the MAC-layer payload, which means nobody needs + * it; don't bother computing it - just return + * what we already have. + */ + return (s); + } + + /* + * This code is not compatible with the optimizer, as + * we are generating jmp instructions within a normal + * slist of instructions + */ + no_optimize = 1; + + /* + * If "s" is non-null, it has code to arrange that the X register + * contains the length of the prefix preceding the link-layer + * header. + * + * Otherwise, the length of the prefix preceding the link-layer + * header is "off_ll". + */ + if (s == NULL) { + /* + * There is no variable-length header preceding the + * link-layer header. + * + * Load the length of the fixed-length prefix preceding + * the link-layer header (if any) into the X register, + * and store it in the reg_off_macpl register. + * That length is off_ll. + */ + s = new_stmt(BPF_LDX|BPF_IMM); + s->s.k = off_ll; + } + + /* + * The X register contains the offset of the beginning of the + * link-layer header; add 24, which is the minimum length + * of the MAC header for a data frame, to that, and store it + * in reg_off_macpl, and then load the Frame Control field, + * which is at the offset in the X register, with an indexed load. + */ + s2 = new_stmt(BPF_MISC|BPF_TXA); + sappend(s, s2); + s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s2->s.k = 24; + sappend(s, s2); + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_macpl; + sappend(s, s2); + + s2 = new_stmt(BPF_LD|BPF_IND|BPF_B); + s2->s.k = 0; + sappend(s, s2); + + /* + * Check the Frame Control field to see if this is a data frame; + * a data frame has the 0x08 bit (b3) in that field set and the + * 0x04 bit (b2) clear. + */ + sjset_data_frame_1 = new_stmt(JMP(BPF_JSET)); + sjset_data_frame_1->s.k = 0x08; + sappend(s, sjset_data_frame_1); + + /* + * If b3 is set, test b2, otherwise go to the first statement of + * the rest of the program. + */ + sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(JMP(BPF_JSET)); + sjset_data_frame_2->s.k = 0x04; + sappend(s, sjset_data_frame_2); + sjset_data_frame_1->s.jf = snext; + + /* + * If b2 is not set, this is a data frame; test the QoS bit. + * Otherwise, go to the first statement of the rest of the + * program. + */ + sjset_data_frame_2->s.jt = snext; + sjset_data_frame_2->s.jf = sjset_qos = new_stmt(JMP(BPF_JSET)); + sjset_qos->s.k = 0x80; /* QoS bit */ + sappend(s, sjset_qos); + + /* + * If it's set, add 2 to reg_off_macpl, to skip the QoS + * field. + * Otherwise, go to the first statement of the rest of the + * program. + */ + sjset_qos->s.jt = s2 = new_stmt(BPF_LD|BPF_MEM); + s2->s.k = reg_off_macpl; + sappend(s, s2); + s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM); + s2->s.k = 2; + sappend(s, s2); + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_macpl; + sappend(s, s2); + + /* + * If we have a radiotap header, look at it to see whether + * there's Atheros padding between the MAC-layer header + * and the payload. + * + * Note: all of the fields in the radiotap header are + * little-endian, so we byte-swap all of the values + * we test against, as they will be loaded as big-endian + * values. + */ + if (linktype == DLT_IEEE802_11_RADIO) { + /* + * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set + * in the presence flag? + */ + sjset_qos->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_W); + s2->s.k = 4; + sappend(s, s2); + + sjset_radiotap_flags = new_stmt(JMP(BPF_JSET)); + sjset_radiotap_flags->s.k = SWAPLONG(0x00000002); + sappend(s, sjset_radiotap_flags); + + /* + * If not, skip all of this. + */ + sjset_radiotap_flags->s.jf = snext; + + /* + * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set? + */ + sjset_radiotap_tsft = sjset_radiotap_flags->s.jt = + new_stmt(JMP(BPF_JSET)); + sjset_radiotap_tsft->s.k = SWAPLONG(0x00000001); + sappend(s, sjset_radiotap_tsft); + + /* + * If IEEE80211_RADIOTAP_TSFT is set, the flags field is + * at an offset of 16 from the beginning of the raw packet + * data (8 bytes for the radiotap header and 8 bytes for + * the TSFT field). + * + * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) + * is set. + */ + sjset_radiotap_tsft->s.jt = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B); + s2->s.k = 16; + sappend(s, s2); + + sjset_tsft_datapad = new_stmt(JMP(BPF_JSET)); + sjset_tsft_datapad->s.k = 0x20; + sappend(s, sjset_tsft_datapad); + + /* + * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is + * at an offset of 8 from the beginning of the raw packet + * data (8 bytes for the radiotap header). + * + * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) + * is set. + */ + sjset_radiotap_tsft->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B); + s2->s.k = 8; + sappend(s, s2); + + sjset_notsft_datapad = new_stmt(JMP(BPF_JSET)); + sjset_notsft_datapad->s.k = 0x20; + sappend(s, sjset_notsft_datapad); + + /* + * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is + * set, round the length of the 802.11 header to + * a multiple of 4. Do that by adding 3 and then + * dividing by and multiplying by 4, which we do by + * ANDing with ~3. + */ + s_roundup = new_stmt(BPF_LD|BPF_MEM); + s_roundup->s.k = reg_off_macpl; + sappend(s, s_roundup); + s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM); + s2->s.k = 3; + sappend(s, s2); + s2 = new_stmt(BPF_ALU|BPF_AND|BPF_IMM); + s2->s.k = ~3; + sappend(s, s2); + s2 = new_stmt(BPF_ST); + s2->s.k = reg_off_macpl; + sappend(s, s2); + + sjset_tsft_datapad->s.jt = s_roundup; + sjset_tsft_datapad->s.jf = snext; + sjset_notsft_datapad->s.jt = s_roundup; + sjset_notsft_datapad->s.jf = snext; + } else + sjset_qos->s.jf = snext; + + return s; +} + +static void +insert_compute_vloffsets(b) + struct block *b; +{ + struct slist *s; + + /* + * For link-layer types that have a variable-length header + * preceding the link-layer header, generate code to load + * the offset of the link-layer header into the register + * assigned to that offset, if any. + */ + switch (linktype) { + + case DLT_PRISM_HEADER: + s = gen_load_prism_llprefixlen(); + break; + + case DLT_IEEE802_11_RADIO_AVS: + s = gen_load_avs_llprefixlen(); + break; + + case DLT_IEEE802_11_RADIO: + s = gen_load_radiotap_llprefixlen(); + break; + + case DLT_PPI: + s = gen_load_ppi_llprefixlen(); + break; + + default: + s = NULL; + break; + } + + /* + * For link-layer types that have a variable-length link-layer + * header, generate code to load the offset of the MAC-layer + * payload into the register assigned to that offset, if any. + */ + switch (linktype) { + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + s = gen_load_802_11_header_len(s, b->stmts); + break; + } + + /* + * If we have any offset-loading code, append all the + * existing statements in the block to those statements, + * and make the resulting list the list of statements + * for the block. + */ + if (s != NULL) { + sappend(s, b->stmts); + b->stmts = s; + } +} + +static struct block * +gen_ppi_dlt_check(void) +{ + struct slist *s_load_dlt; + struct block *b; + + if (linktype == DLT_PPI) + { + /* Create the statements that check for the DLT + */ + s_load_dlt = new_stmt(BPF_LD|BPF_W|BPF_ABS); + s_load_dlt->s.k = 4; + + b = new_block(JMP(BPF_JEQ)); + + b->stmts = s_load_dlt; + b->s.k = SWAPLONG(DLT_IEEE802_11); + } + else + { + b = NULL; + } + + return b; +} + +static struct slist * +gen_prism_llprefixlen(void) +{ + struct slist *s; + + if (reg_off_ll == -1) { + /* + * We haven't yet assigned a register for the length + * of the radio header; allocate one. + */ + reg_off_ll = alloc_reg(); + } + + /* + * Load the register containing the radio length + * into the X register. + */ + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = reg_off_ll; + return s; +} + +static struct slist * +gen_avs_llprefixlen(void) +{ + struct slist *s; + + if (reg_off_ll == -1) { + /* + * We haven't yet assigned a register for the length + * of the AVS header; allocate one. + */ + reg_off_ll = alloc_reg(); + } + + /* + * Load the register containing the AVS length + * into the X register. + */ + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = reg_off_ll; + return s; +} + +static struct slist * +gen_radiotap_llprefixlen(void) +{ + struct slist *s; + + if (reg_off_ll == -1) { + /* + * We haven't yet assigned a register for the length + * of the radiotap header; allocate one. + */ + reg_off_ll = alloc_reg(); + } + + /* + * Load the register containing the radiotap length + * into the X register. + */ + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = reg_off_ll; + return s; +} + +/* + * At the moment we treat PPI as normal Radiotap encoded + * packets. The difference is in the function that generates + * the code at the beginning to compute the header length. + * Since this code generator of PPI supports bare 802.11 + * encapsulation only (i.e. the encapsulated DLT should be + * DLT_IEEE802_11) we generate code to check for this too. + */ +static struct slist * +gen_ppi_llprefixlen(void) +{ + struct slist *s; + + if (reg_off_ll == -1) { + /* + * We haven't yet assigned a register for the length + * of the radiotap header; allocate one. + */ + reg_off_ll = alloc_reg(); + } + + /* + * Load the register containing the PPI length + * into the X register. + */ + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = reg_off_ll; + return s; +} + +/* + * Generate code to compute the link-layer header length, if necessary, + * putting it into the X register, and to return either a pointer to a + * "struct slist" for the list of statements in that code, or NULL if + * no code is necessary. + */ +static struct slist * +gen_llprefixlen(void) +{ + switch (linktype) { + + case DLT_PRISM_HEADER: + return gen_prism_llprefixlen(); + + case DLT_IEEE802_11_RADIO_AVS: + return gen_avs_llprefixlen(); + + case DLT_IEEE802_11_RADIO: + return gen_radiotap_llprefixlen(); + + case DLT_PPI: + return gen_ppi_llprefixlen(); + + default: + return NULL; + } +} + +/* + * Generate code to load the register containing the offset of the + * MAC-layer payload into the X register; if no register for that offset + * has been allocated, allocate it first. + */ +static struct slist * +gen_off_macpl(void) +{ + struct slist *s; + + if (off_macpl_is_variable) { + if (reg_off_macpl == -1) { + /* + * We haven't yet assigned a register for the offset + * of the MAC-layer payload; allocate one. + */ + reg_off_macpl = alloc_reg(); + } + + /* + * Load the register containing the offset of the MAC-layer + * payload into the X register. + */ + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = reg_off_macpl; + return s; + } else { + /* + * That offset isn't variable, so we don't need to + * generate any code. + */ + return NULL; + } +} + +/* + * Map an Ethernet type to the equivalent PPP type. + */ +static int +ethertype_to_ppptype(proto) + int proto; +{ + switch (proto) { + + case ETHERTYPE_IP: + proto = PPP_IP; + break; + + case ETHERTYPE_IPV6: + proto = PPP_IPV6; + break; + + case ETHERTYPE_DN: + proto = PPP_DECNET; + break; + + case ETHERTYPE_ATALK: + proto = PPP_APPLE; + break; + + case ETHERTYPE_NS: + proto = PPP_NS; + break; + + case LLCSAP_ISONS: + proto = PPP_OSI; + break; + + case LLCSAP_8021D: + /* + * I'm assuming the "Bridging PDU"s that go + * over PPP are Spanning Tree Protocol + * Bridging PDUs. + */ + proto = PPP_BRPDU; + break; + + case LLCSAP_IPX: + proto = PPP_IPX; + break; + } + return (proto); +} + +/* + * Generate code to match a particular packet type by matching the + * link-layer type field or fields in the 802.2 LLC header. + * + * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP + * value, if <= ETHERMTU. + */ +static struct block * +gen_linktype(proto) + register int proto; +{ + struct block *b0, *b1, *b2; + + /* are we checking MPLS-encapsulated packets? */ + if (label_stack_depth > 0) { + switch (proto) { + case ETHERTYPE_IP: + case PPP_IP: + /* FIXME add other L3 proto IDs */ + return gen_mpls_linktype(Q_IP); + + case ETHERTYPE_IPV6: + case PPP_IPV6: + /* FIXME add other L3 proto IDs */ + return gen_mpls_linktype(Q_IPV6); + + default: + bpf_error("unsupported protocol over mpls"); + /* NOTREACHED */ + } + } + + /* + * Are we testing PPPoE packets? + */ + if (is_pppoes) { + /* + * The PPPoE session header is part of the + * MAC-layer payload, so all references + * should be relative to the beginning of + * that payload. + */ + + /* + * We use Ethernet protocol types inside libpcap; + * map them to the corresponding PPP protocol types. + */ + proto = ethertype_to_ppptype(proto); + return gen_cmp(OR_MACPL, off_linktype, BPF_H, (bpf_int32)proto); + } + + switch (linktype) { + + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + return gen_ether_linktype(proto); + /*NOTREACHED*/ + break; + + case DLT_C_HDLC: + switch (proto) { + + case LLCSAP_ISONS: + proto = (proto << 8 | LLCSAP_ISONS); + /* fall through */ + + default: + return gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)proto); + /*NOTREACHED*/ + break; + } + break; + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + /* + * Check that we have a data frame. + */ + b0 = gen_check_802_11_data_frame(); + + /* + * Now check for the specified link-layer type. + */ + b1 = gen_llc_linktype(proto); + gen_and(b0, b1); + return b1; + /*NOTREACHED*/ + break; + + case DLT_FDDI: + /* + * XXX - check for asynchronous frames, as per RFC 1103. + */ + return gen_llc_linktype(proto); + /*NOTREACHED*/ + break; + + case DLT_IEEE802: + /* + * XXX - check for LLC PDUs, as per IEEE 802.5. + */ + return gen_llc_linktype(proto); + /*NOTREACHED*/ + break; + + case DLT_ATM_RFC1483: + case DLT_ATM_CLIP: + case DLT_IP_OVER_FC: + return gen_llc_linktype(proto); + /*NOTREACHED*/ + break; + + case DLT_SUNATM: + /* + * If "is_lane" is set, check for a LANE-encapsulated + * version of this protocol, otherwise check for an + * LLC-encapsulated version of this protocol. + * + * We assume LANE means Ethernet, not Token Ring. + */ + if (is_lane) { + /* + * Check that the packet doesn't begin with an + * LE Control marker. (We've already generated + * a test for LANE.) + */ + b0 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, + 0xFF00); + gen_not(b0); + + /* + * Now generate an Ethernet test. + */ + b1 = gen_ether_linktype(proto); + gen_and(b0, b1); + return b1; + } else { + /* + * Check for LLC encapsulation and then check the + * protocol. + */ + b0 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); + b1 = gen_llc_linktype(proto); + gen_and(b0, b1); + return b1; + } + /*NOTREACHED*/ + break; + + case DLT_LINUX_SLL: + return gen_linux_sll_linktype(proto); + /*NOTREACHED*/ + break; + + case DLT_SLIP: + case DLT_SLIP_BSDOS: + case DLT_RAW: + /* + * These types don't provide any type field; packets + * are always IPv4 or IPv6. + * + * XXX - for IPv4, check for a version number of 4, and, + * for IPv6, check for a version number of 6? + */ + switch (proto) { + + case ETHERTYPE_IP: + /* Check for a version number of 4. */ + return gen_mcmp(OR_LINK, 0, BPF_B, 0x40, 0xF0); + + case ETHERTYPE_IPV6: + /* Check for a version number of 6. */ + return gen_mcmp(OR_LINK, 0, BPF_B, 0x60, 0xF0); + + default: + return gen_false(); /* always false */ + } + /*NOTREACHED*/ + break; + + case DLT_IPV4: + /* + * Raw IPv4, so no type field. + */ + if (proto == ETHERTYPE_IP) + return gen_true(); /* always true */ + + /* Checking for something other than IPv4; always false */ + return gen_false(); + /*NOTREACHED*/ + break; + + case DLT_IPV6: + /* + * Raw IPv6, so no type field. + */ + if (proto == ETHERTYPE_IPV6) + return gen_true(); /* always true */ + + /* Checking for something other than IPv6; always false */ + return gen_false(); + /*NOTREACHED*/ + break; + + case DLT_PPP: + case DLT_PPP_PPPD: + case DLT_PPP_SERIAL: + case DLT_PPP_ETHER: + /* + * We use Ethernet protocol types inside libpcap; + * map them to the corresponding PPP protocol types. + */ + proto = ethertype_to_ppptype(proto); + return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto); + /*NOTREACHED*/ + break; + + case DLT_PPP_BSDOS: + /* + * We use Ethernet protocol types inside libpcap; + * map them to the corresponding PPP protocol types. + */ + switch (proto) { + + case ETHERTYPE_IP: + /* + * Also check for Van Jacobson-compressed IP. + * XXX - do this for other forms of PPP? + */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_IP); + b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJC); + gen_or(b0, b1); + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJNC); + gen_or(b1, b0); + return b0; + + default: + proto = ethertype_to_ppptype(proto); + return gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)proto); + } + /*NOTREACHED*/ + break; + + case DLT_NULL: + case DLT_LOOP: + case DLT_ENC: + /* + * For DLT_NULL, the link-layer header is a 32-bit + * word containing an AF_ value in *host* byte order, + * and for DLT_ENC, the link-layer header begins + * with a 32-bit work containing an AF_ value in + * host byte order. + * + * In addition, if we're reading a saved capture file, + * the host byte order in the capture may not be the + * same as the host byte order on this machine. + * + * For DLT_LOOP, the link-layer header is a 32-bit + * word containing an AF_ value in *network* byte order. + * + * XXX - AF_ values may, unfortunately, be platform- + * dependent; for example, FreeBSD's AF_INET6 is 24 + * whilst NetBSD's and OpenBSD's is 26. + * + * This means that, when reading a capture file, just + * checking for our AF_INET6 value won't work if the + * capture file came from another OS. + */ + switch (proto) { + + case ETHERTYPE_IP: + proto = AF_INET; + break; + +#ifdef INET6 + case ETHERTYPE_IPV6: + proto = AF_INET6; + break; +#endif + + default: + /* + * Not a type on which we support filtering. + * XXX - support those that have AF_ values + * #defined on this platform, at least? + */ + return gen_false(); + } + + if (linktype == DLT_NULL || linktype == DLT_ENC) { + /* + * The AF_ value is in host byte order, but + * the BPF interpreter will convert it to + * network byte order. + * + * If this is a save file, and it's from a + * machine with the opposite byte order to + * ours, we byte-swap the AF_ value. + * + * Then we run it through "htonl()", and + * generate code to compare against the result. + */ + if (bpf_pcap->sf.rfile != NULL && + bpf_pcap->sf.swapped) + proto = SWAPLONG(proto); + proto = htonl(proto); + } + return (gen_cmp(OR_LINK, 0, BPF_W, (bpf_int32)proto)); + +#ifdef HAVE_NET_PFVAR_H + case DLT_PFLOG: + /* + * af field is host byte order in contrast to the rest of + * the packet. + */ + if (proto == ETHERTYPE_IP) + return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af), + BPF_B, (bpf_int32)AF_INET)); + else if (proto == ETHERTYPE_IPV6) + return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af), + BPF_B, (bpf_int32)AF_INET6)); + else + return gen_false(); + /*NOTREACHED*/ + break; +#endif /* HAVE_NET_PFVAR_H */ + + case DLT_ARCNET: + case DLT_ARCNET_LINUX: + /* + * XXX should we check for first fragment if the protocol + * uses PHDS? + */ + switch (proto) { + + default: + return gen_false(); + + case ETHERTYPE_IPV6: + return (gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_INET6)); + + case ETHERTYPE_IP: + b0 = gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_IP); + b1 = gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_IP_OLD); + gen_or(b0, b1); + return (b1); + + case ETHERTYPE_ARP: + b0 = gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_ARP); + b1 = gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_ARP_OLD); + gen_or(b0, b1); + return (b1); + + case ETHERTYPE_REVARP: + return (gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_REVARP)); + + case ETHERTYPE_ATALK: + return (gen_cmp(OR_LINK, off_linktype, BPF_B, + (bpf_int32)ARCTYPE_ATALK)); + } + /*NOTREACHED*/ + break; + + case DLT_LTALK: + switch (proto) { + case ETHERTYPE_ATALK: + return gen_true(); + default: + return gen_false(); + } + /*NOTREACHED*/ + break; + + case DLT_FRELAY: + /* + * XXX - assumes a 2-byte Frame Relay header with + * DLCI and flags. What if the address is longer? + */ + switch (proto) { + + case ETHERTYPE_IP: + /* + * Check for the special NLPID for IP. + */ + return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0xcc); + + case ETHERTYPE_IPV6: + /* + * Check for the special NLPID for IPv6. + */ + return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0x8e); + + case LLCSAP_ISONS: + /* + * Check for several OSI protocols. + * + * Frame Relay packets typically have an OSI + * NLPID at the beginning; we check for each + * of them. + * + * What we check for is the NLPID and a frame + * control field of UI, i.e. 0x03 followed + * by the NLPID. + */ + b0 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO8473_CLNP); + b1 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO9542_ESIS); + b2 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO10589_ISIS); + gen_or(b1, b2); + gen_or(b0, b2); + return b2; + + default: + return gen_false(); + } + /*NOTREACHED*/ + break; + + case DLT_MFR: + bpf_error("Multi-link Frame Relay link-layer type filtering not implemented"); + + case DLT_JUNIPER_MFR: + case DLT_JUNIPER_MLFR: + case DLT_JUNIPER_MLPPP: + case DLT_JUNIPER_ATM1: + case DLT_JUNIPER_ATM2: + case DLT_JUNIPER_PPPOE: + case DLT_JUNIPER_PPPOE_ATM: + case DLT_JUNIPER_GGSN: + case DLT_JUNIPER_ES: + case DLT_JUNIPER_MONITOR: + case DLT_JUNIPER_SERVICES: + case DLT_JUNIPER_ETHER: + case DLT_JUNIPER_PPP: + case DLT_JUNIPER_FRELAY: + case DLT_JUNIPER_CHDLC: + case DLT_JUNIPER_VP: + case DLT_JUNIPER_ST: + case DLT_JUNIPER_ISM: + case DLT_JUNIPER_VS: + case DLT_JUNIPER_SRX_E2E: + case DLT_JUNIPER_FIBRECHANNEL: + case DLT_JUNIPER_ATM_CEMIC: + + /* just lets verify the magic number for now - + * on ATM we may have up to 6 different encapsulations on the wire + * and need a lot of heuristics to figure out that the payload + * might be; + * + * FIXME encapsulation specific BPF_ filters + */ + return gen_mcmp(OR_LINK, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */ + + case DLT_IPNET: + return gen_ipnet_linktype(proto); + + case DLT_LINUX_IRDA: + bpf_error("IrDA link-layer type filtering not implemented"); + + case DLT_DOCSIS: + bpf_error("DOCSIS link-layer type filtering not implemented"); + + case DLT_MTP2: + case DLT_MTP2_WITH_PHDR: + bpf_error("MTP2 link-layer type filtering not implemented"); + + case DLT_ERF: + bpf_error("ERF link-layer type filtering not implemented"); + + case DLT_PFSYNC: + bpf_error("PFSYNC link-layer type filtering not implemented"); + + case DLT_LINUX_LAPD: + bpf_error("LAPD link-layer type filtering not implemented"); + + case DLT_USB: + case DLT_USB_LINUX: + case DLT_USB_LINUX_MMAPPED: + bpf_error("USB link-layer type filtering not implemented"); + + case DLT_BLUETOOTH_HCI_H4: + case DLT_BLUETOOTH_HCI_H4_WITH_PHDR: + bpf_error("Bluetooth link-layer type filtering not implemented"); + + case DLT_CAN20B: + case DLT_CAN_SOCKETCAN: + bpf_error("CAN link-layer type filtering not implemented"); + + case DLT_IEEE802_15_4: + case DLT_IEEE802_15_4_LINUX: + case DLT_IEEE802_15_4_NONASK_PHY: + case DLT_IEEE802_15_4_NOFCS: + bpf_error("IEEE 802.15.4 link-layer type filtering not implemented"); + + case DLT_IEEE802_16_MAC_CPS_RADIO: + bpf_error("IEEE 802.16 link-layer type filtering not implemented"); + + case DLT_SITA: + bpf_error("SITA link-layer type filtering not implemented"); + + case DLT_RAIF1: + bpf_error("RAIF1 link-layer type filtering not implemented"); + + case DLT_IPMB: + bpf_error("IPMB link-layer type filtering not implemented"); + + case DLT_AX25_KISS: + bpf_error("AX.25 link-layer type filtering not implemented"); + } + + /* + * All the types that have no encapsulation should either be + * handled as DLT_SLIP, DLT_SLIP_BSDOS, and DLT_RAW are, if + * all packets are IP packets, or should be handled in some + * special case, if none of them are (if some are and some + * aren't, the lack of encapsulation is a problem, as we'd + * have to find some other way of determining the packet type). + * + * Therefore, if "off_linktype" is -1, there's an error. + */ + if (off_linktype == (u_int)-1) + abort(); + + /* + * Any type not handled above should always have an Ethernet + * type at an offset of "off_linktype". + */ + return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto); +} + +/* + * Check for an LLC SNAP packet with a given organization code and + * protocol type; we check the entire contents of the 802.2 LLC and + * snap headers, checking for DSAP and SSAP of SNAP and a control + * field of 0x03 in the LLC header, and for the specified organization + * code and protocol type in the SNAP header. + */ +static struct block * +gen_snap(orgcode, ptype) + bpf_u_int32 orgcode; + bpf_u_int32 ptype; +{ + u_char snapblock[8]; + + snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */ + snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */ + snapblock[2] = 0x03; /* control = UI */ + snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */ + snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */ + snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */ + snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */ + snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */ + return gen_bcmp(OR_MACPL, 0, 8, snapblock); +} + +/* + * Generate code to match a particular packet type, for link-layer types + * using 802.2 LLC headers. + * + * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used + * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues. + * + * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP + * value, if <= ETHERMTU. We use that to determine whether to + * match the DSAP or both DSAP and LSAP or to check the OUI and + * protocol ID in a SNAP header. + */ +static struct block * +gen_llc_linktype(proto) + int proto; +{ + /* + * XXX - handle token-ring variable-length header. + */ + switch (proto) { + + case LLCSAP_IP: + case LLCSAP_ISONS: + case LLCSAP_NETBEUI: + /* + * XXX - should we check both the DSAP and the + * SSAP, like this, or should we check just the + * DSAP, as we do for other types <= ETHERMTU + * (i.e., other SAP values)? + */ + return gen_cmp(OR_MACPL, 0, BPF_H, (bpf_u_int32) + ((proto << 8) | proto)); + + case LLCSAP_IPX: + /* + * XXX - are there ever SNAP frames for IPX on + * non-Ethernet 802.x networks? + */ + return gen_cmp(OR_MACPL, 0, BPF_B, + (bpf_int32)LLCSAP_IPX); + + case ETHERTYPE_ATALK: + /* + * 802.2-encapsulated ETHERTYPE_ATALK packets are + * SNAP packets with an organization code of + * 0x080007 (Apple, for Appletalk) and a protocol + * type of ETHERTYPE_ATALK (Appletalk). + * + * XXX - check for an organization code of + * encapsulated Ethernet as well? + */ + return gen_snap(0x080007, ETHERTYPE_ATALK); + + default: + /* + * XXX - we don't have to check for IPX 802.3 + * here, but should we check for the IPX Ethertype? + */ + if (proto <= ETHERMTU) { + /* + * This is an LLC SAP value, so check + * the DSAP. + */ + return gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)proto); + } else { + /* + * This is an Ethernet type; we assume that it's + * unlikely that it'll appear in the right place + * at random, and therefore check only the + * location that would hold the Ethernet type + * in a SNAP frame with an organization code of + * 0x000000 (encapsulated Ethernet). + * + * XXX - if we were to check for the SNAP DSAP and + * LSAP, as per XXX, and were also to check for an + * organization code of 0x000000 (encapsulated + * Ethernet), we'd do + * + * return gen_snap(0x000000, proto); + * + * here; for now, we don't, as per the above. + * I don't know whether it's worth the extra CPU + * time to do the right check or not. + */ + return gen_cmp(OR_MACPL, 6, BPF_H, (bpf_int32)proto); + } + } +} + +static struct block * +gen_hostop(addr, mask, dir, proto, src_off, dst_off) + bpf_u_int32 addr; + bpf_u_int32 mask; + int dir, proto; + u_int src_off, dst_off; +{ + struct block *b0, *b1; + u_int offset; + + switch (dir) { + + case Q_SRC: + offset = src_off; + break; + + case Q_DST: + offset = dst_off; + break; + + case Q_AND: + b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); + b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); + gen_and(b0, b1); + return b1; + + case Q_OR: + case Q_DEFAULT: + b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); + b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); + gen_or(b0, b1); + return b1; + + default: + abort(); + } + b0 = gen_linktype(proto); + b1 = gen_mcmp(OR_NET, offset, BPF_W, (bpf_int32)addr, mask); + gen_and(b0, b1); + return b1; +} + +#ifdef INET6 +static struct block * +gen_hostop6(addr, mask, dir, proto, src_off, dst_off) + struct in6_addr *addr; + struct in6_addr *mask; + int dir, proto; + u_int src_off, dst_off; +{ + struct block *b0, *b1; + u_int offset; + u_int32_t *a, *m; + + switch (dir) { + + case Q_SRC: + offset = src_off; + break; + + case Q_DST: + offset = dst_off; + break; + + case Q_AND: + b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); + b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); + gen_and(b0, b1); + return b1; + + case Q_OR: + case Q_DEFAULT: + b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); + b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); + gen_or(b0, b1); + return b1; + + default: + abort(); + } + /* this order is important */ + a = (u_int32_t *)addr; + m = (u_int32_t *)mask; + b1 = gen_mcmp(OR_NET, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3])); + b0 = gen_mcmp(OR_NET, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2])); + gen_and(b0, b1); + b0 = gen_mcmp(OR_NET, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1])); + gen_and(b0, b1); + b0 = gen_mcmp(OR_NET, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0])); + gen_and(b0, b1); + b0 = gen_linktype(proto); + gen_and(b0, b1); + return b1; +} +#endif + +static struct block * +gen_ehostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + register struct block *b0, *b1; + + switch (dir) { + case Q_SRC: + return gen_bcmp(OR_LINK, off_mac + 6, 6, eaddr); + + case Q_DST: + return gen_bcmp(OR_LINK, off_mac + 0, 6, eaddr); + + case Q_AND: + b0 = gen_ehostop(eaddr, Q_SRC); + b1 = gen_ehostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_ehostop(eaddr, Q_SRC); + b1 = gen_ehostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ADDR1: + bpf_error("'addr1' is only supported on 802.11 with 802.11 headers"); + break; + + case Q_ADDR2: + bpf_error("'addr2' is only supported on 802.11 with 802.11 headers"); + break; + + case Q_ADDR3: + bpf_error("'addr3' is only supported on 802.11 with 802.11 headers"); + break; + + case Q_ADDR4: + bpf_error("'addr4' is only supported on 802.11 with 802.11 headers"); + break; + + case Q_RA: + bpf_error("'ra' is only supported on 802.11 with 802.11 headers"); + break; + + case Q_TA: + bpf_error("'ta' is only supported on 802.11 with 802.11 headers"); + break; + } + abort(); + /* NOTREACHED */ +} + +/* + * Like gen_ehostop, but for DLT_FDDI + */ +static struct block * +gen_fhostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + struct block *b0, *b1; + + switch (dir) { + case Q_SRC: +#ifdef PCAP_FDDIPAD + return gen_bcmp(OR_LINK, 6 + 1 + pcap_fddipad, 6, eaddr); +#else + return gen_bcmp(OR_LINK, 6 + 1, 6, eaddr); +#endif + + case Q_DST: +#ifdef PCAP_FDDIPAD + return gen_bcmp(OR_LINK, 0 + 1 + pcap_fddipad, 6, eaddr); +#else + return gen_bcmp(OR_LINK, 0 + 1, 6, eaddr); +#endif + + case Q_AND: + b0 = gen_fhostop(eaddr, Q_SRC); + b1 = gen_fhostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_fhostop(eaddr, Q_SRC); + b1 = gen_fhostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ADDR1: + bpf_error("'addr1' is only supported on 802.11"); + break; + + case Q_ADDR2: + bpf_error("'addr2' is only supported on 802.11"); + break; + + case Q_ADDR3: + bpf_error("'addr3' is only supported on 802.11"); + break; + + case Q_ADDR4: + bpf_error("'addr4' is only supported on 802.11"); + break; + + case Q_RA: + bpf_error("'ra' is only supported on 802.11"); + break; + + case Q_TA: + bpf_error("'ta' is only supported on 802.11"); + break; + } + abort(); + /* NOTREACHED */ +} + +/* + * Like gen_ehostop, but for DLT_IEEE802 (Token Ring) + */ +static struct block * +gen_thostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + register struct block *b0, *b1; + + switch (dir) { + case Q_SRC: + return gen_bcmp(OR_LINK, 8, 6, eaddr); + + case Q_DST: + return gen_bcmp(OR_LINK, 2, 6, eaddr); + + case Q_AND: + b0 = gen_thostop(eaddr, Q_SRC); + b1 = gen_thostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_thostop(eaddr, Q_SRC); + b1 = gen_thostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ADDR1: + bpf_error("'addr1' is only supported on 802.11"); + break; + + case Q_ADDR2: + bpf_error("'addr2' is only supported on 802.11"); + break; + + case Q_ADDR3: + bpf_error("'addr3' is only supported on 802.11"); + break; + + case Q_ADDR4: + bpf_error("'addr4' is only supported on 802.11"); + break; + + case Q_RA: + bpf_error("'ra' is only supported on 802.11"); + break; + + case Q_TA: + bpf_error("'ta' is only supported on 802.11"); + break; + } + abort(); + /* NOTREACHED */ +} + +/* + * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and + * various 802.11 + radio headers. + */ +static struct block * +gen_wlanhostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + register struct block *b0, *b1, *b2; + register struct slist *s; + +#ifdef ENABLE_WLAN_FILTERING_PATCH + /* + * TODO GV 20070613 + * We need to disable the optimizer because the optimizer is buggy + * and wipes out some LD instructions generated by the below + * code to validate the Frame Control bits + */ + no_optimize = 1; +#endif /* ENABLE_WLAN_FILTERING_PATCH */ + + switch (dir) { + case Q_SRC: + /* + * Oh, yuk. + * + * For control frames, there is no SA. + * + * For management frames, SA is at an + * offset of 10 from the beginning of + * the packet. + * + * For data frames, SA is at an offset + * of 10 from the beginning of the packet + * if From DS is clear, at an offset of + * 16 from the beginning of the packet + * if From DS is set and To DS is clear, + * and an offset of 24 from the beginning + * of the packet if From DS is set and To DS + * is set. + */ + + /* + * Generate the tests to be done for data frames + * with From DS set. + * + * First, check for To DS set, i.e. check "link[1] & 0x01". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x01; /* To DS */ + b1->stmts = s; + + /* + * If To DS is set, the SA is at 24. + */ + b0 = gen_bcmp(OR_LINK, 24, 6, eaddr); + gen_and(b1, b0); + + /* + * Now, check for To DS not set, i.e. check + * "!(link[1] & 0x01)". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x01; /* To DS */ + b2->stmts = s; + gen_not(b2); + + /* + * If To DS is not set, the SA is at 16. + */ + b1 = gen_bcmp(OR_LINK, 16, 6, eaddr); + gen_and(b2, b1); + + /* + * Now OR together the last two checks. That gives + * the complete set of checks for data frames with + * From DS set. + */ + gen_or(b1, b0); + + /* + * Now check for From DS being set, and AND that with + * the ORed-together checks. + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x02; /* From DS */ + b1->stmts = s; + gen_and(b1, b0); + + /* + * Now check for data frames with From DS not set. + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x02; /* From DS */ + b2->stmts = s; + gen_not(b2); + + /* + * If From DS isn't set, the SA is at 10. + */ + b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); + gen_and(b2, b1); + + /* + * Now OR together the checks for data frames with + * From DS not set and for data frames with From DS + * set; that gives the checks done for data frames. + */ + gen_or(b1, b0); + + /* + * Now check for a data frame. + * I.e, check "link[0] & 0x08". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x08; + b1->stmts = s; + + /* + * AND that with the checks done for data frames. + */ + gen_and(b1, b0); + + /* + * If the high-order bit of the type value is 0, this + * is a management frame. + * I.e, check "!(link[0] & 0x08)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x08; + b2->stmts = s; + gen_not(b2); + + /* + * For management frames, the SA is at 10. + */ + b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); + gen_and(b2, b1); + + /* + * OR that with the checks done for data frames. + * That gives the checks done for management and + * data frames. + */ + gen_or(b1, b0); + + /* + * If the low-order bit of the type value is 1, + * this is either a control frame or a frame + * with a reserved type, and thus not a + * frame with an SA. + * + * I.e., check "!(link[0] & 0x04)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x04; + b1->stmts = s; + gen_not(b1); + + /* + * AND that with the checks for data and management + * frames. + */ + gen_and(b1, b0); + return b0; + + case Q_DST: + /* + * Oh, yuk. + * + * For control frames, there is no DA. + * + * For management frames, DA is at an + * offset of 4 from the beginning of + * the packet. + * + * For data frames, DA is at an offset + * of 4 from the beginning of the packet + * if To DS is clear and at an offset of + * 16 from the beginning of the packet + * if To DS is set. + */ + + /* + * Generate the tests to be done for data frames. + * + * First, check for To DS set, i.e. "link[1] & 0x01". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x01; /* To DS */ + b1->stmts = s; + + /* + * If To DS is set, the DA is at 16. + */ + b0 = gen_bcmp(OR_LINK, 16, 6, eaddr); + gen_and(b1, b0); + + /* + * Now, check for To DS not set, i.e. check + * "!(link[1] & 0x01)". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x01; /* To DS */ + b2->stmts = s; + gen_not(b2); + + /* + * If To DS is not set, the DA is at 4. + */ + b1 = gen_bcmp(OR_LINK, 4, 6, eaddr); + gen_and(b2, b1); + + /* + * Now OR together the last two checks. That gives + * the complete set of checks for data frames. + */ + gen_or(b1, b0); + + /* + * Now check for a data frame. + * I.e, check "link[0] & 0x08". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x08; + b1->stmts = s; + + /* + * AND that with the checks done for data frames. + */ + gen_and(b1, b0); + + /* + * If the high-order bit of the type value is 0, this + * is a management frame. + * I.e, check "!(link[0] & 0x08)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x08; + b2->stmts = s; + gen_not(b2); + + /* + * For management frames, the DA is at 4. + */ + b1 = gen_bcmp(OR_LINK, 4, 6, eaddr); + gen_and(b2, b1); + + /* + * OR that with the checks done for data frames. + * That gives the checks done for management and + * data frames. + */ + gen_or(b1, b0); + + /* + * If the low-order bit of the type value is 1, + * this is either a control frame or a frame + * with a reserved type, and thus not a + * frame with an SA. + * + * I.e., check "!(link[0] & 0x04)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x04; + b1->stmts = s; + gen_not(b1); + + /* + * AND that with the checks for data and management + * frames. + */ + gen_and(b1, b0); + return b0; + + case Q_RA: + /* + * Not present in management frames; addr1 in other + * frames. + */ + + /* + * If the high-order bit of the type value is 0, this + * is a management frame. + * I.e, check "(link[0] & 0x08)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x08; + b1->stmts = s; + + /* + * Check addr1. + */ + b0 = gen_bcmp(OR_LINK, 4, 6, eaddr); + + /* + * AND that with the check of addr1. + */ + gen_and(b1, b0); + return (b0); + + case Q_TA: + /* + * Not present in management frames; addr2, if present, + * in other frames. + */ + + /* + * Not present in CTS or ACK control frames. + */ + b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, + IEEE80211_FC0_TYPE_MASK); + gen_not(b0); + b1 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS, + IEEE80211_FC0_SUBTYPE_MASK); + gen_not(b1); + b2 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK, + IEEE80211_FC0_SUBTYPE_MASK); + gen_not(b2); + gen_and(b1, b2); + gen_or(b0, b2); + + /* + * If the high-order bit of the type value is 0, this + * is a management frame. + * I.e, check "(link[0] & 0x08)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x08; + b1->stmts = s; + + /* + * AND that with the check for frames other than + * CTS and ACK frames. + */ + gen_and(b1, b2); + + /* + * Check addr2. + */ + b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); + gen_and(b2, b1); + return b1; + + /* + * XXX - add BSSID keyword? + */ + case Q_ADDR1: + return (gen_bcmp(OR_LINK, 4, 6, eaddr)); + + case Q_ADDR2: + /* + * Not present in CTS or ACK control frames. + */ + b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, + IEEE80211_FC0_TYPE_MASK); + gen_not(b0); + b1 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS, + IEEE80211_FC0_SUBTYPE_MASK); + gen_not(b1); + b2 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK, + IEEE80211_FC0_SUBTYPE_MASK); + gen_not(b2); + gen_and(b1, b2); + gen_or(b0, b2); + b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); + gen_and(b2, b1); + return b1; + + case Q_ADDR3: + /* + * Not present in control frames. + */ + b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, + IEEE80211_FC0_TYPE_MASK); + gen_not(b0); + b1 = gen_bcmp(OR_LINK, 16, 6, eaddr); + gen_and(b0, b1); + return b1; + + case Q_ADDR4: + /* + * Present only if the direction mask has both "From DS" + * and "To DS" set. Neither control frames nor management + * frames should have both of those set, so we don't + * check the frame type. + */ + b0 = gen_mcmp(OR_LINK, 1, BPF_B, + IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK); + b1 = gen_bcmp(OR_LINK, 24, 6, eaddr); + gen_and(b0, b1); + return b1; + + case Q_AND: + b0 = gen_wlanhostop(eaddr, Q_SRC); + b1 = gen_wlanhostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_wlanhostop(eaddr, Q_SRC); + b1 = gen_wlanhostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + } + abort(); + /* NOTREACHED */ +} + +/* + * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel. + * (We assume that the addresses are IEEE 48-bit MAC addresses, + * as the RFC states.) + */ +static struct block * +gen_ipfchostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + register struct block *b0, *b1; + + switch (dir) { + case Q_SRC: + return gen_bcmp(OR_LINK, 10, 6, eaddr); + + case Q_DST: + return gen_bcmp(OR_LINK, 2, 6, eaddr); + + case Q_AND: + b0 = gen_ipfchostop(eaddr, Q_SRC); + b1 = gen_ipfchostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_ipfchostop(eaddr, Q_SRC); + b1 = gen_ipfchostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ADDR1: + bpf_error("'addr1' is only supported on 802.11"); + break; + + case Q_ADDR2: + bpf_error("'addr2' is only supported on 802.11"); + break; + + case Q_ADDR3: + bpf_error("'addr3' is only supported on 802.11"); + break; + + case Q_ADDR4: + bpf_error("'addr4' is only supported on 802.11"); + break; + + case Q_RA: + bpf_error("'ra' is only supported on 802.11"); + break; + + case Q_TA: + bpf_error("'ta' is only supported on 802.11"); + break; + } + abort(); + /* NOTREACHED */ +} + +/* + * This is quite tricky because there may be pad bytes in front of the + * DECNET header, and then there are two possible data packet formats that + * carry both src and dst addresses, plus 5 packet types in a format that + * carries only the src node, plus 2 types that use a different format and + * also carry just the src node. + * + * Yuck. + * + * Instead of doing those all right, we just look for data packets with + * 0 or 1 bytes of padding. If you want to look at other packets, that + * will require a lot more hacking. + * + * To add support for filtering on DECNET "areas" (network numbers) + * one would want to add a "mask" argument to this routine. That would + * make the filter even more inefficient, although one could be clever + * and not generate masking instructions if the mask is 0xFFFF. + */ +static struct block * +gen_dnhostop(addr, dir) + bpf_u_int32 addr; + int dir; +{ + struct block *b0, *b1, *b2, *tmp; + u_int offset_lh; /* offset if long header is received */ + u_int offset_sh; /* offset if short header is received */ + + switch (dir) { + + case Q_DST: + offset_sh = 1; /* follows flags */ + offset_lh = 7; /* flgs,darea,dsubarea,HIORD */ + break; + + case Q_SRC: + offset_sh = 3; /* follows flags, dstnode */ + offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */ + break; + + case Q_AND: + /* Inefficient because we do our Calvinball dance twice */ + b0 = gen_dnhostop(addr, Q_SRC); + b1 = gen_dnhostop(addr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_OR: + case Q_DEFAULT: + /* Inefficient because we do our Calvinball dance twice */ + b0 = gen_dnhostop(addr, Q_SRC); + b1 = gen_dnhostop(addr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ISO: + bpf_error("ISO host filtering not implemented"); + + default: + abort(); + } + b0 = gen_linktype(ETHERTYPE_DN); + /* Check for pad = 1, long header case */ + tmp = gen_mcmp(OR_NET, 2, BPF_H, + (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF)); + b1 = gen_cmp(OR_NET, 2 + 1 + offset_lh, + BPF_H, (bpf_int32)ntohs((u_short)addr)); + gen_and(tmp, b1); + /* Check for pad = 0, long header case */ + tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7); + b2 = gen_cmp(OR_NET, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr)); + gen_and(tmp, b2); + gen_or(b2, b1); + /* Check for pad = 1, short header case */ + tmp = gen_mcmp(OR_NET, 2, BPF_H, + (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF)); + b2 = gen_cmp(OR_NET, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr)); + gen_and(tmp, b2); + gen_or(b2, b1); + /* Check for pad = 0, short header case */ + tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7); + b2 = gen_cmp(OR_NET, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr)); + gen_and(tmp, b2); + gen_or(b2, b1); + + /* Combine with test for linktype */ + gen_and(b0, b1); + return b1; +} + +/* + * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets; + * test the bottom-of-stack bit, and then check the version number + * field in the IP header. + */ +static struct block * +gen_mpls_linktype(proto) + int proto; +{ + struct block *b0, *b1; + + switch (proto) { + + case Q_IP: + /* match the bottom-of-stack bit */ + b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01); + /* match the IPv4 version number */ + b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x40, 0xf0); + gen_and(b0, b1); + return b1; + + case Q_IPV6: + /* match the bottom-of-stack bit */ + b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01); + /* match the IPv4 version number */ + b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x60, 0xf0); + gen_and(b0, b1); + return b1; + + default: + abort(); + } +} + +static struct block * +gen_host(addr, mask, proto, dir, type) + bpf_u_int32 addr; + bpf_u_int32 mask; + int proto; + int dir; + int type; +{ + struct block *b0, *b1; + const char *typestr; + + if (type == Q_NET) + typestr = "net"; + else + typestr = "host"; + + switch (proto) { + + case Q_DEFAULT: + b0 = gen_host(addr, mask, Q_IP, dir, type); + /* + * Only check for non-IPv4 addresses if we're not + * checking MPLS-encapsulated packets. + */ + if (label_stack_depth == 0) { + b1 = gen_host(addr, mask, Q_ARP, dir, type); + gen_or(b0, b1); + b0 = gen_host(addr, mask, Q_RARP, dir, type); + gen_or(b1, b0); + } + return b0; + + case Q_IP: + return gen_hostop(addr, mask, dir, ETHERTYPE_IP, 12, 16); + + case Q_RARP: + return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP, 14, 24); + + case Q_ARP: + return gen_hostop(addr, mask, dir, ETHERTYPE_ARP, 14, 24); + + case Q_TCP: + bpf_error("'tcp' modifier applied to %s", typestr); + + case Q_SCTP: + bpf_error("'sctp' modifier applied to %s", typestr); + + case Q_UDP: + bpf_error("'udp' modifier applied to %s", typestr); + + case Q_ICMP: + bpf_error("'icmp' modifier applied to %s", typestr); + + case Q_IGMP: + bpf_error("'igmp' modifier applied to %s", typestr); + + case Q_IGRP: + bpf_error("'igrp' modifier applied to %s", typestr); + + case Q_PIM: + bpf_error("'pim' modifier applied to %s", typestr); + + case Q_VRRP: + bpf_error("'vrrp' modifier applied to %s", typestr); + + case Q_CARP: + bpf_error("'carp' modifier applied to %s", typestr); + + case Q_ATALK: + bpf_error("ATALK host filtering not implemented"); + + case Q_AARP: + bpf_error("AARP host filtering not implemented"); + + case Q_DECNET: + return gen_dnhostop(addr, dir); + + case Q_SCA: + bpf_error("SCA host filtering not implemented"); + + case Q_LAT: + bpf_error("LAT host filtering not implemented"); + + case Q_MOPDL: + bpf_error("MOPDL host filtering not implemented"); + + case Q_MOPRC: + bpf_error("MOPRC host filtering not implemented"); + + case Q_IPV6: + bpf_error("'ip6' modifier applied to ip host"); + + case Q_ICMPV6: + bpf_error("'icmp6' modifier applied to %s", typestr); + + case Q_AH: + bpf_error("'ah' modifier applied to %s", typestr); + + case Q_ESP: + bpf_error("'esp' modifier applied to %s", typestr); + + case Q_ISO: + bpf_error("ISO host filtering not implemented"); + + case Q_ESIS: + bpf_error("'esis' modifier applied to %s", typestr); + + case Q_ISIS: + bpf_error("'isis' modifier applied to %s", typestr); + + case Q_CLNP: + bpf_error("'clnp' modifier applied to %s", typestr); + + case Q_STP: + bpf_error("'stp' modifier applied to %s", typestr); + + case Q_IPX: + bpf_error("IPX host filtering not implemented"); + + case Q_NETBEUI: + bpf_error("'netbeui' modifier applied to %s", typestr); + + case Q_RADIO: + bpf_error("'radio' modifier applied to %s", typestr); + + default: + abort(); + } + /* NOTREACHED */ +} + +#ifdef INET6 +static struct block * +gen_host6(addr, mask, proto, dir, type) + struct in6_addr *addr; + struct in6_addr *mask; + int proto; + int dir; + int type; +{ + const char *typestr; + + if (type == Q_NET) + typestr = "net"; + else + typestr = "host"; + + switch (proto) { + + case Q_DEFAULT: + return gen_host6(addr, mask, Q_IPV6, dir, type); + + case Q_IP: + bpf_error("'ip' modifier applied to ip6 %s", typestr); + + case Q_RARP: + bpf_error("'rarp' modifier applied to ip6 %s", typestr); + + case Q_ARP: + bpf_error("'arp' modifier applied to ip6 %s", typestr); + + case Q_SCTP: + bpf_error("'sctp' modifier applied to %s", typestr); + + case Q_TCP: + bpf_error("'tcp' modifier applied to %s", typestr); + + case Q_UDP: + bpf_error("'udp' modifier applied to %s", typestr); + + case Q_ICMP: + bpf_error("'icmp' modifier applied to %s", typestr); + + case Q_IGMP: + bpf_error("'igmp' modifier applied to %s", typestr); + + case Q_IGRP: + bpf_error("'igrp' modifier applied to %s", typestr); + + case Q_PIM: + bpf_error("'pim' modifier applied to %s", typestr); + + case Q_VRRP: + bpf_error("'vrrp' modifier applied to %s", typestr); + + case Q_CARP: + bpf_error("'carp' modifier applied to %s", typestr); + + case Q_ATALK: + bpf_error("ATALK host filtering not implemented"); + + case Q_AARP: + bpf_error("AARP host filtering not implemented"); + + case Q_DECNET: + bpf_error("'decnet' modifier applied to ip6 %s", typestr); + + case Q_SCA: + bpf_error("SCA host filtering not implemented"); + + case Q_LAT: + bpf_error("LAT host filtering not implemented"); + + case Q_MOPDL: + bpf_error("MOPDL host filtering not implemented"); + + case Q_MOPRC: + bpf_error("MOPRC host filtering not implemented"); + + case Q_IPV6: + return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6, 8, 24); + + case Q_ICMPV6: + bpf_error("'icmp6' modifier applied to %s", typestr); + + case Q_AH: + bpf_error("'ah' modifier applied to %s", typestr); + + case Q_ESP: + bpf_error("'esp' modifier applied to %s", typestr); + + case Q_ISO: + bpf_error("ISO host filtering not implemented"); + + case Q_ESIS: + bpf_error("'esis' modifier applied to %s", typestr); + + case Q_ISIS: + bpf_error("'isis' modifier applied to %s", typestr); + + case Q_CLNP: + bpf_error("'clnp' modifier applied to %s", typestr); + + case Q_STP: + bpf_error("'stp' modifier applied to %s", typestr); + + case Q_IPX: + bpf_error("IPX host filtering not implemented"); + + case Q_NETBEUI: + bpf_error("'netbeui' modifier applied to %s", typestr); + + case Q_RADIO: + bpf_error("'radio' modifier applied to %s", typestr); + + default: + abort(); + } + /* NOTREACHED */ +} +#endif + +#ifndef INET6 +static struct block * +gen_gateway(eaddr, alist, proto, dir) + const u_char *eaddr; + bpf_u_int32 **alist; + int proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + if (dir != 0) + bpf_error("direction applied to 'gateway'"); + + switch (proto) { + case Q_DEFAULT: + case Q_IP: + case Q_ARP: + case Q_RARP: + switch (linktype) { + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + b0 = gen_ehostop(eaddr, Q_OR); + break; + case DLT_FDDI: + b0 = gen_fhostop(eaddr, Q_OR); + break; + case DLT_IEEE802: + b0 = gen_thostop(eaddr, Q_OR); + break; + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + b0 = gen_wlanhostop(eaddr, Q_OR); + break; + case DLT_SUNATM: + if (!is_lane) + bpf_error( + "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); + /* + * Check that the packet doesn't begin with an + * LE Control marker. (We've already generated + * a test for LANE.) + */ + b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, + BPF_H, 0xFF00); + gen_not(b1); + + /* + * Now check the MAC address. + */ + b0 = gen_ehostop(eaddr, Q_OR); + gen_and(b1, b0); + break; + case DLT_IP_OVER_FC: + b0 = gen_ipfchostop(eaddr, Q_OR); + break; + default: + bpf_error( + "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); + } + b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR, Q_HOST); + while (*alist) { + tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR, + Q_HOST); + gen_or(b1, tmp); + b1 = tmp; + } + gen_not(b1); + gen_and(b0, b1); + return b1; + } + bpf_error("illegal modifier of 'gateway'"); + /* NOTREACHED */ +} +#endif + +struct block * +gen_proto_abbrev(proto) + int proto; +{ + struct block *b0; + struct block *b1; + + switch (proto) { + + case Q_SCTP: + b1 = gen_proto(IPPROTO_SCTP, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_SCTP, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_TCP: + b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_UDP: + b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ICMP: + b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT); + break; + +#ifndef IPPROTO_IGMP +#define IPPROTO_IGMP 2 +#endif + + case Q_IGMP: + b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT); + break; + +#ifndef IPPROTO_IGRP +#define IPPROTO_IGRP 9 +#endif + case Q_IGRP: + b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT); + break; + +#ifndef IPPROTO_PIM +#define IPPROTO_PIM 103 +#endif + + case Q_PIM: + b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + +#ifndef IPPROTO_VRRP +#define IPPROTO_VRRP 112 +#endif + + case Q_VRRP: + b1 = gen_proto(IPPROTO_VRRP, Q_IP, Q_DEFAULT); + break; + +#ifndef IPPROTO_CARP +#define IPPROTO_CARP 112 +#endif + + case Q_CARP: + b1 = gen_proto(IPPROTO_CARP, Q_IP, Q_DEFAULT); + break; + + case Q_IP: + b1 = gen_linktype(ETHERTYPE_IP); + break; + + case Q_ARP: + b1 = gen_linktype(ETHERTYPE_ARP); + break; + + case Q_RARP: + b1 = gen_linktype(ETHERTYPE_REVARP); + break; + + case Q_LINK: + bpf_error("link layer applied in wrong context"); + + case Q_ATALK: + b1 = gen_linktype(ETHERTYPE_ATALK); + break; + + case Q_AARP: + b1 = gen_linktype(ETHERTYPE_AARP); + break; + + case Q_DECNET: + b1 = gen_linktype(ETHERTYPE_DN); + break; + + case Q_SCA: + b1 = gen_linktype(ETHERTYPE_SCA); + break; + + case Q_LAT: + b1 = gen_linktype(ETHERTYPE_LAT); + break; + + case Q_MOPDL: + b1 = gen_linktype(ETHERTYPE_MOPDL); + break; + + case Q_MOPRC: + b1 = gen_linktype(ETHERTYPE_MOPRC); + break; + + case Q_IPV6: + b1 = gen_linktype(ETHERTYPE_IPV6); + break; + +#ifndef IPPROTO_ICMPV6 +#define IPPROTO_ICMPV6 58 +#endif + case Q_ICMPV6: + b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT); + break; + +#ifndef IPPROTO_AH +#define IPPROTO_AH 51 +#endif + case Q_AH: + b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + +#ifndef IPPROTO_ESP +#define IPPROTO_ESP 50 +#endif + case Q_ESP: + b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT); + b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISO: + b1 = gen_linktype(LLCSAP_ISONS); + break; + + case Q_ESIS: + b1 = gen_proto(ISO9542_ESIS, Q_ISO, Q_DEFAULT); + break; + + case Q_ISIS: + b1 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT); + break; + + case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */ + b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ + gen_or(b0, b1); + b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */ + b0 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ + gen_or(b0, b1); + b0 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */ + b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_LSP: + b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_SNP: + b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_CSNP: + b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_ISIS_PSNP: + b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); + b1 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); + gen_or(b0, b1); + break; + + case Q_CLNP: + b1 = gen_proto(ISO8473_CLNP, Q_ISO, Q_DEFAULT); + break; + + case Q_STP: + b1 = gen_linktype(LLCSAP_8021D); + break; + + case Q_IPX: + b1 = gen_linktype(LLCSAP_IPX); + break; + + case Q_NETBEUI: + b1 = gen_linktype(LLCSAP_NETBEUI); + break; + + case Q_RADIO: + bpf_error("'radio' is not a valid protocol type"); + + default: + abort(); + } + return b1; +} + +static struct block * +gen_ipfrag() +{ + struct slist *s; + struct block *b; + + /* not IPv4 frag other than the first frag */ + s = gen_load_a(OR_NET, 6, BPF_H); + b = new_block(JMP(BPF_JSET)); + b->s.k = 0x1fff; + b->stmts = s; + gen_not(b); + + return b; +} + +/* + * Generate a comparison to a port value in the transport-layer header + * at the specified offset from the beginning of that header. + * + * XXX - this handles a variable-length prefix preceding the link-layer + * header, such as the radiotap or AVS radio prefix, but doesn't handle + * variable-length link-layer headers (such as Token Ring or 802.11 + * headers). + */ +static struct block * +gen_portatom(off, v) + int off; + bpf_int32 v; +{ + return gen_cmp(OR_TRAN_IPV4, off, BPF_H, v); +} + +static struct block * +gen_portatom6(off, v) + int off; + bpf_int32 v; +{ + return gen_cmp(OR_TRAN_IPV6, off, BPF_H, v); +} + +struct block * +gen_portop(port, proto, dir) + int port, proto, dir; +{ + struct block *b0, *b1, *tmp; + + /* ip proto 'proto' and not a fragment other than the first fragment */ + tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto); + b0 = gen_ipfrag(); + gen_and(tmp, b0); + + switch (dir) { + case Q_SRC: + b1 = gen_portatom(0, (bpf_int32)port); + break; + + case Q_DST: + b1 = gen_portatom(2, (bpf_int32)port); + break; + + case Q_OR: + case Q_DEFAULT: + tmp = gen_portatom(0, (bpf_int32)port); + b1 = gen_portatom(2, (bpf_int32)port); + gen_or(tmp, b1); + break; + + case Q_AND: + tmp = gen_portatom(0, (bpf_int32)port); + b1 = gen_portatom(2, (bpf_int32)port); + gen_and(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + + return b1; +} + +static struct block * +gen_port(port, ip_proto, dir) + int port; + int ip_proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* + * ether proto ip + * + * For FDDI, RFC 1188 says that SNAP encapsulation is used, + * not LLC encapsulation with LLCSAP_IP. + * + * For IEEE 802 networks - which includes 802.5 token ring + * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 + * says that SNAP encapsulation is used, not LLC encapsulation + * with LLCSAP_IP. + * + * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and + * RFC 2225 say that SNAP encapsulation is used, not LLC + * encapsulation with LLCSAP_IP. + * + * So we always check for ETHERTYPE_IP. + */ + b0 = gen_linktype(ETHERTYPE_IP); + + switch (ip_proto) { + case IPPROTO_UDP: + case IPPROTO_TCP: + case IPPROTO_SCTP: + b1 = gen_portop(port, ip_proto, dir); + break; + + case PROTO_UNDEF: + tmp = gen_portop(port, IPPROTO_TCP, dir); + b1 = gen_portop(port, IPPROTO_UDP, dir); + gen_or(tmp, b1); + tmp = gen_portop(port, IPPROTO_SCTP, dir); + gen_or(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + return b1; +} + +struct block * +gen_portop6(port, proto, dir) + int port, proto, dir; +{ + struct block *b0, *b1, *tmp; + + /* ip6 proto 'proto' */ + /* XXX - catch the first fragment of a fragmented packet? */ + b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto); + + switch (dir) { + case Q_SRC: + b1 = gen_portatom6(0, (bpf_int32)port); + break; + + case Q_DST: + b1 = gen_portatom6(2, (bpf_int32)port); + break; + + case Q_OR: + case Q_DEFAULT: + tmp = gen_portatom6(0, (bpf_int32)port); + b1 = gen_portatom6(2, (bpf_int32)port); + gen_or(tmp, b1); + break; + + case Q_AND: + tmp = gen_portatom6(0, (bpf_int32)port); + b1 = gen_portatom6(2, (bpf_int32)port); + gen_and(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + + return b1; +} + +static struct block * +gen_port6(port, ip_proto, dir) + int port; + int ip_proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* link proto ip6 */ + b0 = gen_linktype(ETHERTYPE_IPV6); + + switch (ip_proto) { + case IPPROTO_UDP: + case IPPROTO_TCP: + case IPPROTO_SCTP: + b1 = gen_portop6(port, ip_proto, dir); + break; + + case PROTO_UNDEF: + tmp = gen_portop6(port, IPPROTO_TCP, dir); + b1 = gen_portop6(port, IPPROTO_UDP, dir); + gen_or(tmp, b1); + tmp = gen_portop6(port, IPPROTO_SCTP, dir); + gen_or(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + return b1; +} + +/* gen_portrange code */ +static struct block * +gen_portrangeatom(off, v1, v2) + int off; + bpf_int32 v1, v2; +{ + struct block *b1, *b2; + + if (v1 > v2) { + /* + * Reverse the order of the ports, so v1 is the lower one. + */ + bpf_int32 vtemp; + + vtemp = v1; + v1 = v2; + v2 = vtemp; + } + + b1 = gen_cmp_ge(OR_TRAN_IPV4, off, BPF_H, v1); + b2 = gen_cmp_le(OR_TRAN_IPV4, off, BPF_H, v2); + + gen_and(b1, b2); + + return b2; +} + +struct block * +gen_portrangeop(port1, port2, proto, dir) + int port1, port2; + int proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* ip proto 'proto' and not a fragment other than the first fragment */ + tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto); + b0 = gen_ipfrag(); + gen_and(tmp, b0); + + switch (dir) { + case Q_SRC: + b1 = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2); + break; + + case Q_DST: + b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2); + break; + + case Q_OR: + case Q_DEFAULT: + tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2); + b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2); + gen_or(tmp, b1); + break; + + case Q_AND: + tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2); + b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2); + gen_and(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + + return b1; +} + +static struct block * +gen_portrange(port1, port2, ip_proto, dir) + int port1, port2; + int ip_proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* link proto ip */ + b0 = gen_linktype(ETHERTYPE_IP); + + switch (ip_proto) { + case IPPROTO_UDP: + case IPPROTO_TCP: + case IPPROTO_SCTP: + b1 = gen_portrangeop(port1, port2, ip_proto, dir); + break; + + case PROTO_UNDEF: + tmp = gen_portrangeop(port1, port2, IPPROTO_TCP, dir); + b1 = gen_portrangeop(port1, port2, IPPROTO_UDP, dir); + gen_or(tmp, b1); + tmp = gen_portrangeop(port1, port2, IPPROTO_SCTP, dir); + gen_or(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + return b1; +} + +static struct block * +gen_portrangeatom6(off, v1, v2) + int off; + bpf_int32 v1, v2; +{ + struct block *b1, *b2; + + if (v1 > v2) { + /* + * Reverse the order of the ports, so v1 is the lower one. + */ + bpf_int32 vtemp; + + vtemp = v1; + v1 = v2; + v2 = vtemp; + } + + b1 = gen_cmp_ge(OR_TRAN_IPV6, off, BPF_H, v1); + b2 = gen_cmp_le(OR_TRAN_IPV6, off, BPF_H, v2); + + gen_and(b1, b2); + + return b2; +} + +struct block * +gen_portrangeop6(port1, port2, proto, dir) + int port1, port2; + int proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* ip6 proto 'proto' */ + /* XXX - catch the first fragment of a fragmented packet? */ + b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto); + + switch (dir) { + case Q_SRC: + b1 = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2); + break; + + case Q_DST: + b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2); + break; + + case Q_OR: + case Q_DEFAULT: + tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2); + b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2); + gen_or(tmp, b1); + break; + + case Q_AND: + tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2); + b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2); + gen_and(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + + return b1; +} + +static struct block * +gen_portrange6(port1, port2, ip_proto, dir) + int port1, port2; + int ip_proto; + int dir; +{ + struct block *b0, *b1, *tmp; + + /* link proto ip6 */ + b0 = gen_linktype(ETHERTYPE_IPV6); + + switch (ip_proto) { + case IPPROTO_UDP: + case IPPROTO_TCP: + case IPPROTO_SCTP: + b1 = gen_portrangeop6(port1, port2, ip_proto, dir); + break; + + case PROTO_UNDEF: + tmp = gen_portrangeop6(port1, port2, IPPROTO_TCP, dir); + b1 = gen_portrangeop6(port1, port2, IPPROTO_UDP, dir); + gen_or(tmp, b1); + tmp = gen_portrangeop6(port1, port2, IPPROTO_SCTP, dir); + gen_or(tmp, b1); + break; + + default: + abort(); + } + gen_and(b0, b1); + return b1; +} + +static int +lookup_proto(name, proto) + register const char *name; + register int proto; +{ + register int v; + + switch (proto) { + + case Q_DEFAULT: + case Q_IP: + case Q_IPV6: + v = pcap_nametoproto(name); + if (v == PROTO_UNDEF) + bpf_error("unknown ip proto '%s'", name); + break; + + case Q_LINK: + /* XXX should look up h/w protocol type based on linktype */ + v = pcap_nametoeproto(name); + if (v == PROTO_UNDEF) { + v = pcap_nametollc(name); + if (v == PROTO_UNDEF) + bpf_error("unknown ether proto '%s'", name); + } + break; + + case Q_ISO: + if (strcmp(name, "esis") == 0) + v = ISO9542_ESIS; + else if (strcmp(name, "isis") == 0) + v = ISO10589_ISIS; + else if (strcmp(name, "clnp") == 0) + v = ISO8473_CLNP; + else + bpf_error("unknown osi proto '%s'", name); + break; + + default: + v = PROTO_UNDEF; + break; + } + return v; +} + +#if 0 +struct stmt * +gen_joinsp(s, n) + struct stmt **s; + int n; +{ + return NULL; +} +#endif + +static struct block * +gen_protochain(v, proto, dir) + int v; + int proto; + int dir; +{ +#ifdef NO_PROTOCHAIN + return gen_proto(v, proto, dir); +#else + struct block *b0, *b; + struct slist *s[100]; + int fix2, fix3, fix4, fix5; + int ahcheck, again, end; + int i, max; + int reg2 = alloc_reg(); + + memset(s, 0, sizeof(s)); + fix2 = fix3 = fix4 = fix5 = 0; + + switch (proto) { + case Q_IP: + case Q_IPV6: + break; + case Q_DEFAULT: + b0 = gen_protochain(v, Q_IP, dir); + b = gen_protochain(v, Q_IPV6, dir); + gen_or(b0, b); + return b; + default: + bpf_error("bad protocol applied for 'protochain'"); + /*NOTREACHED*/ + } + + /* + * We don't handle variable-length prefixes before the link-layer + * header, or variable-length link-layer headers, here yet. + * We might want to add BPF instructions to do the protochain + * work, to simplify that and, on platforms that have a BPF + * interpreter with the new instructions, let the filtering + * be done in the kernel. (We already require a modified BPF + * engine to do the protochain stuff, to support backward + * branches, and backward branch support is unlikely to appear + * in kernel BPF engines.) + */ + switch (linktype) { + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + bpf_error("'protochain' not supported with 802.11"); + } + + no_optimize = 1; /*this code is not compatible with optimzer yet */ + + /* + * s[0] is a dummy entry to protect other BPF insn from damage + * by s[fix] = foo with uninitialized variable "fix". It is somewhat + * hard to find interdependency made by jump table fixup. + */ + i = 0; + s[i] = new_stmt(0); /*dummy*/ + i++; + + switch (proto) { + case Q_IP: + b0 = gen_linktype(ETHERTYPE_IP); + + /* A = ip->ip_p */ + s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B); + s[i]->s.k = off_macpl + off_nl + 9; + i++; + /* X = ip->ip_hl << 2 */ + s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B); + s[i]->s.k = off_macpl + off_nl; + i++; + break; + + case Q_IPV6: + b0 = gen_linktype(ETHERTYPE_IPV6); + + /* A = ip6->ip_nxt */ + s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B); + s[i]->s.k = off_macpl + off_nl + 6; + i++; + /* X = sizeof(struct ip6_hdr) */ + s[i] = new_stmt(BPF_LDX|BPF_IMM); + s[i]->s.k = 40; + i++; + break; + + default: + bpf_error("unsupported proto to gen_protochain"); + /*NOTREACHED*/ + } + + /* again: if (A == v) goto end; else fall through; */ + again = i; + s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.k = v; + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*update in next stmt*/ + fix5 = i; + i++; + +#ifndef IPPROTO_NONE +#define IPPROTO_NONE 59 +#endif + /* if (A == IPPROTO_NONE) goto end */ + s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*update in next stmt*/ + s[i]->s.k = IPPROTO_NONE; + s[fix5]->s.jf = s[i]; + fix2 = i; + i++; + + if (proto == Q_IPV6) { + int v6start, v6end, v6advance, j; + + v6start = i; + /* if (A == IPPROTO_HOPOPTS) goto v6advance */ + s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*update in next stmt*/ + s[i]->s.k = IPPROTO_HOPOPTS; + s[fix2]->s.jf = s[i]; + i++; + /* if (A == IPPROTO_DSTOPTS) goto v6advance */ + s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*update in next stmt*/ + s[i]->s.k = IPPROTO_DSTOPTS; + i++; + /* if (A == IPPROTO_ROUTING) goto v6advance */ + s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*update in next stmt*/ + s[i]->s.k = IPPROTO_ROUTING; + i++; + /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */ + s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*later*/ + s[i]->s.k = IPPROTO_FRAGMENT; + fix3 = i; + v6end = i; + i++; + + /* v6advance: */ + v6advance = i; + + /* + * in short, + * A = P[X + packet head]; + * X = X + (P[X + packet head + 1] + 1) * 8; + */ + /* A = P[X + packet head] */ + s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); + s[i]->s.k = off_macpl + off_nl; + i++; + /* MEM[reg2] = A */ + s[i] = new_stmt(BPF_ST); + s[i]->s.k = reg2; + i++; + /* A = P[X + packet head + 1]; */ + s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); + s[i]->s.k = off_macpl + off_nl + 1; + i++; + /* A += 1 */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s[i]->s.k = 1; + i++; + /* A *= 8 */ + s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K); + s[i]->s.k = 8; + i++; + /* A += X */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_X); + s[i]->s.k = 0; + i++; + /* X = A; */ + s[i] = new_stmt(BPF_MISC|BPF_TAX); + i++; + /* A = MEM[reg2] */ + s[i] = new_stmt(BPF_LD|BPF_MEM); + s[i]->s.k = reg2; + i++; + + /* goto again; (must use BPF_JA for backward jump) */ + s[i] = new_stmt(BPF_JMP|BPF_JA); + s[i]->s.k = again - i - 1; + s[i - 1]->s.jf = s[i]; + i++; + + /* fixup */ + for (j = v6start; j <= v6end; j++) + s[j]->s.jt = s[v6advance]; + } else { + /* nop */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s[i]->s.k = 0; + s[fix2]->s.jf = s[i]; + i++; + } + + /* ahcheck: */ + ahcheck = i; + /* if (A == IPPROTO_AH) then fall through; else goto end; */ + s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); + s[i]->s.jt = NULL; /*later*/ + s[i]->s.jf = NULL; /*later*/ + s[i]->s.k = IPPROTO_AH; + if (fix3) + s[fix3]->s.jf = s[ahcheck]; + fix4 = i; + i++; + + /* + * in short, + * A = P[X]; + * X = X + (P[X + 1] + 2) * 4; + */ + /* A = X */ + s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA); + i++; + /* A = P[X + packet head]; */ + s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); + s[i]->s.k = off_macpl + off_nl; + i++; + /* MEM[reg2] = A */ + s[i] = new_stmt(BPF_ST); + s[i]->s.k = reg2; + i++; + /* A = X */ + s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA); + i++; + /* A += 1 */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s[i]->s.k = 1; + i++; + /* X = A */ + s[i] = new_stmt(BPF_MISC|BPF_TAX); + i++; + /* A = P[X + packet head] */ + s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); + s[i]->s.k = off_macpl + off_nl; + i++; + /* A += 2 */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s[i]->s.k = 2; + i++; + /* A *= 4 */ + s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K); + s[i]->s.k = 4; + i++; + /* X = A; */ + s[i] = new_stmt(BPF_MISC|BPF_TAX); + i++; + /* A = MEM[reg2] */ + s[i] = new_stmt(BPF_LD|BPF_MEM); + s[i]->s.k = reg2; + i++; + + /* goto again; (must use BPF_JA for backward jump) */ + s[i] = new_stmt(BPF_JMP|BPF_JA); + s[i]->s.k = again - i - 1; + i++; + + /* end: nop */ + end = i; + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); + s[i]->s.k = 0; + s[fix2]->s.jt = s[end]; + s[fix4]->s.jf = s[end]; + s[fix5]->s.jt = s[end]; + i++; + + /* + * make slist chain + */ + max = i; + for (i = 0; i < max - 1; i++) + s[i]->next = s[i + 1]; + s[max - 1]->next = NULL; + + /* + * emit final check + */ + b = new_block(JMP(BPF_JEQ)); + b->stmts = s[1]; /*remember, s[0] is dummy*/ + b->s.k = v; + + free_reg(reg2); + + gen_and(b0, b); + return b; +#endif +} + +static struct block * +gen_check_802_11_data_frame() +{ + struct slist *s; + struct block *b0, *b1; + + /* + * A data frame has the 0x08 bit (b3) in the frame control field set + * and the 0x04 bit (b2) clear. + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b0 = new_block(JMP(BPF_JSET)); + b0->s.k = 0x08; + b0->stmts = s; + + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x04; + b1->stmts = s; + gen_not(b1); + + gen_and(b1, b0); + + return b0; +} + +/* + * Generate code that checks whether the packet is a packet for protocol + * <proto> and whether the type field in that protocol's header has + * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an + * IP packet and checks the protocol number in the IP header against <v>. + * + * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks + * against Q_IP and Q_IPV6. + */ +static struct block * +gen_proto(v, proto, dir) + int v; + int proto; + int dir; +{ + struct block *b0, *b1; +#ifndef CHASE_CHAIN + struct block *b2; +#endif + + if (dir != Q_DEFAULT) + bpf_error("direction applied to 'proto'"); + + switch (proto) { + case Q_DEFAULT: + b0 = gen_proto(v, Q_IP, dir); + b1 = gen_proto(v, Q_IPV6, dir); + gen_or(b0, b1); + return b1; + + case Q_IP: + /* + * For FDDI, RFC 1188 says that SNAP encapsulation is used, + * not LLC encapsulation with LLCSAP_IP. + * + * For IEEE 802 networks - which includes 802.5 token ring + * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 + * says that SNAP encapsulation is used, not LLC encapsulation + * with LLCSAP_IP. + * + * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and + * RFC 2225 say that SNAP encapsulation is used, not LLC + * encapsulation with LLCSAP_IP. + * + * So we always check for ETHERTYPE_IP. + */ + b0 = gen_linktype(ETHERTYPE_IP); +#ifndef CHASE_CHAIN + b1 = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)v); +#else + b1 = gen_protochain(v, Q_IP); +#endif + gen_and(b0, b1); + return b1; + + case Q_ISO: + switch (linktype) { + + case DLT_FRELAY: + /* + * Frame Relay packets typically have an OSI + * NLPID at the beginning; "gen_linktype(LLCSAP_ISONS)" + * generates code to check for all the OSI + * NLPIDs, so calling it and then adding a check + * for the particular NLPID for which we're + * looking is bogus, as we can just check for + * the NLPID. + * + * What we check for is the NLPID and a frame + * control field value of UI, i.e. 0x03 followed + * by the NLPID. + * + * XXX - assumes a 2-byte Frame Relay header with + * DLCI and flags. What if the address is longer? + * + * XXX - what about SNAP-encapsulated frames? + */ + return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | v); + /*NOTREACHED*/ + break; + + case DLT_C_HDLC: + /* + * Cisco uses an Ethertype lookalike - for OSI, + * it's 0xfefe. + */ + b0 = gen_linktype(LLCSAP_ISONS<<8 | LLCSAP_ISONS); + /* OSI in C-HDLC is stuffed with a fudge byte */ + b1 = gen_cmp(OR_NET_NOSNAP, 1, BPF_B, (long)v); + gen_and(b0, b1); + return b1; + + default: + b0 = gen_linktype(LLCSAP_ISONS); + b1 = gen_cmp(OR_NET_NOSNAP, 0, BPF_B, (long)v); + gen_and(b0, b1); + return b1; + } + + case Q_ISIS: + b0 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT); + /* + * 4 is the offset of the PDU type relative to the IS-IS + * header. + */ + b1 = gen_cmp(OR_NET_NOSNAP, 4, BPF_B, (long)v); + gen_and(b0, b1); + return b1; + + case Q_ARP: + bpf_error("arp does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_RARP: + bpf_error("rarp does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_ATALK: + bpf_error("atalk encapsulation is not specifiable"); + /* NOTREACHED */ + + case Q_DECNET: + bpf_error("decnet encapsulation is not specifiable"); + /* NOTREACHED */ + + case Q_SCA: + bpf_error("sca does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_LAT: + bpf_error("lat does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_MOPRC: + bpf_error("moprc does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_MOPDL: + bpf_error("mopdl does not encapsulate another protocol"); + /* NOTREACHED */ + + case Q_LINK: + return gen_linktype(v); + + case Q_UDP: + bpf_error("'udp proto' is bogus"); + /* NOTREACHED */ + + case Q_TCP: + bpf_error("'tcp proto' is bogus"); + /* NOTREACHED */ + + case Q_SCTP: + bpf_error("'sctp proto' is bogus"); + /* NOTREACHED */ + + case Q_ICMP: + bpf_error("'icmp proto' is bogus"); + /* NOTREACHED */ + + case Q_IGMP: + bpf_error("'igmp proto' is bogus"); + /* NOTREACHED */ + + case Q_IGRP: + bpf_error("'igrp proto' is bogus"); + /* NOTREACHED */ + + case Q_PIM: + bpf_error("'pim proto' is bogus"); + /* NOTREACHED */ + + case Q_VRRP: + bpf_error("'vrrp proto' is bogus"); + /* NOTREACHED */ + + case Q_CARP: + bpf_error("'carp proto' is bogus"); + /* NOTREACHED */ + + case Q_IPV6: + b0 = gen_linktype(ETHERTYPE_IPV6); +#ifndef CHASE_CHAIN + /* + * Also check for a fragment header before the final + * header. + */ + b2 = gen_cmp(OR_NET, 6, BPF_B, IPPROTO_FRAGMENT); + b1 = gen_cmp(OR_NET, 40, BPF_B, (bpf_int32)v); + gen_and(b2, b1); + b2 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)v); + gen_or(b2, b1); +#else + b1 = gen_protochain(v, Q_IPV6); +#endif + gen_and(b0, b1); + return b1; + + case Q_ICMPV6: + bpf_error("'icmp6 proto' is bogus"); + + case Q_AH: + bpf_error("'ah proto' is bogus"); + + case Q_ESP: + bpf_error("'ah proto' is bogus"); + + case Q_STP: + bpf_error("'stp proto' is bogus"); + + case Q_IPX: + bpf_error("'ipx proto' is bogus"); + + case Q_NETBEUI: + bpf_error("'netbeui proto' is bogus"); + + case Q_RADIO: + bpf_error("'radio proto' is bogus"); + + default: + abort(); + /* NOTREACHED */ + } + /* NOTREACHED */ +} + +struct block * +gen_scode(name, q) + register const char *name; + struct qual q; +{ + int proto = q.proto; + int dir = q.dir; + int tproto; + u_char *eaddr; + bpf_u_int32 mask, addr; +#ifndef INET6 + bpf_u_int32 **alist; +#else + int tproto6; + struct sockaddr_in *sin4; + struct sockaddr_in6 *sin6; + struct addrinfo *res, *res0; + struct in6_addr mask128; +#endif /*INET6*/ + struct block *b, *tmp; + int port, real_proto; + int port1, port2; + + switch (q.addr) { + + case Q_NET: + addr = pcap_nametonetaddr(name); + if (addr == 0) + bpf_error("unknown network '%s'", name); + /* Left justify network addr and calculate its network mask */ + mask = 0xffffffff; + while (addr && (addr & 0xff000000) == 0) { + addr <<= 8; + mask <<= 8; + } + return gen_host(addr, mask, proto, dir, q.addr); + + case Q_DEFAULT: + case Q_HOST: + if (proto == Q_LINK) { + switch (linktype) { + + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown ether host '%s'", name); + b = gen_ehostop(eaddr, dir); + free(eaddr); + return b; + + case DLT_FDDI: + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown FDDI host '%s'", name); + b = gen_fhostop(eaddr, dir); + free(eaddr); + return b; + + case DLT_IEEE802: + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown token ring host '%s'", name); + b = gen_thostop(eaddr, dir); + free(eaddr); + return b; + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown 802.11 host '%s'", name); + b = gen_wlanhostop(eaddr, dir); + free(eaddr); + return b; + + case DLT_IP_OVER_FC: + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown Fibre Channel host '%s'", name); + b = gen_ipfchostop(eaddr, dir); + free(eaddr); + return b; + + case DLT_SUNATM: + if (!is_lane) + break; + + /* + * Check that the packet doesn't begin + * with an LE Control marker. (We've + * already generated a test for LANE.) + */ + tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, + BPF_H, 0xFF00); + gen_not(tmp); + + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error( + "unknown ether host '%s'", name); + b = gen_ehostop(eaddr, dir); + gen_and(tmp, b); + free(eaddr); + return b; + } + + bpf_error("only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name"); + } else if (proto == Q_DECNET) { + unsigned short dn_addr = __pcap_nametodnaddr(name); + /* + * I don't think DECNET hosts can be multihomed, so + * there is no need to build up a list of addresses + */ + return (gen_host(dn_addr, 0, proto, dir, q.addr)); + } else { +#ifndef INET6 + alist = pcap_nametoaddr(name); + if (alist == NULL || *alist == NULL) + bpf_error("unknown host '%s'", name); + tproto = proto; + if (off_linktype == (u_int)-1 && tproto == Q_DEFAULT) + tproto = Q_IP; + b = gen_host(**alist++, 0xffffffff, tproto, dir, q.addr); + while (*alist) { + tmp = gen_host(**alist++, 0xffffffff, + tproto, dir, q.addr); + gen_or(b, tmp); + b = tmp; + } + return b; +#else + memset(&mask128, 0xff, sizeof(mask128)); + res0 = res = pcap_nametoaddrinfo(name); + if (res == NULL) + bpf_error("unknown host '%s'", name); + ai = res; + b = tmp = NULL; + tproto = tproto6 = proto; + if (off_linktype == -1 && tproto == Q_DEFAULT) { + tproto = Q_IP; + tproto6 = Q_IPV6; + } + for (res = res0; res; res = res->ai_next) { + switch (res->ai_family) { + case AF_INET: + if (tproto == Q_IPV6) + continue; + + sin4 = (struct sockaddr_in *) + res->ai_addr; + tmp = gen_host(ntohl(sin4->sin_addr.s_addr), + 0xffffffff, tproto, dir, q.addr); + break; + case AF_INET6: + if (tproto6 == Q_IP) + continue; + + sin6 = (struct sockaddr_in6 *) + res->ai_addr; + tmp = gen_host6(&sin6->sin6_addr, + &mask128, tproto6, dir, q.addr); + break; + default: + continue; + } + if (b) + gen_or(b, tmp); + b = tmp; + } + ai = NULL; + freeaddrinfo(res0); + if (b == NULL) { + bpf_error("unknown host '%s'%s", name, + (proto == Q_DEFAULT) + ? "" + : " for specified address family"); + } + return b; +#endif /*INET6*/ + } + + case Q_PORT: + if (proto != Q_DEFAULT && + proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) + bpf_error("illegal qualifier of 'port'"); + if (pcap_nametoport(name, &port, &real_proto) == 0) + bpf_error("unknown port '%s'", name); + if (proto == Q_UDP) { + if (real_proto == IPPROTO_TCP) + bpf_error("port '%s' is tcp", name); + else if (real_proto == IPPROTO_SCTP) + bpf_error("port '%s' is sctp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_UDP; + } + if (proto == Q_TCP) { + if (real_proto == IPPROTO_UDP) + bpf_error("port '%s' is udp", name); + + else if (real_proto == IPPROTO_SCTP) + bpf_error("port '%s' is sctp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_TCP; + } + if (proto == Q_SCTP) { + if (real_proto == IPPROTO_UDP) + bpf_error("port '%s' is udp", name); + + else if (real_proto == IPPROTO_TCP) + bpf_error("port '%s' is tcp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_SCTP; + } + if (port < 0) + bpf_error("illegal port number %d < 0", port); + if (port > 65535) + bpf_error("illegal port number %d > 65535", port); + b = gen_port(port, real_proto, dir); + gen_or(gen_port6(port, real_proto, dir), b); + return b; + + case Q_PORTRANGE: + if (proto != Q_DEFAULT && + proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) + bpf_error("illegal qualifier of 'portrange'"); + if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0) + bpf_error("unknown port in range '%s'", name); + if (proto == Q_UDP) { + if (real_proto == IPPROTO_TCP) + bpf_error("port in range '%s' is tcp", name); + else if (real_proto == IPPROTO_SCTP) + bpf_error("port in range '%s' is sctp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_UDP; + } + if (proto == Q_TCP) { + if (real_proto == IPPROTO_UDP) + bpf_error("port in range '%s' is udp", name); + else if (real_proto == IPPROTO_SCTP) + bpf_error("port in range '%s' is sctp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_TCP; + } + if (proto == Q_SCTP) { + if (real_proto == IPPROTO_UDP) + bpf_error("port in range '%s' is udp", name); + else if (real_proto == IPPROTO_TCP) + bpf_error("port in range '%s' is tcp", name); + else + /* override PROTO_UNDEF */ + real_proto = IPPROTO_SCTP; + } + if (port1 < 0) + bpf_error("illegal port number %d < 0", port1); + if (port1 > 65535) + bpf_error("illegal port number %d > 65535", port1); + if (port2 < 0) + bpf_error("illegal port number %d < 0", port2); + if (port2 > 65535) + bpf_error("illegal port number %d > 65535", port2); + + b = gen_portrange(port1, port2, real_proto, dir); + gen_or(gen_portrange6(port1, port2, real_proto, dir), b); + return b; + + case Q_GATEWAY: +#ifndef INET6 + eaddr = pcap_ether_hostton(name); + if (eaddr == NULL) + bpf_error("unknown ether host: %s", name); + + alist = pcap_nametoaddr(name); + if (alist == NULL || *alist == NULL) + bpf_error("unknown host '%s'", name); + b = gen_gateway(eaddr, alist, proto, dir); + free(eaddr); + return b; +#else + bpf_error("'gateway' not supported in this configuration"); +#endif /*INET6*/ + + case Q_PROTO: + real_proto = lookup_proto(name, proto); + if (real_proto >= 0) + return gen_proto(real_proto, proto, dir); + else + bpf_error("unknown protocol: %s", name); + + case Q_PROTOCHAIN: + real_proto = lookup_proto(name, proto); + if (real_proto >= 0) + return gen_protochain(real_proto, proto, dir); + else + bpf_error("unknown protocol: %s", name); + + case Q_UNDEF: + syntax(); + /* NOTREACHED */ + } + abort(); + /* NOTREACHED */ +} + +struct block * +gen_mcode(s1, s2, masklen, q) + register const char *s1, *s2; + register int masklen; + struct qual q; +{ + register int nlen, mlen; + bpf_u_int32 n, m; + + nlen = __pcap_atoin(s1, &n); + /* Promote short ipaddr */ + n <<= 32 - nlen; + + if (s2 != NULL) { + mlen = __pcap_atoin(s2, &m); + /* Promote short ipaddr */ + m <<= 32 - mlen; + if ((n & ~m) != 0) + bpf_error("non-network bits set in \"%s mask %s\"", + s1, s2); + } else { + /* Convert mask len to mask */ + if (masklen > 32) + bpf_error("mask length must be <= 32"); + if (masklen == 0) { + /* + * X << 32 is not guaranteed by C to be 0; it's + * undefined. + */ + m = 0; + } else + m = 0xffffffff << (32 - masklen); + if ((n & ~m) != 0) + bpf_error("non-network bits set in \"%s/%d\"", + s1, masklen); + } + + switch (q.addr) { + + case Q_NET: + return gen_host(n, m, q.proto, q.dir, q.addr); + + default: + bpf_error("Mask syntax for networks only"); + /* NOTREACHED */ + } + /* NOTREACHED */ + return NULL; +} + +struct block * +gen_ncode(s, v, q) + register const char *s; + bpf_u_int32 v; + struct qual q; +{ + bpf_u_int32 mask; + int proto = q.proto; + int dir = q.dir; + register int vlen; + + if (s == NULL) + vlen = 32; + else if (q.proto == Q_DECNET) + vlen = __pcap_atodn(s, &v); + else + vlen = __pcap_atoin(s, &v); + + switch (q.addr) { + + case Q_DEFAULT: + case Q_HOST: + case Q_NET: + if (proto == Q_DECNET) + return gen_host(v, 0, proto, dir, q.addr); + else if (proto == Q_LINK) { + bpf_error("illegal link layer address"); + } else { + mask = 0xffffffff; + if (s == NULL && q.addr == Q_NET) { + /* Promote short net number */ + while (v && (v & 0xff000000) == 0) { + v <<= 8; + mask <<= 8; + } + } else { + /* Promote short ipaddr */ + v <<= 32 - vlen; + mask <<= 32 - vlen; + } + return gen_host(v, mask, proto, dir, q.addr); + } + + case Q_PORT: + if (proto == Q_UDP) + proto = IPPROTO_UDP; + else if (proto == Q_TCP) + proto = IPPROTO_TCP; + else if (proto == Q_SCTP) + proto = IPPROTO_SCTP; + else if (proto == Q_DEFAULT) + proto = PROTO_UNDEF; + else + bpf_error("illegal qualifier of 'port'"); + + if (v > 65535) + bpf_error("illegal port number %u > 65535", v); + + { + struct block *b; + b = gen_port((int)v, proto, dir); + gen_or(gen_port6((int)v, proto, dir), b); + return b; + } + + case Q_PORTRANGE: + if (proto == Q_UDP) + proto = IPPROTO_UDP; + else if (proto == Q_TCP) + proto = IPPROTO_TCP; + else if (proto == Q_SCTP) + proto = IPPROTO_SCTP; + else if (proto == Q_DEFAULT) + proto = PROTO_UNDEF; + else + bpf_error("illegal qualifier of 'portrange'"); + + if (v > 65535) + bpf_error("illegal port number %u > 65535", v); + + { + struct block *b; + b = gen_portrange((int)v, (int)v, proto, dir); + gen_or(gen_portrange6((int)v, (int)v, proto, dir), b); + return b; + } + + case Q_GATEWAY: + bpf_error("'gateway' requires a name"); + /* NOTREACHED */ + + case Q_PROTO: + return gen_proto((int)v, proto, dir); + + case Q_PROTOCHAIN: + return gen_protochain((int)v, proto, dir); + + case Q_UNDEF: + syntax(); + /* NOTREACHED */ + + default: + abort(); + /* NOTREACHED */ + } + /* NOTREACHED */ +} + +#ifdef INET6 +struct block * +gen_mcode6(s1, s2, masklen, q) + register const char *s1, *s2; + register int masklen; + struct qual q; +{ + struct addrinfo *res; + struct in6_addr *addr; + struct in6_addr mask; + struct block *b; + u_int32_t *a, *m; + + if (s2) + bpf_error("no mask %s supported", s2); + + res = pcap_nametoaddrinfo(s1); + if (!res) + bpf_error("invalid ip6 address %s", s1); + ai = res; + if (res->ai_next) + bpf_error("%s resolved to multiple address", s1); + addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr; + + if (sizeof(mask) * 8 < masklen) + bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8)); + memset(&mask, 0, sizeof(mask)); + memset(&mask, 0xff, masklen / 8); + if (masklen % 8) { + mask.s6_addr[masklen / 8] = + (0xff << (8 - masklen % 8)) & 0xff; + } + + a = (u_int32_t *)addr; + m = (u_int32_t *)&mask; + if ((a[0] & ~m[0]) || (a[1] & ~m[1]) + || (a[2] & ~m[2]) || (a[3] & ~m[3])) { + bpf_error("non-network bits set in \"%s/%d\"", s1, masklen); + } + + switch (q.addr) { + + case Q_DEFAULT: + case Q_HOST: + if (masklen != 128) + bpf_error("Mask syntax for networks only"); + /* FALLTHROUGH */ + + case Q_NET: + b = gen_host6(addr, &mask, q.proto, q.dir, q.addr); + ai = NULL; + freeaddrinfo(res); + return b; + + default: + bpf_error("invalid qualifier against IPv6 address"); + /* NOTREACHED */ + } + return NULL; +} +#endif /*INET6*/ + +struct block * +gen_ecode(eaddr, q) + register const u_char *eaddr; + struct qual q; +{ + struct block *b, *tmp; + + if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { + switch (linktype) { + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + return gen_ehostop(eaddr, (int)q.dir); + case DLT_FDDI: + return gen_fhostop(eaddr, (int)q.dir); + case DLT_IEEE802: + return gen_thostop(eaddr, (int)q.dir); + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + return gen_wlanhostop(eaddr, (int)q.dir); + case DLT_SUNATM: + if (is_lane) { + /* + * Check that the packet doesn't begin with an + * LE Control marker. (We've already generated + * a test for LANE.) + */ + tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, + 0xFF00); + gen_not(tmp); + + /* + * Now check the MAC address. + */ + b = gen_ehostop(eaddr, (int)q.dir); + gen_and(tmp, b); + return b; + } + break; + case DLT_IP_OVER_FC: + return gen_ipfchostop(eaddr, (int)q.dir); + default: + bpf_error("ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); + break; + } + } + bpf_error("ethernet address used in non-ether expression"); + /* NOTREACHED */ + return NULL; +} + +void +sappend(s0, s1) + struct slist *s0, *s1; +{ + /* + * This is definitely not the best way to do this, but the + * lists will rarely get long. + */ + while (s0->next) + s0 = s0->next; + s0->next = s1; +} + +static struct slist * +xfer_to_x(a) + struct arth *a; +{ + struct slist *s; + + s = new_stmt(BPF_LDX|BPF_MEM); + s->s.k = a->regno; + return s; +} + +static struct slist * +xfer_to_a(a) + struct arth *a; +{ + struct slist *s; + + s = new_stmt(BPF_LD|BPF_MEM); + s->s.k = a->regno; + return s; +} + +/* + * Modify "index" to use the value stored into its register as an + * offset relative to the beginning of the header for the protocol + * "proto", and allocate a register and put an item "size" bytes long + * (1, 2, or 4) at that offset into that register, making it the register + * for "index". + */ +struct arth * +gen_load(proto, inst, size) + int proto; + struct arth *inst; + int size; +{ + struct slist *s, *tmp; + struct block *b; + int regno = alloc_reg(); + + free_reg(inst->regno); + switch (size) { + + default: + bpf_error("data size must be 1, 2, or 4"); + + case 1: + size = BPF_B; + break; + + case 2: + size = BPF_H; + break; + + case 4: + size = BPF_W; + break; + } + switch (proto) { + default: + bpf_error("unsupported index operation"); + + case Q_RADIO: + /* + * The offset is relative to the beginning of the packet + * data, if we have a radio header. (If we don't, this + * is an error.) + */ + if (linktype != DLT_IEEE802_11_RADIO_AVS && + linktype != DLT_IEEE802_11_RADIO && + linktype != DLT_PRISM_HEADER) + bpf_error("radio information not present in capture"); + + /* + * Load into the X register the offset computed into the + * register specified by "index". + */ + s = xfer_to_x(inst); + + /* + * Load the item at that offset. + */ + tmp = new_stmt(BPF_LD|BPF_IND|size); + sappend(s, tmp); + sappend(inst->s, s); + break; + + case Q_LINK: + /* + * The offset is relative to the beginning of + * the link-layer header. + * + * XXX - what about ATM LANE? Should the index be + * relative to the beginning of the AAL5 frame, so + * that 0 refers to the beginning of the LE Control + * field, or relative to the beginning of the LAN + * frame, so that 0 refers, for Ethernet LANE, to + * the beginning of the destination address? + */ + s = gen_llprefixlen(); + + /* + * If "s" is non-null, it has code to arrange that the + * X register contains the length of the prefix preceding + * the link-layer header. Add to it the offset computed + * into the register specified by "index", and move that + * into the X register. Otherwise, just load into the X + * register the offset computed into the register specified + * by "index". + */ + if (s != NULL) { + sappend(s, xfer_to_a(inst)); + sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); + sappend(s, new_stmt(BPF_MISC|BPF_TAX)); + } else + s = xfer_to_x(inst); + + /* + * Load the item at the sum of the offset we've put in the + * X register and the offset of the start of the link + * layer header (which is 0 if the radio header is + * variable-length; that header length is what we put + * into the X register and then added to the index). + */ + tmp = new_stmt(BPF_LD|BPF_IND|size); + tmp->s.k = off_ll; + sappend(s, tmp); + sappend(inst->s, s); + break; + + case Q_IP: + case Q_ARP: + case Q_RARP: + case Q_ATALK: + case Q_DECNET: + case Q_SCA: + case Q_LAT: + case Q_MOPRC: + case Q_MOPDL: + case Q_IPV6: + /* + * The offset is relative to the beginning of + * the network-layer header. + * XXX - are there any cases where we want + * off_nl_nosnap? + */ + s = gen_off_macpl(); + + /* + * If "s" is non-null, it has code to arrange that the + * X register contains the offset of the MAC-layer + * payload. Add to it the offset computed into the + * register specified by "index", and move that into + * the X register. Otherwise, just load into the X + * register the offset computed into the register specified + * by "index". + */ + if (s != NULL) { + sappend(s, xfer_to_a(inst)); + sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); + sappend(s, new_stmt(BPF_MISC|BPF_TAX)); + } else + s = xfer_to_x(inst); + + /* + * Load the item at the sum of the offset we've put in the + * X register, the offset of the start of the network + * layer header from the beginning of the MAC-layer + * payload, and the purported offset of the start of the + * MAC-layer payload (which might be 0 if there's a + * variable-length prefix before the link-layer header + * or the link-layer header itself is variable-length; + * the variable-length offset of the start of the + * MAC-layer payload is what we put into the X register + * and then added to the index). + */ + tmp = new_stmt(BPF_LD|BPF_IND|size); + tmp->s.k = off_macpl + off_nl; + sappend(s, tmp); + sappend(inst->s, s); + + /* + * Do the computation only if the packet contains + * the protocol in question. + */ + b = gen_proto_abbrev(proto); + if (inst->b) + gen_and(inst->b, b); + inst->b = b; + break; + + case Q_SCTP: + case Q_TCP: + case Q_UDP: + case Q_ICMP: + case Q_IGMP: + case Q_IGRP: + case Q_PIM: + case Q_VRRP: + case Q_CARP: + /* + * The offset is relative to the beginning of + * the transport-layer header. + * + * Load the X register with the length of the IPv4 header + * (plus the offset of the link-layer header, if it's + * a variable-length header), in bytes. + * + * XXX - are there any cases where we want + * off_nl_nosnap? + * XXX - we should, if we're built with + * IPv6 support, generate code to load either + * IPv4, IPv6, or both, as appropriate. + */ + s = gen_loadx_iphdrlen(); + + /* + * The X register now contains the sum of the length + * of any variable-length header preceding the link-layer + * header, any variable-length link-layer header, and the + * length of the network-layer header. + * + * Load into the A register the offset relative to + * the beginning of the transport layer header, + * add the X register to that, move that to the + * X register, and load with an offset from the + * X register equal to the offset of the network + * layer header relative to the beginning of + * the MAC-layer payload plus the fixed-length + * portion of the offset of the MAC-layer payload + * from the beginning of the raw packet data. + */ + sappend(s, xfer_to_a(inst)); + sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); + sappend(s, new_stmt(BPF_MISC|BPF_TAX)); + sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size)); + tmp->s.k = off_macpl + off_nl; + sappend(inst->s, s); + + /* + * Do the computation only if the packet contains + * the protocol in question - which is true only + * if this is an IP datagram and is the first or + * only fragment of that datagram. + */ + gen_and(gen_proto_abbrev(proto), b = gen_ipfrag()); + if (inst->b) + gen_and(inst->b, b); + gen_and(gen_proto_abbrev(Q_IP), b); + inst->b = b; + break; + case Q_ICMPV6: + bpf_error("IPv6 upper-layer protocol is not supported by proto[x]"); + /*NOTREACHED*/ + } + inst->regno = regno; + s = new_stmt(BPF_ST); + s->s.k = regno; + sappend(inst->s, s); + + return inst; +} + +struct block * +gen_relation(code, a0, a1, reversed) + int code; + struct arth *a0, *a1; + int reversed; +{ + struct slist *s0, *s1, *s2; + struct block *b, *tmp; + + s0 = xfer_to_x(a1); + s1 = xfer_to_a(a0); + if (code == BPF_JEQ) { + s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X); + b = new_block(JMP(code)); + sappend(s1, s2); + } + else + b = new_block(BPF_JMP|code|BPF_X); + if (reversed) + gen_not(b); + + sappend(s0, s1); + sappend(a1->s, s0); + sappend(a0->s, a1->s); + + b->stmts = a0->s; + + free_reg(a0->regno); + free_reg(a1->regno); + + /* 'and' together protocol checks */ + if (a0->b) { + if (a1->b) { + gen_and(a0->b, tmp = a1->b); + } + else + tmp = a0->b; + } else + tmp = a1->b; + + if (tmp) + gen_and(tmp, b); + + return b; +} + +struct arth * +gen_loadlen() +{ + int regno = alloc_reg(); + struct arth *a = (struct arth *)newchunk(sizeof(*a)); + struct slist *s; + + s = new_stmt(BPF_LD|BPF_LEN); + s->next = new_stmt(BPF_ST); + s->next->s.k = regno; + a->s = s; + a->regno = regno; + + return a; +} + +struct arth * +gen_loadi(val) + int val; +{ + struct arth *a; + struct slist *s; + int reg; + + a = (struct arth *)newchunk(sizeof(*a)); + + reg = alloc_reg(); + + s = new_stmt(BPF_LD|BPF_IMM); + s->s.k = val; + s->next = new_stmt(BPF_ST); + s->next->s.k = reg; + a->s = s; + a->regno = reg; + + return a; +} + +struct arth * +gen_neg(a) + struct arth *a; +{ + struct slist *s; + + s = xfer_to_a(a); + sappend(a->s, s); + s = new_stmt(BPF_ALU|BPF_NEG); + s->s.k = 0; + sappend(a->s, s); + s = new_stmt(BPF_ST); + s->s.k = a->regno; + sappend(a->s, s); + + return a; +} + +struct arth * +gen_arth(code, a0, a1) + int code; + struct arth *a0, *a1; +{ + struct slist *s0, *s1, *s2; + + s0 = xfer_to_x(a1); + s1 = xfer_to_a(a0); + s2 = new_stmt(BPF_ALU|BPF_X|code); + + sappend(s1, s2); + sappend(s0, s1); + sappend(a1->s, s0); + sappend(a0->s, a1->s); + + free_reg(a0->regno); + free_reg(a1->regno); + + s0 = new_stmt(BPF_ST); + a0->regno = s0->s.k = alloc_reg(); + sappend(a0->s, s0); + + return a0; +} + +/* + * Here we handle simple allocation of the scratch registers. + * If too many registers are alloc'd, the allocator punts. + */ +static int regused[BPF_MEMWORDS]; +static int curreg; + +/* + * Initialize the table of used registers and the current register. + */ +static void +init_regs() +{ + curreg = 0; + memset(regused, 0, sizeof regused); +} + +/* + * Return the next free register. + */ +static int +alloc_reg() +{ + int n = BPF_MEMWORDS; + + while (--n >= 0) { + if (regused[curreg]) + curreg = (curreg + 1) % BPF_MEMWORDS; + else { + regused[curreg] = 1; + return curreg; + } + } + bpf_error("too many registers needed to evaluate expression"); + /* NOTREACHED */ + return 0; +} + +/* + * Return a register to the table so it can + * be used later. + */ +static void +free_reg(n) + int n; +{ + regused[n] = 0; +} + +static struct block * +gen_len(jmp, n) + int jmp, n; +{ + struct slist *s; + struct block *b; + + s = new_stmt(BPF_LD|BPF_LEN); + b = new_block(JMP(jmp)); + b->stmts = s; + b->s.k = n; + + return b; +} + +struct block * +gen_greater(n) + int n; +{ + return gen_len(BPF_JGE, n); +} + +/* + * Actually, this is less than or equal. + */ +struct block * +gen_less(n) + int n; +{ + struct block *b; + + b = gen_len(BPF_JGT, n); + gen_not(b); + + return b; +} + +/* + * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to + * the beginning of the link-layer header. + * XXX - that means you can't test values in the radiotap header, but + * as that header is difficult if not impossible to parse generally + * without a loop, that might not be a severe problem. A new keyword + * "radio" could be added for that, although what you'd really want + * would be a way of testing particular radio header values, which + * would generate code appropriate to the radio header in question. + */ +struct block * +gen_byteop(op, idx, val) + int op, idx, val; +{ + struct block *b; + struct slist *s; + + switch (op) { + default: + abort(); + + case '=': + return gen_cmp(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val); + + case '<': + b = gen_cmp_lt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val); + return b; + + case '>': + b = gen_cmp_gt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val); + return b; + + case '|': + s = new_stmt(BPF_ALU|BPF_OR|BPF_K); + break; + + case '&': + s = new_stmt(BPF_ALU|BPF_AND|BPF_K); + break; + } + s->s.k = val; + b = new_block(JMP(BPF_JEQ)); + b->stmts = s; + gen_not(b); + + return b; +} + +static u_char abroadcast[] = { 0x0 }; + +struct block * +gen_broadcast(proto) + int proto; +{ + bpf_u_int32 hostmask; + struct block *b0, *b1, *b2; + static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; + + switch (proto) { + + case Q_DEFAULT: + case Q_LINK: + switch (linktype) { + case DLT_ARCNET: + case DLT_ARCNET_LINUX: + return gen_ahostop(abroadcast, Q_DST); + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + return gen_ehostop(ebroadcast, Q_DST); + case DLT_FDDI: + return gen_fhostop(ebroadcast, Q_DST); + case DLT_IEEE802: + return gen_thostop(ebroadcast, Q_DST); + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + return gen_wlanhostop(ebroadcast, Q_DST); + case DLT_IP_OVER_FC: + return gen_ipfchostop(ebroadcast, Q_DST); + case DLT_SUNATM: + if (is_lane) { + /* + * Check that the packet doesn't begin with an + * LE Control marker. (We've already generated + * a test for LANE.) + */ + b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, + BPF_H, 0xFF00); + gen_not(b1); + + /* + * Now check the MAC address. + */ + b0 = gen_ehostop(ebroadcast, Q_DST); + gen_and(b1, b0); + return b0; + } + break; + default: + bpf_error("not a broadcast link"); + } + break; + + case Q_IP: + /* + * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff) + * as an indication that we don't know the netmask, and fail + * in that case. + */ + if (netmask == PCAP_NETMASK_UNKNOWN) + bpf_error("netmask not known, so 'ip broadcast' not supported"); + b0 = gen_linktype(ETHERTYPE_IP); + hostmask = ~netmask; + b1 = gen_mcmp(OR_NET, 16, BPF_W, (bpf_int32)0, hostmask); + b2 = gen_mcmp(OR_NET, 16, BPF_W, + (bpf_int32)(~0 & hostmask), hostmask); + gen_or(b1, b2); + gen_and(b0, b2); + return b2; + } + bpf_error("only link-layer/IP broadcast filters supported"); + /* NOTREACHED */ + return NULL; +} + +/* + * Generate code to test the low-order bit of a MAC address (that's + * the bottom bit of the *first* byte). + */ +static struct block * +gen_mac_multicast(offset) + int offset; +{ + register struct block *b0; + register struct slist *s; + + /* link[offset] & 1 != 0 */ + s = gen_load_a(OR_LINK, offset, BPF_B); + b0 = new_block(JMP(BPF_JSET)); + b0->s.k = 1; + b0->stmts = s; + return b0; +} + +struct block * +gen_multicast(proto) + int proto; +{ + register struct block *b0, *b1, *b2; + register struct slist *s; + + switch (proto) { + + case Q_DEFAULT: + case Q_LINK: + switch (linktype) { + case DLT_ARCNET: + case DLT_ARCNET_LINUX: + /* all ARCnet multicasts use the same address */ + return gen_ahostop(abroadcast, Q_DST); + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + /* ether[0] & 1 != 0 */ + return gen_mac_multicast(0); + case DLT_FDDI: + /* + * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX + * + * XXX - was that referring to bit-order issues? + */ + /* fddi[1] & 1 != 0 */ + return gen_mac_multicast(1); + case DLT_IEEE802: + /* tr[2] & 1 != 0 */ + return gen_mac_multicast(2); + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + case DLT_PPI: + /* + * Oh, yuk. + * + * For control frames, there is no DA. + * + * For management frames, DA is at an + * offset of 4 from the beginning of + * the packet. + * + * For data frames, DA is at an offset + * of 4 from the beginning of the packet + * if To DS is clear and at an offset of + * 16 from the beginning of the packet + * if To DS is set. + */ + + /* + * Generate the tests to be done for data frames. + * + * First, check for To DS set, i.e. "link[1] & 0x01". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x01; /* To DS */ + b1->stmts = s; + + /* + * If To DS is set, the DA is at 16. + */ + b0 = gen_mac_multicast(16); + gen_and(b1, b0); + + /* + * Now, check for To DS not set, i.e. check + * "!(link[1] & 0x01)". + */ + s = gen_load_a(OR_LINK, 1, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x01; /* To DS */ + b2->stmts = s; + gen_not(b2); + + /* + * If To DS is not set, the DA is at 4. + */ + b1 = gen_mac_multicast(4); + gen_and(b2, b1); + + /* + * Now OR together the last two checks. That gives + * the complete set of checks for data frames. + */ + gen_or(b1, b0); + + /* + * Now check for a data frame. + * I.e, check "link[0] & 0x08". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x08; + b1->stmts = s; + + /* + * AND that with the checks done for data frames. + */ + gen_and(b1, b0); + + /* + * If the high-order bit of the type value is 0, this + * is a management frame. + * I.e, check "!(link[0] & 0x08)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b2 = new_block(JMP(BPF_JSET)); + b2->s.k = 0x08; + b2->stmts = s; + gen_not(b2); + + /* + * For management frames, the DA is at 4. + */ + b1 = gen_mac_multicast(4); + gen_and(b2, b1); + + /* + * OR that with the checks done for data frames. + * That gives the checks done for management and + * data frames. + */ + gen_or(b1, b0); + + /* + * If the low-order bit of the type value is 1, + * this is either a control frame or a frame + * with a reserved type, and thus not a + * frame with an SA. + * + * I.e., check "!(link[0] & 0x04)". + */ + s = gen_load_a(OR_LINK, 0, BPF_B); + b1 = new_block(JMP(BPF_JSET)); + b1->s.k = 0x04; + b1->stmts = s; + gen_not(b1); + + /* + * AND that with the checks for data and management + * frames. + */ + gen_and(b1, b0); + return b0; + case DLT_IP_OVER_FC: + b0 = gen_mac_multicast(2); + return b0; + case DLT_SUNATM: + if (is_lane) { + /* + * Check that the packet doesn't begin with an + * LE Control marker. (We've already generated + * a test for LANE.) + */ + b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, + BPF_H, 0xFF00); + gen_not(b1); + + /* ether[off_mac] & 1 != 0 */ + b0 = gen_mac_multicast(off_mac); + gen_and(b1, b0); + return b0; + } + break; + default: + break; + } + /* Link not known to support multicasts */ + break; + + case Q_IP: + b0 = gen_linktype(ETHERTYPE_IP); + b1 = gen_cmp_ge(OR_NET, 16, BPF_B, (bpf_int32)224); + gen_and(b0, b1); + return b1; + + case Q_IPV6: + b0 = gen_linktype(ETHERTYPE_IPV6); + b1 = gen_cmp(OR_NET, 24, BPF_B, (bpf_int32)255); + gen_and(b0, b1); + return b1; + } + bpf_error("link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel"); + /* NOTREACHED */ + return NULL; +} + +/* + * Filter on inbound (dir == 0) or outbound (dir == 1) traffic. + * Outbound traffic is sent by this machine, while inbound traffic is + * sent by a remote machine (and may include packets destined for a + * unicast or multicast link-layer address we are not subscribing to). + * These are the same definitions implemented by pcap_setdirection(). + * Capturing only unicast traffic destined for this host is probably + * better accomplished using a higher-layer filter. + */ +struct block * +gen_inbound(dir) + int dir; +{ + register struct block *b0; + + /* + * Only some data link types support inbound/outbound qualifiers. + */ + switch (linktype) { + case DLT_SLIP: + b0 = gen_relation(BPF_JEQ, + gen_load(Q_LINK, gen_loadi(0), 1), + gen_loadi(0), + dir); + break; + + case DLT_IPNET: + if (dir) { + /* match outgoing packets */ + b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_OUTBOUND); + } else { + /* match incoming packets */ + b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_INBOUND); + } + break; + + case DLT_LINUX_SLL: + /* match outgoing packets */ + b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING); + if (!dir) { + /* to filter on inbound traffic, invert the match */ + gen_not(b0); + } + break; + +#ifdef HAVE_NET_PFVAR_H + case DLT_PFLOG: + b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, dir), BPF_B, + (bpf_int32)((dir == 0) ? PF_IN : PF_OUT)); + break; +#endif + + case DLT_PPP_PPPD: + if (dir) { + /* match outgoing packets */ + b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_OUT); + } else { + /* match incoming packets */ + b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_IN); + } + break; + + case DLT_JUNIPER_MFR: + case DLT_JUNIPER_MLFR: + case DLT_JUNIPER_MLPPP: + case DLT_JUNIPER_ATM1: + case DLT_JUNIPER_ATM2: + case DLT_JUNIPER_PPPOE: + case DLT_JUNIPER_PPPOE_ATM: + case DLT_JUNIPER_GGSN: + case DLT_JUNIPER_ES: + case DLT_JUNIPER_MONITOR: + case DLT_JUNIPER_SERVICES: + case DLT_JUNIPER_ETHER: + case DLT_JUNIPER_PPP: + case DLT_JUNIPER_FRELAY: + case DLT_JUNIPER_CHDLC: + case DLT_JUNIPER_VP: + case DLT_JUNIPER_ST: + case DLT_JUNIPER_ISM: + case DLT_JUNIPER_VS: + case DLT_JUNIPER_SRX_E2E: + case DLT_JUNIPER_FIBRECHANNEL: + case DLT_JUNIPER_ATM_CEMIC: + + /* juniper flags (including direction) are stored + * the byte after the 3-byte magic number */ + if (dir) { + /* match outgoing packets */ + b0 = gen_mcmp(OR_LINK, 3, BPF_B, 0, 0x01); + } else { + /* match incoming packets */ + b0 = gen_mcmp(OR_LINK, 3, BPF_B, 1, 0x01); + } + break; + + default: + /* + * If we have packet meta-data indicating a direction, + * check it, otherwise give up as this link-layer type + * has nothing in the packet data. + */ +#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER) + /* + * We infer that this is Linux with PF_PACKET support. + * If this is a *live* capture, we can look at + * special meta-data in the filter expression; + * if it's a savefile, we can't. + */ + if (bpf_pcap->sf.rfile != NULL) { + /* We have a FILE *, so this is a savefile */ + bpf_error("inbound/outbound not supported on linktype %d when reading savefiles", + linktype); + b0 = NULL; + /* NOTREACHED */ + } + /* match outgoing packets */ + b0 = gen_cmp(OR_LINK, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H, + PACKET_OUTGOING); + if (!dir) { + /* to filter on inbound traffic, invert the match */ + gen_not(b0); + } +#else /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */ + bpf_error("inbound/outbound not supported on linktype %d", + linktype); + b0 = NULL; + /* NOTREACHED */ +#endif /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */ + } + return (b0); +} + +#ifdef HAVE_NET_PFVAR_H +/* PF firewall log matched interface */ +struct block * +gen_pf_ifname(const char *ifname) +{ + struct block *b0; + u_int len, off; + + if (linktype != DLT_PFLOG) { + bpf_error("ifname supported only on PF linktype"); + /* NOTREACHED */ + } + len = sizeof(((struct pfloghdr *)0)->ifname); + off = offsetof(struct pfloghdr, ifname); + if (strlen(ifname) >= len) { + bpf_error("ifname interface names can only be %d characters", + len-1); + /* NOTREACHED */ + } + b0 = gen_bcmp(OR_LINK, off, strlen(ifname), (const u_char *)ifname); + return (b0); +} + +/* PF firewall log ruleset name */ +struct block * +gen_pf_ruleset(char *ruleset) +{ + struct block *b0; + + if (linktype != DLT_PFLOG) { + bpf_error("ruleset supported only on PF linktype"); + /* NOTREACHED */ + } + + if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) { + bpf_error("ruleset names can only be %ld characters", + (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1)); + /* NOTREACHED */ + } + + b0 = gen_bcmp(OR_LINK, offsetof(struct pfloghdr, ruleset), + strlen(ruleset), (const u_char *)ruleset); + return (b0); +} + +/* PF firewall log rule number */ +struct block * +gen_pf_rnr(int rnr) +{ + struct block *b0; + + if (linktype != DLT_PFLOG) { + bpf_error("rnr supported only on PF linktype"); + /* NOTREACHED */ + } + + b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, rulenr), BPF_W, + (bpf_int32)rnr); + return (b0); +} + +/* PF firewall log sub-rule number */ +struct block * +gen_pf_srnr(int srnr) +{ + struct block *b0; + + if (linktype != DLT_PFLOG) { + bpf_error("srnr supported only on PF linktype"); + /* NOTREACHED */ + } + + b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, subrulenr), BPF_W, + (bpf_int32)srnr); + return (b0); +} + +/* PF firewall log reason code */ +struct block * +gen_pf_reason(int reason) +{ + struct block *b0; + + if (linktype != DLT_PFLOG) { + bpf_error("reason supported only on PF linktype"); + /* NOTREACHED */ + } + + b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, reason), BPF_B, + (bpf_int32)reason); + return (b0); +} + +/* PF firewall log action */ +struct block * +gen_pf_action(int action) +{ + struct block *b0; + + if (linktype != DLT_PFLOG) { + bpf_error("action supported only on PF linktype"); + /* NOTREACHED */ + } + + b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, action), BPF_B, + (bpf_int32)action); + return (b0); +} +#else /* !HAVE_NET_PFVAR_H */ +struct block * +gen_pf_ifname(const char *ifname) +{ + bpf_error("libpcap was compiled without pf support"); + /* NOTREACHED */ + return (NULL); +} + +struct block * +gen_pf_ruleset(char *ruleset) +{ + bpf_error("libpcap was compiled on a machine without pf support"); + /* NOTREACHED */ + return (NULL); +} + +struct block * +gen_pf_rnr(int rnr) +{ + bpf_error("libpcap was compiled on a machine without pf support"); + /* NOTREACHED */ + return (NULL); +} + +struct block * +gen_pf_srnr(int srnr) +{ + bpf_error("libpcap was compiled on a machine without pf support"); + /* NOTREACHED */ + return (NULL); +} + +struct block * +gen_pf_reason(int reason) +{ + bpf_error("libpcap was compiled on a machine without pf support"); + /* NOTREACHED */ + return (NULL); +} + +struct block * +gen_pf_action(int action) +{ + bpf_error("libpcap was compiled on a machine without pf support"); + /* NOTREACHED */ + return (NULL); +} +#endif /* HAVE_NET_PFVAR_H */ + +/* IEEE 802.11 wireless header */ +struct block * +gen_p80211_type(int type, int mask) +{ + struct block *b0; + + switch (linktype) { + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + b0 = gen_mcmp(OR_LINK, 0, BPF_B, (bpf_int32)type, + (bpf_int32)mask); + break; + + default: + bpf_error("802.11 link-layer types supported only on 802.11"); + /* NOTREACHED */ + } + + return (b0); +} + +struct block * +gen_p80211_fcdir(int fcdir) +{ + struct block *b0; + + switch (linktype) { + + case DLT_IEEE802_11: + case DLT_PRISM_HEADER: + case DLT_IEEE802_11_RADIO_AVS: + case DLT_IEEE802_11_RADIO: + break; + + default: + bpf_error("frame direction supported only with 802.11 headers"); + /* NOTREACHED */ + } + + b0 = gen_mcmp(OR_LINK, 1, BPF_B, (bpf_int32)fcdir, + (bpf_u_int32)IEEE80211_FC1_DIR_MASK); + + return (b0); +} + +struct block * +gen_acode(eaddr, q) + register const u_char *eaddr; + struct qual q; +{ + switch (linktype) { + + case DLT_ARCNET: + case DLT_ARCNET_LINUX: + if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && + q.proto == Q_LINK) + return (gen_ahostop(eaddr, (int)q.dir)); + else { + bpf_error("ARCnet address used in non-arc expression"); + /* NOTREACHED */ + } + break; + + default: + bpf_error("aid supported only on ARCnet"); + /* NOTREACHED */ + } + bpf_error("ARCnet address used in non-arc expression"); + /* NOTREACHED */ + return NULL; +} + +static struct block * +gen_ahostop(eaddr, dir) + register const u_char *eaddr; + register int dir; +{ + register struct block *b0, *b1; + + switch (dir) { + /* src comes first, different from Ethernet */ + case Q_SRC: + return gen_bcmp(OR_LINK, 0, 1, eaddr); + + case Q_DST: + return gen_bcmp(OR_LINK, 1, 1, eaddr); + + case Q_AND: + b0 = gen_ahostop(eaddr, Q_SRC); + b1 = gen_ahostop(eaddr, Q_DST); + gen_and(b0, b1); + return b1; + + case Q_DEFAULT: + case Q_OR: + b0 = gen_ahostop(eaddr, Q_SRC); + b1 = gen_ahostop(eaddr, Q_DST); + gen_or(b0, b1); + return b1; + + case Q_ADDR1: + bpf_error("'addr1' is only supported on 802.11"); + break; + + case Q_ADDR2: + bpf_error("'addr2' is only supported on 802.11"); + break; + + case Q_ADDR3: + bpf_error("'addr3' is only supported on 802.11"); + break; + + case Q_ADDR4: + bpf_error("'addr4' is only supported on 802.11"); + break; + + case Q_RA: + bpf_error("'ra' is only supported on 802.11"); + break; + + case Q_TA: + bpf_error("'ta' is only supported on 802.11"); + break; + } + abort(); + /* NOTREACHED */ +} + +/* + * support IEEE 802.1Q VLAN trunk over ethernet + */ +struct block * +gen_vlan(vlan_num) + int vlan_num; +{ + struct block *b0, *b1; + + /* can't check for VLAN-encapsulated packets inside MPLS */ + if (label_stack_depth > 0) + bpf_error("no VLAN match after MPLS"); + + /* + * Check for a VLAN packet, and then change the offsets to point + * to the type and data fields within the VLAN packet. Just + * increment the offsets, so that we can support a hierarchy, e.g. + * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within + * VLAN 100. + * + * XXX - this is a bit of a kludge. If we were to split the + * compiler into a parser that parses an expression and + * generates an expression tree, and a code generator that + * takes an expression tree (which could come from our + * parser or from some other parser) and generates BPF code, + * we could perhaps make the offsets parameters of routines + * and, in the handler for an "AND" node, pass to subnodes + * other than the VLAN node the adjusted offsets. + * + * This would mean that "vlan" would, instead of changing the + * behavior of *all* tests after it, change only the behavior + * of tests ANDed with it. That would change the documented + * semantics of "vlan", which might break some expressions. + * However, it would mean that "(vlan and ip) or ip" would check + * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than + * checking only for VLAN-encapsulated IP, so that could still + * be considered worth doing; it wouldn't break expressions + * that are of the form "vlan and ..." or "vlan N and ...", + * which I suspect are the most common expressions involving + * "vlan". "vlan or ..." doesn't necessarily do what the user + * would really want, now, as all the "or ..." tests would + * be done assuming a VLAN, even though the "or" could be viewed + * as meaning "or, if this isn't a VLAN packet...". + */ + orig_nl = off_nl; + + switch (linktype) { + + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + /* check for VLAN, including QinQ */ + b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)ETHERTYPE_8021Q); + b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, + (bpf_int32)ETHERTYPE_8021QINQ); + gen_or(b0,b1); + b0 = b1; + + /* If a specific VLAN is requested, check VLAN id */ + if (vlan_num >= 0) { + b1 = gen_mcmp(OR_MACPL, 0, BPF_H, + (bpf_int32)vlan_num, 0x0fff); + gen_and(b0, b1); + b0 = b1; + } + + off_macpl += 4; + off_linktype += 4; +#if 0 + off_nl_nosnap += 4; + off_nl += 4; +#endif + break; + + default: + bpf_error("no VLAN support for data link type %d", + linktype); + /*NOTREACHED*/ + } + + return (b0); +} + +/* + * support for MPLS + */ +struct block * +gen_mpls(label_num) + int label_num; +{ + struct block *b0,*b1; + + /* + * Change the offsets to point to the type and data fields within + * the MPLS packet. Just increment the offsets, so that we + * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to + * capture packets with an outer label of 100000 and an inner + * label of 1024. + * + * XXX - this is a bit of a kludge. See comments in gen_vlan(). + */ + orig_nl = off_nl; + + if (label_stack_depth > 0) { + /* just match the bottom-of-stack bit clear */ + b0 = gen_mcmp(OR_MACPL, orig_nl-2, BPF_B, 0, 0x01); + } else { + /* + * Indicate that we're checking MPLS-encapsulated headers, + * to make sure higher level code generators don't try to + * match against IP-related protocols such as Q_ARP, Q_RARP + * etc. + */ + switch (linktype) { + + case DLT_C_HDLC: /* fall through */ + case DLT_EN10MB: + case DLT_NETANALYZER: + case DLT_NETANALYZER_TRANSPARENT: + b0 = gen_linktype(ETHERTYPE_MPLS); + break; + + case DLT_PPP: + b0 = gen_linktype(PPP_MPLS_UCAST); + break; + + /* FIXME add other DLT_s ... + * for Frame-Relay/and ATM this may get messy due to SNAP headers + * leave it for now */ + + default: + bpf_error("no MPLS support for data link type %d", + linktype); + b0 = NULL; + /*NOTREACHED*/ + break; + } + } + + /* If a specific MPLS label is requested, check it */ + if (label_num >= 0) { + label_num = label_num << 12; /* label is shifted 12 bits on the wire */ + b1 = gen_mcmp(OR_MACPL, orig_nl, BPF_W, (bpf_int32)label_num, + 0xfffff000); /* only compare the first 20 bits */ + gen_and(b0, b1); + b0 = b1; + } + + off_nl_nosnap += 4; + off_nl += 4; + label_stack_depth++; + return (b0); +} + +/* + * Support PPPOE discovery and session. + */ +struct block * +gen_pppoed() +{ + /* check for PPPoE discovery */ + return gen_linktype((bpf_int32)ETHERTYPE_PPPOED); +} + +struct block * +gen_pppoes() +{ + struct block *b0; + + /* + * Test against the PPPoE session link-layer type. + */ + b0 = gen_linktype((bpf_int32)ETHERTYPE_PPPOES); + + /* + * Change the offsets to point to the type and data fields within + * the PPP packet, and note that this is PPPoE rather than + * raw PPP. + * + * XXX - this is a bit of a kludge. If we were to split the + * compiler into a parser that parses an expression and + * generates an expression tree, and a code generator that + * takes an expression tree (which could come from our + * parser or from some other parser) and generates BPF code, + * we could perhaps make the offsets parameters of routines + * and, in the handler for an "AND" node, pass to subnodes + * other than the PPPoE node the adjusted offsets. + * + * This would mean that "pppoes" would, instead of changing the + * behavior of *all* tests after it, change only the behavior + * of tests ANDed with it. That would change the documented + * semantics of "pppoes", which might break some expressions. + * However, it would mean that "(pppoes and ip) or ip" would check + * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than + * checking only for VLAN-encapsulated IP, so that could still + * be considered worth doing; it wouldn't break expressions + * that are of the form "pppoes and ..." which I suspect are the + * most common expressions involving "pppoes". "pppoes or ..." + * doesn't necessarily do what the user would really want, now, + * as all the "or ..." tests would be done assuming PPPoE, even + * though the "or" could be viewed as meaning "or, if this isn't + * a PPPoE packet...". + */ + orig_linktype = off_linktype; /* save original values */ + orig_nl = off_nl; + is_pppoes = 1; + + /* + * The "network-layer" protocol is PPPoE, which has a 6-byte + * PPPoE header, followed by a PPP packet. + * + * There is no HDLC encapsulation for the PPP packet (it's + * encapsulated in PPPoES instead), so the link-layer type + * starts at the first byte of the PPP packet. For PPPoE, + * that offset is relative to the beginning of the total + * link-layer payload, including any 802.2 LLC header, so + * it's 6 bytes past off_nl. + */ + off_linktype = off_nl + 6; + + /* + * The network-layer offsets are relative to the beginning + * of the MAC-layer payload; that's past the 6-byte + * PPPoE header and the 2-byte PPP header. + */ + off_nl = 6+2; + off_nl_nosnap = 6+2; + + return b0; +} + +struct block * +gen_atmfield_code(atmfield, jvalue, jtype, reverse) + int atmfield; + bpf_int32 jvalue; + bpf_u_int32 jtype; + int reverse; +{ + struct block *b0; + + switch (atmfield) { + + case A_VPI: + if (!is_atm) + bpf_error("'vpi' supported only on raw ATM"); + if (off_vpi == (u_int)-1) + abort(); + b0 = gen_ncmp(OR_LINK, off_vpi, BPF_B, 0xffffffff, jtype, + reverse, jvalue); + break; + + case A_VCI: + if (!is_atm) + bpf_error("'vci' supported only on raw ATM"); + if (off_vci == (u_int)-1) + abort(); + b0 = gen_ncmp(OR_LINK, off_vci, BPF_H, 0xffffffff, jtype, + reverse, jvalue); + break; + + case A_PROTOTYPE: + if (off_proto == (u_int)-1) + abort(); /* XXX - this isn't on FreeBSD */ + b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0x0f, jtype, + reverse, jvalue); + break; + + case A_MSGTYPE: + if (off_payload == (u_int)-1) + abort(); + b0 = gen_ncmp(OR_LINK, off_payload + MSG_TYPE_POS, BPF_B, + 0xffffffff, jtype, reverse, jvalue); + break; + + case A_CALLREFTYPE: + if (!is_atm) + bpf_error("'callref' supported only on raw ATM"); + if (off_proto == (u_int)-1) + abort(); + b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0xffffffff, + jtype, reverse, jvalue); + break; + + default: + abort(); + } + return b0; +} + +struct block * +gen_atmtype_abbrev(type) + int type; +{ + struct block *b0, *b1; + + switch (type) { + + case A_METAC: + /* Get all packets in Meta signalling Circuit */ + if (!is_atm) + bpf_error("'metac' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 1, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_BCC: + /* Get all packets in Broadcast Circuit*/ + if (!is_atm) + bpf_error("'bcc' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 2, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_OAMF4SC: + /* Get all cells in Segment OAM F4 circuit*/ + if (!is_atm) + bpf_error("'oam4sc' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_OAMF4EC: + /* Get all cells in End-to-End OAM F4 Circuit*/ + if (!is_atm) + bpf_error("'oam4ec' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_SC: + /* Get all packets in connection Signalling Circuit */ + if (!is_atm) + bpf_error("'sc' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 5, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_ILMIC: + /* Get all packets in ILMI Circuit */ + if (!is_atm) + bpf_error("'ilmic' supported only on raw ATM"); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 16, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_LANE: + /* Get all LANE packets */ + if (!is_atm) + bpf_error("'lane' supported only on raw ATM"); + b1 = gen_atmfield_code(A_PROTOTYPE, PT_LANE, BPF_JEQ, 0); + + /* + * Arrange that all subsequent tests assume LANE + * rather than LLC-encapsulated packets, and set + * the offsets appropriately for LANE-encapsulated + * Ethernet. + * + * "off_mac" is the offset of the Ethernet header, + * which is 2 bytes past the ATM pseudo-header + * (skipping the pseudo-header and 2-byte LE Client + * field). The other offsets are Ethernet offsets + * relative to "off_mac". + */ + is_lane = 1; + off_mac = off_payload + 2; /* MAC header */ + off_linktype = off_mac + 12; + off_macpl = off_mac + 14; /* Ethernet */ + off_nl = 0; /* Ethernet II */ + off_nl_nosnap = 3; /* 802.3+802.2 */ + break; + + case A_LLC: + /* Get all LLC-encapsulated packets */ + if (!is_atm) + bpf_error("'llc' supported only on raw ATM"); + b1 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); + is_lane = 0; + break; + + default: + abort(); + } + return b1; +} + +/* + * Filtering for MTP2 messages based on li value + * FISU, length is null + * LSSU, length is 1 or 2 + * MSU, length is 3 or more + */ +struct block * +gen_mtp2type_abbrev(type) + int type; +{ + struct block *b0, *b1; + + switch (type) { + + case M_FISU: + if ( (linktype != DLT_MTP2) && + (linktype != DLT_ERF) && + (linktype != DLT_MTP2_WITH_PHDR) ) + bpf_error("'fisu' supported only on MTP2"); + /* gen_ncmp(offrel, offset, size, mask, jtype, reverse, value) */ + b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0); + break; + + case M_LSSU: + if ( (linktype != DLT_MTP2) && + (linktype != DLT_ERF) && + (linktype != DLT_MTP2_WITH_PHDR) ) + bpf_error("'lssu' supported only on MTP2"); + b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 1, 2); + b1 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 0); + gen_and(b1, b0); + break; + + case M_MSU: + if ( (linktype != DLT_MTP2) && + (linktype != DLT_ERF) && + (linktype != DLT_MTP2_WITH_PHDR) ) + bpf_error("'msu' supported only on MTP2"); + b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 2); + break; + + default: + abort(); + } + return b0; +} + +struct block * +gen_mtp3field_code(mtp3field, jvalue, jtype, reverse) + int mtp3field; + bpf_u_int32 jvalue; + bpf_u_int32 jtype; + int reverse; +{ + struct block *b0; + bpf_u_int32 val1 , val2 , val3; + + switch (mtp3field) { + + case M_SIO: + if (off_sio == (u_int)-1) + bpf_error("'sio' supported only on SS7"); + /* sio coded on 1 byte so max value 255 */ + if(jvalue > 255) + bpf_error("sio value %u too big; max value = 255", + jvalue); + b0 = gen_ncmp(OR_PACKET, off_sio, BPF_B, 0xffffffff, + (u_int)jtype, reverse, (u_int)jvalue); + break; + + case M_OPC: + if (off_opc == (u_int)-1) + bpf_error("'opc' supported only on SS7"); + /* opc coded on 14 bits so max value 16383 */ + if (jvalue > 16383) + bpf_error("opc value %u too big; max value = 16383", + jvalue); + /* the following instructions are made to convert jvalue + * to the form used to write opc in an ss7 message*/ + val1 = jvalue & 0x00003c00; + val1 = val1 >>10; + val2 = jvalue & 0x000003fc; + val2 = val2 <<6; + val3 = jvalue & 0x00000003; + val3 = val3 <<22; + jvalue = val1 + val2 + val3; + b0 = gen_ncmp(OR_PACKET, off_opc, BPF_W, 0x00c0ff0f, + (u_int)jtype, reverse, (u_int)jvalue); + break; + + case M_DPC: + if (off_dpc == (u_int)-1) + bpf_error("'dpc' supported only on SS7"); + /* dpc coded on 14 bits so max value 16383 */ + if (jvalue > 16383) + bpf_error("dpc value %u too big; max value = 16383", + jvalue); + /* the following instructions are made to convert jvalue + * to the forme used to write dpc in an ss7 message*/ + val1 = jvalue & 0x000000ff; + val1 = val1 << 24; + val2 = jvalue & 0x00003f00; + val2 = val2 << 8; + jvalue = val1 + val2; + b0 = gen_ncmp(OR_PACKET, off_dpc, BPF_W, 0xff3f0000, + (u_int)jtype, reverse, (u_int)jvalue); + break; + + case M_SLS: + if (off_sls == (u_int)-1) + bpf_error("'sls' supported only on SS7"); + /* sls coded on 4 bits so max value 15 */ + if (jvalue > 15) + bpf_error("sls value %u too big; max value = 15", + jvalue); + /* the following instruction is made to convert jvalue + * to the forme used to write sls in an ss7 message*/ + jvalue = jvalue << 4; + b0 = gen_ncmp(OR_PACKET, off_sls, BPF_B, 0xf0, + (u_int)jtype,reverse, (u_int)jvalue); + break; + + default: + abort(); + } + return b0; +} + +static struct block * +gen_msg_abbrev(type) + int type; +{ + struct block *b1; + + /* + * Q.2931 signalling protocol messages for handling virtual circuits + * establishment and teardown + */ + switch (type) { + + case A_SETUP: + b1 = gen_atmfield_code(A_MSGTYPE, SETUP, BPF_JEQ, 0); + break; + + case A_CALLPROCEED: + b1 = gen_atmfield_code(A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0); + break; + + case A_CONNECT: + b1 = gen_atmfield_code(A_MSGTYPE, CONNECT, BPF_JEQ, 0); + break; + + case A_CONNECTACK: + b1 = gen_atmfield_code(A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0); + break; + + case A_RELEASE: + b1 = gen_atmfield_code(A_MSGTYPE, RELEASE, BPF_JEQ, 0); + break; + + case A_RELEASE_DONE: + b1 = gen_atmfield_code(A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0); + break; + + default: + abort(); + } + return b1; +} + +struct block * +gen_atmmulti_abbrev(type) + int type; +{ + struct block *b0, *b1; + + switch (type) { + + case A_OAM: + if (!is_atm) + bpf_error("'oam' supported only on raw ATM"); + b1 = gen_atmmulti_abbrev(A_OAMF4); + break; + + case A_OAMF4: + if (!is_atm) + bpf_error("'oamf4' supported only on raw ATM"); + /* OAM F4 type */ + b0 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0); + b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0); + gen_or(b0, b1); + b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); + gen_and(b0, b1); + break; + + case A_CONNECTMSG: + /* + * Get Q.2931 signalling messages for switched + * virtual connection + */ + if (!is_atm) + bpf_error("'connectmsg' supported only on raw ATM"); + b0 = gen_msg_abbrev(A_SETUP); + b1 = gen_msg_abbrev(A_CALLPROCEED); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_CONNECT); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_CONNECTACK); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_RELEASE); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_RELEASE_DONE); + gen_or(b0, b1); + b0 = gen_atmtype_abbrev(A_SC); + gen_and(b0, b1); + break; + + case A_METACONNECT: + if (!is_atm) + bpf_error("'metaconnect' supported only on raw ATM"); + b0 = gen_msg_abbrev(A_SETUP); + b1 = gen_msg_abbrev(A_CALLPROCEED); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_CONNECT); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_RELEASE); + gen_or(b0, b1); + b0 = gen_msg_abbrev(A_RELEASE_DONE); + gen_or(b0, b1); + b0 = gen_atmtype_abbrev(A_METAC); + gen_and(b0, b1); + break; + + default: + abort(); + } + return b1; +} |