diff options
Diffstat (limited to 'cpukit/libnetworking/netinet/ip_input.c')
| -rw-r--r-- | cpukit/libnetworking/netinet/ip_input.c | 1506 |
1 files changed, 1506 insertions, 0 deletions
diff --git a/cpukit/libnetworking/netinet/ip_input.c b/cpukit/libnetworking/netinet/ip_input.c new file mode 100644 index 0000000000..582067d1a6 --- /dev/null +++ b/cpukit/libnetworking/netinet/ip_input.c @@ -0,0 +1,1506 @@ +/* + * Copyright (c) 1982, 1986, 1988, 1993 + * 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 the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 + * $Id$ + * $ANA: ip_input.c,v 1.5 1996/09/18 14:34:59 wollman Exp $ + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#define _IP_VHL + +#include "opt_ipfw.h" + +#include <stddef.h> + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/mbuf.h> +#include <sys/malloc.h> +#include <sys/domain.h> +#include <sys/protosw.h> +#include <sys/socket.h> +#include <errno.h> +#include <sys/time.h> +#include <sys/kernel.h> +#include <sys/syslog.h> +#include <sys/sysctl.h> + +#include <net/if.h> +#include <net/if_dl.h> +#include <net/route.h> +#include <net/netisr.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/in_var.h> +#include <netinet/ip.h> +#include <netinet/in_pcb.h> +#include <netinet/ip_var.h> +#include <netinet/ip_icmp.h> +#include <machine/in_cksum.h> + +#include <sys/socketvar.h> + +#ifdef IPFIREWALL +#include <netinet/ip_fw.h> +#endif + +int rsvp_on = 0; +static int ip_rsvp_on; +struct socket *ip_rsvpd; + +int ipforwarding = 0; +SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, + &ipforwarding, 0, "Enable IP forwarding between interfaces"); + +static int ipsendredirects = 1; /* XXX */ +SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, + &ipsendredirects, 0, "Enable sending IP redirects"); + +int ip_defttl = IPDEFTTL; +SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, + &ip_defttl, 0, "Maximum TTL on IP packets"); + +static int ip_dosourceroute = 0; +SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, + &ip_dosourceroute, 0, ""); + +static int ip_acceptsourceroute = 0; +SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, + CTLFLAG_RW, &ip_acceptsourceroute, 0, ""); +#ifdef DIAGNOSTIC +static int ipprintfs = 0; +#endif + +extern struct domain inetdomain; +extern struct protosw inetsw[]; +u_char ip_protox[IPPROTO_MAX]; +static int ipqmaxlen = IFQ_MAXLEN; +struct in_ifaddr *in_ifaddr; /* first inet address */ +struct ifqueue ipintrq; +SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, + &ipintrq.ifq_maxlen, 0, ""); +SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, + &ipintrq.ifq_drops, 0, + "Number of packets dropped from the IP input queue"); + +struct ipstat ipstat; + +/* Packet reassembly stuff */ +#define IPREASS_NHASH_LOG2 6 +#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) +#define IPREASS_HMASK (IPREASS_NHASH - 1) +#define IPREASS_HASH(x,y) \ + (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) + +static struct ipq ipq[IPREASS_NHASH]; +static int nipq = 0; /* total # of reass queues */ +static int maxnipq; + +#ifdef IPCTL_DEFMTU +SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, + &ip_mtu, 0, "Default MTU"); +#endif + +#if !defined(COMPAT_IPFW) || COMPAT_IPFW == 1 +#undef COMPAT_IPFW +#define COMPAT_IPFW 1 +#else +#undef COMPAT_IPFW +#endif + +#ifdef COMPAT_IPFW +/* Firewall hooks */ +ip_fw_chk_t *ip_fw_chk_ptr; +ip_fw_ctl_t *ip_fw_ctl_ptr; + +/* IP Network Address Translation (NAT) hooks */ +ip_nat_t *ip_nat_ptr; +ip_nat_ctl_t *ip_nat_ctl_ptr; +#endif + +/* + * We need to save the IP options in case a protocol wants to respond + * to an incoming packet over the same route if the packet got here + * using IP source routing. This allows connection establishment and + * maintenance when the remote end is on a network that is not known + * to us. + */ +static int ip_nhops = 0; +static struct ip_srcrt { + struct in_addr dst; /* final destination */ + char nop; /* one NOP to align */ + char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ + struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; +} ip_srcrt; + +#ifdef IPDIVERT +/* + * Shared variable between ip_input() and ip_reass() to communicate + * about which packets, once assembled from fragments, get diverted, + * and to which port. + */ +static u_short frag_divert_port; +#endif + +static void save_rte(u_char *, struct in_addr); +static void ip_deq(struct ipasfrag *); +static int ip_dooptions(struct mbuf *); +static void ip_enq(struct ipasfrag *, struct ipasfrag *); +static void ip_forward(struct mbuf *, int); +static void ip_freef(struct ipq *); +static struct ip * + ip_reass(struct ipasfrag *, struct ipq *, struct ipq *); +static struct in_ifaddr * + ip_rtaddr(struct in_addr); +void ipintr(void); +/* + * IP initialization: fill in IP protocol switch table. + * All protocols not implemented in kernel go to raw IP protocol handler. + */ +void +ip_init(void) +{ + register struct protosw *pr; + register int i; + + pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); + if (pr == NULL) + panic("ip_init: PF_INET not found"); + + /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ + for (i = 0; i < IPPROTO_MAX; i++) + ip_protox[i] = pr - inetsw; + /* + * Cycle through IP protocols and put them into the appropriate place + * in ip_protox[]. + */ + for (pr = inetdomain.dom_protosw; + pr < inetdomain.dom_protoswNPROTOSW; pr++) + if (pr->pr_domain->dom_family == PF_INET && + pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { + ip_protox[pr->pr_protocol] = pr - inetsw; + } + + for (i = 0; i < IPREASS_NHASH; i++) + ipq[i].next = ipq[i].prev = &ipq[i]; + + maxnipq = nmbclusters/4; + + /* Initialize various other remaining things. */ + ip_id = rtems_bsdnet_seconds_since_boot() & 0xffff; + ipintrq.ifq_maxlen = ipqmaxlen; +#ifdef IPFIREWALL + ip_fw_init(); +#endif +#ifdef IPNAT + ip_nat_init(); +#endif + +} + +static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET, 0, {0}, {0} }; +static struct route ipforward_rt; + +/* + * Ip input routine. Checksum and byte swap header. If fragmented + * try to reassemble. Process options. Pass to next level. + */ +void +ip_input(struct mbuf *m) +{ + struct ip *ip = NULL; + struct ipq *fp; + struct in_ifaddr *ia = NULL; + int i, hlen; + u_short sum; + +#ifdef DIAGNOSTIC + if ((m->m_flags & M_PKTHDR) == 0) + panic("ip_input no HDR"); +#endif + /* + * If no IP addresses have been set yet but the interfaces + * are receiving, can't do anything with incoming packets yet. + */ + if (in_ifaddr == NULL) + goto bad; + ipstat.ips_total++; + + if (m->m_pkthdr.len < sizeof(struct ip)) + goto tooshort; + +#if defined(DIAGNOSTIC) && defined(ORIGINAL_FREEBSD_CODE) + if (m->m_len < sizeof(struct ip)) + panic("ipintr mbuf too short"); +#endif + + if (m->m_len < sizeof (struct ip) && + (m = m_pullup(m, sizeof (struct ip))) == NULL) { + ipstat.ips_toosmall++; + return; + } + ip = mtod(m, struct ip *); + +#ifdef _IP_VHL + if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { +#else + if (ip->ip_v != IPVERSION) { +#endif + ipstat.ips_badvers++; + goto bad; + } + +#ifdef _IP_VHL + hlen = IP_VHL_HL(ip->ip_vhl) << 2; +#else + hlen = ip->ip_hl << 2; +#endif + if (hlen < sizeof(struct ip)) { /* minimum header length */ + ipstat.ips_badhlen++; + goto bad; + } + if (hlen > m->m_len) { + if ((m = m_pullup(m, hlen)) == NULL) { + ipstat.ips_badhlen++; + return; + } + ip = mtod(m, struct ip *); + } + if (hlen == sizeof(struct ip)) { + sum = in_cksum_hdr(ip); + } else { + sum = in_cksum(m, hlen); + } + if (sum) { + ipstat.ips_badsum++; + goto bad; + } + + /* + * Convert fields to host representation. + */ + ip->ip_len = ntohs(ip->ip_len); + if (ip->ip_len < hlen) { + ipstat.ips_badlen++; + goto bad; + } + NTOHS(ip->ip_id); + ip->ip_off = ntohs(ip->ip_off); + + /* + * Check that the amount of data in the buffers + * is as at least much as the IP header would have us expect. + * Trim mbufs if longer than we expect. + * Drop packet if shorter than we expect. + */ + if (m->m_pkthdr.len < ip->ip_len) { +tooshort: + ipstat.ips_tooshort++; + goto bad; + } + if (m->m_pkthdr.len > ip->ip_len) { + if (m->m_len == m->m_pkthdr.len) { + m->m_len = ip->ip_len; + m->m_pkthdr.len = ip->ip_len; + } else + m_adj(m, ip->ip_len - m->m_pkthdr.len); + } + /* + * IpHack's section. + * Right now when no processing on packet has done + * and it is still fresh out of network we do our black + * deals with it. + * - Firewall: deny/allow/divert + * - Xlate: translate packet's addr/port (NAT). + * - Wrap: fake packet's addr/port <unimpl.> + * - Encapsulate: put it in another IP and send out. <unimp.> + */ + +#ifdef COMPAT_IPFW + if (ip_fw_chk_ptr) { +#ifdef IPDIVERT + u_short port; + + port = (*ip_fw_chk_ptr)(&ip, hlen, NULL, ip_divert_ignore, &m); + ip_divert_ignore = 0; + if (port) { /* Divert packet */ + frag_divert_port = port; + goto ours; + } +#else + /* If ipfw says divert, we have to just drop packet */ + if ((*ip_fw_chk_ptr)(&ip, hlen, NULL, 0, &m)) { + m_freem(m); + m = NULL; + } +#endif + if (!m) + return; + } + + if (ip_nat_ptr && !(*ip_nat_ptr)(&ip, &m, m->m_pkthdr.rcvif, IP_NAT_IN)) + return; +#endif + + /* + * Process options and, if not destined for us, + * ship it on. ip_dooptions returns 1 when an + * error was detected (causing an icmp message + * to be sent and the original packet to be freed). + */ + ip_nhops = 0; /* for source routed packets */ + if (hlen > sizeof (struct ip) && ip_dooptions(m)) + return; + + /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no + * matter if it is destined to another node, or whether it is + * a multicast one, RSVP wants it! and prevents it from being forwarded + * anywhere else. Also checks if the rsvp daemon is running before + * grabbing the packet. + */ + if (rsvp_on && ip->ip_p==IPPROTO_RSVP) + goto ours; + + /* + * Check our list of addresses, to see if the packet is for us. + */ + for (ia = in_ifaddr; ia; ia = ia->ia_next) { +#define satosin(sa) ((struct sockaddr_in *)(sa)) + + if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) + goto ours; +#ifdef BOOTP_COMPAT + if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) + goto ours; +#endif + if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { + if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == + ip->ip_dst.s_addr) + goto ours; + if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) + goto ours; + } + } + if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { + struct in_multi *inm; + if (ip_mrouter) { + /* + * If we are acting as a multicast router, all + * incoming multicast packets are passed to the + * kernel-level multicast forwarding function. + * The packet is returned (relatively) intact; if + * ip_mforward() returns a non-zero value, the packet + * must be discarded, else it may be accepted below. + * + * (The IP ident field is put in the same byte order + * as expected when ip_mforward() is called from + * ip_output().) + */ + ip->ip_id = htons(ip->ip_id); + if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { + ipstat.ips_cantforward++; + m_freem(m); + return; + } + ip->ip_id = ntohs(ip->ip_id); + + /* + * The process-level routing daemon needs to receive + * all multicast IGMP packets, whether or not this + * host belongs to their destination groups. + */ + if (ip->ip_p == IPPROTO_IGMP) + goto ours; + ipstat.ips_forward++; + } + /* + * See if we belong to the destination multicast group on the + * arrival interface. + */ + IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); + if (inm == NULL) { + ipstat.ips_cantforward++; + m_freem(m); + return; + } + goto ours; + } + if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) + goto ours; + if (ip->ip_dst.s_addr == INADDR_ANY) + goto ours; + + /* + * Not for us; forward if possible and desirable. + */ + if (ipforwarding == 0) { + ipstat.ips_cantforward++; + m_freem(m); + } else { + ip_forward(m, 0); + } + return; + +ours: + + /* + * If offset or IP_MF are set, must reassemble. + * Otherwise, nothing need be done. + * (We could look in the reassembly queue to see + * if the packet was previously fragmented, + * but it's not worth the time; just let them time out.) + */ + if (ip->ip_off &~ (IP_DF | IP_RF)) { + if (m->m_flags & M_EXT) { /* XXX */ + if ((m = m_pullup(m, sizeof (struct ip))) == 0) { + ipstat.ips_toosmall++; +#ifdef IPDIVERT + frag_divert_port = 0; +#endif + return; + } + ip = mtod(m, struct ip *); + } + sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); + /* + * Look for queue of fragments + * of this datagram. + */ + for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) + if (ip->ip_id == fp->ipq_id && + ip->ip_src.s_addr == fp->ipq_src.s_addr && + ip->ip_dst.s_addr == fp->ipq_dst.s_addr && + ip->ip_p == fp->ipq_p) + goto found; + + fp = 0; + + /* check if there's a place for the new queue */ + if (nipq > maxnipq) { + /* + * drop something from the tail of the current queue + * before proceeding further + */ + if (ipq[sum].prev == &ipq[sum]) { /* gak */ + for (i = 0; i < IPREASS_NHASH; i++) { + if (ipq[i].prev != &ipq[i]) { + ip_freef(ipq[i].prev); + break; + } + } + } else + ip_freef(ipq[sum].prev); + } +found: + /* + * Adjust ip_len to not reflect header, + * set ip_mff if more fragments are expected, + * convert offset of this to bytes. + */ + ip->ip_len -= hlen; + ((struct ipasfrag *)ip)->ipf_mff &= ~1; + if (ip->ip_off & IP_MF) + ((struct ipasfrag *)ip)->ipf_mff |= 1; + ip->ip_off <<= 3; + + /* + * If datagram marked as having more fragments + * or if this is not the first fragment, + * attempt reassembly; if it succeeds, proceed. + */ + if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) { + ipstat.ips_fragments++; + ip = ip_reass((struct ipasfrag *)ip, fp, &ipq[sum]); + if (ip == 0) + return; + ipstat.ips_reassembled++; + m = dtom(ip); +#ifdef IPDIVERT + if (frag_divert_port) { + ip->ip_len += hlen; + HTONS(ip->ip_len); + HTONS(ip->ip_off); + HTONS(ip->ip_id); + ip->ip_sum = 0; + ip->ip_sum = in_cksum_hdr(ip); + NTOHS(ip->ip_id); + NTOHS(ip->ip_off); + NTOHS(ip->ip_len); + ip->ip_len -= hlen; + } +#endif + } else + if (fp) + ip_freef(fp); + } else + ip->ip_len -= hlen; + +#ifdef IPDIVERT + /* + * Divert reassembled packets to the divert protocol if required + */ + if (frag_divert_port) { + ipstat.ips_delivered++; + ip_divert_port = frag_divert_port; + frag_divert_port = 0; + (*inetsw[ip_protox[IPPROTO_DIVERT]].pr_input)(m, hlen); + return; + } + + /* Don't let packets divert themselves */ + if (ip->ip_p == IPPROTO_DIVERT) { + ipstat.ips_noproto++; + goto bad; + } +#endif + + /* + * Switch out to protocol's input routine. + */ + ipstat.ips_delivered++; + + (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); + return; +bad: + m_freem(m); +} + +/* + * IP software interrupt routine - to go away sometime soon + */ +void +ipintr(void) +{ + int s; + struct mbuf *m; + + while(1) { + s = splimp(); + IF_DEQUEUE(&ipintrq, m); + splx(s); + if (m == 0) + return; + ip_input(m); + } +} + +NETISR_SET(NETISR_IP, ipintr); + +/* + * Take incoming datagram fragment and try to + * reassemble it into whole datagram. If a chain for + * reassembly of this datagram already exists, then it + * is given as fp; otherwise have to make a chain. + */ +static struct ip * +ip_reass(struct ipasfrag *ip, struct ipq *fp, struct ipq *where) +{ + register struct mbuf *m = dtom(ip); + register struct ipasfrag *q; + struct mbuf *t; + int hlen = ip->ip_hl << 2; + int i; + int32_t next; + + /* + * Presence of header sizes in mbufs + * would confuse code below. + */ + m->m_data += hlen; + m->m_len -= hlen; + + /* + * If first fragment to arrive, create a reassembly queue. + */ + if (fp == NULL) { + if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) + goto dropfrag; + fp = mtod(t, struct ipq *); + insque(fp, where); + nipq++; + fp->ipq_ttl = IPFRAGTTL; + fp->ipq_p = ip->ip_p; + fp->ipq_id = ip->ip_id; + fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp; + fp->ipq_src = ((struct ip *)ip)->ip_src; + fp->ipq_dst = ((struct ip *)ip)->ip_dst; +#ifdef IPDIVERT + fp->ipq_divert = 0; +#endif + q = (struct ipasfrag *)fp; + goto insert; + } + + /* + * Find a segment which begins after this one does. + */ + for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) + if (q->ip_off > ip->ip_off) + break; + + /* + * If there is a preceding segment, it may provide some of + * our data already. If so, drop the data from the incoming + * segment. If it provides all of our data, drop us. + */ + if (q->ipf_prev != (struct ipasfrag *)fp) { + i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off; + if (i > 0) { + if (i >= ip->ip_len) + goto dropfrag; + m_adj(dtom(ip), i); + ip->ip_off += i; + ip->ip_len -= i; + } + } + + /* + * While we overlap succeeding segments trim them or, + * if they are completely covered, dequeue them. + */ + while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) { + struct mbuf *m0; + + i = (ip->ip_off + ip->ip_len) - q->ip_off; + if (i < q->ip_len) { + q->ip_len -= i; + q->ip_off += i; + m_adj(dtom(q), i); + break; + } + m0 = dtom(q); + q = q->ipf_next; + ip_deq(q->ipf_prev); + m_freem(m0); + } + +insert: + +#ifdef IPDIVERT + /* + * Any fragment diverting causes the whole packet to divert + */ + if (frag_divert_port != 0) + fp->ipq_divert = frag_divert_port; + frag_divert_port = 0; +#endif + + /* + * Stick new segment in its place; + * check for complete reassembly. + */ + ip_enq(ip, q->ipf_prev); + next = 0; + for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) { + if (q->ip_off != next) + return (0); + next += q->ip_len; + } + if (q->ipf_prev->ipf_mff & 1) + return (0); + + /* + * Reassembly is complete. Make sure the packet is a sane size. + */ +#ifdef _IP_VHL + if (next + (IP_VHL_HL(((struct ip *)fp->ipq_next)->ip_vhl) << 2) +#else + if (next + ((((struct ip *)fp->ipq_next)->ip_hl) << 2) +#endif + > IP_MAXPACKET) { + ipstat.ips_toolong++; + ip_freef(fp); + return (0); + } + + /* + * Concatenate fragments. + */ + q = fp->ipq_next; + m = dtom(q); + t = m->m_next; + m->m_next = NULL; + m_cat(m, t); + q = q->ipf_next; + while (q != (struct ipasfrag *)fp) { + t = dtom(q); + q = q->ipf_next; + m_cat(m, t); + } + +#ifdef IPDIVERT + /* + * Record divert port for packet, if any + */ + frag_divert_port = fp->ipq_divert; +#endif + + /* + * Create header for new ip packet by modifying header of first + * packet; dequeue and discard fragment reassembly header. + * Make header visible. + */ + ip = fp->ipq_next; + ip->ip_len = next; + ip->ipf_mff &= ~1; + ((struct ip *)ip)->ip_src = fp->ipq_src; + ((struct ip *)ip)->ip_dst = fp->ipq_dst; + remque(fp); + nipq--; + (void) m_free(dtom(fp)); + m = dtom(ip); + m->m_len += (ip->ip_hl << 2); + m->m_data -= (ip->ip_hl << 2); + /* some debugging cruft by sklower, below, will go away soon */ + if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ + register int plen = 0; + for (t = m; m; m = m->m_next) + plen += m->m_len; + t->m_pkthdr.len = plen; + } + return ((struct ip *)ip); + +dropfrag: + ipstat.ips_fragdropped++; + m_freem(m); + return (0); +} + +/* + * Free a fragment reassembly header and all + * associated datagrams. + */ +static void +ip_freef(struct ipq *fp) +{ + register struct ipasfrag *q, *p; + + for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) { + p = q->ipf_next; + ip_deq(q); + m_freem(dtom(q)); + } + remque(fp); + (void) m_free(dtom(fp)); + nipq--; +} + +/* + * Put an ip fragment on a reassembly chain. + * Like insque, but pointers in middle of structure. + */ +static void +ip_enq(struct ipasfrag *p, struct ipasfrag *prev) +{ + + p->ipf_prev = prev; + p->ipf_next = prev->ipf_next; + prev->ipf_next->ipf_prev = p; + prev->ipf_next = p; +} + +/* + * To ip_enq as remque is to insque. + */ +static void +ip_deq(struct ipasfrag *p) +{ + + p->ipf_prev->ipf_next = p->ipf_next; + p->ipf_next->ipf_prev = p->ipf_prev; +} + +/* + * IP timer processing; + * if a timer expires on a reassembly + * queue, discard it. + */ +void +ip_slowtimo(void) +{ + register struct ipq *fp; + int s = splnet(); + int i; + + for (i = 0; i < IPREASS_NHASH; i++) { + fp = ipq[i].next; + if (fp == 0) + continue; + while (fp != &ipq[i]) { + --fp->ipq_ttl; + fp = fp->next; + if (fp->prev->ipq_ttl == 0) { + ipstat.ips_fragtimeout++; + ip_freef(fp->prev); + } + } + } + splx(s); +} + +/* + * Drain off all datagram fragments. + */ +void +ip_drain(void) +{ + int i; + + for (i = 0; i < IPREASS_NHASH; i++) { + while (ipq[i].next != &ipq[i]) { + ipstat.ips_fragdropped++; + ip_freef(ipq[i].next); + } + } + in_rtqdrain(); +} + +/* + * Do option processing on a datagram, + * possibly discarding it if bad options are encountered, + * or forwarding it if source-routed. + * Returns 1 if packet has been forwarded/freed, + * 0 if the packet should be processed further. + */ +static int +ip_dooptions(struct mbuf *m) +{ + register struct ip *ip = mtod(m, struct ip *); + register u_char *cp; + register struct ip_timestamp *ipt; + register struct in_ifaddr *ia; + int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; + struct in_addr *sin, dst; + n_time ntime; + + dst = ip->ip_dst; + cp = (u_char *)(ip + 1); +#ifdef _IP_VHL + cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); +#else + cnt = (ip->ip_hl << 2) - sizeof (struct ip); +#endif + for (; cnt > 0; cnt -= optlen, cp += optlen) { + opt = cp[IPOPT_OPTVAL]; + if (opt == IPOPT_EOL) + break; + if (opt == IPOPT_NOP) + optlen = 1; + else { + optlen = cp[IPOPT_OLEN]; + if (optlen <= 0 || optlen > cnt) { + code = &cp[IPOPT_OLEN] - (u_char *)ip; + goto bad; + } + } + switch (opt) { + + default: + break; + + /* + * Source routing with record. + * Find interface with current destination address. + * If none on this machine then drop if strictly routed, + * or do nothing if loosely routed. + * Record interface address and bring up next address + * component. If strictly routed make sure next + * address is on directly accessible net. + */ + case IPOPT_LSRR: + case IPOPT_SSRR: + if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { + code = &cp[IPOPT_OFFSET] - (u_char *)ip; + goto bad; + } + ipaddr.sin_addr = ip->ip_dst; + ia = (struct in_ifaddr *) + ifa_ifwithaddr((struct sockaddr *)&ipaddr); + if (ia == 0) { + if (opt == IPOPT_SSRR) { + type = ICMP_UNREACH; + code = ICMP_UNREACH_SRCFAIL; + goto bad; + } + if (!ip_dosourceroute) + goto nosourcerouting; + /* + * Loose routing, and not at next destination + * yet; nothing to do except forward. + */ + break; + } + off--; /* 0 origin */ + if (off > optlen - sizeof(struct in_addr)) { + /* + * End of source route. Should be for us. + */ + if (!ip_acceptsourceroute) + goto nosourcerouting; + save_rte(cp, ip->ip_src); + break; + } + + if (!ip_dosourceroute) { + char buf[4*sizeof "123"]; + +nosourcerouting: + strcpy(buf, inet_ntoa(ip->ip_dst)); + log(LOG_WARNING, + "attempted source route from %s to %s\n", + inet_ntoa(ip->ip_src), buf); + type = ICMP_UNREACH; + code = ICMP_UNREACH_SRCFAIL; + goto bad; + } + + /* + * locate outgoing interface + */ + (void)memcpy(&ipaddr.sin_addr, cp + off, + sizeof(ipaddr.sin_addr)); + + if (opt == IPOPT_SSRR) { +#define INA struct in_ifaddr * +#define SA struct sockaddr * + if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) + ia = (INA)ifa_ifwithnet((SA)&ipaddr); + } else + ia = ip_rtaddr(ipaddr.sin_addr); + if (ia == 0) { + type = ICMP_UNREACH; + code = ICMP_UNREACH_SRCFAIL; + goto bad; + } + ip->ip_dst = ipaddr.sin_addr; + (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), + sizeof(struct in_addr)); + cp[IPOPT_OFFSET] += sizeof(struct in_addr); + /* + * Let ip_intr's mcast routing check handle mcast pkts + */ + forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); + break; + + case IPOPT_RR: + if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { + code = &cp[IPOPT_OFFSET] - (u_char *)ip; + goto bad; + } + /* + * If no space remains, ignore. + */ + off--; /* 0 origin */ + if (off > optlen - sizeof(struct in_addr)) + break; + (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, + sizeof(ipaddr.sin_addr)); + /* + * locate outgoing interface; if we're the destination, + * use the incoming interface (should be same). + */ + if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && + (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { + type = ICMP_UNREACH; + code = ICMP_UNREACH_HOST; + goto bad; + } + (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), + sizeof(struct in_addr)); + cp[IPOPT_OFFSET] += sizeof(struct in_addr); + break; + + case IPOPT_TS: + code = cp - (u_char *)ip; + ipt = (struct ip_timestamp *)cp; + if (ipt->ipt_len < 5) + goto bad; + if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) { + if (++ipt->ipt_oflw == 0) + goto bad; + break; + } + sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); + switch (ipt->ipt_flg) { + + case IPOPT_TS_TSONLY: + break; + + case IPOPT_TS_TSANDADDR: + if (ipt->ipt_ptr + sizeof(n_time) + + sizeof(struct in_addr) > ipt->ipt_len) + goto bad; + ipaddr.sin_addr = dst; + ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, + m->m_pkthdr.rcvif); + if (ia == 0) + continue; + (void)memcpy(sin, &IA_SIN(ia)->sin_addr, + sizeof(struct in_addr)); + ipt->ipt_ptr += sizeof(struct in_addr); + break; + + case IPOPT_TS_PRESPEC: + if (ipt->ipt_ptr + sizeof(n_time) + + sizeof(struct in_addr) > ipt->ipt_len) + goto bad; + (void)memcpy(&ipaddr.sin_addr, sin, + sizeof(struct in_addr)); + if (ifa_ifwithaddr((SA)&ipaddr) == 0) + continue; + ipt->ipt_ptr += sizeof(struct in_addr); + break; + + default: + goto bad; + } + ntime = iptime(); + (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, + sizeof(n_time)); + ipt->ipt_ptr += sizeof(n_time); + } + } + if (forward && ipforwarding) { + ip_forward(m, 1); + return (1); + } + return (0); +bad: +#ifdef _IP_VHL + ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ +#else + ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */ +#endif + icmp_error(m, type, code, 0, 0); + ipstat.ips_badoptions++; + return (1); +} + +/* + * Given address of next destination (final or next hop), + * return internet address info of interface to be used to get there. + */ +static struct in_ifaddr * +ip_rtaddr(struct in_addr dst) +{ + struct sockaddr_in *sin; + + sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; + + if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { + if (ipforward_rt.ro_rt) { + RTFREE(ipforward_rt.ro_rt); + ipforward_rt.ro_rt = 0; + } + sin->sin_family = AF_INET; + sin->sin_len = sizeof(*sin); + sin->sin_addr = dst; + + rtalloc_ign(&ipforward_rt, RTF_PRCLONING); + } + if (ipforward_rt.ro_rt == 0) + return ((struct in_ifaddr *)0); + return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); +} + +/* + * Save incoming source route for use in replies, + * to be picked up later by ip_srcroute if the receiver is interested. + */ +void +save_rte(u_char *option, struct in_addr dst) +{ + unsigned olen; + + olen = option[IPOPT_OLEN]; +#ifdef DIAGNOSTIC + if (ipprintfs) + printf("save_rte: olen %d\n", olen); +#endif + if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) + return; + bcopy(option, ip_srcrt.srcopt, olen); + ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); + ip_srcrt.dst = dst; +} + +/* + * Retrieve incoming source route for use in replies, + * in the same form used by setsockopt. + * The first hop is placed before the options, will be removed later. + */ +struct mbuf * +ip_srcroute(void) +{ + register struct in_addr *p, *q; + register struct mbuf *m; + + if (ip_nhops == 0) + return ((struct mbuf *)0); + m = m_get(M_DONTWAIT, MT_SOOPTS); + if (m == 0) + return ((struct mbuf *)0); + +#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) + + /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ + m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + + OPTSIZ; +#ifdef DIAGNOSTIC + if (ipprintfs) + printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); +#endif + + /* + * First save first hop for return route + */ + p = &ip_srcrt.route[ip_nhops - 1]; + *(mtod(m, struct in_addr *)) = *p--; +#ifdef DIAGNOSTIC + if (ipprintfs) + printf(" hops %"PRIx32, ntohl(mtod(m, struct in_addr *)->s_addr)); +#endif + + /* + * Copy option fields and padding (nop) to mbuf. + */ + ip_srcrt.nop = IPOPT_NOP; + ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; + (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), + &ip_srcrt.nop, OPTSIZ); + q = (struct in_addr *)(mtod(m, caddr_t) + + sizeof(struct in_addr) + OPTSIZ); +#undef OPTSIZ + /* + * Record return path as an IP source route, + * reversing the path (pointers are now aligned). + */ + while (p >= ip_srcrt.route) { +#ifdef DIAGNOSTIC + if (ipprintfs) + printf(" %"PRIx32, ntohl(q->s_addr)); +#endif + *q++ = *p--; + } + /* + * Last hop goes to final destination. + */ + *q = ip_srcrt.dst; +#ifdef DIAGNOSTIC + if (ipprintfs) + printf(" %"PRIx32"\n", ntohl(q->s_addr)); +#endif + return (m); +} + +/* + * Strip out IP options, at higher + * level protocol in the kernel. + * Second argument is buffer to which options + * will be moved, and return value is their length. + * XXX should be deleted; last arg currently ignored. + */ +void +ip_stripoptions(struct mbuf *m, struct mbuf *mopt) +{ + register int i; + struct ip *ip = mtod(m, struct ip *); + register caddr_t opts; + int olen; + +#ifdef _IP_VHL + olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); +#else + olen = (ip->ip_hl << 2) - sizeof (struct ip); +#endif + opts = (caddr_t)(ip + 1); + i = m->m_len - (sizeof (struct ip) + olen); + bcopy(opts + olen, opts, (unsigned)i); + m->m_len -= olen; + if (m->m_flags & M_PKTHDR) + m->m_pkthdr.len -= olen; +#ifdef _IP_VHL + ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); +#else + ip->ip_v = IPVERSION; + ip->ip_hl = (sizeof(struct ip) >> 2); +#endif +} + +u_char inetctlerrmap[PRC_NCMDS] = { + 0, 0, 0, 0, + 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, + EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, + EMSGSIZE, EHOSTUNREACH, 0, 0, + 0, 0, 0, 0, + ENOPROTOOPT +}; + +/* + * Forward a packet. If some error occurs return the sender + * an icmp packet. Note we can't always generate a meaningful + * icmp message because icmp doesn't have a large enough repertoire + * of codes and types. + * + * If not forwarding, just drop the packet. This could be confusing + * if ipforwarding was zero but some routing protocol was advancing + * us as a gateway to somewhere. However, we must let the routing + * protocol deal with that. + * + * The srcrt parameter indicates whether the packet is being forwarded + * via a source route. + */ +static void +ip_forward(struct mbuf *m, int srcrt) +{ + struct ip *ip = mtod(m, struct ip *); + register struct sockaddr_in *sin; + register struct rtentry *rt; + int error, type = 0, code = 0; + struct mbuf *mcopy; + n_long dest; + struct ifnet *destifp; + + dest = 0; +#ifdef DIAGNOSTIC + if (ipprintfs) + printf("forward: src %"PRIx32" dst %"PRIx32" ttl %x\n", + ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl); +#endif + + + if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { + ipstat.ips_cantforward++; + m_freem(m); + return; + } + HTONS(ip->ip_id); + if (ip->ip_ttl <= IPTTLDEC) { + icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); + return; + } + ip->ip_ttl -= IPTTLDEC; + + sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; + if ((rt = ipforward_rt.ro_rt) == 0 || + ip->ip_dst.s_addr != sin->sin_addr.s_addr) { + if (ipforward_rt.ro_rt) { + RTFREE(ipforward_rt.ro_rt); + ipforward_rt.ro_rt = 0; + } + sin->sin_family = AF_INET; + sin->sin_len = sizeof(*sin); + sin->sin_addr = ip->ip_dst; + + rtalloc_ign(&ipforward_rt, RTF_PRCLONING); + if (ipforward_rt.ro_rt == 0) { + icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); + return; + } + rt = ipforward_rt.ro_rt; + } + + /* + * Save at most 64 bytes of the packet in case + * we need to generate an ICMP message to the src. + */ + mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); + + /* + * If forwarding packet using same interface that it came in on, + * perhaps should send a redirect to sender to shortcut a hop. + * Only send redirect if source is sending directly to us, + * and if packet was not source routed (or has any options). + * Also, don't send redirect if forwarding using a default route + * or a route modified by a redirect. + */ +#define satosin(sa) ((struct sockaddr_in *)(sa)) + if (rt->rt_ifp == m->m_pkthdr.rcvif && + (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && + satosin(rt_key(rt))->sin_addr.s_addr != 0 && + ipsendredirects && !srcrt) { +#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) + u_long src = ntohl(ip->ip_src.s_addr); + + if (RTA(rt) && + (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { + if (rt->rt_flags & RTF_GATEWAY) + dest = satosin(rt->rt_gateway)->sin_addr.s_addr; + else + dest = ip->ip_dst.s_addr; + /* Router requirements says to only send host redirects */ + type = ICMP_REDIRECT; + code = ICMP_REDIRECT_HOST; + } + } + + error = ip_output(m, (struct mbuf *)0, &ipforward_rt, + IP_FORWARDING, 0); + if (error) + ipstat.ips_cantforward++; + else { + ipstat.ips_forward++; + if (type) + ipstat.ips_redirectsent++; + else { + if (mcopy) + m_freem(mcopy); + return; + } + } + if (mcopy == NULL) + return; + destifp = NULL; + + switch (error) { + + case 0: /* forwarded, but need redirect */ + /* type, code set above */ + break; + + case ENETUNREACH: /* shouldn't happen, checked above */ + case EHOSTUNREACH: + case ENETDOWN: + case EHOSTDOWN: + default: + type = ICMP_UNREACH; + code = ICMP_UNREACH_HOST; + break; + + case EMSGSIZE: + type = ICMP_UNREACH; + code = ICMP_UNREACH_NEEDFRAG; + if (ipforward_rt.ro_rt) + destifp = ipforward_rt.ro_rt->rt_ifp; + ipstat.ips_cantfrag++; + break; + + case ENOBUFS: + type = ICMP_SOURCEQUENCH; + code = 0; + break; + } + icmp_error(mcopy, type, code, dest, destifp); +} + +void +ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, + struct mbuf *m) +{ + if (inp->inp_socket->so_options & SO_TIMESTAMP) { + struct timeval tv; + + microtime(&tv); + *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), + SCM_TIMESTAMP, SOL_SOCKET); + if (*mp) + mp = &(*mp)->m_next; + } + if (inp->inp_flags & INP_RECVDSTADDR) { + *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, + sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); + if (*mp) + mp = &(*mp)->m_next; + } +#ifdef notyet + /* XXX + * Moving these out of udp_input() made them even more broken + * than they already were. + */ + /* options were tossed already */ + if (inp->inp_flags & INP_RECVOPTS) { + *mp = sbcreatecontrol((caddr_t) opts_deleted_above, + sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); + if (*mp) + mp = &(*mp)->m_next; + } + /* ip_srcroute doesn't do what we want here, need to fix */ + if (inp->inp_flags & INP_RECVRETOPTS) { + *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), + sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); + if (*mp) + mp = &(*mp)->m_next; + } +#endif + if (inp->inp_flags & INP_RECVIF) { + struct sockaddr_dl sdl; + + sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); + sdl.sdl_family = AF_LINK; + sdl.sdl_index = m->m_pkthdr.rcvif ? + m->m_pkthdr.rcvif->if_index : 0; + sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; + *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, + IP_RECVIF, IPPROTO_IP); + if (*mp) + mp = &(*mp)->m_next; + } +} + +int +ip_rsvp_init(struct socket *so) +{ + if (so->so_type != SOCK_RAW || + so->so_proto->pr_protocol != IPPROTO_RSVP) + return EOPNOTSUPP; + + if (ip_rsvpd != NULL) + return EADDRINUSE; + + ip_rsvpd = so; + /* + * This may seem silly, but we need to be sure we don't over-increment + * the RSVP counter, in case something slips up. + */ + if (!ip_rsvp_on) { + ip_rsvp_on = 1; + rsvp_on++; + } + + return 0; +} + +int +ip_rsvp_done(void) +{ + ip_rsvpd = NULL; + /* + * This may seem silly, but we need to be sure we don't over-decrement + * the RSVP counter, in case something slips up. + */ + if (ip_rsvp_on) { + ip_rsvp_on = 0; + rsvp_on--; + } + return 0; +} |