diff options
Diffstat (limited to 'freebsd/sys/netinet/ipfw/ip_fw_pfil.c')
| -rw-r--r-- | freebsd/sys/netinet/ipfw/ip_fw_pfil.c | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/freebsd/sys/netinet/ipfw/ip_fw_pfil.c b/freebsd/sys/netinet/ipfw/ip_fw_pfil.c new file mode 100644 index 00000000..8759f409 --- /dev/null +++ b/freebsd/sys/netinet/ipfw/ip_fw_pfil.c @@ -0,0 +1,417 @@ +#include <freebsd/machine/rtems-bsd-config.h> + +/*- + * Copyright (c) 2004 Andre Oppermann, Internet Business Solutions AG + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. + */ + +#include <freebsd/sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#if !defined(KLD_MODULE) +#include <freebsd/local/opt_ipfw.h> +#include <freebsd/local/opt_ipdn.h> +#include <freebsd/local/opt_inet.h> +#ifndef INET +#error IPFIREWALL requires INET. +#endif /* INET */ +#endif /* KLD_MODULE */ +#include <freebsd/local/opt_inet6.h> + +#include <freebsd/sys/param.h> +#include <freebsd/sys/systm.h> +#include <freebsd/sys/malloc.h> +#include <freebsd/sys/mbuf.h> +#include <freebsd/sys/module.h> +#include <freebsd/sys/kernel.h> +#include <freebsd/sys/lock.h> +#include <freebsd/sys/rwlock.h> +#include <freebsd/sys/socket.h> +#include <freebsd/sys/sysctl.h> + +#include <freebsd/net/if.h> +#include <freebsd/net/route.h> +#include <freebsd/net/pfil.h> +#include <freebsd/net/vnet.h> + +#include <freebsd/netinet/in.h> +#include <freebsd/netinet/in_systm.h> +#include <freebsd/netinet/ip.h> +#include <freebsd/netinet/ip_var.h> +#include <freebsd/netinet/ip_fw.h> +#include <freebsd/netinet/ipfw/ip_fw_private.h> +#include <freebsd/netgraph/ng_ipfw.h> + +#include <freebsd/machine/in_cksum.h> + +static VNET_DEFINE(int, fw_enable) = 1; +#define V_fw_enable VNET(fw_enable) + +#ifdef INET6 +static VNET_DEFINE(int, fw6_enable) = 1; +#define V_fw6_enable VNET(fw6_enable) +#endif + +int ipfw_chg_hook(SYSCTL_HANDLER_ARGS); + +/* Forward declarations. */ +static int ipfw_divert(struct mbuf **, int, struct ipfw_rule_ref *, int); + +#ifdef SYSCTL_NODE + +SYSBEGIN(f1) + +SYSCTL_DECL(_net_inet_ip_fw); +SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, enable, + CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_enable), 0, + ipfw_chg_hook, "I", "Enable ipfw"); +#ifdef INET6 +SYSCTL_DECL(_net_inet6_ip6_fw); +SYSCTL_VNET_PROC(_net_inet6_ip6_fw, OID_AUTO, enable, + CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw6_enable), 0, + ipfw_chg_hook, "I", "Enable ipfw+6"); +#endif /* INET6 */ + +SYSEND + +#endif /* SYSCTL_NODE */ + +/* + * The pfilter hook to pass packets to ipfw_chk and then to + * dummynet, divert, netgraph or other modules. + * The packet may be consumed. + */ +int +ipfw_check_hook(void *arg, struct mbuf **m0, struct ifnet *ifp, int dir, + struct inpcb *inp) +{ + struct ip_fw_args args; + struct m_tag *tag; + int ipfw; + int ret; + + /* all the processing now uses ip_len in net format */ + if (mtod(*m0, struct ip *)->ip_v == 4) + SET_NET_IPLEN(mtod(*m0, struct ip *)); + + /* convert dir to IPFW values */ + dir = (dir == PFIL_IN) ? DIR_IN : DIR_OUT; + bzero(&args, sizeof(args)); + +again: + /* + * extract and remove the tag if present. If we are left + * with onepass, optimize the outgoing path. + */ + tag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL); + if (tag != NULL) { + args.rule = *((struct ipfw_rule_ref *)(tag+1)); + m_tag_delete(*m0, tag); + if (args.rule.info & IPFW_ONEPASS) { + SET_HOST_IPLEN(mtod(*m0, struct ip *)); + return 0; + } + } + + args.m = *m0; + args.oif = dir == DIR_OUT ? ifp : NULL; + args.inp = inp; + + ipfw = ipfw_chk(&args); + *m0 = args.m; + + KASSERT(*m0 != NULL || ipfw == IP_FW_DENY, ("%s: m0 is NULL", + __func__)); + + /* breaking out of the switch means drop */ + ret = 0; /* default return value for pass */ + switch (ipfw) { + case IP_FW_PASS: + /* next_hop may be set by ipfw_chk */ + if (args.next_hop == NULL) + break; /* pass */ +#ifndef IPFIREWALL_FORWARD + ret = EACCES; +#else + { + struct m_tag *fwd_tag; + + /* Incoming packets should not be tagged so we do not + * m_tag_find. Outgoing packets may be tagged, so we + * reuse the tag if present. + */ + fwd_tag = (dir == DIR_IN) ? NULL : + m_tag_find(*m0, PACKET_TAG_IPFORWARD, NULL); + if (fwd_tag != NULL) { + m_tag_unlink(*m0, fwd_tag); + } else { + fwd_tag = m_tag_get(PACKET_TAG_IPFORWARD, + sizeof(struct sockaddr_in), M_NOWAIT); + if (fwd_tag == NULL) { + ret = EACCES; + break; /* i.e. drop */ + } + } + bcopy(args.next_hop, (fwd_tag+1), sizeof(struct sockaddr_in)); + m_tag_prepend(*m0, fwd_tag); + + if (in_localip(args.next_hop->sin_addr)) + (*m0)->m_flags |= M_FASTFWD_OURS; + } +#endif + break; + + case IP_FW_DENY: + ret = EACCES; + break; /* i.e. drop */ + + case IP_FW_DUMMYNET: + ret = EACCES; + if (ip_dn_io_ptr == NULL) + break; /* i.e. drop */ + if (mtod(*m0, struct ip *)->ip_v == 4) + ret = ip_dn_io_ptr(m0, dir, &args); + else if (mtod(*m0, struct ip *)->ip_v == 6) + ret = ip_dn_io_ptr(m0, dir | PROTO_IPV6, &args); + else + break; /* drop it */ + /* + * XXX should read the return value. + * dummynet normally eats the packet and sets *m0=NULL + * unless the packet can be sent immediately. In this + * case args is updated and we should re-run the + * check without clearing args. + */ + if (*m0 != NULL) + goto again; + break; + + case IP_FW_TEE: + case IP_FW_DIVERT: + if (ip_divert_ptr == NULL) { + ret = EACCES; + break; /* i.e. drop */ + } + ret = ipfw_divert(m0, dir, &args.rule, + (ipfw == IP_FW_TEE) ? 1 : 0); + /* continue processing for the original packet (tee). */ + if (*m0) + goto again; + break; + + case IP_FW_NGTEE: + case IP_FW_NETGRAPH: + if (ng_ipfw_input_p == NULL) { + ret = EACCES; + break; /* i.e. drop */ + } + ret = ng_ipfw_input_p(m0, dir, &args, + (ipfw == IP_FW_NGTEE) ? 1 : 0); + if (ipfw == IP_FW_NGTEE) /* ignore errors for NGTEE */ + goto again; /* continue with packet */ + break; + + case IP_FW_NAT: + /* honor one-pass in case of successful nat */ + if (V_fw_one_pass) + break; /* ret is already 0 */ + goto again; + + case IP_FW_REASS: + goto again; /* continue with packet */ + + default: + KASSERT(0, ("%s: unknown retval", __func__)); + } + + if (ret != 0) { + if (*m0) + FREE_PKT(*m0); + *m0 = NULL; + } + if (*m0 && mtod(*m0, struct ip *)->ip_v == 4) + SET_HOST_IPLEN(mtod(*m0, struct ip *)); + return ret; +} + +/* do the divert, return 1 on error 0 on success */ +static int +ipfw_divert(struct mbuf **m0, int incoming, struct ipfw_rule_ref *rule, + int tee) +{ + /* + * ipfw_chk() has already tagged the packet with the divert tag. + * If tee is set, copy packet and return original. + * If not tee, consume packet and send it to divert socket. + */ + struct mbuf *clone; + struct ip *ip; + struct m_tag *tag; + + /* Cloning needed for tee? */ + if (tee == 0) { + clone = *m0; /* use the original mbuf */ + *m0 = NULL; + } else { + clone = m_dup(*m0, M_DONTWAIT); + /* If we cannot duplicate the mbuf, we sacrifice the divert + * chain and continue with the tee-ed packet. + */ + if (clone == NULL) + return 1; + } + + /* + * Divert listeners can normally handle non-fragmented packets, + * but we can only reass in the non-tee case. + * This means that listeners on a tee rule may get fragments, + * and have to live with that. + * Note that we now have the 'reass' ipfw option so if we care + * we can do it before a 'tee'. + */ + ip = mtod(clone, struct ip *); + if (!tee && ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) { + int hlen; + struct mbuf *reass; + + SET_HOST_IPLEN(ip); /* ip_reass wants host order */ + reass = ip_reass(clone); /* Reassemble packet. */ + if (reass == NULL) + return 0; /* not an error */ + /* if reass = NULL then it was consumed by ip_reass */ + /* + * IP header checksum fixup after reassembly and leave header + * in network byte order. + */ + ip = mtod(reass, struct ip *); + hlen = ip->ip_hl << 2; + SET_NET_IPLEN(ip); + ip->ip_sum = 0; + if (hlen == sizeof(struct ip)) + ip->ip_sum = in_cksum_hdr(ip); + else + ip->ip_sum = in_cksum(reass, hlen); + clone = reass; + } + /* attach a tag to the packet with the reinject info */ + tag = m_tag_alloc(MTAG_IPFW_RULE, 0, + sizeof(struct ipfw_rule_ref), M_NOWAIT); + if (tag == NULL) { + FREE_PKT(clone); + return 1; + } + *((struct ipfw_rule_ref *)(tag+1)) = *rule; + m_tag_prepend(clone, tag); + + /* Do the dirty job... */ + ip_divert_ptr(clone, incoming); + return 0; +} + +/* + * attach or detach hooks for a given protocol family + */ +static int +ipfw_hook(int onoff, int pf) +{ + struct pfil_head *pfh; + + pfh = pfil_head_get(PFIL_TYPE_AF, pf); + if (pfh == NULL) + return ENOENT; + + (void) (onoff ? pfil_add_hook : pfil_remove_hook) + (ipfw_check_hook, NULL, PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh); + + return 0; +} + +int +ipfw_attach_hooks(int arg) +{ + int error = 0; + + if (arg == 0) /* detach */ + ipfw_hook(0, AF_INET); + else if (V_fw_enable && ipfw_hook(1, AF_INET) != 0) { + error = ENOENT; /* see ip_fw_pfil.c::ipfw_hook() */ + printf("ipfw_hook() error\n"); + } +#ifdef INET6 + if (arg == 0) /* detach */ + ipfw_hook(0, AF_INET6); + else if (V_fw6_enable && ipfw_hook(1, AF_INET6) != 0) { + error = ENOENT; + printf("ipfw6_hook() error\n"); + } +#endif + return error; +} + +int +ipfw_chg_hook(SYSCTL_HANDLER_ARGS) +{ + int enable; + int oldenable; + int error; + int af; + + if (arg1 == &VNET_NAME(fw_enable)) { + enable = V_fw_enable; + af = AF_INET; + } +#ifdef INET6 + else if (arg1 == &VNET_NAME(fw6_enable)) { + enable = V_fw6_enable; + af = AF_INET6; + } +#endif + else + return (EINVAL); + + oldenable = enable; + + error = sysctl_handle_int(oidp, &enable, 0, req); + + if (error) + return (error); + + enable = (enable) ? 1 : 0; + + if (enable == oldenable) + return (0); + + error = ipfw_hook(enable, af); + if (error) + return (error); + if (af == AF_INET) + V_fw_enable = enable; +#ifdef INET6 + else if (af == AF_INET6) + V_fw6_enable = enable; +#endif + + return (0); +} +/* end of file */ |