2 * Copyright (c) 2004 Andre Oppermann, Internet Business Solutions AG
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
32 #include "opt_inet6.h"
34 #error IPFIREWALL requires INET.
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
41 #include <sys/module.h>
42 #include <sys/kernel.h>
44 #include <sys/rwlock.h>
45 #include <sys/socket.h>
46 #include <sys/sysctl.h>
49 #include <net/route.h>
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/ip_fw.h>
59 #include <netinet/ip6.h>
60 #include <netinet6/ip6_var.h>
63 #include <netgraph/ng_ipfw.h>
65 #include <netpfil/ipfw/ip_fw_private.h>
67 #include <machine/in_cksum.h>
69 static VNET_DEFINE(int, fw_enable) = 1;
70 #define V_fw_enable VNET(fw_enable)
73 static VNET_DEFINE(int, fw6_enable) = 1;
74 #define V_fw6_enable VNET(fw6_enable)
77 int ipfw_chg_hook(SYSCTL_HANDLER_ARGS);
79 /* Forward declarations. */
80 static int ipfw_divert(struct mbuf **, int, struct ipfw_rule_ref *, int);
86 SYSCTL_DECL(_net_inet_ip_fw);
87 SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, enable,
88 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_enable), 0,
89 ipfw_chg_hook, "I", "Enable ipfw");
91 SYSCTL_DECL(_net_inet6_ip6_fw);
92 SYSCTL_VNET_PROC(_net_inet6_ip6_fw, OID_AUTO, enable,
93 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw6_enable), 0,
94 ipfw_chg_hook, "I", "Enable ipfw+6");
99 #endif /* SYSCTL_NODE */
102 * The pfilter hook to pass packets to ipfw_chk and then to
103 * dummynet, divert, netgraph or other modules.
104 * The packet may be consumed.
107 ipfw_check_hook(void *arg, struct mbuf **m0, struct ifnet *ifp, int dir,
110 struct ip_fw_args args;
115 /* all the processing now uses ip_len in net format */
116 if (mtod(*m0, struct ip *)->ip_v == 4)
117 SET_NET_IPLEN(mtod(*m0, struct ip *));
119 /* convert dir to IPFW values */
120 dir = (dir == PFIL_IN) ? DIR_IN : DIR_OUT;
121 bzero(&args, sizeof(args));
125 * extract and remove the tag if present. If we are left
126 * with onepass, optimize the outgoing path.
128 tag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL);
130 args.rule = *((struct ipfw_rule_ref *)(tag+1));
131 m_tag_delete(*m0, tag);
132 if (args.rule.info & IPFW_ONEPASS) {
133 if (mtod(*m0, struct ip *)->ip_v == 4)
134 SET_HOST_IPLEN(mtod(*m0, struct ip *));
140 args.oif = dir == DIR_OUT ? ifp : NULL;
143 ipfw = ipfw_chk(&args);
146 KASSERT(*m0 != NULL || ipfw == IP_FW_DENY, ("%s: m0 is NULL",
149 /* breaking out of the switch means drop */
150 ret = 0; /* default return value for pass */
153 /* next_hop may be set by ipfw_chk */
154 if (args.next_hop == NULL && args.next_hop6 == NULL)
156 #if (!defined(INET6) && !defined(INET))
160 struct m_tag *fwd_tag;
163 KASSERT(args.next_hop == NULL || args.next_hop6 == NULL,
164 ("%s: both next_hop=%p and next_hop6=%p not NULL", __func__,
165 args.next_hop, args.next_hop6));
167 if (args.next_hop6 != NULL)
168 len = sizeof(struct sockaddr_in6);
171 if (args.next_hop != NULL)
172 len = sizeof(struct sockaddr_in);
175 /* Incoming packets should not be tagged so we do not
176 * m_tag_find. Outgoing packets may be tagged, so we
177 * reuse the tag if present.
179 fwd_tag = (dir == DIR_IN) ? NULL :
180 m_tag_find(*m0, PACKET_TAG_IPFORWARD, NULL);
181 if (fwd_tag != NULL) {
182 m_tag_unlink(*m0, fwd_tag);
184 fwd_tag = m_tag_get(PACKET_TAG_IPFORWARD, len,
186 if (fwd_tag == NULL) {
188 break; /* i.e. drop */
192 if (args.next_hop6 != NULL) {
193 bcopy(args.next_hop6, (fwd_tag+1), len);
194 if (in6_localip(&args.next_hop6->sin6_addr))
195 (*m0)->m_flags |= M_FASTFWD_OURS;
196 (*m0)->m_flags |= M_IP6_NEXTHOP;
200 if (args.next_hop != NULL) {
201 bcopy(args.next_hop, (fwd_tag+1), len);
202 if (in_localip(args.next_hop->sin_addr))
203 (*m0)->m_flags |= M_FASTFWD_OURS;
204 (*m0)->m_flags |= M_IP_NEXTHOP;
207 m_tag_prepend(*m0, fwd_tag);
209 #endif /* INET || INET6 */
214 break; /* i.e. drop */
218 if (ip_dn_io_ptr == NULL)
219 break; /* i.e. drop */
220 if (mtod(*m0, struct ip *)->ip_v == 4)
221 ret = ip_dn_io_ptr(m0, dir, &args);
222 else if (mtod(*m0, struct ip *)->ip_v == 6)
223 ret = ip_dn_io_ptr(m0, dir | PROTO_IPV6, &args);
227 * XXX should read the return value.
228 * dummynet normally eats the packet and sets *m0=NULL
229 * unless the packet can be sent immediately. In this
230 * case args is updated and we should re-run the
231 * check without clearing args.
239 if (ip_divert_ptr == NULL) {
241 break; /* i.e. drop */
243 ret = ipfw_divert(m0, dir, &args.rule,
244 (ipfw == IP_FW_TEE) ? 1 : 0);
245 /* continue processing for the original packet (tee). */
252 if (ng_ipfw_input_p == NULL) {
254 break; /* i.e. drop */
256 ret = ng_ipfw_input_p(m0, dir, &args,
257 (ipfw == IP_FW_NGTEE) ? 1 : 0);
258 if (ipfw == IP_FW_NGTEE) /* ignore errors for NGTEE */
259 goto again; /* continue with packet */
263 /* honor one-pass in case of successful nat */
265 break; /* ret is already 0 */
269 goto again; /* continue with packet */
272 KASSERT(0, ("%s: unknown retval", __func__));
280 if (*m0 && mtod(*m0, struct ip *)->ip_v == 4)
281 SET_HOST_IPLEN(mtod(*m0, struct ip *));
285 /* do the divert, return 1 on error 0 on success */
287 ipfw_divert(struct mbuf **m0, int incoming, struct ipfw_rule_ref *rule,
291 * ipfw_chk() has already tagged the packet with the divert tag.
292 * If tee is set, copy packet and return original.
293 * If not tee, consume packet and send it to divert socket.
296 struct ip *ip = mtod(*m0, struct ip *);
299 /* Cloning needed for tee? */
301 clone = *m0; /* use the original mbuf */
304 clone = m_dup(*m0, M_DONTWAIT);
305 /* If we cannot duplicate the mbuf, we sacrifice the divert
306 * chain and continue with the tee-ed packet.
313 * Divert listeners can normally handle non-fragmented packets,
314 * but we can only reass in the non-tee case.
315 * This means that listeners on a tee rule may get fragments,
316 * and have to live with that.
317 * Note that we now have the 'reass' ipfw option so if we care
318 * we can do it before a 'tee'.
320 if (!tee) switch (ip->ip_v) {
322 if (ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) {
326 SET_HOST_IPLEN(ip); /* ip_reass wants host order */
327 reass = ip_reass(clone); /* Reassemble packet. */
329 return 0; /* not an error */
330 /* if reass = NULL then it was consumed by ip_reass */
332 * IP header checksum fixup after reassembly and leave header
333 * in network byte order.
335 ip = mtod(reass, struct ip *);
336 hlen = ip->ip_hl << 2;
339 if (hlen == sizeof(struct ip))
340 ip->ip_sum = in_cksum_hdr(ip);
342 ip->ip_sum = in_cksum(reass, hlen);
347 case IPV6_VERSION >> 4:
349 struct ip6_hdr *const ip6 = mtod(clone, struct ip6_hdr *);
351 if (ip6->ip6_nxt == IPPROTO_FRAGMENT) {
354 off = sizeof(struct ip6_hdr);
355 nxt = frag6_input(&clone, &off, 0);
356 if (nxt == IPPROTO_DONE)
364 /* attach a tag to the packet with the reinject info */
365 tag = m_tag_alloc(MTAG_IPFW_RULE, 0,
366 sizeof(struct ipfw_rule_ref), M_NOWAIT);
371 *((struct ipfw_rule_ref *)(tag+1)) = *rule;
372 m_tag_prepend(clone, tag);
374 /* Do the dirty job... */
375 ip_divert_ptr(clone, incoming);
380 * attach or detach hooks for a given protocol family
383 ipfw_hook(int onoff, int pf)
385 struct pfil_head *pfh;
387 pfh = pfil_head_get(PFIL_TYPE_AF, pf);
391 (void) (onoff ? pfil_add_hook : pfil_remove_hook)
392 (ipfw_check_hook, NULL, PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh);
398 ipfw_attach_hooks(int arg)
402 if (arg == 0) /* detach */
403 ipfw_hook(0, AF_INET);
404 else if (V_fw_enable && ipfw_hook(1, AF_INET) != 0) {
405 error = ENOENT; /* see ip_fw_pfil.c::ipfw_hook() */
406 printf("ipfw_hook() error\n");
409 if (arg == 0) /* detach */
410 ipfw_hook(0, AF_INET6);
411 else if (V_fw6_enable && ipfw_hook(1, AF_INET6) != 0) {
413 printf("ipfw6_hook() error\n");
420 ipfw_chg_hook(SYSCTL_HANDLER_ARGS)
427 if (arg1 == &VNET_NAME(fw_enable)) {
428 enable = V_fw_enable;
432 else if (arg1 == &VNET_NAME(fw6_enable)) {
433 enable = V_fw6_enable;
442 error = sysctl_handle_int(oidp, &enable, 0, req);
447 enable = (enable) ? 1 : 0;
449 if (enable == oldenable)
452 error = ipfw_hook(enable, af);
456 V_fw_enable = enable;
458 else if (af == AF_INET6)
459 V_fw6_enable = enable;