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>
62 #include <netinet/ipfw/ip_fw_private.h>
63 #include <netgraph/ng_ipfw.h>
65 #include <machine/in_cksum.h>
67 static VNET_DEFINE(int, fw_enable) = 1;
68 #define V_fw_enable VNET(fw_enable)
71 static VNET_DEFINE(int, fw6_enable) = 1;
72 #define V_fw6_enable VNET(fw6_enable)
75 int ipfw_chg_hook(SYSCTL_HANDLER_ARGS);
77 /* Forward declarations. */
78 static int ipfw_divert(struct mbuf **, int, struct ipfw_rule_ref *, int);
84 SYSCTL_DECL(_net_inet_ip_fw);
85 SYSCTL_VNET_PROC(_net_inet_ip_fw, OID_AUTO, enable,
86 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw_enable), 0,
87 ipfw_chg_hook, "I", "Enable ipfw");
89 SYSCTL_DECL(_net_inet6_ip6_fw);
90 SYSCTL_VNET_PROC(_net_inet6_ip6_fw, OID_AUTO, enable,
91 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, &VNET_NAME(fw6_enable), 0,
92 ipfw_chg_hook, "I", "Enable ipfw+6");
97 #endif /* SYSCTL_NODE */
100 * The pfilter hook to pass packets to ipfw_chk and then to
101 * dummynet, divert, netgraph or other modules.
102 * The packet may be consumed.
105 ipfw_check_hook(void *arg, struct mbuf **m0, struct ifnet *ifp, int dir,
108 struct ip_fw_args args;
113 /* all the processing now uses ip_len in net format */
114 if (mtod(*m0, struct ip *)->ip_v == 4)
115 SET_NET_IPLEN(mtod(*m0, struct ip *));
117 /* convert dir to IPFW values */
118 dir = (dir == PFIL_IN) ? DIR_IN : DIR_OUT;
119 bzero(&args, sizeof(args));
123 * extract and remove the tag if present. If we are left
124 * with onepass, optimize the outgoing path.
126 tag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL);
128 args.rule = *((struct ipfw_rule_ref *)(tag+1));
129 m_tag_delete(*m0, tag);
130 if (args.rule.info & IPFW_ONEPASS) {
131 if (mtod(*m0, struct ip *)->ip_v == 4)
132 SET_HOST_IPLEN(mtod(*m0, struct ip *));
138 args.oif = dir == DIR_OUT ? ifp : NULL;
141 ipfw = ipfw_chk(&args);
144 KASSERT(*m0 != NULL || ipfw == IP_FW_DENY, ("%s: m0 is NULL",
147 /* breaking out of the switch means drop */
148 ret = 0; /* default return value for pass */
151 /* next_hop may be set by ipfw_chk */
152 if (args.next_hop == NULL && args.next_hop6 == NULL)
154 #if !defined(IPFIREWALL_FORWARD) || (!defined(INET6) && !defined(INET))
158 struct m_tag *fwd_tag;
161 KASSERT(args.next_hop == NULL || args.next_hop6 == NULL,
162 ("%s: both next_hop=%p and next_hop6=%p not NULL", __func__,
163 args.next_hop, args.next_hop6));
165 if (args.next_hop6 != NULL)
166 len = sizeof(struct sockaddr_in6);
169 if (args.next_hop != NULL)
170 len = sizeof(struct sockaddr_in);
173 /* Incoming packets should not be tagged so we do not
174 * m_tag_find. Outgoing packets may be tagged, so we
175 * reuse the tag if present.
177 fwd_tag = (dir == DIR_IN) ? NULL :
178 m_tag_find(*m0, PACKET_TAG_IPFORWARD, NULL);
179 if (fwd_tag != NULL) {
180 m_tag_unlink(*m0, fwd_tag);
182 fwd_tag = m_tag_get(PACKET_TAG_IPFORWARD, len,
184 if (fwd_tag == NULL) {
186 break; /* i.e. drop */
190 if (args.next_hop6 != NULL) {
191 bcopy(args.next_hop6, (fwd_tag+1), len);
192 if (in6_localip(&args.next_hop6->sin6_addr))
193 (*m0)->m_flags |= M_FASTFWD_OURS;
197 if (args.next_hop != NULL) {
198 bcopy(args.next_hop, (fwd_tag+1), len);
199 if (in_localip(args.next_hop->sin_addr))
200 (*m0)->m_flags |= M_FASTFWD_OURS;
203 m_tag_prepend(*m0, fwd_tag);
205 #endif /* IPFIREWALL_FORWARD */
210 break; /* i.e. drop */
214 if (ip_dn_io_ptr == NULL)
215 break; /* i.e. drop */
216 if (mtod(*m0, struct ip *)->ip_v == 4)
217 ret = ip_dn_io_ptr(m0, dir, &args);
218 else if (mtod(*m0, struct ip *)->ip_v == 6)
219 ret = ip_dn_io_ptr(m0, dir | PROTO_IPV6, &args);
223 * XXX should read the return value.
224 * dummynet normally eats the packet and sets *m0=NULL
225 * unless the packet can be sent immediately. In this
226 * case args is updated and we should re-run the
227 * check without clearing args.
235 if (ip_divert_ptr == NULL) {
237 break; /* i.e. drop */
239 ret = ipfw_divert(m0, dir, &args.rule,
240 (ipfw == IP_FW_TEE) ? 1 : 0);
241 /* continue processing for the original packet (tee). */
248 if (ng_ipfw_input_p == NULL) {
250 break; /* i.e. drop */
252 ret = ng_ipfw_input_p(m0, dir, &args,
253 (ipfw == IP_FW_NGTEE) ? 1 : 0);
254 if (ipfw == IP_FW_NGTEE) /* ignore errors for NGTEE */
255 goto again; /* continue with packet */
259 /* honor one-pass in case of successful nat */
261 break; /* ret is already 0 */
265 goto again; /* continue with packet */
268 KASSERT(0, ("%s: unknown retval", __func__));
276 if (*m0 && mtod(*m0, struct ip *)->ip_v == 4)
277 SET_HOST_IPLEN(mtod(*m0, struct ip *));
281 /* do the divert, return 1 on error 0 on success */
283 ipfw_divert(struct mbuf **m0, int incoming, struct ipfw_rule_ref *rule,
287 * ipfw_chk() has already tagged the packet with the divert tag.
288 * If tee is set, copy packet and return original.
289 * If not tee, consume packet and send it to divert socket.
292 struct ip *ip = mtod(*m0, struct ip *);
295 /* Cloning needed for tee? */
297 clone = *m0; /* use the original mbuf */
300 clone = m_dup(*m0, M_DONTWAIT);
301 /* If we cannot duplicate the mbuf, we sacrifice the divert
302 * chain and continue with the tee-ed packet.
309 * Divert listeners can normally handle non-fragmented packets,
310 * but we can only reass in the non-tee case.
311 * This means that listeners on a tee rule may get fragments,
312 * and have to live with that.
313 * Note that we now have the 'reass' ipfw option so if we care
314 * we can do it before a 'tee'.
316 if (!tee) switch (ip->ip_v) {
318 if (ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) {
322 SET_HOST_IPLEN(ip); /* ip_reass wants host order */
323 reass = ip_reass(clone); /* Reassemble packet. */
325 return 0; /* not an error */
326 /* if reass = NULL then it was consumed by ip_reass */
328 * IP header checksum fixup after reassembly and leave header
329 * in network byte order.
331 ip = mtod(reass, struct ip *);
332 hlen = ip->ip_hl << 2;
335 if (hlen == sizeof(struct ip))
336 ip->ip_sum = in_cksum_hdr(ip);
338 ip->ip_sum = in_cksum(reass, hlen);
343 case IPV6_VERSION >> 4:
345 struct ip6_hdr *const ip6 = mtod(clone, struct ip6_hdr *);
347 if (ip6->ip6_nxt == IPPROTO_FRAGMENT) {
350 off = sizeof(struct ip6_hdr);
351 nxt = frag6_input(&clone, &off, 0);
352 if (nxt == IPPROTO_DONE)
360 /* attach a tag to the packet with the reinject info */
361 tag = m_tag_alloc(MTAG_IPFW_RULE, 0,
362 sizeof(struct ipfw_rule_ref), M_NOWAIT);
367 *((struct ipfw_rule_ref *)(tag+1)) = *rule;
368 m_tag_prepend(clone, tag);
370 /* Do the dirty job... */
371 ip_divert_ptr(clone, incoming);
376 * attach or detach hooks for a given protocol family
379 ipfw_hook(int onoff, int pf)
381 struct pfil_head *pfh;
383 pfh = pfil_head_get(PFIL_TYPE_AF, pf);
387 (void) (onoff ? pfil_add_hook : pfil_remove_hook)
388 (ipfw_check_hook, NULL, PFIL_IN | PFIL_OUT | PFIL_WAITOK, pfh);
394 ipfw_attach_hooks(int arg)
398 if (arg == 0) /* detach */
399 ipfw_hook(0, AF_INET);
400 else if (V_fw_enable && ipfw_hook(1, AF_INET) != 0) {
401 error = ENOENT; /* see ip_fw_pfil.c::ipfw_hook() */
402 printf("ipfw_hook() error\n");
405 if (arg == 0) /* detach */
406 ipfw_hook(0, AF_INET6);
407 else if (V_fw6_enable && ipfw_hook(1, AF_INET6) != 0) {
409 printf("ipfw6_hook() error\n");
416 ipfw_chg_hook(SYSCTL_HANDLER_ARGS)
423 if (arg1 == &VNET_NAME(fw_enable)) {
424 enable = V_fw_enable;
428 else if (arg1 == &VNET_NAME(fw6_enable)) {
429 enable = V_fw6_enable;
438 error = sysctl_handle_int(oidp, &enable, 0, req);
443 enable = (enable) ? 1 : 0;
445 if (enable == oldenable)
448 error = ipfw_hook(enable, af);
452 V_fw_enable = enable;
454 else if (af == AF_INET6)
455 V_fw6_enable = enable;