2 * Copyright (c) 2014-2016 Andrey V. Elsukov <ae@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include "opt_inet6.h"
31 #include "opt_ipstealth.h"
33 #include <sys/param.h>
34 #include <sys/systm.h>
36 #include <sys/socket.h>
37 #include <sys/kernel.h>
38 #include <sys/sysctl.h>
41 #include <net/if_var.h>
42 #include <net/route.h>
46 #include <netinet/in.h>
47 #include <netinet/in_kdtrace.h>
48 #include <netinet/in_var.h>
49 #include <netinet/ip_var.h>
50 #include <netinet/ip6.h>
51 #include <netinet/icmp6.h>
52 #include <netinet6/in6_var.h>
53 #include <netinet6/in6_fib.h>
54 #include <netinet6/ip6_var.h>
55 #include <netinet6/nd6.h>
58 ip6_findroute(struct nhop6_basic *pnh, const struct sockaddr_in6 *dst,
62 if (fib6_lookup_nh_basic(M_GETFIB(m), &dst->sin6_addr,
63 dst->sin6_scope_id, 0, dst->sin6_flowinfo, pnh) != 0) {
64 IP6STAT_INC(ip6s_noroute);
65 IP6STAT_INC(ip6s_cantforward);
66 icmp6_error(m, ICMP6_DST_UNREACH,
67 ICMP6_DST_UNREACH_NOROUTE, 0);
68 return (EHOSTUNREACH);
70 if (pnh->nh_flags & NHF_BLACKHOLE) {
71 IP6STAT_INC(ip6s_cantforward);
73 return (EHOSTUNREACH);
76 if (pnh->nh_flags & NHF_REJECT) {
77 IP6STAT_INC(ip6s_cantforward);
78 icmp6_error(m, ICMP6_DST_UNREACH,
79 ICMP6_DST_UNREACH_REJECT, 0);
80 return (EHOSTUNREACH);
86 ip6_tryforward(struct mbuf *m)
88 struct sockaddr_in6 dst;
89 struct nhop6_basic nh;
90 struct m_tag *fwd_tag;
97 * Fallback conditions to ip6_input for slow path processing.
99 ip6 = mtod(m, struct ip6_hdr *);
100 if (ip6->ip6_nxt == IPPROTO_HOPOPTS ||
101 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
102 IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst) ||
103 IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src) ||
104 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) ||
105 in6_localip(&ip6->ip6_dst))
108 * Check that the amount of data in the buffers
109 * is as at least much as the IPv6 header would have us expect.
110 * Trim mbufs if longer than we expect.
111 * Drop packet if shorter than we expect.
113 rcvif = m->m_pkthdr.rcvif;
114 plen = ntohs(ip6->ip6_plen);
117 * Jumbograms must have hop-by-hop header and go via
120 IP6STAT_INC(ip6s_badoptions);
123 if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
124 IP6STAT_INC(ip6s_tooshort);
125 in6_ifstat_inc(rcvif, ifs6_in_truncated);
128 if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
129 if (m->m_len == m->m_pkthdr.len) {
130 m->m_len = sizeof(struct ip6_hdr) + plen;
131 m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
133 m_adj(m, sizeof(struct ip6_hdr) + plen -
143 if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
144 icmp6_error(m, ICMP6_TIME_EXCEEDED,
145 ICMP6_TIME_EXCEED_TRANSIT, 0);
150 bzero(&dst, sizeof(dst));
151 dst.sin6_family = AF_INET6;
152 dst.sin6_len = sizeof(dst);
153 dst.sin6_addr = ip6->ip6_dst;
156 * Incoming packet firewall processing.
158 if (!PFIL_HOOKED(&V_inet6_pfil_hook))
160 if (pfil_run_hooks(&V_inet6_pfil_hook, &m, rcvif, PFIL_IN,
161 NULL) != 0 || m == NULL)
164 * If packet filter sets the M_FASTFWD_OURS flag, this means
165 * that new destination or next hop is our local address.
166 * So, we can just go back to ip6_input.
167 * XXX: should we decrement ip6_hlim in such case?
169 * Also it can forward packet to another destination, e.g.
170 * M_IP6_NEXTHOP flag is set and fwd_tag is attached to mbuf.
172 if (m->m_flags & M_FASTFWD_OURS)
175 ip6 = mtod(m, struct ip6_hdr *);
176 if ((m->m_flags & M_IP6_NEXTHOP) &&
177 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
179 * Now we will find route to forwarded by pfil destination.
181 bcopy((fwd_tag + 1), &dst, sizeof(dst));
182 m->m_flags &= ~M_IP6_NEXTHOP;
183 m_tag_delete(m, fwd_tag);
185 /* Update dst since pfil could change it */
186 dst.sin6_addr = ip6->ip6_dst;
190 * Find route to destination.
192 if (ip6_findroute(&nh, &dst, m) != 0) {
194 in6_ifstat_inc(rcvif, ifs6_in_noroute);
198 * We used slow path processing for packets with scoped addresses.
199 * So, scope checks aren't needed here.
201 if (m->m_pkthdr.len > nh.nh_mtu) {
202 in6_ifstat_inc(nh.nh_ifp, ifs6_in_toobig);
203 icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, nh.nh_mtu);
209 * Outgoing packet firewall processing.
211 if (!PFIL_HOOKED(&V_inet6_pfil_hook))
213 if (pfil_run_hooks(&V_inet6_pfil_hook, &m, nh.nh_ifp, PFIL_OUT,
214 NULL) != 0 || m == NULL)
217 * If packet filter sets the M_FASTFWD_OURS flag, this means
218 * that new destination or next hop is our local address.
219 * So, we can just go back to ip6_input.
221 * Also it can forward packet to another destination, e.g.
222 * M_IP6_NEXTHOP flag is set and fwd_tag is attached to mbuf.
224 if (m->m_flags & M_FASTFWD_OURS) {
226 * XXX: we did one hop and should decrement hop limit. But
227 * now we are the destination and just don't pay attention.
232 * Again. A packet filter could change the destination address.
234 ip6 = mtod(m, struct ip6_hdr *);
235 if (m->m_flags & M_IP6_NEXTHOP)
236 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
240 if (fwd_tag != NULL ||
241 !IN6_ARE_ADDR_EQUAL(&dst.sin6_addr, &ip6->ip6_dst)) {
242 if (fwd_tag != NULL) {
243 bcopy((fwd_tag + 1), &dst, sizeof(dst));
244 m->m_flags &= ~M_IP6_NEXTHOP;
245 m_tag_delete(m, fwd_tag);
247 dst.sin6_addr = ip6->ip6_dst;
249 * Redo route lookup with new destination address
251 if (ip6_findroute(&nh, &dst, m) != 0) {
261 ip6->ip6_hlim -= IPV6_HLIMDEC;
264 m_clrprotoflags(m); /* Avoid confusing lower layers. */
265 IP_PROBE(send, NULL, NULL, ip6, nh.nh_ifp, NULL, ip6);
268 * XXX: we need to use destination address with embedded scope
269 * zone id, because LLTABLE uses such form of addresses for lookup.
271 dst.sin6_addr = nh.nh_addr;
272 if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6_addr))
273 dst.sin6_addr.s6_addr16[1] = htons(nh.nh_ifp->if_index & 0xffff);
275 error = (*nh.nh_ifp->if_output)(nh.nh_ifp, m,
276 (struct sockaddr *)&dst, NULL);
278 in6_ifstat_inc(nh.nh_ifp, ifs6_out_discard);
279 IP6STAT_INC(ip6s_cantforward);
281 in6_ifstat_inc(nh.nh_ifp, ifs6_out_forward);
282 IP6STAT_INC(ip6s_forward);
286 in6_ifstat_inc(rcvif, ifs6_in_discard);
289 in6_ifstat_inc(nh.nh_ifp, ifs6_out_discard);