FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_gif.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: releng/12.0/sys/netinet/in_gif.c 336676 2018-07-24 16:35:52Z andrew $");
37
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/jail.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/mbuf.h>
47 #include <sys/errno.h>
48 #include <sys/kernel.h>
49 #include <sys/sysctl.h>
50 #include <sys/malloc.h>
51 #include <sys/proc.h>
52
53 #include <net/ethernet.h>
54 #include <net/if.h>
55 #include <net/if_var.h>
56 #include <net/route.h>
57 #include <net/vnet.h>
58
59 #include <netinet/in.h>
60 #include <netinet/in_systm.h>
61 #include <netinet/ip.h>
62 #include <netinet/ip_var.h>
63 #include <netinet/in_var.h>
64 #include <netinet/ip_encap.h>
65 #include <netinet/ip_ecn.h>
66 #include <netinet/in_fib.h>
67
68 #ifdef INET6
69 #include <netinet/ip6.h>
70 #endif
71
72 #include <net/if_gif.h>
73
74 #define GIF_TTL 30
75 VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL;
76 #define V_ip_gif_ttl VNET(ip_gif_ttl)
77 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW,
78 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets");
79
80 /*
81 * We keep interfaces in a hash table using src+dst as key.
82 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
83 */
84 VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL;
85 VNET_DEFINE_STATIC(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER();
86 #define V_ipv4_hashtbl VNET(ipv4_hashtbl)
87 #define V_ipv4_list VNET(ipv4_list)
88
89 #define GIF_HASH(src, dst) (V_ipv4_hashtbl[\
90 in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
91 #define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\
92 (sc)->gif_iphdr->ip_dst.s_addr)
93 static uint32_t
94 in_gif_hashval(in_addr_t src, in_addr_t dst)
95 {
96 uint32_t ret;
97
98 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
99 return (fnv_32_buf(&dst, sizeof(dst), ret));
100 }
101
102 static int
103 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst)
104 {
105 struct gif_softc *tmp;
106
107 if (sc->gif_family == AF_INET &&
108 sc->gif_iphdr->ip_src.s_addr == src &&
109 sc->gif_iphdr->ip_dst.s_addr == dst)
110 return (EEXIST);
111
112 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
113 if (tmp == sc)
114 continue;
115 if (tmp->gif_iphdr->ip_src.s_addr == src &&
116 tmp->gif_iphdr->ip_dst.s_addr == dst)
117 return (EADDRNOTAVAIL);
118 }
119 return (0);
120 }
121
122 static void
123 in_gif_attach(struct gif_softc *sc)
124 {
125
126 if (sc->gif_options & GIF_IGNORE_SOURCE)
127 CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain);
128 else
129 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
130 }
131
132 int
133 in_gif_setopts(struct gif_softc *sc, u_int options)
134 {
135
136 /* NOTE: we are protected with gif_ioctl_sx lock */
137 MPASS(sc->gif_family == AF_INET);
138 MPASS(sc->gif_options != options);
139
140 if ((options & GIF_IGNORE_SOURCE) !=
141 (sc->gif_options & GIF_IGNORE_SOURCE)) {
142 CK_LIST_REMOVE(sc, chain);
143 sc->gif_options = options;
144 in_gif_attach(sc);
145 }
146 return (0);
147 }
148
149 int
150 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
151 {
152 struct ifreq *ifr = (struct ifreq *)data;
153 struct sockaddr_in *dst, *src;
154 struct ip *ip;
155 int error;
156
157 /* NOTE: we are protected with gif_ioctl_sx lock */
158 error = EINVAL;
159 switch (cmd) {
160 case SIOCSIFPHYADDR:
161 src = &((struct in_aliasreq *)data)->ifra_addr;
162 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
163
164 /* sanity checks */
165 if (src->sin_family != dst->sin_family ||
166 src->sin_family != AF_INET ||
167 src->sin_len != dst->sin_len ||
168 src->sin_len != sizeof(*src))
169 break;
170 if (src->sin_addr.s_addr == INADDR_ANY ||
171 dst->sin_addr.s_addr == INADDR_ANY) {
172 error = EADDRNOTAVAIL;
173 break;
174 }
175 if (V_ipv4_hashtbl == NULL)
176 V_ipv4_hashtbl = gif_hashinit();
177 error = in_gif_checkdup(sc, src->sin_addr.s_addr,
178 dst->sin_addr.s_addr);
179 if (error == EADDRNOTAVAIL)
180 break;
181 if (error == EEXIST) {
182 /* Addresses are the same. Just return. */
183 error = 0;
184 break;
185 }
186 ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO);
187 ip->ip_src.s_addr = src->sin_addr.s_addr;
188 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
189 if (sc->gif_family != 0) {
190 /* Detach existing tunnel first */
191 CK_LIST_REMOVE(sc, chain);
192 GIF_WAIT();
193 free(sc->gif_hdr, M_GIF);
194 /* XXX: should we notify about link state change? */
195 }
196 sc->gif_family = AF_INET;
197 sc->gif_iphdr = ip;
198 in_gif_attach(sc);
199 break;
200 case SIOCGIFPSRCADDR:
201 case SIOCGIFPDSTADDR:
202 if (sc->gif_family != AF_INET) {
203 error = EADDRNOTAVAIL;
204 break;
205 }
206 src = (struct sockaddr_in *)&ifr->ifr_addr;
207 memset(src, 0, sizeof(*src));
208 src->sin_family = AF_INET;
209 src->sin_len = sizeof(*src);
210 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
211 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst;
212 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
213 if (error != 0)
214 memset(src, 0, sizeof(*src));
215 break;
216 }
217 return (error);
218 }
219
220 int
221 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
222 {
223 struct gif_softc *sc = ifp->if_softc;
224 struct ip *ip;
225 int len;
226
227 /* prepend new IP header */
228 MPASS(in_epoch(net_epoch_preempt));
229 len = sizeof(struct ip);
230 #ifndef __NO_STRICT_ALIGNMENT
231 if (proto == IPPROTO_ETHERIP)
232 len += ETHERIP_ALIGN;
233 #endif
234 M_PREPEND(m, len, M_NOWAIT);
235 if (m == NULL)
236 return (ENOBUFS);
237 #ifndef __NO_STRICT_ALIGNMENT
238 if (proto == IPPROTO_ETHERIP) {
239 len = mtod(m, vm_offset_t) & 3;
240 KASSERT(len == 0 || len == ETHERIP_ALIGN,
241 ("in_gif_output: unexpected misalignment"));
242 m->m_data += len;
243 m->m_len -= ETHERIP_ALIGN;
244 }
245 #endif
246 ip = mtod(m, struct ip *);
247
248 MPASS(sc->gif_family == AF_INET);
249 bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
250 ip->ip_p = proto;
251 /* version will be set in ip_output() */
252 ip->ip_ttl = V_ip_gif_ttl;
253 ip->ip_len = htons(m->m_pkthdr.len);
254 ip->ip_tos = ecn;
255
256 return (ip_output(m, NULL, NULL, 0, NULL, NULL));
257 }
258
259 static int
260 in_gif_input(struct mbuf *m, int off, int proto, void *arg)
261 {
262 struct gif_softc *sc = arg;
263 struct ifnet *gifp;
264 struct ip *ip;
265 uint8_t ecn;
266
267 MPASS(in_epoch(net_epoch_preempt));
268 if (sc == NULL) {
269 m_freem(m);
270 KMOD_IPSTAT_INC(ips_nogif);
271 return (IPPROTO_DONE);
272 }
273 gifp = GIF2IFP(sc);
274 if ((gifp->if_flags & IFF_UP) != 0) {
275 ip = mtod(m, struct ip *);
276 ecn = ip->ip_tos;
277 m_adj(m, off);
278 gif_input(m, gifp, proto, ecn);
279 } else {
280 m_freem(m);
281 KMOD_IPSTAT_INC(ips_nogif);
282 }
283 return (IPPROTO_DONE);
284 }
285
286 static int
287 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
288 {
289 const struct ip *ip;
290 struct gif_softc *sc;
291 int ret;
292
293 if (V_ipv4_hashtbl == NULL)
294 return (0);
295
296 MPASS(in_epoch(net_epoch_preempt));
297 ip = mtod(m, const struct ip *);
298 /*
299 * NOTE: it is safe to iterate without any locking here, because softc
300 * can be reclaimed only when we are not within net_epoch_preempt
301 * section, but ip_encap lookup+input are executed in epoch section.
302 */
303 ret = 0;
304 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr,
305 ip->ip_src.s_addr), chain) {
306 /*
307 * This is an inbound packet, its ip_dst is source address
308 * in softc.
309 */
310 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr &&
311 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) {
312 ret = ENCAP_DRV_LOOKUP;
313 goto done;
314 }
315 }
316 /*
317 * No exact match.
318 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
319 */
320 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) {
321 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) {
322 ret = 32 + 8; /* src + proto */
323 goto done;
324 }
325 }
326 return (0);
327 done:
328 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
329 return (0);
330 /* ingress filters on outer source */
331 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
332 struct nhop4_basic nh4;
333 struct in_addr dst;
334
335 dst = ip->ip_src;
336 if (fib4_lookup_nh_basic(sc->gif_fibnum, dst, 0, 0, &nh4) != 0)
337 return (0);
338 if (nh4.nh_ifp != m->m_pkthdr.rcvif)
339 return (0);
340 }
341 *arg = sc;
342 return (ret);
343 }
344
345 static struct {
346 const struct encap_config encap;
347 const struct encaptab *cookie;
348 } ipv4_encap_cfg[] = {
349 {
350 .encap = {
351 .proto = IPPROTO_IPV4,
352 .min_length = 2 * sizeof(struct ip),
353 .exact_match = ENCAP_DRV_LOOKUP,
354 .lookup = in_gif_lookup,
355 .input = in_gif_input
356 },
357 },
358 #ifdef INET6
359 {
360 .encap = {
361 .proto = IPPROTO_IPV6,
362 .min_length = sizeof(struct ip) +
363 sizeof(struct ip6_hdr),
364 .exact_match = ENCAP_DRV_LOOKUP,
365 .lookup = in_gif_lookup,
366 .input = in_gif_input
367 },
368 },
369 #endif
370 {
371 .encap = {
372 .proto = IPPROTO_ETHERIP,
373 .min_length = sizeof(struct ip) +
374 sizeof(struct etherip_header) +
375 sizeof(struct ether_header),
376 .exact_match = ENCAP_DRV_LOOKUP,
377 .lookup = in_gif_lookup,
378 .input = in_gif_input
379 },
380 }
381 };
382
383 void
384 in_gif_init(void)
385 {
386 int i;
387
388 if (!IS_DEFAULT_VNET(curvnet))
389 return;
390 for (i = 0; i < nitems(ipv4_encap_cfg); i++)
391 ipv4_encap_cfg[i].cookie = ip_encap_attach(
392 &ipv4_encap_cfg[i].encap, NULL, M_WAITOK);
393 }
394
395 void
396 in_gif_uninit(void)
397 {
398 int i;
399
400 if (IS_DEFAULT_VNET(curvnet)) {
401 for (i = 0; i < nitems(ipv4_encap_cfg); i++)
402 ip_encap_detach(ipv4_encap_cfg[i].cookie);
403 }
404 if (V_ipv4_hashtbl != NULL)
405 gif_hashdestroy(V_ipv4_hashtbl);
406 }
407
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