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 #include "opt_inet.h"
37 #include "opt_inet6.h"
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/jail.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/mbuf.h>
45 #include <sys/errno.h>
46 #include <sys/kernel.h>
47 #include <sys/sysctl.h>
48 #include <sys/malloc.h>
49 #include <sys/proc.h>
50
51 #include <net/ethernet.h>
52 #include <net/if.h>
53 #include <net/if_var.h>
54 #include <net/if_private.h>
55 #include <net/route.h>
56 #include <net/vnet.h>
57
58 #include <netinet/in.h>
59 #include <netinet/in_systm.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/in_var.h>
63 #include <netinet/ip_encap.h>
64 #include <netinet/ip_ecn.h>
65 #include <netinet/in_fib.h>
66
67 #ifdef INET6
68 #include <netinet/ip6.h>
69 #endif
70
71 #include <net/if_gif.h>
72
73 #define GIF_TTL 30
74 VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL;
75 #define V_ip_gif_ttl VNET(ip_gif_ttl)
76 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW,
77 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets");
78
79 /*
80 * We keep interfaces in a hash table using src+dst as key.
81 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
82 */
83 VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL;
84 VNET_DEFINE_STATIC(struct gif_list *, ipv4_srchashtbl) = 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_srchashtbl VNET(ipv4_srchashtbl)
88 #define V_ipv4_list VNET(ipv4_list)
89
90 #define GIF_HASH(src, dst) (V_ipv4_hashtbl[\
91 in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
92 #define GIF_SRCHASH(src) (V_ipv4_srchashtbl[\
93 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)])
94 #define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\
95 (sc)->gif_iphdr->ip_dst.s_addr)
96 static uint32_t
in_gif_hashval(in_addr_t src,in_addr_t dst)97 in_gif_hashval(in_addr_t src, in_addr_t dst)
98 {
99 uint32_t ret;
100
101 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
102 return (fnv_32_buf(&dst, sizeof(dst), ret));
103 }
104
105 static int
in_gif_checkdup(const struct gif_softc * sc,in_addr_t src,in_addr_t dst)106 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst)
107 {
108 struct gif_softc *tmp;
109
110 if (sc->gif_family == AF_INET &&
111 sc->gif_iphdr->ip_src.s_addr == src &&
112 sc->gif_iphdr->ip_dst.s_addr == dst)
113 return (EEXIST);
114
115 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
116 if (tmp == sc)
117 continue;
118 if (tmp->gif_iphdr->ip_src.s_addr == src &&
119 tmp->gif_iphdr->ip_dst.s_addr == dst)
120 return (EADDRNOTAVAIL);
121 }
122 return (0);
123 }
124
125 /*
126 * Check that ingress address belongs to local host.
127 */
128 static void
in_gif_set_running(struct gif_softc * sc)129 in_gif_set_running(struct gif_softc *sc)
130 {
131
132 if (in_localip(sc->gif_iphdr->ip_src))
133 GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
134 else
135 GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
136 }
137
138 /*
139 * ifaddr_event handler.
140 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
141 * source address spoofing.
142 */
143 static void
in_gif_srcaddr(void * arg __unused,const struct sockaddr * sa,int event __unused)144 in_gif_srcaddr(void *arg __unused, const struct sockaddr *sa,
145 int event __unused)
146 {
147 const struct sockaddr_in *sin;
148 struct gif_softc *sc;
149
150 /* Check that VNET is ready */
151 if (V_ipv4_hashtbl == NULL)
152 return;
153
154 NET_EPOCH_ASSERT();
155 sin = (const struct sockaddr_in *)sa;
156 CK_LIST_FOREACH(sc, &GIF_SRCHASH(sin->sin_addr.s_addr), srchash) {
157 if (sc->gif_iphdr->ip_src.s_addr != sin->sin_addr.s_addr)
158 continue;
159 in_gif_set_running(sc);
160 }
161 }
162
163 static void
in_gif_attach(struct gif_softc * sc)164 in_gif_attach(struct gif_softc *sc)
165 {
166
167 if (sc->gif_options & GIF_IGNORE_SOURCE)
168 CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain);
169 else
170 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
171
172 CK_LIST_INSERT_HEAD(&GIF_SRCHASH(sc->gif_iphdr->ip_src.s_addr),
173 sc, srchash);
174 }
175
176 int
in_gif_setopts(struct gif_softc * sc,u_int options)177 in_gif_setopts(struct gif_softc *sc, u_int options)
178 {
179
180 /* NOTE: we are protected with gif_ioctl_sx lock */
181 MPASS(sc->gif_family == AF_INET);
182 MPASS(sc->gif_options != options);
183
184 if ((options & GIF_IGNORE_SOURCE) !=
185 (sc->gif_options & GIF_IGNORE_SOURCE)) {
186 CK_LIST_REMOVE(sc, srchash);
187 CK_LIST_REMOVE(sc, chain);
188 sc->gif_options = options;
189 in_gif_attach(sc);
190 }
191 return (0);
192 }
193
194 int
in_gif_ioctl(struct gif_softc * sc,u_long cmd,caddr_t data)195 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
196 {
197 struct ifreq *ifr = (struct ifreq *)data;
198 struct epoch_tracker et;
199 struct sockaddr_in *dst, *src;
200 struct ip *ip;
201 int error;
202
203 /* NOTE: we are protected with gif_ioctl_sx lock */
204 error = EINVAL;
205 switch (cmd) {
206 case SIOCSIFPHYADDR:
207 src = &((struct in_aliasreq *)data)->ifra_addr;
208 dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
209
210 /* sanity checks */
211 if (src->sin_family != dst->sin_family ||
212 src->sin_family != AF_INET ||
213 src->sin_len != dst->sin_len ||
214 src->sin_len != sizeof(*src))
215 break;
216 if (src->sin_addr.s_addr == INADDR_ANY ||
217 dst->sin_addr.s_addr == INADDR_ANY) {
218 error = EADDRNOTAVAIL;
219 break;
220 }
221 if (V_ipv4_hashtbl == NULL) {
222 V_ipv4_hashtbl = gif_hashinit();
223 V_ipv4_srchashtbl = gif_hashinit();
224 }
225 error = in_gif_checkdup(sc, src->sin_addr.s_addr,
226 dst->sin_addr.s_addr);
227 if (error == EADDRNOTAVAIL)
228 break;
229 if (error == EEXIST) {
230 /* Addresses are the same. Just return. */
231 error = 0;
232 break;
233 }
234 ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO);
235 ip->ip_src.s_addr = src->sin_addr.s_addr;
236 ip->ip_dst.s_addr = dst->sin_addr.s_addr;
237 if (sc->gif_family != 0) {
238 /* Detach existing tunnel first */
239 CK_LIST_REMOVE(sc, srchash);
240 CK_LIST_REMOVE(sc, chain);
241 GIF_WAIT();
242 free(sc->gif_hdr, M_GIF);
243 /* XXX: should we notify about link state change? */
244 }
245 sc->gif_family = AF_INET;
246 sc->gif_iphdr = ip;
247 in_gif_attach(sc);
248 NET_EPOCH_ENTER(et);
249 in_gif_set_running(sc);
250 NET_EPOCH_EXIT(et);
251 break;
252 case SIOCGIFPSRCADDR:
253 case SIOCGIFPDSTADDR:
254 if (sc->gif_family != AF_INET) {
255 error = EADDRNOTAVAIL;
256 break;
257 }
258 src = (struct sockaddr_in *)&ifr->ifr_addr;
259 memset(src, 0, sizeof(*src));
260 src->sin_family = AF_INET;
261 src->sin_len = sizeof(*src);
262 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
263 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst;
264 error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
265 if (error != 0)
266 memset(src, 0, sizeof(*src));
267 break;
268 }
269 return (error);
270 }
271
272 int
in_gif_output(struct ifnet * ifp,struct mbuf * m,int proto,uint8_t ecn)273 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
274 {
275 struct gif_softc *sc = ifp->if_softc;
276 struct ip *ip;
277
278 /* prepend new IP header */
279 NET_EPOCH_ASSERT();
280 M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
281 if (m == NULL)
282 return (ENOBUFS);
283 ip = mtod(m, struct ip *);
284
285 MPASS(sc->gif_family == AF_INET);
286 memcpy(ip, sc->gif_iphdr, sizeof(struct ip));
287 ip->ip_p = proto;
288 /* version will be set in ip_output() */
289 ip->ip_ttl = V_ip_gif_ttl;
290 ip->ip_len = htons(m->m_pkthdr.len);
291 ip->ip_tos = ecn;
292
293 return (ip_output(m, NULL, NULL, 0, NULL, NULL));
294 }
295
296 static int
in_gif_input(struct mbuf * m,int off,int proto,void * arg)297 in_gif_input(struct mbuf *m, int off, int proto, void *arg)
298 {
299 struct gif_softc *sc = arg;
300 struct ifnet *gifp;
301 struct ip *ip;
302 uint8_t ecn;
303
304 NET_EPOCH_ASSERT();
305 if (sc == NULL) {
306 m_freem(m);
307 KMOD_IPSTAT_INC(ips_nogif);
308 return (IPPROTO_DONE);
309 }
310 gifp = GIF2IFP(sc);
311 if ((gifp->if_flags & IFF_UP) != 0) {
312 ip = mtod(m, struct ip *);
313 ecn = ip->ip_tos;
314 m_adj(m, off);
315 gif_input(m, gifp, proto, ecn);
316 } else {
317 m_freem(m);
318 KMOD_IPSTAT_INC(ips_nogif);
319 }
320 return (IPPROTO_DONE);
321 }
322
323 static int
in_gif_lookup(const struct mbuf * m,int off,int proto,void ** arg)324 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
325 {
326 const struct ip *ip;
327 struct gif_softc *sc;
328 int ret;
329
330 if (V_ipv4_hashtbl == NULL)
331 return (0);
332
333 NET_EPOCH_ASSERT();
334 ip = mtod(m, const struct ip *);
335 /*
336 * NOTE: it is safe to iterate without any locking here, because softc
337 * can be reclaimed only when we are not within net_epoch_preempt
338 * section, but ip_encap lookup+input are executed in epoch section.
339 */
340 ret = 0;
341 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr,
342 ip->ip_src.s_addr), chain) {
343 /*
344 * This is an inbound packet, its ip_dst is source address
345 * in softc.
346 */
347 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr &&
348 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) {
349 ret = ENCAP_DRV_LOOKUP;
350 goto done;
351 }
352 }
353 /*
354 * No exact match.
355 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
356 */
357 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) {
358 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) {
359 ret = 32 + 8; /* src + proto */
360 goto done;
361 }
362 }
363 return (0);
364 done:
365 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
366 return (0);
367 /* ingress filters on outer source */
368 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
369 if (fib4_check_urpf(sc->gif_fibnum, ip->ip_src, 0, NHR_NONE,
370 m->m_pkthdr.rcvif) == 0)
371 return (0);
372 }
373 *arg = sc;
374 return (ret);
375 }
376
377 static const struct srcaddrtab *ipv4_srcaddrtab;
378 static struct {
379 const struct encap_config encap;
380 const struct encaptab *cookie;
381 } ipv4_encap_cfg[] = {
382 {
383 .encap = {
384 .proto = IPPROTO_IPV4,
385 .min_length = 2 * sizeof(struct ip),
386 .exact_match = ENCAP_DRV_LOOKUP,
387 .lookup = in_gif_lookup,
388 .input = in_gif_input
389 },
390 },
391 #ifdef INET6
392 {
393 .encap = {
394 .proto = IPPROTO_IPV6,
395 .min_length = sizeof(struct ip) +
396 sizeof(struct ip6_hdr),
397 .exact_match = ENCAP_DRV_LOOKUP,
398 .lookup = in_gif_lookup,
399 .input = in_gif_input
400 },
401 },
402 #endif
403 {
404 .encap = {
405 .proto = IPPROTO_ETHERIP,
406 .min_length = sizeof(struct ip) +
407 sizeof(struct etherip_header) +
408 sizeof(struct ether_header),
409 .exact_match = ENCAP_DRV_LOOKUP,
410 .lookup = in_gif_lookup,
411 .input = in_gif_input
412 },
413 }
414 };
415
416 void
in_gif_init(void)417 in_gif_init(void)
418 {
419 int i;
420
421 if (!IS_DEFAULT_VNET(curvnet))
422 return;
423
424 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gif_srcaddr,
425 NULL, M_WAITOK);
426 for (i = 0; i < nitems(ipv4_encap_cfg); i++)
427 ipv4_encap_cfg[i].cookie = ip_encap_attach(
428 &ipv4_encap_cfg[i].encap, NULL, M_WAITOK);
429 }
430
431 void
in_gif_uninit(void)432 in_gif_uninit(void)
433 {
434 int i;
435
436 if (IS_DEFAULT_VNET(curvnet)) {
437 for (i = 0; i < nitems(ipv4_encap_cfg); i++)
438 ip_encap_detach(ipv4_encap_cfg[i].cookie);
439 ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
440 }
441 if (V_ipv4_hashtbl != NULL) {
442 gif_hashdestroy(V_ipv4_hashtbl);
443 V_ipv4_hashtbl = NULL;
444 GIF_WAIT();
445 gif_hashdestroy(V_ipv4_srchashtbl);
446 }
447 }
448