xref: /freebsd/sys/netinet/in_gif.c (revision b941bc1d6eddacf06eb515faa5d894f2ee2a9011)
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("$FreeBSD$");
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 
52 #include <net/ethernet.h>
53 #include <net/if.h>
54 #include <net/if_var.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 static VNET_DEFINE(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 static VNET_DEFINE(struct gif_list *, ipv4_hashtbl) = NULL;
84 static VNET_DEFINE(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER();
85 #define	V_ipv4_hashtbl		VNET(ipv4_hashtbl)
86 #define	V_ipv4_list		VNET(ipv4_list)
87 
88 #define	GIF_HASH(src, dst)	(V_ipv4_hashtbl[\
89     in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
90 #define	GIF_HASH_SC(sc)		GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\
91     (sc)->gif_iphdr->ip_dst.s_addr)
92 static uint32_t
93 in_gif_hashval(in_addr_t src, in_addr_t dst)
94 {
95 	uint32_t ret;
96 
97 	ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
98 	return (fnv_32_buf(&dst, sizeof(dst), ret));
99 }
100 
101 static int
102 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst)
103 {
104 	struct gif_softc *tmp;
105 
106 	if (sc->gif_family == AF_INET &&
107 	    sc->gif_iphdr->ip_src.s_addr == src &&
108 	    sc->gif_iphdr->ip_dst.s_addr == dst)
109 		return (EEXIST);
110 
111 	CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
112 		if (tmp == sc)
113 			continue;
114 		if (tmp->gif_iphdr->ip_src.s_addr == src &&
115 		    tmp->gif_iphdr->ip_dst.s_addr == dst)
116 			return (EADDRNOTAVAIL);
117 	}
118 	return (0);
119 }
120 
121 static void
122 in_gif_attach(struct gif_softc *sc)
123 {
124 
125 	if (sc->gif_options & GIF_IGNORE_SOURCE)
126 		CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain);
127 	else
128 		CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
129 }
130 
131 int
132 in_gif_setopts(struct gif_softc *sc, u_int options)
133 {
134 
135 	/* NOTE: we are protected with gif_ioctl_sx lock */
136 	MPASS(sc->gif_family == AF_INET);
137 	MPASS(sc->gif_options != options);
138 
139 	if ((options & GIF_IGNORE_SOURCE) !=
140 	    (sc->gif_options & GIF_IGNORE_SOURCE)) {
141 		CK_LIST_REMOVE(sc, chain);
142 		sc->gif_options = options;
143 		in_gif_attach(sc);
144 	}
145 	return (0);
146 }
147 
148 int
149 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
150 {
151 	struct ifreq *ifr = (struct ifreq *)data;
152 	struct sockaddr_in *dst, *src;
153 	struct ip *ip;
154 	int error;
155 
156 	/* NOTE: we are protected with gif_ioctl_sx lock */
157 	error = EINVAL;
158 	switch (cmd) {
159 	case SIOCSIFPHYADDR:
160 		src = &((struct in_aliasreq *)data)->ifra_addr;
161 		dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
162 
163 		/* sanity checks */
164 		if (src->sin_family != dst->sin_family ||
165 		    src->sin_family != AF_INET ||
166 		    src->sin_len != dst->sin_len ||
167 		    src->sin_len != sizeof(*src))
168 			break;
169 		if (src->sin_addr.s_addr == INADDR_ANY ||
170 		    dst->sin_addr.s_addr == INADDR_ANY) {
171 			error = EADDRNOTAVAIL;
172 			break;
173 		}
174 		if (V_ipv4_hashtbl == NULL)
175 			V_ipv4_hashtbl = gif_hashinit();
176 		error = in_gif_checkdup(sc, src->sin_addr.s_addr,
177 		    dst->sin_addr.s_addr);
178 		if (error == EADDRNOTAVAIL)
179 			break;
180 		if (error == EEXIST) {
181 			/* Addresses are the same. Just return. */
182 			error = 0;
183 			break;
184 		}
185 		ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO);
186 		ip->ip_src.s_addr = src->sin_addr.s_addr;
187 		ip->ip_dst.s_addr = dst->sin_addr.s_addr;
188 		if (sc->gif_family != 0) {
189 			/* Detach existing tunnel first */
190 			CK_LIST_REMOVE(sc, chain);
191 			GIF_WAIT();
192 			free(sc->gif_hdr, M_GIF);
193 			/* XXX: should we notify about link state change? */
194 		}
195 		sc->gif_family = AF_INET;
196 		sc->gif_iphdr = ip;
197 		in_gif_attach(sc);
198 		break;
199 	case SIOCGIFPSRCADDR:
200 	case SIOCGIFPDSTADDR:
201 		if (sc->gif_family != AF_INET) {
202 			error = EADDRNOTAVAIL;
203 			break;
204 		}
205 		src = (struct sockaddr_in *)&ifr->ifr_addr;
206 		memset(src, 0, sizeof(*src));
207 		src->sin_family = AF_INET;
208 		src->sin_len = sizeof(*src);
209 		src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
210 		    sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst;
211 		error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
212 		if (error != 0)
213 			memset(src, 0, sizeof(*src));
214 		break;
215 	}
216 	return (error);
217 }
218 
219 int
220 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
221 {
222 	struct gif_softc *sc = ifp->if_softc;
223 	struct ip *ip;
224 	int len;
225 
226 	/* prepend new IP header */
227 	MPASS(in_epoch());
228 	len = sizeof(struct ip);
229 #ifndef __NO_STRICT_ALIGNMENT
230 	if (proto == IPPROTO_ETHERIP)
231 		len += ETHERIP_ALIGN;
232 #endif
233 	M_PREPEND(m, len, M_NOWAIT);
234 	if (m == NULL)
235 		return (ENOBUFS);
236 #ifndef __NO_STRICT_ALIGNMENT
237 	if (proto == IPPROTO_ETHERIP) {
238 		len = mtod(m, vm_offset_t) & 3;
239 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
240 		    ("in_gif_output: unexpected misalignment"));
241 		m->m_data += len;
242 		m->m_len -= ETHERIP_ALIGN;
243 	}
244 #endif
245 	ip = mtod(m, struct ip *);
246 
247 	MPASS(sc->gif_family == AF_INET);
248 	bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
249 	ip->ip_p = proto;
250 	/* version will be set in ip_output() */
251 	ip->ip_ttl = V_ip_gif_ttl;
252 	ip->ip_len = htons(m->m_pkthdr.len);
253 	ip->ip_tos = ecn;
254 
255 	return (ip_output(m, NULL, NULL, 0, NULL, NULL));
256 }
257 
258 static int
259 in_gif_input(struct mbuf *m, int off, int proto, void *arg)
260 {
261 	struct gif_softc *sc = arg;
262 	struct ifnet *gifp;
263 	struct ip *ip;
264 	uint8_t ecn;
265 
266 	MPASS(in_epoch());
267 	if (sc == NULL) {
268 		m_freem(m);
269 		KMOD_IPSTAT_INC(ips_nogif);
270 		return (IPPROTO_DONE);
271 	}
272 	gifp = GIF2IFP(sc);
273 	if ((gifp->if_flags & IFF_UP) != 0) {
274 		ip = mtod(m, struct ip *);
275 		ecn = ip->ip_tos;
276 		m_adj(m, off);
277 		gif_input(m, gifp, proto, ecn);
278 	} else {
279 		m_freem(m);
280 		KMOD_IPSTAT_INC(ips_nogif);
281 	}
282 	return (IPPROTO_DONE);
283 }
284 
285 static int
286 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
287 {
288 	const struct ip *ip;
289 	struct gif_softc *sc;
290 	int ret;
291 
292 	MPASS(in_epoch());
293 	ip = mtod(m, const struct ip *);
294 	/*
295 	 * NOTE: it is safe to iterate without any locking here, because softc
296 	 * can be reclaimed only when we are not within net_epoch_preempt
297 	 * section, but ip_encap lookup+input are executed in epoch section.
298 	 */
299 	ret = 0;
300 	CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr,
301 	    ip->ip_src.s_addr), chain) {
302 		/*
303 		 * This is an inbound packet, its ip_dst is source address
304 		 * in softc.
305 		 */
306 		if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr &&
307 		    sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) {
308 			ret = ENCAP_DRV_LOOKUP;
309 			goto done;
310 		}
311 	}
312 	/*
313 	 * No exact match.
314 	 * Check the list of interfaces with GIF_IGNORE_SOURCE flag.
315 	 */
316 	CK_LIST_FOREACH(sc, &V_ipv4_list, chain) {
317 		if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) {
318 			ret = 32 + 8; /* src + proto */
319 			goto done;
320 		}
321 	}
322 	return (0);
323 done:
324 	if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
325 		return (0);
326 	/* ingress filters on outer source */
327 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
328 		struct nhop4_basic nh4;
329 		struct in_addr dst;
330 
331 		dst = ip->ip_src;
332 		if (fib4_lookup_nh_basic(sc->gif_fibnum, dst, 0, 0, &nh4) != 0)
333 			return (0);
334 		if (nh4.nh_ifp != m->m_pkthdr.rcvif)
335 			return (0);
336 	}
337 	*arg = sc;
338 	return (ret);
339 }
340 
341 static struct {
342 	const struct encap_config encap;
343 	const struct encaptab *cookie;
344 } ipv4_encap_cfg[] = {
345 	{
346 		.encap = {
347 			.proto = IPPROTO_IPV4,
348 			.min_length = 2 * sizeof(struct ip),
349 			.exact_match = ENCAP_DRV_LOOKUP,
350 			.lookup = in_gif_lookup,
351 			.input = in_gif_input
352 		},
353 	},
354 #ifdef INET6
355 	{
356 		.encap = {
357 			.proto = IPPROTO_IPV6,
358 			.min_length = sizeof(struct ip) +
359 			    sizeof(struct ip6_hdr),
360 			.exact_match = ENCAP_DRV_LOOKUP,
361 			.lookup = in_gif_lookup,
362 			.input = in_gif_input
363 		},
364 	},
365 #endif
366 	{
367 		.encap = {
368 			.proto = IPPROTO_ETHERIP,
369 			.min_length = sizeof(struct ip) +
370 			    sizeof(struct etherip_header) +
371 			    sizeof(struct ether_header),
372 			.exact_match = ENCAP_DRV_LOOKUP,
373 			.lookup = in_gif_lookup,
374 			.input = in_gif_input
375 		},
376 	}
377 };
378 
379 void
380 in_gif_init(void)
381 {
382 	int i;
383 
384 	if (!IS_DEFAULT_VNET(curvnet))
385 		return;
386 	for (i = 0; i < nitems(ipv4_encap_cfg); i++)
387 		ipv4_encap_cfg[i].cookie = ip_encap_attach(
388 		    &ipv4_encap_cfg[i].encap, NULL, M_WAITOK);
389 }
390 
391 void
392 in_gif_uninit(void)
393 {
394 	int i;
395 
396 	if (IS_DEFAULT_VNET(curvnet)) {
397 		for (i = 0; i < nitems(ipv4_encap_cfg); i++)
398 			ip_encap_detach(ipv4_encap_cfg[i].cookie);
399 	}
400 	if (V_ipv4_hashtbl != NULL)
401 		gif_hashdestroy(V_ipv4_hashtbl);
402 }
403 
404