1 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
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32 * My grandfather said that there's a devil inside tunnelling technology...
34 * We have surprisingly many protocols that want packets with IP protocol
35 * #4 or #41. Here's a list of protocols that want protocol #41:
36 * RFC1933 configured tunnel
37 * RFC1933 automatic tunnel
38 * RFC2401 IPsec tunnel
39 * RFC2473 IPv6 generic packet tunnelling
40 * RFC2529 6over4 tunnel
41 * mobile-ip6 (uses RFC2473)
44 * Here's a list of protocol that want protocol #4:
45 * RFC1853 IPv4-in-IPv4 tunnelling
46 * RFC2003 IPv4 encapsulation within IPv4
47 * RFC2344 reverse tunnelling for mobile-ip4
48 * RFC2401 IPsec tunnel
49 * Well, what can I say. They impose different en/decapsulation mechanism
50 * from each other, so they need separate protocol handler. The only one
51 * we can easily determine by protocol # is IPsec, which always has
52 * AH/ESP/IPComp header right after outer IP header.
54 * So, clearly good old protosw does not work for protocol #4 and #41.
55 * The code will let you match protocol via src/dst address pair.
57 /* XXX is M_NETADDR correct? */
59 #include <sys/cdefs.h>
60 __FBSDID("$FreeBSD$");
62 #include "opt_mrouting.h"
64 #include "opt_inet6.h"
66 #include <sys/param.h>
67 #include <sys/systm.h>
69 #include <sys/mutex.h>
70 #include <sys/socket.h>
71 #include <sys/sockio.h>
73 #include <sys/errno.h>
74 #include <sys/protosw.h>
75 #include <sys/queue.h>
78 #include <net/route.h>
80 #include <netinet/in.h>
81 #include <netinet/in_systm.h>
82 #include <netinet/ip.h>
83 #include <netinet/ip_var.h>
84 #include <netinet/ip_encap.h>
87 #include <netinet/ip6.h>
88 #include <netinet6/ip6_var.h>
91 #include <machine/stdarg.h>
93 #include <sys/kernel.h>
94 #include <sys/malloc.h>
95 static MALLOC_DEFINE(M_NETADDR, "encap_export_host", "Export host address structure");
97 static void encap_add(struct encaptab *);
98 static int mask_match(const struct encaptab *, const struct sockaddr *,
99 const struct sockaddr *);
100 static void encap_fillarg(struct mbuf *, void *);
103 * All global variables in ip_encap.c are locked using encapmtx.
105 static struct mtx encapmtx;
106 MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
107 static LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(encaptab);
111 encap4_input(struct mbuf **mp, int *offp, int proto)
115 struct sockaddr_in s, d;
116 const struct protosw *psw;
117 struct encaptab *ep, *match;
119 int matchprio, off, prio;
123 ip = mtod(m, struct ip *);
125 bzero(&s, sizeof(s));
126 s.sin_family = AF_INET;
127 s.sin_len = sizeof(struct sockaddr_in);
128 s.sin_addr = ip->ip_src;
129 bzero(&d, sizeof(d));
130 d.sin_family = AF_INET;
131 d.sin_len = sizeof(struct sockaddr_in);
132 d.sin_addr = ip->ip_dst;
139 LIST_FOREACH(ep, &encaptab, chain) {
140 if (ep->af != AF_INET)
142 if (ep->proto >= 0 && ep->proto != proto)
145 prio = (*ep->func)(m, off, proto, ep->arg);
148 * it's inbound traffic, we need to match in reverse
151 prio = mask_match(ep, (struct sockaddr *)&d,
152 (struct sockaddr *)&s);
156 * We prioritize the matches by using bit length of the
157 * matches. mask_match() and user-supplied matching function
158 * should return the bit length of the matches (for example,
159 * if both src/dst are matched for IPv4, 64 should be returned).
160 * 0 or negative return value means "it did not match".
162 * The question is, since we have two "mask" portion, we
163 * cannot really define total order between entries.
164 * For example, which of these should be preferred?
165 * mask_match() returns 48 (32 + 16) for both of them.
166 * src=3ffe::/16, dst=3ffe:501::/32
167 * src=3ffe:501::/32, dst=3ffe::/16
169 * We need to loop through all the possible candidates
170 * to get the best match - the search takes O(n) for
171 * n attachments (i.e. interfaces).
175 if (prio > matchprio) {
184 mtx_unlock(&encapmtx);
187 /* found a match, "match" has the best one */
188 if (psw != NULL && psw->pr_input != NULL) {
189 encap_fillarg(m, arg);
190 (*psw->pr_input)(mp, offp, proto);
193 return (IPPROTO_DONE);
196 /* last resort: inject to raw socket */
197 return (rip_input(mp, offp, proto));
203 encap6_input(struct mbuf **mp, int *offp, int proto)
205 struct mbuf *m = *mp;
207 struct sockaddr_in6 s, d;
208 const struct protosw *psw;
209 struct encaptab *ep, *match;
213 ip6 = mtod(m, struct ip6_hdr *);
215 bzero(&s, sizeof(s));
216 s.sin6_family = AF_INET6;
217 s.sin6_len = sizeof(struct sockaddr_in6);
218 s.sin6_addr = ip6->ip6_src;
219 bzero(&d, sizeof(d));
220 d.sin6_family = AF_INET6;
221 d.sin6_len = sizeof(struct sockaddr_in6);
222 d.sin6_addr = ip6->ip6_dst;
229 LIST_FOREACH(ep, &encaptab, chain) {
230 if (ep->af != AF_INET6)
232 if (ep->proto >= 0 && ep->proto != proto)
235 prio = (*ep->func)(m, *offp, proto, ep->arg);
238 * it's inbound traffic, we need to match in reverse
241 prio = mask_match(ep, (struct sockaddr *)&d,
242 (struct sockaddr *)&s);
245 /* see encap4_input() for issues here */
248 if (prio > matchprio) {
257 mtx_unlock(&encapmtx);
261 if (psw != NULL && psw->pr_input != NULL) {
262 encap_fillarg(m, arg);
263 return (*psw->pr_input)(mp, offp, proto);
266 return (IPPROTO_DONE);
270 /* last resort: inject to raw socket */
271 return rip6_input(mp, offp, proto);
275 /*lint -sem(encap_add, custodial(1)) */
277 encap_add(struct encaptab *ep)
280 mtx_assert(&encapmtx, MA_OWNED);
281 LIST_INSERT_HEAD(&encaptab, ep, chain);
285 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
286 * length of mask (sm and dm) is assumed to be same as sp/dp.
287 * Return value will be necessary as input (cookie) for encap_detach().
289 const struct encaptab *
290 encap_attach(int af, int proto, const struct sockaddr *sp,
291 const struct sockaddr *sm, const struct sockaddr *dp,
292 const struct sockaddr *dm, const struct protosw *psw, void *arg)
296 /* sanity check on args */
297 if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst))
299 if (sp->sa_len != dp->sa_len)
301 if (af != sp->sa_family || af != dp->sa_family)
304 /* check if anyone have already attached with exactly same config */
306 LIST_FOREACH(ep, &encaptab, chain) {
309 if (ep->proto != proto)
311 if (ep->src.ss_len != sp->sa_len ||
312 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
313 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
315 if (ep->dst.ss_len != dp->sa_len ||
316 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
317 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
320 mtx_unlock(&encapmtx);
324 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
326 mtx_unlock(&encapmtx);
329 bzero(ep, sizeof(*ep));
333 bcopy(sp, &ep->src, sp->sa_len);
334 bcopy(sm, &ep->srcmask, sp->sa_len);
335 bcopy(dp, &ep->dst, dp->sa_len);
336 bcopy(dm, &ep->dstmask, dp->sa_len);
341 mtx_unlock(&encapmtx);
345 const struct encaptab *
346 encap_attach_func(int af, int proto,
347 int (*func)(const struct mbuf *, int, int, void *),
348 const struct protosw *psw, void *arg)
352 /* sanity check on args */
356 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
359 bzero(ep, sizeof(*ep));
369 mtx_unlock(&encapmtx);
374 encap_detach(const struct encaptab *cookie)
376 const struct encaptab *ep = cookie;
380 LIST_FOREACH(p, &encaptab, chain) {
382 LIST_REMOVE(p, chain);
383 mtx_unlock(&encapmtx);
384 free(p, M_NETADDR); /*XXX*/
388 mtx_unlock(&encapmtx);
394 mask_match(const struct encaptab *ep, const struct sockaddr *sp,
395 const struct sockaddr *dp)
397 struct sockaddr_storage s;
398 struct sockaddr_storage d;
400 const u_int8_t *p, *q;
404 if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
406 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
408 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
413 p = (const u_int8_t *)sp;
414 q = (const u_int8_t *)&ep->srcmask;
416 for (i = 0 ; i < sp->sa_len; i++) {
419 matchlen += (q[i] ? 8 : 0);
422 p = (const u_int8_t *)dp;
423 q = (const u_int8_t *)&ep->dstmask;
425 for (i = 0 ; i < dp->sa_len; i++) {
427 /* XXX rough estimate */
428 matchlen += (q[i] ? 8 : 0);
431 /* need to overwrite len/family portion as we don't compare them */
432 s.ss_len = sp->sa_len;
433 s.ss_family = sp->sa_family;
434 d.ss_len = dp->sa_len;
435 d.ss_family = dp->sa_family;
437 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
438 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
445 encap_fillarg(struct mbuf *m, void *arg)
450 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
452 *(void**)(tag+1) = arg;
453 m_tag_prepend(m, tag);
459 encap_getarg(struct mbuf *m)
464 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
466 p = *(void**)(tag+1);
467 m_tag_delete(m, tag);