2 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
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33 * My grandfather said that there's a devil inside tunnelling technology...
35 * We have surprisingly many protocols that want packets with IP protocol
36 * #4 or #41. Here's a list of protocols that want protocol #41:
37 * RFC1933 configured tunnel
38 * RFC1933 automatic tunnel
39 * RFC2401 IPsec tunnel
40 * RFC2473 IPv6 generic packet tunnelling
41 * RFC2529 6over4 tunnel
42 * mobile-ip6 (uses RFC2473)
45 * Here's a list of protocol that want protocol #4:
46 * RFC1853 IPv4-in-IPv4 tunnelling
47 * RFC2003 IPv4 encapsulation within IPv4
48 * RFC2344 reverse tunnelling for mobile-ip4
49 * RFC2401 IPsec tunnel
50 * Well, what can I say. They impose different en/decapsulation mechanism
51 * from each other, so they need separate protocol handler. The only one
52 * we can easily determine by protocol # is IPsec, which always has
53 * AH/ESP/IPComp header right after outer IP header.
55 * So, clearly good old protosw does not work for protocol #4 and #41.
56 * The code will let you match protocol via src/dst address pair.
58 /* XXX is M_NETADDR correct? */
60 #include "opt_mrouting.h"
62 #include "opt_inet6.h"
64 #include <sys/param.h>
65 #include <sys/systm.h>
66 #include <sys/socket.h>
67 #include <sys/sockio.h>
69 #include <sys/errno.h>
70 #include <sys/protosw.h>
71 #include <sys/queue.h>
74 #include <net/route.h>
76 #include <netinet/in.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/ip.h>
79 #include <netinet/ip_var.h>
80 #include <netinet/ip_encap.h>
83 #include <netinet/ip6.h>
84 #include <netinet6/ip6_var.h>
85 #include <netinet6/ip6protosw.h>
88 #include <machine/stdarg.h>
90 #include <net/net_osdep.h>
92 #include <sys/kernel.h>
93 #include <sys/malloc.h>
94 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
96 static void encap_add(struct encaptab *);
97 static int mask_match(const struct encaptab *, const struct sockaddr *,
98 const struct sockaddr *);
99 static void encap_fillarg(struct mbuf *, const struct encaptab *);
101 #ifndef LIST_HEAD_INITIALIZER
102 /* rely upon BSS initialization */
103 LIST_HEAD(, encaptab) encaptab;
105 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
111 static int initialized = 0;
118 * we cannot use LIST_INIT() here, since drivers may want to call
119 * encap_attach(), on driver attach. encap_init() will be called
120 * on AF_INET{,6} initialization, which happens after driver
121 * initialization - using LIST_INIT() here can nuke encap_attach()
124 LIST_INIT(&encaptab);
136 struct sockaddr_in s, d;
137 const struct protosw *psw;
138 struct encaptab *ep, *match;
141 ip = mtod(m, struct ip *);
144 bzero(&s, sizeof(s));
145 s.sin_family = AF_INET;
146 s.sin_len = sizeof(struct sockaddr_in);
147 s.sin_addr = ip->ip_src;
148 bzero(&d, sizeof(d));
149 d.sin_family = AF_INET;
150 d.sin_len = sizeof(struct sockaddr_in);
151 d.sin_addr = ip->ip_dst;
155 LIST_FOREACH(ep, &encaptab, chain) {
156 if (ep->af != AF_INET)
158 if (ep->proto >= 0 && ep->proto != proto)
161 prio = (*ep->func)(m, off, proto, ep->arg);
164 * it's inbound traffic, we need to match in reverse
167 prio = mask_match(ep, (struct sockaddr *)&d,
168 (struct sockaddr *)&s);
172 * We prioritize the matches by using bit length of the
173 * matches. mask_match() and user-supplied matching function
174 * should return the bit length of the matches (for example,
175 * if both src/dst are matched for IPv4, 64 should be returned).
176 * 0 or negative return value means "it did not match".
178 * The question is, since we have two "mask" portion, we
179 * cannot really define total order between entries.
180 * For example, which of these should be preferred?
181 * mask_match() returns 48 (32 + 16) for both of them.
182 * src=3ffe::/16, dst=3ffe:501::/32
183 * src=3ffe:501::/32, dst=3ffe::/16
185 * We need to loop through all the possible candidates
186 * to get the best match - the search takes O(n) for
187 * n attachments (i.e. interfaces).
191 if (prio > matchprio) {
198 /* found a match, "match" has the best one */
200 if (psw && psw->pr_input) {
201 encap_fillarg(m, match);
202 (*psw->pr_input)(m, off);
208 /* last resort: inject to raw socket */
215 encap6_input(mp, offp, proto)
220 struct mbuf *m = *mp;
222 struct sockaddr_in6 s, d;
223 const struct ip6protosw *psw;
224 struct encaptab *ep, *match;
227 ip6 = mtod(m, struct ip6_hdr *);
229 bzero(&s, sizeof(s));
230 s.sin6_family = AF_INET6;
231 s.sin6_len = sizeof(struct sockaddr_in6);
232 s.sin6_addr = ip6->ip6_src;
233 bzero(&d, sizeof(d));
234 d.sin6_family = AF_INET6;
235 d.sin6_len = sizeof(struct sockaddr_in6);
236 d.sin6_addr = ip6->ip6_dst;
240 LIST_FOREACH(ep, &encaptab, chain) {
241 if (ep->af != AF_INET6)
243 if (ep->proto >= 0 && ep->proto != proto)
246 prio = (*ep->func)(m, *offp, proto, ep->arg);
249 * it's inbound traffic, we need to match in reverse
252 prio = mask_match(ep, (struct sockaddr *)&d,
253 (struct sockaddr *)&s);
256 /* see encap4_input() for issues here */
259 if (prio > matchprio) {
267 psw = (const struct ip6protosw *)match->psw;
268 if (psw && psw->pr_input) {
269 encap_fillarg(m, match);
270 return (*psw->pr_input)(mp, offp, proto);
277 /* last resort: inject to raw socket */
278 return rip6_input(mp, offp, proto);
287 LIST_INSERT_HEAD(&encaptab, ep, chain);
291 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
292 * length of mask (sm and dm) is assumed to be same as sp/dp.
293 * Return value will be necessary as input (cookie) for encap_detach().
295 const struct encaptab *
296 encap_attach(af, proto, sp, sm, dp, dm, psw, arg)
299 const struct sockaddr *sp, *sm;
300 const struct sockaddr *dp, *dm;
301 const struct protosw *psw;
309 /* sanity check on args */
310 if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst)) {
314 if (sp->sa_len != dp->sa_len) {
318 if (af != sp->sa_family || af != dp->sa_family) {
323 /* check if anyone have already attached with exactly same config */
324 LIST_FOREACH(ep, &encaptab, chain) {
327 if (ep->proto != proto)
329 if (ep->src.ss_len != sp->sa_len ||
330 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
331 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
333 if (ep->dst.ss_len != dp->sa_len ||
334 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
335 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
342 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
347 bzero(ep, sizeof(*ep));
351 bcopy(sp, &ep->src, sp->sa_len);
352 bcopy(sm, &ep->srcmask, sp->sa_len);
353 bcopy(dp, &ep->dst, dp->sa_len);
354 bcopy(dm, &ep->dstmask, dp->sa_len);
369 const struct encaptab *
370 encap_attach_func(af, proto, func, psw, arg)
373 int (*func)(const struct mbuf *, int, int, void *);
374 const struct protosw *psw;
382 /* sanity check on args */
388 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
393 bzero(ep, sizeof(*ep));
414 const struct encaptab *cookie;
416 const struct encaptab *ep = cookie;
419 LIST_FOREACH(p, &encaptab, chain) {
421 LIST_REMOVE(p, chain);
422 free(p, M_NETADDR); /*XXX*/
431 mask_match(ep, sp, dp)
432 const struct encaptab *ep;
433 const struct sockaddr *sp;
434 const struct sockaddr *dp;
436 struct sockaddr_storage s;
437 struct sockaddr_storage d;
439 const u_int8_t *p, *q;
443 if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
445 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
447 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
452 p = (const u_int8_t *)sp;
453 q = (const u_int8_t *)&ep->srcmask;
455 for (i = 0 ; i < sp->sa_len; i++) {
458 matchlen += (q[i] ? 8 : 0);
461 p = (const u_int8_t *)dp;
462 q = (const u_int8_t *)&ep->dstmask;
464 for (i = 0 ; i < dp->sa_len; i++) {
466 /* XXX rough estimate */
467 matchlen += (q[i] ? 8 : 0);
470 /* need to overwrite len/family portion as we don't compare them */
471 s.ss_len = sp->sa_len;
472 s.ss_family = sp->sa_family;
473 d.ss_len = dp->sa_len;
474 d.ss_family = dp->sa_family;
476 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
477 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
486 const struct encaptab *ep;
489 m->m_pkthdr.aux = ep->arg;
493 n = m_aux_add(m, AF_INET, IPPROTO_IPV4);
495 *mtod(n, void **) = ep->arg;
496 n->m_len = sizeof(void *);
508 m->m_pkthdr.aux = NULL;
514 n = m_aux_find(m, AF_INET, IPPROTO_IPV4);
516 if (n->m_len == sizeof(void *))
517 p = *mtod(n, void **);