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>
68 #include <sys/socket.h>
69 #include <sys/sockio.h>
71 #include <sys/errno.h>
72 #include <sys/protosw.h>
73 #include <sys/queue.h>
76 #include <net/route.h>
78 #include <netinet/in.h>
79 #include <netinet/in_systm.h>
80 #include <netinet/ip.h>
81 #include <netinet/ip_var.h>
82 #include <netinet/ip_encap.h>
85 #include <netinet/ip6.h>
86 #include <netinet6/ip6_var.h>
89 #include <machine/stdarg.h>
91 #include <sys/kernel.h>
92 #include <sys/malloc.h>
93 static MALLOC_DEFINE(M_NETADDR, "encap_export_host", "Export host address structure");
95 static void encap_add(struct encaptab *);
96 static int mask_match(const struct encaptab *, const struct sockaddr *,
97 const struct sockaddr *);
98 static void encap_fillarg(struct mbuf *, const struct encaptab *);
101 * All global variables in ip_encap.c are locked using encapmtx.
103 static struct mtx encapmtx;
104 MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
105 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(encaptab);
108 * We currently keey encap_init() for source code compatibility reasons --
109 * it's referenced by KAME pieces in netinet6.
118 encap4_input(struct mbuf **mp, int *offp, int proto)
122 struct sockaddr_in s, d;
123 const struct protosw *psw;
124 struct encaptab *ep, *match;
125 int matchprio, off, prio;
129 ip = mtod(m, struct ip *);
132 bzero(&s, sizeof(s));
133 s.sin_family = AF_INET;
134 s.sin_len = sizeof(struct sockaddr_in);
135 s.sin_addr = ip->ip_src;
136 bzero(&d, sizeof(d));
137 d.sin_family = AF_INET;
138 d.sin_len = sizeof(struct sockaddr_in);
139 d.sin_addr = ip->ip_dst;
144 LIST_FOREACH(ep, &encaptab, chain) {
145 if (ep->af != AF_INET)
147 if (ep->proto >= 0 && ep->proto != proto)
150 prio = (*ep->func)(m, off, proto, ep->arg);
153 * it's inbound traffic, we need to match in reverse
156 prio = mask_match(ep, (struct sockaddr *)&d,
157 (struct sockaddr *)&s);
161 * We prioritize the matches by using bit length of the
162 * matches. mask_match() and user-supplied matching function
163 * should return the bit length of the matches (for example,
164 * if both src/dst are matched for IPv4, 64 should be returned).
165 * 0 or negative return value means "it did not match".
167 * The question is, since we have two "mask" portion, we
168 * cannot really define total order between entries.
169 * For example, which of these should be preferred?
170 * mask_match() returns 48 (32 + 16) for both of them.
171 * src=3ffe::/16, dst=3ffe:501::/32
172 * src=3ffe:501::/32, dst=3ffe::/16
174 * We need to loop through all the possible candidates
175 * to get the best match - the search takes O(n) for
176 * n attachments (i.e. interfaces).
180 if (prio > matchprio) {
185 mtx_unlock(&encapmtx);
188 /* found a match, "match" has the best one */
190 if (psw && psw->pr_input) {
191 encap_fillarg(m, match);
193 (*psw->pr_input)(mp, offp, proto);
196 return (IPPROTO_DONE);
199 /* last resort: inject to raw socket */
201 return (rip_input(mp, offp, proto));
207 encap6_input(struct mbuf **mp, int *offp, int proto)
209 struct mbuf *m = *mp;
211 struct sockaddr_in6 s, d;
212 const struct protosw *psw;
213 struct encaptab *ep, *match;
216 ip6 = mtod(m, struct ip6_hdr *);
218 bzero(&s, sizeof(s));
219 s.sin6_family = AF_INET6;
220 s.sin6_len = sizeof(struct sockaddr_in6);
221 s.sin6_addr = ip6->ip6_src;
222 bzero(&d, sizeof(d));
223 d.sin6_family = AF_INET6;
224 d.sin6_len = sizeof(struct sockaddr_in6);
225 d.sin6_addr = ip6->ip6_dst;
230 LIST_FOREACH(ep, &encaptab, chain) {
231 if (ep->af != AF_INET6)
233 if (ep->proto >= 0 && ep->proto != proto)
236 prio = (*ep->func)(m, *offp, proto, ep->arg);
239 * it's inbound traffic, we need to match in reverse
242 prio = mask_match(ep, (struct sockaddr *)&d,
243 (struct sockaddr *)&s);
246 /* see encap4_input() for issues here */
249 if (prio > matchprio) {
254 mtx_unlock(&encapmtx);
259 if (psw && psw->pr_input) {
260 encap_fillarg(m, match);
261 return (*psw->pr_input)(mp, offp, proto);
268 /* last resort: inject to raw socket */
269 return rip6_input(mp, offp, proto);
273 /*lint -sem(encap_add, custodial(1)) */
275 encap_add(struct encaptab *ep)
278 mtx_assert(&encapmtx, MA_OWNED);
279 LIST_INSERT_HEAD(&encaptab, ep, chain);
283 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
284 * length of mask (sm and dm) is assumed to be same as sp/dp.
285 * Return value will be necessary as input (cookie) for encap_detach().
287 const struct encaptab *
288 encap_attach(int af, int proto, const struct sockaddr *sp,
289 const struct sockaddr *sm, const struct sockaddr *dp,
290 const struct sockaddr *dm, const struct protosw *psw, void *arg)
294 /* sanity check on args */
295 if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst))
297 if (sp->sa_len != dp->sa_len)
299 if (af != sp->sa_family || af != dp->sa_family)
302 /* check if anyone have already attached with exactly same config */
304 LIST_FOREACH(ep, &encaptab, chain) {
307 if (ep->proto != proto)
309 if (ep->src.ss_len != sp->sa_len ||
310 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
311 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
313 if (ep->dst.ss_len != dp->sa_len ||
314 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
315 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
318 mtx_unlock(&encapmtx);
322 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
324 mtx_unlock(&encapmtx);
327 bzero(ep, sizeof(*ep));
331 bcopy(sp, &ep->src, sp->sa_len);
332 bcopy(sm, &ep->srcmask, sp->sa_len);
333 bcopy(dp, &ep->dst, dp->sa_len);
334 bcopy(dm, &ep->dstmask, dp->sa_len);
339 mtx_unlock(&encapmtx);
343 const struct encaptab *
344 encap_attach_func(int af, int proto,
345 int (*func)(const struct mbuf *, int, int, void *),
346 const struct protosw *psw, void *arg)
350 /* sanity check on args */
354 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
357 bzero(ep, sizeof(*ep));
367 mtx_unlock(&encapmtx);
372 encap_detach(const struct encaptab *cookie)
374 const struct encaptab *ep = cookie;
378 LIST_FOREACH(p, &encaptab, chain) {
380 LIST_REMOVE(p, chain);
381 mtx_unlock(&encapmtx);
382 free(p, M_NETADDR); /*XXX*/
386 mtx_unlock(&encapmtx);
392 mask_match(const struct encaptab *ep, const struct sockaddr *sp,
393 const struct sockaddr *dp)
395 struct sockaddr_storage s;
396 struct sockaddr_storage d;
398 const u_int8_t *p, *q;
402 if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
404 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
406 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
411 p = (const u_int8_t *)sp;
412 q = (const u_int8_t *)&ep->srcmask;
414 for (i = 0 ; i < sp->sa_len; i++) {
417 matchlen += (q[i] ? 8 : 0);
420 p = (const u_int8_t *)dp;
421 q = (const u_int8_t *)&ep->dstmask;
423 for (i = 0 ; i < dp->sa_len; i++) {
425 /* XXX rough estimate */
426 matchlen += (q[i] ? 8 : 0);
429 /* need to overwrite len/family portion as we don't compare them */
430 s.ss_len = sp->sa_len;
431 s.ss_family = sp->sa_family;
432 d.ss_len = dp->sa_len;
433 d.ss_family = dp->sa_family;
435 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
436 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
443 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
447 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof (void*), M_NOWAIT);
449 *(void**)(tag+1) = ep->arg;
450 m_tag_prepend(m, tag);
455 encap_getarg(struct mbuf *m)
460 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
462 p = *(void**)(tag+1);
463 m_tag_delete(m, tag);