1 /* $FreeBSD: src/sys/netinet/ip_encap.c,v 1.1.2.5 2003/01/23 21:06:45 sam Exp $ */
2 /* $DragonFly: src/sys/netinet/ip_encap.c,v 1.15 2006/09/05 00:55:48 dillon Exp $ */
3 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
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34 * My grandfather said that there's a devil inside tunnelling technology...
36 * We have surprisingly many protocols that want packets with IP protocol
37 * #4 or #41. Here's a list of protocols that want protocol #41:
38 * RFC1933 configured tunnel
39 * RFC1933 automatic tunnel
40 * RFC2401 IPsec tunnel
41 * RFC2473 IPv6 generic packet tunnelling
42 * RFC2529 6over4 tunnel
43 * mobile-ip6 (uses RFC2473)
46 * Here's a list of protocol that want protocol #4:
47 * RFC1853 IPv4-in-IPv4 tunnelling
48 * RFC2003 IPv4 encapsulation within IPv4
49 * RFC2344 reverse tunnelling for mobile-ip4
50 * RFC2401 IPsec tunnel
51 * Well, what can I say. They impose different en/decapsulation mechanism
52 * from each other, so they need separate protocol handler. The only one
53 * we can easily determine by protocol # is IPsec, which always has
54 * AH/ESP/IPComp header right after outer IP header.
56 * So, clearly good old protosw does not work for protocol #4 and #41.
57 * The code will let you match protocol via src/dst address pair.
59 /* XXX is M_NETADDR correct? */
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 #include <sys/thread2.h>
95 MALLOC_DEFINE(M_NETADDR, "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 *, const struct encaptab *);
102 #ifndef LIST_HEAD_INITIALIZER
103 /* rely upon BSS initialization */
104 LIST_HEAD(, encaptab) encaptab;
106 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
109 int (*ipip_input)(struct mbuf **, int *, int); /* hook for mrouting */
114 static int initialized = 0;
121 * we cannot use LIST_INIT() here, since drivers may want to call
122 * encap_attach(), on driver attach. encap_init() will be called
123 * on AF_INET{,6} initialization, which happens after driver
124 * initialization - using LIST_INIT() here can nuke encap_attach()
127 LIST_INIT(&encaptab);
133 encap4_input(struct mbuf **mp, int *offp, int proto)
135 struct mbuf *m = *mp;
138 struct sockaddr_in s, d;
139 const struct protosw *psw;
140 struct encaptab *ep, *match;
143 ip = mtod(m, struct ip *);
147 s.sin_family = AF_INET;
148 s.sin_len = sizeof(struct sockaddr_in);
149 s.sin_addr = ip->ip_src;
151 d.sin_family = AF_INET;
152 d.sin_len = sizeof(struct sockaddr_in);
153 d.sin_addr = ip->ip_dst;
157 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
158 if (ep->af != AF_INET)
160 if (ep->proto >= 0 && ep->proto != proto)
163 prio = (*ep->func)(m, off, proto, ep->arg);
166 * it's inbound traffic, we need to match in reverse
169 prio = mask_match(ep,
170 (struct sockaddr *)&d,
171 (struct sockaddr *)&s);
175 * We prioritize the matches by using bit length of the
176 * matches. mask_match() and user-supplied matching function
177 * should return the bit length of the matches (for example,
178 * if both src/dst are matched for IPv4, 64 should be returned).
179 * 0 or negative return value means "it did not match".
181 * The question is, since we have two "mask" portion, we
182 * cannot really define total order between entries.
183 * For example, which of these should be preferred?
184 * mask_match() returns 48 (32 + 16) for both of them.
185 * src=3ffe::/16, dst=3ffe:501::/32
186 * src=3ffe:501::/32, dst=3ffe::/16
188 * We need to loop through all the possible candidates
189 * to get the best match - the search takes O(n) for
190 * n attachments (i.e. interfaces).
194 if (prio > matchprio) {
201 /* found a match, "match" has the best one */
203 if (psw && psw->pr_input) {
204 encap_fillarg(m, match);
206 (*psw->pr_input)(mp, offp, proto);
210 return(IPPROTO_DONE);
213 /* for backward compatibility */
214 if (proto == IPPROTO_IPV4 && ipip_input) {
216 ipip_input(mp, offp, proto);
217 return(IPPROTO_DONE);
220 /* last resort: inject to raw socket */
222 rip_input(mp, offp, proto);
223 return(IPPROTO_DONE);
229 encap6_input(struct mbuf **mp, int *offp, int proto)
231 struct mbuf *m = *mp;
233 struct sockaddr_in6 s, d;
234 const struct protosw *psw;
235 struct encaptab *ep, *match;
238 ip6 = mtod(m, struct ip6_hdr *);
241 s.sin6_family = AF_INET6;
242 s.sin6_len = sizeof(struct sockaddr_in6);
243 s.sin6_addr = ip6->ip6_src;
245 d.sin6_family = AF_INET6;
246 d.sin6_len = sizeof(struct sockaddr_in6);
247 d.sin6_addr = ip6->ip6_dst;
251 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
252 if (ep->af != AF_INET6)
254 if (ep->proto >= 0 && ep->proto != proto)
257 prio = (*ep->func)(m, *offp, proto, ep->arg);
260 * it's inbound traffic, we need to match in reverse
263 prio = mask_match(ep, (struct sockaddr *)&d,
264 (struct sockaddr *)&s);
267 /* see encap4_input() for issues here */
270 if (prio > matchprio) {
279 if (psw && psw->pr_input) {
280 encap_fillarg(m, match);
281 return (*psw->pr_input)(mp, offp, proto);
288 /* last resort: inject to raw socket */
289 return rip6_input(mp, offp, proto);
294 encap_add(struct encaptab *ep)
297 LIST_INSERT_HEAD(&encaptab, ep, chain);
301 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
302 * length of mask (sm and dm) is assumed to be same as sp/dp.
303 * Return value will be necessary as input (cookie) for encap_detach().
305 const struct encaptab *
306 encap_attach(int af, int proto, const struct sockaddr *sp,
307 const struct sockaddr *sm, const struct sockaddr *dp,
308 const struct sockaddr *dm, const struct protosw *psw, void *arg)
314 /* sanity check on args */
315 if (sp->sa_len > sizeof ep->src || dp->sa_len > sizeof ep->dst) {
319 if (sp->sa_len != dp->sa_len) {
323 if (af != sp->sa_family || af != dp->sa_family) {
328 /* check if anyone have already attached with exactly same config */
329 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
332 if (ep->proto != proto)
334 if (ep->src.ss_len != sp->sa_len ||
335 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
336 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
338 if (ep->dst.ss_len != dp->sa_len ||
339 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
340 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
347 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
355 bcopy(sp, &ep->src, sp->sa_len);
356 bcopy(sm, &ep->srcmask, sp->sa_len);
357 bcopy(dp, &ep->dst, dp->sa_len);
358 bcopy(dm, &ep->dstmask, dp->sa_len);
373 const struct encaptab *
374 encap_attach_func(int af, int proto,
375 int (*func)(const struct mbuf *, int, int, void *),
376 const struct protosw *psw, void *arg)
382 /* sanity check on args */
388 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
412 encap_detach(const struct encaptab *cookie)
414 const struct encaptab *ep = cookie;
417 for (p = LIST_FIRST(&encaptab); p; p = LIST_NEXT(p, chain)) {
419 LIST_REMOVE(p, chain);
420 kfree(p, M_NETADDR); /*XXX*/
429 mask_match(const struct encaptab *ep, const struct sockaddr *sp,
430 const struct sockaddr *dp)
432 struct sockaddr_storage s;
433 struct sockaddr_storage d;
435 const u_int8_t *p, *q;
439 if (sp->sa_len > sizeof s || dp->sa_len > sizeof d)
441 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
443 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
448 p = (const u_int8_t *)sp;
449 q = (const u_int8_t *)&ep->srcmask;
451 for (i = 0 ; i < sp->sa_len; i++) {
454 matchlen += (q[i] ? 8 : 0);
457 p = (const u_int8_t *)dp;
458 q = (const u_int8_t *)&ep->dstmask;
460 for (i = 0 ; i < dp->sa_len; i++) {
462 /* XXX rough estimate */
463 matchlen += (q[i] ? 8 : 0);
466 /* need to overwrite len/family portion as we don't compare them */
467 s.ss_len = sp->sa_len;
468 s.ss_family = sp->sa_family;
469 d.ss_len = dp->sa_len;
470 d.ss_family = dp->sa_family;
472 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
473 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
480 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
484 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), MB_DONTWAIT);
486 *(void **)m_tag_data(tag) = ep->arg;
487 m_tag_prepend(m, tag);
492 encap_getarg(struct mbuf *m)
497 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
499 p = *(void **)m_tag_data(tag);
500 m_tag_delete(m, tag);