1 /* $FreeBSD: src/sys/netinet/ip_encap.c,v 1.1.2.5 2003/01/23 21:06:45 sam Exp $ */
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? */
61 #include "opt_inet6.h"
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/socket.h>
66 #include <sys/sockio.h>
68 #include <sys/errno.h>
69 #include <sys/protosw.h>
70 #include <sys/queue.h>
73 #include <net/route.h>
75 #include <netinet/in.h>
76 #include <netinet/in_systm.h>
77 #include <netinet/ip.h>
78 #include <netinet/ip_var.h>
79 #include <netinet/ip_encap.h>
82 #include <netinet/ip6.h>
83 #include <netinet6/ip6_var.h>
84 #include <netinet6/ip6protosw.h>
87 #include <machine/stdarg.h>
89 #include <net/net_osdep.h>
91 #include <sys/kernel.h>
92 #include <sys/malloc.h>
93 #include <sys/thread2.h>
94 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);
108 int (*ipip_input)(struct mbuf **, int *, int); /* hook for mrouting */
113 static int initialized = 0;
120 * we cannot use LIST_INIT() here, since drivers may want to call
121 * encap_attach(), on driver attach. encap_init() will be called
122 * on AF_INET{,6} initialization, which happens after driver
123 * initialization - using LIST_INIT() here can nuke encap_attach()
126 LIST_INIT(&encaptab);
132 encap4_input(struct mbuf **mp, int *offp, int proto)
134 struct mbuf *m = *mp;
137 struct sockaddr_in s, d;
138 const struct protosw *psw;
139 struct encaptab *ep, *match;
142 ip = mtod(m, struct ip *);
146 s.sin_family = AF_INET;
147 s.sin_len = sizeof(struct sockaddr_in);
148 s.sin_addr = ip->ip_src;
150 d.sin_family = AF_INET;
151 d.sin_len = sizeof(struct sockaddr_in);
152 d.sin_addr = ip->ip_dst;
156 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
157 if (ep->af != AF_INET)
159 if (ep->proto >= 0 && ep->proto != proto)
162 prio = (*ep->func)(m, off, proto, ep->arg);
165 * it's inbound traffic, we need to match in reverse
168 prio = mask_match(ep,
169 (struct sockaddr *)&d,
170 (struct sockaddr *)&s);
174 * We prioritize the matches by using bit length of the
175 * matches. mask_match() and user-supplied matching function
176 * should return the bit length of the matches (for example,
177 * if both src/dst are matched for IPv4, 64 should be returned).
178 * 0 or negative return value means "it did not match".
180 * The question is, since we have two "mask" portion, we
181 * cannot really define total order between entries.
182 * For example, which of these should be preferred?
183 * mask_match() returns 48 (32 + 16) for both of them.
184 * src=3ffe::/16, dst=3ffe:501::/32
185 * src=3ffe:501::/32, dst=3ffe::/16
187 * We need to loop through all the possible candidates
188 * to get the best match - the search takes O(n) for
189 * n attachments (i.e. interfaces).
193 if (prio > matchprio) {
200 /* found a match, "match" has the best one */
202 if (psw && psw->pr_input) {
203 encap_fillarg(m, match);
205 (*psw->pr_input)(mp, offp, proto);
209 return(IPPROTO_DONE);
212 /* for backward compatibility */
213 if (proto == IPPROTO_IPV4 && ipip_input) {
215 ipip_input(mp, offp, proto);
216 return(IPPROTO_DONE);
219 /* last resort: inject to raw socket */
221 rip_input(mp, offp, proto);
222 return(IPPROTO_DONE);
228 encap6_input(struct mbuf **mp, int *offp, int proto)
230 struct mbuf *m = *mp;
232 struct sockaddr_in6 s, d;
233 const struct protosw *psw;
234 struct encaptab *ep, *match;
237 ip6 = mtod(m, struct ip6_hdr *);
240 s.sin6_family = AF_INET6;
241 s.sin6_len = sizeof(struct sockaddr_in6);
242 s.sin6_addr = ip6->ip6_src;
244 d.sin6_family = AF_INET6;
245 d.sin6_len = sizeof(struct sockaddr_in6);
246 d.sin6_addr = ip6->ip6_dst;
250 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
251 if (ep->af != AF_INET6)
253 if (ep->proto >= 0 && ep->proto != proto)
256 prio = (*ep->func)(m, *offp, proto, ep->arg);
259 * it's inbound traffic, we need to match in reverse
262 prio = mask_match(ep, (struct sockaddr *)&d,
263 (struct sockaddr *)&s);
266 /* see encap4_input() for issues here */
269 if (prio > matchprio) {
278 if (psw && psw->pr_input) {
279 encap_fillarg(m, match);
280 return (*psw->pr_input)(mp, offp, proto);
287 /* last resort: inject to raw socket */
288 return rip6_input(mp, offp, proto);
293 encap_add(struct encaptab *ep)
296 LIST_INSERT_HEAD(&encaptab, ep, chain);
300 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
301 * length of mask (sm and dm) is assumed to be same as sp/dp.
302 * Return value will be necessary as input (cookie) for encap_detach().
304 const struct encaptab *
305 encap_attach(int af, int proto, const struct sockaddr *sp,
306 const struct sockaddr *sm, const struct sockaddr *dp,
307 const struct sockaddr *dm, const struct protosw *psw, void *arg)
312 /* sanity check on args */
313 if (sp->sa_len > sizeof ep->src || dp->sa_len > sizeof ep->dst)
315 if (sp->sa_len != dp->sa_len)
317 if (af != sp->sa_family || af != dp->sa_family)
320 /* check if anyone have already attached with exactly same config */
321 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
324 if (ep->proto != proto)
326 if (ep->src.ss_len != sp->sa_len ||
327 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
328 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
330 if (ep->dst.ss_len != dp->sa_len ||
331 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
332 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
338 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
344 bcopy(sp, &ep->src, sp->sa_len);
345 bcopy(sm, &ep->srcmask, sp->sa_len);
346 bcopy(dp, &ep->dst, dp->sa_len);
347 bcopy(dm, &ep->dstmask, dp->sa_len);
361 const struct encaptab *
362 encap_attach_func(int af, int proto,
363 int (*func)(const struct mbuf *, int, int, void *),
364 const struct protosw *psw, void *arg)
369 /* sanity check on args */
373 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
394 encap_detach(const struct encaptab *cookie)
396 const struct encaptab *ep = cookie;
399 for (p = LIST_FIRST(&encaptab); p; p = LIST_NEXT(p, chain)) {
401 LIST_REMOVE(p, chain);
402 kfree(p, M_NETADDR); /*XXX*/
411 mask_match(const struct encaptab *ep, const struct sockaddr *sp,
412 const struct sockaddr *dp)
414 struct sockaddr_storage s;
415 struct sockaddr_storage d;
417 const u_int8_t *p, *q;
421 if (sp->sa_len > sizeof s || dp->sa_len > sizeof d)
423 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
425 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
430 p = (const u_int8_t *)sp;
431 q = (const u_int8_t *)&ep->srcmask;
433 for (i = 0 ; i < sp->sa_len; i++) {
436 matchlen += (q[i] ? 8 : 0);
439 p = (const u_int8_t *)dp;
440 q = (const u_int8_t *)&ep->dstmask;
442 for (i = 0 ; i < dp->sa_len; i++) {
444 /* XXX rough estimate */
445 matchlen += (q[i] ? 8 : 0);
448 /* need to overwrite len/family portion as we don't compare them */
449 s.ss_len = sp->sa_len;
450 s.ss_family = sp->sa_family;
451 d.ss_len = dp->sa_len;
452 d.ss_family = dp->sa_family;
454 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
455 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
462 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
466 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
468 *(void **)m_tag_data(tag) = ep->arg;
469 m_tag_prepend(m, tag);
474 encap_getarg(struct mbuf *m)
479 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
481 p = *(void **)m_tag_data(tag);
482 m_tag_delete(m, tag);