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 $ */
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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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.
60 #include "opt_inet6.h"
62 #include <sys/param.h>
63 #include <sys/systm.h>
64 #include <sys/socket.h>
65 #include <sys/sockio.h>
67 #include <sys/errno.h>
68 #include <sys/protosw.h>
69 #include <sys/queue.h>
72 #include <net/route.h>
74 #include <netinet/in.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/ip.h>
77 #include <netinet/ip_var.h>
78 #include <netinet/ip_encap.h>
81 #include <netinet/ip6.h>
82 #include <netinet6/ip6_var.h>
83 #include <netinet6/ip6protosw.h>
86 #include <machine/stdarg.h>
88 #include <net/net_osdep.h>
90 #include <sys/kernel.h>
91 #include <sys/malloc.h>
92 #include <sys/thread2.h>
93 MALLOC_DEFINE(M_IPENCAP
, "IP Encapsulation", "IP Encapsulation");
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
*);
100 #ifndef LIST_HEAD_INITIALIZER
101 /* rely upon BSS initialization */
102 LIST_HEAD(, encaptab
) encaptab
;
104 LIST_HEAD(, encaptab
) encaptab
= LIST_HEAD_INITIALIZER(&encaptab
);
107 int (*ipip_input
)(struct mbuf
**, int *, int); /* hook for mrouting */
112 static int initialized
= 0;
119 * we cannot use LIST_INIT() here, since drivers may want to call
120 * encap_attach(), on driver attach. encap_init() will be called
121 * on AF_INET{,6} initialization, which happens after driver
122 * initialization - using LIST_INIT() here can nuke encap_attach()
125 LIST_INIT(&encaptab
);
131 encap4_input(struct mbuf
**mp
, int *offp
, int proto
)
133 struct mbuf
*m
= *mp
;
136 struct sockaddr_in s
, d
;
137 const struct protosw
*psw
;
138 struct encaptab
*ep
, *match
;
141 ip
= mtod(m
, struct ip
*);
145 s
.sin_family
= AF_INET
;
146 s
.sin_len
= sizeof(struct sockaddr_in
);
147 s
.sin_addr
= ip
->ip_src
;
149 d
.sin_family
= AF_INET
;
150 d
.sin_len
= sizeof(struct sockaddr_in
);
151 d
.sin_addr
= ip
->ip_dst
;
155 for (ep
= LIST_FIRST(&encaptab
); ep
; ep
= LIST_NEXT(ep
, 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
,
168 (struct sockaddr
*)&d
,
169 (struct sockaddr
*)&s
);
173 * We prioritize the matches by using bit length of the
174 * matches. mask_match() and user-supplied matching function
175 * should return the bit length of the matches (for example,
176 * if both src/dst are matched for IPv4, 64 should be returned).
177 * 0 or negative return value means "it did not match".
179 * The question is, since we have two "mask" portion, we
180 * cannot really define total order between entries.
181 * For example, which of these should be preferred?
182 * mask_match() returns 48 (32 + 16) for both of them.
183 * src=3ffe::/16, dst=3ffe:501::/32
184 * src=3ffe:501::/32, dst=3ffe::/16
186 * We need to loop through all the possible candidates
187 * to get the best match - the search takes O(n) for
188 * n attachments (i.e. interfaces).
192 if (prio
> matchprio
) {
199 /* found a match, "match" has the best one */
201 if (psw
&& psw
->pr_input
) {
202 encap_fillarg(m
, match
);
204 (*psw
->pr_input
)(mp
, offp
, proto
);
208 return(IPPROTO_DONE
);
211 /* for backward compatibility */
212 if (proto
== IPPROTO_IPV4
&& ipip_input
) {
214 ipip_input(mp
, offp
, proto
);
215 return(IPPROTO_DONE
);
218 /* last resort: inject to raw socket */
220 rip_input(mp
, offp
, proto
);
221 return(IPPROTO_DONE
);
227 encap6_input(struct mbuf
**mp
, int *offp
, int proto
)
229 struct mbuf
*m
= *mp
;
231 struct sockaddr_in6 s
, d
;
232 const struct protosw
*psw
;
233 struct encaptab
*ep
, *match
;
236 ip6
= mtod(m
, struct ip6_hdr
*);
239 s
.sin6_family
= AF_INET6
;
240 s
.sin6_len
= sizeof(struct sockaddr_in6
);
241 s
.sin6_addr
= ip6
->ip6_src
;
243 d
.sin6_family
= AF_INET6
;
244 d
.sin6_len
= sizeof(struct sockaddr_in6
);
245 d
.sin6_addr
= ip6
->ip6_dst
;
249 for (ep
= LIST_FIRST(&encaptab
); ep
; ep
= LIST_NEXT(ep
, chain
)) {
250 if (ep
->af
!= AF_INET6
)
252 if (ep
->proto
>= 0 && ep
->proto
!= proto
)
255 prio
= (*ep
->func
)(m
, *offp
, proto
, ep
->arg
);
258 * it's inbound traffic, we need to match in reverse
261 prio
= mask_match(ep
, (struct sockaddr
*)&d
,
262 (struct sockaddr
*)&s
);
265 /* see encap4_input() for issues here */
268 if (prio
> matchprio
) {
277 if (psw
&& psw
->pr_input
) {
278 encap_fillarg(m
, match
);
279 return (*psw
->pr_input
)(mp
, offp
, proto
);
286 /* last resort: inject to raw socket */
287 return rip6_input(mp
, offp
, proto
);
292 encap_add(struct encaptab
*ep
)
295 LIST_INSERT_HEAD(&encaptab
, ep
, chain
);
299 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
300 * length of mask (sm and dm) is assumed to be same as sp/dp.
301 * Return value will be necessary as input (cookie) for encap_detach().
303 const struct encaptab
*
304 encap_attach(int af
, int proto
, const struct sockaddr
*sp
,
305 const struct sockaddr
*sm
, const struct sockaddr
*dp
,
306 const struct sockaddr
*dm
, const struct protosw
*psw
, void *arg
)
311 /* sanity check on args */
312 if (sp
->sa_len
> sizeof ep
->src
|| dp
->sa_len
> sizeof ep
->dst
)
314 if (sp
->sa_len
!= dp
->sa_len
)
316 if (af
!= sp
->sa_family
|| af
!= dp
->sa_family
)
319 /* check if anyone have already attached with exactly same config */
320 for (ep
= LIST_FIRST(&encaptab
); ep
; ep
= LIST_NEXT(ep
, chain
)) {
323 if (ep
->proto
!= proto
)
325 if (ep
->src
.ss_len
!= sp
->sa_len
||
326 bcmp(&ep
->src
, sp
, sp
->sa_len
) != 0 ||
327 bcmp(&ep
->srcmask
, sm
, sp
->sa_len
) != 0)
329 if (ep
->dst
.ss_len
!= dp
->sa_len
||
330 bcmp(&ep
->dst
, dp
, dp
->sa_len
) != 0 ||
331 bcmp(&ep
->dstmask
, dm
, dp
->sa_len
) != 0)
337 ep
= kmalloc(sizeof *ep
, M_IPENCAP
, M_INTWAIT
| M_ZERO
| M_NULLOK
);
343 bcopy(sp
, &ep
->src
, sp
->sa_len
);
344 bcopy(sm
, &ep
->srcmask
, sp
->sa_len
);
345 bcopy(dp
, &ep
->dst
, dp
->sa_len
);
346 bcopy(dm
, &ep
->dstmask
, dp
->sa_len
);
360 const struct encaptab
*
361 encap_attach_func(int af
, int proto
,
362 int (*func
)(const struct mbuf
*, int, int, void *),
363 const struct protosw
*psw
, void *arg
)
368 /* sanity check on args */
372 ep
= kmalloc(sizeof *ep
, M_IPENCAP
, M_INTWAIT
| M_ZERO
| M_NULLOK
);
393 encap_detach(const struct encaptab
*cookie
)
395 const struct encaptab
*ep
= cookie
;
398 for (p
= LIST_FIRST(&encaptab
); p
; p
= LIST_NEXT(p
, chain
)) {
400 LIST_REMOVE(p
, chain
);
401 kfree(p
, M_IPENCAP
); /*XXX*/
410 mask_match(const struct encaptab
*ep
, const struct sockaddr
*sp
,
411 const struct sockaddr
*dp
)
413 struct sockaddr_storage s
;
414 struct sockaddr_storage d
;
416 const u_int8_t
*p
, *q
;
420 if (sp
->sa_len
> sizeof s
|| dp
->sa_len
> sizeof d
)
422 if (sp
->sa_family
!= ep
->af
|| dp
->sa_family
!= ep
->af
)
424 if (sp
->sa_len
!= ep
->src
.ss_len
|| dp
->sa_len
!= ep
->dst
.ss_len
)
429 p
= (const u_int8_t
*)sp
;
430 q
= (const u_int8_t
*)&ep
->srcmask
;
432 for (i
= 0 ; i
< sp
->sa_len
; i
++) {
435 matchlen
+= (q
[i
] ? 8 : 0);
438 p
= (const u_int8_t
*)dp
;
439 q
= (const u_int8_t
*)&ep
->dstmask
;
441 for (i
= 0 ; i
< dp
->sa_len
; i
++) {
443 /* XXX rough estimate */
444 matchlen
+= (q
[i
] ? 8 : 0);
447 /* need to overwrite len/family portion as we don't compare them */
448 s
.ss_len
= sp
->sa_len
;
449 s
.ss_family
= sp
->sa_family
;
450 d
.ss_len
= dp
->sa_len
;
451 d
.ss_family
= dp
->sa_family
;
453 if (bcmp(&s
, &ep
->src
, ep
->src
.ss_len
) == 0 &&
454 bcmp(&d
, &ep
->dst
, ep
->dst
.ss_len
) == 0) {
461 encap_fillarg(struct mbuf
*m
, const struct encaptab
*ep
)
465 tag
= m_tag_get(PACKET_TAG_ENCAP
, sizeof(void *), M_NOWAIT
);
467 *(void **)m_tag_data(tag
) = ep
->arg
;
468 m_tag_prepend(m
, tag
);
473 encap_getarg(struct mbuf
*m
)
478 tag
= m_tag_find(m
, PACKET_TAG_ENCAP
, NULL
);
480 p
= *(void **)m_tag_data(tag
);
481 m_tag_delete(m
, tag
);