1 /* $FreeBSD: src/sys/netinet6/ah_output.c,v 1.1.2.5 2003/05/06 06:46:58 suz Exp $ */
2 /* $KAME: ah_output.c,v 1.31 2001/07/26 06:53:15 jinmei Exp $ */
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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34 * RFC1826/2402 authentication header.
38 #include "opt_inet6.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
43 #include <sys/domain.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
47 #include <sys/errno.h>
49 #include <sys/syslog.h>
52 #include <net/route.h>
54 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/in_var.h>
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet/icmp6.h>
66 #include <netinet6/ipsec.h>
68 #include <netinet6/ipsec6.h>
70 #include <netinet6/ah.h>
72 #include <netinet6/ah6.h>
74 #include <netproto/key/key.h>
75 #include <netproto/key/keydb.h>
77 #include <net/net_osdep.h>
80 static struct in_addr *ah4_finaldst (struct mbuf *);
84 * compute AH header size.
85 * transport mode only. for tunnel mode, we should implement
86 * virtual interface, and control MTU/MSS by the interface MTU.
89 ah_hdrsiz(struct ipsecrequest *isr)
91 const struct ah_algorithm *algo;
96 panic("ah_hdrsiz: NULL was passed.");
98 if (isr->saidx.proto != IPPROTO_AH)
99 panic("unsupported mode passed to ah_hdrsiz");
101 if (isr->sav == NULL)
103 if (isr->sav->state != SADB_SASTATE_MATURE
104 && isr->sav->state != SADB_SASTATE_DYING)
107 /* we need transport mode AH. */
108 algo = ah_algorithm_lookup(isr->sav->alg_auth);
114 * right now we don't calcurate the padding size. simply
115 * treat the padding size as constant, for simplicity.
117 * XXX variable size padding support
119 hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
120 if (isr->sav->flags & SADB_X_EXT_OLD)
121 hdrsiz += sizeof(struct ah);
123 hdrsiz += sizeof(struct newah);
129 * sizeof(struct newah) > sizeof(struct ah).
130 * 16 = (16 + 3) & ~(4 - 1).
132 return sizeof(struct newah) + 16;
137 * Modify the packet so that it includes the authentication data.
138 * The mbuf passed must start with IPv4 header.
140 * assumes that the first mbuf contains IPv4 header + option only.
141 * the function does not modify m.
144 ah4_output(struct mbuf *m, struct ipsecrequest *isr)
146 struct secasvar *sav = isr->sav;
147 const struct ah_algorithm *algo;
150 u_char *ahsumpos = NULL;
151 size_t hlen = 0; /* IP header+option in bytes */
152 size_t plen = 0; /* AH payload size in bytes */
153 size_t ahlen = 0; /* plen + sizeof(ah) */
156 struct in_addr *finaldst;
160 if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
163 ip = mtod(m, struct ip *);
164 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
165 "sav->replay is null: %x->%x, SPI=%u\n",
166 (u_int32_t)ntohl(ip->ip_src.s_addr),
167 (u_int32_t)ntohl(ip->ip_dst.s_addr),
168 (u_int32_t)ntohl(sav->spi)));
169 ipsecstat.out_inval++;
174 algo = ah_algorithm_lookup(sav->alg_auth);
176 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
177 "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
178 ipsecstat.out_inval++;
185 * determine the size to grow.
187 if (sav->flags & SADB_X_EXT_OLD) {
189 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
190 ahlen = plen + sizeof(struct ah);
193 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
194 ahlen = plen + sizeof(struct newah);
198 * grow the mbuf to accomodate AH.
200 ip = mtod(m, struct ip *);
202 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
204 hlen = ip->ip_hl << 2;
207 if (m->m_len != hlen)
208 panic("ah4_output: assumption failed (first mbuf length)");
209 if (M_LEADINGSPACE(m->m_next) < ahlen) {
211 MGET(n, M_NOWAIT, MT_DATA);
213 ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
219 n->m_next = m->m_next;
221 m->m_pkthdr.len += ahlen;
222 ahdrpos = mtod(n, u_char *);
224 m->m_next->m_len += ahlen;
225 m->m_next->m_data -= ahlen;
226 m->m_pkthdr.len += ahlen;
227 ahdrpos = mtod(m->m_next, u_char *);
230 ip = mtod(m, struct ip *); /* just to be sure */
235 if (sav->flags & SADB_X_EXT_OLD) {
238 ahdr = (struct ah *)ahdrpos;
239 ahsumpos = (u_char *)(ahdr + 1);
240 ahdr->ah_len = plen >> 2;
241 ahdr->ah_nxt = ip->ip_p;
242 ahdr->ah_reserve = htons(0);
244 bzero(ahdr + 1, plen);
248 ahdr = (struct newah *)ahdrpos;
249 ahsumpos = (u_char *)(ahdr + 1);
250 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
251 ahdr->ah_nxt = ip->ip_p;
252 ahdr->ah_reserve = htons(0);
254 if (sav->replay->count == ~0) {
255 if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
256 /* XXX Is it noisy ? */
257 ipseclog((LOG_WARNING,
258 "replay counter overflowed. %s\n",
259 ipsec_logsastr(sav)));
260 ipsecstat.out_inval++;
265 sav->replay->count++;
267 * XXX sequence number must not be cycled, if the SA is
268 * installed by IKE daemon.
270 ahdr->ah_seq = htonl(sav->replay->count & 0xffffffff);
271 bzero(ahdr + 1, plen);
275 * modify IPv4 header.
277 ip->ip_p = IPPROTO_AH;
278 if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
279 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
281 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
282 ipsecstat.out_inval++;
288 * If there is source routing option, update destination field in
289 * the IPv4 header to the final destination.
290 * Note that we do not need to update source routing option itself
291 * (as done in IPv4 AH processing -- see ip6_output()), since
292 * source routing option is not part of the ICV computation.
294 finaldst = ah4_finaldst(m);
296 dst.s_addr = ip->ip_dst.s_addr;
297 ip->ip_dst.s_addr = finaldst->s_addr;
299 dst.s_addr = 0; /* fix compiler warning */
303 * calcurate the checksum, based on security association
304 * and the algorithm specified.
306 error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
309 "error after ah4_calccksum, called from ah4_output"));
312 ipsecstat.out_inval++;
317 ip = mtod(m, struct ip *); /* just to make sure */
318 ip->ip_dst.s_addr = dst.s_addr;
320 ipsecstat.out_success++;
321 ipsecstat.out_ahhist[sav->alg_auth]++;
322 key_sa_recordxfer(sav, m);
328 /* Calculate AH length */
330 ah_hdrlen(struct secasvar *sav)
332 const struct ah_algorithm *algo;
335 algo = ah_algorithm_lookup(sav->alg_auth);
338 if (sav->flags & SADB_X_EXT_OLD) {
340 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
341 ahlen = plen + sizeof(struct ah);
344 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
345 ahlen = plen + sizeof(struct newah);
353 * Fill in the Authentication Header and calculate checksum.
356 ah6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
357 struct ipsecrequest *isr)
361 struct secasvar *sav = isr->sav;
362 const struct ah_algorithm *algo;
364 u_char *ahsumpos = NULL;
365 size_t plen; /* AH payload size in bytes */
370 if (m->m_len < sizeof(struct ip6_hdr)) {
371 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
376 ahlen = ah_hdrlen(sav);
380 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
382 if (!mprev || mprev->m_next != md) {
383 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
388 mah = m_getb(ahlen, M_NOWAIT, MT_DATA, 0);
396 m->m_pkthdr.len += ahlen;
399 if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
401 "ah6_output: AH with IPv6 jumbogram is not supported\n"));
405 ip6 = mtod(m, struct ip6_hdr *);
406 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
408 if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
409 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
410 "sav->replay is null: SPI=%u\n",
411 (u_int32_t)ntohl(sav->spi)));
412 ipsec6stat.out_inval++;
417 algo = ah_algorithm_lookup(sav->alg_auth);
419 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
420 "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
421 ipsec6stat.out_inval++;
430 if (sav->flags & SADB_X_EXT_OLD) {
431 struct ah *ahdr = mtod(mah, struct ah *);
433 plen = mah->m_len - sizeof(struct ah);
434 ahsumpos = (u_char *)(ahdr + 1);
435 ahdr->ah_nxt = *nexthdrp;
436 *nexthdrp = IPPROTO_AH;
437 ahdr->ah_len = plen >> 2;
438 ahdr->ah_reserve = htons(0);
440 bzero(ahdr + 1, plen);
442 struct newah *ahdr = mtod(mah, struct newah *);
444 plen = mah->m_len - sizeof(struct newah);
445 ahsumpos = (u_char *)(ahdr + 1);
446 ahdr->ah_nxt = *nexthdrp;
447 *nexthdrp = IPPROTO_AH;
448 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
449 ahdr->ah_reserve = htons(0);
451 if (sav->replay->count == ~0) {
452 if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
453 /* XXX Is it noisy ? */
454 ipseclog((LOG_WARNING,
455 "replay counter overflowed. %s\n",
456 ipsec_logsastr(sav)));
457 ipsec6stat.out_inval++;
462 sav->replay->count++;
464 * XXX sequence number must not be cycled, if the SA is
465 * installed by IKE daemon.
467 ahdr->ah_seq = htonl(sav->replay->count);
468 bzero(ahdr + 1, plen);
472 * calcurate the checksum, based on security association
473 * and the algorithm specified.
475 error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
477 ipsec6stat.out_inval++;
480 ipsec6stat.out_success++;
481 key_sa_recordxfer(sav, m);
483 ipsec6stat.out_ahhist[sav->alg_auth]++;
491 * Find the final destination if there is loose/strict source routing option.
492 * Returns NULL if there's no source routing options.
493 * Returns NULL on errors too.
494 * Note that this function will return a pointer INTO the given parameter,
496 * The mbuf must be pulled up toward, at least, ip option part.
498 static struct in_addr *
499 ah4_finaldst(struct mbuf *m)
508 panic("ah4_finaldst: m == NULL");
509 ip = mtod(m, struct ip *);
510 hlen = (ip->ip_hl << 2);
512 if (m->m_len < hlen) {
514 "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
518 if (hlen == sizeof(struct ip))
521 optlen = hlen - sizeof(struct ip);
523 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
528 q = (u_char *)(ip + 1);
531 if (i + IPOPT_OPTVAL >= optlen)
533 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
534 q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
535 i + IPOPT_OLEN < optlen)
540 switch (q[i + IPOPT_OPTVAL]) {
542 i = optlen; /* bye */
549 if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
550 optlen - i < q[i + IPOPT_OLEN]) {
552 "ip_finaldst: invalid IP option "
553 "(code=%02x len=%02x)\n",
554 q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
557 i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
558 return (struct in_addr *)(q + i);
560 if (q[i + IPOPT_OLEN] < 2 ||
561 optlen - i < q[i + IPOPT_OLEN]) {
563 "ip_finaldst: invalid IP option "
564 "(code=%02x len=%02x)\n",
565 q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
568 i += q[i + IPOPT_OLEN];