1 /* $FreeBSD: src/sys/netinet6/ipcomp_output.c,v 1.1.2.4 2003/04/29 08:33:50 suz Exp $ */
2 /* $KAME: ipcomp_output.c,v 1.25 2002/06/09 14:44:00 itojun Exp $ */
5 * Copyright (C) 1999 WIDE Project.
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34 * RFC2393 IP payload compression protocol (IPComp).
38 #include "opt_inet6.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/malloc.h>
44 #include <sys/domain.h>
45 #include <sys/protosw.h>
46 #include <sys/socket.h>
47 #include <sys/errno.h>
49 #include <sys/syslog.h>
52 #include <net/route.h>
53 #include <net/netisr.h>
55 #include <machine/cpu.h>
57 #include <netinet/in.h>
58 #include <netinet/in_systm.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/ip_ecn.h>
65 #include <netinet/ip6.h>
66 #include <netinet6/ip6_var.h>
68 #include <netinet6/ipcomp.h>
70 #include <netinet6/ipcomp6.h>
73 #include <netinet6/ipsec.h>
75 #include <netinet6/ipsec6.h>
77 #include <netproto/key/key.h>
78 #include <netproto/key/keydb.h>
80 #include <machine/stdarg.h>
82 #include <net/net_osdep.h>
84 static int ipcomp_output (struct mbuf *, u_char *, struct mbuf *,
85 struct ipsecrequest *, int);
88 * Modify the packet so that the payload is compressed.
89 * The mbuf (m) must start with IPv4 or IPv6 header.
90 * On failure, free the given mbuf and return non-zero.
95 * IP ......... payload
96 * during the encryption:
99 * IP ............... ipcomp payload
103 * <-----------------> compoff
106 ipcomp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
107 struct ipsecrequest *isr, int af)
113 struct ipcomp *ipcomp;
114 struct secasvar *sav = isr->sav;
115 const struct ipcomp_algorithm *algo;
116 u_int16_t cpi; /* host order */
117 size_t plen0, plen; /* payload length to be compressed */
121 struct ipsecstat *stat;
137 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
138 return 0; /* no change at all */
141 /* grab parameters */
142 algo = ipcomp_algorithm_lookup(sav->alg_enc);
143 if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
148 if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
151 cpi = ntohl(sav->spi) & 0xffff;
153 /* compute original payload length */
155 for (n = md; n; n = n->m_next)
158 /* if the payload is short enough, we don't need to compress */
159 if (plen < algo->minplen)
163 * retain the original packet for two purposes:
164 * (1) we need to backout our changes when compression is not necessary.
165 * (2) byte lifetime computation should use the original packet.
166 * see RFC2401 page 23.
167 * compromise two m_copym(). we will be going through every byte of
168 * the payload during compression process anyways.
170 mcopy = m_copym(m, 0, M_COPYALL, MB_DONTWAIT);
175 md0 = m_copym(md, 0, M_COPYALL, MB_DONTWAIT);
183 /* make the packet over-writable */
184 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
186 if (mprev == NULL || mprev->m_next != md) {
187 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
195 mprev->m_next = NULL;
196 if ((md = ipsec_copypkt(md)) == NULL) {
205 /* compress data part */
206 if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
207 ipseclog((LOG_ERR, "packet compression failure\n"));
215 stat->out_comphist[sav->alg_enc]++;
219 * if the packet became bigger, meaningless to use IPComp.
220 * we've only wasted our cpu time.
230 * no need to backout change beyond here.
235 m->m_pkthdr.len -= plen0;
236 m->m_pkthdr.len += plen;
240 * insert IPComp header.
243 struct ip *ip = NULL;
245 size_t complen = sizeof(struct ipcomp);
250 ip = mtod(m, struct ip *);
259 compoff = m->m_pkthdr.len - plen;
262 * grow the mbuf to accomodate ipcomp header.
263 * before: IP ... payload
264 * after: IP ... ipcomp payload
266 if (M_LEADINGSPACE(md) < complen) {
267 MGET(n, MB_DONTWAIT, MT_DATA);
276 m->m_pkthdr.len += complen;
277 ipcomp = mtod(n, struct ipcomp *);
279 md->m_len += complen;
280 md->m_data -= complen;
281 m->m_pkthdr.len += complen;
282 ipcomp = mtod(md, struct ipcomp *);
285 bzero(ipcomp, sizeof(*ipcomp));
286 ipcomp->comp_nxt = *nexthdrp;
287 *nexthdrp = IPPROTO_IPCOMP;
288 ipcomp->comp_cpi = htons(cpi);
292 if (compoff + complen + plen < IP_MAXPACKET)
293 ip->ip_len = htons(compoff + complen + plen);
296 "IPv4 ESP output: size exceeds limit\n"));
297 ipsecstat.out_inval++;
306 /* total packet length will be computed in ip6_output() */
314 "NULL mbuf after compression in ipcomp%d_output",
320 /* compute byte lifetime against original packet */
321 key_sa_recordxfer(sav, mcopy);
330 panic("something bad in ipcomp_output");
336 ipcomp4_output(struct mbuf *m, struct ipsecrequest *isr)
339 if (m->m_len < sizeof(struct ip)) {
340 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
341 ipsecstat.out_inval++;
345 ip = mtod(m, struct ip *);
346 /* XXX assumes that m->m_next points to payload */
347 return ipcomp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
353 ipcomp6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
354 struct ipsecrequest *isr)
356 if (m->m_len < sizeof(struct ip6_hdr)) {
357 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
358 ipsec6stat.out_inval++;
362 return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);