2 /* $KAME: ipcomp_output.c,v 1.24 2001/07/26 06:53:18 jinmei 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 <netkey/key.h>
78 #include <netkey/keydb.h>
80 #include <machine/stdarg.h>
82 #include <net/net_osdep.h>
84 static int ipcomp_output __P((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(m, nexthdrp, md, isr, af)
110 struct ipsecrequest *isr;
117 struct ipcomp *ipcomp;
118 struct secasvar *sav = isr->sav;
119 const struct ipcomp_algorithm *algo;
120 u_int16_t cpi; /* host order */
121 size_t plen0, plen; /* payload length to be compressed */
125 struct ipsecstat *stat;
141 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
142 return 0; /* no change at all */
145 /* grab parameters */
146 algo = ipcomp_algorithm_lookup(sav->alg_enc);
147 if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
152 if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
155 cpi = ntohl(sav->spi) & 0xffff;
157 /* compute original payload length */
159 for (n = md; n; n = n->m_next)
162 /* if the payload is short enough, we don't need to compress */
163 if (plen < algo->minplen)
167 * retain the original packet for two purposes:
168 * (1) we need to backout our changes when compression is not necessary.
169 * (2) byte lifetime computation should use the original packet.
170 * see RFC2401 page 23.
171 * compromise two m_copym(). we will be going through every byte of
172 * the payload during compression process anyways.
174 mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
179 md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
187 /* make the packet over-writable */
188 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
190 if (mprev == NULL || mprev->m_next != md) {
191 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
199 mprev->m_next = NULL;
200 if ((md = ipsec_copypkt(md)) == NULL) {
209 /* compress data part */
210 if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
211 ipseclog((LOG_ERR, "packet compression failure\n"));
219 stat->out_comphist[sav->alg_enc]++;
223 * if the packet became bigger, meaningless to use IPComp.
224 * we've only wasted our cpu time.
234 * no need to backout change beyond here.
239 m->m_pkthdr.len -= plen0;
240 m->m_pkthdr.len += plen;
244 * insert IPComp header.
247 struct ip *ip = NULL;
250 struct ip6_hdr *ip6 = NULL;
252 size_t hlen = 0; /* ip header len */
253 size_t complen = sizeof(struct ipcomp);
258 ip = mtod(m, struct ip *);
260 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
262 hlen = ip->ip_hl << 2;
268 ip6 = mtod(m, struct ip6_hdr *);
274 compoff = m->m_pkthdr.len - plen;
277 * grow the mbuf to accomodate ipcomp header.
278 * before: IP ... payload
279 * after: IP ... ipcomp payload
281 if (M_LEADINGSPACE(md) < complen) {
282 MGET(n, M_DONTWAIT, MT_DATA);
291 m->m_pkthdr.len += complen;
292 ipcomp = mtod(n, struct ipcomp *);
294 md->m_len += complen;
295 md->m_data -= complen;
296 m->m_pkthdr.len += complen;
297 ipcomp = mtod(md, struct ipcomp *);
300 bzero(ipcomp, sizeof(*ipcomp));
301 ipcomp->comp_nxt = *nexthdrp;
302 *nexthdrp = IPPROTO_IPCOMP;
303 ipcomp->comp_cpi = htons(cpi);
307 if (compoff + complen + plen < IP_MAXPACKET)
308 ip->ip_len = htons(compoff + complen + plen);
311 "IPv4 ESP output: size exceeds limit\n"));
312 ipsecstat.out_inval++;
321 /* total packet length will be computed in ip6_output() */
329 "NULL mbuf after compression in ipcomp%d_output",
335 /* compute byte lifetime against original packet */
336 key_sa_recordxfer(sav, mcopy);
345 panic("something bad in ipcomp_output");
351 ipcomp4_output(m, isr)
353 struct ipsecrequest *isr;
356 if (m->m_len < sizeof(struct ip)) {
357 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
358 ipsecstat.out_inval++;
362 ip = mtod(m, struct ip *);
363 /* XXX assumes that m->m_next points to payload */
364 return ipcomp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
370 ipcomp6_output(m, nexthdrp, md, isr)
374 struct ipsecrequest *isr;
376 if (m->m_len < sizeof(struct ip6_hdr)) {
377 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
378 ipsec6stat.out_inval++;
382 return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);