2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
4 * Copyright (C)2003 USAGI/WIDE Project
6 * Author Mitsuru KANDA <mk@linux-ipv6.org>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 * The compression of IP datagram MUST be done before AH/ESP processing,
27 * fragmentation, and the addition of Hop-by-Hop/Routing header.
30 * The decompression of IP datagram MUST be done after the reassembly,
33 #include <linux/config.h>
34 #include <linux/module.h>
35 #include <net/inet_ecn.h>
38 #include <net/ipcomp.h>
39 #include <asm/scatterlist.h>
40 #include <linux/crypto.h>
41 #include <linux/pfkeyv2.h>
42 #include <linux/random.h>
45 #include <linux/ipv6.h>
46 #include <linux/icmpv6.h>
48 static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
53 int hdr_len = skb->h.raw - skb->nh.raw;
54 unsigned char *tmp_hdr = NULL;
57 struct ipcomp_data *ipcd = x->data;
58 u8 *start, *scratch = ipcd->scratch;
60 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
61 skb_linearize(skb, GFP_ATOMIC) != 0) {
66 skb->ip_summed = CHECKSUM_NONE;
68 /* Remove ipcomp header and decompress original payload */
70 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
73 memcpy(tmp_hdr, iph, hdr_len);
74 nexthdr = *(u8 *)skb->data;
75 skb_pull(skb, sizeof(struct ipv6_comp_hdr));
76 skb->nh.raw += sizeof(struct ipv6_comp_hdr);
77 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
79 iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
80 skb->h.raw = skb->data;
84 dlen = IPCOMP_SCRATCH_SIZE;
87 err = crypto_comp_decompress(ipcd->tfm, start, plen, scratch, &dlen);
93 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
98 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
103 skb_put(skb, dlen - plen);
104 memcpy(skb->data, scratch, dlen);
107 iph->payload_len = htons(skb->len);
109 ip6_find_1stfragopt(skb, &prevhdr);
121 static int ipcomp6_output(struct sk_buff **pskb)
124 struct dst_entry *dst = (*pskb)->dst;
125 struct xfrm_state *x = dst->xfrm;
126 struct ipv6hdr *iph, *top_iph;
128 struct ipv6_comp_hdr *ipch;
129 struct ipcomp_data *ipcd = x->data;
133 u8 *start, *scratch = ipcd->scratch;
135 if ((*pskb)->ip_summed == CHECKSUM_HW) {
136 err = skb_checksum_help(pskb, 0);
141 spin_lock_bh(&x->lock);
143 err = xfrm_state_check(x, *pskb);
148 err = xfrm6_tunnel_check_size(*pskb);
152 hdr_len = sizeof(struct ipv6hdr);
153 nexthdr = IPPROTO_IPV6;
154 iph = (*pskb)->nh.ipv6h;
155 top_iph = (struct ipv6hdr *)skb_push(*pskb, sizeof(struct ipv6hdr));
156 top_iph->version = 6;
157 top_iph->priority = iph->priority;
158 top_iph->flow_lbl[0] = iph->flow_lbl[0];
159 top_iph->flow_lbl[1] = iph->flow_lbl[1];
160 top_iph->flow_lbl[2] = iph->flow_lbl[2];
161 top_iph->nexthdr = IPPROTO_IPV6; /* initial */
162 top_iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
163 top_iph->hop_limit = iph->hop_limit;
164 memcpy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr, sizeof(struct in6_addr));
165 memcpy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr, sizeof(struct in6_addr));
166 (*pskb)->nh.raw = (*pskb)->data; /* == top_iph */
167 (*pskb)->h.raw = (*pskb)->nh.raw + hdr_len;
169 hdr_len = ip6_find_1stfragopt(*pskb, &prevhdr);
173 /* check whether datagram len is larger than threshold */
174 if (((*pskb)->len - hdr_len) < ipcd->threshold) {
178 if ((skb_is_nonlinear(*pskb) || skb_cloned(*pskb)) &&
179 skb_linearize(*pskb, GFP_ATOMIC) != 0) {
185 plen = (*pskb)->len - hdr_len;
186 dlen = IPCOMP_SCRATCH_SIZE;
187 start = (*pskb)->data + hdr_len;
189 err = crypto_comp_compress(ipcd->tfm, start, plen, scratch, &dlen);
193 if ((dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
196 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
197 pskb_trim(*pskb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
199 /* insert ipcomp header and replace datagram */
200 top_iph = (*pskb)->nh.ipv6h;
202 if (x->props.mode && (x->props.flags & XFRM_STATE_NOECN))
203 IP6_ECN_clear(top_iph);
204 top_iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
205 (*pskb)->nh.raw = (*pskb)->data; /* top_iph */
206 ip6_find_1stfragopt(*pskb, &prevhdr);
207 *prevhdr = IPPROTO_COMP;
209 ipch = (struct ipv6_comp_hdr *)((unsigned char *)top_iph + hdr_len);
210 ipch->nexthdr = nexthdr;
212 ipch->cpi = htons((u16 )ntohl(x->id.spi));
214 (*pskb)->h.raw = (unsigned char*)ipch;
216 x->curlft.bytes += (*pskb)->len;
218 spin_unlock_bh(&x->lock);
220 if (((*pskb)->dst = dst_pop(dst)) == NULL) {
224 err = NET_XMIT_BYPASS;
229 spin_unlock_bh(&x->lock);
235 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
236 int type, int code, int offset, __u32 info)
239 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
240 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
241 struct xfrm_state *x;
243 if (type != ICMPV6_DEST_UNREACH || type != ICMPV6_PKT_TOOBIG)
246 spi = ntohl(ntohs(ipcomph->cpi));
247 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
251 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/"
252 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
253 spi, NIP6(iph->daddr));
257 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
259 struct xfrm_state *t = NULL;
261 t = xfrm_state_alloc();
265 t->id.proto = IPPROTO_IPV6;
266 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
267 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
268 memcpy(&t->sel, &x->sel, sizeof(t->sel));
269 t->props.family = AF_INET6;
271 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
273 t->type = xfrm_get_type(IPPROTO_IPV6, t->props.family);
277 if (t->type->init_state(t, NULL))
280 t->km.state = XFRM_STATE_VALID;
281 atomic_set(&t->tunnel_users, 1);
291 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
294 struct xfrm_state *t = NULL;
297 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
299 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
300 spi, IPPROTO_IPV6, AF_INET6);
302 t = ipcomp6_tunnel_create(x);
307 xfrm_state_insert(t);
311 atomic_inc(&t->tunnel_users);
317 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
320 crypto_free_tfm(ipcd->tfm);
322 kfree(ipcd->scratch);
325 static void ipcomp6_destroy(struct xfrm_state *x)
327 struct ipcomp_data *ipcd = x->data;
330 xfrm_state_delete_tunnel(x);
331 ipcomp6_free_data(ipcd);
334 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
337 static int ipcomp6_init_state(struct xfrm_state *x, void *args)
340 struct ipcomp_data *ipcd;
341 struct xfrm_algo_desc *calg_desc;
348 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
352 memset(ipcd, 0, sizeof(*ipcd));
353 x->props.header_len = 0;
355 x->props.header_len += sizeof(struct ipv6hdr);
357 ipcd->scratch = kmalloc(IPCOMP_SCRATCH_SIZE, GFP_KERNEL);
361 ipcd->tfm = crypto_alloc_tfm(x->calg->alg_name, 0);
366 err = ipcomp6_tunnel_attach(x);
371 calg_desc = xfrm_calg_get_byname(x->calg->alg_name);
373 ipcd->threshold = calg_desc->uinfo.comp.threshold;
380 ipcomp6_free_data(ipcd);
387 static struct xfrm_type ipcomp6_type =
389 .description = "IPCOMP6",
390 .owner = THIS_MODULE,
391 .proto = IPPROTO_COMP,
392 .init_state = ipcomp6_init_state,
393 .destructor = ipcomp6_destroy,
394 .input = ipcomp6_input,
395 .output = ipcomp6_output,
398 static struct inet6_protocol ipcomp6_protocol =
400 .handler = xfrm6_rcv,
401 .err_handler = ipcomp6_err,
402 .flags = INET6_PROTO_NOPOLICY,
405 static int __init ipcomp6_init(void)
407 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
408 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
411 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
412 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
413 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
419 static void __exit ipcomp6_fini(void)
421 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
422 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
423 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
424 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
427 module_init(ipcomp6_init);
428 module_exit(ipcomp6_fini);
429 MODULE_LICENSE("GPL");
430 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
431 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");