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>
37 #include <net/ipcomp.h>
38 #include <asm/scatterlist.h>
39 #include <linux/crypto.h>
40 #include <linux/pfkeyv2.h>
41 #include <linux/random.h>
44 #include <linux/ipv6.h>
45 #include <linux/icmpv6.h>
47 static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
51 int hdr_len = skb->h.raw - skb->nh.raw;
52 unsigned char *tmp_hdr = NULL;
55 struct ipcomp_data *ipcd = x->data;
56 u8 *start, *scratch = ipcd->scratch;
58 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
59 skb_linearize(skb, GFP_ATOMIC) != 0) {
64 skb->ip_summed = CHECKSUM_NONE;
66 /* Remove ipcomp header and decompress original payload */
68 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
71 memcpy(tmp_hdr, iph, hdr_len);
72 nexthdr = *(u8 *)skb->data;
73 skb_pull(skb, sizeof(struct ipv6_comp_hdr));
74 skb->nh.raw += sizeof(struct ipv6_comp_hdr);
75 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
77 iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
78 skb->h.raw = skb->data;
82 dlen = IPCOMP_SCRATCH_SIZE;
85 err = crypto_comp_decompress(ipcd->tfm, start, plen, scratch, &dlen);
91 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
96 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
101 skb_put(skb, dlen - plen);
102 memcpy(skb->data, scratch, dlen);
105 iph->payload_len = htons(skb->len);
117 static int ipcomp6_output(struct sk_buff **pskb)
120 struct dst_entry *dst = (*pskb)->dst;
121 struct xfrm_state *x = dst->xfrm;
122 struct ipv6hdr *top_iph;
124 struct ipv6_comp_hdr *ipch;
125 struct ipcomp_data *ipcd = x->data;
127 u8 *start, *scratch = ipcd->scratch;
129 hdr_len = (*pskb)->h.raw - (*pskb)->data;
131 /* check whether datagram len is larger than threshold */
132 if (((*pskb)->len - hdr_len) < ipcd->threshold) {
136 if ((skb_is_nonlinear(*pskb) || skb_cloned(*pskb)) &&
137 skb_linearize(*pskb, GFP_ATOMIC) != 0) {
143 plen = (*pskb)->len - hdr_len;
144 dlen = IPCOMP_SCRATCH_SIZE;
145 start = (*pskb)->h.raw;
147 err = crypto_comp_compress(ipcd->tfm, start, plen, scratch, &dlen);
151 if ((dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
154 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
155 pskb_trim(*pskb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
157 /* insert ipcomp header and replace datagram */
158 top_iph = (struct ipv6hdr *)(*pskb)->data;
160 top_iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
162 ipch = (struct ipv6_comp_hdr *)start;
163 ipch->nexthdr = *(*pskb)->nh.raw;
165 ipch->cpi = htons((u16 )ntohl(x->id.spi));
166 *(*pskb)->nh.raw = IPPROTO_COMP;
175 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
176 int type, int code, int offset, __u32 info)
179 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
180 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
181 struct xfrm_state *x;
183 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
186 spi = ntohl(ntohs(ipcomph->cpi));
187 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
191 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/"
192 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
193 spi, NIP6(iph->daddr));
197 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
199 struct xfrm_state *t = NULL;
201 t = xfrm_state_alloc();
205 t->id.proto = IPPROTO_IPV6;
206 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
207 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
208 memcpy(&t->sel, &x->sel, sizeof(t->sel));
209 t->props.family = AF_INET6;
211 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
213 t->type = xfrm_get_type(IPPROTO_IPV6, t->props.family);
217 if (t->type->init_state(t, NULL))
220 t->km.state = XFRM_STATE_VALID;
221 atomic_set(&t->tunnel_users, 1);
231 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
234 struct xfrm_state *t = NULL;
237 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
239 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
240 spi, IPPROTO_IPV6, AF_INET6);
242 t = ipcomp6_tunnel_create(x);
247 xfrm_state_insert(t);
251 atomic_inc(&t->tunnel_users);
257 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
260 crypto_free_tfm(ipcd->tfm);
262 kfree(ipcd->scratch);
265 static void ipcomp6_destroy(struct xfrm_state *x)
267 struct ipcomp_data *ipcd = x->data;
270 xfrm_state_delete_tunnel(x);
271 ipcomp6_free_data(ipcd);
274 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
277 static int ipcomp6_init_state(struct xfrm_state *x, void *args)
280 struct ipcomp_data *ipcd;
281 struct xfrm_algo_desc *calg_desc;
288 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
292 memset(ipcd, 0, sizeof(*ipcd));
293 x->props.header_len = 0;
295 x->props.header_len += sizeof(struct ipv6hdr);
297 ipcd->scratch = kmalloc(IPCOMP_SCRATCH_SIZE, GFP_KERNEL);
301 ipcd->tfm = crypto_alloc_tfm(x->calg->alg_name, 0);
306 err = ipcomp6_tunnel_attach(x);
311 calg_desc = xfrm_calg_get_byname(x->calg->alg_name);
313 ipcd->threshold = calg_desc->uinfo.comp.threshold;
320 ipcomp6_free_data(ipcd);
327 static struct xfrm_type ipcomp6_type =
329 .description = "IPCOMP6",
330 .owner = THIS_MODULE,
331 .proto = IPPROTO_COMP,
332 .init_state = ipcomp6_init_state,
333 .destructor = ipcomp6_destroy,
334 .input = ipcomp6_input,
335 .output = ipcomp6_output,
338 static struct inet6_protocol ipcomp6_protocol =
340 .handler = xfrm6_rcv,
341 .err_handler = ipcomp6_err,
342 .flags = INET6_PROTO_NOPOLICY,
345 static int __init ipcomp6_init(void)
347 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
348 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
351 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
352 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
353 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
359 static void __exit ipcomp6_fini(void)
361 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
362 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
363 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
364 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
367 module_init(ipcomp6_init);
368 module_exit(ipcomp6_fini);
369 MODULE_LICENSE("GPL");
370 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
371 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");