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/module.h>
36 #include <net/ipcomp.h>
37 #include <asm/scatterlist.h>
38 #include <asm/semaphore.h>
39 #include <linux/crypto.h>
40 #include <linux/pfkeyv2.h>
41 #include <linux/random.h>
42 #include <linux/percpu.h>
43 #include <linux/smp.h>
44 #include <linux/list.h>
45 #include <linux/vmalloc.h>
46 #include <linux/rtnetlink.h>
49 #include <net/protocol.h>
50 #include <linux/ipv6.h>
51 #include <linux/icmpv6.h>
52 #include <linux/mutex.h>
55 struct list_head list;
56 struct crypto_tfm **tfms;
60 static DEFINE_MUTEX(ipcomp6_resource_mutex);
61 static void **ipcomp6_scratches;
62 static int ipcomp6_scratch_users;
63 static LIST_HEAD(ipcomp6_tfms_list);
65 static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
69 struct ipv6_comp_hdr *ipch;
71 struct ipcomp_data *ipcd = x->data;
73 struct crypto_tfm *tfm;
76 if (skb_linearize_cow(skb))
79 skb->ip_summed = CHECKSUM_NONE;
81 /* Remove ipcomp header and decompress original payload */
83 ipch = (void *)skb->data;
84 skb->h.raw = skb->nh.raw + sizeof(*ipch);
85 __skb_pull(skb, sizeof(*ipch));
89 dlen = IPCOMP_SCRATCH_SIZE;
93 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
94 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
96 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
102 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
107 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
112 skb_put(skb, dlen - plen);
113 memcpy(skb->data, scratch, dlen);
122 static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
125 struct ipv6hdr *top_iph;
127 struct ipv6_comp_hdr *ipch;
128 struct ipcomp_data *ipcd = x->data;
131 struct crypto_tfm *tfm;
134 hdr_len = skb->h.raw - skb->data;
136 /* check whether datagram len is larger than threshold */
137 if ((skb->len - hdr_len) < ipcd->threshold) {
141 if (skb_linearize_cow(skb))
145 plen = skb->len - hdr_len;
146 dlen = IPCOMP_SCRATCH_SIZE;
150 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
151 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
153 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
154 if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
158 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
160 pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
162 /* insert ipcomp header and replace datagram */
163 top_iph = (struct ipv6hdr *)skb->data;
165 top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
167 ipch = (struct ipv6_comp_hdr *)start;
168 ipch->nexthdr = *skb->nh.raw;
170 ipch->cpi = htons((u16 )ntohl(x->id.spi));
171 *skb->nh.raw = IPPROTO_COMP;
177 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
178 int type, int code, int offset, __u32 info)
181 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
182 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
183 struct xfrm_state *x;
185 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
188 spi = htonl(ntohs(ipcomph->cpi));
189 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
193 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
194 spi, NIP6(iph->daddr));
198 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
200 struct xfrm_state *t = NULL;
202 t = xfrm_state_alloc();
206 t->id.proto = IPPROTO_IPV6;
207 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
211 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
212 memcpy(&t->sel, &x->sel, sizeof(t->sel));
213 t->props.family = AF_INET6;
215 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
217 if (xfrm_init_state(t))
220 atomic_set(&t->tunnel_users, 1);
226 t->km.state = XFRM_STATE_DEAD;
232 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
235 struct xfrm_state *t = NULL;
238 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
240 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
241 spi, IPPROTO_IPV6, AF_INET6);
243 t = ipcomp6_tunnel_create(x);
248 xfrm_state_insert(t);
252 atomic_inc(&t->tunnel_users);
258 static void ipcomp6_free_scratches(void)
263 if (--ipcomp6_scratch_users)
266 scratches = ipcomp6_scratches;
270 for_each_possible_cpu(i) {
271 void *scratch = *per_cpu_ptr(scratches, i);
276 free_percpu(scratches);
279 static void **ipcomp6_alloc_scratches(void)
284 if (ipcomp6_scratch_users++)
285 return ipcomp6_scratches;
287 scratches = alloc_percpu(void *);
291 ipcomp6_scratches = scratches;
293 for_each_possible_cpu(i) {
294 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
297 *per_cpu_ptr(scratches, i) = scratch;
303 static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
305 struct ipcomp6_tfms *pos;
308 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
309 if (pos->tfms == tfms)
318 list_del(&pos->list);
324 for_each_possible_cpu(cpu) {
325 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
326 crypto_free_tfm(tfm);
331 static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
333 struct ipcomp6_tfms *pos;
334 struct crypto_tfm **tfms;
337 /* This can be any valid CPU ID so we don't need locking. */
338 cpu = raw_smp_processor_id();
340 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
341 struct crypto_tfm *tfm;
344 tfm = *per_cpu_ptr(tfms, cpu);
346 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
352 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
357 INIT_LIST_HEAD(&pos->list);
358 list_add(&pos->list, &ipcomp6_tfms_list);
360 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
364 for_each_possible_cpu(cpu) {
365 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
368 *per_cpu_ptr(tfms, cpu) = tfm;
374 ipcomp6_free_tfms(tfms);
378 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
381 ipcomp6_free_tfms(ipcd->tfms);
382 ipcomp6_free_scratches();
385 static void ipcomp6_destroy(struct xfrm_state *x)
387 struct ipcomp_data *ipcd = x->data;
390 xfrm_state_delete_tunnel(x);
391 mutex_lock(&ipcomp6_resource_mutex);
392 ipcomp6_free_data(ipcd);
393 mutex_unlock(&ipcomp6_resource_mutex);
396 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
399 static int ipcomp6_init_state(struct xfrm_state *x)
402 struct ipcomp_data *ipcd;
403 struct xfrm_algo_desc *calg_desc;
413 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
417 x->props.header_len = 0;
419 x->props.header_len += sizeof(struct ipv6hdr);
421 mutex_lock(&ipcomp6_resource_mutex);
422 if (!ipcomp6_alloc_scratches())
425 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
428 mutex_unlock(&ipcomp6_resource_mutex);
431 err = ipcomp6_tunnel_attach(x);
436 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
438 ipcd->threshold = calg_desc->uinfo.comp.threshold;
444 mutex_lock(&ipcomp6_resource_mutex);
446 ipcomp6_free_data(ipcd);
447 mutex_unlock(&ipcomp6_resource_mutex);
453 static struct xfrm_type ipcomp6_type =
455 .description = "IPCOMP6",
456 .owner = THIS_MODULE,
457 .proto = IPPROTO_COMP,
458 .init_state = ipcomp6_init_state,
459 .destructor = ipcomp6_destroy,
460 .input = ipcomp6_input,
461 .output = ipcomp6_output,
464 static struct inet6_protocol ipcomp6_protocol =
466 .handler = xfrm6_rcv,
467 .err_handler = ipcomp6_err,
468 .flags = INET6_PROTO_NOPOLICY,
471 static int __init ipcomp6_init(void)
473 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
474 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
477 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
478 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
479 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
485 static void __exit ipcomp6_fini(void)
487 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
488 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
489 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
490 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
493 module_init(ipcomp6_init);
494 module_exit(ipcomp6_fini);
495 MODULE_LICENSE("GPL");
496 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
497 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");