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 <asm/semaphore.h>
40 #include <linux/crypto.h>
41 #include <linux/pfkeyv2.h>
42 #include <linux/random.h>
43 #include <linux/percpu.h>
44 #include <linux/smp.h>
45 #include <linux/list.h>
46 #include <linux/vmalloc.h>
47 #include <linux/rtnetlink.h>
50 #include <linux/ipv6.h>
51 #include <linux/icmpv6.h>
54 struct list_head list;
55 struct crypto_tfm **tfms;
59 static DECLARE_MUTEX(ipcomp6_resource_sem);
60 static void **ipcomp6_scratches;
61 static int ipcomp6_scratch_users;
62 static LIST_HEAD(ipcomp6_tfms_list);
64 static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
68 int hdr_len = skb->h.raw - skb->nh.raw;
69 unsigned char *tmp_hdr = NULL;
72 struct ipcomp_data *ipcd = x->data;
74 struct crypto_tfm *tfm;
77 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
78 skb_linearize(skb, GFP_ATOMIC) != 0) {
83 skb->ip_summed = CHECKSUM_NONE;
85 /* Remove ipcomp header and decompress original payload */
87 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
90 memcpy(tmp_hdr, iph, hdr_len);
91 nexthdr = *(u8 *)skb->data;
92 skb_pull(skb, sizeof(struct ipv6_comp_hdr));
93 skb->nh.raw += sizeof(struct ipv6_comp_hdr);
94 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
96 iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
97 skb->h.raw = skb->data;
101 dlen = IPCOMP_SCRATCH_SIZE;
105 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
106 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
108 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
114 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
119 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
124 skb_put(skb, dlen - plen);
125 memcpy(skb->data, scratch, dlen);
128 iph->payload_len = htons(skb->len);
142 static int ipcomp6_output(struct sk_buff *skb)
145 struct dst_entry *dst = skb->dst;
146 struct xfrm_state *x = dst->xfrm;
147 struct ipv6hdr *top_iph;
149 struct ipv6_comp_hdr *ipch;
150 struct ipcomp_data *ipcd = x->data;
153 struct crypto_tfm *tfm;
156 hdr_len = skb->h.raw - skb->data;
158 /* check whether datagram len is larger than threshold */
159 if ((skb->len - hdr_len) < ipcd->threshold) {
163 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
164 skb_linearize(skb, GFP_ATOMIC) != 0) {
170 plen = skb->len - hdr_len;
171 dlen = IPCOMP_SCRATCH_SIZE;
175 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
176 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
178 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
183 if ((dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
187 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
189 pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
191 /* insert ipcomp header and replace datagram */
192 top_iph = (struct ipv6hdr *)skb->data;
194 top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
196 ipch = (struct ipv6_comp_hdr *)start;
197 ipch->nexthdr = *skb->nh.raw;
199 ipch->cpi = htons((u16 )ntohl(x->id.spi));
200 *skb->nh.raw = IPPROTO_COMP;
209 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
210 int type, int code, int offset, __u32 info)
213 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
214 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
215 struct xfrm_state *x;
217 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
220 spi = ntohl(ntohs(ipcomph->cpi));
221 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
225 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/"
226 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
227 spi, NIP6(iph->daddr));
231 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
233 struct xfrm_state *t = NULL;
235 t = xfrm_state_alloc();
239 t->id.proto = IPPROTO_IPV6;
240 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
241 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
242 memcpy(&t->sel, &x->sel, sizeof(t->sel));
243 t->props.family = AF_INET6;
245 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
247 t->type = xfrm_get_type(IPPROTO_IPV6, t->props.family);
251 if (t->type->init_state(t, NULL))
254 t->km.state = XFRM_STATE_VALID;
255 atomic_set(&t->tunnel_users, 1);
265 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
268 struct xfrm_state *t = NULL;
271 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
273 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
274 spi, IPPROTO_IPV6, AF_INET6);
276 t = ipcomp6_tunnel_create(x);
281 xfrm_state_insert(t);
285 atomic_inc(&t->tunnel_users);
291 static void ipcomp6_free_scratches(void)
296 if (--ipcomp6_scratch_users)
299 scratches = ipcomp6_scratches;
304 void *scratch = *per_cpu_ptr(scratches, i);
309 free_percpu(scratches);
312 static void **ipcomp6_alloc_scratches(void)
317 if (ipcomp6_scratch_users++)
318 return ipcomp6_scratches;
320 scratches = alloc_percpu(void *);
324 ipcomp6_scratches = scratches;
327 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
330 *per_cpu_ptr(scratches, i) = scratch;
336 static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
338 struct ipcomp6_tfms *pos;
341 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
342 if (pos->tfms == tfms)
351 list_del(&pos->list);
358 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
360 crypto_free_tfm(tfm);
365 static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
367 struct ipcomp6_tfms *pos;
368 struct crypto_tfm **tfms;
371 /* This can be any valid CPU ID so we don't need locking. */
372 cpu = smp_processor_id();
374 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
375 struct crypto_tfm *tfm;
378 tfm = *per_cpu_ptr(tfms, cpu);
380 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
386 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
391 INIT_LIST_HEAD(&pos->list);
392 list_add(&pos->list, &ipcomp6_tfms_list);
394 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
399 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
402 *per_cpu_ptr(tfms, cpu) = tfm;
408 ipcomp6_free_tfms(tfms);
412 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
415 ipcomp6_free_tfms(ipcd->tfms);
416 ipcomp6_free_scratches();
419 static void ipcomp6_destroy(struct xfrm_state *x)
421 struct ipcomp_data *ipcd = x->data;
424 xfrm_state_delete_tunnel(x);
425 down(&ipcomp6_resource_sem);
426 ipcomp6_free_data(ipcd);
427 up(&ipcomp6_resource_sem);
430 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
433 static int ipcomp6_init_state(struct xfrm_state *x, void *args)
436 struct ipcomp_data *ipcd;
437 struct xfrm_algo_desc *calg_desc;
447 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
451 memset(ipcd, 0, sizeof(*ipcd));
452 x->props.header_len = 0;
454 x->props.header_len += sizeof(struct ipv6hdr);
456 down(&ipcomp6_resource_sem);
457 if (!ipcomp6_alloc_scratches())
460 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
463 up(&ipcomp6_resource_sem);
466 err = ipcomp6_tunnel_attach(x);
471 calg_desc = xfrm_calg_get_byname(x->calg->alg_name);
473 ipcd->threshold = calg_desc->uinfo.comp.threshold;
479 down(&ipcomp6_resource_sem);
481 ipcomp6_free_data(ipcd);
482 up(&ipcomp6_resource_sem);
488 static struct xfrm_type ipcomp6_type =
490 .description = "IPCOMP6",
491 .owner = THIS_MODULE,
492 .proto = IPPROTO_COMP,
493 .init_state = ipcomp6_init_state,
494 .destructor = ipcomp6_destroy,
495 .input = ipcomp6_input,
496 .output = ipcomp6_output,
499 static struct inet6_protocol ipcomp6_protocol =
501 .handler = xfrm6_rcv,
502 .err_handler = ipcomp6_err,
503 .flags = INET6_PROTO_NOPOLICY,
506 static int __init ipcomp6_init(void)
508 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
509 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
512 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
513 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
514 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
520 static void __exit ipcomp6_fini(void)
522 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
523 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
524 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
525 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
528 module_init(ipcomp6_init);
529 module_exit(ipcomp6_fini);
530 MODULE_LICENSE("GPL");
531 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
532 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");