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>");