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>");