2 * IP Payload Compression Protocol (IPComp) - RFC3173.
4 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
5 * Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.au>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
13 * - Tunable compression parameters.
14 * - Compression stats.
15 * - Adaptive compression.
18 #include <linux/crypto.h>
19 #include <linux/err.h>
20 #include <linux/list.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/percpu.h>
24 #include <linux/rtnetlink.h>
25 #include <linux/smp.h>
26 #include <linux/vmalloc.h>
28 #include <net/ipcomp.h>
32 struct list_head list;
33 struct crypto_comp **tfms;
37 static DEFINE_MUTEX(ipcomp_resource_mutex);
38 static void **ipcomp_scratches;
39 static int ipcomp_scratch_users;
40 static LIST_HEAD(ipcomp_tfms_list);
42 static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
44 struct ipcomp_data *ipcd = x->data;
45 const int plen = skb->len;
46 int dlen = IPCOMP_SCRATCH_SIZE;
47 const u8 *start = skb->data;
48 const int cpu = get_cpu();
49 u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
50 struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
51 int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
56 if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
61 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
65 skb->truesize += dlen - plen;
66 __skb_put(skb, dlen - plen);
67 skb_copy_to_linear_data(skb, scratch, dlen);
73 int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
77 struct ip_comp_hdr *ipch;
79 if (skb_linearize_cow(skb))
82 skb->ip_summed = CHECKSUM_NONE;
84 /* Remove ipcomp header and decompress original payload */
85 ipch = (void *)skb->data;
86 nexthdr = ipch->nexthdr;
88 skb->transport_header = skb->network_header + sizeof(*ipch);
89 __skb_pull(skb, sizeof(*ipch));
90 err = ipcomp_decompress(x, skb);
99 EXPORT_SYMBOL_GPL(ipcomp_input);
101 static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
103 struct ipcomp_data *ipcd = x->data;
104 const int plen = skb->len;
105 int dlen = IPCOMP_SCRATCH_SIZE;
106 u8 *start = skb->data;
107 const int cpu = get_cpu();
108 u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
109 struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
113 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
118 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
123 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
126 pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
134 int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
137 struct ip_comp_hdr *ipch;
138 struct ipcomp_data *ipcd = x->data;
140 if (skb->len < ipcd->threshold) {
141 /* Don't bother compressing */
145 if (skb_linearize_cow(skb))
148 err = ipcomp_compress(x, skb);
154 /* Install ipcomp header, convert into ipcomp datagram. */
155 ipch = ip_comp_hdr(skb);
156 ipch->nexthdr = *skb_mac_header(skb);
158 ipch->cpi = htons((u16 )ntohl(x->id.spi));
159 *skb_mac_header(skb) = IPPROTO_COMP;
161 skb_push(skb, -skb_network_offset(skb));
164 EXPORT_SYMBOL_GPL(ipcomp_output);
166 static void ipcomp_free_scratches(void)
171 if (--ipcomp_scratch_users)
174 scratches = ipcomp_scratches;
178 for_each_possible_cpu(i)
179 vfree(*per_cpu_ptr(scratches, i));
181 free_percpu(scratches);
184 static void **ipcomp_alloc_scratches(void)
189 if (ipcomp_scratch_users++)
190 return ipcomp_scratches;
192 scratches = alloc_percpu(void *);
196 ipcomp_scratches = scratches;
198 for_each_possible_cpu(i) {
199 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
202 *per_cpu_ptr(scratches, i) = scratch;
208 static void ipcomp_free_tfms(struct crypto_comp **tfms)
210 struct ipcomp_tfms *pos;
213 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
214 if (pos->tfms == tfms)
223 list_del(&pos->list);
229 for_each_possible_cpu(cpu) {
230 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
231 crypto_free_comp(tfm);
236 static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name)
238 struct ipcomp_tfms *pos;
239 struct crypto_comp **tfms;
242 /* This can be any valid CPU ID so we don't need locking. */
243 cpu = raw_smp_processor_id();
245 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
246 struct crypto_comp *tfm;
249 tfm = *per_cpu_ptr(tfms, cpu);
251 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
257 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
262 INIT_LIST_HEAD(&pos->list);
263 list_add(&pos->list, &ipcomp_tfms_list);
265 pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
269 for_each_possible_cpu(cpu) {
270 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
274 *per_cpu_ptr(tfms, cpu) = tfm;
280 ipcomp_free_tfms(tfms);
284 static void ipcomp_free_data(struct ipcomp_data *ipcd)
287 ipcomp_free_tfms(ipcd->tfms);
288 ipcomp_free_scratches();
291 void ipcomp_destroy(struct xfrm_state *x)
293 struct ipcomp_data *ipcd = x->data;
296 xfrm_state_delete_tunnel(x);
297 mutex_lock(&ipcomp_resource_mutex);
298 ipcomp_free_data(ipcd);
299 mutex_unlock(&ipcomp_resource_mutex);
302 EXPORT_SYMBOL_GPL(ipcomp_destroy);
304 int ipcomp_init_state(struct xfrm_state *x)
307 struct ipcomp_data *ipcd;
308 struct xfrm_algo_desc *calg_desc;
318 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
322 mutex_lock(&ipcomp_resource_mutex);
323 if (!ipcomp_alloc_scratches())
326 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
329 mutex_unlock(&ipcomp_resource_mutex);
331 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
333 ipcd->threshold = calg_desc->uinfo.comp.threshold;
340 ipcomp_free_data(ipcd);
341 mutex_unlock(&ipcomp_resource_mutex);
345 EXPORT_SYMBOL_GPL(ipcomp_init_state);
347 MODULE_LICENSE("GPL");
348 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
349 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");