1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * IP Payload Compression Protocol (IPComp) - RFC3173.
5 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
6 * Copyright (c) 2003-2008 Herbert Xu <herbert@gondor.apana.org.au>
9 * - Tunable compression parameters.
10 * - Compression stats.
11 * - Adaptive compression.
14 #include <linux/crypto.h>
15 #include <linux/err.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/percpu.h>
20 #include <linux/slab.h>
21 #include <linux/smp.h>
22 #include <linux/vmalloc.h>
24 #include <net/ipcomp.h>
28 struct list_head list;
29 struct crypto_comp * __percpu *tfms;
33 static DEFINE_MUTEX(ipcomp_resource_mutex);
34 static void * __percpu *ipcomp_scratches;
35 static int ipcomp_scratch_users;
36 static LIST_HEAD(ipcomp_tfms_list);
38 static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
40 struct ipcomp_data *ipcd = x->data;
41 const int plen = skb->len;
42 int dlen = IPCOMP_SCRATCH_SIZE;
43 const u8 *start = skb->data;
44 const int cpu = get_cpu();
45 u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
46 struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
47 int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
53 if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
59 if (len > skb_tailroom(skb))
60 len = skb_tailroom(skb);
65 skb_copy_to_linear_data(skb, scratch, len);
67 while ((scratch += len, dlen -= len) > 0) {
72 if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
75 frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
76 page = alloc_page(GFP_ATOMIC);
82 __skb_frag_set_page(frag, page);
88 skb_frag_off_set(frag, 0);
89 skb_frag_size_set(frag, len);
90 memcpy(skb_frag_address(frag), scratch, len);
96 skb_shinfo(skb)->nr_frags++;
106 int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
110 struct ip_comp_hdr *ipch;
112 if (skb_linearize_cow(skb))
115 skb->ip_summed = CHECKSUM_NONE;
117 /* Remove ipcomp header and decompress original payload */
118 ipch = (void *)skb->data;
119 nexthdr = ipch->nexthdr;
121 skb->transport_header = skb->network_header + sizeof(*ipch);
122 __skb_pull(skb, sizeof(*ipch));
123 err = ipcomp_decompress(x, skb);
132 EXPORT_SYMBOL_GPL(ipcomp_input);
134 static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
136 struct ipcomp_data *ipcd = x->data;
137 const int plen = skb->len;
138 int dlen = IPCOMP_SCRATCH_SIZE;
139 u8 *start = skb->data;
140 struct crypto_comp *tfm;
145 scratch = *this_cpu_ptr(ipcomp_scratches);
146 tfm = *this_cpu_ptr(ipcd->tfms);
147 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
151 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
156 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
159 pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
167 int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
170 struct ip_comp_hdr *ipch;
171 struct ipcomp_data *ipcd = x->data;
173 if (skb->len < ipcd->threshold) {
174 /* Don't bother compressing */
178 if (skb_linearize_cow(skb))
181 err = ipcomp_compress(x, skb);
187 /* Install ipcomp header, convert into ipcomp datagram. */
188 ipch = ip_comp_hdr(skb);
189 ipch->nexthdr = *skb_mac_header(skb);
191 ipch->cpi = htons((u16 )ntohl(x->id.spi));
192 *skb_mac_header(skb) = IPPROTO_COMP;
194 skb_push(skb, -skb_network_offset(skb));
197 EXPORT_SYMBOL_GPL(ipcomp_output);
199 static void ipcomp_free_scratches(void)
202 void * __percpu *scratches;
204 if (--ipcomp_scratch_users)
207 scratches = ipcomp_scratches;
211 for_each_possible_cpu(i)
212 vfree(*per_cpu_ptr(scratches, i));
214 free_percpu(scratches);
215 ipcomp_scratches = NULL;
218 static void * __percpu *ipcomp_alloc_scratches(void)
220 void * __percpu *scratches;
223 if (ipcomp_scratch_users++)
224 return ipcomp_scratches;
226 scratches = alloc_percpu(void *);
230 ipcomp_scratches = scratches;
232 for_each_possible_cpu(i) {
235 scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
238 *per_cpu_ptr(scratches, i) = scratch;
244 static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms)
246 struct ipcomp_tfms *pos;
249 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
250 if (pos->tfms == tfms)
259 list_del(&pos->list);
265 for_each_possible_cpu(cpu) {
266 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
267 crypto_free_comp(tfm);
272 static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
274 struct ipcomp_tfms *pos;
275 struct crypto_comp * __percpu *tfms;
279 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
280 struct crypto_comp *tfm;
282 /* This can be any valid CPU ID so we don't need locking. */
283 tfm = this_cpu_read(*pos->tfms);
285 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
291 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
296 INIT_LIST_HEAD(&pos->list);
297 list_add(&pos->list, &ipcomp_tfms_list);
299 pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
303 for_each_possible_cpu(cpu) {
304 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
308 *per_cpu_ptr(tfms, cpu) = tfm;
314 ipcomp_free_tfms(tfms);
318 static void ipcomp_free_data(struct ipcomp_data *ipcd)
321 ipcomp_free_tfms(ipcd->tfms);
322 ipcomp_free_scratches();
325 void ipcomp_destroy(struct xfrm_state *x)
327 struct ipcomp_data *ipcd = x->data;
330 xfrm_state_delete_tunnel(x);
331 mutex_lock(&ipcomp_resource_mutex);
332 ipcomp_free_data(ipcd);
333 mutex_unlock(&ipcomp_resource_mutex);
336 EXPORT_SYMBOL_GPL(ipcomp_destroy);
338 int ipcomp_init_state(struct xfrm_state *x)
341 struct ipcomp_data *ipcd;
342 struct xfrm_algo_desc *calg_desc;
352 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
356 mutex_lock(&ipcomp_resource_mutex);
357 if (!ipcomp_alloc_scratches())
360 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
363 mutex_unlock(&ipcomp_resource_mutex);
365 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
367 ipcd->threshold = calg_desc->uinfo.comp.threshold;
374 ipcomp_free_data(ipcd);
375 mutex_unlock(&ipcomp_resource_mutex);
379 EXPORT_SYMBOL_GPL(ipcomp_init_state);
381 MODULE_LICENSE("GPL");
382 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
383 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");