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1/*
2 * Checksum updating actions
3 *
4 * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <linux/types.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/spinlock.h>
18
19#include <linux/netlink.h>
20#include <net/netlink.h>
21#include <linux/rtnetlink.h>
22
23#include <linux/skbuff.h>
24
25#include <net/ip.h>
26#include <net/ipv6.h>
27#include <net/icmp.h>
28#include <linux/icmpv6.h>
29#include <linux/igmp.h>
30#include <net/tcp.h>
31#include <net/udp.h>
32#include <net/ip6_checksum.h>
33
34#include <net/act_api.h>
35
36#include <linux/tc_act/tc_csum.h>
37#include <net/tc_act/tc_csum.h>
38
39#define CSUM_TAB_MASK 15
40
41static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
42 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
43};
44
45static int csum_net_id;
46
47static int tcf_csum_init(struct net *net, struct nlattr *nla,
48 struct nlattr *est, struct tc_action *a, int ovr,
49 int bind)
50{
51 struct tc_action_net *tn = net_generic(net, csum_net_id);
52 struct nlattr *tb[TCA_CSUM_MAX + 1];
53 struct tc_csum *parm;
54 struct tcf_csum *p;
55 int ret = 0, err;
56
57 if (nla == NULL)
58 return -EINVAL;
59
60 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
61 if (err < 0)
62 return err;
63
64 if (tb[TCA_CSUM_PARMS] == NULL)
65 return -EINVAL;
66 parm = nla_data(tb[TCA_CSUM_PARMS]);
67
68 if (!tcf_hash_check(tn, parm->index, a, bind)) {
69 ret = tcf_hash_create(tn, parm->index, est, a,
70 sizeof(*p), bind, false);
71 if (ret)
72 return ret;
73 ret = ACT_P_CREATED;
74 } else {
75 if (bind)/* dont override defaults */
76 return 0;
77 tcf_hash_release(a, bind);
78 if (!ovr)
79 return -EEXIST;
80 }
81
82 p = to_tcf_csum(a);
83 spin_lock_bh(&p->tcf_lock);
84 p->tcf_action = parm->action;
85 p->update_flags = parm->update_flags;
86 spin_unlock_bh(&p->tcf_lock);
87
88 if (ret == ACT_P_CREATED)
89 tcf_hash_insert(tn, a);
90
91 return ret;
92}
93
94/**
95 * tcf_csum_skb_nextlayer - Get next layer pointer
96 * @skb: sk_buff to use
97 * @ihl: previous summed headers length
98 * @ipl: complete packet length
99 * @jhl: next header length
100 *
101 * Check the expected next layer availability in the specified sk_buff.
102 * Return the next layer pointer if pass, NULL otherwise.
103 */
104static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
105 unsigned int ihl, unsigned int ipl,
106 unsigned int jhl)
107{
108 int ntkoff = skb_network_offset(skb);
109 int hl = ihl + jhl;
110
111 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
112 skb_try_make_writable(skb, hl + ntkoff))
113 return NULL;
114 else
115 return (void *)(skb_network_header(skb) + ihl);
116}
117
118static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
119 unsigned int ihl, unsigned int ipl)
120{
121 struct icmphdr *icmph;
122
123 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
124 if (icmph == NULL)
125 return 0;
126
127 icmph->checksum = 0;
128 skb->csum = csum_partial(icmph, ipl - ihl, 0);
129 icmph->checksum = csum_fold(skb->csum);
130
131 skb->ip_summed = CHECKSUM_NONE;
132
133 return 1;
134}
135
136static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
137 unsigned int ihl, unsigned int ipl)
138{
139 struct igmphdr *igmph;
140
141 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
142 if (igmph == NULL)
143 return 0;
144
145 igmph->csum = 0;
146 skb->csum = csum_partial(igmph, ipl - ihl, 0);
147 igmph->csum = csum_fold(skb->csum);
148
149 skb->ip_summed = CHECKSUM_NONE;
150
151 return 1;
152}
153
154static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
155 unsigned int ihl, unsigned int ipl)
156{
157 struct icmp6hdr *icmp6h;
158 const struct ipv6hdr *ip6h;
159
160 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
161 if (icmp6h == NULL)
162 return 0;
163
164 ip6h = ipv6_hdr(skb);
165 icmp6h->icmp6_cksum = 0;
166 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
167 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
168 ipl - ihl, IPPROTO_ICMPV6,
169 skb->csum);
170
171 skb->ip_summed = CHECKSUM_NONE;
172
173 return 1;
174}
175
176static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
177 unsigned int ihl, unsigned int ipl)
178{
179 struct tcphdr *tcph;
180 const struct iphdr *iph;
181
182 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
183 if (tcph == NULL)
184 return 0;
185
186 iph = ip_hdr(skb);
187 tcph->check = 0;
188 skb->csum = csum_partial(tcph, ipl - ihl, 0);
189 tcph->check = tcp_v4_check(ipl - ihl,
190 iph->saddr, iph->daddr, skb->csum);
191
192 skb->ip_summed = CHECKSUM_NONE;
193
194 return 1;
195}
196
197static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
198 unsigned int ihl, unsigned int ipl)
199{
200 struct tcphdr *tcph;
201 const struct ipv6hdr *ip6h;
202
203 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
204 if (tcph == NULL)
205 return 0;
206
207 ip6h = ipv6_hdr(skb);
208 tcph->check = 0;
209 skb->csum = csum_partial(tcph, ipl - ihl, 0);
210 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
211 ipl - ihl, IPPROTO_TCP,
212 skb->csum);
213
214 skb->ip_summed = CHECKSUM_NONE;
215
216 return 1;
217}
218
219static int tcf_csum_ipv4_udp(struct sk_buff *skb,
220 unsigned int ihl, unsigned int ipl, int udplite)
221{
222 struct udphdr *udph;
223 const struct iphdr *iph;
224 u16 ul;
225
226 /*
227 * Support both UDP and UDPLITE checksum algorithms, Don't use
228 * udph->len to get the real length without any protocol check,
229 * UDPLITE uses udph->len for another thing,
230 * Use iph->tot_len, or just ipl.
231 */
232
233 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
234 if (udph == NULL)
235 return 0;
236
237 iph = ip_hdr(skb);
238 ul = ntohs(udph->len);
239
240 if (udplite || udph->check) {
241
242 udph->check = 0;
243
244 if (udplite) {
245 if (ul == 0)
246 skb->csum = csum_partial(udph, ipl - ihl, 0);
247 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
248 skb->csum = csum_partial(udph, ul, 0);
249 else
250 goto ignore_obscure_skb;
251 } else {
252 if (ul != ipl - ihl)
253 goto ignore_obscure_skb;
254
255 skb->csum = csum_partial(udph, ul, 0);
256 }
257
258 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
259 ul, iph->protocol,
260 skb->csum);
261
262 if (!udph->check)
263 udph->check = CSUM_MANGLED_0;
264 }
265
266 skb->ip_summed = CHECKSUM_NONE;
267
268ignore_obscure_skb:
269 return 1;
270}
271
272static int tcf_csum_ipv6_udp(struct sk_buff *skb,
273 unsigned int ihl, unsigned int ipl, int udplite)
274{
275 struct udphdr *udph;
276 const struct ipv6hdr *ip6h;
277 u16 ul;
278
279 /*
280 * Support both UDP and UDPLITE checksum algorithms, Don't use
281 * udph->len to get the real length without any protocol check,
282 * UDPLITE uses udph->len for another thing,
283 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
284 */
285
286 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
287 if (udph == NULL)
288 return 0;
289
290 ip6h = ipv6_hdr(skb);
291 ul = ntohs(udph->len);
292
293 udph->check = 0;
294
295 if (udplite) {
296 if (ul == 0)
297 skb->csum = csum_partial(udph, ipl - ihl, 0);
298
299 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
300 skb->csum = csum_partial(udph, ul, 0);
301
302 else
303 goto ignore_obscure_skb;
304 } else {
305 if (ul != ipl - ihl)
306 goto ignore_obscure_skb;
307
308 skb->csum = csum_partial(udph, ul, 0);
309 }
310
311 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
312 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
313 skb->csum);
314
315 if (!udph->check)
316 udph->check = CSUM_MANGLED_0;
317
318 skb->ip_summed = CHECKSUM_NONE;
319
320ignore_obscure_skb:
321 return 1;
322}
323
324static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
325{
326 const struct iphdr *iph;
327 int ntkoff;
328
329 ntkoff = skb_network_offset(skb);
330
331 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
332 goto fail;
333
334 iph = ip_hdr(skb);
335
336 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
337 case IPPROTO_ICMP:
338 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
339 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
340 ntohs(iph->tot_len)))
341 goto fail;
342 break;
343 case IPPROTO_IGMP:
344 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
345 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
346 ntohs(iph->tot_len)))
347 goto fail;
348 break;
349 case IPPROTO_TCP:
350 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
351 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
352 ntohs(iph->tot_len)))
353 goto fail;
354 break;
355 case IPPROTO_UDP:
356 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
357 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
358 ntohs(iph->tot_len), 0))
359 goto fail;
360 break;
361 case IPPROTO_UDPLITE:
362 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
363 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
364 ntohs(iph->tot_len), 1))
365 goto fail;
366 break;
367 }
368
369 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
370 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
371 goto fail;
372
373 ip_send_check(ip_hdr(skb));
374 }
375
376 return 1;
377
378fail:
379 return 0;
380}
381
382static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
383 unsigned int ixhl, unsigned int *pl)
384{
385 int off, len, optlen;
386 unsigned char *xh = (void *)ip6xh;
387
388 off = sizeof(*ip6xh);
389 len = ixhl - off;
390
391 while (len > 1) {
392 switch (xh[off]) {
393 case IPV6_TLV_PAD1:
394 optlen = 1;
395 break;
396 case IPV6_TLV_JUMBO:
397 optlen = xh[off + 1] + 2;
398 if (optlen != 6 || len < 6 || (off & 3) != 2)
399 /* wrong jumbo option length/alignment */
400 return 0;
401 *pl = ntohl(*(__be32 *)(xh + off + 2));
402 goto done;
403 default:
404 optlen = xh[off + 1] + 2;
405 if (optlen > len)
406 /* ignore obscure options */
407 goto done;
408 break;
409 }
410 off += optlen;
411 len -= optlen;
412 }
413
414done:
415 return 1;
416}
417
418static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
419{
420 struct ipv6hdr *ip6h;
421 struct ipv6_opt_hdr *ip6xh;
422 unsigned int hl, ixhl;
423 unsigned int pl;
424 int ntkoff;
425 u8 nexthdr;
426
427 ntkoff = skb_network_offset(skb);
428
429 hl = sizeof(*ip6h);
430
431 if (!pskb_may_pull(skb, hl + ntkoff))
432 goto fail;
433
434 ip6h = ipv6_hdr(skb);
435
436 pl = ntohs(ip6h->payload_len);
437 nexthdr = ip6h->nexthdr;
438
439 do {
440 switch (nexthdr) {
441 case NEXTHDR_FRAGMENT:
442 goto ignore_skb;
443 case NEXTHDR_ROUTING:
444 case NEXTHDR_HOP:
445 case NEXTHDR_DEST:
446 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
447 goto fail;
448 ip6xh = (void *)(skb_network_header(skb) + hl);
449 ixhl = ipv6_optlen(ip6xh);
450 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
451 goto fail;
452 ip6xh = (void *)(skb_network_header(skb) + hl);
453 if ((nexthdr == NEXTHDR_HOP) &&
454 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
455 goto fail;
456 nexthdr = ip6xh->nexthdr;
457 hl += ixhl;
458 break;
459 case IPPROTO_ICMPV6:
460 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
461 if (!tcf_csum_ipv6_icmp(skb,
462 hl, pl + sizeof(*ip6h)))
463 goto fail;
464 goto done;
465 case IPPROTO_TCP:
466 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
467 if (!tcf_csum_ipv6_tcp(skb,
468 hl, pl + sizeof(*ip6h)))
469 goto fail;
470 goto done;
471 case IPPROTO_UDP:
472 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
473 if (!tcf_csum_ipv6_udp(skb, hl,
474 pl + sizeof(*ip6h), 0))
475 goto fail;
476 goto done;
477 case IPPROTO_UDPLITE:
478 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
479 if (!tcf_csum_ipv6_udp(skb, hl,
480 pl + sizeof(*ip6h), 1))
481 goto fail;
482 goto done;
483 default:
484 goto ignore_skb;
485 }
486 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
487
488done:
489ignore_skb:
490 return 1;
491
492fail:
493 return 0;
494}
495
496static int tcf_csum(struct sk_buff *skb,
497 const struct tc_action *a, struct tcf_result *res)
498{
499 struct tcf_csum *p = a->priv;
500 int action;
501 u32 update_flags;
502
503 spin_lock(&p->tcf_lock);
504 p->tcf_tm.lastuse = jiffies;
505 bstats_update(&p->tcf_bstats, skb);
506 action = p->tcf_action;
507 update_flags = p->update_flags;
508 spin_unlock(&p->tcf_lock);
509
510 if (unlikely(action == TC_ACT_SHOT))
511 goto drop;
512
513 switch (tc_skb_protocol(skb)) {
514 case cpu_to_be16(ETH_P_IP):
515 if (!tcf_csum_ipv4(skb, update_flags))
516 goto drop;
517 break;
518 case cpu_to_be16(ETH_P_IPV6):
519 if (!tcf_csum_ipv6(skb, update_flags))
520 goto drop;
521 break;
522 }
523
524 return action;
525
526drop:
527 spin_lock(&p->tcf_lock);
528 p->tcf_qstats.drops++;
529 spin_unlock(&p->tcf_lock);
530 return TC_ACT_SHOT;
531}
532
533static int tcf_csum_dump(struct sk_buff *skb,
534 struct tc_action *a, int bind, int ref)
535{
536 unsigned char *b = skb_tail_pointer(skb);
537 struct tcf_csum *p = a->priv;
538 struct tc_csum opt = {
539 .update_flags = p->update_flags,
540 .index = p->tcf_index,
541 .action = p->tcf_action,
542 .refcnt = p->tcf_refcnt - ref,
543 .bindcnt = p->tcf_bindcnt - bind,
544 };
545 struct tcf_t t;
546
547 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
548 goto nla_put_failure;
549 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
550 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
551 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
552 if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
553 goto nla_put_failure;
554
555 return skb->len;
556
557nla_put_failure:
558 nlmsg_trim(skb, b);
559 return -1;
560}
561
562static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
563 struct netlink_callback *cb, int type,
564 struct tc_action *a)
565{
566 struct tc_action_net *tn = net_generic(net, csum_net_id);
567
568 return tcf_generic_walker(tn, skb, cb, type, a);
569}
570
571static int tcf_csum_search(struct net *net, struct tc_action *a, u32 index)
572{
573 struct tc_action_net *tn = net_generic(net, csum_net_id);
574
575 return tcf_hash_search(tn, a, index);
576}
577
578static struct tc_action_ops act_csum_ops = {
579 .kind = "csum",
580 .type = TCA_ACT_CSUM,
581 .owner = THIS_MODULE,
582 .act = tcf_csum,
583 .dump = tcf_csum_dump,
584 .init = tcf_csum_init,
585 .walk = tcf_csum_walker,
586 .lookup = tcf_csum_search,
587};
588
589static __net_init int csum_init_net(struct net *net)
590{
591 struct tc_action_net *tn = net_generic(net, csum_net_id);
592
593 return tc_action_net_init(tn, &act_csum_ops, CSUM_TAB_MASK);
594}
595
596static void __net_exit csum_exit_net(struct net *net)
597{
598 struct tc_action_net *tn = net_generic(net, csum_net_id);
599
600 tc_action_net_exit(tn);
601}
602
603static struct pernet_operations csum_net_ops = {
604 .init = csum_init_net,
605 .exit = csum_exit_net,
606 .id = &csum_net_id,
607 .size = sizeof(struct tc_action_net),
608};
609
610MODULE_DESCRIPTION("Checksum updating actions");
611MODULE_LICENSE("GPL");
612
613static int __init csum_init_module(void)
614{
615 return tcf_register_action(&act_csum_ops, &csum_net_ops);
616}
617
618static void __exit csum_cleanup_module(void)
619{
620 tcf_unregister_action(&act_csum_ops, &csum_net_ops);
621}
622
623module_init(csum_init_module);
624module_exit(csum_cleanup_module);
1/*
2 * Checksum updating actions
3 *
4 * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <linux/types.h>
14#include <linux/init.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/spinlock.h>
18
19#include <linux/netlink.h>
20#include <net/netlink.h>
21#include <linux/rtnetlink.h>
22
23#include <linux/skbuff.h>
24
25#include <net/ip.h>
26#include <net/ipv6.h>
27#include <net/icmp.h>
28#include <linux/icmpv6.h>
29#include <linux/igmp.h>
30#include <net/tcp.h>
31#include <net/udp.h>
32#include <net/ip6_checksum.h>
33
34#include <net/act_api.h>
35
36#include <linux/tc_act/tc_csum.h>
37#include <net/tc_act/tc_csum.h>
38
39#define CSUM_TAB_MASK 15
40static struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
41static u32 csum_idx_gen;
42static DEFINE_RWLOCK(csum_lock);
43
44static struct tcf_hashinfo csum_hash_info = {
45 .htab = tcf_csum_ht,
46 .hmask = CSUM_TAB_MASK,
47 .lock = &csum_lock,
48};
49
50static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
51 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
52};
53
54static int tcf_csum_init(struct nlattr *nla, struct nlattr *est,
55 struct tc_action *a, int ovr, int bind)
56{
57 struct nlattr *tb[TCA_CSUM_MAX + 1];
58 struct tc_csum *parm;
59 struct tcf_common *pc;
60 struct tcf_csum *p;
61 int ret = 0, err;
62
63 if (nla == NULL)
64 return -EINVAL;
65
66 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
67 if (err < 0)
68 return err;
69
70 if (tb[TCA_CSUM_PARMS] == NULL)
71 return -EINVAL;
72 parm = nla_data(tb[TCA_CSUM_PARMS]);
73
74 pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
75 if (!pc) {
76 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
77 &csum_idx_gen, &csum_hash_info);
78 if (IS_ERR(pc))
79 return PTR_ERR(pc);
80 p = to_tcf_csum(pc);
81 ret = ACT_P_CREATED;
82 } else {
83 p = to_tcf_csum(pc);
84 if (!ovr) {
85 tcf_hash_release(pc, bind, &csum_hash_info);
86 return -EEXIST;
87 }
88 }
89
90 spin_lock_bh(&p->tcf_lock);
91 p->tcf_action = parm->action;
92 p->update_flags = parm->update_flags;
93 spin_unlock_bh(&p->tcf_lock);
94
95 if (ret == ACT_P_CREATED)
96 tcf_hash_insert(pc, &csum_hash_info);
97
98 return ret;
99}
100
101static int tcf_csum_cleanup(struct tc_action *a, int bind)
102{
103 struct tcf_csum *p = a->priv;
104 return tcf_hash_release(&p->common, bind, &csum_hash_info);
105}
106
107/**
108 * tcf_csum_skb_nextlayer - Get next layer pointer
109 * @skb: sk_buff to use
110 * @ihl: previous summed headers length
111 * @ipl: complete packet length
112 * @jhl: next header length
113 *
114 * Check the expected next layer availability in the specified sk_buff.
115 * Return the next layer pointer if pass, NULL otherwise.
116 */
117static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
118 unsigned int ihl, unsigned int ipl,
119 unsigned int jhl)
120{
121 int ntkoff = skb_network_offset(skb);
122 int hl = ihl + jhl;
123
124 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
125 (skb_cloned(skb) &&
126 !skb_clone_writable(skb, hl + ntkoff) &&
127 pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
128 return NULL;
129 else
130 return (void *)(skb_network_header(skb) + ihl);
131}
132
133static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
134 unsigned int ihl, unsigned int ipl)
135{
136 struct icmphdr *icmph;
137
138 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
139 if (icmph == NULL)
140 return 0;
141
142 icmph->checksum = 0;
143 skb->csum = csum_partial(icmph, ipl - ihl, 0);
144 icmph->checksum = csum_fold(skb->csum);
145
146 skb->ip_summed = CHECKSUM_NONE;
147
148 return 1;
149}
150
151static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
152 unsigned int ihl, unsigned int ipl)
153{
154 struct igmphdr *igmph;
155
156 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
157 if (igmph == NULL)
158 return 0;
159
160 igmph->csum = 0;
161 skb->csum = csum_partial(igmph, ipl - ihl, 0);
162 igmph->csum = csum_fold(skb->csum);
163
164 skb->ip_summed = CHECKSUM_NONE;
165
166 return 1;
167}
168
169static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
170 unsigned int ihl, unsigned int ipl)
171{
172 struct icmp6hdr *icmp6h;
173
174 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
175 if (icmp6h == NULL)
176 return 0;
177
178 icmp6h->icmp6_cksum = 0;
179 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
180 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
181 ipl - ihl, IPPROTO_ICMPV6,
182 skb->csum);
183
184 skb->ip_summed = CHECKSUM_NONE;
185
186 return 1;
187}
188
189static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
190 unsigned int ihl, unsigned int ipl)
191{
192 struct tcphdr *tcph;
193
194 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
195 if (tcph == NULL)
196 return 0;
197
198 tcph->check = 0;
199 skb->csum = csum_partial(tcph, ipl - ihl, 0);
200 tcph->check = tcp_v4_check(ipl - ihl,
201 iph->saddr, iph->daddr, skb->csum);
202
203 skb->ip_summed = CHECKSUM_NONE;
204
205 return 1;
206}
207
208static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
209 unsigned int ihl, unsigned int ipl)
210{
211 struct tcphdr *tcph;
212
213 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
214 if (tcph == NULL)
215 return 0;
216
217 tcph->check = 0;
218 skb->csum = csum_partial(tcph, ipl - ihl, 0);
219 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
220 ipl - ihl, IPPROTO_TCP,
221 skb->csum);
222
223 skb->ip_summed = CHECKSUM_NONE;
224
225 return 1;
226}
227
228static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
229 unsigned int ihl, unsigned int ipl, int udplite)
230{
231 struct udphdr *udph;
232 u16 ul;
233
234 /*
235 * Support both UDP and UDPLITE checksum algorithms, Don't use
236 * udph->len to get the real length without any protocol check,
237 * UDPLITE uses udph->len for another thing,
238 * Use iph->tot_len, or just ipl.
239 */
240
241 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
242 if (udph == NULL)
243 return 0;
244
245 ul = ntohs(udph->len);
246
247 if (udplite || udph->check) {
248
249 udph->check = 0;
250
251 if (udplite) {
252 if (ul == 0)
253 skb->csum = csum_partial(udph, ipl - ihl, 0);
254 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
255 skb->csum = csum_partial(udph, ul, 0);
256 else
257 goto ignore_obscure_skb;
258 } else {
259 if (ul != ipl - ihl)
260 goto ignore_obscure_skb;
261
262 skb->csum = csum_partial(udph, ul, 0);
263 }
264
265 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
266 ul, iph->protocol,
267 skb->csum);
268
269 if (!udph->check)
270 udph->check = CSUM_MANGLED_0;
271 }
272
273 skb->ip_summed = CHECKSUM_NONE;
274
275ignore_obscure_skb:
276 return 1;
277}
278
279static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
280 unsigned int ihl, unsigned int ipl, int udplite)
281{
282 struct udphdr *udph;
283 u16 ul;
284
285 /*
286 * Support both UDP and UDPLITE checksum algorithms, Don't use
287 * udph->len to get the real length without any protocol check,
288 * UDPLITE uses udph->len for another thing,
289 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
290 */
291
292 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
293 if (udph == NULL)
294 return 0;
295
296 ul = ntohs(udph->len);
297
298 udph->check = 0;
299
300 if (udplite) {
301 if (ul == 0)
302 skb->csum = csum_partial(udph, ipl - ihl, 0);
303
304 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
305 skb->csum = csum_partial(udph, ul, 0);
306
307 else
308 goto ignore_obscure_skb;
309 } else {
310 if (ul != ipl - ihl)
311 goto ignore_obscure_skb;
312
313 skb->csum = csum_partial(udph, ul, 0);
314 }
315
316 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
317 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
318 skb->csum);
319
320 if (!udph->check)
321 udph->check = CSUM_MANGLED_0;
322
323 skb->ip_summed = CHECKSUM_NONE;
324
325ignore_obscure_skb:
326 return 1;
327}
328
329static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
330{
331 struct iphdr *iph;
332 int ntkoff;
333
334 ntkoff = skb_network_offset(skb);
335
336 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
337 goto fail;
338
339 iph = ip_hdr(skb);
340
341 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
342 case IPPROTO_ICMP:
343 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
344 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
345 ntohs(iph->tot_len)))
346 goto fail;
347 break;
348 case IPPROTO_IGMP:
349 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
350 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
351 ntohs(iph->tot_len)))
352 goto fail;
353 break;
354 case IPPROTO_TCP:
355 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
356 if (!tcf_csum_ipv4_tcp(skb, iph, iph->ihl * 4,
357 ntohs(iph->tot_len)))
358 goto fail;
359 break;
360 case IPPROTO_UDP:
361 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
362 if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
363 ntohs(iph->tot_len), 0))
364 goto fail;
365 break;
366 case IPPROTO_UDPLITE:
367 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
368 if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
369 ntohs(iph->tot_len), 1))
370 goto fail;
371 break;
372 }
373
374 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
375 if (skb_cloned(skb) &&
376 !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
377 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
378 goto fail;
379
380 ip_send_check(iph);
381 }
382
383 return 1;
384
385fail:
386 return 0;
387}
388
389static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
390 unsigned int ixhl, unsigned int *pl)
391{
392 int off, len, optlen;
393 unsigned char *xh = (void *)ip6xh;
394
395 off = sizeof(*ip6xh);
396 len = ixhl - off;
397
398 while (len > 1) {
399 switch (xh[off]) {
400 case IPV6_TLV_PAD1:
401 optlen = 1;
402 break;
403 case IPV6_TLV_JUMBO:
404 optlen = xh[off + 1] + 2;
405 if (optlen != 6 || len < 6 || (off & 3) != 2)
406 /* wrong jumbo option length/alignment */
407 return 0;
408 *pl = ntohl(*(__be32 *)(xh + off + 2));
409 goto done;
410 default:
411 optlen = xh[off + 1] + 2;
412 if (optlen > len)
413 /* ignore obscure options */
414 goto done;
415 break;
416 }
417 off += optlen;
418 len -= optlen;
419 }
420
421done:
422 return 1;
423}
424
425static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
426{
427 struct ipv6hdr *ip6h;
428 struct ipv6_opt_hdr *ip6xh;
429 unsigned int hl, ixhl;
430 unsigned int pl;
431 int ntkoff;
432 u8 nexthdr;
433
434 ntkoff = skb_network_offset(skb);
435
436 hl = sizeof(*ip6h);
437
438 if (!pskb_may_pull(skb, hl + ntkoff))
439 goto fail;
440
441 ip6h = ipv6_hdr(skb);
442
443 pl = ntohs(ip6h->payload_len);
444 nexthdr = ip6h->nexthdr;
445
446 do {
447 switch (nexthdr) {
448 case NEXTHDR_FRAGMENT:
449 goto ignore_skb;
450 case NEXTHDR_ROUTING:
451 case NEXTHDR_HOP:
452 case NEXTHDR_DEST:
453 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
454 goto fail;
455 ip6xh = (void *)(skb_network_header(skb) + hl);
456 ixhl = ipv6_optlen(ip6xh);
457 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
458 goto fail;
459 if ((nexthdr == NEXTHDR_HOP) &&
460 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
461 goto fail;
462 nexthdr = ip6xh->nexthdr;
463 hl += ixhl;
464 break;
465 case IPPROTO_ICMPV6:
466 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
467 if (!tcf_csum_ipv6_icmp(skb, ip6h,
468 hl, pl + sizeof(*ip6h)))
469 goto fail;
470 goto done;
471 case IPPROTO_TCP:
472 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
473 if (!tcf_csum_ipv6_tcp(skb, ip6h,
474 hl, pl + sizeof(*ip6h)))
475 goto fail;
476 goto done;
477 case IPPROTO_UDP:
478 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
479 if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
480 pl + sizeof(*ip6h), 0))
481 goto fail;
482 goto done;
483 case IPPROTO_UDPLITE:
484 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
485 if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
486 pl + sizeof(*ip6h), 1))
487 goto fail;
488 goto done;
489 default:
490 goto ignore_skb;
491 }
492 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
493
494done:
495ignore_skb:
496 return 1;
497
498fail:
499 return 0;
500}
501
502static int tcf_csum(struct sk_buff *skb,
503 const struct tc_action *a, struct tcf_result *res)
504{
505 struct tcf_csum *p = a->priv;
506 int action;
507 u32 update_flags;
508
509 spin_lock(&p->tcf_lock);
510 p->tcf_tm.lastuse = jiffies;
511 bstats_update(&p->tcf_bstats, skb);
512 action = p->tcf_action;
513 update_flags = p->update_flags;
514 spin_unlock(&p->tcf_lock);
515
516 if (unlikely(action == TC_ACT_SHOT))
517 goto drop;
518
519 switch (skb->protocol) {
520 case cpu_to_be16(ETH_P_IP):
521 if (!tcf_csum_ipv4(skb, update_flags))
522 goto drop;
523 break;
524 case cpu_to_be16(ETH_P_IPV6):
525 if (!tcf_csum_ipv6(skb, update_flags))
526 goto drop;
527 break;
528 }
529
530 return action;
531
532drop:
533 spin_lock(&p->tcf_lock);
534 p->tcf_qstats.drops++;
535 spin_unlock(&p->tcf_lock);
536 return TC_ACT_SHOT;
537}
538
539static int tcf_csum_dump(struct sk_buff *skb,
540 struct tc_action *a, int bind, int ref)
541{
542 unsigned char *b = skb_tail_pointer(skb);
543 struct tcf_csum *p = a->priv;
544 struct tc_csum opt = {
545 .update_flags = p->update_flags,
546 .index = p->tcf_index,
547 .action = p->tcf_action,
548 .refcnt = p->tcf_refcnt - ref,
549 .bindcnt = p->tcf_bindcnt - bind,
550 };
551 struct tcf_t t;
552
553 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
554 goto nla_put_failure;
555 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
556 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
557 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
558 if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
559 goto nla_put_failure;
560
561 return skb->len;
562
563nla_put_failure:
564 nlmsg_trim(skb, b);
565 return -1;
566}
567
568static struct tc_action_ops act_csum_ops = {
569 .kind = "csum",
570 .hinfo = &csum_hash_info,
571 .type = TCA_ACT_CSUM,
572 .capab = TCA_CAP_NONE,
573 .owner = THIS_MODULE,
574 .act = tcf_csum,
575 .dump = tcf_csum_dump,
576 .cleanup = tcf_csum_cleanup,
577 .lookup = tcf_hash_search,
578 .init = tcf_csum_init,
579 .walk = tcf_generic_walker
580};
581
582MODULE_DESCRIPTION("Checksum updating actions");
583MODULE_LICENSE("GPL");
584
585static int __init csum_init_module(void)
586{
587 return tcf_register_action(&act_csum_ops);
588}
589
590static void __exit csum_cleanup_module(void)
591{
592 tcf_unregister_action(&act_csum_ops);
593}
594
595module_init(csum_init_module);
596module_exit(csum_cleanup_module);