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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
40
41static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
42 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
43};
44
45static unsigned int csum_net_id;
46static struct tc_action_ops act_csum_ops;
47
48static int tcf_csum_init(struct net *net, struct nlattr *nla,
49 struct nlattr *est, struct tc_action **a, int ovr,
50 int bind)
51{
52 struct tc_action_net *tn = net_generic(net, csum_net_id);
53 struct nlattr *tb[TCA_CSUM_MAX + 1];
54 struct tc_csum *parm;
55 struct tcf_csum *p;
56 int ret = 0, err;
57
58 if (nla == NULL)
59 return -EINVAL;
60
61 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
62 if (err < 0)
63 return err;
64
65 if (tb[TCA_CSUM_PARMS] == NULL)
66 return -EINVAL;
67 parm = nla_data(tb[TCA_CSUM_PARMS]);
68
69 if (!tcf_hash_check(tn, parm->index, a, bind)) {
70 ret = tcf_hash_create(tn, parm->index, est, a,
71 &act_csum_ops, bind, false);
72 if (ret)
73 return ret;
74 ret = ACT_P_CREATED;
75 } else {
76 if (bind)/* dont override defaults */
77 return 0;
78 tcf_hash_release(*a, bind);
79 if (!ovr)
80 return -EEXIST;
81 }
82
83 p = to_tcf_csum(*a);
84 spin_lock_bh(&p->tcf_lock);
85 p->tcf_action = parm->action;
86 p->update_flags = parm->update_flags;
87 spin_unlock_bh(&p->tcf_lock);
88
89 if (ret == ACT_P_CREATED)
90 tcf_hash_insert(tn, *a);
91
92 return ret;
93}
94
95/**
96 * tcf_csum_skb_nextlayer - Get next layer pointer
97 * @skb: sk_buff to use
98 * @ihl: previous summed headers length
99 * @ipl: complete packet length
100 * @jhl: next header length
101 *
102 * Check the expected next layer availability in the specified sk_buff.
103 * Return the next layer pointer if pass, NULL otherwise.
104 */
105static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
106 unsigned int ihl, unsigned int ipl,
107 unsigned int jhl)
108{
109 int ntkoff = skb_network_offset(skb);
110 int hl = ihl + jhl;
111
112 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
113 skb_try_make_writable(skb, hl + ntkoff))
114 return NULL;
115 else
116 return (void *)(skb_network_header(skb) + ihl);
117}
118
119static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
120 unsigned int ipl)
121{
122 struct icmphdr *icmph;
123
124 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
125 if (icmph == NULL)
126 return 0;
127
128 icmph->checksum = 0;
129 skb->csum = csum_partial(icmph, ipl - ihl, 0);
130 icmph->checksum = csum_fold(skb->csum);
131
132 skb->ip_summed = CHECKSUM_NONE;
133
134 return 1;
135}
136
137static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
138 unsigned int ihl, unsigned int ipl)
139{
140 struct igmphdr *igmph;
141
142 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
143 if (igmph == NULL)
144 return 0;
145
146 igmph->csum = 0;
147 skb->csum = csum_partial(igmph, ipl - ihl, 0);
148 igmph->csum = csum_fold(skb->csum);
149
150 skb->ip_summed = CHECKSUM_NONE;
151
152 return 1;
153}
154
155static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
156 unsigned int ipl)
157{
158 struct icmp6hdr *icmp6h;
159 const struct ipv6hdr *ip6h;
160
161 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
162 if (icmp6h == NULL)
163 return 0;
164
165 ip6h = ipv6_hdr(skb);
166 icmp6h->icmp6_cksum = 0;
167 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
168 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
169 ipl - ihl, IPPROTO_ICMPV6,
170 skb->csum);
171
172 skb->ip_summed = CHECKSUM_NONE;
173
174 return 1;
175}
176
177static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
178 unsigned int ipl)
179{
180 struct tcphdr *tcph;
181 const struct iphdr *iph;
182
183 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
184 if (tcph == NULL)
185 return 0;
186
187 iph = ip_hdr(skb);
188 tcph->check = 0;
189 skb->csum = csum_partial(tcph, ipl - ihl, 0);
190 tcph->check = tcp_v4_check(ipl - ihl,
191 iph->saddr, iph->daddr, skb->csum);
192
193 skb->ip_summed = CHECKSUM_NONE;
194
195 return 1;
196}
197
198static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
199 unsigned int ipl)
200{
201 struct tcphdr *tcph;
202 const struct ipv6hdr *ip6h;
203
204 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
205 if (tcph == NULL)
206 return 0;
207
208 ip6h = ipv6_hdr(skb);
209 tcph->check = 0;
210 skb->csum = csum_partial(tcph, ipl - ihl, 0);
211 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
212 ipl - ihl, IPPROTO_TCP,
213 skb->csum);
214
215 skb->ip_summed = CHECKSUM_NONE;
216
217 return 1;
218}
219
220static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
221 unsigned int ipl, int udplite)
222{
223 struct udphdr *udph;
224 const struct iphdr *iph;
225 u16 ul;
226
227 /*
228 * Support both UDP and UDPLITE checksum algorithms, Don't use
229 * udph->len to get the real length without any protocol check,
230 * UDPLITE uses udph->len for another thing,
231 * Use iph->tot_len, or just ipl.
232 */
233
234 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
235 if (udph == NULL)
236 return 0;
237
238 iph = ip_hdr(skb);
239 ul = ntohs(udph->len);
240
241 if (udplite || udph->check) {
242
243 udph->check = 0;
244
245 if (udplite) {
246 if (ul == 0)
247 skb->csum = csum_partial(udph, ipl - ihl, 0);
248 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
249 skb->csum = csum_partial(udph, ul, 0);
250 else
251 goto ignore_obscure_skb;
252 } else {
253 if (ul != ipl - ihl)
254 goto ignore_obscure_skb;
255
256 skb->csum = csum_partial(udph, ul, 0);
257 }
258
259 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
260 ul, iph->protocol,
261 skb->csum);
262
263 if (!udph->check)
264 udph->check = CSUM_MANGLED_0;
265 }
266
267 skb->ip_summed = CHECKSUM_NONE;
268
269ignore_obscure_skb:
270 return 1;
271}
272
273static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
274 unsigned int ipl, int udplite)
275{
276 struct udphdr *udph;
277 const struct ipv6hdr *ip6h;
278 u16 ul;
279
280 /*
281 * Support both UDP and UDPLITE checksum algorithms, Don't use
282 * udph->len to get the real length without any protocol check,
283 * UDPLITE uses udph->len for another thing,
284 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
285 */
286
287 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
288 if (udph == NULL)
289 return 0;
290
291 ip6h = ipv6_hdr(skb);
292 ul = ntohs(udph->len);
293
294 udph->check = 0;
295
296 if (udplite) {
297 if (ul == 0)
298 skb->csum = csum_partial(udph, ipl - ihl, 0);
299
300 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
301 skb->csum = csum_partial(udph, ul, 0);
302
303 else
304 goto ignore_obscure_skb;
305 } else {
306 if (ul != ipl - ihl)
307 goto ignore_obscure_skb;
308
309 skb->csum = csum_partial(udph, ul, 0);
310 }
311
312 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
313 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
314 skb->csum);
315
316 if (!udph->check)
317 udph->check = CSUM_MANGLED_0;
318
319 skb->ip_summed = CHECKSUM_NONE;
320
321ignore_obscure_skb:
322 return 1;
323}
324
325static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
326{
327 const struct iphdr *iph;
328 int ntkoff;
329
330 ntkoff = skb_network_offset(skb);
331
332 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
333 goto fail;
334
335 iph = ip_hdr(skb);
336
337 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
338 case IPPROTO_ICMP:
339 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
340 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
341 ntohs(iph->tot_len)))
342 goto fail;
343 break;
344 case IPPROTO_IGMP:
345 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
346 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
347 ntohs(iph->tot_len)))
348 goto fail;
349 break;
350 case IPPROTO_TCP:
351 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
352 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
353 ntohs(iph->tot_len)))
354 goto fail;
355 break;
356 case IPPROTO_UDP:
357 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
358 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
359 ntohs(iph->tot_len), 0))
360 goto fail;
361 break;
362 case IPPROTO_UDPLITE:
363 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
364 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
365 ntohs(iph->tot_len), 1))
366 goto fail;
367 break;
368 }
369
370 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
371 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
372 goto fail;
373
374 ip_send_check(ip_hdr(skb));
375 }
376
377 return 1;
378
379fail:
380 return 0;
381}
382
383static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
384 unsigned int *pl)
385{
386 int off, len, optlen;
387 unsigned char *xh = (void *)ip6xh;
388
389 off = sizeof(*ip6xh);
390 len = ixhl - off;
391
392 while (len > 1) {
393 switch (xh[off]) {
394 case IPV6_TLV_PAD1:
395 optlen = 1;
396 break;
397 case IPV6_TLV_JUMBO:
398 optlen = xh[off + 1] + 2;
399 if (optlen != 6 || len < 6 || (off & 3) != 2)
400 /* wrong jumbo option length/alignment */
401 return 0;
402 *pl = ntohl(*(__be32 *)(xh + off + 2));
403 goto done;
404 default:
405 optlen = xh[off + 1] + 2;
406 if (optlen > len)
407 /* ignore obscure options */
408 goto done;
409 break;
410 }
411 off += optlen;
412 len -= optlen;
413 }
414
415done:
416 return 1;
417}
418
419static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
420{
421 struct ipv6hdr *ip6h;
422 struct ipv6_opt_hdr *ip6xh;
423 unsigned int hl, ixhl;
424 unsigned int pl;
425 int ntkoff;
426 u8 nexthdr;
427
428 ntkoff = skb_network_offset(skb);
429
430 hl = sizeof(*ip6h);
431
432 if (!pskb_may_pull(skb, hl + ntkoff))
433 goto fail;
434
435 ip6h = ipv6_hdr(skb);
436
437 pl = ntohs(ip6h->payload_len);
438 nexthdr = ip6h->nexthdr;
439
440 do {
441 switch (nexthdr) {
442 case NEXTHDR_FRAGMENT:
443 goto ignore_skb;
444 case NEXTHDR_ROUTING:
445 case NEXTHDR_HOP:
446 case NEXTHDR_DEST:
447 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
448 goto fail;
449 ip6xh = (void *)(skb_network_header(skb) + hl);
450 ixhl = ipv6_optlen(ip6xh);
451 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
452 goto fail;
453 ip6xh = (void *)(skb_network_header(skb) + hl);
454 if ((nexthdr == NEXTHDR_HOP) &&
455 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
456 goto fail;
457 nexthdr = ip6xh->nexthdr;
458 hl += ixhl;
459 break;
460 case IPPROTO_ICMPV6:
461 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
462 if (!tcf_csum_ipv6_icmp(skb,
463 hl, pl + sizeof(*ip6h)))
464 goto fail;
465 goto done;
466 case IPPROTO_TCP:
467 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
468 if (!tcf_csum_ipv6_tcp(skb,
469 hl, pl + sizeof(*ip6h)))
470 goto fail;
471 goto done;
472 case IPPROTO_UDP:
473 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
474 if (!tcf_csum_ipv6_udp(skb, hl,
475 pl + sizeof(*ip6h), 0))
476 goto fail;
477 goto done;
478 case IPPROTO_UDPLITE:
479 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
480 if (!tcf_csum_ipv6_udp(skb, hl,
481 pl + sizeof(*ip6h), 1))
482 goto fail;
483 goto done;
484 default:
485 goto ignore_skb;
486 }
487 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
488
489done:
490ignore_skb:
491 return 1;
492
493fail:
494 return 0;
495}
496
497static int tcf_csum(struct sk_buff *skb, const struct tc_action *a,
498 struct tcf_result *res)
499{
500 struct tcf_csum *p = to_tcf_csum(a);
501 int action;
502 u32 update_flags;
503
504 spin_lock(&p->tcf_lock);
505 tcf_lastuse_update(&p->tcf_tm);
506 bstats_update(&p->tcf_bstats, skb);
507 action = p->tcf_action;
508 update_flags = p->update_flags;
509 spin_unlock(&p->tcf_lock);
510
511 if (unlikely(action == TC_ACT_SHOT))
512 goto drop;
513
514 switch (tc_skb_protocol(skb)) {
515 case cpu_to_be16(ETH_P_IP):
516 if (!tcf_csum_ipv4(skb, update_flags))
517 goto drop;
518 break;
519 case cpu_to_be16(ETH_P_IPV6):
520 if (!tcf_csum_ipv6(skb, update_flags))
521 goto drop;
522 break;
523 }
524
525 return action;
526
527drop:
528 spin_lock(&p->tcf_lock);
529 p->tcf_qstats.drops++;
530 spin_unlock(&p->tcf_lock);
531 return TC_ACT_SHOT;
532}
533
534static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
535 int ref)
536{
537 unsigned char *b = skb_tail_pointer(skb);
538 struct tcf_csum *p = to_tcf_csum(a);
539 struct tc_csum opt = {
540 .update_flags = p->update_flags,
541 .index = p->tcf_index,
542 .action = p->tcf_action,
543 .refcnt = p->tcf_refcnt - ref,
544 .bindcnt = p->tcf_bindcnt - bind,
545 };
546 struct tcf_t t;
547
548 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
549 goto nla_put_failure;
550
551 tcf_tm_dump(&t, &p->tcf_tm);
552 if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
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 const struct tc_action_ops *ops)
565{
566 struct tc_action_net *tn = net_generic(net, csum_net_id);
567
568 return tcf_generic_walker(tn, skb, cb, type, ops);
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 .size = sizeof(struct tcf_csum),
588};
589
590static __net_init int csum_init_net(struct net *net)
591{
592 struct tc_action_net *tn = net_generic(net, csum_net_id);
593
594 return tc_action_net_init(tn, &act_csum_ops, CSUM_TAB_MASK);
595}
596
597static void __net_exit csum_exit_net(struct net *net)
598{
599 struct tc_action_net *tn = net_generic(net, csum_net_id);
600
601 tc_action_net_exit(tn);
602}
603
604static struct pernet_operations csum_net_ops = {
605 .init = csum_init_net,
606 .exit = csum_exit_net,
607 .id = &csum_net_id,
608 .size = sizeof(struct tc_action_net),
609};
610
611MODULE_DESCRIPTION("Checksum updating actions");
612MODULE_LICENSE("GPL");
613
614static int __init csum_init_module(void)
615{
616 return tcf_register_action(&act_csum_ops, &csum_net_ops);
617}
618
619static void __exit csum_cleanup_module(void)
620{
621 tcf_unregister_action(&act_csum_ops, &csum_net_ops);
622}
623
624module_init(csum_init_module);
625module_exit(csum_cleanup_module);