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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#include <net/sctp/checksum.h>
34
35#include <net/act_api.h>
36
37#include <linux/tc_act/tc_csum.h>
38#include <net/tc_act/tc_csum.h>
39
40static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
41 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
42};
43
44static unsigned int csum_net_id;
45static struct tc_action_ops act_csum_ops;
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, struct netlink_ext_ack *extack)
50{
51 struct tc_action_net *tn = net_generic(net, csum_net_id);
52 struct tcf_csum_params *params_old, *params_new;
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, NULL);
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_idr_check(tn, parm->index, a, bind)) {
70 ret = tcf_idr_create(tn, parm->index, est, a,
71 &act_csum_ops, bind, true);
72 if (ret)
73 return ret;
74 ret = ACT_P_CREATED;
75 } else {
76 if (bind)/* dont override defaults */
77 return 0;
78 tcf_idr_release(*a, bind);
79 if (!ovr)
80 return -EEXIST;
81 }
82
83 p = to_tcf_csum(*a);
84 ASSERT_RTNL();
85
86 params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
87 if (unlikely(!params_new)) {
88 if (ret == ACT_P_CREATED)
89 tcf_idr_release(*a, bind);
90 return -ENOMEM;
91 }
92 params_old = rtnl_dereference(p->params);
93
94 params_new->action = parm->action;
95 params_new->update_flags = parm->update_flags;
96 rcu_assign_pointer(p->params, params_new);
97 if (params_old)
98 kfree_rcu(params_old, rcu);
99
100 if (ret == ACT_P_CREATED)
101 tcf_idr_insert(tn, *a);
102
103 return ret;
104}
105
106/**
107 * tcf_csum_skb_nextlayer - Get next layer pointer
108 * @skb: sk_buff to use
109 * @ihl: previous summed headers length
110 * @ipl: complete packet length
111 * @jhl: next header length
112 *
113 * Check the expected next layer availability in the specified sk_buff.
114 * Return the next layer pointer if pass, NULL otherwise.
115 */
116static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
117 unsigned int ihl, unsigned int ipl,
118 unsigned int jhl)
119{
120 int ntkoff = skb_network_offset(skb);
121 int hl = ihl + jhl;
122
123 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
124 skb_try_make_writable(skb, hl + ntkoff))
125 return NULL;
126 else
127 return (void *)(skb_network_header(skb) + ihl);
128}
129
130static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
131 unsigned int ipl)
132{
133 struct icmphdr *icmph;
134
135 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
136 if (icmph == NULL)
137 return 0;
138
139 icmph->checksum = 0;
140 skb->csum = csum_partial(icmph, ipl - ihl, 0);
141 icmph->checksum = csum_fold(skb->csum);
142
143 skb->ip_summed = CHECKSUM_NONE;
144
145 return 1;
146}
147
148static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
149 unsigned int ihl, unsigned int ipl)
150{
151 struct igmphdr *igmph;
152
153 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
154 if (igmph == NULL)
155 return 0;
156
157 igmph->csum = 0;
158 skb->csum = csum_partial(igmph, ipl - ihl, 0);
159 igmph->csum = csum_fold(skb->csum);
160
161 skb->ip_summed = CHECKSUM_NONE;
162
163 return 1;
164}
165
166static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
167 unsigned int ipl)
168{
169 struct icmp6hdr *icmp6h;
170 const struct ipv6hdr *ip6h;
171
172 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
173 if (icmp6h == NULL)
174 return 0;
175
176 ip6h = ipv6_hdr(skb);
177 icmp6h->icmp6_cksum = 0;
178 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
179 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
180 ipl - ihl, IPPROTO_ICMPV6,
181 skb->csum);
182
183 skb->ip_summed = CHECKSUM_NONE;
184
185 return 1;
186}
187
188static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
189 unsigned int ipl)
190{
191 struct tcphdr *tcph;
192 const struct iphdr *iph;
193
194 if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
195 return 1;
196
197 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
198 if (tcph == NULL)
199 return 0;
200
201 iph = ip_hdr(skb);
202 tcph->check = 0;
203 skb->csum = csum_partial(tcph, ipl - ihl, 0);
204 tcph->check = tcp_v4_check(ipl - ihl,
205 iph->saddr, iph->daddr, skb->csum);
206
207 skb->ip_summed = CHECKSUM_NONE;
208
209 return 1;
210}
211
212static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
213 unsigned int ipl)
214{
215 struct tcphdr *tcph;
216 const struct ipv6hdr *ip6h;
217
218 if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
219 return 1;
220
221 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
222 if (tcph == NULL)
223 return 0;
224
225 ip6h = ipv6_hdr(skb);
226 tcph->check = 0;
227 skb->csum = csum_partial(tcph, ipl - ihl, 0);
228 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
229 ipl - ihl, IPPROTO_TCP,
230 skb->csum);
231
232 skb->ip_summed = CHECKSUM_NONE;
233
234 return 1;
235}
236
237static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
238 unsigned int ipl, int udplite)
239{
240 struct udphdr *udph;
241 const struct iphdr *iph;
242 u16 ul;
243
244 if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
245 return 1;
246
247 /*
248 * Support both UDP and UDPLITE checksum algorithms, Don't use
249 * udph->len to get the real length without any protocol check,
250 * UDPLITE uses udph->len for another thing,
251 * Use iph->tot_len, or just ipl.
252 */
253
254 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
255 if (udph == NULL)
256 return 0;
257
258 iph = ip_hdr(skb);
259 ul = ntohs(udph->len);
260
261 if (udplite || udph->check) {
262
263 udph->check = 0;
264
265 if (udplite) {
266 if (ul == 0)
267 skb->csum = csum_partial(udph, ipl - ihl, 0);
268 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
269 skb->csum = csum_partial(udph, ul, 0);
270 else
271 goto ignore_obscure_skb;
272 } else {
273 if (ul != ipl - ihl)
274 goto ignore_obscure_skb;
275
276 skb->csum = csum_partial(udph, ul, 0);
277 }
278
279 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
280 ul, iph->protocol,
281 skb->csum);
282
283 if (!udph->check)
284 udph->check = CSUM_MANGLED_0;
285 }
286
287 skb->ip_summed = CHECKSUM_NONE;
288
289ignore_obscure_skb:
290 return 1;
291}
292
293static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
294 unsigned int ipl, int udplite)
295{
296 struct udphdr *udph;
297 const struct ipv6hdr *ip6h;
298 u16 ul;
299
300 if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
301 return 1;
302
303 /*
304 * Support both UDP and UDPLITE checksum algorithms, Don't use
305 * udph->len to get the real length without any protocol check,
306 * UDPLITE uses udph->len for another thing,
307 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
308 */
309
310 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
311 if (udph == NULL)
312 return 0;
313
314 ip6h = ipv6_hdr(skb);
315 ul = ntohs(udph->len);
316
317 udph->check = 0;
318
319 if (udplite) {
320 if (ul == 0)
321 skb->csum = csum_partial(udph, ipl - ihl, 0);
322
323 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
324 skb->csum = csum_partial(udph, ul, 0);
325
326 else
327 goto ignore_obscure_skb;
328 } else {
329 if (ul != ipl - ihl)
330 goto ignore_obscure_skb;
331
332 skb->csum = csum_partial(udph, ul, 0);
333 }
334
335 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
336 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
337 skb->csum);
338
339 if (!udph->check)
340 udph->check = CSUM_MANGLED_0;
341
342 skb->ip_summed = CHECKSUM_NONE;
343
344ignore_obscure_skb:
345 return 1;
346}
347
348static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
349 unsigned int ipl)
350{
351 struct sctphdr *sctph;
352
353 if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
354 return 1;
355
356 sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
357 if (!sctph)
358 return 0;
359
360 sctph->checksum = sctp_compute_cksum(skb,
361 skb_network_offset(skb) + ihl);
362 skb->ip_summed = CHECKSUM_NONE;
363 skb->csum_not_inet = 0;
364
365 return 1;
366}
367
368static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
369{
370 const struct iphdr *iph;
371 int ntkoff;
372
373 ntkoff = skb_network_offset(skb);
374
375 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
376 goto fail;
377
378 iph = ip_hdr(skb);
379
380 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
381 case IPPROTO_ICMP:
382 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
383 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
384 ntohs(iph->tot_len)))
385 goto fail;
386 break;
387 case IPPROTO_IGMP:
388 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
389 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
390 ntohs(iph->tot_len)))
391 goto fail;
392 break;
393 case IPPROTO_TCP:
394 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
395 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
396 ntohs(iph->tot_len)))
397 goto fail;
398 break;
399 case IPPROTO_UDP:
400 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
401 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
402 ntohs(iph->tot_len), 0))
403 goto fail;
404 break;
405 case IPPROTO_UDPLITE:
406 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
407 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
408 ntohs(iph->tot_len), 1))
409 goto fail;
410 break;
411 case IPPROTO_SCTP:
412 if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
413 !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
414 goto fail;
415 break;
416 }
417
418 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
419 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
420 goto fail;
421
422 ip_send_check(ip_hdr(skb));
423 }
424
425 return 1;
426
427fail:
428 return 0;
429}
430
431static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
432 unsigned int *pl)
433{
434 int off, len, optlen;
435 unsigned char *xh = (void *)ip6xh;
436
437 off = sizeof(*ip6xh);
438 len = ixhl - off;
439
440 while (len > 1) {
441 switch (xh[off]) {
442 case IPV6_TLV_PAD1:
443 optlen = 1;
444 break;
445 case IPV6_TLV_JUMBO:
446 optlen = xh[off + 1] + 2;
447 if (optlen != 6 || len < 6 || (off & 3) != 2)
448 /* wrong jumbo option length/alignment */
449 return 0;
450 *pl = ntohl(*(__be32 *)(xh + off + 2));
451 goto done;
452 default:
453 optlen = xh[off + 1] + 2;
454 if (optlen > len)
455 /* ignore obscure options */
456 goto done;
457 break;
458 }
459 off += optlen;
460 len -= optlen;
461 }
462
463done:
464 return 1;
465}
466
467static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
468{
469 struct ipv6hdr *ip6h;
470 struct ipv6_opt_hdr *ip6xh;
471 unsigned int hl, ixhl;
472 unsigned int pl;
473 int ntkoff;
474 u8 nexthdr;
475
476 ntkoff = skb_network_offset(skb);
477
478 hl = sizeof(*ip6h);
479
480 if (!pskb_may_pull(skb, hl + ntkoff))
481 goto fail;
482
483 ip6h = ipv6_hdr(skb);
484
485 pl = ntohs(ip6h->payload_len);
486 nexthdr = ip6h->nexthdr;
487
488 do {
489 switch (nexthdr) {
490 case NEXTHDR_FRAGMENT:
491 goto ignore_skb;
492 case NEXTHDR_ROUTING:
493 case NEXTHDR_HOP:
494 case NEXTHDR_DEST:
495 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
496 goto fail;
497 ip6xh = (void *)(skb_network_header(skb) + hl);
498 ixhl = ipv6_optlen(ip6xh);
499 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
500 goto fail;
501 ip6xh = (void *)(skb_network_header(skb) + hl);
502 if ((nexthdr == NEXTHDR_HOP) &&
503 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
504 goto fail;
505 nexthdr = ip6xh->nexthdr;
506 hl += ixhl;
507 break;
508 case IPPROTO_ICMPV6:
509 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
510 if (!tcf_csum_ipv6_icmp(skb,
511 hl, pl + sizeof(*ip6h)))
512 goto fail;
513 goto done;
514 case IPPROTO_TCP:
515 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
516 if (!tcf_csum_ipv6_tcp(skb,
517 hl, pl + sizeof(*ip6h)))
518 goto fail;
519 goto done;
520 case IPPROTO_UDP:
521 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
522 if (!tcf_csum_ipv6_udp(skb, hl,
523 pl + sizeof(*ip6h), 0))
524 goto fail;
525 goto done;
526 case IPPROTO_UDPLITE:
527 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
528 if (!tcf_csum_ipv6_udp(skb, hl,
529 pl + sizeof(*ip6h), 1))
530 goto fail;
531 goto done;
532 case IPPROTO_SCTP:
533 if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
534 !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
535 goto fail;
536 goto done;
537 default:
538 goto ignore_skb;
539 }
540 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
541
542done:
543ignore_skb:
544 return 1;
545
546fail:
547 return 0;
548}
549
550static int tcf_csum(struct sk_buff *skb, const struct tc_action *a,
551 struct tcf_result *res)
552{
553 struct tcf_csum *p = to_tcf_csum(a);
554 struct tcf_csum_params *params;
555 u32 update_flags;
556 int action;
557
558 rcu_read_lock();
559 params = rcu_dereference(p->params);
560
561 tcf_lastuse_update(&p->tcf_tm);
562 bstats_cpu_update(this_cpu_ptr(p->common.cpu_bstats), skb);
563
564 action = params->action;
565 if (unlikely(action == TC_ACT_SHOT))
566 goto drop_stats;
567
568 update_flags = params->update_flags;
569 switch (tc_skb_protocol(skb)) {
570 case cpu_to_be16(ETH_P_IP):
571 if (!tcf_csum_ipv4(skb, update_flags))
572 goto drop;
573 break;
574 case cpu_to_be16(ETH_P_IPV6):
575 if (!tcf_csum_ipv6(skb, update_flags))
576 goto drop;
577 break;
578 }
579
580unlock:
581 rcu_read_unlock();
582 return action;
583
584drop:
585 action = TC_ACT_SHOT;
586
587drop_stats:
588 qstats_drop_inc(this_cpu_ptr(p->common.cpu_qstats));
589 goto unlock;
590}
591
592static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
593 int ref)
594{
595 unsigned char *b = skb_tail_pointer(skb);
596 struct tcf_csum *p = to_tcf_csum(a);
597 struct tcf_csum_params *params;
598 struct tc_csum opt = {
599 .index = p->tcf_index,
600 .refcnt = p->tcf_refcnt - ref,
601 .bindcnt = p->tcf_bindcnt - bind,
602 };
603 struct tcf_t t;
604
605 params = rtnl_dereference(p->params);
606 opt.action = params->action;
607 opt.update_flags = params->update_flags;
608
609 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
610 goto nla_put_failure;
611
612 tcf_tm_dump(&t, &p->tcf_tm);
613 if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
614 goto nla_put_failure;
615
616 return skb->len;
617
618nla_put_failure:
619 nlmsg_trim(skb, b);
620 return -1;
621}
622
623static void tcf_csum_cleanup(struct tc_action *a)
624{
625 struct tcf_csum *p = to_tcf_csum(a);
626 struct tcf_csum_params *params;
627
628 params = rcu_dereference_protected(p->params, 1);
629 if (params)
630 kfree_rcu(params, rcu);
631}
632
633static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
634 struct netlink_callback *cb, int type,
635 const struct tc_action_ops *ops,
636 struct netlink_ext_ack *extack)
637{
638 struct tc_action_net *tn = net_generic(net, csum_net_id);
639
640 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
641}
642
643static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index,
644 struct netlink_ext_ack *extack)
645{
646 struct tc_action_net *tn = net_generic(net, csum_net_id);
647
648 return tcf_idr_search(tn, a, index);
649}
650
651static struct tc_action_ops act_csum_ops = {
652 .kind = "csum",
653 .type = TCA_ACT_CSUM,
654 .owner = THIS_MODULE,
655 .act = tcf_csum,
656 .dump = tcf_csum_dump,
657 .init = tcf_csum_init,
658 .cleanup = tcf_csum_cleanup,
659 .walk = tcf_csum_walker,
660 .lookup = tcf_csum_search,
661 .size = sizeof(struct tcf_csum),
662};
663
664static __net_init int csum_init_net(struct net *net)
665{
666 struct tc_action_net *tn = net_generic(net, csum_net_id);
667
668 return tc_action_net_init(tn, &act_csum_ops);
669}
670
671static void __net_exit csum_exit_net(struct list_head *net_list)
672{
673 tc_action_net_exit(net_list, csum_net_id);
674}
675
676static struct pernet_operations csum_net_ops = {
677 .init = csum_init_net,
678 .exit_batch = csum_exit_net,
679 .id = &csum_net_id,
680 .size = sizeof(struct tc_action_net),
681};
682
683MODULE_DESCRIPTION("Checksum updating actions");
684MODULE_LICENSE("GPL");
685
686static int __init csum_init_module(void)
687{
688 return tcf_register_action(&act_csum_ops, &csum_net_ops);
689}
690
691static void __exit csum_cleanup_module(void)
692{
693 tcf_unregister_action(&act_csum_ops, &csum_net_ops);
694}
695
696module_init(csum_init_module);
697module_exit(csum_cleanup_module);