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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;
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)
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
97
98
99
100
101
102
103
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
229
230
231
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
282
283
284
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
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
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);
626
