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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 tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
46 struct tc_action *a, int ovr, int bind)
47{
48 struct nlattr *tb[TCA_CSUM_MAX + 1];
49 struct tc_csum *parm;
50 struct tcf_csum *p;
51 int ret = 0, err;
52
53 if (nla == NULL)
54 return -EINVAL;
55
56 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
57 if (err < 0)
58 return err;
59
60 if (tb[TCA_CSUM_PARMS] == NULL)
61 return -EINVAL;
62 parm = nla_data(tb[TCA_CSUM_PARMS]);
63
64 if (!tcf_hash_check(parm->index, a, bind)) {
65 ret = tcf_hash_create(parm->index, est, a, sizeof(*p), bind);
66 if (ret)
67 return ret;
68 ret = ACT_P_CREATED;
69 } else {
70 if (bind)
71 return 0;
72 tcf_hash_release(a, bind);
73 if (!ovr)
74 return -EEXIST;
75 }
76
77 p = to_tcf_csum(a);
78 spin_lock_bh(&p->tcf_lock);
79 p->tcf_action = parm->action;
80 p->update_flags = parm->update_flags;
81 spin_unlock_bh(&p->tcf_lock);
82
83 if (ret == ACT_P_CREATED)
84 tcf_hash_insert(a);
85
86 return ret;
87}
88
89
90
91
92
93
94
95
96
97
98
99static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
100 unsigned int ihl, unsigned int ipl,
101 unsigned int jhl)
102{
103 int ntkoff = skb_network_offset(skb);
104 int hl = ihl + jhl;
105
106 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
107 (skb_cloned(skb) &&
108 !skb_clone_writable(skb, hl + ntkoff) &&
109 pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
110 return NULL;
111 else
112 return (void *)(skb_network_header(skb) + ihl);
113}
114
115static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
116 unsigned int ihl, unsigned int ipl)
117{
118 struct icmphdr *icmph;
119
120 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
121 if (icmph == NULL)
122 return 0;
123
124 icmph->checksum = 0;
125 skb->csum = csum_partial(icmph, ipl - ihl, 0);
126 icmph->checksum = csum_fold(skb->csum);
127
128 skb->ip_summed = CHECKSUM_NONE;
129
130 return 1;
131}
132
133static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
134 unsigned int ihl, unsigned int ipl)
135{
136 struct igmphdr *igmph;
137
138 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
139 if (igmph == NULL)
140 return 0;
141
142 igmph->csum = 0;
143 skb->csum = csum_partial(igmph, ipl - ihl, 0);
144 igmph->csum = csum_fold(skb->csum);
145
146 skb->ip_summed = CHECKSUM_NONE;
147
148 return 1;
149}
150
151static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
152 unsigned int ihl, unsigned int ipl)
153{
154 struct icmp6hdr *icmp6h;
155 const struct ipv6hdr *ip6h;
156
157 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
158 if (icmp6h == NULL)
159 return 0;
160
161 ip6h = ipv6_hdr(skb);
162 icmp6h->icmp6_cksum = 0;
163 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
164 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
165 ipl - ihl, IPPROTO_ICMPV6,
166 skb->csum);
167
168 skb->ip_summed = CHECKSUM_NONE;
169
170 return 1;
171}
172
173static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
174 unsigned int ihl, unsigned int ipl)
175{
176 struct tcphdr *tcph;
177 const struct iphdr *iph;
178
179 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
180 if (tcph == NULL)
181 return 0;
182
183 iph = ip_hdr(skb);
184 tcph->check = 0;
185 skb->csum = csum_partial(tcph, ipl - ihl, 0);
186 tcph->check = tcp_v4_check(ipl - ihl,
187 iph->saddr, iph->daddr, skb->csum);
188
189 skb->ip_summed = CHECKSUM_NONE;
190
191 return 1;
192}
193
194static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
195 unsigned int ihl, unsigned int ipl)
196{
197 struct tcphdr *tcph;
198 const struct ipv6hdr *ip6h;
199
200 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
201 if (tcph == NULL)
202 return 0;
203
204 ip6h = ipv6_hdr(skb);
205 tcph->check = 0;
206 skb->csum = csum_partial(tcph, ipl - ihl, 0);
207 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
208 ipl - ihl, IPPROTO_TCP,
209 skb->csum);
210
211 skb->ip_summed = CHECKSUM_NONE;
212
213 return 1;
214}
215
216static int tcf_csum_ipv4_udp(struct sk_buff *skb,
217 unsigned int ihl, unsigned int ipl, int udplite)
218{
219 struct udphdr *udph;
220 const struct iphdr *iph;
221 u16 ul;
222
223
224
225
226
227
228
229
230 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
231 if (udph == NULL)
232 return 0;
233
234 iph = ip_hdr(skb);
235 ul = ntohs(udph->len);
236
237 if (udplite || udph->check) {
238
239 udph->check = 0;
240
241 if (udplite) {
242 if (ul == 0)
243 skb->csum = csum_partial(udph, ipl - ihl, 0);
244 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
245 skb->csum = csum_partial(udph, ul, 0);
246 else
247 goto ignore_obscure_skb;
248 } else {
249 if (ul != ipl - ihl)
250 goto ignore_obscure_skb;
251
252 skb->csum = csum_partial(udph, ul, 0);
253 }
254
255 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
256 ul, iph->protocol,
257 skb->csum);
258
259 if (!udph->check)
260 udph->check = CSUM_MANGLED_0;
261 }
262
263 skb->ip_summed = CHECKSUM_NONE;
264
265ignore_obscure_skb:
266 return 1;
267}
268
269static int tcf_csum_ipv6_udp(struct sk_buff *skb,
270 unsigned int ihl, unsigned int ipl, int udplite)
271{
272 struct udphdr *udph;
273 const struct ipv6hdr *ip6h;
274 u16 ul;
275
276
277
278
279
280
281
282
283 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
284 if (udph == NULL)
285 return 0;
286
287 ip6h = ipv6_hdr(skb);
288 ul = ntohs(udph->len);
289
290 udph->check = 0;
291
292 if (udplite) {
293 if (ul == 0)
294 skb->csum = csum_partial(udph, ipl - ihl, 0);
295
296 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
297 skb->csum = csum_partial(udph, ul, 0);
298
299 else
300 goto ignore_obscure_skb;
301 } else {
302 if (ul != ipl - ihl)
303 goto ignore_obscure_skb;
304
305 skb->csum = csum_partial(udph, ul, 0);
306 }
307
308 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
309 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
310 skb->csum);
311
312 if (!udph->check)
313 udph->check = CSUM_MANGLED_0;
314
315 skb->ip_summed = CHECKSUM_NONE;
316
317ignore_obscure_skb:
318 return 1;
319}
320
321static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
322{
323 const struct iphdr *iph;
324 int ntkoff;
325
326 ntkoff = skb_network_offset(skb);
327
328 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
329 goto fail;
330
331 iph = ip_hdr(skb);
332
333 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
334 case IPPROTO_ICMP:
335 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
336 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
337 ntohs(iph->tot_len)))
338 goto fail;
339 break;
340 case IPPROTO_IGMP:
341 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
342 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
343 ntohs(iph->tot_len)))
344 goto fail;
345 break;
346 case IPPROTO_TCP:
347 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
348 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
349 ntohs(iph->tot_len)))
350 goto fail;
351 break;
352 case IPPROTO_UDP:
353 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
354 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
355 ntohs(iph->tot_len), 0))
356 goto fail;
357 break;
358 case IPPROTO_UDPLITE:
359 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
360 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
361 ntohs(iph->tot_len), 1))
362 goto fail;
363 break;
364 }
365
366 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
367 if (skb_cloned(skb) &&
368 !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
369 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
370 goto fail;
371
372 ip_send_check(ip_hdr(skb));
373 }
374
375 return 1;
376
377fail:
378 return 0;
379}
380
381static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
382 unsigned int ixhl, unsigned int *pl)
383{
384 int off, len, optlen;
385 unsigned char *xh = (void *)ip6xh;
386
387 off = sizeof(*ip6xh);
388 len = ixhl - off;
389
390 while (len > 1) {
391 switch (xh[off]) {
392 case IPV6_TLV_PAD1:
393 optlen = 1;
394 break;
395 case IPV6_TLV_JUMBO:
396 optlen = xh[off + 1] + 2;
397 if (optlen != 6 || len < 6 || (off & 3) != 2)
398
399 return 0;
400 *pl = ntohl(*(__be32 *)(xh + off + 2));
401 goto done;
402 default:
403 optlen = xh[off + 1] + 2;
404 if (optlen > len)
405
406 goto done;
407 break;
408 }
409 off += optlen;
410 len -= optlen;
411 }
412
413done:
414 return 1;
415}
416
417static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
418{
419 struct ipv6hdr *ip6h;
420 struct ipv6_opt_hdr *ip6xh;
421 unsigned int hl, ixhl;
422 unsigned int pl;
423 int ntkoff;
424 u8 nexthdr;
425
426 ntkoff = skb_network_offset(skb);
427
428 hl = sizeof(*ip6h);
429
430 if (!pskb_may_pull(skb, hl + ntkoff))
431 goto fail;
432
433 ip6h = ipv6_hdr(skb);
434
435 pl = ntohs(ip6h->payload_len);
436 nexthdr = ip6h->nexthdr;
437
438 do {
439 switch (nexthdr) {
440 case NEXTHDR_FRAGMENT:
441 goto ignore_skb;
442 case NEXTHDR_ROUTING:
443 case NEXTHDR_HOP:
444 case NEXTHDR_DEST:
445 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
446 goto fail;
447 ip6xh = (void *)(skb_network_header(skb) + hl);
448 ixhl = ipv6_optlen(ip6xh);
449 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
450 goto fail;
451 ip6xh = (void *)(skb_network_header(skb) + hl);
452 if ((nexthdr == NEXTHDR_HOP) &&
453 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
454 goto fail;
455 nexthdr = ip6xh->nexthdr;
456 hl += ixhl;
457 break;
458 case IPPROTO_ICMPV6:
459 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
460 if (!tcf_csum_ipv6_icmp(skb,
461 hl, pl + sizeof(*ip6h)))
462 goto fail;
463 goto done;
464 case IPPROTO_TCP:
465 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
466 if (!tcf_csum_ipv6_tcp(skb,
467 hl, pl + sizeof(*ip6h)))
468 goto fail;
469 goto done;
470 case IPPROTO_UDP:
471 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
472 if (!tcf_csum_ipv6_udp(skb, hl,
473 pl + sizeof(*ip6h), 0))
474 goto fail;
475 goto done;
476 case IPPROTO_UDPLITE:
477 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
478 if (!tcf_csum_ipv6_udp(skb, hl,
479 pl + sizeof(*ip6h), 1))
480 goto fail;
481 goto done;
482 default:
483 goto ignore_skb;
484 }
485 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
486
487done:
488ignore_skb:
489 return 1;
490
491fail:
492 return 0;
493}
494
495static int tcf_csum(struct sk_buff *skb,
496 const struct tc_action *a, struct tcf_result *res)
497{
498 struct tcf_csum *p = a->priv;
499 int action;
500 u32 update_flags;
501
502 spin_lock(&p->tcf_lock);
503 p->tcf_tm.lastuse = jiffies;
504 bstats_update(&p->tcf_bstats, skb);
505 action = p->tcf_action;
506 update_flags = p->update_flags;
507 spin_unlock(&p->tcf_lock);
508
509 if (unlikely(action == TC_ACT_SHOT))
510 goto drop;
511
512 switch (tc_skb_protocol(skb)) {
513 case cpu_to_be16(ETH_P_IP):
514 if (!tcf_csum_ipv4(skb, update_flags))
515 goto drop;
516 break;
517 case cpu_to_be16(ETH_P_IPV6):
518 if (!tcf_csum_ipv6(skb, update_flags))
519 goto drop;
520 break;
521 }
522
523 return action;
524
525drop:
526 spin_lock(&p->tcf_lock);
527 p->tcf_qstats.drops++;
528 spin_unlock(&p->tcf_lock);
529 return TC_ACT_SHOT;
530}
531
532static int tcf_csum_dump(struct sk_buff *skb,
533 struct tc_action *a, int bind, int ref)
534{
535 unsigned char *b = skb_tail_pointer(skb);
536 struct tcf_csum *p = a->priv;
537 struct tc_csum opt = {
538 .update_flags = p->update_flags,
539 .index = p->tcf_index,
540 .action = p->tcf_action,
541 .refcnt = p->tcf_refcnt - ref,
542 .bindcnt = p->tcf_bindcnt - bind,
543 };
544 struct tcf_t t;
545
546 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
547 goto nla_put_failure;
548 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
549 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
550 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
551 if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
552 goto nla_put_failure;
553
554 return skb->len;
555
556nla_put_failure:
557 nlmsg_trim(skb, b);
558 return -1;
559}
560
561static struct tc_action_ops act_csum_ops = {
562 .kind = "csum",
563 .type = TCA_ACT_CSUM,
564 .owner = THIS_MODULE,
565 .act = tcf_csum,
566 .dump = tcf_csum_dump,
567 .init = tcf_csum_init,
568};
569
570MODULE_DESCRIPTION("Checksum updating actions");
571MODULE_LICENSE("GPL");
572
573static int __init csum_init_module(void)
574{
575 return tcf_register_action(&act_csum_ops, CSUM_TAB_MASK);
576}
577
578static void __exit csum_cleanup_module(void)
579{
580 tcf_unregister_action(&act_csum_ops);
581}
582
583module_init(csum_init_module);
584module_exit(csum_cleanup_module);
585
