2 * Checksum updating actions
4 * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
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)
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>
19 #include <linux/netlink.h>
20 #include <net/netlink.h>
21 #include <linux/rtnetlink.h>
23 #include <linux/skbuff.h>
28 #include <linux/icmpv6.h>
29 #include <linux/igmp.h>
32 #include <net/ip6_checksum.h>
34 #include <net/act_api.h>
36 #include <linux/tc_act/tc_csum.h>
37 #include <net/tc_act/tc_csum.h>
39 #define CSUM_TAB_MASK 15
40 static struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
41 static u32 csum_idx_gen;
42 static DEFINE_RWLOCK(csum_lock);
44 static struct tcf_hashinfo csum_hash_info = {
46 .hmask = CSUM_TAB_MASK,
50 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
51 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
54 static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
55 struct tc_action *a, int ovr, int bind)
57 struct nlattr *tb[TCA_CSUM_MAX + 1];
59 struct tcf_common *pc;
66 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
70 if (tb[TCA_CSUM_PARMS] == NULL)
72 parm = nla_data(tb[TCA_CSUM_PARMS]);
74 pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
76 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
77 &csum_idx_gen, &csum_hash_info);
85 tcf_hash_release(pc, bind, &csum_hash_info);
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);
95 if (ret == ACT_P_CREATED)
96 tcf_hash_insert(pc, &csum_hash_info);
101 static int tcf_csum_cleanup(struct tc_action *a, int bind)
103 struct tcf_csum *p = a->priv;
104 return tcf_hash_release(&p->common, bind, &csum_hash_info);
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
114 * Check the expected next layer availability in the specified sk_buff.
115 * Return the next layer pointer if pass, NULL otherwise.
117 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
118 unsigned int ihl, unsigned int ipl,
121 int ntkoff = skb_network_offset(skb);
124 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
126 !skb_clone_writable(skb, hl + ntkoff) &&
127 pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
130 return (void *)(skb_network_header(skb) + ihl);
133 static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
134 unsigned int ihl, unsigned int ipl)
136 struct icmphdr *icmph;
138 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
143 skb->csum = csum_partial(icmph, ipl - ihl, 0);
144 icmph->checksum = csum_fold(skb->csum);
146 skb->ip_summed = CHECKSUM_NONE;
151 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
152 unsigned int ihl, unsigned int ipl)
154 struct igmphdr *igmph;
156 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
161 skb->csum = csum_partial(igmph, ipl - ihl, 0);
162 igmph->csum = csum_fold(skb->csum);
164 skb->ip_summed = CHECKSUM_NONE;
169 static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
170 unsigned int ihl, unsigned int ipl)
172 struct icmp6hdr *icmp6h;
173 const struct ipv6hdr *ip6h;
175 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
179 ip6h = ipv6_hdr(skb);
180 icmp6h->icmp6_cksum = 0;
181 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
182 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
183 ipl - ihl, IPPROTO_ICMPV6,
186 skb->ip_summed = CHECKSUM_NONE;
191 static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
192 unsigned int ihl, unsigned int ipl)
195 const struct iphdr *iph;
197 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
203 skb->csum = csum_partial(tcph, ipl - ihl, 0);
204 tcph->check = tcp_v4_check(ipl - ihl,
205 iph->saddr, iph->daddr, skb->csum);
207 skb->ip_summed = CHECKSUM_NONE;
212 static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
213 unsigned int ihl, unsigned int ipl)
216 const struct ipv6hdr *ip6h;
218 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
222 ip6h = ipv6_hdr(skb);
224 skb->csum = csum_partial(tcph, ipl - ihl, 0);
225 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
226 ipl - ihl, IPPROTO_TCP,
229 skb->ip_summed = CHECKSUM_NONE;
234 static int tcf_csum_ipv4_udp(struct sk_buff *skb,
235 unsigned int ihl, unsigned int ipl, int udplite)
238 const struct iphdr *iph;
242 * Support both UDP and UDPLITE checksum algorithms, Don't use
243 * udph->len to get the real length without any protocol check,
244 * UDPLITE uses udph->len for another thing,
245 * Use iph->tot_len, or just ipl.
248 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
253 ul = ntohs(udph->len);
255 if (udplite || udph->check) {
261 skb->csum = csum_partial(udph, ipl - ihl, 0);
262 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
263 skb->csum = csum_partial(udph, ul, 0);
265 goto ignore_obscure_skb;
268 goto ignore_obscure_skb;
270 skb->csum = csum_partial(udph, ul, 0);
273 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
278 udph->check = CSUM_MANGLED_0;
281 skb->ip_summed = CHECKSUM_NONE;
287 static int tcf_csum_ipv6_udp(struct sk_buff *skb,
288 unsigned int ihl, unsigned int ipl, int udplite)
291 const struct ipv6hdr *ip6h;
295 * Support both UDP and UDPLITE checksum algorithms, Don't use
296 * udph->len to get the real length without any protocol check,
297 * UDPLITE uses udph->len for another thing,
298 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
301 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
305 ip6h = ipv6_hdr(skb);
306 ul = ntohs(udph->len);
312 skb->csum = csum_partial(udph, ipl - ihl, 0);
314 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
315 skb->csum = csum_partial(udph, ul, 0);
318 goto ignore_obscure_skb;
321 goto ignore_obscure_skb;
323 skb->csum = csum_partial(udph, ul, 0);
326 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
327 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
331 udph->check = CSUM_MANGLED_0;
333 skb->ip_summed = CHECKSUM_NONE;
339 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
341 const struct iphdr *iph;
344 ntkoff = skb_network_offset(skb);
346 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
351 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
353 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
354 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
355 ntohs(iph->tot_len)))
359 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
360 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
361 ntohs(iph->tot_len)))
365 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
366 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
367 ntohs(iph->tot_len)))
371 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
372 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
373 ntohs(iph->tot_len), 0))
376 case IPPROTO_UDPLITE:
377 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
378 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
379 ntohs(iph->tot_len), 1))
384 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
385 if (skb_cloned(skb) &&
386 !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
387 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
390 ip_send_check(ip_hdr(skb));
399 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
400 unsigned int ixhl, unsigned int *pl)
402 int off, len, optlen;
403 unsigned char *xh = (void *)ip6xh;
405 off = sizeof(*ip6xh);
414 optlen = xh[off + 1] + 2;
415 if (optlen != 6 || len < 6 || (off & 3) != 2)
416 /* wrong jumbo option length/alignment */
418 *pl = ntohl(*(__be32 *)(xh + off + 2));
421 optlen = xh[off + 1] + 2;
423 /* ignore obscure options */
435 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
437 struct ipv6hdr *ip6h;
438 struct ipv6_opt_hdr *ip6xh;
439 unsigned int hl, ixhl;
444 ntkoff = skb_network_offset(skb);
448 if (!pskb_may_pull(skb, hl + ntkoff))
451 ip6h = ipv6_hdr(skb);
453 pl = ntohs(ip6h->payload_len);
454 nexthdr = ip6h->nexthdr;
458 case NEXTHDR_FRAGMENT:
460 case NEXTHDR_ROUTING:
463 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
465 ip6xh = (void *)(skb_network_header(skb) + hl);
466 ixhl = ipv6_optlen(ip6xh);
467 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
469 ip6xh = (void *)(skb_network_header(skb) + hl);
470 if ((nexthdr == NEXTHDR_HOP) &&
471 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
473 nexthdr = ip6xh->nexthdr;
477 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
478 if (!tcf_csum_ipv6_icmp(skb,
479 hl, pl + sizeof(*ip6h)))
483 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
484 if (!tcf_csum_ipv6_tcp(skb,
485 hl, pl + sizeof(*ip6h)))
489 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
490 if (!tcf_csum_ipv6_udp(skb, hl,
491 pl + sizeof(*ip6h), 0))
494 case IPPROTO_UDPLITE:
495 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
496 if (!tcf_csum_ipv6_udp(skb, hl,
497 pl + sizeof(*ip6h), 1))
503 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
513 static int tcf_csum(struct sk_buff *skb,
514 const struct tc_action *a, struct tcf_result *res)
516 struct tcf_csum *p = a->priv;
520 spin_lock(&p->tcf_lock);
521 p->tcf_tm.lastuse = jiffies;
522 bstats_update(&p->tcf_bstats, skb);
523 action = p->tcf_action;
524 update_flags = p->update_flags;
525 spin_unlock(&p->tcf_lock);
527 if (unlikely(action == TC_ACT_SHOT))
530 switch (skb->protocol) {
531 case cpu_to_be16(ETH_P_IP):
532 if (!tcf_csum_ipv4(skb, update_flags))
535 case cpu_to_be16(ETH_P_IPV6):
536 if (!tcf_csum_ipv6(skb, update_flags))
544 spin_lock(&p->tcf_lock);
545 p->tcf_qstats.drops++;
546 spin_unlock(&p->tcf_lock);
550 static int tcf_csum_dump(struct sk_buff *skb,
551 struct tc_action *a, int bind, int ref)
553 unsigned char *b = skb_tail_pointer(skb);
554 struct tcf_csum *p = a->priv;
555 struct tc_csum opt = {
556 .update_flags = p->update_flags,
557 .index = p->tcf_index,
558 .action = p->tcf_action,
559 .refcnt = p->tcf_refcnt - ref,
560 .bindcnt = p->tcf_bindcnt - bind,
564 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
565 goto nla_put_failure;
566 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
567 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
568 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
569 if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
570 goto nla_put_failure;
579 static struct tc_action_ops act_csum_ops = {
581 .hinfo = &csum_hash_info,
582 .type = TCA_ACT_CSUM,
583 .capab = TCA_CAP_NONE,
584 .owner = THIS_MODULE,
586 .dump = tcf_csum_dump,
587 .cleanup = tcf_csum_cleanup,
588 .lookup = tcf_hash_search,
589 .init = tcf_csum_init,
590 .walk = tcf_generic_walker
593 MODULE_DESCRIPTION("Checksum updating actions");
594 MODULE_LICENSE("GPL");
596 static int __init csum_init_module(void)
598 return tcf_register_action(&act_csum_ops);
601 static void __exit csum_cleanup_module(void)
603 tcf_unregister_action(&act_csum_ops);
606 module_init(csum_init_module);
607 module_exit(csum_cleanup_module);