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 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) ||
125 skb_try_make_writable(skb, hl + ntkoff))
128 return (void *)(skb_network_header(skb) + ihl);
131 static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
132 unsigned int ihl, unsigned int ipl)
134 struct icmphdr *icmph;
136 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
141 skb->csum = csum_partial(icmph, ipl - ihl, 0);
142 icmph->checksum = csum_fold(skb->csum);
144 skb->ip_summed = CHECKSUM_NONE;
149 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
150 unsigned int ihl, unsigned int ipl)
152 struct igmphdr *igmph;
154 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
159 skb->csum = csum_partial(igmph, ipl - ihl, 0);
160 igmph->csum = csum_fold(skb->csum);
162 skb->ip_summed = CHECKSUM_NONE;
167 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
168 unsigned int ihl, unsigned int ipl)
170 struct icmp6hdr *icmp6h;
172 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
176 icmp6h->icmp6_cksum = 0;
177 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
178 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
179 ipl - ihl, IPPROTO_ICMPV6,
182 skb->ip_summed = CHECKSUM_NONE;
187 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
188 unsigned int ihl, unsigned int ipl)
192 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
197 skb->csum = csum_partial(tcph, ipl - ihl, 0);
198 tcph->check = tcp_v4_check(ipl - ihl,
199 iph->saddr, iph->daddr, skb->csum);
201 skb->ip_summed = CHECKSUM_NONE;
206 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
207 unsigned int ihl, unsigned int ipl)
211 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
216 skb->csum = csum_partial(tcph, ipl - ihl, 0);
217 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
218 ipl - ihl, IPPROTO_TCP,
221 skb->ip_summed = CHECKSUM_NONE;
226 static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
227 unsigned int ihl, unsigned int ipl, int udplite)
233 * Support both UDP and UDPLITE checksum algorithms, Don't use
234 * udph->len to get the real length without any protocol check,
235 * UDPLITE uses udph->len for another thing,
236 * Use iph->tot_len, or just ipl.
239 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
243 ul = ntohs(udph->len);
245 if (udplite || udph->check) {
251 skb->csum = csum_partial(udph, ipl - ihl, 0);
252 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
253 skb->csum = csum_partial(udph, ul, 0);
255 goto ignore_obscure_skb;
258 goto ignore_obscure_skb;
260 skb->csum = csum_partial(udph, ul, 0);
263 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
268 udph->check = CSUM_MANGLED_0;
271 skb->ip_summed = CHECKSUM_NONE;
277 static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
278 unsigned int ihl, unsigned int ipl, int udplite)
284 * Support both UDP and UDPLITE checksum algorithms, Don't use
285 * udph->len to get the real length without any protocol check,
286 * UDPLITE uses udph->len for another thing,
287 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
290 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
294 ul = ntohs(udph->len);
300 skb->csum = csum_partial(udph, ipl - ihl, 0);
302 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
303 skb->csum = csum_partial(udph, ul, 0);
306 goto ignore_obscure_skb;
309 goto ignore_obscure_skb;
311 skb->csum = csum_partial(udph, ul, 0);
314 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
315 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
319 udph->check = CSUM_MANGLED_0;
321 skb->ip_summed = CHECKSUM_NONE;
327 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
332 ntkoff = skb_network_offset(skb);
334 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
339 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
341 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
342 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
343 ntohs(iph->tot_len)))
347 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
348 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
349 ntohs(iph->tot_len)))
353 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
354 if (!tcf_csum_ipv4_tcp(skb, iph, iph->ihl * 4,
355 ntohs(iph->tot_len)))
359 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
360 if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
361 ntohs(iph->tot_len), 0))
364 case IPPROTO_UDPLITE:
365 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
366 if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
367 ntohs(iph->tot_len), 1))
372 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
373 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
385 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
386 unsigned int ixhl, unsigned int *pl)
388 int off, len, optlen;
389 unsigned char *xh = (void *)ip6xh;
391 off = sizeof(*ip6xh);
400 optlen = xh[off + 1] + 2;
401 if (optlen != 6 || len < 6 || (off & 3) != 2)
402 /* wrong jumbo option length/alignment */
404 *pl = ntohl(*(__be32 *)(xh + off + 2));
407 optlen = xh[off + 1] + 2;
409 /* ignore obscure options */
421 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
423 struct ipv6hdr *ip6h;
424 struct ipv6_opt_hdr *ip6xh;
425 unsigned int hl, ixhl;
430 ntkoff = skb_network_offset(skb);
434 if (!pskb_may_pull(skb, hl + ntkoff))
437 ip6h = ipv6_hdr(skb);
439 pl = ntohs(ip6h->payload_len);
440 nexthdr = ip6h->nexthdr;
444 case NEXTHDR_FRAGMENT:
446 case NEXTHDR_ROUTING:
449 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
451 ip6xh = (void *)(skb_network_header(skb) + hl);
452 ixhl = ipv6_optlen(ip6xh);
453 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
455 if ((nexthdr == NEXTHDR_HOP) &&
456 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
458 nexthdr = ip6xh->nexthdr;
462 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
463 if (!tcf_csum_ipv6_icmp(skb, ip6h,
464 hl, pl + sizeof(*ip6h)))
468 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
469 if (!tcf_csum_ipv6_tcp(skb, ip6h,
470 hl, pl + sizeof(*ip6h)))
474 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
475 if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
476 pl + sizeof(*ip6h), 0))
479 case IPPROTO_UDPLITE:
480 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
481 if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
482 pl + sizeof(*ip6h), 1))
488 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
498 static int tcf_csum(struct sk_buff *skb,
499 const struct tc_action *a, struct tcf_result *res)
501 struct tcf_csum *p = a->priv;
505 spin_lock(&p->tcf_lock);
506 p->tcf_tm.lastuse = jiffies;
507 bstats_update(&p->tcf_bstats, skb);
508 action = p->tcf_action;
509 update_flags = p->update_flags;
510 spin_unlock(&p->tcf_lock);
512 if (unlikely(action == TC_ACT_SHOT))
515 switch (skb->protocol) {
516 case cpu_to_be16(ETH_P_IP):
517 if (!tcf_csum_ipv4(skb, update_flags))
520 case cpu_to_be16(ETH_P_IPV6):
521 if (!tcf_csum_ipv6(skb, update_flags))
529 spin_lock(&p->tcf_lock);
530 p->tcf_qstats.drops++;
531 spin_unlock(&p->tcf_lock);
535 static int tcf_csum_dump(struct sk_buff *skb,
536 struct tc_action *a, int bind, int ref)
538 unsigned char *b = skb_tail_pointer(skb);
539 struct tcf_csum *p = a->priv;
540 struct tc_csum opt = {
541 .update_flags = p->update_flags,
542 .index = p->tcf_index,
543 .action = p->tcf_action,
544 .refcnt = p->tcf_refcnt - ref,
545 .bindcnt = p->tcf_bindcnt - bind,
549 NLA_PUT(skb, TCA_CSUM_PARMS, sizeof(opt), &opt);
550 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
551 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
552 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
553 NLA_PUT(skb, TCA_CSUM_TM, sizeof(t), &t);
562 static struct tc_action_ops act_csum_ops = {
564 .hinfo = &csum_hash_info,
565 .type = TCA_ACT_CSUM,
566 .capab = TCA_CAP_NONE,
567 .owner = THIS_MODULE,
569 .dump = tcf_csum_dump,
570 .cleanup = tcf_csum_cleanup,
571 .lookup = tcf_hash_search,
572 .init = tcf_csum_init,
573 .walk = tcf_generic_walker
576 MODULE_DESCRIPTION("Checksum updating actions");
577 MODULE_LICENSE("GPL");
579 static int __init csum_init_module(void)
581 return tcf_register_action(&act_csum_ops);
584 static void __exit csum_cleanup_module(void)
586 tcf_unregister_action(&act_csum_ops);
589 module_init(csum_init_module);
590 module_exit(csum_cleanup_module);