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
41 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
42 [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
45 static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
46 struct tc_action *a, int ovr, int bind)
48 struct nlattr *tb[TCA_CSUM_MAX + 1];
56 err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
60 if (tb[TCA_CSUM_PARMS] == NULL)
62 parm = nla_data(tb[TCA_CSUM_PARMS]);
64 if (!tcf_hash_check(parm->index, a, bind)) {
65 ret = tcf_hash_create(parm->index, est, a, sizeof(*p),
71 if (bind)/* dont override defaults */
73 tcf_hash_release(a, bind);
79 spin_lock_bh(&p->tcf_lock);
80 p->tcf_action = parm->action;
81 p->update_flags = parm->update_flags;
82 spin_unlock_bh(&p->tcf_lock);
84 if (ret == ACT_P_CREATED)
91 * tcf_csum_skb_nextlayer - Get next layer pointer
92 * @skb: sk_buff to use
93 * @ihl: previous summed headers length
94 * @ipl: complete packet length
95 * @jhl: next header length
97 * Check the expected next layer availability in the specified sk_buff.
98 * Return the next layer pointer if pass, NULL otherwise.
100 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
101 unsigned int ihl, unsigned int ipl,
104 int ntkoff = skb_network_offset(skb);
107 if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
108 skb_try_make_writable(skb, hl + ntkoff))
111 return (void *)(skb_network_header(skb) + ihl);
114 static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
115 unsigned int ihl, unsigned int ipl)
117 struct icmphdr *icmph;
119 icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
124 skb->csum = csum_partial(icmph, ipl - ihl, 0);
125 icmph->checksum = csum_fold(skb->csum);
127 skb->ip_summed = CHECKSUM_NONE;
132 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
133 unsigned int ihl, unsigned int ipl)
135 struct igmphdr *igmph;
137 igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
142 skb->csum = csum_partial(igmph, ipl - ihl, 0);
143 igmph->csum = csum_fold(skb->csum);
145 skb->ip_summed = CHECKSUM_NONE;
150 static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
151 unsigned int ihl, unsigned int ipl)
153 struct icmp6hdr *icmp6h;
154 const struct ipv6hdr *ip6h;
156 icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
160 ip6h = ipv6_hdr(skb);
161 icmp6h->icmp6_cksum = 0;
162 skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
163 icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
164 ipl - ihl, IPPROTO_ICMPV6,
167 skb->ip_summed = CHECKSUM_NONE;
172 static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
173 unsigned int ihl, unsigned int ipl)
176 const struct iphdr *iph;
178 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
184 skb->csum = csum_partial(tcph, ipl - ihl, 0);
185 tcph->check = tcp_v4_check(ipl - ihl,
186 iph->saddr, iph->daddr, skb->csum);
188 skb->ip_summed = CHECKSUM_NONE;
193 static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
194 unsigned int ihl, unsigned int ipl)
197 const struct ipv6hdr *ip6h;
199 tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
203 ip6h = ipv6_hdr(skb);
205 skb->csum = csum_partial(tcph, ipl - ihl, 0);
206 tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
207 ipl - ihl, IPPROTO_TCP,
210 skb->ip_summed = CHECKSUM_NONE;
215 static int tcf_csum_ipv4_udp(struct sk_buff *skb,
216 unsigned int ihl, unsigned int ipl, int udplite)
219 const struct iphdr *iph;
223 * Support both UDP and UDPLITE checksum algorithms, Don't use
224 * udph->len to get the real length without any protocol check,
225 * UDPLITE uses udph->len for another thing,
226 * Use iph->tot_len, or just ipl.
229 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
234 ul = ntohs(udph->len);
236 if (udplite || udph->check) {
242 skb->csum = csum_partial(udph, ipl - ihl, 0);
243 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
244 skb->csum = csum_partial(udph, ul, 0);
246 goto ignore_obscure_skb;
249 goto ignore_obscure_skb;
251 skb->csum = csum_partial(udph, ul, 0);
254 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
259 udph->check = CSUM_MANGLED_0;
262 skb->ip_summed = CHECKSUM_NONE;
268 static int tcf_csum_ipv6_udp(struct sk_buff *skb,
269 unsigned int ihl, unsigned int ipl, int udplite)
272 const struct ipv6hdr *ip6h;
276 * Support both UDP and UDPLITE checksum algorithms, Don't use
277 * udph->len to get the real length without any protocol check,
278 * UDPLITE uses udph->len for another thing,
279 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
282 udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
286 ip6h = ipv6_hdr(skb);
287 ul = ntohs(udph->len);
293 skb->csum = csum_partial(udph, ipl - ihl, 0);
295 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
296 skb->csum = csum_partial(udph, ul, 0);
299 goto ignore_obscure_skb;
302 goto ignore_obscure_skb;
304 skb->csum = csum_partial(udph, ul, 0);
307 udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
308 udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
312 udph->check = CSUM_MANGLED_0;
314 skb->ip_summed = CHECKSUM_NONE;
320 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
322 const struct iphdr *iph;
325 ntkoff = skb_network_offset(skb);
327 if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
332 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
334 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
335 if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
336 ntohs(iph->tot_len)))
340 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
341 if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
342 ntohs(iph->tot_len)))
346 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
347 if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
348 ntohs(iph->tot_len)))
352 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
353 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
354 ntohs(iph->tot_len), 0))
357 case IPPROTO_UDPLITE:
358 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
359 if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
360 ntohs(iph->tot_len), 1))
365 if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
366 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
369 ip_send_check(ip_hdr(skb));
378 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
379 unsigned int ixhl, unsigned int *pl)
381 int off, len, optlen;
382 unsigned char *xh = (void *)ip6xh;
384 off = sizeof(*ip6xh);
393 optlen = xh[off + 1] + 2;
394 if (optlen != 6 || len < 6 || (off & 3) != 2)
395 /* wrong jumbo option length/alignment */
397 *pl = ntohl(*(__be32 *)(xh + off + 2));
400 optlen = xh[off + 1] + 2;
402 /* ignore obscure options */
414 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
416 struct ipv6hdr *ip6h;
417 struct ipv6_opt_hdr *ip6xh;
418 unsigned int hl, ixhl;
423 ntkoff = skb_network_offset(skb);
427 if (!pskb_may_pull(skb, hl + ntkoff))
430 ip6h = ipv6_hdr(skb);
432 pl = ntohs(ip6h->payload_len);
433 nexthdr = ip6h->nexthdr;
437 case NEXTHDR_FRAGMENT:
439 case NEXTHDR_ROUTING:
442 if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
444 ip6xh = (void *)(skb_network_header(skb) + hl);
445 ixhl = ipv6_optlen(ip6xh);
446 if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
448 ip6xh = (void *)(skb_network_header(skb) + hl);
449 if ((nexthdr == NEXTHDR_HOP) &&
450 !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
452 nexthdr = ip6xh->nexthdr;
456 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
457 if (!tcf_csum_ipv6_icmp(skb,
458 hl, pl + sizeof(*ip6h)))
462 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
463 if (!tcf_csum_ipv6_tcp(skb,
464 hl, pl + sizeof(*ip6h)))
468 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
469 if (!tcf_csum_ipv6_udp(skb, hl,
470 pl + sizeof(*ip6h), 0))
473 case IPPROTO_UDPLITE:
474 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
475 if (!tcf_csum_ipv6_udp(skb, hl,
476 pl + sizeof(*ip6h), 1))
482 } while (pskb_may_pull(skb, hl + 1 + ntkoff));
492 static int tcf_csum(struct sk_buff *skb,
493 const struct tc_action *a, struct tcf_result *res)
495 struct tcf_csum *p = a->priv;
499 spin_lock(&p->tcf_lock);
500 p->tcf_tm.lastuse = jiffies;
501 bstats_update(&p->tcf_bstats, skb);
502 action = p->tcf_action;
503 update_flags = p->update_flags;
504 spin_unlock(&p->tcf_lock);
506 if (unlikely(action == TC_ACT_SHOT))
509 switch (tc_skb_protocol(skb)) {
510 case cpu_to_be16(ETH_P_IP):
511 if (!tcf_csum_ipv4(skb, update_flags))
514 case cpu_to_be16(ETH_P_IPV6):
515 if (!tcf_csum_ipv6(skb, update_flags))
523 spin_lock(&p->tcf_lock);
524 p->tcf_qstats.drops++;
525 spin_unlock(&p->tcf_lock);
529 static int tcf_csum_dump(struct sk_buff *skb,
530 struct tc_action *a, int bind, int ref)
532 unsigned char *b = skb_tail_pointer(skb);
533 struct tcf_csum *p = a->priv;
534 struct tc_csum opt = {
535 .update_flags = p->update_flags,
536 .index = p->tcf_index,
537 .action = p->tcf_action,
538 .refcnt = p->tcf_refcnt - ref,
539 .bindcnt = p->tcf_bindcnt - bind,
543 if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
544 goto nla_put_failure;
545 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
546 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
547 t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
548 if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
549 goto nla_put_failure;
558 static struct tc_action_ops act_csum_ops = {
560 .type = TCA_ACT_CSUM,
561 .owner = THIS_MODULE,
563 .dump = tcf_csum_dump,
564 .init = tcf_csum_init,
567 MODULE_DESCRIPTION("Checksum updating actions");
568 MODULE_LICENSE("GPL");
570 static int __init csum_init_module(void)
572 return tcf_register_action(&act_csum_ops, CSUM_TAB_MASK);
575 static void __exit csum_cleanup_module(void)
577 tcf_unregister_action(&act_csum_ops);
580 module_init(csum_init_module);
581 module_exit(csum_cleanup_module);