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- /*
- * Checksum updating actions
- *
- * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 2 of the License, or (at your option)
- * any later version.
- *
- */
- #include <linux/types.h>
- #include <linux/init.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/spinlock.h>
- #include <linux/netlink.h>
- #include <net/netlink.h>
- #include <linux/rtnetlink.h>
- #include <linux/skbuff.h>
- #include <net/ip.h>
- #include <net/ipv6.h>
- #include <net/icmp.h>
- #include <linux/icmpv6.h>
- #include <linux/igmp.h>
- #include <net/tcp.h>
- #include <net/udp.h>
- #include <net/ip6_checksum.h>
- #include <net/act_api.h>
- #include <linux/tc_act/tc_csum.h>
- #include <net/tc_act/tc_csum.h>
- #define CSUM_TAB_MASK 15
- static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
- [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
- };
- static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
- struct tc_action *a, int ovr, int bind)
- {
- struct nlattr *tb[TCA_CSUM_MAX + 1];
- struct tc_csum *parm;
- struct tcf_csum *p;
- int ret = 0, err;
- if (nla == NULL)
- return -EINVAL;
- err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
- if (err < 0)
- return err;
- if (tb[TCA_CSUM_PARMS] == NULL)
- return -EINVAL;
- parm = nla_data(tb[TCA_CSUM_PARMS]);
- if (!tcf_hash_check(parm->index, a, bind)) {
- ret = tcf_hash_create(parm->index, est, a, sizeof(*p), bind);
- if (ret)
- return ret;
- ret = ACT_P_CREATED;
- } else {
- if (bind)/* dont override defaults */
- return 0;
- tcf_hash_release(a, bind);
- if (!ovr)
- return -EEXIST;
- }
- p = to_tcf_csum(a);
- spin_lock_bh(&p->tcf_lock);
- p->tcf_action = parm->action;
- p->update_flags = parm->update_flags;
- spin_unlock_bh(&p->tcf_lock);
- if (ret == ACT_P_CREATED)
- tcf_hash_insert(a);
- return ret;
- }
- /**
- * tcf_csum_skb_nextlayer - Get next layer pointer
- * @skb: sk_buff to use
- * @ihl: previous summed headers length
- * @ipl: complete packet length
- * @jhl: next header length
- *
- * Check the expected next layer availability in the specified sk_buff.
- * Return the next layer pointer if pass, NULL otherwise.
- */
- static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl,
- unsigned int jhl)
- {
- int ntkoff = skb_network_offset(skb);
- int hl = ihl + jhl;
- if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
- (skb_cloned(skb) &&
- !skb_clone_writable(skb, hl + ntkoff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
- return NULL;
- else
- return (void *)(skb_network_header(skb) + ihl);
- }
- static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl)
- {
- struct icmphdr *icmph;
- icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
- if (icmph == NULL)
- return 0;
- icmph->checksum = 0;
- skb->csum = csum_partial(icmph, ipl - ihl, 0);
- icmph->checksum = csum_fold(skb->csum);
- skb->ip_summed = CHECKSUM_NONE;
- return 1;
- }
- static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl)
- {
- struct igmphdr *igmph;
- igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
- if (igmph == NULL)
- return 0;
- igmph->csum = 0;
- skb->csum = csum_partial(igmph, ipl - ihl, 0);
- igmph->csum = csum_fold(skb->csum);
- skb->ip_summed = CHECKSUM_NONE;
- return 1;
- }
- static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl)
- {
- struct icmp6hdr *icmp6h;
- const struct ipv6hdr *ip6h;
- icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
- if (icmp6h == NULL)
- return 0;
- ip6h = ipv6_hdr(skb);
- icmp6h->icmp6_cksum = 0;
- skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
- icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
- ipl - ihl, IPPROTO_ICMPV6,
- skb->csum);
- skb->ip_summed = CHECKSUM_NONE;
- return 1;
- }
- static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl)
- {
- struct tcphdr *tcph;
- const struct iphdr *iph;
- tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
- if (tcph == NULL)
- return 0;
- iph = ip_hdr(skb);
- tcph->check = 0;
- skb->csum = csum_partial(tcph, ipl - ihl, 0);
- tcph->check = tcp_v4_check(ipl - ihl,
- iph->saddr, iph->daddr, skb->csum);
- skb->ip_summed = CHECKSUM_NONE;
- return 1;
- }
- static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl)
- {
- struct tcphdr *tcph;
- const struct ipv6hdr *ip6h;
- tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
- if (tcph == NULL)
- return 0;
- ip6h = ipv6_hdr(skb);
- tcph->check = 0;
- skb->csum = csum_partial(tcph, ipl - ihl, 0);
- tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
- ipl - ihl, IPPROTO_TCP,
- skb->csum);
- skb->ip_summed = CHECKSUM_NONE;
- return 1;
- }
- static int tcf_csum_ipv4_udp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl, int udplite)
- {
- struct udphdr *udph;
- const struct iphdr *iph;
- u16 ul;
- /*
- * Support both UDP and UDPLITE checksum algorithms, Don't use
- * udph->len to get the real length without any protocol check,
- * UDPLITE uses udph->len for another thing,
- * Use iph->tot_len, or just ipl.
- */
- udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
- if (udph == NULL)
- return 0;
- iph = ip_hdr(skb);
- ul = ntohs(udph->len);
- if (udplite || udph->check) {
- udph->check = 0;
- if (udplite) {
- if (ul == 0)
- skb->csum = csum_partial(udph, ipl - ihl, 0);
- else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
- skb->csum = csum_partial(udph, ul, 0);
- else
- goto ignore_obscure_skb;
- } else {
- if (ul != ipl - ihl)
- goto ignore_obscure_skb;
- skb->csum = csum_partial(udph, ul, 0);
- }
- udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
- ul, iph->protocol,
- skb->csum);
- if (!udph->check)
- udph->check = CSUM_MANGLED_0;
- }
- skb->ip_summed = CHECKSUM_NONE;
- ignore_obscure_skb:
- return 1;
- }
- static int tcf_csum_ipv6_udp(struct sk_buff *skb,
- unsigned int ihl, unsigned int ipl, int udplite)
- {
- struct udphdr *udph;
- const struct ipv6hdr *ip6h;
- u16 ul;
- /*
- * Support both UDP and UDPLITE checksum algorithms, Don't use
- * udph->len to get the real length without any protocol check,
- * UDPLITE uses udph->len for another thing,
- * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
- */
- udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
- if (udph == NULL)
- return 0;
- ip6h = ipv6_hdr(skb);
- ul = ntohs(udph->len);
- udph->check = 0;
- if (udplite) {
- if (ul == 0)
- skb->csum = csum_partial(udph, ipl - ihl, 0);
- else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
- skb->csum = csum_partial(udph, ul, 0);
- else
- goto ignore_obscure_skb;
- } else {
- if (ul != ipl - ihl)
- goto ignore_obscure_skb;
- skb->csum = csum_partial(udph, ul, 0);
- }
- udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
- udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
- skb->csum);
- if (!udph->check)
- udph->check = CSUM_MANGLED_0;
- skb->ip_summed = CHECKSUM_NONE;
- ignore_obscure_skb:
- return 1;
- }
- static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
- {
- const struct iphdr *iph;
- int ntkoff;
- ntkoff = skb_network_offset(skb);
- if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
- goto fail;
- iph = ip_hdr(skb);
- switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
- case IPPROTO_ICMP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
- if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
- ntohs(iph->tot_len)))
- goto fail;
- break;
- case IPPROTO_IGMP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
- if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
- ntohs(iph->tot_len)))
- goto fail;
- break;
- case IPPROTO_TCP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
- if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
- ntohs(iph->tot_len)))
- goto fail;
- break;
- case IPPROTO_UDP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
- if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
- ntohs(iph->tot_len), 0))
- goto fail;
- break;
- case IPPROTO_UDPLITE:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
- if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
- ntohs(iph->tot_len), 1))
- goto fail;
- break;
- }
- if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
- if (skb_cloned(skb) &&
- !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
- pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
- goto fail;
- ip_send_check(ip_hdr(skb));
- }
- return 1;
- fail:
- return 0;
- }
- static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
- unsigned int ixhl, unsigned int *pl)
- {
- int off, len, optlen;
- unsigned char *xh = (void *)ip6xh;
- off = sizeof(*ip6xh);
- len = ixhl - off;
- while (len > 1) {
- switch (xh[off]) {
- case IPV6_TLV_PAD1:
- optlen = 1;
- break;
- case IPV6_TLV_JUMBO:
- optlen = xh[off + 1] + 2;
- if (optlen != 6 || len < 6 || (off & 3) != 2)
- /* wrong jumbo option length/alignment */
- return 0;
- *pl = ntohl(*(__be32 *)(xh + off + 2));
- goto done;
- default:
- optlen = xh[off + 1] + 2;
- if (optlen > len)
- /* ignore obscure options */
- goto done;
- break;
- }
- off += optlen;
- len -= optlen;
- }
- done:
- return 1;
- }
- static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
- {
- struct ipv6hdr *ip6h;
- struct ipv6_opt_hdr *ip6xh;
- unsigned int hl, ixhl;
- unsigned int pl;
- int ntkoff;
- u8 nexthdr;
- ntkoff = skb_network_offset(skb);
- hl = sizeof(*ip6h);
- if (!pskb_may_pull(skb, hl + ntkoff))
- goto fail;
- ip6h = ipv6_hdr(skb);
- pl = ntohs(ip6h->payload_len);
- nexthdr = ip6h->nexthdr;
- do {
- switch (nexthdr) {
- case NEXTHDR_FRAGMENT:
- goto ignore_skb;
- case NEXTHDR_ROUTING:
- case NEXTHDR_HOP:
- case NEXTHDR_DEST:
- if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
- goto fail;
- ip6xh = (void *)(skb_network_header(skb) + hl);
- ixhl = ipv6_optlen(ip6xh);
- if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
- goto fail;
- ip6xh = (void *)(skb_network_header(skb) + hl);
- if ((nexthdr == NEXTHDR_HOP) &&
- !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
- goto fail;
- nexthdr = ip6xh->nexthdr;
- hl += ixhl;
- break;
- case IPPROTO_ICMPV6:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
- if (!tcf_csum_ipv6_icmp(skb,
- hl, pl + sizeof(*ip6h)))
- goto fail;
- goto done;
- case IPPROTO_TCP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
- if (!tcf_csum_ipv6_tcp(skb,
- hl, pl + sizeof(*ip6h)))
- goto fail;
- goto done;
- case IPPROTO_UDP:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
- if (!tcf_csum_ipv6_udp(skb, hl,
- pl + sizeof(*ip6h), 0))
- goto fail;
- goto done;
- case IPPROTO_UDPLITE:
- if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
- if (!tcf_csum_ipv6_udp(skb, hl,
- pl + sizeof(*ip6h), 1))
- goto fail;
- goto done;
- default:
- goto ignore_skb;
- }
- } while (pskb_may_pull(skb, hl + 1 + ntkoff));
- done:
- ignore_skb:
- return 1;
- fail:
- return 0;
- }
- static int tcf_csum(struct sk_buff *skb,
- const struct tc_action *a, struct tcf_result *res)
- {
- struct tcf_csum *p = a->priv;
- int action;
- u32 update_flags;
- spin_lock(&p->tcf_lock);
- p->tcf_tm.lastuse = jiffies;
- bstats_update(&p->tcf_bstats, skb);
- action = p->tcf_action;
- update_flags = p->update_flags;
- spin_unlock(&p->tcf_lock);
- if (unlikely(action == TC_ACT_SHOT))
- goto drop;
- switch (tc_skb_protocol(skb)) {
- case cpu_to_be16(ETH_P_IP):
- if (!tcf_csum_ipv4(skb, update_flags))
- goto drop;
- break;
- case cpu_to_be16(ETH_P_IPV6):
- if (!tcf_csum_ipv6(skb, update_flags))
- goto drop;
- break;
- }
- return action;
- drop:
- spin_lock(&p->tcf_lock);
- p->tcf_qstats.drops++;
- spin_unlock(&p->tcf_lock);
- return TC_ACT_SHOT;
- }
- static int tcf_csum_dump(struct sk_buff *skb,
- struct tc_action *a, int bind, int ref)
- {
- unsigned char *b = skb_tail_pointer(skb);
- struct tcf_csum *p = a->priv;
- struct tc_csum opt = {
- .update_flags = p->update_flags,
- .index = p->tcf_index,
- .action = p->tcf_action,
- .refcnt = p->tcf_refcnt - ref,
- .bindcnt = p->tcf_bindcnt - bind,
- };
- struct tcf_t t;
- if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
- goto nla_put_failure;
- t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
- t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
- t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
- if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
- goto nla_put_failure;
- return skb->len;
- nla_put_failure:
- nlmsg_trim(skb, b);
- return -1;
- }
- static struct tc_action_ops act_csum_ops = {
- .kind = "csum",
- .type = TCA_ACT_CSUM,
- .owner = THIS_MODULE,
- .act = tcf_csum,
- .dump = tcf_csum_dump,
- .init = tcf_csum_init,
- };
- MODULE_DESCRIPTION("Checksum updating actions");
- MODULE_LICENSE("GPL");
- static int __init csum_init_module(void)
- {
- return tcf_register_action(&act_csum_ops, CSUM_TAB_MASK);
- }
- static void __exit csum_cleanup_module(void)
- {
- tcf_unregister_action(&act_csum_ops);
- }
- module_init(csum_init_module);
- module_exit(csum_cleanup_module);
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