diff options
Diffstat (limited to 'net/sched/act_csum.c')
| -rw-r--r-- | net/sched/act_csum.c | 584 |
1 files changed, 584 insertions, 0 deletions
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c new file mode 100644 index 000000000..4cd5cf1ae --- /dev/null +++ b/net/sched/act_csum.c @@ -0,0 +1,584 @@ +/* + * 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); |