diff options
Diffstat (limited to 'net/ipv6/netfilter.c')
| -rw-r--r-- | net/ipv6/netfilter.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c new file mode 100644 index 00000000..db31561c --- /dev/null +++ b/net/ipv6/netfilter.c @@ -0,0 +1,196 @@ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/ipv6.h> +#include <linux/netfilter.h> +#include <linux/netfilter_ipv6.h> +#include <linux/export.h> +#include <net/dst.h> +#include <net/ipv6.h> +#include <net/ip6_route.h> +#include <net/xfrm.h> +#include <net/ip6_checksum.h> +#include <net/netfilter/nf_queue.h> + +int ip6_route_me_harder(struct sk_buff *skb) +{ + struct net *net = dev_net(skb_dst(skb)->dev); + const struct ipv6hdr *iph = ipv6_hdr(skb); + struct dst_entry *dst; + struct flowi6 fl6 = { + .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0, + .flowi6_mark = skb->mark, + .daddr = iph->daddr, + .saddr = iph->saddr, + }; + + dst = ip6_route_output(net, skb->sk, &fl6); + if (dst->error) { + IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); + LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n"); + dst_release(dst); + return -EINVAL; + } + + /* Drop old route. */ + skb_dst_drop(skb); + + skb_dst_set(skb, dst); + +#ifdef CONFIG_XFRM + if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && + xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { + skb_dst_set(skb, NULL); + dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0); + if (IS_ERR(dst)) + return -1; + skb_dst_set(skb, dst); + } +#endif + + return 0; +} +EXPORT_SYMBOL(ip6_route_me_harder); + +/* + * Extra routing may needed on local out, as the QUEUE target never + * returns control to the table. + */ + +struct ip6_rt_info { + struct in6_addr daddr; + struct in6_addr saddr; + u_int32_t mark; +}; + +static void nf_ip6_saveroute(const struct sk_buff *skb, + struct nf_queue_entry *entry) +{ + struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); + + if (entry->hook == NF_INET_LOCAL_OUT) { + const struct ipv6hdr *iph = ipv6_hdr(skb); + + rt_info->daddr = iph->daddr; + rt_info->saddr = iph->saddr; + rt_info->mark = skb->mark; + } +} + +static int nf_ip6_reroute(struct sk_buff *skb, + const struct nf_queue_entry *entry) +{ + struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); + + if (entry->hook == NF_INET_LOCAL_OUT) { + const struct ipv6hdr *iph = ipv6_hdr(skb); + if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || + !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || + skb->mark != rt_info->mark) + return ip6_route_me_harder(skb); + } + return 0; +} + +static int nf_ip6_route(struct net *net, struct dst_entry **dst, + struct flowi *fl, bool strict) +{ + static const struct ipv6_pinfo fake_pinfo; + static const struct inet_sock fake_sk = { + /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ + .sk.sk_bound_dev_if = 1, + .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, + }; + const void *sk = strict ? &fake_sk : NULL; + struct dst_entry *result; + int err; + + result = ip6_route_output(net, sk, &fl->u.ip6); + err = result->error; + if (err) + dst_release(result); + else + *dst = result; + return err; +} + +__sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, + unsigned int dataoff, u_int8_t protocol) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + __sum16 csum = 0; + + switch (skb->ip_summed) { + case CHECKSUM_COMPLETE: + if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) + break; + if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, + skb->len - dataoff, protocol, + csum_sub(skb->csum, + skb_checksum(skb, 0, + dataoff, 0)))) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + break; + } + /* fall through */ + case CHECKSUM_NONE: + skb->csum = ~csum_unfold( + csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, + skb->len - dataoff, + protocol, + csum_sub(0, + skb_checksum(skb, 0, + dataoff, 0)))); + csum = __skb_checksum_complete(skb); + } + return csum; +} +EXPORT_SYMBOL(nf_ip6_checksum); + +static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, + unsigned int dataoff, unsigned int len, + u_int8_t protocol) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + __wsum hsum; + __sum16 csum = 0; + + switch (skb->ip_summed) { + case CHECKSUM_COMPLETE: + if (len == skb->len - dataoff) + return nf_ip6_checksum(skb, hook, dataoff, protocol); + /* fall through */ + case CHECKSUM_NONE: + hsum = skb_checksum(skb, 0, dataoff, 0); + skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, + &ip6h->daddr, + skb->len - dataoff, + protocol, + csum_sub(0, hsum))); + skb->ip_summed = CHECKSUM_NONE; + return __skb_checksum_complete_head(skb, dataoff + len); + } + return csum; +}; + +static const struct nf_afinfo nf_ip6_afinfo = { + .family = AF_INET6, + .checksum = nf_ip6_checksum, + .checksum_partial = nf_ip6_checksum_partial, + .route = nf_ip6_route, + .saveroute = nf_ip6_saveroute, + .reroute = nf_ip6_reroute, + .route_key_size = sizeof(struct ip6_rt_info), +}; + +int __init ipv6_netfilter_init(void) +{ + return nf_register_afinfo(&nf_ip6_afinfo); +} + +/* This can be called from inet6_init() on errors, so it cannot + * be marked __exit. -DaveM + */ +void ipv6_netfilter_fini(void) +{ + nf_unregister_afinfo(&nf_ip6_afinfo); +} |