1 /* 2 * IPv6 specific functions of netfilter core 3 * 4 * Rusty Russell (C) 2000 -- This code is GPL. 5 * Patrick McHardy (C) 2006-2012 6 */ 7 #include <linux/kernel.h> 8 #include <linux/init.h> 9 #include <linux/ipv6.h> 10 #include <linux/netfilter.h> 11 #include <linux/netfilter_ipv6.h> 12 #include <linux/export.h> 13 #include <net/addrconf.h> 14 #include <net/dst.h> 15 #include <net/ipv6.h> 16 #include <net/ip6_route.h> 17 #include <net/xfrm.h> 18 #include <net/netfilter/nf_queue.h> 19 20 int ip6_route_me_harder(struct net *net, struct sk_buff *skb) 21 { 22 const struct ipv6hdr *iph = ipv6_hdr(skb); 23 struct sock *sk = sk_to_full_sk(skb->sk); 24 unsigned int hh_len; 25 struct dst_entry *dst; 26 struct flowi6 fl6 = { 27 .flowi6_oif = sk ? sk->sk_bound_dev_if : 0, 28 .flowi6_mark = skb->mark, 29 .flowi6_uid = sock_net_uid(net, sk), 30 .daddr = iph->daddr, 31 .saddr = iph->saddr, 32 }; 33 int err; 34 35 dst = ip6_route_output(net, sk, &fl6); 36 err = dst->error; 37 if (err) { 38 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 39 net_dbg_ratelimited("ip6_route_me_harder: No more route\n"); 40 dst_release(dst); 41 return err; 42 } 43 44 /* Drop old route. */ 45 skb_dst_drop(skb); 46 47 skb_dst_set(skb, dst); 48 49 #ifdef CONFIG_XFRM 50 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && 51 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { 52 skb_dst_set(skb, NULL); 53 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 54 if (IS_ERR(dst)) 55 return PTR_ERR(dst); 56 skb_dst_set(skb, dst); 57 } 58 #endif 59 60 /* Change in oif may mean change in hh_len. */ 61 hh_len = skb_dst(skb)->dev->hard_header_len; 62 if (skb_headroom(skb) < hh_len && 63 pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), 64 0, GFP_ATOMIC)) 65 return -ENOMEM; 66 67 return 0; 68 } 69 EXPORT_SYMBOL(ip6_route_me_harder); 70 71 static int nf_ip6_reroute(struct sk_buff *skb, 72 const struct nf_queue_entry *entry) 73 { 74 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 75 76 if (entry->state.hook == NF_INET_LOCAL_OUT) { 77 const struct ipv6hdr *iph = ipv6_hdr(skb); 78 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || 79 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || 80 skb->mark != rt_info->mark) 81 return ip6_route_me_harder(entry->state.net, skb); 82 } 83 return 0; 84 } 85 86 static int nf_ip6_route(struct net *net, struct dst_entry **dst, 87 struct flowi *fl, bool strict) 88 { 89 static const struct ipv6_pinfo fake_pinfo; 90 static const struct inet_sock fake_sk = { 91 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ 92 .sk.sk_bound_dev_if = 1, 93 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, 94 }; 95 const void *sk = strict ? &fake_sk : NULL; 96 struct dst_entry *result; 97 int err; 98 99 result = ip6_route_output(net, sk, &fl->u.ip6); 100 err = result->error; 101 if (err) 102 dst_release(result); 103 else 104 *dst = result; 105 return err; 106 } 107 108 static const struct nf_ipv6_ops ipv6ops = { 109 .chk_addr = ipv6_chk_addr, 110 .route_input = ip6_route_input, 111 .fragment = ip6_fragment, 112 .route = nf_ip6_route, 113 .reroute = nf_ip6_reroute, 114 }; 115 116 int __init ipv6_netfilter_init(void) 117 { 118 RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops); 119 return 0; 120 } 121 122 /* This can be called from inet6_init() on errors, so it cannot 123 * be marked __exit. -DaveM 124 */ 125 void ipv6_netfilter_fini(void) 126 { 127 RCU_INIT_POINTER(nf_ipv6_ops, NULL); 128 } 129