1 #include <linux/kernel.h> 2 #include <linux/init.h> 3 #include <linux/ipv6.h> 4 #include <linux/netfilter.h> 5 #include <linux/netfilter_ipv6.h> 6 #include <net/dst.h> 7 #include <net/ipv6.h> 8 #include <net/ip6_route.h> 9 #include <net/xfrm.h> 10 #include <net/ip6_checksum.h> 11 #include <net/netfilter/nf_queue.h> 12 13 int ip6_route_me_harder(struct sk_buff *skb) 14 { 15 struct net *net = dev_net(skb_dst(skb)->dev); 16 const struct ipv6hdr *iph = ipv6_hdr(skb); 17 struct dst_entry *dst; 18 struct flowi6 fl6 = { 19 .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0, 20 .flowi6_mark = skb->mark, 21 .daddr = iph->daddr, 22 .saddr = iph->saddr, 23 }; 24 25 dst = ip6_route_output(net, skb->sk, &fl6); 26 if (dst->error) { 27 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 28 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n"); 29 dst_release(dst); 30 return -EINVAL; 31 } 32 33 /* Drop old route. */ 34 skb_dst_drop(skb); 35 36 skb_dst_set(skb, dst); 37 38 #ifdef CONFIG_XFRM 39 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && 40 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { 41 skb_dst_set(skb, NULL); 42 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0); 43 if (IS_ERR(dst)) 44 return -1; 45 skb_dst_set(skb, dst); 46 } 47 #endif 48 49 return 0; 50 } 51 EXPORT_SYMBOL(ip6_route_me_harder); 52 53 /* 54 * Extra routing may needed on local out, as the QUEUE target never 55 * returns control to the table. 56 */ 57 58 struct ip6_rt_info { 59 struct in6_addr daddr; 60 struct in6_addr saddr; 61 u_int32_t mark; 62 }; 63 64 static void nf_ip6_saveroute(const struct sk_buff *skb, 65 struct nf_queue_entry *entry) 66 { 67 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 68 69 if (entry->hook == NF_INET_LOCAL_OUT) { 70 const struct ipv6hdr *iph = ipv6_hdr(skb); 71 72 rt_info->daddr = iph->daddr; 73 rt_info->saddr = iph->saddr; 74 rt_info->mark = skb->mark; 75 } 76 } 77 78 static int nf_ip6_reroute(struct sk_buff *skb, 79 const struct nf_queue_entry *entry) 80 { 81 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 82 83 if (entry->hook == NF_INET_LOCAL_OUT) { 84 const struct ipv6hdr *iph = ipv6_hdr(skb); 85 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || 86 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || 87 skb->mark != rt_info->mark) 88 return ip6_route_me_harder(skb); 89 } 90 return 0; 91 } 92 93 static int nf_ip6_route(struct net *net, struct dst_entry **dst, 94 struct flowi *fl, bool strict) 95 { 96 static const struct ipv6_pinfo fake_pinfo; 97 static const struct inet_sock fake_sk = { 98 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ 99 .sk.sk_bound_dev_if = 1, 100 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, 101 }; 102 const void *sk = strict ? &fake_sk : NULL; 103 104 *dst = ip6_route_output(net, sk, &fl->u.ip6); 105 return (*dst)->error; 106 } 107 108 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, 109 unsigned int dataoff, u_int8_t protocol) 110 { 111 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 112 __sum16 csum = 0; 113 114 switch (skb->ip_summed) { 115 case CHECKSUM_COMPLETE: 116 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) 117 break; 118 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 119 skb->len - dataoff, protocol, 120 csum_sub(skb->csum, 121 skb_checksum(skb, 0, 122 dataoff, 0)))) { 123 skb->ip_summed = CHECKSUM_UNNECESSARY; 124 break; 125 } 126 /* fall through */ 127 case CHECKSUM_NONE: 128 skb->csum = ~csum_unfold( 129 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 130 skb->len - dataoff, 131 protocol, 132 csum_sub(0, 133 skb_checksum(skb, 0, 134 dataoff, 0)))); 135 csum = __skb_checksum_complete(skb); 136 } 137 return csum; 138 } 139 EXPORT_SYMBOL(nf_ip6_checksum); 140 141 static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, 142 unsigned int dataoff, unsigned int len, 143 u_int8_t protocol) 144 { 145 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 146 __wsum hsum; 147 __sum16 csum = 0; 148 149 switch (skb->ip_summed) { 150 case CHECKSUM_COMPLETE: 151 if (len == skb->len - dataoff) 152 return nf_ip6_checksum(skb, hook, dataoff, protocol); 153 /* fall through */ 154 case CHECKSUM_NONE: 155 hsum = skb_checksum(skb, 0, dataoff, 0); 156 skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, 157 &ip6h->daddr, 158 skb->len - dataoff, 159 protocol, 160 csum_sub(0, hsum))); 161 skb->ip_summed = CHECKSUM_NONE; 162 return __skb_checksum_complete_head(skb, dataoff + len); 163 } 164 return csum; 165 }; 166 167 static const struct nf_afinfo nf_ip6_afinfo = { 168 .family = AF_INET6, 169 .checksum = nf_ip6_checksum, 170 .checksum_partial = nf_ip6_checksum_partial, 171 .route = nf_ip6_route, 172 .saveroute = nf_ip6_saveroute, 173 .reroute = nf_ip6_reroute, 174 .route_key_size = sizeof(struct ip6_rt_info), 175 }; 176 177 int __init ipv6_netfilter_init(void) 178 { 179 return nf_register_afinfo(&nf_ip6_afinfo); 180 } 181 182 /* This can be called from inet6_init() on errors, so it cannot 183 * be marked __exit. -DaveM 184 */ 185 void ipv6_netfilter_fini(void) 186 { 187 nf_unregister_afinfo(&nf_ip6_afinfo); 188 } 189