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 <linux/export.h> 7 #include <net/dst.h> 8 #include <net/ipv6.h> 9 #include <net/ip6_route.h> 10 #include <net/xfrm.h> 11 #include <net/ip6_checksum.h> 12 #include <net/netfilter/nf_queue.h> 13 14 int ip6_route_me_harder(struct sk_buff *skb) 15 { 16 struct net *net = dev_net(skb_dst(skb)->dev); 17 const struct ipv6hdr *iph = ipv6_hdr(skb); 18 struct dst_entry *dst; 19 struct flowi6 fl6 = { 20 .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0, 21 .flowi6_mark = skb->mark, 22 .daddr = iph->daddr, 23 .saddr = iph->saddr, 24 }; 25 26 dst = ip6_route_output(net, skb->sk, &fl6); 27 if (dst->error) { 28 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 29 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n"); 30 dst_release(dst); 31 return -EINVAL; 32 } 33 34 /* Drop old route. */ 35 skb_dst_drop(skb); 36 37 skb_dst_set(skb, dst); 38 39 #ifdef CONFIG_XFRM 40 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && 41 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { 42 skb_dst_set(skb, NULL); 43 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0); 44 if (IS_ERR(dst)) 45 return -1; 46 skb_dst_set(skb, dst); 47 } 48 #endif 49 50 return 0; 51 } 52 EXPORT_SYMBOL(ip6_route_me_harder); 53 54 /* 55 * Extra routing may needed on local out, as the QUEUE target never 56 * returns control to the table. 57 */ 58 59 struct ip6_rt_info { 60 struct in6_addr daddr; 61 struct in6_addr saddr; 62 u_int32_t mark; 63 }; 64 65 static void nf_ip6_saveroute(const struct sk_buff *skb, 66 struct nf_queue_entry *entry) 67 { 68 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 69 70 if (entry->hook == NF_INET_LOCAL_OUT) { 71 const struct ipv6hdr *iph = ipv6_hdr(skb); 72 73 rt_info->daddr = iph->daddr; 74 rt_info->saddr = iph->saddr; 75 rt_info->mark = skb->mark; 76 } 77 } 78 79 static int nf_ip6_reroute(struct sk_buff *skb, 80 const struct nf_queue_entry *entry) 81 { 82 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 83 84 if (entry->hook == NF_INET_LOCAL_OUT) { 85 const struct ipv6hdr *iph = ipv6_hdr(skb); 86 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || 87 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || 88 skb->mark != rt_info->mark) 89 return ip6_route_me_harder(skb); 90 } 91 return 0; 92 } 93 94 static int nf_ip6_route(struct net *net, struct dst_entry **dst, 95 struct flowi *fl, bool strict) 96 { 97 static const struct ipv6_pinfo fake_pinfo; 98 static const struct inet_sock fake_sk = { 99 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ 100 .sk.sk_bound_dev_if = 1, 101 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, 102 }; 103 const void *sk = strict ? &fake_sk : NULL; 104 struct dst_entry *result; 105 int err; 106 107 result = ip6_route_output(net, sk, &fl->u.ip6); 108 err = result->error; 109 if (err) 110 dst_release(result); 111 else 112 *dst = result; 113 return err; 114 } 115 116 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, 117 unsigned int dataoff, u_int8_t protocol) 118 { 119 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 120 __sum16 csum = 0; 121 122 switch (skb->ip_summed) { 123 case CHECKSUM_COMPLETE: 124 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) 125 break; 126 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 127 skb->len - dataoff, protocol, 128 csum_sub(skb->csum, 129 skb_checksum(skb, 0, 130 dataoff, 0)))) { 131 skb->ip_summed = CHECKSUM_UNNECESSARY; 132 break; 133 } 134 /* fall through */ 135 case CHECKSUM_NONE: 136 skb->csum = ~csum_unfold( 137 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 138 skb->len - dataoff, 139 protocol, 140 csum_sub(0, 141 skb_checksum(skb, 0, 142 dataoff, 0)))); 143 csum = __skb_checksum_complete(skb); 144 } 145 return csum; 146 } 147 EXPORT_SYMBOL(nf_ip6_checksum); 148 149 static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, 150 unsigned int dataoff, unsigned int len, 151 u_int8_t protocol) 152 { 153 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 154 __wsum hsum; 155 __sum16 csum = 0; 156 157 switch (skb->ip_summed) { 158 case CHECKSUM_COMPLETE: 159 if (len == skb->len - dataoff) 160 return nf_ip6_checksum(skb, hook, dataoff, protocol); 161 /* fall through */ 162 case CHECKSUM_NONE: 163 hsum = skb_checksum(skb, 0, dataoff, 0); 164 skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, 165 &ip6h->daddr, 166 skb->len - dataoff, 167 protocol, 168 csum_sub(0, hsum))); 169 skb->ip_summed = CHECKSUM_NONE; 170 return __skb_checksum_complete_head(skb, dataoff + len); 171 } 172 return csum; 173 }; 174 175 static const struct nf_afinfo nf_ip6_afinfo = { 176 .family = AF_INET6, 177 .checksum = nf_ip6_checksum, 178 .checksum_partial = nf_ip6_checksum_partial, 179 .route = nf_ip6_route, 180 .saveroute = nf_ip6_saveroute, 181 .reroute = nf_ip6_reroute, 182 .route_key_size = sizeof(struct ip6_rt_info), 183 }; 184 185 int __init ipv6_netfilter_init(void) 186 { 187 return nf_register_afinfo(&nf_ip6_afinfo); 188 } 189 190 /* This can be called from inet6_init() on errors, so it cannot 191 * be marked __exit. -DaveM 192 */ 193 void ipv6_netfilter_fini(void) 194 { 195 nf_unregister_afinfo(&nf_ip6_afinfo); 196 } 197