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 unsigned int hh_len; 19 struct dst_entry *dst; 20 struct flowi6 fl6 = { 21 .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0, 22 .flowi6_mark = skb->mark, 23 .daddr = iph->daddr, 24 .saddr = iph->saddr, 25 }; 26 27 dst = ip6_route_output(net, skb->sk, &fl6); 28 if (dst->error) { 29 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); 30 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n"); 31 dst_release(dst); 32 return -EINVAL; 33 } 34 35 /* Drop old route. */ 36 skb_dst_drop(skb); 37 38 skb_dst_set(skb, dst); 39 40 #ifdef CONFIG_XFRM 41 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && 42 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { 43 skb_dst_set(skb, NULL); 44 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0); 45 if (IS_ERR(dst)) 46 return -1; 47 skb_dst_set(skb, dst); 48 } 49 #endif 50 51 /* Change in oif may mean change in hh_len. */ 52 hh_len = skb_dst(skb)->dev->hard_header_len; 53 if (skb_headroom(skb) < hh_len && 54 pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), 55 0, GFP_ATOMIC)) 56 return -1; 57 58 return 0; 59 } 60 EXPORT_SYMBOL(ip6_route_me_harder); 61 62 /* 63 * Extra routing may needed on local out, as the QUEUE target never 64 * returns control to the table. 65 */ 66 67 struct ip6_rt_info { 68 struct in6_addr daddr; 69 struct in6_addr saddr; 70 u_int32_t mark; 71 }; 72 73 static void nf_ip6_saveroute(const struct sk_buff *skb, 74 struct nf_queue_entry *entry) 75 { 76 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 77 78 if (entry->hook == NF_INET_LOCAL_OUT) { 79 const struct ipv6hdr *iph = ipv6_hdr(skb); 80 81 rt_info->daddr = iph->daddr; 82 rt_info->saddr = iph->saddr; 83 rt_info->mark = skb->mark; 84 } 85 } 86 87 static int nf_ip6_reroute(struct sk_buff *skb, 88 const struct nf_queue_entry *entry) 89 { 90 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); 91 92 if (entry->hook == NF_INET_LOCAL_OUT) { 93 const struct ipv6hdr *iph = ipv6_hdr(skb); 94 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || 95 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || 96 skb->mark != rt_info->mark) 97 return ip6_route_me_harder(skb); 98 } 99 return 0; 100 } 101 102 static int nf_ip6_route(struct net *net, struct dst_entry **dst, 103 struct flowi *fl, bool strict) 104 { 105 static const struct ipv6_pinfo fake_pinfo; 106 static const struct inet_sock fake_sk = { 107 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ 108 .sk.sk_bound_dev_if = 1, 109 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, 110 }; 111 const void *sk = strict ? &fake_sk : NULL; 112 struct dst_entry *result; 113 int err; 114 115 result = ip6_route_output(net, sk, &fl->u.ip6); 116 err = result->error; 117 if (err) 118 dst_release(result); 119 else 120 *dst = result; 121 return err; 122 } 123 124 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, 125 unsigned int dataoff, u_int8_t protocol) 126 { 127 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 128 __sum16 csum = 0; 129 130 switch (skb->ip_summed) { 131 case CHECKSUM_COMPLETE: 132 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) 133 break; 134 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 135 skb->len - dataoff, protocol, 136 csum_sub(skb->csum, 137 skb_checksum(skb, 0, 138 dataoff, 0)))) { 139 skb->ip_summed = CHECKSUM_UNNECESSARY; 140 break; 141 } 142 /* fall through */ 143 case CHECKSUM_NONE: 144 skb->csum = ~csum_unfold( 145 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 146 skb->len - dataoff, 147 protocol, 148 csum_sub(0, 149 skb_checksum(skb, 0, 150 dataoff, 0)))); 151 csum = __skb_checksum_complete(skb); 152 } 153 return csum; 154 } 155 EXPORT_SYMBOL(nf_ip6_checksum); 156 157 static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, 158 unsigned int dataoff, unsigned int len, 159 u_int8_t protocol) 160 { 161 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 162 __wsum hsum; 163 __sum16 csum = 0; 164 165 switch (skb->ip_summed) { 166 case CHECKSUM_COMPLETE: 167 if (len == skb->len - dataoff) 168 return nf_ip6_checksum(skb, hook, dataoff, protocol); 169 /* fall through */ 170 case CHECKSUM_NONE: 171 hsum = skb_checksum(skb, 0, dataoff, 0); 172 skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, 173 &ip6h->daddr, 174 skb->len - dataoff, 175 protocol, 176 csum_sub(0, hsum))); 177 skb->ip_summed = CHECKSUM_NONE; 178 return __skb_checksum_complete_head(skb, dataoff + len); 179 } 180 return csum; 181 }; 182 183 static const struct nf_afinfo nf_ip6_afinfo = { 184 .family = AF_INET6, 185 .checksum = nf_ip6_checksum, 186 .checksum_partial = nf_ip6_checksum_partial, 187 .route = nf_ip6_route, 188 .saveroute = nf_ip6_saveroute, 189 .reroute = nf_ip6_reroute, 190 .route_key_size = sizeof(struct ip6_rt_info), 191 }; 192 193 int __init ipv6_netfilter_init(void) 194 { 195 return nf_register_afinfo(&nf_ip6_afinfo); 196 } 197 198 /* This can be called from inet6_init() on errors, so it cannot 199 * be marked __exit. -DaveM 200 */ 201 void ipv6_netfilter_fini(void) 202 { 203 nf_unregister_afinfo(&nf_ip6_afinfo); 204 } 205