1 /* 2 * IPv6 input 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * Ian P. Morris <I.P.Morris@soton.ac.uk> 8 * 9 * Based in linux/net/ipv4/ip_input.c 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 */ 16 /* Changes 17 * 18 * Mitsuru KANDA @USAGI and 19 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs(). 20 */ 21 22 #include <linux/errno.h> 23 #include <linux/types.h> 24 #include <linux/socket.h> 25 #include <linux/sockios.h> 26 #include <linux/net.h> 27 #include <linux/netdevice.h> 28 #include <linux/in6.h> 29 #include <linux/icmpv6.h> 30 #include <linux/mroute6.h> 31 32 #include <linux/netfilter.h> 33 #include <linux/netfilter_ipv6.h> 34 35 #include <net/sock.h> 36 #include <net/snmp.h> 37 38 #include <net/ipv6.h> 39 #include <net/protocol.h> 40 #include <net/transp_v6.h> 41 #include <net/rawv6.h> 42 #include <net/ndisc.h> 43 #include <net/ip6_route.h> 44 #include <net/addrconf.h> 45 #include <net/xfrm.h> 46 47 48 49 inline int ip6_rcv_finish( struct sk_buff *skb) 50 { 51 if (skb_dst(skb) == NULL) 52 ip6_route_input(skb); 53 54 return dst_input(skb); 55 } 56 57 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) 58 { 59 struct ipv6hdr *hdr; 60 u32 pkt_len; 61 struct inet6_dev *idev; 62 struct net *net = dev_net(skb->dev); 63 64 if (skb->pkt_type == PACKET_OTHERHOST) { 65 kfree_skb(skb); 66 return NET_RX_DROP; 67 } 68 69 rcu_read_lock(); 70 71 idev = __in6_dev_get(skb->dev); 72 73 IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len); 74 75 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || 76 !idev || unlikely(idev->cnf.disable_ipv6)) { 77 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 78 goto drop; 79 } 80 81 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); 82 83 /* 84 * Store incoming device index. When the packet will 85 * be queued, we cannot refer to skb->dev anymore. 86 * 87 * BTW, when we send a packet for our own local address on a 88 * non-loopback interface (e.g. ethX), it is being delivered 89 * via the loopback interface (lo) here; skb->dev = loopback_dev. 90 * It, however, should be considered as if it is being 91 * arrived via the sending interface (ethX), because of the 92 * nature of scoping architecture. --yoshfuji 93 */ 94 IP6CB(skb)->iif = skb_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex; 95 96 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) 97 goto err; 98 99 hdr = ipv6_hdr(skb); 100 101 if (hdr->version != 6) 102 goto err; 103 104 /* 105 * RFC4291 2.5.3 106 * A packet received on an interface with a destination address 107 * of loopback must be dropped. 108 */ 109 if (!(dev->flags & IFF_LOOPBACK) && 110 ipv6_addr_loopback(&hdr->daddr)) 111 goto err; 112 113 skb->transport_header = skb->network_header + sizeof(*hdr); 114 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 115 116 pkt_len = ntohs(hdr->payload_len); 117 118 /* pkt_len may be zero if Jumbo payload option is present */ 119 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 120 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { 121 IP6_INC_STATS_BH(net, 122 idev, IPSTATS_MIB_INTRUNCATEDPKTS); 123 goto drop; 124 } 125 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 126 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 127 goto drop; 128 } 129 hdr = ipv6_hdr(skb); 130 } 131 132 if (hdr->nexthdr == NEXTHDR_HOP) { 133 if (ipv6_parse_hopopts(skb) < 0) { 134 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 135 rcu_read_unlock(); 136 return NET_RX_DROP; 137 } 138 } 139 140 rcu_read_unlock(); 141 142 /* Must drop socket now because of tproxy. */ 143 skb_orphan(skb); 144 145 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 146 ip6_rcv_finish); 147 err: 148 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 149 drop: 150 rcu_read_unlock(); 151 kfree_skb(skb); 152 return NET_RX_DROP; 153 } 154 155 /* 156 * Deliver the packet to the host 157 */ 158 159 160 static int ip6_input_finish(struct sk_buff *skb) 161 { 162 const struct inet6_protocol *ipprot; 163 unsigned int nhoff; 164 int nexthdr, raw; 165 u8 hash; 166 struct inet6_dev *idev; 167 struct net *net = dev_net(skb_dst(skb)->dev); 168 169 /* 170 * Parse extension headers 171 */ 172 173 rcu_read_lock(); 174 resubmit: 175 idev = ip6_dst_idev(skb_dst(skb)); 176 if (!pskb_pull(skb, skb_transport_offset(skb))) 177 goto discard; 178 nhoff = IP6CB(skb)->nhoff; 179 nexthdr = skb_network_header(skb)[nhoff]; 180 181 raw = raw6_local_deliver(skb, nexthdr); 182 183 hash = nexthdr & (MAX_INET_PROTOS - 1); 184 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 185 int ret; 186 187 if (ipprot->flags & INET6_PROTO_FINAL) { 188 struct ipv6hdr *hdr; 189 190 /* Free reference early: we don't need it any more, 191 and it may hold ip_conntrack module loaded 192 indefinitely. */ 193 nf_reset(skb); 194 195 skb_postpull_rcsum(skb, skb_network_header(skb), 196 skb_network_header_len(skb)); 197 hdr = ipv6_hdr(skb); 198 if (ipv6_addr_is_multicast(&hdr->daddr) && 199 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 200 &hdr->saddr) && 201 !ipv6_is_mld(skb, nexthdr)) 202 goto discard; 203 } 204 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 205 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 206 goto discard; 207 208 ret = ipprot->handler(skb); 209 if (ret > 0) 210 goto resubmit; 211 else if (ret == 0) 212 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 213 } else { 214 if (!raw) { 215 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 216 IP6_INC_STATS_BH(net, idev, 217 IPSTATS_MIB_INUNKNOWNPROTOS); 218 icmpv6_send(skb, ICMPV6_PARAMPROB, 219 ICMPV6_UNK_NEXTHDR, nhoff); 220 } 221 } else 222 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 223 kfree_skb(skb); 224 } 225 rcu_read_unlock(); 226 return 0; 227 228 discard: 229 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 230 rcu_read_unlock(); 231 kfree_skb(skb); 232 return 0; 233 } 234 235 236 int ip6_input(struct sk_buff *skb) 237 { 238 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 239 ip6_input_finish); 240 } 241 242 int ip6_mc_input(struct sk_buff *skb) 243 { 244 struct ipv6hdr *hdr; 245 int deliver; 246 247 IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev), 248 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST, 249 skb->len); 250 251 hdr = ipv6_hdr(skb); 252 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 253 254 #ifdef CONFIG_IPV6_MROUTE 255 /* 256 * IPv6 multicast router mode is now supported ;) 257 */ 258 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && 259 !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) && 260 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 261 /* 262 * Okay, we try to forward - split and duplicate 263 * packets. 264 */ 265 struct sk_buff *skb2; 266 struct inet6_skb_parm *opt = IP6CB(skb); 267 268 /* Check for MLD */ 269 if (unlikely(opt->ra)) { 270 /* Check if this is a mld message */ 271 u8 *ptr = skb_network_header(skb) + opt->ra; 272 struct icmp6hdr *icmp6; 273 u8 nexthdr = hdr->nexthdr; 274 int offset; 275 276 /* Check if the value of Router Alert 277 * is for MLD (0x0000). 278 */ 279 if ((ptr[2] | ptr[3]) == 0) { 280 deliver = 0; 281 282 if (!ipv6_ext_hdr(nexthdr)) { 283 /* BUG */ 284 goto out; 285 } 286 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 287 &nexthdr); 288 if (offset < 0) 289 goto out; 290 291 if (nexthdr != IPPROTO_ICMPV6) 292 goto out; 293 294 if (!pskb_may_pull(skb, (skb_network_header(skb) + 295 offset + 1 - skb->data))) 296 goto out; 297 298 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 299 300 switch (icmp6->icmp6_type) { 301 case ICMPV6_MGM_QUERY: 302 case ICMPV6_MGM_REPORT: 303 case ICMPV6_MGM_REDUCTION: 304 case ICMPV6_MLD2_REPORT: 305 deliver = 1; 306 break; 307 } 308 goto out; 309 } 310 /* unknown RA - process it normally */ 311 } 312 313 if (deliver) 314 skb2 = skb_clone(skb, GFP_ATOMIC); 315 else { 316 skb2 = skb; 317 skb = NULL; 318 } 319 320 if (skb2) { 321 ip6_mr_input(skb2); 322 } 323 } 324 out: 325 #endif 326 if (likely(deliver)) 327 ip6_input(skb); 328 else { 329 /* discard */ 330 kfree_skb(skb); 331 } 332 333 return 0; 334 } 335