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 == 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 0; 67 } 68 69 rcu_read_lock(); 70 71 idev = __in6_dev_get(skb->dev); 72 73 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INRECEIVES); 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 rcu_read_unlock(); 79 goto out; 80 } 81 82 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); 83 84 /* 85 * Store incoming device index. When the packet will 86 * be queued, we cannot refer to skb->dev anymore. 87 * 88 * BTW, when we send a packet for our own local address on a 89 * non-loopback interface (e.g. ethX), it is being delivered 90 * via the loopback interface (lo) here; skb->dev = loopback_dev. 91 * It, however, should be considered as if it is being 92 * arrived via the sending interface (ethX), because of the 93 * nature of scoping architecture. --yoshfuji 94 */ 95 IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex; 96 97 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) 98 goto err; 99 100 hdr = ipv6_hdr(skb); 101 102 if (hdr->version != 6) 103 goto err; 104 105 /* 106 * RFC4291 2.5.3 107 * A packet received on an interface with a destination address 108 * of loopback must be dropped. 109 */ 110 if (!(dev->flags & IFF_LOOPBACK) && 111 ipv6_addr_loopback(&hdr->daddr)) 112 goto err; 113 114 skb->transport_header = skb->network_header + sizeof(*hdr); 115 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 116 117 pkt_len = ntohs(hdr->payload_len); 118 119 /* pkt_len may be zero if Jumbo payload option is present */ 120 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 121 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { 122 IP6_INC_STATS_BH(net, 123 idev, IPSTATS_MIB_INTRUNCATEDPKTS); 124 goto drop; 125 } 126 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 127 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 128 goto drop; 129 } 130 hdr = ipv6_hdr(skb); 131 } 132 133 if (hdr->nexthdr == NEXTHDR_HOP) { 134 if (ipv6_parse_hopopts(skb) < 0) { 135 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 136 rcu_read_unlock(); 137 return 0; 138 } 139 } 140 141 rcu_read_unlock(); 142 143 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 144 ip6_rcv_finish); 145 err: 146 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 147 drop: 148 rcu_read_unlock(); 149 kfree_skb(skb); 150 out: 151 return 0; 152 } 153 154 /* 155 * Deliver the packet to the host 156 */ 157 158 159 static int ip6_input_finish(struct sk_buff *skb) 160 { 161 struct inet6_protocol *ipprot; 162 unsigned int nhoff; 163 int nexthdr, raw; 164 u8 hash; 165 struct inet6_dev *idev; 166 struct net *net = dev_net(skb->dst->dev); 167 168 /* 169 * Parse extension headers 170 */ 171 172 rcu_read_lock(); 173 resubmit: 174 idev = ip6_dst_idev(skb->dst); 175 if (!pskb_pull(skb, skb_transport_offset(skb))) 176 goto discard; 177 nhoff = IP6CB(skb)->nhoff; 178 nexthdr = skb_network_header(skb)[nhoff]; 179 180 raw = raw6_local_deliver(skb, nexthdr); 181 182 hash = nexthdr & (MAX_INET_PROTOS - 1); 183 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 184 int ret; 185 186 if (ipprot->flags & INET6_PROTO_FINAL) { 187 struct ipv6hdr *hdr; 188 189 /* Free reference early: we don't need it any more, 190 and it may hold ip_conntrack module loaded 191 indefinitely. */ 192 nf_reset(skb); 193 194 skb_postpull_rcsum(skb, skb_network_header(skb), 195 skb_network_header_len(skb)); 196 hdr = ipv6_hdr(skb); 197 if (ipv6_addr_is_multicast(&hdr->daddr) && 198 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 199 &hdr->saddr) && 200 !ipv6_is_mld(skb, nexthdr)) 201 goto discard; 202 } 203 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 204 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 205 goto discard; 206 207 ret = ipprot->handler(skb); 208 if (ret > 0) 209 goto resubmit; 210 else if (ret == 0) 211 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 212 } else { 213 if (!raw) { 214 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 215 IP6_INC_STATS_BH(net, idev, 216 IPSTATS_MIB_INUNKNOWNPROTOS); 217 icmpv6_send(skb, ICMPV6_PARAMPROB, 218 ICMPV6_UNK_NEXTHDR, nhoff, 219 skb->dev); 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_INC_STATS_BH(dev_net(skb->dst->dev), 248 ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 249 250 hdr = ipv6_hdr(skb); 251 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 252 253 #ifdef CONFIG_IPV6_MROUTE 254 /* 255 * IPv6 multicast router mode is now supported ;) 256 */ 257 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && 258 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 259 /* 260 * Okay, we try to forward - split and duplicate 261 * packets. 262 */ 263 struct sk_buff *skb2; 264 struct inet6_skb_parm *opt = IP6CB(skb); 265 266 /* Check for MLD */ 267 if (unlikely(opt->ra)) { 268 /* Check if this is a mld message */ 269 u8 *ptr = skb_network_header(skb) + opt->ra; 270 struct icmp6hdr *icmp6; 271 u8 nexthdr = hdr->nexthdr; 272 int offset; 273 274 /* Check if the value of Router Alert 275 * is for MLD (0x0000). 276 */ 277 if ((ptr[2] | ptr[3]) == 0) { 278 deliver = 0; 279 280 if (!ipv6_ext_hdr(nexthdr)) { 281 /* BUG */ 282 goto out; 283 } 284 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 285 &nexthdr); 286 if (offset < 0) 287 goto out; 288 289 if (nexthdr != IPPROTO_ICMPV6) 290 goto out; 291 292 if (!pskb_may_pull(skb, (skb_network_header(skb) + 293 offset + 1 - skb->data))) 294 goto out; 295 296 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 297 298 switch (icmp6->icmp6_type) { 299 case ICMPV6_MGM_QUERY: 300 case ICMPV6_MGM_REPORT: 301 case ICMPV6_MGM_REDUCTION: 302 case ICMPV6_MLD2_REPORT: 303 deliver = 1; 304 break; 305 } 306 goto out; 307 } 308 /* unknown RA - process it normally */ 309 } 310 311 if (deliver) 312 skb2 = skb_clone(skb, GFP_ATOMIC); 313 else { 314 skb2 = skb; 315 skb = NULL; 316 } 317 318 if (skb2) { 319 skb2->dev = skb2->dst->dev; 320 ip6_mr_input(skb2); 321 } 322 } 323 out: 324 #endif 325 if (likely(deliver)) 326 ip6_input(skb); 327 else { 328 /* discard */ 329 kfree_skb(skb); 330 } 331 332 return 0; 333 } 334