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 63 if (skb->pkt_type == PACKET_OTHERHOST) { 64 kfree_skb(skb); 65 return 0; 66 } 67 68 rcu_read_lock(); 69 70 idev = __in6_dev_get(skb->dev); 71 72 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES); 73 74 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || 75 !idev || unlikely(idev->cnf.disable_ipv6)) { 76 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 77 rcu_read_unlock(); 78 goto out; 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 ? ip6_dst_idev(skb->dst)->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(idev, IPSTATS_MIB_INTRUNCATEDPKTS); 122 goto drop; 123 } 124 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 125 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 126 goto drop; 127 } 128 hdr = ipv6_hdr(skb); 129 } 130 131 if (hdr->nexthdr == NEXTHDR_HOP) { 132 if (ipv6_parse_hopopts(skb) < 0) { 133 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 134 rcu_read_unlock(); 135 return 0; 136 } 137 } 138 139 rcu_read_unlock(); 140 141 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 142 ip6_rcv_finish); 143 err: 144 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 145 drop: 146 rcu_read_unlock(); 147 kfree_skb(skb); 148 out: 149 return 0; 150 } 151 152 /* 153 * Deliver the packet to the host 154 */ 155 156 157 static int ip6_input_finish(struct sk_buff *skb) 158 { 159 struct inet6_protocol *ipprot; 160 unsigned int nhoff; 161 int nexthdr, raw; 162 u8 hash; 163 struct inet6_dev *idev; 164 165 /* 166 * Parse extension headers 167 */ 168 169 rcu_read_lock(); 170 resubmit: 171 idev = ip6_dst_idev(skb->dst); 172 if (!pskb_pull(skb, skb_transport_offset(skb))) 173 goto discard; 174 nhoff = IP6CB(skb)->nhoff; 175 nexthdr = skb_network_header(skb)[nhoff]; 176 177 raw = raw6_local_deliver(skb, nexthdr); 178 179 hash = nexthdr & (MAX_INET_PROTOS - 1); 180 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 181 int ret; 182 183 if (ipprot->flags & INET6_PROTO_FINAL) { 184 struct ipv6hdr *hdr; 185 186 /* Free reference early: we don't need it any more, 187 and it may hold ip_conntrack module loaded 188 indefinitely. */ 189 nf_reset(skb); 190 191 skb_postpull_rcsum(skb, skb_network_header(skb), 192 skb_network_header_len(skb)); 193 hdr = ipv6_hdr(skb); 194 if (ipv6_addr_is_multicast(&hdr->daddr) && 195 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 196 &hdr->saddr) && 197 !ipv6_is_mld(skb, nexthdr)) 198 goto discard; 199 } 200 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 201 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 202 goto discard; 203 204 ret = ipprot->handler(skb); 205 if (ret > 0) 206 goto resubmit; 207 else if (ret == 0) 208 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 209 } else { 210 if (!raw) { 211 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 212 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS); 213 icmpv6_send(skb, ICMPV6_PARAMPROB, 214 ICMPV6_UNK_NEXTHDR, nhoff, 215 skb->dev); 216 } 217 } else 218 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 219 kfree_skb(skb); 220 } 221 rcu_read_unlock(); 222 return 0; 223 224 discard: 225 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 226 rcu_read_unlock(); 227 kfree_skb(skb); 228 return 0; 229 } 230 231 232 int ip6_input(struct sk_buff *skb) 233 { 234 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 235 ip6_input_finish); 236 } 237 238 int ip6_mc_input(struct sk_buff *skb) 239 { 240 struct ipv6hdr *hdr; 241 int deliver; 242 243 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 244 245 hdr = ipv6_hdr(skb); 246 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 247 248 #ifdef CONFIG_IPV6_MROUTE 249 /* 250 * IPv6 multicast router mode is now supported ;) 251 */ 252 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && 253 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 254 /* 255 * Okay, we try to forward - split and duplicate 256 * packets. 257 */ 258 struct sk_buff *skb2; 259 struct inet6_skb_parm *opt = IP6CB(skb); 260 261 /* Check for MLD */ 262 if (unlikely(opt->ra)) { 263 /* Check if this is a mld message */ 264 u8 *ptr = skb_network_header(skb) + opt->ra; 265 struct icmp6hdr *icmp6; 266 u8 nexthdr = hdr->nexthdr; 267 int offset; 268 269 /* Check if the value of Router Alert 270 * is for MLD (0x0000). 271 */ 272 if ((ptr[2] | ptr[3]) == 0) { 273 deliver = 0; 274 275 if (!ipv6_ext_hdr(nexthdr)) { 276 /* BUG */ 277 goto out; 278 } 279 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 280 &nexthdr); 281 if (offset < 0) 282 goto out; 283 284 if (nexthdr != IPPROTO_ICMPV6) 285 goto out; 286 287 if (!pskb_may_pull(skb, (skb_network_header(skb) + 288 offset + 1 - skb->data))) 289 goto out; 290 291 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 292 293 switch (icmp6->icmp6_type) { 294 case ICMPV6_MGM_QUERY: 295 case ICMPV6_MGM_REPORT: 296 case ICMPV6_MGM_REDUCTION: 297 case ICMPV6_MLD2_REPORT: 298 deliver = 1; 299 break; 300 } 301 goto out; 302 } 303 /* unknown RA - process it normally */ 304 } 305 306 if (deliver) 307 skb2 = skb_clone(skb, GFP_ATOMIC); 308 else { 309 skb2 = skb; 310 skb = NULL; 311 } 312 313 if (skb2) { 314 skb2->dev = skb2->dst->dev; 315 ip6_mr_input(skb2); 316 } 317 } 318 out: 319 #endif 320 if (likely(deliver)) 321 ip6_input(skb); 322 else { 323 /* discard */ 324 kfree_skb(skb); 325 } 326 327 return 0; 328 } 329