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 * $Id: ip6_input.c,v 1.19 2000/12/13 18:31:50 davem Exp $ 10 * 11 * Based in linux/net/ipv4/ip_input.c 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 */ 18 /* Changes 19 * 20 * Mitsuru KANDA @USAGI and 21 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs(). 22 */ 23 24 #include <linux/errno.h> 25 #include <linux/types.h> 26 #include <linux/socket.h> 27 #include <linux/sockios.h> 28 #include <linux/net.h> 29 #include <linux/netdevice.h> 30 #include <linux/in6.h> 31 #include <linux/icmpv6.h> 32 #include <linux/mroute6.h> 33 34 #include <linux/netfilter.h> 35 #include <linux/netfilter_ipv6.h> 36 37 #include <net/sock.h> 38 #include <net/snmp.h> 39 40 #include <net/ipv6.h> 41 #include <net/protocol.h> 42 #include <net/transp_v6.h> 43 #include <net/rawv6.h> 44 #include <net/ndisc.h> 45 #include <net/ip6_route.h> 46 #include <net/addrconf.h> 47 #include <net/xfrm.h> 48 49 50 51 inline int ip6_rcv_finish( struct sk_buff *skb) 52 { 53 if (skb->dst == NULL) 54 ip6_route_input(skb); 55 56 return dst_input(skb); 57 } 58 59 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) 60 { 61 struct ipv6hdr *hdr; 62 u32 pkt_len; 63 struct inet6_dev *idev; 64 65 if (skb->pkt_type == PACKET_OTHERHOST) { 66 kfree_skb(skb); 67 return 0; 68 } 69 70 rcu_read_lock(); 71 72 idev = __in6_dev_get(skb->dev); 73 74 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES); 75 76 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) { 77 IP6_INC_STATS_BH(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 skb->transport_header = skb->network_header + sizeof(*hdr); 106 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 107 108 pkt_len = ntohs(hdr->payload_len); 109 110 /* pkt_len may be zero if Jumbo payload option is present */ 111 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 112 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { 113 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS); 114 goto drop; 115 } 116 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 117 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 118 goto drop; 119 } 120 hdr = ipv6_hdr(skb); 121 } 122 123 if (hdr->nexthdr == NEXTHDR_HOP) { 124 if (ipv6_parse_hopopts(skb) < 0) { 125 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 126 rcu_read_unlock(); 127 return 0; 128 } 129 } 130 131 rcu_read_unlock(); 132 133 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 134 ip6_rcv_finish); 135 err: 136 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 137 drop: 138 rcu_read_unlock(); 139 kfree_skb(skb); 140 out: 141 return 0; 142 } 143 144 /* 145 * Deliver the packet to the host 146 */ 147 148 149 static int ip6_input_finish(struct sk_buff *skb) 150 { 151 struct inet6_protocol *ipprot; 152 unsigned int nhoff; 153 int nexthdr, raw; 154 u8 hash; 155 struct inet6_dev *idev; 156 157 /* 158 * Parse extension headers 159 */ 160 161 rcu_read_lock(); 162 resubmit: 163 idev = ip6_dst_idev(skb->dst); 164 if (!pskb_pull(skb, skb_transport_offset(skb))) 165 goto discard; 166 nhoff = IP6CB(skb)->nhoff; 167 nexthdr = skb_network_header(skb)[nhoff]; 168 169 raw = raw6_local_deliver(skb, nexthdr); 170 171 hash = nexthdr & (MAX_INET_PROTOS - 1); 172 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 173 int ret; 174 175 if (ipprot->flags & INET6_PROTO_FINAL) { 176 struct ipv6hdr *hdr; 177 178 /* Free reference early: we don't need it any more, 179 and it may hold ip_conntrack module loaded 180 indefinitely. */ 181 nf_reset(skb); 182 183 skb_postpull_rcsum(skb, skb_network_header(skb), 184 skb_network_header_len(skb)); 185 hdr = ipv6_hdr(skb); 186 if (ipv6_addr_is_multicast(&hdr->daddr) && 187 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 188 &hdr->saddr) && 189 !ipv6_is_mld(skb, nexthdr)) 190 goto discard; 191 } 192 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 193 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 194 goto discard; 195 196 ret = ipprot->handler(skb); 197 if (ret > 0) 198 goto resubmit; 199 else if (ret == 0) 200 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 201 } else { 202 if (!raw) { 203 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 204 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS); 205 icmpv6_send(skb, ICMPV6_PARAMPROB, 206 ICMPV6_UNK_NEXTHDR, nhoff, 207 skb->dev); 208 } 209 } else 210 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 211 kfree_skb(skb); 212 } 213 rcu_read_unlock(); 214 return 0; 215 216 discard: 217 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 218 rcu_read_unlock(); 219 kfree_skb(skb); 220 return 0; 221 } 222 223 224 int ip6_input(struct sk_buff *skb) 225 { 226 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 227 ip6_input_finish); 228 } 229 230 int ip6_mc_input(struct sk_buff *skb) 231 { 232 struct ipv6hdr *hdr; 233 int deliver; 234 235 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 236 237 hdr = ipv6_hdr(skb); 238 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 239 240 #ifdef CONFIG_IPV6_MROUTE 241 /* 242 * IPv6 multicast router mode is now supported ;) 243 */ 244 if (ipv6_devconf.mc_forwarding && 245 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 246 /* 247 * Okay, we try to forward - split and duplicate 248 * packets. 249 */ 250 struct sk_buff *skb2; 251 struct inet6_skb_parm *opt = IP6CB(skb); 252 253 /* Check for MLD */ 254 if (unlikely(opt->ra)) { 255 /* Check if this is a mld message */ 256 u8 *ptr = skb_network_header(skb) + opt->ra; 257 struct icmp6hdr *icmp6; 258 u8 nexthdr = hdr->nexthdr; 259 int offset; 260 261 /* Check if the value of Router Alert 262 * is for MLD (0x0000). 263 */ 264 if ((ptr[2] | ptr[3]) == 0) { 265 deliver = 0; 266 267 if (!ipv6_ext_hdr(nexthdr)) { 268 /* BUG */ 269 goto out; 270 } 271 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 272 &nexthdr); 273 if (offset < 0) 274 goto out; 275 276 if (nexthdr != IPPROTO_ICMPV6) 277 goto out; 278 279 if (!pskb_may_pull(skb, (skb_network_header(skb) + 280 offset + 1 - skb->data))) 281 goto out; 282 283 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 284 285 switch (icmp6->icmp6_type) { 286 case ICMPV6_MGM_QUERY: 287 case ICMPV6_MGM_REPORT: 288 case ICMPV6_MGM_REDUCTION: 289 case ICMPV6_MLD2_REPORT: 290 deliver = 1; 291 break; 292 } 293 goto out; 294 } 295 /* unknown RA - process it normally */ 296 } 297 298 if (deliver) 299 skb2 = skb_clone(skb, GFP_ATOMIC); 300 else { 301 skb2 = skb; 302 skb = NULL; 303 } 304 305 if (skb2) { 306 skb2->dev = skb2->dst->dev; 307 ip6_mr_input(skb2); 308 } 309 } 310 out: 311 #endif 312 if (likely(deliver)) 313 ip6_input(skb); 314 else { 315 /* discard */ 316 kfree_skb(skb); 317 } 318 319 return 0; 320 } 321