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#include <linux/slab.h> 32 33#include <linux/netfilter.h> 34#include <linux/netfilter_ipv6.h> 35 36#include <net/sock.h> 37#include <net/snmp.h> 38 39#include <net/ipv6.h> 40#include <net/protocol.h> 41#include <net/transp_v6.h> 42#include <net/rawv6.h> 43#include <net/ndisc.h> 44#include <net/ip6_route.h> 45#include <net/addrconf.h> 46#include <net/xfrm.h> 47 48 49 50inline int ip6_rcv_finish( struct sk_buff *skb) 51{ 52 if (skb_dst(skb) == NULL) 53 ip6_route_input(skb); 54 55 return dst_input(skb); 56} 57 58int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) 59{ 60 struct ipv6hdr *hdr; 61 u32 pkt_len; 62 struct inet6_dev *idev; 63 struct net *net = dev_net(skb->dev); 64 65 if (skb->pkt_type == PACKET_OTHERHOST) { 66 kfree_skb(skb); 67 return NET_RX_DROP; 68 } 69 70 rcu_read_lock(); 71 72 idev = __in6_dev_get(skb->dev); 73 74 IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len); 75 76 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || 77 !idev || unlikely(idev->cnf.disable_ipv6)) { 78 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 79 goto drop; 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(skb) ? ip6_dst_idev(skb_dst(skb))->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 NET_RX_DROP; 138 } 139 } 140 141 rcu_read_unlock(); 142 143 /* Must drop socket now because of tproxy. */ 144 skb_orphan(skb); 145 146 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, dev, NULL, 147 ip6_rcv_finish); 148err: 149 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); 150drop: 151 rcu_read_unlock(); 152 kfree_skb(skb); 153 return NET_RX_DROP; 154} 155 156/* 157 * Deliver the packet to the host 158 */ 159 160 161static int ip6_input_finish(struct sk_buff *skb) 162{ 163 const struct inet6_protocol *ipprot; 164 unsigned int nhoff; 165 int nexthdr, raw; 166 u8 hash; 167 struct inet6_dev *idev; 168 struct net *net = dev_net(skb_dst(skb)->dev); 169 170 /* 171 * Parse extension headers 172 */ 173 174 rcu_read_lock(); 175resubmit: 176 idev = ip6_dst_idev(skb_dst(skb)); 177 if (!pskb_pull(skb, skb_transport_offset(skb))) 178 goto discard; 179 nhoff = IP6CB(skb)->nhoff; 180 nexthdr = skb_network_header(skb)[nhoff]; 181 182 raw = raw6_local_deliver(skb, nexthdr); 183 184 hash = nexthdr & (MAX_INET_PROTOS - 1); 185 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 186 int ret; 187 188 if (ipprot->flags & INET6_PROTO_FINAL) { 189 struct ipv6hdr *hdr; 190 191 /* Free reference early: we don't need it any more, 192 and it may hold ip_conntrack module loaded 193 indefinitely. */ 194 nf_reset(skb); 195 196 skb_postpull_rcsum(skb, skb_network_header(skb), 197 skb_network_header_len(skb)); 198 hdr = ipv6_hdr(skb); 199 if (ipv6_addr_is_multicast(&hdr->daddr) && 200 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 201 &hdr->saddr) && 202 !ipv6_is_mld(skb, nexthdr)) 203 goto discard; 204 } 205 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 206 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 207 goto discard; 208 209 ret = ipprot->handler(skb); 210 if (ret > 0) 211 goto resubmit; 212 else if (ret == 0) 213 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 214 } else { 215 if (!raw) { 216 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 217 IP6_INC_STATS_BH(net, idev, 218 IPSTATS_MIB_INUNKNOWNPROTOS); 219 icmpv6_send(skb, ICMPV6_PARAMPROB, 220 ICMPV6_UNK_NEXTHDR, nhoff); 221 } 222 } else 223 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); 224 kfree_skb(skb); 225 } 226 rcu_read_unlock(); 227 return 0; 228 229discard: 230 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); 231 rcu_read_unlock(); 232 kfree_skb(skb); 233 return 0; 234} 235 236 237int ip6_input(struct sk_buff *skb) 238{ 239 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 240 ip6_input_finish); 241} 242 243int ip6_mc_input(struct sk_buff *skb) 244{ 245 struct ipv6hdr *hdr; 246 int deliver; 247 248 IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev), 249 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST, 250 skb->len); 251 252 hdr = ipv6_hdr(skb); 253 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 254 255#ifdef CONFIG_IPV6_MROUTE 256 /* 257 * IPv6 multicast router mode is now supported ;) 258 */ 259 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && 260 !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) && 261 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { 262 /* 263 * Okay, we try to forward - split and duplicate 264 * packets. 265 */ 266 struct sk_buff *skb2; 267 struct inet6_skb_parm *opt = IP6CB(skb); 268 269 /* Check for MLD */ 270 if (unlikely(opt->ra)) { 271 /* Check if this is a mld message */ 272 u8 *ptr = skb_network_header(skb) + opt->ra; 273 struct icmp6hdr *icmp6; 274 u8 nexthdr = hdr->nexthdr; 275 int offset; 276 277 /* Check if the value of Router Alert 278 * is for MLD (0x0000). 279 */ 280 if ((ptr[2] | ptr[3]) == 0) { 281 deliver = 0; 282 283 if (!ipv6_ext_hdr(nexthdr)) { 284 /* BUG */ 285 goto out; 286 } 287 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), 288 &nexthdr); 289 if (offset < 0) 290 goto out; 291 292 if (nexthdr != IPPROTO_ICMPV6) 293 goto out; 294 295 if (!pskb_may_pull(skb, (skb_network_header(skb) + 296 offset + 1 - skb->data))) 297 goto out; 298 299 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); 300 301 switch (icmp6->icmp6_type) { 302 case ICMPV6_MGM_QUERY: 303 case ICMPV6_MGM_REPORT: 304 case ICMPV6_MGM_REDUCTION: 305 case ICMPV6_MLD2_REPORT: 306 deliver = 1; 307 break; 308 } 309 goto out; 310 } 311 /* unknown RA - process it normally */ 312 } 313 314 if (deliver) 315 skb2 = skb_clone(skb, GFP_ATOMIC); 316 else { 317 skb2 = skb; 318 skb = NULL; 319 } 320 321 if (skb2) { 322 ip6_mr_input(skb2); 323 } 324 } 325out: 326#endif 327 if (likely(deliver)) 328 ip6_input(skb); 329 else { 330 /* discard */ 331 kfree_skb(skb); 332 } 333 334 return 0; 335} 336