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/sched.h> 29 #include <linux/net.h> 30 #include <linux/netdevice.h> 31 #include <linux/in6.h> 32 #include <linux/icmpv6.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 = skb->nh.ipv6h; 101 102 if (hdr->version != 6) 103 goto err; 104 105 skb->h.raw = (u8 *)(hdr + 1); 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 goto truncated; 114 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 115 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 116 goto drop; 117 } 118 hdr = skb->nh.ipv6h; 119 } 120 121 if (hdr->nexthdr == NEXTHDR_HOP) { 122 if (ipv6_parse_hopopts(&skb) < 0) { 123 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 124 rcu_read_unlock(); 125 return 0; 126 } 127 } 128 129 rcu_read_unlock(); 130 131 return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish); 132 truncated: 133 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS); 134 err: 135 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 136 drop: 137 rcu_read_unlock(); 138 kfree_skb(skb); 139 out: 140 return 0; 141 } 142 143 /* 144 * Deliver the packet to the host 145 */ 146 147 148 static inline int ip6_input_finish(struct sk_buff *skb) 149 { 150 struct inet6_protocol *ipprot; 151 struct sock *raw_sk; 152 unsigned int nhoff; 153 int nexthdr; 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->h.raw - skb->data)) 165 goto discard; 166 nhoff = IP6CB(skb)->nhoff; 167 nexthdr = skb->nh.raw[nhoff]; 168 169 raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]); 170 if (raw_sk && !ipv6_raw_deliver(skb, nexthdr)) 171 raw_sk = NULL; 172 173 hash = nexthdr & (MAX_INET_PROTOS - 1); 174 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 175 int ret; 176 177 if (ipprot->flags & INET6_PROTO_FINAL) { 178 struct ipv6hdr *hdr; 179 180 /* Free reference early: we don't need it any more, 181 and it may hold ip_conntrack module loaded 182 indefinitely. */ 183 nf_reset(skb); 184 185 skb_postpull_rcsum(skb, skb->nh.raw, 186 skb->h.raw - skb->nh.raw); 187 hdr = skb->nh.ipv6h; 188 if (ipv6_addr_is_multicast(&hdr->daddr) && 189 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 190 &hdr->saddr) && 191 !ipv6_is_mld(skb, nexthdr)) 192 goto discard; 193 } 194 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 195 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 196 goto discard; 197 198 ret = ipprot->handler(&skb); 199 if (ret > 0) 200 goto resubmit; 201 else if (ret == 0) 202 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 203 } else { 204 if (!raw_sk) { 205 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 206 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS); 207 icmpv6_send(skb, ICMPV6_PARAMPROB, 208 ICMPV6_UNK_NEXTHDR, nhoff, 209 skb->dev); 210 } 211 } else 212 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 213 kfree_skb(skb); 214 } 215 rcu_read_unlock(); 216 return 0; 217 218 discard: 219 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 220 rcu_read_unlock(); 221 kfree_skb(skb); 222 return 0; 223 } 224 225 226 int ip6_input(struct sk_buff *skb) 227 { 228 return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish); 229 } 230 231 int ip6_mc_input(struct sk_buff *skb) 232 { 233 struct ipv6hdr *hdr; 234 int deliver; 235 236 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 237 238 hdr = skb->nh.ipv6h; 239 deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) || 240 ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 241 242 /* 243 * IPv6 multicast router mode isnt currently supported. 244 */ 245 #if 0 246 if (ipv6_config.multicast_route) { 247 int addr_type; 248 249 addr_type = ipv6_addr_type(&hdr->daddr); 250 251 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) { 252 struct sk_buff *skb2; 253 struct dst_entry *dst; 254 255 dst = skb->dst; 256 257 if (deliver) { 258 skb2 = skb_clone(skb, GFP_ATOMIC); 259 dst_output(skb2); 260 } else { 261 dst_output(skb); 262 return 0; 263 } 264 } 265 } 266 #endif 267 268 if (likely(deliver)) { 269 ip6_input(skb); 270 return 0; 271 } 272 /* discard */ 273 kfree_skb(skb); 274 275 return 0; 276 } 277