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 static 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 64 if (skb->pkt_type == PACKET_OTHERHOST) 65 goto drop; 66 67 IP6_INC_STATS_BH(IPSTATS_MIB_INRECEIVES); 68 69 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) { 70 IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS); 71 goto out; 72 } 73 74 /* 75 * Store incoming device index. When the packet will 76 * be queued, we cannot refer to skb->dev anymore. 77 * 78 * BTW, when we send a packet for our own local address on a 79 * non-loopback interface (e.g. ethX), it is being delivered 80 * via the loopback interface (lo) here; skb->dev = &loopback_dev. 81 * It, however, should be considered as if it is being 82 * arrived via the sending interface (ethX), because of the 83 * nature of scoping architecture. --yoshfuji 84 */ 85 IP6CB(skb)->iif = skb->dst ? ((struct rt6_info *)skb->dst)->rt6i_idev->dev->ifindex : dev->ifindex; 86 87 if (skb->len < sizeof(struct ipv6hdr)) 88 goto err; 89 90 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) { 91 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 92 goto drop; 93 } 94 95 hdr = skb->nh.ipv6h; 96 97 if (hdr->version != 6) 98 goto err; 99 100 pkt_len = ntohs(hdr->payload_len); 101 102 /* pkt_len may be zero if Jumbo payload option is present */ 103 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 104 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) 105 goto truncated; 106 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 107 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 108 goto drop; 109 } 110 hdr = skb->nh.ipv6h; 111 } 112 113 if (hdr->nexthdr == NEXTHDR_HOP) { 114 skb->h.raw = (u8*)(hdr+1); 115 if (ipv6_parse_hopopts(skb, offsetof(struct ipv6hdr, nexthdr)) < 0) { 116 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 117 return 0; 118 } 119 hdr = skb->nh.ipv6h; 120 } 121 122 return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish); 123 truncated: 124 IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS); 125 err: 126 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 127 drop: 128 kfree_skb(skb); 129 out: 130 return 0; 131 } 132 133 /* 134 * Deliver the packet to the host 135 */ 136 137 138 static inline int ip6_input_finish(struct sk_buff *skb) 139 { 140 struct inet6_protocol *ipprot; 141 struct sock *raw_sk; 142 unsigned int nhoff; 143 int nexthdr; 144 u8 hash; 145 146 skb->h.raw = skb->nh.raw + sizeof(struct ipv6hdr); 147 148 /* 149 * Parse extension headers 150 */ 151 152 nexthdr = skb->nh.ipv6h->nexthdr; 153 nhoff = offsetof(struct ipv6hdr, nexthdr); 154 155 /* Skip hop-by-hop options, they are already parsed. */ 156 if (nexthdr == NEXTHDR_HOP) { 157 nhoff = sizeof(struct ipv6hdr); 158 nexthdr = skb->h.raw[0]; 159 skb->h.raw += (skb->h.raw[1]+1)<<3; 160 } 161 162 rcu_read_lock(); 163 resubmit: 164 if (!pskb_pull(skb, skb->h.raw - skb->data)) 165 goto discard; 166 nexthdr = skb->nh.raw[nhoff]; 167 168 raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]); 169 if (raw_sk && !ipv6_raw_deliver(skb, nexthdr)) 170 raw_sk = NULL; 171 172 hash = nexthdr & (MAX_INET_PROTOS - 1); 173 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 174 int ret; 175 176 if (ipprot->flags & INET6_PROTO_FINAL) { 177 struct ipv6hdr *hdr; 178 179 /* Free reference early: we don't need it any more, 180 and it may hold ip_conntrack module loaded 181 indefinitely. */ 182 nf_reset(skb); 183 184 skb_postpull_rcsum(skb, skb->nh.raw, 185 skb->h.raw - skb->nh.raw); 186 hdr = skb->nh.ipv6h; 187 if (ipv6_addr_is_multicast(&hdr->daddr) && 188 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 189 &hdr->saddr) && 190 !ipv6_is_mld(skb, nexthdr)) 191 goto discard; 192 } 193 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 194 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 195 goto discard; 196 197 ret = ipprot->handler(&skb, &nhoff); 198 if (ret > 0) 199 goto resubmit; 200 else if (ret == 0) 201 IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS); 202 } else { 203 if (!raw_sk) { 204 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 205 IP6_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS); 206 icmpv6_send(skb, ICMPV6_PARAMPROB, 207 ICMPV6_UNK_NEXTHDR, nhoff, 208 skb->dev); 209 } 210 } else 211 IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS); 212 kfree_skb(skb); 213 } 214 rcu_read_unlock(); 215 return 0; 216 217 discard: 218 IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS); 219 rcu_read_unlock(); 220 kfree_skb(skb); 221 return 0; 222 } 223 224 225 int ip6_input(struct sk_buff *skb) 226 { 227 return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, 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(IPSTATS_MIB_INMCASTPKTS); 236 237 hdr = skb->nh.ipv6h; 238 deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) || 239 ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 240 241 /* 242 * IPv6 multicast router mode isnt currently supported. 243 */ 244 #if 0 245 if (ipv6_config.multicast_route) { 246 int addr_type; 247 248 addr_type = ipv6_addr_type(&hdr->daddr); 249 250 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) { 251 struct sk_buff *skb2; 252 struct dst_entry *dst; 253 254 dst = skb->dst; 255 256 if (deliver) { 257 skb2 = skb_clone(skb, GFP_ATOMIC); 258 dst_output(skb2); 259 } else { 260 dst_output(skb); 261 return 0; 262 } 263 } 264 } 265 #endif 266 267 if (likely(deliver)) { 268 ip6_input(skb); 269 return 0; 270 } 271 /* discard */ 272 kfree_skb(skb); 273 274 return 0; 275 } 276