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 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 50 inline int ip6_rcv_finish( struct sk_buff *skb) 51 { 52 if (skb->dst == NULL) 53 ip6_route_input(skb); 54 55 return dst_input(skb); 56 } 57 58 int 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 64 if (dev->nd_net != &init_net) { 65 kfree_skb(skb); 66 return 0; 67 } 68 69 if (skb->pkt_type == PACKET_OTHERHOST) { 70 kfree_skb(skb); 71 return 0; 72 } 73 74 rcu_read_lock(); 75 76 idev = __in6_dev_get(skb->dev); 77 78 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES); 79 80 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) { 81 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 82 rcu_read_unlock(); 83 goto out; 84 } 85 86 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); 87 88 /* 89 * Store incoming device index. When the packet will 90 * be queued, we cannot refer to skb->dev anymore. 91 * 92 * BTW, when we send a packet for our own local address on a 93 * non-loopback interface (e.g. ethX), it is being delivered 94 * via the loopback interface (lo) here; skb->dev = loopback_dev. 95 * It, however, should be considered as if it is being 96 * arrived via the sending interface (ethX), because of the 97 * nature of scoping architecture. --yoshfuji 98 */ 99 IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex; 100 101 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) 102 goto err; 103 104 hdr = ipv6_hdr(skb); 105 106 if (hdr->version != 6) 107 goto err; 108 109 skb->transport_header = skb->network_header + sizeof(*hdr); 110 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 111 112 pkt_len = ntohs(hdr->payload_len); 113 114 /* pkt_len may be zero if Jumbo payload option is present */ 115 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { 116 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { 117 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS); 118 goto drop; 119 } 120 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { 121 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 122 goto drop; 123 } 124 hdr = ipv6_hdr(skb); 125 } 126 127 if (hdr->nexthdr == NEXTHDR_HOP) { 128 if (ipv6_parse_hopopts(skb) < 0) { 129 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 130 rcu_read_unlock(); 131 return 0; 132 } 133 } 134 135 rcu_read_unlock(); 136 137 return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL, 138 ip6_rcv_finish); 139 err: 140 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS); 141 drop: 142 rcu_read_unlock(); 143 kfree_skb(skb); 144 out: 145 return 0; 146 } 147 148 /* 149 * Deliver the packet to the host 150 */ 151 152 153 static int ip6_input_finish(struct sk_buff *skb) 154 { 155 struct inet6_protocol *ipprot; 156 unsigned int nhoff; 157 int nexthdr, raw; 158 u8 hash; 159 struct inet6_dev *idev; 160 161 /* 162 * Parse extension headers 163 */ 164 165 rcu_read_lock(); 166 resubmit: 167 idev = ip6_dst_idev(skb->dst); 168 if (!pskb_pull(skb, skb_transport_offset(skb))) 169 goto discard; 170 nhoff = IP6CB(skb)->nhoff; 171 nexthdr = skb_network_header(skb)[nhoff]; 172 173 raw = raw6_local_deliver(skb, nexthdr); 174 175 hash = nexthdr & (MAX_INET_PROTOS - 1); 176 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 177 int ret; 178 179 if (ipprot->flags & INET6_PROTO_FINAL) { 180 struct ipv6hdr *hdr; 181 182 /* Free reference early: we don't need it any more, 183 and it may hold ip_conntrack module loaded 184 indefinitely. */ 185 nf_reset(skb); 186 187 skb_postpull_rcsum(skb, skb_network_header(skb), 188 skb_network_header_len(skb)); 189 hdr = ipv6_hdr(skb); 190 if (ipv6_addr_is_multicast(&hdr->daddr) && 191 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 192 &hdr->saddr) && 193 !ipv6_is_mld(skb, nexthdr)) 194 goto discard; 195 } 196 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 197 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 198 goto discard; 199 200 ret = ipprot->handler(skb); 201 if (ret > 0) 202 goto resubmit; 203 else if (ret == 0) 204 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 205 } else { 206 if (!raw) { 207 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 208 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS); 209 icmpv6_send(skb, ICMPV6_PARAMPROB, 210 ICMPV6_UNK_NEXTHDR, nhoff, 211 skb->dev); 212 } 213 } else 214 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS); 215 kfree_skb(skb); 216 } 217 rcu_read_unlock(); 218 return 0; 219 220 discard: 221 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS); 222 rcu_read_unlock(); 223 kfree_skb(skb); 224 return 0; 225 } 226 227 228 int ip6_input(struct sk_buff *skb) 229 { 230 return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, 231 ip6_input_finish); 232 } 233 234 int ip6_mc_input(struct sk_buff *skb) 235 { 236 struct ipv6hdr *hdr; 237 int deliver; 238 239 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS); 240 241 hdr = ipv6_hdr(skb); 242 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 243 244 /* 245 * IPv6 multicast router mode isnt currently supported. 246 */ 247 #if 0 248 if (ipv6_config.multicast_route) { 249 int addr_type; 250 251 addr_type = ipv6_addr_type(&hdr->daddr); 252 253 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) { 254 struct sk_buff *skb2; 255 struct dst_entry *dst; 256 257 dst = skb->dst; 258 259 if (deliver) { 260 skb2 = skb_clone(skb, GFP_ATOMIC); 261 dst_output(skb2); 262 } else { 263 dst_output(skb); 264 return 0; 265 } 266 } 267 } 268 #endif 269 270 if (likely(deliver)) { 271 ip6_input(skb); 272 return 0; 273 } 274 /* discard */ 275 kfree_skb(skb); 276 277 return 0; 278 } 279