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 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 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); 75 76 /* 77 * Store incoming device index. When the packet will 78 * be queued, we cannot refer to skb->dev anymore. 79 * 80 * BTW, when we send a packet for our own local address on a 81 * non-loopback interface (e.g. ethX), it is being delivered 82 * via the loopback interface (lo) here; skb->dev = &loopback_dev. 83 * It, however, should be considered as if it is being 84 * arrived via the sending interface (ethX), because of the 85 * nature of scoping architecture. --yoshfuji 86 */ 87 IP6CB(skb)->iif = skb->dst ? ((struct rt6_info *)skb->dst)->rt6i_idev->dev->ifindex : dev->ifindex; 88 89 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr)))) 90 goto err; 91 92 hdr = skb->nh.ipv6h; 93 94 if (hdr->version != 6) 95 goto err; 96 97 skb->h.raw = (u8 *)(hdr + 1); 98 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 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 if (ipv6_parse_hopopts(skb) < 0) { 115 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 116 return 0; 117 } 118 } 119 120 return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish); 121 truncated: 122 IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS); 123 err: 124 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 125 drop: 126 kfree_skb(skb); 127 out: 128 return 0; 129 } 130 131 /* 132 * Deliver the packet to the host 133 */ 134 135 136 static inline int ip6_input_finish(struct sk_buff *skb) 137 { 138 struct inet6_protocol *ipprot; 139 struct sock *raw_sk; 140 unsigned int nhoff; 141 int nexthdr; 142 u8 hash; 143 144 /* 145 * Parse extension headers 146 */ 147 148 rcu_read_lock(); 149 resubmit: 150 if (!pskb_pull(skb, skb->h.raw - skb->data)) 151 goto discard; 152 nhoff = IP6CB(skb)->nhoff; 153 nexthdr = skb->nh.raw[nhoff]; 154 155 raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]); 156 if (raw_sk && !ipv6_raw_deliver(skb, nexthdr)) 157 raw_sk = NULL; 158 159 hash = nexthdr & (MAX_INET_PROTOS - 1); 160 if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { 161 int ret; 162 163 if (ipprot->flags & INET6_PROTO_FINAL) { 164 struct ipv6hdr *hdr; 165 166 /* Free reference early: we don't need it any more, 167 and it may hold ip_conntrack module loaded 168 indefinitely. */ 169 nf_reset(skb); 170 171 skb_postpull_rcsum(skb, skb->nh.raw, 172 skb->h.raw - skb->nh.raw); 173 hdr = skb->nh.ipv6h; 174 if (ipv6_addr_is_multicast(&hdr->daddr) && 175 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, 176 &hdr->saddr) && 177 !ipv6_is_mld(skb, nexthdr)) 178 goto discard; 179 } 180 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && 181 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) 182 goto discard; 183 184 ret = ipprot->handler(&skb); 185 if (ret > 0) 186 goto resubmit; 187 else if (ret == 0) 188 IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS); 189 } else { 190 if (!raw_sk) { 191 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 192 IP6_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS); 193 icmpv6_send(skb, ICMPV6_PARAMPROB, 194 ICMPV6_UNK_NEXTHDR, nhoff, 195 skb->dev); 196 } 197 } else 198 IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS); 199 kfree_skb(skb); 200 } 201 rcu_read_unlock(); 202 return 0; 203 204 discard: 205 IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS); 206 rcu_read_unlock(); 207 kfree_skb(skb); 208 return 0; 209 } 210 211 212 int ip6_input(struct sk_buff *skb) 213 { 214 return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish); 215 } 216 217 int ip6_mc_input(struct sk_buff *skb) 218 { 219 struct ipv6hdr *hdr; 220 int deliver; 221 222 IP6_INC_STATS_BH(IPSTATS_MIB_INMCASTPKTS); 223 224 hdr = skb->nh.ipv6h; 225 deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) || 226 ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); 227 228 /* 229 * IPv6 multicast router mode isnt currently supported. 230 */ 231 #if 0 232 if (ipv6_config.multicast_route) { 233 int addr_type; 234 235 addr_type = ipv6_addr_type(&hdr->daddr); 236 237 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) { 238 struct sk_buff *skb2; 239 struct dst_entry *dst; 240 241 dst = skb->dst; 242 243 if (deliver) { 244 skb2 = skb_clone(skb, GFP_ATOMIC); 245 dst_output(skb2); 246 } else { 247 dst_output(skb); 248 return 0; 249 } 250 } 251 } 252 #endif 253 254 if (likely(deliver)) { 255 ip6_input(skb); 256 return 0; 257 } 258 /* discard */ 259 kfree_skb(skb); 260 261 return 0; 262 } 263