net/ipv6/ip6_input.c

   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 }