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/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         struct sock *raw_sk;
 157         unsigned int nhoff;
 158         int nexthdr;
 159         u8 hash;
 160         struct inet6_dev *idev;
 161
 162         /*
 163          *      Parse extension headers
 164          */
 165
 166         rcu_read_lock();
 167 resubmit:
 168         idev = ip6_dst_idev(skb->dst);
 169         if (!pskb_pull(skb, skb_transport_offset(skb)))
 170                 goto discard;
 171         nhoff = IP6CB(skb)->nhoff;
 172         nexthdr = skb_network_header(skb)[nhoff];
 173
 174         raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
 175         if (raw_sk && !ipv6_raw_deliver(skb, nexthdr))
 176                 raw_sk = NULL;
 177
 178         hash = nexthdr & (MAX_INET_PROTOS - 1);
 179         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
 180                 int ret;
 181
 182                 if (ipprot->flags & INET6_PROTO_FINAL) {
 183                         struct ipv6hdr *hdr;
 184
 185                         /* Free reference early: we don't need it any more,
 186                            and it may hold ip_conntrack module loaded
 187                            indefinitely. */
 188                         nf_reset(skb);
 189
 190                         skb_postpull_rcsum(skb, skb_network_header(skb),
 191                                            skb_network_header_len(skb));
 192                         hdr = ipv6_hdr(skb);
 193                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
 194                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
 195                             &hdr->saddr) &&
 196                             !ipv6_is_mld(skb, nexthdr))
 197                                 goto discard;
 198                 }
 199                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
 200                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 201                         goto discard;
 202
 203                 ret = ipprot->handler(skb);
 204                 if (ret > 0)
 205                         goto resubmit;
 206                 else if (ret == 0)
 207                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 208         } else {
 209                 if (!raw_sk) {
 210                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 211                                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
 212                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
 213                                             ICMPV6_UNK_NEXTHDR, nhoff,
 214                                             skb->dev);
 215                         }
 216                 } else
 217                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 218                 kfree_skb(skb);
 219         }
 220         rcu_read_unlock();
 221         return 0;
 222
 223 discard:
 224         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
 225         rcu_read_unlock();
 226         kfree_skb(skb);
 227         return 0;
 228 }
 229
 230
 231 int ip6_input(struct sk_buff *skb)
 232 {
 233         return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
 234                        ip6_input_finish);
 235 }
 236
 237 int ip6_mc_input(struct sk_buff *skb)
 238 {
 239         struct ipv6hdr *hdr;
 240         int deliver;
 241
 242         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
 243
 244         hdr = ipv6_hdr(skb);
 245         deliver = unlikely(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) ||
 246             ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 247
 248         /*
 249          *      IPv6 multicast router mode isnt currently supported.
 250          */
 251 #if 0
 252         if (ipv6_config.multicast_route) {
 253                 int addr_type;
 254
 255                 addr_type = ipv6_addr_type(&hdr->daddr);
 256
 257                 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
 258                         struct sk_buff *skb2;
 259                         struct dst_entry *dst;
 260
 261                         dst = skb->dst;
 262
 263                         if (deliver) {
 264                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 265                                 dst_output(skb2);
 266                         } else {
 267                                 dst_output(skb);
 268                                 return 0;
 269                         }
 270                 }
 271         }
 272 #endif
 273
 274         if (likely(deliver)) {
 275                 ip6_input(skb);
 276                 return 0;
 277         }
 278         /* discard */
 279         kfree_skb(skb);
 280
 281         return 0;
 282 }