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         struct inet6_dev *idev;
  64
  65         if (skb->pkt_type == PACKET_OTHERHOST) {
  66                 kfree_skb(skb);
  67                 return 0;
  68         }
  69
  70         rcu_read_lock();
  71
  72         idev = __in6_dev_get(skb->dev);
  73
  74         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);
  75
  76         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
  77                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
  78                 rcu_read_unlock();
  79                 goto out;
  80         }
  81
  82         memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
  83
  84         /*
  85          * Store incoming device index. When the packet will
  86          * be queued, we cannot refer to skb->dev anymore.
  87          *
  88          * BTW, when we send a packet for our own local address on a
  89          * non-loopback interface (e.g. ethX), it is being delivered
  90          * via the loopback interface (lo) here; skb->dev = &loopback_dev.
  91          * It, however, should be considered as if it is being
  92          * arrived via the sending interface (ethX), because of the
  93          * nature of scoping architecture. --yoshfuji
  94          */
  95         IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
  96
  97         if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
  98                 goto err;
  99
 100         hdr = skb->nh.ipv6h;
 101
 102         if (hdr->version != 6)
 103                 goto err;
 104
 105         skb->h.raw = (u8 *)(hdr + 1);
 106         IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 107
 108         pkt_len = ntohs(hdr->payload_len);
 109
 110         /* pkt_len may be zero if Jumbo payload option is present */
 111         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
 112                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
 113                         goto truncated;
 114                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
 115                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 116                         goto drop;
 117                 }
 118                 hdr = skb->nh.ipv6h;
 119         }
 120
 121         if (hdr->nexthdr == NEXTHDR_HOP) {
 122                 if (ipv6_parse_hopopts(&skb) < 0) {
 123                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 124                         rcu_read_unlock();
 125                         return 0;
 126                 }
 127         }
 128
 129         rcu_read_unlock();
 130
 131         return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
 132 truncated:
 133         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 134 err:
 135         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 136 drop:
 137         rcu_read_unlock();
 138         kfree_skb(skb);
 139 out:
 140         return 0;
 141 }
 142
 143 /*
 144  *      Deliver the packet to the host
 145  */
 146
 147
 148 static inline int ip6_input_finish(struct sk_buff *skb)
 149 {
 150         struct inet6_protocol *ipprot;
 151         struct sock *raw_sk;
 152         unsigned int nhoff;
 153         int nexthdr;
 154         u8 hash;
 155         struct inet6_dev *idev;
 156
 157         /*
 158          *      Parse extension headers
 159          */
 160
 161         rcu_read_lock();
 162 resubmit:
 163         idev = ip6_dst_idev(skb->dst);
 164         if (!pskb_pull(skb, skb->h.raw - skb->data))
 165                 goto discard;
 166         nhoff = IP6CB(skb)->nhoff;
 167         nexthdr = skb->nh.raw[nhoff];
 168
 169         raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
 170         if (raw_sk && !ipv6_raw_deliver(skb, nexthdr))
 171                 raw_sk = NULL;
 172
 173         hash = nexthdr & (MAX_INET_PROTOS - 1);
 174         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
 175                 int ret;
 176
 177                 if (ipprot->flags & INET6_PROTO_FINAL) {
 178                         struct ipv6hdr *hdr;
 179
 180                         /* Free reference early: we don't need it any more,
 181                            and it may hold ip_conntrack module loaded
 182                            indefinitely. */
 183                         nf_reset(skb);
 184
 185                         skb_postpull_rcsum(skb, skb->nh.raw,
 186                                            skb->h.raw - skb->nh.raw);
 187                         hdr = skb->nh.ipv6h;
 188                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
 189                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
 190                             &hdr->saddr) &&
 191                             !ipv6_is_mld(skb, nexthdr))
 192                                 goto discard;
 193                 }
 194                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
 195                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 196                         goto discard;
 197
 198                 ret = ipprot->handler(&skb);
 199                 if (ret > 0)
 200                         goto resubmit;
 201                 else if (ret == 0)
 202                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 203         } else {
 204                 if (!raw_sk) {
 205                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 206                                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
 207                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
 208                                             ICMPV6_UNK_NEXTHDR, nhoff,
 209                                             skb->dev);
 210                         }
 211                 } else
 212                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 213                 kfree_skb(skb);
 214         }
 215         rcu_read_unlock();
 216         return 0;
 217
 218 discard:
 219         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
 220         rcu_read_unlock();
 221         kfree_skb(skb);
 222         return 0;
 223 }
 224
 225
 226 int ip6_input(struct sk_buff *skb)
 227 {
 228         return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish);
 229 }
 230
 231 int ip6_mc_input(struct sk_buff *skb)
 232 {
 233         struct ipv6hdr *hdr;
 234         int deliver;
 235
 236         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
 237
 238         hdr = skb->nh.ipv6h;
 239         deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
 240             ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 241
 242         /*
 243          *      IPv6 multicast router mode isnt currently supported.
 244          */
 245 #if 0
 246         if (ipv6_config.multicast_route) {
 247                 int addr_type;
 248
 249                 addr_type = ipv6_addr_type(&hdr->daddr);
 250
 251                 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
 252                         struct sk_buff *skb2;
 253                         struct dst_entry *dst;
 254
 255                         dst = skb->dst;
 256
 257                         if (deliver) {
 258                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 259                                 dst_output(skb2);
 260                         } else {
 261                                 dst_output(skb);
 262                                 return 0;
 263                         }
 264                 }
 265         }
 266 #endif
 267
 268         if (likely(deliver)) {
 269                 ip6_input(skb);
 270                 return 0;
 271         }
 272         /* discard */
 273         kfree_skb(skb);
 274
 275         return 0;
 276 }