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 (skb->pkt_type == PACKET_OTHERHOST) {
  65                 kfree_skb(skb);
  66                 return 0;
  67         }
  68
  69         rcu_read_lock();
  70
  71         idev = __in6_dev_get(skb->dev);
  72
  73         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);
  74
  75         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
  76                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
  77                 rcu_read_unlock();
  78                 goto out;
  79         }
  80
  81         memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
  82
  83         /*
  84          * Store incoming device index. When the packet will
  85          * be queued, we cannot refer to skb->dev anymore.
  86          *
  87          * BTW, when we send a packet for our own local address on a
  88          * non-loopback interface (e.g. ethX), it is being delivered
  89          * via the loopback interface (lo) here; skb->dev = &loopback_dev.
  90          * It, however, should be considered as if it is being
  91          * arrived via the sending interface (ethX), because of the
  92          * nature of scoping architecture. --yoshfuji
  93          */
  94         IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
  95
  96         if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
  97                 goto err;
  98
  99         hdr = ipv6_hdr(skb);
 100
 101         if (hdr->version != 6)
 102                 goto err;
 103
 104         skb->transport_header = skb->network_header + sizeof(*hdr);
 105         IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 106
 107         pkt_len = ntohs(hdr->payload_len);
 108
 109         /* pkt_len may be zero if Jumbo payload option is present */
 110         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
 111                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
 112                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 113                         goto drop;
 114                 }
 115                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
 116                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 117                         goto drop;
 118                 }
 119                 hdr = ipv6_hdr(skb);
 120         }
 121
 122         if (hdr->nexthdr == NEXTHDR_HOP) {
 123                 if (ipv6_parse_hopopts(&skb) < 0) {
 124                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 125                         rcu_read_unlock();
 126                         return 0;
 127                 }
 128         }
 129
 130         rcu_read_unlock();
 131
 132         return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
 133 err:
 134         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
 135 drop:
 136         rcu_read_unlock();
 137         kfree_skb(skb);
 138 out:
 139         return 0;
 140 }
 141
 142 /*
 143  *      Deliver the packet to the host
 144  */
 145
 146
 147 static inline int ip6_input_finish(struct sk_buff *skb)
 148 {
 149         struct inet6_protocol *ipprot;
 150         struct sock *raw_sk;
 151         unsigned int nhoff;
 152         int nexthdr;
 153         u8 hash;
 154         struct inet6_dev *idev;
 155
 156         /*
 157          *      Parse extension headers
 158          */
 159
 160         rcu_read_lock();
 161 resubmit:
 162         idev = ip6_dst_idev(skb->dst);
 163         if (!pskb_pull(skb, skb_transport_offset(skb)))
 164                 goto discard;
 165         nhoff = IP6CB(skb)->nhoff;
 166         nexthdr = skb_network_header(skb)[nhoff];
 167
 168         raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
 169         if (raw_sk && !ipv6_raw_deliver(skb, nexthdr))
 170                 raw_sk = NULL;
 171
 172         hash = nexthdr & (MAX_INET_PROTOS - 1);
 173         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
 174                 int ret;
 175
 176                 if (ipprot->flags & INET6_PROTO_FINAL) {
 177                         struct ipv6hdr *hdr;
 178
 179                         /* Free reference early: we don't need it any more,
 180                            and it may hold ip_conntrack module loaded
 181                            indefinitely. */
 182                         nf_reset(skb);
 183
 184                         skb_postpull_rcsum(skb, skb_network_header(skb),
 185                                            skb_network_header_len(skb));
 186                         hdr = ipv6_hdr(skb);
 187                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
 188                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
 189                             &hdr->saddr) &&
 190                             !ipv6_is_mld(skb, nexthdr))
 191                                 goto discard;
 192                 }
 193                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
 194                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 195                         goto discard;
 196
 197                 ret = ipprot->handler(&skb);
 198                 if (ret > 0)
 199                         goto resubmit;
 200                 else if (ret == 0)
 201                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 202         } else {
 203                 if (!raw_sk) {
 204                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 205                                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
 206                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
 207                                             ICMPV6_UNK_NEXTHDR, nhoff,
 208                                             skb->dev);
 209                         }
 210                 } else
 211                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
 212                 kfree_skb(skb);
 213         }
 214         rcu_read_unlock();
 215         return 0;
 216
 217 discard:
 218         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
 219         rcu_read_unlock();
 220         kfree_skb(skb);
 221         return 0;
 222 }
 223
 224
 225 int ip6_input(struct sk_buff *skb)
 226 {
 227         return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish);
 228 }
 229
 230 int ip6_mc_input(struct sk_buff *skb)
 231 {
 232         struct ipv6hdr *hdr;
 233         int deliver;
 234
 235         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
 236
 237         hdr = ipv6_hdr(skb);
 238         deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
 239             ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 240
 241         /*
 242          *      IPv6 multicast router mode isnt currently supported.
 243          */
 244 #if 0
 245         if (ipv6_config.multicast_route) {
 246                 int addr_type;
 247
 248                 addr_type = ipv6_addr_type(&hdr->daddr);
 249
 250                 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
 251                         struct sk_buff *skb2;
 252                         struct dst_entry *dst;
 253
 254                         dst = skb->dst;
 255
 256                         if (deliver) {
 257                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 258                                 dst_output(skb2);
 259                         } else {
 260                                 dst_output(skb);
 261                                 return 0;
 262                         }
 263                 }
 264         }
 265 #endif
 266
 267         if (likely(deliver)) {
 268                 ip6_input(skb);
 269                 return 0;
 270         }
 271         /* discard */
 272         kfree_skb(skb);
 273
 274         return 0;
 275 }