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 static 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)
  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         /* Store incoming device index. When the packet will
  75            be queued, we cannot refer to skb->dev anymore.
  76          */
  77         IP6CB(skb)->iif = dev->ifindex;
  78
  79         if (skb->len < sizeof(struct ipv6hdr))
  80                 goto err;
  81
  82         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) {
  83                 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
  84                 goto drop;
  85         }
  86
  87         hdr = skb->nh.ipv6h;
  88
  89         if (hdr->version != 6)
  90                 goto err;
  91
  92         pkt_len = ntohs(hdr->payload_len);
  93
  94         /* pkt_len may be zero if Jumbo payload option is present */
  95         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
  96                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
  97                         goto truncated;
  98                 if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
  99                         if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr))){
 100                                 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
 101                                 goto drop;
 102                         }
 103                         hdr = skb->nh.ipv6h;
 104                         if (skb->ip_summed == CHECKSUM_HW)
 105                                 skb->ip_summed = CHECKSUM_NONE;
 106                 }
 107         }
 108
 109         if (hdr->nexthdr == NEXTHDR_HOP) {
 110                 skb->h.raw = (u8*)(hdr+1);
 111                 if (ipv6_parse_hopopts(skb, offsetof(struct ipv6hdr, nexthdr)) < 0) {
 112                         IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
 113                         return 0;
 114                 }
 115                 hdr = skb->nh.ipv6h;
 116         }
 117
 118         return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
 119 truncated:
 120         IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS);
 121 err:
 122         IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
 123 drop:
 124         kfree_skb(skb);
 125 out:
 126         return 0;
 127 }
 128
 129 /*
 130  *      Deliver the packet to the host
 131  */
 132
 133
 134 static inline int ip6_input_finish(struct sk_buff *skb)
 135 {
 136         struct inet6_protocol *ipprot;
 137         struct sock *raw_sk;
 138         unsigned int nhoff;
 139         int nexthdr;
 140         u8 hash;
 141         int cksum_sub = 0;
 142
 143         skb->h.raw = skb->nh.raw + sizeof(struct ipv6hdr);
 144
 145         /*
 146          *      Parse extension headers
 147          */
 148
 149         nexthdr = skb->nh.ipv6h->nexthdr;
 150         nhoff = offsetof(struct ipv6hdr, nexthdr);
 151
 152         /* Skip hop-by-hop options, they are already parsed. */
 153         if (nexthdr == NEXTHDR_HOP) {
 154                 nhoff = sizeof(struct ipv6hdr);
 155                 nexthdr = skb->h.raw[0];
 156                 skb->h.raw += (skb->h.raw[1]+1)<<3;
 157         }
 158
 159         rcu_read_lock();
 160 resubmit:
 161         if (!pskb_pull(skb, skb->h.raw - skb->data))
 162                 goto discard;
 163         nexthdr = skb->nh.raw[nhoff];
 164
 165         raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
 166         if (raw_sk)
 167                 ipv6_raw_deliver(skb, nexthdr);
 168
 169         hash = nexthdr & (MAX_INET_PROTOS - 1);
 170         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
 171                 int ret;
 172
 173                 if (ipprot->flags & INET6_PROTO_FINAL) {
 174                         struct ipv6hdr *hdr;
 175
 176                         if (!cksum_sub && skb->ip_summed == CHECKSUM_HW) {
 177                                 skb->csum = csum_sub(skb->csum,
 178                                                      csum_partial(skb->nh.raw, skb->h.raw-skb->nh.raw, 0));
 179                                 cksum_sub++;
 180                         }
 181                         hdr = skb->nh.ipv6h;
 182                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
 183                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
 184                             &hdr->saddr) &&
 185                             !ipv6_is_mld(skb, nexthdr))
 186                                 goto discard;
 187                 }
 188                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
 189                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
 190                         goto discard;
 191
 192                 ret = ipprot->handler(&skb, &nhoff);
 193                 if (ret > 0)
 194                         goto resubmit;
 195                 else if (ret == 0)
 196                         IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
 197         } else {
 198                 if (!raw_sk) {
 199                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 200                                 IP6_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
 201                                 icmpv6_param_prob(skb, ICMPV6_UNK_NEXTHDR, nhoff);
 202                         }
 203                 } else {
 204                         IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
 205                         kfree_skb(skb);
 206                 }
 207         }
 208         rcu_read_unlock();
 209         return 0;
 210
 211 discard:
 212         IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
 213         rcu_read_unlock();
 214         kfree_skb(skb);
 215         return 0;
 216 }
 217
 218
 219 int ip6_input(struct sk_buff *skb)
 220 {
 221         return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish);
 222 }
 223
 224 int ip6_mc_input(struct sk_buff *skb)
 225 {
 226         struct ipv6hdr *hdr;
 227         int deliver;
 228
 229         IP6_INC_STATS_BH(IPSTATS_MIB_INMCASTPKTS);
 230
 231         hdr = skb->nh.ipv6h;
 232         deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
 233             ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 234
 235         /*
 236          *      IPv6 multicast router mode isnt currently supported.
 237          */
 238 #if 0
 239         if (ipv6_config.multicast_route) {
 240                 int addr_type;
 241
 242                 addr_type = ipv6_addr_type(&hdr->daddr);
 243
 244                 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
 245                         struct sk_buff *skb2;
 246                         struct dst_entry *dst;
 247
 248                         dst = skb->dst;
 249
 250                         if (deliver) {
 251                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 252                                 dst_output(skb2);
 253                         } else {
 254                                 dst_output(skb);
 255                                 return 0;
 256                         }
 257                 }
 258         }
 259 #endif
 260
 261         if (likely(deliver)) {
 262                 ip6_input(skb);
 263                 return 0;
 264         }
 265         /* discard */
 266         kfree_skb(skb);
 267
 268         return 0;
 269 }