net/ipv6/ip6_input.c

   1 /*
   2  *      IPv6 input
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <pedro_m@yahoo.com>
   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
  19 #include <linux/errno.h>
  20 #include <linux/types.h>
  21 #include <linux/socket.h>
  22 #include <linux/sockios.h>
  23 #include <linux/sched.h>
  24 #include <linux/net.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/in6.h>
  27 #include <linux/icmpv6.h>
  28
  29 #include <linux/netfilter.h>
  30 #include <linux/netfilter_ipv6.h>
  31
  32 #include <net/sock.h>
  33 #include <net/snmp.h>
  34
  35 #include <net/ipv6.h>
  36 #include <net/protocol.h>
  37 #include <net/transp_v6.h>
  38 #include <net/rawv6.h>
  39 #include <net/ndisc.h>
  40 #include <net/ip6_route.h>
  41 #include <net/addrconf.h>
  42
  43
  44
  45 static inline int ip6_rcv_finish( struct sk_buff *skb)
  46 {
  47         if (skb->dst == NULL)
  48                 ip6_route_input(skb);
  49
  50         return skb->dst->input(skb);
  51 }
  52
  53 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
  54 {
  55         struct ipv6hdr *hdr;
  56         u32             pkt_len;
  57
  58         if (skb->pkt_type == PACKET_OTHERHOST)
  59                 goto drop;
  60
  61         IP6_INC_STATS_BH(Ip6InReceives);
  62
  63         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
  64                 goto out;
  65
  66         /* Store incoming device index. When the packet will
  67            be queued, we cannot refer to skb->dev anymore.
  68          */
  69         ((struct inet6_skb_parm *)skb->cb)->iif = dev->ifindex;
  70
  71         if (skb->len < sizeof(struct ipv6hdr))
  72                 goto err;
  73
  74         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  75                 goto drop;
  76
  77         hdr = skb->nh.ipv6h;
  78
  79         if (hdr->version != 6)
  80                 goto err;
  81
  82         pkt_len = ntohs(hdr->payload_len);
  83
  84         /* pkt_len may be zero if Jumbo payload option is present */
  85         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
  86                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
  87                         goto truncated;
  88                 if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
  89                         if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr)))
  90                                 goto drop;
  91                         hdr = skb->nh.ipv6h;
  92                         if (skb->ip_summed == CHECKSUM_HW)
  93                                 skb->ip_summed = CHECKSUM_NONE;
  94                 }
  95         }
  96
  97         if (hdr->nexthdr == NEXTHDR_HOP) {
  98                 skb->h.raw = (u8*)(hdr+1);
  99                 if (ipv6_parse_hopopts(skb, offsetof(struct ipv6hdr, nexthdr)) < 0) {
 100                         IP6_INC_STATS_BH(Ip6InHdrErrors);
 101                         return 0;
 102                 }
 103                 hdr = skb->nh.ipv6h;
 104         }
 105
 106         return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
 107 truncated:
 108         IP6_INC_STATS_BH(Ip6InTruncatedPkts);
 109 err:
 110         IP6_INC_STATS_BH(Ip6InHdrErrors);
 111 drop:
 112         kfree_skb(skb);
 113 out:
 114         return 0;
 115 }
 116
 117 /*
 118  *      Deliver the packet to the host
 119  */
 120
 121
 122 static inline int ip6_input_finish(struct sk_buff *skb)
 123 {
 124         struct ipv6hdr *hdr = skb->nh.ipv6h;
 125         struct inet6_protocol *ipprot;
 126         struct sock *raw_sk;
 127         int nhoff;
 128         int nexthdr;
 129         int found = 0;
 130         u8 hash;
 131
 132         skb->h.raw = skb->nh.raw + sizeof(struct ipv6hdr);
 133
 134         /*
 135          *      Parse extension headers
 136          */
 137
 138         nexthdr = hdr->nexthdr;
 139         nhoff = offsetof(struct ipv6hdr, nexthdr);
 140
 141         /* Skip  hop-by-hop options, they are already parsed. */
 142         if (nexthdr == NEXTHDR_HOP) {
 143                 nhoff = sizeof(struct ipv6hdr);
 144                 nexthdr = skb->h.raw[0];
 145                 skb->h.raw += (skb->h.raw[1]+1)<<3;
 146         }
 147
 148         /* This check is sort of optimization.
 149            It would be stupid to detect for optional headers,
 150            which are missing with probability of 200%
 151          */
 152         if (nexthdr != IPPROTO_TCP && nexthdr != IPPROTO_UDP) {
 153                 nhoff = ipv6_parse_exthdrs(&skb, nhoff);
 154                 if (nhoff < 0)
 155                         return 0;
 156                 nexthdr = skb->nh.raw[nhoff];
 157                 hdr = skb->nh.ipv6h;
 158         }
 159
 160         if (!pskb_pull(skb, skb->h.raw - skb->data))
 161                 goto discard;
 162
 163         if (skb->ip_summed == CHECKSUM_HW)
 164                 skb->csum = csum_sub(skb->csum,
 165                                      csum_partial(skb->nh.raw, skb->h.raw-skb->nh.raw, 0));
 166
 167         raw_sk = raw_v6_htable[nexthdr&(MAX_INET_PROTOS-1)];
 168         if (raw_sk)
 169                 raw_sk = ipv6_raw_deliver(skb, nexthdr);
 170
 171         hash = nexthdr & (MAX_INET_PROTOS - 1);
 172         for (ipprot = (struct inet6_protocol *) inet6_protos[hash];
 173              ipprot != NULL;
 174              ipprot = (struct inet6_protocol *) ipprot->next) {
 175                 struct sk_buff *buff = skb;
 176
 177                 if (ipprot->protocol != nexthdr)
 178                         continue;
 179
 180                 if (ipprot->copy || raw_sk)
 181                         buff = skb_clone(skb, GFP_ATOMIC);
 182
 183                 if (buff)
 184                         ipprot->handler(buff);
 185                 found = 1;
 186         }
 187
 188         if (raw_sk) {
 189                 rawv6_rcv(raw_sk, skb);
 190                 sock_put(raw_sk);
 191                 found = 1;
 192         }
 193
 194         /*
 195          *      not found: send ICMP parameter problem back
 196          */
 197         if (!found) {
 198                 IP6_INC_STATS_BH(Ip6InUnknownProtos);
 199                 icmpv6_param_prob(skb, ICMPV6_UNK_NEXTHDR, nhoff);
 200         }
 201
 202         return 0;
 203
 204 discard:
 205         kfree_skb(skb);
 206         return 0;
 207 }
 208
 209
 210 int ip6_input(struct sk_buff *skb)
 211 {
 212         return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish);
 213 }
 214
 215 int ip6_mc_input(struct sk_buff *skb)
 216 {
 217         struct ipv6hdr *hdr;
 218         int deliver = 0;
 219         int discard = 1;
 220
 221         IP6_INC_STATS_BH(Ip6InMcastPkts);
 222
 223         hdr = skb->nh.ipv6h;
 224         if (ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, &hdr->saddr))
 225                 deliver = 1;
 226
 227         /*
 228          *      IPv6 multicast router mode isnt currently supported.
 229          */
 230 #if 0
 231         if (ipv6_config.multicast_route) {
 232                 int addr_type;
 233
 234                 addr_type = ipv6_addr_type(&hdr->daddr);
 235
 236                 if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
 237                         struct sk_buff *skb2;
 238                         struct dst_entry *dst;
 239
 240                         dst = skb->dst;
 241
 242                         if (deliver) {
 243                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 244                         } else {
 245                                 discard = 0;
 246                                 skb2 = skb;
 247                         }
 248
 249                         dst->output(skb2);
 250                 }
 251         }
 252 #endif
 253
 254         if (deliver) {
 255                 discard = 0;
 256                 ip6_input(skb);
 257         }
 258
 259         if (discard)
 260                 kfree_skb(skb);
 261
 262         return 0;
 263 }