net/ipv6/xfrm6_input.c

   1 /*
   2  * xfrm6_input.c: based on net/ipv4/xfrm4_input.c
   3  *
   4  * Authors:
   5  *      Mitsuru KANDA @USAGI
   6  *      Kazunori MIYAZAWA @USAGI
   7  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
   8  *      YOSHIFUJI Hideaki @USAGI
   9  *              IPv6 support
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/string.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/netfilter_ipv6.h>
  16 #include <net/ipv6.h>
  17 #include <net/xfrm.h>
  18
  19 int xfrm6_rcv_spi(struct sk_buff *skb, u32 spi)
  20 {
  21         int err;
  22         u32 seq;
  23         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
  24         struct xfrm_state *x;
  25         int xfrm_nr = 0;
  26         int decaps = 0;
  27         int nexthdr;
  28         unsigned int nhoff;
  29
  30         nhoff = IP6CB(skb)->nhoff;
  31         nexthdr = skb->nh.raw[nhoff];
  32
  33         seq = 0;
  34         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  35                 goto drop;
  36
  37         do {
  38                 struct ipv6hdr *iph = skb->nh.ipv6h;
  39
  40                 if (xfrm_nr == XFRM_MAX_DEPTH)
  41                         goto drop;
  42
  43                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  44                 if (x == NULL)
  45                         goto drop;
  46                 spin_lock(&x->lock);
  47                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  48                         goto drop_unlock;
  49
  50                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  51                         goto drop_unlock;
  52
  53                 if (xfrm_state_check_expire(x))
  54                         goto drop_unlock;
  55
  56                 nexthdr = x->type->input(x, skb);
  57                 if (nexthdr <= 0)
  58                         goto drop_unlock;
  59
  60                 skb->nh.raw[nhoff] = nexthdr;
  61
  62                 if (x->props.replay_window)
  63                         xfrm_replay_advance(x, seq);
  64
  65                 x->curlft.bytes += skb->len;
  66                 x->curlft.packets++;
  67
  68                 spin_unlock(&x->lock);
  69
  70                 xfrm_vec[xfrm_nr++] = x;
  71
  72                 if (x->mode->input(x, skb))
  73                         goto drop;
  74
  75                 if (x->props.mode == XFRM_MODE_TUNNEL) { /* XXX */
  76                         decaps = 1;
  77                         break;
  78                 }
  79
  80                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  81                         goto drop;
  82         } while (!err);
  83
  84         /* Allocate new secpath or COW existing one. */
  85         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  86                 struct sec_path *sp;
  87                 sp = secpath_dup(skb->sp);
  88                 if (!sp)
  89                         goto drop;
  90                 if (skb->sp)
  91                         secpath_put(skb->sp);
  92                 skb->sp = sp;
  93         }
  94
  95         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
  96                 goto drop;
  97
  98         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
  99                xfrm_nr * sizeof(xfrm_vec[0]));
 100         skb->sp->len += xfrm_nr;
 101         skb->ip_summed = CHECKSUM_NONE;
 102
 103         nf_reset(skb);
 104
 105         if (decaps) {
 106                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 107                         dst_release(skb->dst);
 108                         skb->dst = NULL;
 109                 }
 110                 netif_rx(skb);
 111                 return -1;
 112         } else {
 113 #ifdef CONFIG_NETFILTER
 114                 skb->nh.ipv6h->payload_len = htons(skb->len);
 115                 __skb_push(skb, skb->data - skb->nh.raw);
 116
 117                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
 118                         ip6_rcv_finish);
 119                 return -1;
 120 #else
 121                 return 1;
 122 #endif
 123         }
 124
 125 drop_unlock:
 126         spin_unlock(&x->lock);
 127         xfrm_state_put(x);
 128 drop:
 129         while (--xfrm_nr >= 0)
 130                 xfrm_state_put(xfrm_vec[xfrm_nr]);
 131         kfree_skb(skb);
 132         return -1;
 133 }
 134
 135 EXPORT_SYMBOL(xfrm6_rcv_spi);
 136
 137 int xfrm6_rcv(struct sk_buff **pskb)
 138 {
 139         return xfrm6_rcv_spi(*pskb, 0);
 140 }