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 <net/inet_ecn.h>
  13 #include <net/ip.h>
  14 #include <net/ipv6.h>
  15 #include <net/xfrm.h>
  16
  17 static inline void ipip6_ecn_decapsulate(struct ipv6hdr *iph,
  18                                          struct sk_buff *skb)
  19 {
  20         if (INET_ECN_is_ce(ip6_get_dsfield(iph)) &&
  21             INET_ECN_is_not_ce(ip6_get_dsfield(skb->nh.ipv6h)))
  22                 IP6_ECN_set_ce(skb->nh.ipv6h);
  23 }
  24
  25 int xfrm6_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
  26 {
  27         struct sk_buff *skb = *pskb;
  28         int err;
  29         u32 spi, seq;
  30         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
  31         struct xfrm_state *x;
  32         int xfrm_nr = 0;
  33         int decaps = 0;
  34         int nexthdr = 0;
  35         u8 *prevhdr = NULL;
  36
  37         ip6_find_1stfragopt(skb, &prevhdr);
  38         nexthdr = *prevhdr;
  39         *nhoffp = prevhdr - skb->nh.raw;
  40
  41         if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  42                 goto drop;
  43
  44         do {
  45                 struct ipv6hdr *iph = skb->nh.ipv6h;
  46
  47                 if (xfrm_nr == XFRM_MAX_DEPTH)
  48                         goto drop;
  49
  50                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  51                 if (x == NULL)
  52                         goto drop;
  53                 spin_lock(&x->lock);
  54                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  55                         goto drop_unlock;
  56
  57                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  58                         goto drop_unlock;
  59
  60                 if (xfrm_state_check_expire(x))
  61                         goto drop_unlock;
  62
  63                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
  64                 if (nexthdr <= 0)
  65                         goto drop_unlock;
  66
  67                 if (x->props.replay_window)
  68                         xfrm_replay_advance(x, seq);
  69
  70                 x->curlft.bytes += skb->len;
  71                 x->curlft.packets++;
  72
  73                 spin_unlock(&x->lock);
  74
  75                 xfrm_vec[xfrm_nr++].xvec = x;
  76
  77                 if (x->props.mode) { /* XXX */
  78                         if (nexthdr != IPPROTO_IPV6)
  79                                 goto drop;
  80                         skb->nh.raw = skb->data;
  81                         if (!(x->props.flags & XFRM_STATE_NOECN))
  82                                 ipip6_ecn_decapsulate(iph, skb);
  83                         iph = skb->nh.ipv6h;
  84                         decaps = 1;
  85                         break;
  86                 }
  87
  88                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  89                         goto drop;
  90         } while (!err);
  91
  92         /* Allocate new secpath or COW existing one. */
  93         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  94                 struct sec_path *sp;
  95                 sp = secpath_dup(skb->sp);
  96                 if (!sp)
  97                         goto drop;
  98                 if (skb->sp)
  99                         secpath_put(skb->sp);
 100                 skb->sp = sp;
 101         }
 102
 103         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
 104                 goto drop;
 105
 106         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
 107         skb->sp->len += xfrm_nr;
 108         skb->ip_summed = CHECKSUM_NONE;
 109
 110         if (decaps) {
 111                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 112                         dst_release(skb->dst);
 113                         skb->dst = NULL;
 114                 }
 115                 netif_rx(skb);
 116                 return -1;
 117         } else {
 118                 return 1;
 119         }
 120
 121 drop_unlock:
 122         spin_unlock(&x->lock);
 123         xfrm_state_put(x);
 124 drop:
 125         while (--xfrm_nr >= 0)
 126                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
 127         kfree_skb(skb);
 128         return -1;
 129 }