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/string.h>
  13 #include <net/inet_ecn.h>
  14 #include <net/ip.h>
  15 #include <net/ipv6.h>
  16 #include <net/xfrm.h>
  17
  18 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
  19 {
  20         struct ipv6hdr *outer_iph = skb->nh.ipv6h;
  21         struct ipv6hdr *inner_iph = skb->h.ipv6h;
  22
  23         if (INET_ECN_is_ce(ip6_get_dsfield(outer_iph)) &&
  24             INET_ECN_is_not_ce(ip6_get_dsfield(inner_iph)))
  25                 IP6_ECN_set_ce(inner_iph);
  26 }
  27
  28 int xfrm6_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
  29 {
  30         struct sk_buff *skb = *pskb;
  31         int err;
  32         u32 spi, seq;
  33         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
  34         struct xfrm_state *x;
  35         int xfrm_nr = 0;
  36         int decaps = 0;
  37         int nexthdr;
  38         unsigned int nhoff;
  39
  40         nhoff = *nhoffp;
  41         nexthdr = skb->nh.raw[nhoff];
  42
  43         if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  44                 goto drop;
  45
  46         do {
  47                 struct ipv6hdr *iph = skb->nh.ipv6h;
  48
  49                 if (xfrm_nr == XFRM_MAX_DEPTH)
  50                         goto drop;
  51
  52                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  53                 if (x == NULL)
  54                         goto drop;
  55                 spin_lock(&x->lock);
  56                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  57                         goto drop_unlock;
  58
  59                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  60                         goto drop_unlock;
  61
  62                 if (xfrm_state_check_expire(x))
  63                         goto drop_unlock;
  64
  65                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
  66                 if (nexthdr <= 0)
  67                         goto drop_unlock;
  68
  69                 skb->nh.raw[nhoff] = nexthdr;
  70
  71                 if (x->props.replay_window)
  72                         xfrm_replay_advance(x, seq);
  73
  74                 x->curlft.bytes += skb->len;
  75                 x->curlft.packets++;
  76
  77                 spin_unlock(&x->lock);
  78
  79                 xfrm_vec[xfrm_nr++].xvec = x;
  80
  81                 if (x->props.mode) { /* XXX */
  82                         if (nexthdr != IPPROTO_IPV6)
  83                                 goto drop;
  84                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  85                                 goto drop;
  86                         if (skb_cloned(skb) &&
  87                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
  88                                 goto drop;
  89                         if (!(x->props.flags & XFRM_STATE_NOECN))
  90                                 ipip6_ecn_decapsulate(skb);
  91                         skb->mac.raw = memmove(skb->data - skb->mac_len,
  92                                                skb->mac.raw, skb->mac_len);
  93                         skb->nh.raw = skb->data;
  94                         decaps = 1;
  95                         break;
  96                 }
  97
  98                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  99                         goto drop;
 100         } while (!err);
 101
 102         /* Allocate new secpath or COW existing one. */
 103         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 104                 struct sec_path *sp;
 105                 sp = secpath_dup(skb->sp);
 106                 if (!sp)
 107                         goto drop;
 108                 if (skb->sp)
 109                         secpath_put(skb->sp);
 110                 skb->sp = sp;
 111         }
 112
 113         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
 114                 goto drop;
 115
 116         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
 117         skb->sp->len += xfrm_nr;
 118         skb->ip_summed = CHECKSUM_NONE;
 119
 120         if (decaps) {
 121                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 122                         dst_release(skb->dst);
 123                         skb->dst = NULL;
 124                 }
 125                 netif_rx(skb);
 126                 return -1;
 127         } else {
 128                 return 1;
 129         }
 130
 131 drop_unlock:
 132         spin_unlock(&x->lock);
 133         xfrm_state_put(x);
 134 drop:
 135         while (--xfrm_nr >= 0)
 136                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
 137         kfree_skb(skb);
 138         return -1;
 139 }