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 = 0;
  38         u8 *prevhdr = NULL;
  39
  40         ip6_find_1stfragopt(skb, &prevhdr);
  41         nexthdr = *prevhdr;
  42         *nhoffp = prevhdr - skb->nh.raw;
  43
  44         if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  45                 goto drop;
  46
  47         do {
  48                 struct ipv6hdr *iph = skb->nh.ipv6h;
  49
  50                 if (xfrm_nr == XFRM_MAX_DEPTH)
  51                         goto drop;
  52
  53                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  54                 if (x == NULL)
  55                         goto drop;
  56                 spin_lock(&x->lock);
  57                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  58                         goto drop_unlock;
  59
  60                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  61                         goto drop_unlock;
  62
  63                 if (xfrm_state_check_expire(x))
  64                         goto drop_unlock;
  65
  66                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
  67                 if (nexthdr <= 0)
  68                         goto drop_unlock;
  69
  70                 if (x->props.replay_window)
  71                         xfrm_replay_advance(x, seq);
  72
  73                 x->curlft.bytes += skb->len;
  74                 x->curlft.packets++;
  75
  76                 spin_unlock(&x->lock);
  77
  78                 xfrm_vec[xfrm_nr++].xvec = x;
  79
  80                 if (x->props.mode) { /* XXX */
  81                         if (nexthdr != IPPROTO_IPV6)
  82                                 goto drop;
  83                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  84                                 goto drop;
  85                         if (skb_cloned(skb) &&
  86                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
  87                                 goto drop;
  88                         if (!(x->props.flags & XFRM_STATE_NOECN))
  89                                 ipip6_ecn_decapsulate(skb);
  90                         skb->mac.raw = memmove(skb->data - skb->mac_len,
  91                                                skb->mac.raw, skb->mac_len);
  92                         skb->nh.raw = skb->data;
  93                         decaps = 1;
  94                         break;
  95                 }
  96
  97                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  98                         goto drop;
  99         } while (!err);
 100
 101         /* Allocate new secpath or COW existing one. */
 102         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 103                 struct sec_path *sp;
 104                 sp = secpath_dup(skb->sp);
 105                 if (!sp)
 106                         goto drop;
 107                 if (skb->sp)
 108                         secpath_put(skb->sp);
 109                 skb->sp = sp;
 110         }
 111
 112         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
 113                 goto drop;
 114
 115         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
 116         skb->sp->len += xfrm_nr;
 117         skb->ip_summed = CHECKSUM_NONE;
 118
 119         if (decaps) {
 120                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 121                         dst_release(skb->dst);
 122                         skb->dst = NULL;
 123                 }
 124                 netif_rx(skb);
 125                 return -1;
 126         } else {
 127                 return 1;
 128         }
 129
 130 drop_unlock:
 131         spin_unlock(&x->lock);
 132         xfrm_state_put(x);
 133 drop:
 134         while (--xfrm_nr >= 0)
 135                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
 136         kfree_skb(skb);
 137         return -1;
 138 }