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 <net/dsfield.h>
  15 #include <net/inet_ecn.h>
  16 #include <net/ip.h>
  17 #include <net/ipv6.h>
  18 #include <net/xfrm.h>
  19
  20 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
  21 {
  22         struct ipv6hdr *outer_iph = skb->nh.ipv6h;
  23         struct ipv6hdr *inner_iph = skb->h.ipv6h;
  24
  25         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
  26                 IP6_ECN_set_ce(inner_iph);
  27 }
  28
  29 int xfrm6_rcv_spi(struct sk_buff **pskb, unsigned int *nhoffp, u32 spi)
  30 {
  31         struct sk_buff *skb = *pskb;
  32         int err;
  33         u32 seq;
  34         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
  35         struct xfrm_state *x;
  36         int xfrm_nr = 0;
  37         int decaps = 0;
  38         int nexthdr;
  39         unsigned int nhoff;
  40
  41         nhoff = *nhoffp;
  42         nexthdr = skb->nh.raw[nhoff];
  43
  44         seq = 0;
  45         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  46                 goto drop;
  47
  48         do {
  49                 struct ipv6hdr *iph = skb->nh.ipv6h;
  50
  51                 if (xfrm_nr == XFRM_MAX_DEPTH)
  52                         goto drop;
  53
  54                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  55                 if (x == NULL)
  56                         goto drop;
  57                 spin_lock(&x->lock);
  58                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  59                         goto drop_unlock;
  60
  61                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  62                         goto drop_unlock;
  63
  64                 if (xfrm_state_check_expire(x))
  65                         goto drop_unlock;
  66
  67                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
  68                 if (nexthdr <= 0)
  69                         goto drop_unlock;
  70
  71                 skb->nh.raw[nhoff] = nexthdr;
  72
  73                 if (x->props.replay_window)
  74                         xfrm_replay_advance(x, seq);
  75
  76                 x->curlft.bytes += skb->len;
  77                 x->curlft.packets++;
  78
  79                 spin_unlock(&x->lock);
  80
  81                 xfrm_vec[xfrm_nr++].xvec = x;
  82
  83                 if (x->props.mode) { /* XXX */
  84                         if (nexthdr != IPPROTO_IPV6)
  85                                 goto drop;
  86                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  87                                 goto drop;
  88                         if (skb_cloned(skb) &&
  89                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
  90                                 goto drop;
  91                         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
  92                                 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
  93                         if (!(x->props.flags & XFRM_STATE_NOECN))
  94                                 ipip6_ecn_decapsulate(skb);
  95                         skb->mac.raw = memmove(skb->data - skb->mac_len,
  96                                                skb->mac.raw, skb->mac_len);
  97                         skb->nh.raw = skb->data;
  98                         decaps = 1;
  99                         break;
 100                 }
 101
 102                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
 103                         goto drop;
 104         } while (!err);
 105
 106         /* Allocate new secpath or COW existing one. */
 107         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 108                 struct sec_path *sp;
 109                 sp = secpath_dup(skb->sp);
 110                 if (!sp)
 111                         goto drop;
 112                 if (skb->sp)
 113                         secpath_put(skb->sp);
 114                 skb->sp = sp;
 115         }
 116
 117         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
 118                 goto drop;
 119
 120         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
 121         skb->sp->len += xfrm_nr;
 122         skb->ip_summed = CHECKSUM_NONE;
 123
 124         if (decaps) {
 125                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 126                         dst_release(skb->dst);
 127                         skb->dst = NULL;
 128                 }
 129                 netif_rx(skb);
 130                 return -1;
 131         } else {
 132                 return 1;
 133         }
 134
 135 drop_unlock:
 136         spin_unlock(&x->lock);
 137         xfrm_state_put(x);
 138 drop:
 139         while (--xfrm_nr >= 0)
 140                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
 141         kfree_skb(skb);
 142         return -1;
 143 }
 144
 145 EXPORT_SYMBOL(xfrm6_rcv_spi);
 146
 147 int xfrm6_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
 148 {
 149         return xfrm6_rcv_spi(pskb, nhoffp, 0);
 150 }