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_extract_input(struct xfrm_state *x, struct sk_buff *skb)
  20 {
  21         return xfrm6_extract_header(skb);
  22 }
  23
  24 int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
  25 {
  26         XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
  27         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
  28         return xfrm_input(skb, nexthdr, spi, 0);
  29 }
  30 EXPORT_SYMBOL(xfrm6_rcv_spi);
  31
  32 int xfrm6_transport_finish(struct sk_buff *skb, int async)
  33 {
  34         skb_network_header(skb)[IP6CB(skb)->nhoff] =
  35                 XFRM_MODE_SKB_CB(skb)->protocol;
  36
  37 #ifndef CONFIG_NETFILTER
  38         if (!async)
  39                 return 1;
  40 #endif
  41
  42         ipv6_hdr(skb)->payload_len = htons(skb->len);
  43         __skb_push(skb, skb->data - skb_network_header(skb));
  44
  45         NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
  46                 ip6_rcv_finish);
  47         return -1;
  48 }
  49
  50 int xfrm6_rcv(struct sk_buff *skb)
  51 {
  52         return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
  53                              0);
  54 }
  55
  56 EXPORT_SYMBOL(xfrm6_rcv);
  57
  58 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
  59                      xfrm_address_t *saddr, u8 proto)
  60 {
  61         struct xfrm_state *x = NULL;
  62         int i = 0;
  63
  64         /* Allocate new secpath or COW existing one. */
  65         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  66                 struct sec_path *sp;
  67
  68                 sp = secpath_dup(skb->sp);
  69                 if (!sp) {
  70                         XFRM_INC_STATS(LINUX_MIB_XFRMINERROR);
  71                         goto drop;
  72                 }
  73                 if (skb->sp)
  74                         secpath_put(skb->sp);
  75                 skb->sp = sp;
  76         }
  77
  78         if (1 + skb->sp->len == XFRM_MAX_DEPTH) {
  79                 XFRM_INC_STATS(LINUX_MIB_XFRMINBUFFERERROR);
  80                 goto drop;
  81         }
  82
  83         for (i = 0; i < 3; i++) {
  84                 xfrm_address_t *dst, *src;
  85
  86                 switch (i) {
  87                 case 0:
  88                         dst = daddr;
  89                         src = saddr;
  90                         break;
  91                 case 1:
  92                         /* lookup state with wild-card source address */
  93                         dst = daddr;
  94                         src = (xfrm_address_t *)&in6addr_any;
  95                         break;
  96                 default:
  97                         /* lookup state with wild-card addresses */
  98                         dst = (xfrm_address_t *)&in6addr_any;
  99                         src = (xfrm_address_t *)&in6addr_any;
 100                         break;
 101                 }
 102
 103                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
 104                 if (!x)
 105                         continue;
 106
 107                 spin_lock(&x->lock);
 108
 109                 if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
 110                     likely(x->km.state == XFRM_STATE_VALID) &&
 111                     !xfrm_state_check_expire(x)) {
 112                         spin_unlock(&x->lock);
 113                         if (x->type->input(x, skb) > 0) {
 114                                 /* found a valid state */
 115                                 break;
 116                         }
 117                 } else
 118                         spin_unlock(&x->lock);
 119
 120                 xfrm_state_put(x);
 121                 x = NULL;
 122         }
 123
 124         if (!x) {
 125                 XFRM_INC_STATS(LINUX_MIB_XFRMINNOSTATES);
 126                 xfrm_audit_state_notfound_simple(skb, AF_INET6);
 127                 goto drop;
 128         }
 129
 130         skb->sp->xvec[skb->sp->len++] = x;
 131
 132         spin_lock(&x->lock);
 133
 134         x->curlft.bytes += skb->len;
 135         x->curlft.packets++;
 136
 137         spin_unlock(&x->lock);
 138
 139         return 1;
 140
 141 drop:
 142         return -1;
 143 }
 144
 145 EXPORT_SYMBOL(xfrm6_input_addr);