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)->daddroff = offsetof(struct ipv6hdr, daddr);
  27         return xfrm_input(skb, nexthdr, spi, 0);
  28 }
  29 EXPORT_SYMBOL(xfrm6_rcv_spi);
  30
  31 int xfrm6_transport_finish(struct sk_buff *skb, int async)
  32 {
  33         skb_network_header(skb)[IP6CB(skb)->nhoff] =
  34                 XFRM_MODE_SKB_CB(skb)->protocol;
  35
  36 #ifdef CONFIG_NETFILTER
  37         ipv6_hdr(skb)->payload_len = htons(skb->len);
  38         __skb_push(skb, skb->data - skb_network_header(skb));
  39
  40         NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
  41                 ip6_rcv_finish);
  42         return -1;
  43 #else
  44         if (async)
  45                 return ip6_rcv_finish(skb);
  46
  47         return 1;
  48 #endif
  49 }
  50
  51 int xfrm6_rcv(struct sk_buff *skb)
  52 {
  53         return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
  54                              0);
  55 }
  56
  57 EXPORT_SYMBOL(xfrm6_rcv);
  58
  59 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
  60                      xfrm_address_t *saddr, u8 proto)
  61 {
  62         struct xfrm_state *x = NULL;
  63         int wildcard = 0;
  64         xfrm_address_t *xany;
  65         struct xfrm_state *xfrm_vec_one = NULL;
  66         int nh = 0;
  67         int i = 0;
  68
  69         xany = (xfrm_address_t *)&in6addr_any;
  70
  71         for (i = 0; i < 3; i++) {
  72                 xfrm_address_t *dst, *src;
  73                 switch (i) {
  74                 case 0:
  75                         dst = daddr;
  76                         src = saddr;
  77                         break;
  78                 case 1:
  79                         /* lookup state with wild-card source address */
  80                         wildcard = 1;
  81                         dst = daddr;
  82                         src = xany;
  83                         break;
  84                 case 2:
  85                 default:
  86                         /* lookup state with wild-card addresses */
  87                         wildcard = 1; /* XXX */
  88                         dst = xany;
  89                         src = xany;
  90                         break;
  91                 }
  92
  93                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
  94                 if (!x)
  95                         continue;
  96
  97                 spin_lock(&x->lock);
  98
  99                 if (wildcard) {
 100                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
 101                                 spin_unlock(&x->lock);
 102                                 xfrm_state_put(x);
 103                                 x = NULL;
 104                                 continue;
 105                         }
 106                 }
 107
 108                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 109                         spin_unlock(&x->lock);
 110                         xfrm_state_put(x);
 111                         x = NULL;
 112                         continue;
 113                 }
 114                 if (xfrm_state_check_expire(x)) {
 115                         spin_unlock(&x->lock);
 116                         xfrm_state_put(x);
 117                         x = NULL;
 118                         continue;
 119                 }
 120
 121                 nh = x->type->input(x, skb);
 122                 if (nh <= 0) {
 123                         spin_unlock(&x->lock);
 124                         xfrm_state_put(x);
 125                         x = NULL;
 126                         continue;
 127                 }
 128
 129                 x->curlft.bytes += skb->len;
 130                 x->curlft.packets++;
 131
 132                 spin_unlock(&x->lock);
 133
 134                 xfrm_vec_one = x;
 135                 break;
 136         }
 137
 138         if (!xfrm_vec_one)
 139                 goto drop;
 140
 141         /* Allocate new secpath or COW existing one. */
 142         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 143                 struct sec_path *sp;
 144                 sp = secpath_dup(skb->sp);
 145                 if (!sp)
 146                         goto drop;
 147                 if (skb->sp)
 148                         secpath_put(skb->sp);
 149                 skb->sp = sp;
 150         }
 151
 152         if (1 + skb->sp->len > XFRM_MAX_DEPTH)
 153                 goto drop;
 154
 155         skb->sp->xvec[skb->sp->len] = xfrm_vec_one;
 156         skb->sp->len ++;
 157
 158         return 1;
 159 drop:
 160         if (xfrm_vec_one)
 161                 xfrm_state_put(xfrm_vec_one);
 162         return -1;
 163 }
 164
 165 EXPORT_SYMBOL(xfrm6_input_addr);