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_IP6_PRE_ROUTING, skb, skb->dev, NULL,
  41                 ip6_rcv_finish);
  42         return -1;
  43 #else
  44         return 1;
  45 #endif
  46 }
  47
  48 int xfrm6_rcv(struct sk_buff *skb)
  49 {
  50         return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
  51                              0);
  52 }
  53
  54 EXPORT_SYMBOL(xfrm6_rcv);
  55
  56 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
  57                      xfrm_address_t *saddr, u8 proto)
  58 {
  59         struct xfrm_state *x = NULL;
  60         int wildcard = 0;
  61         xfrm_address_t *xany;
  62         struct xfrm_state *xfrm_vec_one = NULL;
  63         int nh = 0;
  64         int i = 0;
  65
  66         xany = (xfrm_address_t *)&in6addr_any;
  67
  68         for (i = 0; i < 3; i++) {
  69                 xfrm_address_t *dst, *src;
  70                 switch (i) {
  71                 case 0:
  72                         dst = daddr;
  73                         src = saddr;
  74                         break;
  75                 case 1:
  76                         /* lookup state with wild-card source address */
  77                         wildcard = 1;
  78                         dst = daddr;
  79                         src = xany;
  80                         break;
  81                 case 2:
  82                 default:
  83                         /* lookup state with wild-card addresses */
  84                         wildcard = 1; /* XXX */
  85                         dst = xany;
  86                         src = xany;
  87                         break;
  88                 }
  89
  90                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
  91                 if (!x)
  92                         continue;
  93
  94                 spin_lock(&x->lock);
  95
  96                 if (wildcard) {
  97                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
  98                                 spin_unlock(&x->lock);
  99                                 xfrm_state_put(x);
 100                                 x = NULL;
 101                                 continue;
 102                         }
 103                 }
 104
 105                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 106                         spin_unlock(&x->lock);
 107                         xfrm_state_put(x);
 108                         x = NULL;
 109                         continue;
 110                 }
 111                 if (xfrm_state_check_expire(x)) {
 112                         spin_unlock(&x->lock);
 113                         xfrm_state_put(x);
 114                         x = NULL;
 115                         continue;
 116                 }
 117
 118                 nh = x->type->input(x, skb);
 119                 if (nh <= 0) {
 120                         spin_unlock(&x->lock);
 121                         xfrm_state_put(x);
 122                         x = NULL;
 123                         continue;
 124                 }
 125
 126                 x->curlft.bytes += skb->len;
 127                 x->curlft.packets++;
 128
 129                 spin_unlock(&x->lock);
 130
 131                 xfrm_vec_one = x;
 132                 break;
 133         }
 134
 135         if (!xfrm_vec_one)
 136                 goto drop;
 137
 138         /* Allocate new secpath or COW existing one. */
 139         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 140                 struct sec_path *sp;
 141                 sp = secpath_dup(skb->sp);
 142                 if (!sp)
 143                         goto drop;
 144                 if (skb->sp)
 145                         secpath_put(skb->sp);
 146                 skb->sp = sp;
 147         }
 148
 149         if (1 + skb->sp->len > XFRM_MAX_DEPTH)
 150                 goto drop;
 151
 152         skb->sp->xvec[skb->sp->len] = xfrm_vec_one;
 153         skb->sp->len ++;
 154
 155         return 1;
 156 drop:
 157         if (xfrm_vec_one)
 158                 xfrm_state_put(xfrm_vec_one);
 159         return -1;
 160 }
 161
 162 EXPORT_SYMBOL(xfrm6_input_addr);