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 wildcard = 0;
  63         xfrm_address_t *xany;
  64         int nh = 0;
  65         int i = 0;
  66
  67         /* Allocate new secpath or COW existing one. */
  68         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  69                 struct sec_path *sp;
  70
  71                 sp = secpath_dup(skb->sp);
  72                 if (!sp) {
  73                         XFRM_INC_STATS(LINUX_MIB_XFRMINERROR);
  74                         goto drop;
  75                 }
  76                 if (skb->sp)
  77                         secpath_put(skb->sp);
  78                 skb->sp = sp;
  79         }
  80
  81         if (1 + skb->sp->len == XFRM_MAX_DEPTH) {
  82                 XFRM_INC_STATS(LINUX_MIB_XFRMINBUFFERERROR);
  83                 goto drop;
  84         }
  85
  86         xany = (xfrm_address_t *)&in6addr_any;
  87
  88         for (i = 0; i < 3; i++) {
  89                 xfrm_address_t *dst, *src;
  90                 switch (i) {
  91                 case 0:
  92                         dst = daddr;
  93                         src = saddr;
  94                         break;
  95                 case 1:
  96                         /* lookup state with wild-card source address */
  97                         wildcard = 1;
  98                         dst = daddr;
  99                         src = xany;
 100                         break;
 101                 case 2:
 102                 default:
 103                         /* lookup state with wild-card addresses */
 104                         wildcard = 1; /* XXX */
 105                         dst = xany;
 106                         src = xany;
 107                         break;
 108                 }
 109
 110                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
 111                 if (!x)
 112                         continue;
 113
 114                 spin_lock(&x->lock);
 115
 116                 if (wildcard) {
 117                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
 118                                 spin_unlock(&x->lock);
 119                                 xfrm_state_put(x);
 120                                 x = NULL;
 121                                 continue;
 122                         }
 123                 }
 124
 125                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 126                         spin_unlock(&x->lock);
 127                         xfrm_state_put(x);
 128                         x = NULL;
 129                         continue;
 130                 }
 131                 if (xfrm_state_check_expire(x)) {
 132                         spin_unlock(&x->lock);
 133                         xfrm_state_put(x);
 134                         x = NULL;
 135                         continue;
 136                 }
 137
 138                 spin_unlock(&x->lock);
 139
 140                 nh = x->type->input(x, skb);
 141                 if (nh <= 0) {
 142                         xfrm_state_put(x);
 143                         x = NULL;
 144                         continue;
 145                 }
 146
 147                 /* Found a state */
 148                 break;
 149         }
 150
 151         if (!x) {
 152                 XFRM_INC_STATS(LINUX_MIB_XFRMINNOSTATES);
 153                 xfrm_audit_state_notfound_simple(skb, AF_INET6);
 154                 goto drop;
 155         }
 156
 157         skb->sp->xvec[skb->sp->len++] = x;
 158
 159         spin_lock(&x->lock);
 160
 161         x->curlft.bytes += skb->len;
 162         x->curlft.packets++;
 163
 164         spin_unlock(&x->lock);
 165
 166         return 1;
 167
 168 drop:
 169         return -1;
 170 }
 171
 172 EXPORT_SYMBOL(xfrm6_input_addr);