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         int err;
  27         __be32 seq;
  28         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
  29         struct xfrm_state *x;
  30         int xfrm_nr = 0;
  31         int decaps = 0;
  32         unsigned int nhoff;
  33
  34         nhoff = IP6CB(skb)->nhoff;
  35
  36         seq = 0;
  37         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  38                 goto drop;
  39
  40         do {
  41                 struct ipv6hdr *iph = ipv6_hdr(skb);
  42
  43                 if (xfrm_nr == XFRM_MAX_DEPTH)
  44                         goto drop;
  45
  46                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
  47                                       nexthdr, AF_INET6);
  48                 if (x == NULL)
  49                         goto drop;
  50                 spin_lock(&x->lock);
  51                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  52                         goto drop_unlock;
  53
  54                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  55                         goto drop_unlock;
  56
  57                 if (xfrm_state_check_expire(x))
  58                         goto drop_unlock;
  59
  60                 nexthdr = x->type->input(x, skb);
  61                 if (nexthdr <= 0)
  62                         goto drop_unlock;
  63
  64                 skb_network_header(skb)[nhoff] = nexthdr;
  65
  66                 if (x->props.replay_window)
  67                         xfrm_replay_advance(x, seq);
  68
  69                 x->curlft.bytes += skb->len;
  70                 x->curlft.packets++;
  71
  72                 spin_unlock(&x->lock);
  73
  74                 xfrm_vec[xfrm_nr++] = x;
  75
  76                 if (x->inner_mode->input(x, skb))
  77                         goto drop;
  78
  79                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
  80                         decaps = 1;
  81                         break;
  82                 }
  83
  84                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  85                         goto drop;
  86         } while (!err);
  87
  88         /* Allocate new secpath or COW existing one. */
  89         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  90                 struct sec_path *sp;
  91                 sp = secpath_dup(skb->sp);
  92                 if (!sp)
  93                         goto drop;
  94                 if (skb->sp)
  95                         secpath_put(skb->sp);
  96                 skb->sp = sp;
  97         }
  98
  99         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
 100                 goto drop;
 101
 102         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
 103                xfrm_nr * sizeof(xfrm_vec[0]));
 104         skb->sp->len += xfrm_nr;
 105
 106         nf_reset(skb);
 107
 108         if (decaps) {
 109                 dst_release(skb->dst);
 110                 skb->dst = NULL;
 111                 netif_rx(skb);
 112                 return -1;
 113         } else {
 114 #ifdef CONFIG_NETFILTER
 115                 ipv6_hdr(skb)->payload_len = htons(skb->len);
 116                 __skb_push(skb, skb->data - skb_network_header(skb));
 117
 118                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
 119                         ip6_rcv_finish);
 120                 return -1;
 121 #else
 122                 return 1;
 123 #endif
 124         }
 125
 126 drop_unlock:
 127         spin_unlock(&x->lock);
 128         xfrm_state_put(x);
 129 drop:
 130         while (--xfrm_nr >= 0)
 131                 xfrm_state_put(xfrm_vec[xfrm_nr]);
 132         kfree_skb(skb);
 133         return -1;
 134 }
 135
 136 EXPORT_SYMBOL(xfrm6_rcv_spi);
 137
 138 int xfrm6_rcv(struct sk_buff *skb)
 139 {
 140         return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
 141                              0);
 142 }
 143
 144 EXPORT_SYMBOL(xfrm6_rcv);
 145
 146 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
 147                      xfrm_address_t *saddr, u8 proto)
 148 {
 149         struct xfrm_state *x = NULL;
 150         int wildcard = 0;
 151         xfrm_address_t *xany;
 152         struct xfrm_state *xfrm_vec_one = NULL;
 153         int nh = 0;
 154         int i = 0;
 155
 156         xany = (xfrm_address_t *)&in6addr_any;
 157
 158         for (i = 0; i < 3; i++) {
 159                 xfrm_address_t *dst, *src;
 160                 switch (i) {
 161                 case 0:
 162                         dst = daddr;
 163                         src = saddr;
 164                         break;
 165                 case 1:
 166                         /* lookup state with wild-card source address */
 167                         wildcard = 1;
 168                         dst = daddr;
 169                         src = xany;
 170                         break;
 171                 case 2:
 172                 default:
 173                         /* lookup state with wild-card addresses */
 174                         wildcard = 1; /* XXX */
 175                         dst = xany;
 176                         src = xany;
 177                         break;
 178                 }
 179
 180                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
 181                 if (!x)
 182                         continue;
 183
 184                 spin_lock(&x->lock);
 185
 186                 if (wildcard) {
 187                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
 188                                 spin_unlock(&x->lock);
 189                                 xfrm_state_put(x);
 190                                 x = NULL;
 191                                 continue;
 192                         }
 193                 }
 194
 195                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 196                         spin_unlock(&x->lock);
 197                         xfrm_state_put(x);
 198                         x = NULL;
 199                         continue;
 200                 }
 201                 if (xfrm_state_check_expire(x)) {
 202                         spin_unlock(&x->lock);
 203                         xfrm_state_put(x);
 204                         x = NULL;
 205                         continue;
 206                 }
 207
 208                 nh = x->type->input(x, skb);
 209                 if (nh <= 0) {
 210                         spin_unlock(&x->lock);
 211                         xfrm_state_put(x);
 212                         x = NULL;
 213                         continue;
 214                 }
 215
 216                 x->curlft.bytes += skb->len;
 217                 x->curlft.packets++;
 218
 219                 spin_unlock(&x->lock);
 220
 221                 xfrm_vec_one = x;
 222                 break;
 223         }
 224
 225         if (!xfrm_vec_one)
 226                 goto drop;
 227
 228         /* Allocate new secpath or COW existing one. */
 229         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 230                 struct sec_path *sp;
 231                 sp = secpath_dup(skb->sp);
 232                 if (!sp)
 233                         goto drop;
 234                 if (skb->sp)
 235                         secpath_put(skb->sp);
 236                 skb->sp = sp;
 237         }
 238
 239         if (1 + skb->sp->len > XFRM_MAX_DEPTH)
 240                 goto drop;
 241
 242         skb->sp->xvec[skb->sp->len] = xfrm_vec_one;
 243         skb->sp->len ++;
 244
 245         return 1;
 246 drop:
 247         if (xfrm_vec_one)
 248                 xfrm_state_put(xfrm_vec_one);
 249         return -1;
 250 }
 251
 252 EXPORT_SYMBOL(xfrm6_input_addr);