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_rcv_spi(struct sk_buff *skb, __be32 spi)
  20 {
  21         int err;
  22         __be32 seq;
  23         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
  24         struct xfrm_state *x;
  25         int xfrm_nr = 0;
  26         int decaps = 0;
  27         int nexthdr;
  28         unsigned int nhoff;
  29
  30         nhoff = IP6CB(skb)->nhoff;
  31         nexthdr = skb_network_header(skb)[nhoff];
  32
  33         seq = 0;
  34         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
  35                 goto drop;
  36
  37         do {
  38                 struct ipv6hdr *iph = ipv6_hdr(skb);
  39
  40                 if (xfrm_nr == XFRM_MAX_DEPTH)
  41                         goto drop;
  42
  43                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
  44                                 nexthdr != IPPROTO_IPIP ? nexthdr : IPPROTO_IPV6, AF_INET6);
  45                 if (x == NULL)
  46                         goto drop;
  47                 spin_lock(&x->lock);
  48                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  49                         goto drop_unlock;
  50
  51                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  52                         goto drop_unlock;
  53
  54                 if (xfrm_state_check_expire(x))
  55                         goto drop_unlock;
  56
  57                 nexthdr = x->type->input(x, skb);
  58                 if (nexthdr <= 0)
  59                         goto drop_unlock;
  60
  61                 skb_network_header(skb)[nhoff] = nexthdr;
  62
  63                 if (x->props.replay_window)
  64                         xfrm_replay_advance(x, seq);
  65
  66                 x->curlft.bytes += skb->len;
  67                 x->curlft.packets++;
  68
  69                 spin_unlock(&x->lock);
  70
  71                 xfrm_vec[xfrm_nr++] = x;
  72
  73                 if (x->mode->input(x, skb))
  74                         goto drop;
  75
  76                 if (x->props.mode == XFRM_MODE_TUNNEL) { /* XXX */
  77                         decaps = 1;
  78                         break;
  79                 }
  80
  81                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  82                         goto drop;
  83         } while (!err);
  84
  85         /* Allocate new secpath or COW existing one. */
  86         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  87                 struct sec_path *sp;
  88                 sp = secpath_dup(skb->sp);
  89                 if (!sp)
  90                         goto drop;
  91                 if (skb->sp)
  92                         secpath_put(skb->sp);
  93                 skb->sp = sp;
  94         }
  95
  96         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
  97                 goto drop;
  98
  99         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
 100                xfrm_nr * sizeof(xfrm_vec[0]));
 101         skb->sp->len += xfrm_nr;
 102         skb->ip_summed = CHECKSUM_NONE;
 103
 104         nf_reset(skb);
 105
 106         if (decaps) {
 107                 dst_release(skb->dst);
 108                 skb->dst = NULL;
 109                 netif_rx(skb);
 110                 return -1;
 111         } else {
 112 #ifdef CONFIG_NETFILTER
 113                 ipv6_hdr(skb)->payload_len = htons(skb->len);
 114                 __skb_push(skb, skb->data - skb_network_header(skb));
 115
 116                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
 117                         ip6_rcv_finish);
 118                 return -1;
 119 #else
 120                 return 1;
 121 #endif
 122         }
 123
 124 drop_unlock:
 125         spin_unlock(&x->lock);
 126         xfrm_state_put(x);
 127 drop:
 128         while (--xfrm_nr >= 0)
 129                 xfrm_state_put(xfrm_vec[xfrm_nr]);
 130         kfree_skb(skb);
 131         return -1;
 132 }
 133
 134 EXPORT_SYMBOL(xfrm6_rcv_spi);
 135
 136 int xfrm6_rcv(struct sk_buff **pskb)
 137 {
 138         return xfrm6_rcv_spi(*pskb, 0);
 139 }
 140
 141 EXPORT_SYMBOL(xfrm6_rcv);
 142
 143 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
 144                      xfrm_address_t *saddr, u8 proto)
 145 {
 146         struct xfrm_state *x = NULL;
 147         int wildcard = 0;
 148         xfrm_address_t *xany;
 149         struct xfrm_state *xfrm_vec_one = NULL;
 150         int nh = 0;
 151         int i = 0;
 152
 153         xany = (xfrm_address_t *)&in6addr_any;
 154
 155         for (i = 0; i < 3; i++) {
 156                 xfrm_address_t *dst, *src;
 157                 switch (i) {
 158                 case 0:
 159                         dst = daddr;
 160                         src = saddr;
 161                         break;
 162                 case 1:
 163                         /* lookup state with wild-card source address */
 164                         wildcard = 1;
 165                         dst = daddr;
 166                         src = xany;
 167                         break;
 168                 case 2:
 169                 default:
 170                         /* lookup state with wild-card addresses */
 171                         wildcard = 1; /* XXX */
 172                         dst = xany;
 173                         src = xany;
 174                         break;
 175                 }
 176
 177                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
 178                 if (!x)
 179                         continue;
 180
 181                 spin_lock(&x->lock);
 182
 183                 if (wildcard) {
 184                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
 185                                 spin_unlock(&x->lock);
 186                                 xfrm_state_put(x);
 187                                 x = NULL;
 188                                 continue;
 189                         }
 190                 }
 191
 192                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 193                         spin_unlock(&x->lock);
 194                         xfrm_state_put(x);
 195                         x = NULL;
 196                         continue;
 197                 }
 198                 if (xfrm_state_check_expire(x)) {
 199                         spin_unlock(&x->lock);
 200                         xfrm_state_put(x);
 201                         x = NULL;
 202                         continue;
 203                 }
 204
 205                 nh = x->type->input(x, skb);
 206                 if (nh <= 0) {
 207                         spin_unlock(&x->lock);
 208                         xfrm_state_put(x);
 209                         x = NULL;
 210                         continue;
 211                 }
 212
 213                 x->curlft.bytes += skb->len;
 214                 x->curlft.packets++;
 215
 216                 spin_unlock(&x->lock);
 217
 218                 xfrm_vec_one = x;
 219                 break;
 220         }
 221
 222         if (!xfrm_vec_one)
 223                 goto drop;
 224
 225         /* Allocate new secpath or COW existing one. */
 226         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 227                 struct sec_path *sp;
 228                 sp = secpath_dup(skb->sp);
 229                 if (!sp)
 230                         goto drop;
 231                 if (skb->sp)
 232                         secpath_put(skb->sp);
 233                 skb->sp = sp;
 234         }
 235
 236         if (1 + skb->sp->len > XFRM_MAX_DEPTH)
 237                 goto drop;
 238
 239         skb->sp->xvec[skb->sp->len] = xfrm_vec_one;
 240         skb->sp->len ++;
 241
 242         return 1;
 243 drop:
 244         if (xfrm_vec_one)
 245                 xfrm_state_put(xfrm_vec_one);
 246         return -1;
 247 }
 248
 249 EXPORT_SYMBOL(xfrm6_input_addr);