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