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->nh.raw[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 = skb->nh.ipv6h;
  39
  40                 if (xfrm_nr == XFRM_MAX_DEPTH)
  41                         goto drop;
  42
  43                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
  44                 if (x == NULL)
  45                         goto drop;
  46                 spin_lock(&x->lock);
  47                 if (unlikely(x->km.state != XFRM_STATE_VALID))
  48                         goto drop_unlock;
  49
  50                 if (x->props.replay_window && xfrm_replay_check(x, seq))
  51                         goto drop_unlock;
  52
  53                 if (xfrm_state_check_expire(x))
  54                         goto drop_unlock;
  55
  56                 nexthdr = x->type->input(x, skb);
  57                 if (nexthdr <= 0)
  58                         goto drop_unlock;
  59
  60                 skb->nh.raw[nhoff] = nexthdr;
  61
  62                 if (x->props.replay_window)
  63                         xfrm_replay_advance(x, seq);
  64
  65                 x->curlft.bytes += skb->len;
  66                 x->curlft.packets++;
  67
  68                 spin_unlock(&x->lock);
  69
  70                 xfrm_vec[xfrm_nr++] = x;
  71
  72                 if (x->mode->input(x, skb))
  73                         goto drop;
  74
  75                 if (x->props.mode == XFRM_MODE_TUNNEL) { /* XXX */
  76                         decaps = 1;
  77                         break;
  78                 }
  79
  80                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
  81                         goto drop;
  82         } while (!err);
  83
  84         /* Allocate new secpath or COW existing one. */
  85         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
  86                 struct sec_path *sp;
  87                 sp = secpath_dup(skb->sp);
  88                 if (!sp)
  89                         goto drop;
  90                 if (skb->sp)
  91                         secpath_put(skb->sp);
  92                 skb->sp = sp;
  93         }
  94
  95         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
  96                 goto drop;
  97
  98         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
  99                xfrm_nr * sizeof(xfrm_vec[0]));
 100         skb->sp->len += xfrm_nr;
 101         skb->ip_summed = CHECKSUM_NONE;
 102
 103         nf_reset(skb);
 104
 105         if (decaps) {
 106                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
 107                         dst_release(skb->dst);
 108                         skb->dst = NULL;
 109                 }
 110                 netif_rx(skb);
 111                 return -1;
 112         } else {
 113 #ifdef CONFIG_NETFILTER
 114                 skb->nh.ipv6h->payload_len = htons(skb->len);
 115                 __skb_push(skb, skb->data - skb->nh.raw);
 116
 117                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
 118                         ip6_rcv_finish);
 119                 return -1;
 120 #else
 121                 return 1;
 122 #endif
 123         }
 124
 125 drop_unlock:
 126         spin_unlock(&x->lock);
 127         xfrm_state_put(x);
 128 drop:
 129         while (--xfrm_nr >= 0)
 130                 xfrm_state_put(xfrm_vec[xfrm_nr]);
 131         kfree_skb(skb);
 132         return -1;
 133 }
 134
 135 EXPORT_SYMBOL(xfrm6_rcv_spi);
 136
 137 int xfrm6_rcv(struct sk_buff **pskb)
 138 {
 139         return xfrm6_rcv_spi(*pskb, 0);
 140 }
 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         struct in6_addr any;
 148         xfrm_address_t *xany;
 149         struct xfrm_state *xfrm_vec_one = NULL;
 150         int nh = 0;
 151         int i = 0;
 152
 153         ipv6_addr_set(&any, 0, 0, 0, 0);
 154         xany = (xfrm_address_t *)&any;
 155
 156         for (i = 0; i < 3; i++) {
 157                 xfrm_address_t *dst, *src;
 158                 switch (i) {
 159                 case 0:
 160                         dst = daddr;
 161                         src = saddr;
 162                         break;
 163                 case 1:
 164                         /* lookup state with wild-card source address */
 165                         wildcard = 1;
 166                         dst = daddr;
 167                         src = xany;
 168                         break;
 169                 case 2:
 170                 default:
 171                         /* lookup state with wild-card addresses */
 172                         wildcard = 1; /* XXX */
 173                         dst = xany;
 174                         src = xany;
 175                         break;
 176                 }
 177
 178                 x = xfrm_state_lookup_byaddr(dst, src, proto, AF_INET6);
 179                 if (!x)
 180                         continue;
 181
 182                 spin_lock(&x->lock);
 183
 184                 if (wildcard) {
 185                         if ((x->props.flags & XFRM_STATE_WILDRECV) == 0) {
 186                                 spin_unlock(&x->lock);
 187                                 xfrm_state_put(x);
 188                                 x = NULL;
 189                                 continue;
 190                         }
 191                 }
 192
 193                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 194                         spin_unlock(&x->lock);
 195                         xfrm_state_put(x);
 196                         x = NULL;
 197                         continue;
 198                 }
 199                 if (xfrm_state_check_expire(x)) {
 200                         spin_unlock(&x->lock);
 201                         xfrm_state_put(x);
 202                         x = NULL;
 203                         continue;
 204                 }
 205
 206                 nh = x->type->input(x, skb);
 207                 if (nh <= 0) {
 208                         spin_unlock(&x->lock);
 209                         xfrm_state_put(x);
 210                         x = NULL;
 211                         continue;
 212                 }
 213
 214                 x->curlft.bytes += skb->len;
 215                 x->curlft.packets++;
 216
 217                 spin_unlock(&x->lock);
 218
 219                 xfrm_vec_one = x;
 220                 break;
 221         }
 222
 223         if (!xfrm_vec_one)
 224                 goto drop;
 225
 226         /* Allocate new secpath or COW existing one. */
 227         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 228                 struct sec_path *sp;
 229                 sp = secpath_dup(skb->sp);
 230                 if (!sp)
 231                         goto drop;
 232                 if (skb->sp)
 233                         secpath_put(skb->sp);
 234                 skb->sp = sp;
 235         }
 236
 237         if (1 + skb->sp->len > XFRM_MAX_DEPTH)
 238                 goto drop;
 239
 240         skb->sp->xvec[skb->sp->len] = xfrm_vec_one;
 241         skb->sp->len ++;
 242
 243         return 1;
 244 drop:
 245         if (xfrm_vec_one)
 246                 xfrm_state_put(xfrm_vec_one);
 247         return -1;
 248 }