net/xfrm/xfrm_input.c

   1 /*
   2  * xfrm_input.c
   3  *
   4  * Changes:
   5  *      YOSHIFUJI Hideaki @USAGI
   6  *              Split up af-specific portion
   7  *
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/module.h>
  12 #include <linux/netdevice.h>
  13 #include <net/dst.h>
  14 #include <net/ip.h>
  15 #include <net/xfrm.h>
  16
  17 static struct kmem_cache *secpath_cachep __read_mostly;
  18
  19 void __secpath_destroy(struct sec_path *sp)
  20 {
  21         int i;
  22         for (i = 0; i < sp->len; i++)
  23                 xfrm_state_put(sp->xvec[i]);
  24         kmem_cache_free(secpath_cachep, sp);
  25 }
  26 EXPORT_SYMBOL(__secpath_destroy);
  27
  28 struct sec_path *secpath_dup(struct sec_path *src)
  29 {
  30         struct sec_path *sp;
  31
  32         sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
  33         if (!sp)
  34                 return NULL;
  35
  36         sp->len = 0;
  37         if (src) {
  38                 int i;
  39
  40                 memcpy(sp, src, sizeof(*sp));
  41                 for (i = 0; i < sp->len; i++)
  42                         xfrm_state_hold(sp->xvec[i]);
  43         }
  44         atomic_set(&sp->refcnt, 1);
  45         return sp;
  46 }
  47 EXPORT_SYMBOL(secpath_dup);
  48
  49 /* Fetch spi and seq from ipsec header */
  50
  51 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
  52 {
  53         int offset, offset_seq;
  54         int hlen;
  55
  56         switch (nexthdr) {
  57         case IPPROTO_AH:
  58                 hlen = sizeof(struct ip_auth_hdr);
  59                 offset = offsetof(struct ip_auth_hdr, spi);
  60                 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
  61                 break;
  62         case IPPROTO_ESP:
  63                 hlen = sizeof(struct ip_esp_hdr);
  64                 offset = offsetof(struct ip_esp_hdr, spi);
  65                 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
  66                 break;
  67         case IPPROTO_COMP:
  68                 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
  69                         return -EINVAL;
  70                 *spi = htonl(ntohs(*(__be16*)(skb_transport_header(skb) + 2)));
  71                 *seq = 0;
  72                 return 0;
  73         default:
  74                 return 1;
  75         }
  76
  77         if (!pskb_may_pull(skb, hlen))
  78                 return -EINVAL;
  79
  80         *spi = *(__be32*)(skb_transport_header(skb) + offset);
  81         *seq = *(__be32*)(skb_transport_header(skb) + offset_seq);
  82         return 0;
  83 }
  84
  85 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
  86 {
  87         struct xfrm_mode *inner_mode = x->inner_mode;
  88         int err;
  89
  90         err = x->outer_mode->afinfo->extract_input(x, skb);
  91         if (err)
  92                 return err;
  93
  94         if (x->sel.family == AF_UNSPEC) {
  95                 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
  96                 if (inner_mode == NULL)
  97                         return -EAFNOSUPPORT;
  98         }
  99
 100         skb->protocol = inner_mode->afinfo->eth_proto;
 101         return inner_mode->input2(x, skb);
 102 }
 103 EXPORT_SYMBOL(xfrm_prepare_input);
 104
 105 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 106 {
 107         struct net *net = dev_net(skb->dev);
 108         int err;
 109         __be32 seq;
 110         struct xfrm_state *x;
 111         xfrm_address_t *daddr;
 112         struct xfrm_mode *inner_mode;
 113         unsigned int family;
 114         int decaps = 0;
 115         int async = 0;
 116
 117         /* A negative encap_type indicates async resumption. */
 118         if (encap_type < 0) {
 119                 async = 1;
 120                 x = xfrm_input_state(skb);
 121                 seq = XFRM_SKB_CB(skb)->seq.input;
 122                 goto resume;
 123         }
 124
 125         /* Allocate new secpath or COW existing one. */
 126         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 127                 struct sec_path *sp;
 128
 129                 sp = secpath_dup(skb->sp);
 130                 if (!sp) {
 131                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 132                         goto drop;
 133                 }
 134                 if (skb->sp)
 135                         secpath_put(skb->sp);
 136                 skb->sp = sp;
 137         }
 138
 139         daddr = (xfrm_address_t *)(skb_network_header(skb) +
 140                                    XFRM_SPI_SKB_CB(skb)->daddroff);
 141         family = XFRM_SPI_SKB_CB(skb)->family;
 142
 143         seq = 0;
 144         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 145                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 146                 goto drop;
 147         }
 148
 149         do {
 150                 if (skb->sp->len == XFRM_MAX_DEPTH) {
 151                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 152                         goto drop;
 153                 }
 154
 155                 x = xfrm_state_lookup(net, daddr, spi, nexthdr, family);
 156                 if (x == NULL) {
 157                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
 158                         xfrm_audit_state_notfound(skb, family, spi, seq);
 159                         goto drop;
 160                 }
 161
 162                 skb->sp->xvec[skb->sp->len++] = x;
 163
 164                 spin_lock(&x->lock);
 165                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 166                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEINVALID);
 167                         goto drop_unlock;
 168                 }
 169
 170                 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 171                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
 172                         goto drop_unlock;
 173                 }
 174
 175                 if (x->props.replay_window && xfrm_replay_check(x, skb, seq)) {
 176                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 177                         goto drop_unlock;
 178                 }
 179
 180                 if (xfrm_state_check_expire(x)) {
 181                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
 182                         goto drop_unlock;
 183                 }
 184
 185                 spin_unlock(&x->lock);
 186
 187                 XFRM_SKB_CB(skb)->seq.input = seq;
 188
 189                 nexthdr = x->type->input(x, skb);
 190
 191                 if (nexthdr == -EINPROGRESS)
 192                         return 0;
 193
 194 resume:
 195                 spin_lock(&x->lock);
 196                 if (nexthdr <= 0) {
 197                         if (nexthdr == -EBADMSG) {
 198                                 xfrm_audit_state_icvfail(x, skb,
 199                                                          x->type->proto);
 200                                 x->stats.integrity_failed++;
 201                         }
 202                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 203                         goto drop_unlock;
 204                 }
 205
 206                 /* only the first xfrm gets the encap type */
 207                 encap_type = 0;
 208
 209                 if (x->props.replay_window)
 210                         xfrm_replay_advance(x, seq);
 211
 212                 x->curlft.bytes += skb->len;
 213                 x->curlft.packets++;
 214
 215                 spin_unlock(&x->lock);
 216
 217                 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
 218
 219                 inner_mode = x->inner_mode;
 220
 221                 if (x->sel.family == AF_UNSPEC) {
 222                         inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 223                         if (inner_mode == NULL)
 224                                 goto drop;
 225                 }
 226
 227                 if (inner_mode->input(x, skb)) {
 228                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 229                         goto drop;
 230                 }
 231
 232                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 233                         decaps = 1;
 234                         break;
 235                 }
 236
 237                 /*
 238                  * We need the inner address.  However, we only get here for
 239                  * transport mode so the outer address is identical.
 240                  */
 241                 daddr = &x->id.daddr;
 242                 family = x->outer_mode->afinfo->family;
 243
 244                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 245                 if (err < 0) {
 246                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 247                         goto drop;
 248                 }
 249         } while (!err);
 250
 251         nf_reset(skb);
 252
 253         if (decaps) {
 254                 skb_dst_drop(skb);
 255                 netif_rx(skb);
 256                 return 0;
 257         } else {
 258                 return x->inner_mode->afinfo->transport_finish(skb, async);
 259         }
 260
 261 drop_unlock:
 262         spin_unlock(&x->lock);
 263 drop:
 264         kfree_skb(skb);
 265         return 0;
 266 }
 267 EXPORT_SYMBOL(xfrm_input);
 268
 269 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 270 {
 271         return xfrm_input(skb, nexthdr, 0, -1);
 272 }
 273 EXPORT_SYMBOL(xfrm_input_resume);
 274
 275 void __init xfrm_input_init(void)
 276 {
 277         secpath_cachep = kmem_cache_create("secpath_cache",
 278                                            sizeof(struct sec_path),
 279                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 280                                            NULL);
 281 }