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         int err;
  88
  89         err = x->outer_mode->afinfo->extract_input(x, skb);
  90         if (err)
  91                 return err;
  92
  93         skb->protocol = x->inner_mode->afinfo->eth_proto;
  94         return x->inner_mode->input2(x, skb);
  95 }
  96 EXPORT_SYMBOL(xfrm_prepare_input);
  97
  98 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
  99 {
 100         int err;
 101         __be32 seq;
 102         struct xfrm_state *x;
 103         xfrm_address_t *daddr;
 104         unsigned int family;
 105         int decaps = 0;
 106         int async = 0;
 107
 108         /* A negative encap_type indicates async resumption. */
 109         if (encap_type < 0) {
 110                 async = 1;
 111                 x = xfrm_input_state(skb);
 112                 seq = XFRM_SKB_CB(skb)->seq;
 113                 goto resume;
 114         }
 115
 116         /* Allocate new secpath or COW existing one. */
 117         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 118                 struct sec_path *sp;
 119
 120                 sp = secpath_dup(skb->sp);
 121                 if (!sp) {
 122                         XFRM_INC_STATS(LINUX_MIB_XFRMINERROR);
 123                         goto drop;
 124                 }
 125                 if (skb->sp)
 126                         secpath_put(skb->sp);
 127                 skb->sp = sp;
 128         }
 129
 130         daddr = (xfrm_address_t *)(skb_network_header(skb) +
 131                                    XFRM_SPI_SKB_CB(skb)->daddroff);
 132         family = XFRM_SPI_SKB_CB(skb)->family;
 133
 134         seq = 0;
 135         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 136                 XFRM_INC_STATS(LINUX_MIB_XFRMINHDRERROR);
 137                 goto drop;
 138         }
 139
 140         do {
 141                 if (skb->sp->len == XFRM_MAX_DEPTH) {
 142                         XFRM_INC_STATS(LINUX_MIB_XFRMINBUFFERERROR);
 143                         goto drop;
 144                 }
 145
 146                 x = xfrm_state_lookup(daddr, spi, nexthdr, family);
 147                 if (x == NULL) {
 148                         XFRM_INC_STATS(LINUX_MIB_XFRMINNOSTATES);
 149                         xfrm_audit_state_notfound(skb, family, spi, seq);
 150                         goto drop;
 151                 }
 152
 153                 skb->sp->xvec[skb->sp->len++] = x;
 154
 155                 spin_lock(&x->lock);
 156                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 157                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEINVALID);
 158                         goto drop_unlock;
 159                 }
 160
 161                 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 162                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEMISMATCH);
 163                         goto drop_unlock;
 164                 }
 165
 166                 if (x->props.replay_window && xfrm_replay_check(x, skb, seq)) {
 167                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATESEQERROR);
 168                         goto drop_unlock;
 169                 }
 170
 171                 if (xfrm_state_check_expire(x)) {
 172                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEEXPIRED);
 173                         goto drop_unlock;
 174                 }
 175
 176                 spin_unlock(&x->lock);
 177
 178                 XFRM_SKB_CB(skb)->seq = seq;
 179
 180                 nexthdr = x->type->input(x, skb);
 181
 182                 if (nexthdr == -EINPROGRESS)
 183                         return 0;
 184
 185 resume:
 186                 spin_lock(&x->lock);
 187                 if (nexthdr <= 0) {
 188                         if (nexthdr == -EBADMSG) {
 189                                 xfrm_audit_state_icvfail(x, skb,
 190                                                          x->type->proto);
 191                                 x->stats.integrity_failed++;
 192                         }
 193                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEPROTOERROR);
 194                         goto drop_unlock;
 195                 }
 196
 197                 /* only the first xfrm gets the encap type */
 198                 encap_type = 0;
 199
 200                 if (x->props.replay_window)
 201                         xfrm_replay_advance(x, seq);
 202
 203                 x->curlft.bytes += skb->len;
 204                 x->curlft.packets++;
 205
 206                 spin_unlock(&x->lock);
 207
 208                 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
 209
 210                 if (x->inner_mode->input(x, skb)) {
 211                         XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEMODEERROR);
 212                         goto drop;
 213                 }
 214
 215                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 216                         decaps = 1;
 217                         break;
 218                 }
 219
 220                 /*
 221                  * We need the inner address.  However, we only get here for
 222                  * transport mode so the outer address is identical.
 223                  */
 224                 daddr = &x->id.daddr;
 225                 family = x->outer_mode->afinfo->family;
 226
 227                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 228                 if (err < 0) {
 229                         XFRM_INC_STATS(LINUX_MIB_XFRMINHDRERROR);
 230                         goto drop;
 231                 }
 232         } while (!err);
 233
 234         nf_reset(skb);
 235
 236         if (decaps) {
 237                 dst_release(skb->dst);
 238                 skb->dst = NULL;
 239                 netif_rx(skb);
 240                 return 0;
 241         } else {
 242                 return x->inner_mode->afinfo->transport_finish(skb, async);
 243         }
 244
 245 drop_unlock:
 246         spin_unlock(&x->lock);
 247 drop:
 248         kfree_skb(skb);
 249         return 0;
 250 }
 251 EXPORT_SYMBOL(xfrm_input);
 252
 253 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 254 {
 255         return xfrm_input(skb, nexthdr, 0, -1);
 256 }
 257 EXPORT_SYMBOL(xfrm_input_resume);
 258
 259 void __init xfrm_input_init(void)
 260 {
 261         secpath_cachep = kmem_cache_create("secpath_cache",
 262                                            sizeof(struct sec_path),
 263                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 264                                            NULL);
 265 }