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/bottom_half.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/percpu.h>
  16 #include <net/dst.h>
  17 #include <net/ip.h>
  18 #include <net/xfrm.h>
  19
  20 struct xfrm_trans_tasklet {
  21         struct tasklet_struct tasklet;
  22         struct sk_buff_head queue;
  23 };
  24
  25 struct xfrm_trans_cb {
  26         int (*finish)(struct sk_buff *skb);
  27 };
  28
  29 #define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))
  30
  31 static struct kmem_cache *secpath_cachep __read_mostly;
  32
  33 static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);
  34
  35 void __secpath_destroy(struct sec_path *sp)
  36 {
  37         int i;
  38         for (i = 0; i < sp->len; i++)
  39                 xfrm_state_put(sp->xvec[i]);
  40         kmem_cache_free(secpath_cachep, sp);
  41 }
  42 EXPORT_SYMBOL(__secpath_destroy);
  43
  44 struct sec_path *secpath_dup(struct sec_path *src)
  45 {
  46         struct sec_path *sp;
  47
  48         sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
  49         if (!sp)
  50                 return NULL;
  51
  52         sp->len = 0;
  53         if (src) {
  54                 int i;
  55
  56                 memcpy(sp, src, sizeof(*sp));
  57                 for (i = 0; i < sp->len; i++)
  58                         xfrm_state_hold(sp->xvec[i]);
  59         }
  60         atomic_set(&sp->refcnt, 1);
  61         return sp;
  62 }
  63 EXPORT_SYMBOL(secpath_dup);
  64
  65 /* Fetch spi and seq from ipsec header */
  66
  67 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
  68 {
  69         int offset, offset_seq;
  70         int hlen;
  71
  72         switch (nexthdr) {
  73         case IPPROTO_AH:
  74                 hlen = sizeof(struct ip_auth_hdr);
  75                 offset = offsetof(struct ip_auth_hdr, spi);
  76                 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
  77                 break;
  78         case IPPROTO_ESP:
  79                 hlen = sizeof(struct ip_esp_hdr);
  80                 offset = offsetof(struct ip_esp_hdr, spi);
  81                 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
  82                 break;
  83         case IPPROTO_COMP:
  84                 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
  85                         return -EINVAL;
  86                 *spi = htonl(ntohs(*(__be16*)(skb_transport_header(skb) + 2)));
  87                 *seq = 0;
  88                 return 0;
  89         default:
  90                 return 1;
  91         }
  92
  93         if (!pskb_may_pull(skb, hlen))
  94                 return -EINVAL;
  95
  96         *spi = *(__be32*)(skb_transport_header(skb) + offset);
  97         *seq = *(__be32*)(skb_transport_header(skb) + offset_seq);
  98         return 0;
  99 }
 100
 101 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 102 {
 103         struct xfrm_mode *inner_mode = x->inner_mode;
 104         int err;
 105
 106         err = x->outer_mode->afinfo->extract_input(x, skb);
 107         if (err)
 108                 return err;
 109
 110         if (x->sel.family == AF_UNSPEC) {
 111                 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 112                 if (inner_mode == NULL)
 113                         return -EAFNOSUPPORT;
 114         }
 115
 116         skb->protocol = inner_mode->afinfo->eth_proto;
 117         return inner_mode->input2(x, skb);
 118 }
 119 EXPORT_SYMBOL(xfrm_prepare_input);
 120
 121 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 122 {
 123         struct net *net = dev_net(skb->dev);
 124         int err;
 125         __be32 seq;
 126         __be32 seq_hi;
 127         struct xfrm_state *x;
 128         xfrm_address_t *daddr;
 129         struct xfrm_mode *inner_mode;
 130         unsigned int family;
 131         int decaps = 0;
 132         int async = 0;
 133
 134         /* A negative encap_type indicates async resumption. */
 135         if (encap_type < 0) {
 136                 async = 1;
 137                 x = xfrm_input_state(skb);
 138                 seq = XFRM_SKB_CB(skb)->seq.input.low;
 139                 goto resume;
 140         }
 141
 142         /* Allocate new secpath or COW existing one. */
 143         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
 144                 struct sec_path *sp;
 145
 146                 sp = secpath_dup(skb->sp);
 147                 if (!sp) {
 148                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 149                         goto drop;
 150                 }
 151                 if (skb->sp)
 152                         secpath_put(skb->sp);
 153                 skb->sp = sp;
 154         }
 155
 156         daddr = (xfrm_address_t *)(skb_network_header(skb) +
 157                                    XFRM_SPI_SKB_CB(skb)->daddroff);
 158         family = XFRM_SPI_SKB_CB(skb)->family;
 159
 160         seq = 0;
 161         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 162                 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 163                 goto drop;
 164         }
 165
 166         do {
 167                 if (skb->sp->len == XFRM_MAX_DEPTH) {
 168                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 169                         goto drop;
 170                 }
 171
 172                 x = xfrm_state_lookup(net, skb->mark, daddr, spi, nexthdr, family);
 173                 if (x == NULL) {
 174                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
 175                         xfrm_audit_state_notfound(skb, family, spi, seq);
 176                         goto drop;
 177                 }
 178
 179                 skb->sp->xvec[skb->sp->len++] = x;
 180
 181                 spin_lock(&x->lock);
 182                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 183                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEINVALID);
 184                         goto drop_unlock;
 185                 }
 186
 187                 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 188                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
 189                         goto drop_unlock;
 190                 }
 191
 192                 if (x->repl->check(x, skb, seq)) {
 193                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 194                         goto drop_unlock;
 195                 }
 196
 197                 if (xfrm_state_check_expire(x)) {
 198                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
 199                         goto drop_unlock;
 200                 }
 201
 202                 spin_unlock(&x->lock);
 203
 204                 seq_hi = htonl(xfrm_replay_seqhi(x, seq));
 205
 206                 XFRM_SKB_CB(skb)->seq.input.low = seq;
 207                 XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
 208
 209                 skb_dst_force(skb);
 210                 dev_hold(skb->dev);
 211
 212                 nexthdr = x->type->input(x, skb);
 213
 214                 if (nexthdr == -EINPROGRESS)
 215                         return 0;
 216
 217 resume:
 218                 dev_put(skb->dev);
 219
 220                 spin_lock(&x->lock);
 221                 if (nexthdr <= 0) {
 222                         if (nexthdr == -EBADMSG) {
 223                                 xfrm_audit_state_icvfail(x, skb,
 224                                                          x->type->proto);
 225                                 x->stats.integrity_failed++;
 226                         }
 227                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 228                         goto drop_unlock;
 229                 }
 230
 231                 /* only the first xfrm gets the encap type */
 232                 encap_type = 0;
 233
 234                 if (async && x->repl->recheck(x, skb, seq)) {
 235                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 236                         goto drop_unlock;
 237                 }
 238
 239                 x->repl->advance(x, seq);
 240
 241                 x->curlft.bytes += skb->len;
 242                 x->curlft.packets++;
 243
 244                 spin_unlock(&x->lock);
 245
 246                 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
 247
 248                 inner_mode = x->inner_mode;
 249
 250                 if (x->sel.family == AF_UNSPEC) {
 251                         inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 252                         if (inner_mode == NULL)
 253                                 goto drop;
 254                 }
 255
 256                 if (inner_mode->input(x, skb)) {
 257                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 258                         goto drop;
 259                 }
 260
 261                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
 262                         decaps = 1;
 263                         break;
 264                 }
 265
 266                 /*
 267                  * We need the inner address.  However, we only get here for
 268                  * transport mode so the outer address is identical.
 269                  */
 270                 daddr = &x->id.daddr;
 271                 family = x->outer_mode->afinfo->family;
 272
 273                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 274                 if (err < 0) {
 275                         XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 276                         goto drop;
 277                 }
 278         } while (!err);
 279
 280         nf_reset(skb);
 281
 282         if (decaps) {
 283                 skb_dst_drop(skb);
 284                 netif_rx(skb);
 285                 return 0;
 286         } else {
 287                 return x->inner_mode->afinfo->transport_finish(skb, async);
 288         }
 289
 290 drop_unlock:
 291         spin_unlock(&x->lock);
 292 drop:
 293         kfree_skb(skb);
 294         return 0;
 295 }
 296 EXPORT_SYMBOL(xfrm_input);
 297
 298 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 299 {
 300         return xfrm_input(skb, nexthdr, 0, -1);
 301 }
 302 EXPORT_SYMBOL(xfrm_input_resume);
 303
 304 static void xfrm_trans_reinject(unsigned long data)
 305 {
 306         struct xfrm_trans_tasklet *trans = (void *)data;
 307         struct sk_buff_head queue;
 308         struct sk_buff *skb;
 309
 310         __skb_queue_head_init(&queue);
 311         skb_queue_splice_init(&trans->queue, &queue);
 312
 313         while ((skb = __skb_dequeue(&queue)))
 314                 XFRM_TRANS_SKB_CB(skb)->finish(skb);
 315 }
 316
 317 int xfrm_trans_queue(struct sk_buff *skb, int (*finish)(struct sk_buff *))
 318 {
 319         struct xfrm_trans_tasklet *trans;
 320
 321         trans = this_cpu_ptr(&xfrm_trans_tasklet);
 322
 323         if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
 324                 return -ENOBUFS;
 325
 326         XFRM_TRANS_SKB_CB(skb)->finish = finish;
 327         __skb_queue_tail(&trans->queue, skb);
 328         tasklet_schedule(&trans->tasklet);
 329         return 0;
 330 }
 331 EXPORT_SYMBOL(xfrm_trans_queue);
 332
 333 void __init xfrm_input_init(void)
 334 {
 335         int i;
 336
 337         secpath_cachep = kmem_cache_create("secpath_cache",
 338                                            sizeof(struct sec_path),
 339                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 340                                            NULL);
 341
 342         for_each_possible_cpu(i) {
 343                 struct xfrm_trans_tasklet *trans;
 344
 345                 trans = &per_cpu(xfrm_trans_tasklet, i);
 346                 __skb_queue_head_init(&trans->queue);
 347                 tasklet_init(&trans->tasklet, xfrm_trans_reinject,
 348                              (unsigned long)trans);
 349         }
 350 }