git.oblomov.eu Git - linux-2.6/blob - net/xfrm/xfrm_policy.c

   1 /*
   2  * xfrm_policy.c
   3  *
   4  * Changes:
   5  *      Mitsuru KANDA @USAGI
   6  *      Kazunori MIYAZAWA @USAGI
   7  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
   8  *              IPv6 support
   9  *      Kazunori MIYAZAWA @USAGI
  10  *      YOSHIFUJI Hideaki
  11  *              Split up af-specific portion
  12  *      Derek Atkins <derek@ihtfp.com>          Add the post_input processor
  13  *
  14  */
  15
  16 #include <asm/bug.h>
  17 #include <linux/config.h>
  18 #include <linux/slab.h>
  19 #include <linux/kmod.h>
  20 #include <linux/list.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/notifier.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/module.h>
  26 #include <net/xfrm.h>
  27 #include <net/ip.h>
  28
  29 DECLARE_MUTEX(xfrm_cfg_sem);
  30 EXPORT_SYMBOL(xfrm_cfg_sem);
  31
  32 static DEFINE_RWLOCK(xfrm_policy_lock);
  33
  34 struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
  35 EXPORT_SYMBOL(xfrm_policy_list);
  36
  37 static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
  38 static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
  39
  40 static kmem_cache_t *xfrm_dst_cache __read_mostly;
  41
  42 static struct work_struct xfrm_policy_gc_work;
  43 static struct list_head xfrm_policy_gc_list =
  44         LIST_HEAD_INIT(xfrm_policy_gc_list);
  45 static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
  46
  47 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
  48 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
  49
  50 int xfrm_register_type(struct xfrm_type *type, unsigned short family)
  51 {
  52         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
  53         struct xfrm_type_map *typemap;
  54         int err = 0;
  55
  56         if (unlikely(afinfo == NULL))
  57                 return -EAFNOSUPPORT;
  58         typemap = afinfo->type_map;
  59
  60         write_lock(&typemap->lock);
  61         if (likely(typemap->map[type->proto] == NULL))
  62                 typemap->map[type->proto] = type;
  63         else
  64                 err = -EEXIST;
  65         write_unlock(&typemap->lock);
  66         xfrm_policy_put_afinfo(afinfo);
  67         return err;
  68 }
  69 EXPORT_SYMBOL(xfrm_register_type);
  70
  71 int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
  72 {
  73         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
  74         struct xfrm_type_map *typemap;
  75         int err = 0;
  76
  77         if (unlikely(afinfo == NULL))
  78                 return -EAFNOSUPPORT;
  79         typemap = afinfo->type_map;
  80
  81         write_lock(&typemap->lock);
  82         if (unlikely(typemap->map[type->proto] != type))
  83                 err = -ENOENT;
  84         else
  85                 typemap->map[type->proto] = NULL;
  86         write_unlock(&typemap->lock);
  87         xfrm_policy_put_afinfo(afinfo);
  88         return err;
  89 }
  90 EXPORT_SYMBOL(xfrm_unregister_type);
  91
  92 struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
  93 {
  94         struct xfrm_policy_afinfo *afinfo;
  95         struct xfrm_type_map *typemap;
  96         struct xfrm_type *type;
  97         int modload_attempted = 0;
  98
  99 retry:
 100         afinfo = xfrm_policy_get_afinfo(family);
 101         if (unlikely(afinfo == NULL))
 102                 return NULL;
 103         typemap = afinfo->type_map;
 104
 105         read_lock(&typemap->lock);
 106         type = typemap->map[proto];
 107         if (unlikely(type && !try_module_get(type->owner)))
 108                 type = NULL;
 109         read_unlock(&typemap->lock);
 110         if (!type && !modload_attempted) {
 111                 xfrm_policy_put_afinfo(afinfo);
 112                 request_module("xfrm-type-%d-%d",
 113                                (int) family, (int) proto);
 114                 modload_attempted = 1;
 115                 goto retry;
 116         }
 117
 118         xfrm_policy_put_afinfo(afinfo);
 119         return type;
 120 }
 121
 122 int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl,
 123                     unsigned short family)
 124 {
 125         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 126         int err = 0;
 127
 128         if (unlikely(afinfo == NULL))
 129                 return -EAFNOSUPPORT;
 130
 131         if (likely(afinfo->dst_lookup != NULL))
 132                 err = afinfo->dst_lookup(dst, fl);
 133         else
 134                 err = -EINVAL;
 135         xfrm_policy_put_afinfo(afinfo);
 136         return err;
 137 }
 138 EXPORT_SYMBOL(xfrm_dst_lookup);
 139
 140 void xfrm_put_type(struct xfrm_type *type)
 141 {
 142         module_put(type->owner);
 143 }
 144
 145 static inline unsigned long make_jiffies(long secs)
 146 {
 147         if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
 148                 return MAX_SCHEDULE_TIMEOUT-1;
 149         else
 150                 return secs*HZ;
 151 }
 152
 153 static void xfrm_policy_timer(unsigned long data)
 154 {
 155         struct xfrm_policy *xp = (struct xfrm_policy*)data;
 156         unsigned long now = (unsigned long)xtime.tv_sec;
 157         long next = LONG_MAX;
 158         int warn = 0;
 159         int dir;
 160
 161         read_lock(&xp->lock);
 162
 163         if (xp->dead)
 164                 goto out;
 165
 166         dir = xfrm_policy_id2dir(xp->index);
 167
 168         if (xp->lft.hard_add_expires_seconds) {
 169                 long tmo = xp->lft.hard_add_expires_seconds +
 170                         xp->curlft.add_time - now;
 171                 if (tmo <= 0)
 172                         goto expired;
 173                 if (tmo < next)
 174                         next = tmo;
 175         }
 176         if (xp->lft.hard_use_expires_seconds) {
 177                 long tmo = xp->lft.hard_use_expires_seconds +
 178                         (xp->curlft.use_time ? : xp->curlft.add_time) - now;
 179                 if (tmo <= 0)
 180                         goto expired;
 181                 if (tmo < next)
 182                         next = tmo;
 183         }
 184         if (xp->lft.soft_add_expires_seconds) {
 185                 long tmo = xp->lft.soft_add_expires_seconds +
 186                         xp->curlft.add_time - now;
 187                 if (tmo <= 0) {
 188                         warn = 1;
 189                         tmo = XFRM_KM_TIMEOUT;
 190                 }
 191                 if (tmo < next)
 192                         next = tmo;
 193         }
 194         if (xp->lft.soft_use_expires_seconds) {
 195                 long tmo = xp->lft.soft_use_expires_seconds +
 196                         (xp->curlft.use_time ? : xp->curlft.add_time) - now;
 197                 if (tmo <= 0) {
 198                         warn = 1;
 199                         tmo = XFRM_KM_TIMEOUT;
 200                 }
 201                 if (tmo < next)
 202                         next = tmo;
 203         }
 204
 205         if (warn)
 206                 km_policy_expired(xp, dir, 0);
 207         if (next != LONG_MAX &&
 208             !mod_timer(&xp->timer, jiffies + make_jiffies(next)))
 209                 xfrm_pol_hold(xp);
 210
 211 out:
 212         read_unlock(&xp->lock);
 213         xfrm_pol_put(xp);
 214         return;
 215
 216 expired:
 217         read_unlock(&xp->lock);
 218         if (!xfrm_policy_delete(xp, dir))
 219                 km_policy_expired(xp, dir, 1);
 220         xfrm_pol_put(xp);
 221 }
 222
 223
 224 /* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
 225  * SPD calls.
 226  */
 227
 228 struct xfrm_policy *xfrm_policy_alloc(gfp_t gfp)
 229 {
 230         struct xfrm_policy *policy;
 231
 232         policy = kmalloc(sizeof(struct xfrm_policy), gfp);
 233
 234         if (policy) {
 235                 memset(policy, 0, sizeof(struct xfrm_policy));
 236                 atomic_set(&policy->refcnt, 1);
 237                 rwlock_init(&policy->lock);
 238                 init_timer(&policy->timer);
 239                 policy->timer.data = (unsigned long)policy;
 240                 policy->timer.function = xfrm_policy_timer;
 241         }
 242         return policy;
 243 }
 244 EXPORT_SYMBOL(xfrm_policy_alloc);
 245
 246 /* Destroy xfrm_policy: descendant resources must be released to this moment. */
 247
 248 void __xfrm_policy_destroy(struct xfrm_policy *policy)
 249 {
 250         if (!policy->dead)
 251                 BUG();
 252
 253         if (policy->bundles)
 254                 BUG();
 255
 256         if (del_timer(&policy->timer))
 257                 BUG();
 258
 259         kfree(policy);
 260 }
 261 EXPORT_SYMBOL(__xfrm_policy_destroy);
 262
 263 static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
 264 {
 265         struct dst_entry *dst;
 266
 267         while ((dst = policy->bundles) != NULL) {
 268                 policy->bundles = dst->next;
 269                 dst_free(dst);
 270         }
 271
 272         if (del_timer(&policy->timer))
 273                 atomic_dec(&policy->refcnt);
 274
 275         if (atomic_read(&policy->refcnt) > 1)
 276                 flow_cache_flush();
 277
 278         xfrm_pol_put(policy);
 279 }
 280
 281 static void xfrm_policy_gc_task(void *data)
 282 {
 283         struct xfrm_policy *policy;
 284         struct list_head *entry, *tmp;
 285         struct list_head gc_list = LIST_HEAD_INIT(gc_list);
 286
 287         spin_lock_bh(&xfrm_policy_gc_lock);
 288         list_splice_init(&xfrm_policy_gc_list, &gc_list);
 289         spin_unlock_bh(&xfrm_policy_gc_lock);
 290
 291         list_for_each_safe(entry, tmp, &gc_list) {
 292                 policy = list_entry(entry, struct xfrm_policy, list);
 293                 xfrm_policy_gc_kill(policy);
 294         }
 295 }
 296
 297 /* Rule must be locked. Release descentant resources, announce
 298  * entry dead. The rule must be unlinked from lists to the moment.
 299  */
 300
 301 static void xfrm_policy_kill(struct xfrm_policy *policy)
 302 {
 303         int dead;
 304
 305         write_lock_bh(&policy->lock);
 306         dead = policy->dead;
 307         policy->dead = 1;
 308         write_unlock_bh(&policy->lock);
 309
 310         if (unlikely(dead)) {
 311                 WARN_ON(1);
 312                 return;
 313         }
 314
 315         spin_lock(&xfrm_policy_gc_lock);
 316         list_add(&policy->list, &xfrm_policy_gc_list);
 317         spin_unlock(&xfrm_policy_gc_lock);
 318
 319         schedule_work(&xfrm_policy_gc_work);
 320 }
 321
 322 /* Generate new index... KAME seems to generate them ordered by cost
 323  * of an absolute inpredictability of ordering of rules. This will not pass. */
 324 static u32 xfrm_gen_index(int dir)
 325 {
 326         u32 idx;
 327         struct xfrm_policy *p;
 328         static u32 idx_generator;
 329
 330         for (;;) {
 331                 idx = (idx_generator | dir);
 332                 idx_generator += 8;
 333                 if (idx == 0)
 334                         idx = 8;
 335                 for (p = xfrm_policy_list[dir]; p; p = p->next) {
 336                         if (p->index == idx)
 337                                 break;
 338                 }
 339                 if (!p)
 340                         return idx;
 341         }
 342 }
 343
 344 int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
 345 {
 346         struct xfrm_policy *pol, **p;
 347         struct xfrm_policy *delpol = NULL;
 348         struct xfrm_policy **newpos = NULL;
 349
 350         write_lock_bh(&xfrm_policy_lock);
 351         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL;) {
 352                 if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0) {
 353                         if (excl) {
 354                                 write_unlock_bh(&xfrm_policy_lock);
 355                                 return -EEXIST;
 356                         }
 357                         *p = pol->next;
 358                         delpol = pol;
 359                         if (policy->priority > pol->priority)
 360                                 continue;
 361                 } else if (policy->priority >= pol->priority) {
 362                         p = &pol->next;
 363                         continue;
 364                 }
 365                 if (!newpos)
 366                         newpos = p;
 367                 if (delpol)
 368                         break;
 369                 p = &pol->next;
 370         }
 371         if (newpos)
 372                 p = newpos;
 373         xfrm_pol_hold(policy);
 374         policy->next = *p;
 375         *p = policy;
 376         atomic_inc(&flow_cache_genid);
 377         policy->index = delpol ? delpol->index : xfrm_gen_index(dir);
 378         policy->curlft.add_time = (unsigned long)xtime.tv_sec;
 379         policy->curlft.use_time = 0;
 380         if (!mod_timer(&policy->timer, jiffies + HZ))
 381                 xfrm_pol_hold(policy);
 382         write_unlock_bh(&xfrm_policy_lock);
 383
 384         if (delpol) {
 385                 xfrm_policy_kill(delpol);
 386         }
 387         return 0;
 388 }
 389 EXPORT_SYMBOL(xfrm_policy_insert);
 390
 391 struct xfrm_policy *xfrm_policy_bysel(int dir, struct xfrm_selector *sel,
 392                                       int delete)
 393 {
 394         struct xfrm_policy *pol, **p;
 395
 396         write_lock_bh(&xfrm_policy_lock);
 397         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
 398                 if (memcmp(sel, &pol->selector, sizeof(*sel)) == 0) {
 399                         xfrm_pol_hold(pol);
 400                         if (delete)
 401                                 *p = pol->next;
 402                         break;
 403                 }
 404         }
 405         write_unlock_bh(&xfrm_policy_lock);
 406
 407         if (pol && delete) {
 408                 atomic_inc(&flow_cache_genid);
 409                 xfrm_policy_kill(pol);
 410         }
 411         return pol;
 412 }
 413 EXPORT_SYMBOL(xfrm_policy_bysel);
 414
 415 struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete)
 416 {
 417         struct xfrm_policy *pol, **p;
 418
 419         write_lock_bh(&xfrm_policy_lock);
 420         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
 421                 if (pol->index == id) {
 422                         xfrm_pol_hold(pol);
 423                         if (delete)
 424                                 *p = pol->next;
 425                         break;
 426                 }
 427         }
 428         write_unlock_bh(&xfrm_policy_lock);
 429
 430         if (pol && delete) {
 431                 atomic_inc(&flow_cache_genid);
 432                 xfrm_policy_kill(pol);
 433         }
 434         return pol;
 435 }
 436 EXPORT_SYMBOL(xfrm_policy_byid);
 437
 438 void xfrm_policy_flush(void)
 439 {
 440         struct xfrm_policy *xp;
 441         int dir;
 442
 443         write_lock_bh(&xfrm_policy_lock);
 444         for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
 445                 while ((xp = xfrm_policy_list[dir]) != NULL) {
 446                         xfrm_policy_list[dir] = xp->next;
 447                         write_unlock_bh(&xfrm_policy_lock);
 448
 449                         xfrm_policy_kill(xp);
 450
 451                         write_lock_bh(&xfrm_policy_lock);
 452                 }
 453         }
 454         atomic_inc(&flow_cache_genid);
 455         write_unlock_bh(&xfrm_policy_lock);
 456 }
 457 EXPORT_SYMBOL(xfrm_policy_flush);
 458
 459 int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*),
 460                      void *data)
 461 {
 462         struct xfrm_policy *xp;
 463         int dir;
 464         int count = 0;
 465         int error = 0;
 466
 467         read_lock_bh(&xfrm_policy_lock);
 468         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
 469                 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next)
 470                         count++;
 471         }
 472
 473         if (count == 0) {
 474                 error = -ENOENT;
 475                 goto out;
 476         }
 477
 478         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
 479                 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next) {
 480                         error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
 481                         if (error)
 482                                 goto out;
 483                 }
 484         }
 485
 486 out:
 487         read_unlock_bh(&xfrm_policy_lock);
 488         return error;
 489 }
 490 EXPORT_SYMBOL(xfrm_policy_walk);
 491
 492 /* Find policy to apply to this flow. */
 493
 494 static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
 495                                void **objp, atomic_t **obj_refp)
 496 {
 497         struct xfrm_policy *pol;
 498
 499         read_lock_bh(&xfrm_policy_lock);
 500         for (pol = xfrm_policy_list[dir]; pol; pol = pol->next) {
 501                 struct xfrm_selector *sel = &pol->selector;
 502                 int match;
 503
 504                 if (pol->family != family)
 505                         continue;
 506
 507                 match = xfrm_selector_match(sel, fl, family);
 508                 if (match) {
 509                         xfrm_pol_hold(pol);
 510                         break;
 511                 }
 512         }
 513         read_unlock_bh(&xfrm_policy_lock);
 514         if ((*objp = (void *) pol) != NULL)
 515                 *obj_refp = &pol->refcnt;
 516 }
 517
 518 static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl)
 519 {
 520         struct xfrm_policy *pol;
 521
 522         read_lock_bh(&xfrm_policy_lock);
 523         if ((pol = sk->sk_policy[dir]) != NULL) {
 524                 int match = xfrm_selector_match(&pol->selector, fl,
 525                                                 sk->sk_family);
 526                 if (match)
 527                         xfrm_pol_hold(pol);
 528                 else
 529                         pol = NULL;
 530         }
 531         read_unlock_bh(&xfrm_policy_lock);
 532         return pol;
 533 }
 534
 535 static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
 536 {
 537         pol->next = xfrm_policy_list[dir];
 538         xfrm_policy_list[dir] = pol;
 539         xfrm_pol_hold(pol);
 540 }
 541
 542 static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
 543                                                 int dir)
 544 {
 545         struct xfrm_policy **polp;
 546
 547         for (polp = &xfrm_policy_list[dir];
 548              *polp != NULL; polp = &(*polp)->next) {
 549                 if (*polp == pol) {
 550                         *polp = pol->next;
 551                         return pol;
 552                 }
 553         }
 554         return NULL;
 555 }
 556
 557 int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
 558 {
 559         write_lock_bh(&xfrm_policy_lock);
 560         pol = __xfrm_policy_unlink(pol, dir);
 561         write_unlock_bh(&xfrm_policy_lock);
 562         if (pol) {
 563                 if (dir < XFRM_POLICY_MAX)
 564                         atomic_inc(&flow_cache_genid);
 565                 xfrm_policy_kill(pol);
 566                 return 0;
 567         }
 568         return -ENOENT;
 569 }
 570
 571 int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
 572 {
 573         struct xfrm_policy *old_pol;
 574
 575         write_lock_bh(&xfrm_policy_lock);
 576         old_pol = sk->sk_policy[dir];
 577         sk->sk_policy[dir] = pol;
 578         if (pol) {
 579                 pol->curlft.add_time = (unsigned long)xtime.tv_sec;
 580                 pol->index = xfrm_gen_index(XFRM_POLICY_MAX+dir);
 581                 __xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
 582         }
 583         if (old_pol)
 584                 __xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
 585         write_unlock_bh(&xfrm_policy_lock);
 586
 587         if (old_pol) {
 588                 xfrm_policy_kill(old_pol);
 589         }
 590         return 0;
 591 }
 592
 593 static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
 594 {
 595         struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
 596
 597         if (newp) {
 598                 newp->selector = old->selector;
 599                 newp->lft = old->lft;
 600                 newp->curlft = old->curlft;
 601                 newp->action = old->action;
 602                 newp->flags = old->flags;
 603                 newp->xfrm_nr = old->xfrm_nr;
 604                 newp->index = old->index;
 605                 memcpy(newp->xfrm_vec, old->xfrm_vec,
 606                        newp->xfrm_nr*sizeof(struct xfrm_tmpl));
 607                 write_lock_bh(&xfrm_policy_lock);
 608                 __xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
 609                 write_unlock_bh(&xfrm_policy_lock);
 610                 xfrm_pol_put(newp);
 611         }
 612         return newp;
 613 }
 614
 615 int __xfrm_sk_clone_policy(struct sock *sk)
 616 {
 617         struct xfrm_policy *p0 = sk->sk_policy[0],
 618                            *p1 = sk->sk_policy[1];
 619
 620         sk->sk_policy[0] = sk->sk_policy[1] = NULL;
 621         if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
 622                 return -ENOMEM;
 623         if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
 624                 return -ENOMEM;
 625         return 0;
 626 }
 627
 628 /* Resolve list of templates for the flow, given policy. */
 629
 630 static int
 631 xfrm_tmpl_resolve(struct xfrm_policy *policy, struct flowi *fl,
 632                   struct xfrm_state **xfrm,
 633                   unsigned short family)
 634 {
 635         int nx;
 636         int i, error;
 637         xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
 638         xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
 639
 640         for (nx=0, i = 0; i < policy->xfrm_nr; i++) {
 641                 struct xfrm_state *x;
 642                 xfrm_address_t *remote = daddr;
 643                 xfrm_address_t *local  = saddr;
 644                 struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
 645
 646                 if (tmpl->mode) {
 647                         remote = &tmpl->id.daddr;
 648                         local = &tmpl->saddr;
 649                 }
 650
 651                 x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
 652
 653                 if (x && x->km.state == XFRM_STATE_VALID) {
 654                         xfrm[nx++] = x;
 655                         daddr = remote;
 656                         saddr = local;
 657                         continue;
 658                 }
 659                 if (x) {
 660                         error = (x->km.state == XFRM_STATE_ERROR ?
 661                                  -EINVAL : -EAGAIN);
 662                         xfrm_state_put(x);
 663                 }
 664
 665                 if (!tmpl->optional)
 666                         goto fail;
 667         }
 668         return nx;
 669
 670 fail:
 671         for (nx--; nx>=0; nx--)
 672                 xfrm_state_put(xfrm[nx]);
 673         return error;
 674 }
 675
 676 /* Check that the bundle accepts the flow and its components are
 677  * still valid.
 678  */
 679
 680 static struct dst_entry *
 681 xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
 682 {
 683         struct dst_entry *x;
 684         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 685         if (unlikely(afinfo == NULL))
 686                 return ERR_PTR(-EINVAL);
 687         x = afinfo->find_bundle(fl, policy);
 688         xfrm_policy_put_afinfo(afinfo);
 689         return x;
 690 }
 691
 692 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 693  * all the metrics... Shortly, bundle a bundle.
 694  */
 695
 696 static int
 697 xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 698                    struct flowi *fl, struct dst_entry **dst_p,
 699                    unsigned short family)
 700 {
 701         int err;
 702         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 703         if (unlikely(afinfo == NULL))
 704                 return -EINVAL;
 705         err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
 706         xfrm_policy_put_afinfo(afinfo);
 707         return err;
 708 }
 709
 710 static inline int policy_to_flow_dir(int dir)
 711 {
 712         if (XFRM_POLICY_IN == FLOW_DIR_IN &&
 713             XFRM_POLICY_OUT == FLOW_DIR_OUT &&
 714             XFRM_POLICY_FWD == FLOW_DIR_FWD)
 715                 return dir;
 716         switch (dir) {
 717         default:
 718         case XFRM_POLICY_IN:
 719                 return FLOW_DIR_IN;
 720         case XFRM_POLICY_OUT:
 721                 return FLOW_DIR_OUT;
 722         case XFRM_POLICY_FWD:
 723                 return FLOW_DIR_FWD;
 724         };
 725 }
 726
 727 static int stale_bundle(struct dst_entry *dst);
 728
 729 /* Main function: finds/creates a bundle for given flow.
 730  *
 731  * At the moment we eat a raw IP route. Mostly to speed up lookups
 732  * on interfaces with disabled IPsec.
 733  */
 734 int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 735                 struct sock *sk, int flags)
 736 {
 737         struct xfrm_policy *policy;
 738         struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
 739         struct dst_entry *dst, *dst_orig = *dst_p;
 740         int nx = 0;
 741         int err;
 742         u32 genid;
 743         u16 family = dst_orig->ops->family;
 744 restart:
 745         genid = atomic_read(&flow_cache_genid);
 746         policy = NULL;
 747         if (sk && sk->sk_policy[1])
 748                 policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
 749
 750         if (!policy) {
 751                 /* To accelerate a bit...  */
 752                 if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
 753                         return 0;
 754
 755                 policy = flow_cache_lookup(fl, family,
 756                                            policy_to_flow_dir(XFRM_POLICY_OUT),
 757                                            xfrm_policy_lookup);
 758         }
 759
 760         if (!policy)
 761                 return 0;
 762
 763         policy->curlft.use_time = (unsigned long)xtime.tv_sec;
 764
 765         switch (policy->action) {
 766         case XFRM_POLICY_BLOCK:
 767                 /* Prohibit the flow */
 768                 err = -EPERM;
 769                 goto error;
 770
 771         case XFRM_POLICY_ALLOW:
 772                 if (policy->xfrm_nr == 0) {
 773                         /* Flow passes not transformed. */
 774                         xfrm_pol_put(policy);
 775                         return 0;
 776                 }
 777
 778                 /* Try to find matching bundle.
 779                  *
 780                  * LATER: help from flow cache. It is optional, this
 781                  * is required only for output policy.
 782                  */
 783                 dst = xfrm_find_bundle(fl, policy, family);
 784                 if (IS_ERR(dst)) {
 785                         err = PTR_ERR(dst);
 786                         goto error;
 787                 }
 788
 789                 if (dst)
 790                         break;
 791
 792                 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
 793
 794                 if (unlikely(nx<0)) {
 795                         err = nx;
 796                         if (err == -EAGAIN && flags) {
 797                                 DECLARE_WAITQUEUE(wait, current);
 798
 799                                 add_wait_queue(&km_waitq, &wait);
 800                                 set_current_state(TASK_INTERRUPTIBLE);
 801                                 schedule();
 802                                 set_current_state(TASK_RUNNING);
 803                                 remove_wait_queue(&km_waitq, &wait);
 804
 805                                 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
 806
 807                                 if (nx == -EAGAIN && signal_pending(current)) {
 808                                         err = -ERESTART;
 809                                         goto error;
 810                                 }
 811                                 if (nx == -EAGAIN ||
 812                                     genid != atomic_read(&flow_cache_genid)) {
 813                                         xfrm_pol_put(policy);
 814                                         goto restart;
 815                                 }
 816                                 err = nx;
 817                         }
 818                         if (err < 0)
 819                                 goto error;
 820                 }
 821                 if (nx == 0) {
 822                         /* Flow passes not transformed. */
 823                         xfrm_pol_put(policy);
 824                         return 0;
 825                 }
 826
 827                 dst = dst_orig;
 828                 err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
 829
 830                 if (unlikely(err)) {
 831                         int i;
 832                         for (i=0; i<nx; i++)
 833                                 xfrm_state_put(xfrm[i]);
 834                         goto error;
 835                 }
 836
 837                 write_lock_bh(&policy->lock);
 838                 if (unlikely(policy->dead || stale_bundle(dst))) {
 839                         /* Wow! While we worked on resolving, this
 840                          * policy has gone. Retry. It is not paranoia,
 841                          * we just cannot enlist new bundle to dead object.
 842                          * We can't enlist stable bundles either.
 843                          */
 844                         write_unlock_bh(&policy->lock);
 845
 846                         xfrm_pol_put(policy);
 847                         if (dst)
 848                                 dst_free(dst);
 849                         goto restart;
 850                 }
 851                 dst->next = policy->bundles;
 852                 policy->bundles = dst;
 853                 dst_hold(dst);
 854                 write_unlock_bh(&policy->lock);
 855         }
 856         *dst_p = dst;
 857         dst_release(dst_orig);
 858         xfrm_pol_put(policy);
 859         return 0;
 860
 861 error:
 862         dst_release(dst_orig);
 863         xfrm_pol_put(policy);
 864         *dst_p = NULL;
 865         return err;
 866 }
 867 EXPORT_SYMBOL(xfrm_lookup);
 868
 869 /* When skb is transformed back to its "native" form, we have to
 870  * check policy restrictions. At the moment we make this in maximally
 871  * stupid way. Shame on me. :-) Of course, connected sockets must
 872  * have policy cached at them.
 873  */
 874
 875 static inline int
 876 xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x,
 877               unsigned short family)
 878 {
 879         if (xfrm_state_kern(x))
 880                 return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, family);
 881         return  x->id.proto == tmpl->id.proto &&
 882                 (x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
 883                 (x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
 884                 x->props.mode == tmpl->mode &&
 885                 (tmpl->aalgos & (1<<x->props.aalgo)) &&
 886                 !(x->props.mode && xfrm_state_addr_cmp(tmpl, x, family));
 887 }
 888
 889 static inline int
 890 xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
 891                unsigned short family)
 892 {
 893         int idx = start;
 894
 895         if (tmpl->optional) {
 896                 if (!tmpl->mode)
 897                         return start;
 898         } else
 899                 start = -1;
 900         for (; idx < sp->len; idx++) {
 901                 if (xfrm_state_ok(tmpl, sp->x[idx].xvec, family))
 902                         return ++idx;
 903                 if (sp->x[idx].xvec->props.mode)
 904                         break;
 905         }
 906         return start;
 907 }
 908
 909 static int
 910 _decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
 911 {
 912         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 913
 914         if (unlikely(afinfo == NULL))
 915                 return -EAFNOSUPPORT;
 916
 917         afinfo->decode_session(skb, fl);
 918         xfrm_policy_put_afinfo(afinfo);
 919         return 0;
 920 }
 921
 922 static inline int secpath_has_tunnel(struct sec_path *sp, int k)
 923 {
 924         for (; k < sp->len; k++) {
 925                 if (sp->x[k].xvec->props.mode)
 926                         return 1;
 927         }
 928
 929         return 0;
 930 }
 931
 932 int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
 933                         unsigned short family)
 934 {
 935         struct xfrm_policy *pol;
 936         struct flowi fl;
 937
 938         if (_decode_session(skb, &fl, family) < 0)
 939                 return 0;
 940
 941         /* First, check used SA against their selectors. */
 942         if (skb->sp) {
 943                 int i;
 944
 945                 for (i=skb->sp->len-1; i>=0; i--) {
 946                   struct sec_decap_state *xvec = &(skb->sp->x[i]);
 947                         if (!xfrm_selector_match(&xvec->xvec->sel, &fl, family))
 948                                 return 0;
 949
 950                         /* If there is a post_input processor, try running it */
 951                         if (xvec->xvec->type->post_input &&
 952                             (xvec->xvec->type->post_input)(xvec->xvec,
 953                                                            &(xvec->decap),
 954                                                            skb) != 0)
 955                                 return 0;
 956                 }
 957         }
 958
 959         pol = NULL;
 960         if (sk && sk->sk_policy[dir])
 961                 pol = xfrm_sk_policy_lookup(sk, dir, &fl);
 962
 963         if (!pol)
 964                 pol = flow_cache_lookup(&fl, family,
 965                                         policy_to_flow_dir(dir),
 966                                         xfrm_policy_lookup);
 967
 968         if (!pol)
 969                 return !skb->sp || !secpath_has_tunnel(skb->sp, 0);
 970
 971         pol->curlft.use_time = (unsigned long)xtime.tv_sec;
 972
 973         if (pol->action == XFRM_POLICY_ALLOW) {
 974                 struct sec_path *sp;
 975                 static struct sec_path dummy;
 976                 int i, k;
 977
 978                 if ((sp = skb->sp) == NULL)
 979                         sp = &dummy;
 980
 981                 /* For each tunnel xfrm, find the first matching tmpl.
 982                  * For each tmpl before that, find corresponding xfrm.
 983                  * Order is _important_. Later we will implement
 984                  * some barriers, but at the moment barriers
 985                  * are implied between each two transformations.
 986                  */
 987                 for (i = pol->xfrm_nr-1, k = 0; i >= 0; i--) {
 988                         k = xfrm_policy_ok(pol->xfrm_vec+i, sp, k, family);
 989                         if (k < 0)
 990                                 goto reject;
 991                 }
 992
 993                 if (secpath_has_tunnel(sp, k))
 994                         goto reject;
 995
 996                 xfrm_pol_put(pol);
 997                 return 1;
 998         }
 999
1000 reject:
1001         xfrm_pol_put(pol);
1002         return 0;
1003 }
1004 EXPORT_SYMBOL(__xfrm_policy_check);
1005
1006 int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
1007 {
1008         struct flowi fl;
1009
1010         if (_decode_session(skb, &fl, family) < 0)
1011                 return 0;
1012
1013         return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
1014 }
1015 EXPORT_SYMBOL(__xfrm_route_forward);
1016
1017 /* Optimize later using cookies and generation ids. */
1018
1019 static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
1020 {
1021         if (!stale_bundle(dst))
1022                 return dst;
1023
1024         return NULL;
1025 }
1026
1027 static int stale_bundle(struct dst_entry *dst)
1028 {
1029         return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC);
1030 }
1031
1032 void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
1033 {
1034         while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
1035                 dst->dev = &loopback_dev;
1036                 dev_hold(&loopback_dev);
1037                 dev_put(dev);
1038         }
1039 }
1040 EXPORT_SYMBOL(xfrm_dst_ifdown);
1041
1042 static void xfrm_link_failure(struct sk_buff *skb)
1043 {
1044         /* Impossible. Such dst must be popped before reaches point of failure. */
1045         return;
1046 }
1047
1048 static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
1049 {
1050         if (dst) {
1051                 if (dst->obsolete) {
1052                         dst_release(dst);
1053                         dst = NULL;
1054                 }
1055         }
1056         return dst;
1057 }
1058
1059 static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
1060 {
1061         int i;
1062         struct xfrm_policy *pol;
1063         struct dst_entry *dst, **dstp, *gc_list = NULL;
1064
1065         read_lock_bh(&xfrm_policy_lock);
1066         for (i=0; i<2*XFRM_POLICY_MAX; i++) {
1067                 for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
1068                         write_lock(&pol->lock);
1069                         dstp = &pol->bundles;
1070                         while ((dst=*dstp) != NULL) {
1071                                 if (func(dst)) {
1072                                         *dstp = dst->next;
1073                                         dst->next = gc_list;
1074                                         gc_list = dst;
1075                                 } else {
1076                                         dstp = &dst->next;
1077                                 }
1078                         }
1079                         write_unlock(&pol->lock);
1080                 }
1081         }
1082         read_unlock_bh(&xfrm_policy_lock);
1083
1084         while (gc_list) {
1085                 dst = gc_list;
1086                 gc_list = dst->next;
1087                 dst_free(dst);
1088         }
1089 }
1090
1091 static int unused_bundle(struct dst_entry *dst)
1092 {
1093         return !atomic_read(&dst->__refcnt);
1094 }
1095
1096 static void __xfrm_garbage_collect(void)
1097 {
1098         xfrm_prune_bundles(unused_bundle);
1099 }
1100
1101 int xfrm_flush_bundles(void)
1102 {
1103         xfrm_prune_bundles(stale_bundle);
1104         return 0;
1105 }
1106
1107 void xfrm_init_pmtu(struct dst_entry *dst)
1108 {
1109         do {
1110                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1111                 u32 pmtu, route_mtu_cached;
1112
1113                 pmtu = dst_mtu(dst->child);
1114                 xdst->child_mtu_cached = pmtu;
1115
1116                 pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
1117
1118                 route_mtu_cached = dst_mtu(xdst->route);
1119                 xdst->route_mtu_cached = route_mtu_cached;
1120
1121                 if (pmtu > route_mtu_cached)
1122                         pmtu = route_mtu_cached;
1123
1124                 dst->metrics[RTAX_MTU-1] = pmtu;
1125         } while ((dst = dst->next));
1126 }
1127
1128 EXPORT_SYMBOL(xfrm_init_pmtu);
1129
1130 /* Check that the bundle accepts the flow and its components are
1131  * still valid.
1132  */
1133
1134 int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family)
1135 {
1136         struct dst_entry *dst = &first->u.dst;
1137         struct xfrm_dst *last;
1138         u32 mtu;
1139
1140         if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
1141             (dst->dev && !netif_running(dst->dev)))
1142                 return 0;
1143
1144         last = NULL;
1145
1146         do {
1147                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1148
1149                 if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
1150                         return 0;
1151                 if (dst->xfrm->km.state != XFRM_STATE_VALID)
1152                         return 0;
1153
1154                 mtu = dst_mtu(dst->child);
1155                 if (xdst->child_mtu_cached != mtu) {
1156                         last = xdst;
1157                         xdst->child_mtu_cached = mtu;
1158                 }
1159
1160                 if (!dst_check(xdst->route, xdst->route_cookie))
1161                         return 0;
1162                 mtu = dst_mtu(xdst->route);
1163                 if (xdst->route_mtu_cached != mtu) {
1164                         last = xdst;
1165                         xdst->route_mtu_cached = mtu;
1166                 }
1167
1168                 dst = dst->child;
1169         } while (dst->xfrm);
1170
1171         if (likely(!last))
1172                 return 1;
1173
1174         mtu = last->child_mtu_cached;
1175         for (;;) {
1176                 dst = &last->u.dst;
1177
1178                 mtu = xfrm_state_mtu(dst->xfrm, mtu);
1179                 if (mtu > last->route_mtu_cached)
1180                         mtu = last->route_mtu_cached;
1181                 dst->metrics[RTAX_MTU-1] = mtu;
1182
1183                 if (last == first)
1184                         break;
1185
1186                 last = last->u.next;
1187                 last->child_mtu_cached = mtu;
1188         }
1189
1190         return 1;
1191 }
1192
1193 EXPORT_SYMBOL(xfrm_bundle_ok);
1194
1195 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
1196 {
1197         int err = 0;
1198         if (unlikely(afinfo == NULL))
1199                 return -EINVAL;
1200         if (unlikely(afinfo->family >= NPROTO))
1201                 return -EAFNOSUPPORT;
1202         write_lock(&xfrm_policy_afinfo_lock);
1203         if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
1204                 err = -ENOBUFS;
1205         else {
1206                 struct dst_ops *dst_ops = afinfo->dst_ops;
1207                 if (likely(dst_ops->kmem_cachep == NULL))
1208                         dst_ops->kmem_cachep = xfrm_dst_cache;
1209                 if (likely(dst_ops->check == NULL))
1210                         dst_ops->check = xfrm_dst_check;
1211                 if (likely(dst_ops->negative_advice == NULL))
1212                         dst_ops->negative_advice = xfrm_negative_advice;
1213                 if (likely(dst_ops->link_failure == NULL))
1214                         dst_ops->link_failure = xfrm_link_failure;
1215                 if (likely(afinfo->garbage_collect == NULL))
1216                         afinfo->garbage_collect = __xfrm_garbage_collect;
1217                 xfrm_policy_afinfo[afinfo->family] = afinfo;
1218         }
1219         write_unlock(&xfrm_policy_afinfo_lock);
1220         return err;
1221 }
1222 EXPORT_SYMBOL(xfrm_policy_register_afinfo);
1223
1224 int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
1225 {
1226         int err = 0;
1227         if (unlikely(afinfo == NULL))
1228                 return -EINVAL;
1229         if (unlikely(afinfo->family >= NPROTO))
1230                 return -EAFNOSUPPORT;
1231         write_lock(&xfrm_policy_afinfo_lock);
1232         if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
1233                 if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
1234                         err = -EINVAL;
1235                 else {
1236                         struct dst_ops *dst_ops = afinfo->dst_ops;
1237                         xfrm_policy_afinfo[afinfo->family] = NULL;
1238                         dst_ops->kmem_cachep = NULL;
1239                         dst_ops->check = NULL;
1240                         dst_ops->negative_advice = NULL;
1241                         dst_ops->link_failure = NULL;
1242                         afinfo->garbage_collect = NULL;
1243                 }
1244         }
1245         write_unlock(&xfrm_policy_afinfo_lock);
1246         return err;
1247 }
1248 EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
1249
1250 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
1251 {
1252         struct xfrm_policy_afinfo *afinfo;
1253         if (unlikely(family >= NPROTO))
1254                 return NULL;
1255         read_lock(&xfrm_policy_afinfo_lock);
1256         afinfo = xfrm_policy_afinfo[family];
1257         if (likely(afinfo != NULL))
1258                 read_lock(&afinfo->lock);
1259         read_unlock(&xfrm_policy_afinfo_lock);
1260         return afinfo;
1261 }
1262
1263 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
1264 {
1265         if (unlikely(afinfo == NULL))
1266                 return;
1267         read_unlock(&afinfo->lock);
1268 }
1269
1270 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
1271 {
1272         switch (event) {
1273         case NETDEV_DOWN:
1274                 xfrm_flush_bundles();
1275         }
1276         return NOTIFY_DONE;
1277 }
1278
1279 static struct notifier_block xfrm_dev_notifier = {
1280         xfrm_dev_event,
1281         NULL,
1282         0
1283 };
1284
1285 static void __init xfrm_policy_init(void)
1286 {
1287         xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
1288                                            sizeof(struct xfrm_dst),
1289                                            0, SLAB_HWCACHE_ALIGN,
1290                                            NULL, NULL);
1291         if (!xfrm_dst_cache)
1292                 panic("XFRM: failed to allocate xfrm_dst_cache\n");
1293
1294         INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
1295         register_netdevice_notifier(&xfrm_dev_notifier);
1296 }
1297
1298 void __init xfrm_init(void)
1299 {
1300         xfrm_state_init();
1301         xfrm_policy_init();
1302         xfrm_input_init();
1303 }
1304