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         struct dst_entry *gc_list;
 350
 351         write_lock_bh(&xfrm_policy_lock);
 352         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL;) {
 353                 if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0) {
 354                         if (excl) {
 355                                 write_unlock_bh(&xfrm_policy_lock);
 356                                 return -EEXIST;
 357                         }
 358                         *p = pol->next;
 359                         delpol = pol;
 360                         if (policy->priority > pol->priority)
 361                                 continue;
 362                 } else if (policy->priority >= pol->priority) {
 363                         p = &pol->next;
 364                         continue;
 365                 }
 366                 if (!newpos)
 367                         newpos = p;
 368                 if (delpol)
 369                         break;
 370                 p = &pol->next;
 371         }
 372         if (newpos)
 373                 p = newpos;
 374         xfrm_pol_hold(policy);
 375         policy->next = *p;
 376         *p = policy;
 377         atomic_inc(&flow_cache_genid);
 378         policy->index = delpol ? delpol->index : xfrm_gen_index(dir);
 379         policy->curlft.add_time = (unsigned long)xtime.tv_sec;
 380         policy->curlft.use_time = 0;
 381         if (!mod_timer(&policy->timer, jiffies + HZ))
 382                 xfrm_pol_hold(policy);
 383         write_unlock_bh(&xfrm_policy_lock);
 384
 385         if (delpol)
 386                 xfrm_policy_kill(delpol);
 387
 388         read_lock_bh(&xfrm_policy_lock);
 389         gc_list = NULL;
 390         for (policy = policy->next; policy; policy = policy->next) {
 391                 struct dst_entry *dst;
 392
 393                 write_lock(&policy->lock);
 394                 dst = policy->bundles;
 395                 if (dst) {
 396                         struct dst_entry *tail = dst;
 397                         while (tail->next)
 398                                 tail = tail->next;
 399                         tail->next = gc_list;
 400                         gc_list = dst;
 401
 402                         policy->bundles = NULL;
 403                 }
 404                 write_unlock(&policy->lock);
 405         }
 406         read_unlock_bh(&xfrm_policy_lock);
 407
 408         while (gc_list) {
 409                 struct dst_entry *dst = gc_list;
 410
 411                 gc_list = dst->next;
 412                 dst_free(dst);
 413         }
 414
 415         return 0;
 416 }
 417 EXPORT_SYMBOL(xfrm_policy_insert);
 418
 419 struct xfrm_policy *xfrm_policy_bysel(int dir, struct xfrm_selector *sel,
 420                                       int delete)
 421 {
 422         struct xfrm_policy *pol, **p;
 423
 424         write_lock_bh(&xfrm_policy_lock);
 425         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
 426                 if (memcmp(sel, &pol->selector, sizeof(*sel)) == 0) {
 427                         xfrm_pol_hold(pol);
 428                         if (delete)
 429                                 *p = pol->next;
 430                         break;
 431                 }
 432         }
 433         write_unlock_bh(&xfrm_policy_lock);
 434
 435         if (pol && delete) {
 436                 atomic_inc(&flow_cache_genid);
 437                 xfrm_policy_kill(pol);
 438         }
 439         return pol;
 440 }
 441 EXPORT_SYMBOL(xfrm_policy_bysel);
 442
 443 struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete)
 444 {
 445         struct xfrm_policy *pol, **p;
 446
 447         write_lock_bh(&xfrm_policy_lock);
 448         for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
 449                 if (pol->index == id) {
 450                         xfrm_pol_hold(pol);
 451                         if (delete)
 452                                 *p = pol->next;
 453                         break;
 454                 }
 455         }
 456         write_unlock_bh(&xfrm_policy_lock);
 457
 458         if (pol && delete) {
 459                 atomic_inc(&flow_cache_genid);
 460                 xfrm_policy_kill(pol);
 461         }
 462         return pol;
 463 }
 464 EXPORT_SYMBOL(xfrm_policy_byid);
 465
 466 void xfrm_policy_flush(void)
 467 {
 468         struct xfrm_policy *xp;
 469         int dir;
 470
 471         write_lock_bh(&xfrm_policy_lock);
 472         for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
 473                 while ((xp = xfrm_policy_list[dir]) != NULL) {
 474                         xfrm_policy_list[dir] = xp->next;
 475                         write_unlock_bh(&xfrm_policy_lock);
 476
 477                         xfrm_policy_kill(xp);
 478
 479                         write_lock_bh(&xfrm_policy_lock);
 480                 }
 481         }
 482         atomic_inc(&flow_cache_genid);
 483         write_unlock_bh(&xfrm_policy_lock);
 484 }
 485 EXPORT_SYMBOL(xfrm_policy_flush);
 486
 487 int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*),
 488                      void *data)
 489 {
 490         struct xfrm_policy *xp;
 491         int dir;
 492         int count = 0;
 493         int error = 0;
 494
 495         read_lock_bh(&xfrm_policy_lock);
 496         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
 497                 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next)
 498                         count++;
 499         }
 500
 501         if (count == 0) {
 502                 error = -ENOENT;
 503                 goto out;
 504         }
 505
 506         for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
 507                 for (xp = xfrm_policy_list[dir]; xp; xp = xp->next) {
 508                         error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
 509                         if (error)
 510                                 goto out;
 511                 }
 512         }
 513
 514 out:
 515         read_unlock_bh(&xfrm_policy_lock);
 516         return error;
 517 }
 518 EXPORT_SYMBOL(xfrm_policy_walk);
 519
 520 /* Find policy to apply to this flow. */
 521
 522 static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
 523                                void **objp, atomic_t **obj_refp)
 524 {
 525         struct xfrm_policy *pol;
 526
 527         read_lock_bh(&xfrm_policy_lock);
 528         for (pol = xfrm_policy_list[dir]; pol; pol = pol->next) {
 529                 struct xfrm_selector *sel = &pol->selector;
 530                 int match;
 531
 532                 if (pol->family != family)
 533                         continue;
 534
 535                 match = xfrm_selector_match(sel, fl, family);
 536                 if (match) {
 537                         xfrm_pol_hold(pol);
 538                         break;
 539                 }
 540         }
 541         read_unlock_bh(&xfrm_policy_lock);
 542         if ((*objp = (void *) pol) != NULL)
 543                 *obj_refp = &pol->refcnt;
 544 }
 545
 546 static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl)
 547 {
 548         struct xfrm_policy *pol;
 549
 550         read_lock_bh(&xfrm_policy_lock);
 551         if ((pol = sk->sk_policy[dir]) != NULL) {
 552                 int match = xfrm_selector_match(&pol->selector, fl,
 553                                                 sk->sk_family);
 554                 if (match)
 555                         xfrm_pol_hold(pol);
 556                 else
 557                         pol = NULL;
 558         }
 559         read_unlock_bh(&xfrm_policy_lock);
 560         return pol;
 561 }
 562
 563 static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
 564 {
 565         pol->next = xfrm_policy_list[dir];
 566         xfrm_policy_list[dir] = pol;
 567         xfrm_pol_hold(pol);
 568 }
 569
 570 static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
 571                                                 int dir)
 572 {
 573         struct xfrm_policy **polp;
 574
 575         for (polp = &xfrm_policy_list[dir];
 576              *polp != NULL; polp = &(*polp)->next) {
 577                 if (*polp == pol) {
 578                         *polp = pol->next;
 579                         return pol;
 580                 }
 581         }
 582         return NULL;
 583 }
 584
 585 int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
 586 {
 587         write_lock_bh(&xfrm_policy_lock);
 588         pol = __xfrm_policy_unlink(pol, dir);
 589         write_unlock_bh(&xfrm_policy_lock);
 590         if (pol) {
 591                 if (dir < XFRM_POLICY_MAX)
 592                         atomic_inc(&flow_cache_genid);
 593                 xfrm_policy_kill(pol);
 594                 return 0;
 595         }
 596         return -ENOENT;
 597 }
 598
 599 int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
 600 {
 601         struct xfrm_policy *old_pol;
 602
 603         write_lock_bh(&xfrm_policy_lock);
 604         old_pol = sk->sk_policy[dir];
 605         sk->sk_policy[dir] = pol;
 606         if (pol) {
 607                 pol->curlft.add_time = (unsigned long)xtime.tv_sec;
 608                 pol->index = xfrm_gen_index(XFRM_POLICY_MAX+dir);
 609                 __xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
 610         }
 611         if (old_pol)
 612                 __xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
 613         write_unlock_bh(&xfrm_policy_lock);
 614
 615         if (old_pol) {
 616                 xfrm_policy_kill(old_pol);
 617         }
 618         return 0;
 619 }
 620
 621 static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
 622 {
 623         struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
 624
 625         if (newp) {
 626                 newp->selector = old->selector;
 627                 newp->lft = old->lft;
 628                 newp->curlft = old->curlft;
 629                 newp->action = old->action;
 630                 newp->flags = old->flags;
 631                 newp->xfrm_nr = old->xfrm_nr;
 632                 newp->index = old->index;
 633                 memcpy(newp->xfrm_vec, old->xfrm_vec,
 634                        newp->xfrm_nr*sizeof(struct xfrm_tmpl));
 635                 write_lock_bh(&xfrm_policy_lock);
 636                 __xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
 637                 write_unlock_bh(&xfrm_policy_lock);
 638                 xfrm_pol_put(newp);
 639         }
 640         return newp;
 641 }
 642
 643 int __xfrm_sk_clone_policy(struct sock *sk)
 644 {
 645         struct xfrm_policy *p0 = sk->sk_policy[0],
 646                            *p1 = sk->sk_policy[1];
 647
 648         sk->sk_policy[0] = sk->sk_policy[1] = NULL;
 649         if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
 650                 return -ENOMEM;
 651         if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
 652                 return -ENOMEM;
 653         return 0;
 654 }
 655
 656 /* Resolve list of templates for the flow, given policy. */
 657
 658 static int
 659 xfrm_tmpl_resolve(struct xfrm_policy *policy, struct flowi *fl,
 660                   struct xfrm_state **xfrm,
 661                   unsigned short family)
 662 {
 663         int nx;
 664         int i, error;
 665         xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
 666         xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
 667
 668         for (nx=0, i = 0; i < policy->xfrm_nr; i++) {
 669                 struct xfrm_state *x;
 670                 xfrm_address_t *remote = daddr;
 671                 xfrm_address_t *local  = saddr;
 672                 struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
 673
 674                 if (tmpl->mode) {
 675                         remote = &tmpl->id.daddr;
 676                         local = &tmpl->saddr;
 677                 }
 678
 679                 x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
 680
 681                 if (x && x->km.state == XFRM_STATE_VALID) {
 682                         xfrm[nx++] = x;
 683                         daddr = remote;
 684                         saddr = local;
 685                         continue;
 686                 }
 687                 if (x) {
 688                         error = (x->km.state == XFRM_STATE_ERROR ?
 689                                  -EINVAL : -EAGAIN);
 690                         xfrm_state_put(x);
 691                 }
 692
 693                 if (!tmpl->optional)
 694                         goto fail;
 695         }
 696         return nx;
 697
 698 fail:
 699         for (nx--; nx>=0; nx--)
 700                 xfrm_state_put(xfrm[nx]);
 701         return error;
 702 }
 703
 704 /* Check that the bundle accepts the flow and its components are
 705  * still valid.
 706  */
 707
 708 static struct dst_entry *
 709 xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
 710 {
 711         struct dst_entry *x;
 712         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 713         if (unlikely(afinfo == NULL))
 714                 return ERR_PTR(-EINVAL);
 715         x = afinfo->find_bundle(fl, policy);
 716         xfrm_policy_put_afinfo(afinfo);
 717         return x;
 718 }
 719
 720 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 721  * all the metrics... Shortly, bundle a bundle.
 722  */
 723
 724 static int
 725 xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 726                    struct flowi *fl, struct dst_entry **dst_p,
 727                    unsigned short family)
 728 {
 729         int err;
 730         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 731         if (unlikely(afinfo == NULL))
 732                 return -EINVAL;
 733         err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
 734         xfrm_policy_put_afinfo(afinfo);
 735         return err;
 736 }
 737
 738 static inline int policy_to_flow_dir(int dir)
 739 {
 740         if (XFRM_POLICY_IN == FLOW_DIR_IN &&
 741             XFRM_POLICY_OUT == FLOW_DIR_OUT &&
 742             XFRM_POLICY_FWD == FLOW_DIR_FWD)
 743                 return dir;
 744         switch (dir) {
 745         default:
 746         case XFRM_POLICY_IN:
 747                 return FLOW_DIR_IN;
 748         case XFRM_POLICY_OUT:
 749                 return FLOW_DIR_OUT;
 750         case XFRM_POLICY_FWD:
 751                 return FLOW_DIR_FWD;
 752         };
 753 }
 754
 755 static int stale_bundle(struct dst_entry *dst);
 756
 757 /* Main function: finds/creates a bundle for given flow.
 758  *
 759  * At the moment we eat a raw IP route. Mostly to speed up lookups
 760  * on interfaces with disabled IPsec.
 761  */
 762 int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 763                 struct sock *sk, int flags)
 764 {
 765         struct xfrm_policy *policy;
 766         struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
 767         struct dst_entry *dst, *dst_orig = *dst_p;
 768         int nx = 0;
 769         int err;
 770         u32 genid;
 771         u16 family = dst_orig->ops->family;
 772 restart:
 773         genid = atomic_read(&flow_cache_genid);
 774         policy = NULL;
 775         if (sk && sk->sk_policy[1])
 776                 policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
 777
 778         if (!policy) {
 779                 /* To accelerate a bit...  */
 780                 if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
 781                         return 0;
 782
 783                 policy = flow_cache_lookup(fl, family,
 784                                            policy_to_flow_dir(XFRM_POLICY_OUT),
 785                                            xfrm_policy_lookup);
 786         }
 787
 788         if (!policy)
 789                 return 0;
 790
 791         policy->curlft.use_time = (unsigned long)xtime.tv_sec;
 792
 793         switch (policy->action) {
 794         case XFRM_POLICY_BLOCK:
 795                 /* Prohibit the flow */
 796                 err = -EPERM;
 797                 goto error;
 798
 799         case XFRM_POLICY_ALLOW:
 800                 if (policy->xfrm_nr == 0) {
 801                         /* Flow passes not transformed. */
 802                         xfrm_pol_put(policy);
 803                         return 0;
 804                 }
 805
 806                 /* Try to find matching bundle.
 807                  *
 808                  * LATER: help from flow cache. It is optional, this
 809                  * is required only for output policy.
 810                  */
 811                 dst = xfrm_find_bundle(fl, policy, family);
 812                 if (IS_ERR(dst)) {
 813                         err = PTR_ERR(dst);
 814                         goto error;
 815                 }
 816
 817                 if (dst)
 818                         break;
 819
 820                 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
 821
 822                 if (unlikely(nx<0)) {
 823                         err = nx;
 824                         if (err == -EAGAIN && flags) {
 825                                 DECLARE_WAITQUEUE(wait, current);
 826
 827                                 add_wait_queue(&km_waitq, &wait);
 828                                 set_current_state(TASK_INTERRUPTIBLE);
 829                                 schedule();
 830                                 set_current_state(TASK_RUNNING);
 831                                 remove_wait_queue(&km_waitq, &wait);
 832
 833                                 nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
 834
 835                                 if (nx == -EAGAIN && signal_pending(current)) {
 836                                         err = -ERESTART;
 837                                         goto error;
 838                                 }
 839                                 if (nx == -EAGAIN ||
 840                                     genid != atomic_read(&flow_cache_genid)) {
 841                                         xfrm_pol_put(policy);
 842                                         goto restart;
 843                                 }
 844                                 err = nx;
 845                         }
 846                         if (err < 0)
 847                                 goto error;
 848                 }
 849                 if (nx == 0) {
 850                         /* Flow passes not transformed. */
 851                         xfrm_pol_put(policy);
 852                         return 0;
 853                 }
 854
 855                 dst = dst_orig;
 856                 err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
 857
 858                 if (unlikely(err)) {
 859                         int i;
 860                         for (i=0; i<nx; i++)
 861                                 xfrm_state_put(xfrm[i]);
 862                         goto error;
 863                 }
 864
 865                 write_lock_bh(&policy->lock);
 866                 if (unlikely(policy->dead || stale_bundle(dst))) {
 867                         /* Wow! While we worked on resolving, this
 868                          * policy has gone. Retry. It is not paranoia,
 869                          * we just cannot enlist new bundle to dead object.
 870                          * We can't enlist stable bundles either.
 871                          */
 872                         write_unlock_bh(&policy->lock);
 873
 874                         xfrm_pol_put(policy);
 875                         if (dst)
 876                                 dst_free(dst);
 877                         goto restart;
 878                 }
 879                 dst->next = policy->bundles;
 880                 policy->bundles = dst;
 881                 dst_hold(dst);
 882                 write_unlock_bh(&policy->lock);
 883         }
 884         *dst_p = dst;
 885         dst_release(dst_orig);
 886         xfrm_pol_put(policy);
 887         return 0;
 888
 889 error:
 890         dst_release(dst_orig);
 891         xfrm_pol_put(policy);
 892         *dst_p = NULL;
 893         return err;
 894 }
 895 EXPORT_SYMBOL(xfrm_lookup);
 896
 897 /* When skb is transformed back to its "native" form, we have to
 898  * check policy restrictions. At the moment we make this in maximally
 899  * stupid way. Shame on me. :-) Of course, connected sockets must
 900  * have policy cached at them.
 901  */
 902
 903 static inline int
 904 xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x,
 905               unsigned short family)
 906 {
 907         if (xfrm_state_kern(x))
 908                 return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, family);
 909         return  x->id.proto == tmpl->id.proto &&
 910                 (x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
 911                 (x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
 912                 x->props.mode == tmpl->mode &&
 913                 (tmpl->aalgos & (1<<x->props.aalgo)) &&
 914                 !(x->props.mode && xfrm_state_addr_cmp(tmpl, x, family));
 915 }
 916
 917 static inline int
 918 xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
 919                unsigned short family)
 920 {
 921         int idx = start;
 922
 923         if (tmpl->optional) {
 924                 if (!tmpl->mode)
 925                         return start;
 926         } else
 927                 start = -1;
 928         for (; idx < sp->len; idx++) {
 929                 if (xfrm_state_ok(tmpl, sp->x[idx].xvec, family))
 930                         return ++idx;
 931                 if (sp->x[idx].xvec->props.mode)
 932                         break;
 933         }
 934         return start;
 935 }
 936
 937 static int
 938 _decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
 939 {
 940         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 941
 942         if (unlikely(afinfo == NULL))
 943                 return -EAFNOSUPPORT;
 944
 945         afinfo->decode_session(skb, fl);
 946         xfrm_policy_put_afinfo(afinfo);
 947         return 0;
 948 }
 949
 950 static inline int secpath_has_tunnel(struct sec_path *sp, int k)
 951 {
 952         for (; k < sp->len; k++) {
 953                 if (sp->x[k].xvec->props.mode)
 954                         return 1;
 955         }
 956
 957         return 0;
 958 }
 959
 960 int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
 961                         unsigned short family)
 962 {
 963         struct xfrm_policy *pol;
 964         struct flowi fl;
 965
 966         if (_decode_session(skb, &fl, family) < 0)
 967                 return 0;
 968
 969         /* First, check used SA against their selectors. */
 970         if (skb->sp) {
 971                 int i;
 972
 973                 for (i=skb->sp->len-1; i>=0; i--) {
 974                   struct sec_decap_state *xvec = &(skb->sp->x[i]);
 975                         if (!xfrm_selector_match(&xvec->xvec->sel, &fl, family))
 976                                 return 0;
 977
 978                         /* If there is a post_input processor, try running it */
 979                         if (xvec->xvec->type->post_input &&
 980                             (xvec->xvec->type->post_input)(xvec->xvec,
 981                                                            &(xvec->decap),
 982                                                            skb) != 0)
 983                                 return 0;
 984                 }
 985         }
 986
 987         pol = NULL;
 988         if (sk && sk->sk_policy[dir])
 989                 pol = xfrm_sk_policy_lookup(sk, dir, &fl);
 990
 991         if (!pol)
 992                 pol = flow_cache_lookup(&fl, family,
 993                                         policy_to_flow_dir(dir),
 994                                         xfrm_policy_lookup);
 995
 996         if (!pol)
 997                 return !skb->sp || !secpath_has_tunnel(skb->sp, 0);
 998
 999         pol->curlft.use_time = (unsigned long)xtime.tv_sec;
1000
1001         if (pol->action == XFRM_POLICY_ALLOW) {
1002                 struct sec_path *sp;
1003                 static struct sec_path dummy;
1004                 int i, k;
1005
1006                 if ((sp = skb->sp) == NULL)
1007                         sp = &dummy;
1008
1009                 /* For each tunnel xfrm, find the first matching tmpl.
1010                  * For each tmpl before that, find corresponding xfrm.
1011                  * Order is _important_. Later we will implement
1012                  * some barriers, but at the moment barriers
1013                  * are implied between each two transformations.
1014                  */
1015                 for (i = pol->xfrm_nr-1, k = 0; i >= 0; i--) {
1016                         k = xfrm_policy_ok(pol->xfrm_vec+i, sp, k, family);
1017                         if (k < 0)
1018                                 goto reject;
1019                 }
1020
1021                 if (secpath_has_tunnel(sp, k))
1022                         goto reject;
1023
1024                 xfrm_pol_put(pol);
1025                 return 1;
1026         }
1027
1028 reject:
1029         xfrm_pol_put(pol);
1030         return 0;
1031 }
1032 EXPORT_SYMBOL(__xfrm_policy_check);
1033
1034 int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
1035 {
1036         struct flowi fl;
1037
1038         if (_decode_session(skb, &fl, family) < 0)
1039                 return 0;
1040
1041         return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
1042 }
1043 EXPORT_SYMBOL(__xfrm_route_forward);
1044
1045 static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
1046 {
1047         /* If it is marked obsolete, which is how we even get here,
1048          * then we have purged it from the policy bundle list and we
1049          * did that for a good reason.
1050          */
1051         return NULL;
1052 }
1053
1054 static int stale_bundle(struct dst_entry *dst)
1055 {
1056         return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC);
1057 }
1058
1059 void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
1060 {
1061         while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
1062                 dst->dev = &loopback_dev;
1063                 dev_hold(&loopback_dev);
1064                 dev_put(dev);
1065         }
1066 }
1067 EXPORT_SYMBOL(xfrm_dst_ifdown);
1068
1069 static void xfrm_link_failure(struct sk_buff *skb)
1070 {
1071         /* Impossible. Such dst must be popped before reaches point of failure. */
1072         return;
1073 }
1074
1075 static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
1076 {
1077         if (dst) {
1078                 if (dst->obsolete) {
1079                         dst_release(dst);
1080                         dst = NULL;
1081                 }
1082         }
1083         return dst;
1084 }
1085
1086 static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
1087 {
1088         int i;
1089         struct xfrm_policy *pol;
1090         struct dst_entry *dst, **dstp, *gc_list = NULL;
1091
1092         read_lock_bh(&xfrm_policy_lock);
1093         for (i=0; i<2*XFRM_POLICY_MAX; i++) {
1094                 for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
1095                         write_lock(&pol->lock);
1096                         dstp = &pol->bundles;
1097                         while ((dst=*dstp) != NULL) {
1098                                 if (func(dst)) {
1099                                         *dstp = dst->next;
1100                                         dst->next = gc_list;
1101                                         gc_list = dst;
1102                                 } else {
1103                                         dstp = &dst->next;
1104                                 }
1105                         }
1106                         write_unlock(&pol->lock);
1107                 }
1108         }
1109         read_unlock_bh(&xfrm_policy_lock);
1110
1111         while (gc_list) {
1112                 dst = gc_list;
1113                 gc_list = dst->next;
1114                 dst_free(dst);
1115         }
1116 }
1117
1118 static int unused_bundle(struct dst_entry *dst)
1119 {
1120         return !atomic_read(&dst->__refcnt);
1121 }
1122
1123 static void __xfrm_garbage_collect(void)
1124 {
1125         xfrm_prune_bundles(unused_bundle);
1126 }
1127
1128 int xfrm_flush_bundles(void)
1129 {
1130         xfrm_prune_bundles(stale_bundle);
1131         return 0;
1132 }
1133
1134 static int always_true(struct dst_entry *dst)
1135 {
1136         return 1;
1137 }
1138
1139 void xfrm_flush_all_bundles(void)
1140 {
1141         xfrm_prune_bundles(always_true);
1142 }
1143
1144 void xfrm_init_pmtu(struct dst_entry *dst)
1145 {
1146         do {
1147                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1148                 u32 pmtu, route_mtu_cached;
1149
1150                 pmtu = dst_mtu(dst->child);
1151                 xdst->child_mtu_cached = pmtu;
1152
1153                 pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
1154
1155                 route_mtu_cached = dst_mtu(xdst->route);
1156                 xdst->route_mtu_cached = route_mtu_cached;
1157
1158                 if (pmtu > route_mtu_cached)
1159                         pmtu = route_mtu_cached;
1160
1161                 dst->metrics[RTAX_MTU-1] = pmtu;
1162         } while ((dst = dst->next));
1163 }
1164
1165 EXPORT_SYMBOL(xfrm_init_pmtu);
1166
1167 /* Check that the bundle accepts the flow and its components are
1168  * still valid.
1169  */
1170
1171 int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family)
1172 {
1173         struct dst_entry *dst = &first->u.dst;
1174         struct xfrm_dst *last;
1175         u32 mtu;
1176
1177         if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
1178             (dst->dev && !netif_running(dst->dev)))
1179                 return 0;
1180
1181         last = NULL;
1182
1183         do {
1184                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
1185
1186                 if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
1187                         return 0;
1188                 if (dst->xfrm->km.state != XFRM_STATE_VALID)
1189                         return 0;
1190
1191                 mtu = dst_mtu(dst->child);
1192                 if (xdst->child_mtu_cached != mtu) {
1193                         last = xdst;
1194                         xdst->child_mtu_cached = mtu;
1195                 }
1196
1197                 if (!dst_check(xdst->route, xdst->route_cookie))
1198                         return 0;
1199                 mtu = dst_mtu(xdst->route);
1200                 if (xdst->route_mtu_cached != mtu) {
1201                         last = xdst;
1202                         xdst->route_mtu_cached = mtu;
1203                 }
1204
1205                 dst = dst->child;
1206         } while (dst->xfrm);
1207
1208         if (likely(!last))
1209                 return 1;
1210
1211         mtu = last->child_mtu_cached;
1212         for (;;) {
1213                 dst = &last->u.dst;
1214
1215                 mtu = xfrm_state_mtu(dst->xfrm, mtu);
1216                 if (mtu > last->route_mtu_cached)
1217                         mtu = last->route_mtu_cached;
1218                 dst->metrics[RTAX_MTU-1] = mtu;
1219
1220                 if (last == first)
1221                         break;
1222
1223                 last = last->u.next;
1224                 last->child_mtu_cached = mtu;
1225         }
1226
1227         return 1;
1228 }
1229
1230 EXPORT_SYMBOL(xfrm_bundle_ok);
1231
1232 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
1233 {
1234         int err = 0;
1235         if (unlikely(afinfo == NULL))
1236                 return -EINVAL;
1237         if (unlikely(afinfo->family >= NPROTO))
1238                 return -EAFNOSUPPORT;
1239         write_lock(&xfrm_policy_afinfo_lock);
1240         if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
1241                 err = -ENOBUFS;
1242         else {
1243                 struct dst_ops *dst_ops = afinfo->dst_ops;
1244                 if (likely(dst_ops->kmem_cachep == NULL))
1245                         dst_ops->kmem_cachep = xfrm_dst_cache;
1246                 if (likely(dst_ops->check == NULL))
1247                         dst_ops->check = xfrm_dst_check;
1248                 if (likely(dst_ops->negative_advice == NULL))
1249                         dst_ops->negative_advice = xfrm_negative_advice;
1250                 if (likely(dst_ops->link_failure == NULL))
1251                         dst_ops->link_failure = xfrm_link_failure;
1252                 if (likely(afinfo->garbage_collect == NULL))
1253                         afinfo->garbage_collect = __xfrm_garbage_collect;
1254                 xfrm_policy_afinfo[afinfo->family] = afinfo;
1255         }
1256         write_unlock(&xfrm_policy_afinfo_lock);
1257         return err;
1258 }
1259 EXPORT_SYMBOL(xfrm_policy_register_afinfo);
1260
1261 int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
1262 {
1263         int err = 0;
1264         if (unlikely(afinfo == NULL))
1265                 return -EINVAL;
1266         if (unlikely(afinfo->family >= NPROTO))
1267                 return -EAFNOSUPPORT;
1268         write_lock(&xfrm_policy_afinfo_lock);
1269         if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
1270                 if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
1271                         err = -EINVAL;
1272                 else {
1273                         struct dst_ops *dst_ops = afinfo->dst_ops;
1274                         xfrm_policy_afinfo[afinfo->family] = NULL;
1275                         dst_ops->kmem_cachep = NULL;
1276                         dst_ops->check = NULL;
1277                         dst_ops->negative_advice = NULL;
1278                         dst_ops->link_failure = NULL;
1279                         afinfo->garbage_collect = NULL;
1280                 }
1281         }
1282         write_unlock(&xfrm_policy_afinfo_lock);
1283         return err;
1284 }
1285 EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
1286
1287 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
1288 {
1289         struct xfrm_policy_afinfo *afinfo;
1290         if (unlikely(family >= NPROTO))
1291                 return NULL;
1292         read_lock(&xfrm_policy_afinfo_lock);
1293         afinfo = xfrm_policy_afinfo[family];
1294         if (likely(afinfo != NULL))
1295                 read_lock(&afinfo->lock);
1296         read_unlock(&xfrm_policy_afinfo_lock);
1297         return afinfo;
1298 }
1299
1300 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
1301 {
1302         if (unlikely(afinfo == NULL))
1303                 return;
1304         read_unlock(&afinfo->lock);
1305 }
1306
1307 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
1308 {
1309         switch (event) {
1310         case NETDEV_DOWN:
1311                 xfrm_flush_bundles();
1312         }
1313         return NOTIFY_DONE;
1314 }
1315
1316 static struct notifier_block xfrm_dev_notifier = {
1317         xfrm_dev_event,
1318         NULL,
1319         0
1320 };
1321
1322 static void __init xfrm_policy_init(void)
1323 {
1324         xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
1325                                            sizeof(struct xfrm_dst),
1326                                            0, SLAB_HWCACHE_ALIGN,
1327                                            NULL, NULL);
1328         if (!xfrm_dst_cache)
1329                 panic("XFRM: failed to allocate xfrm_dst_cache\n");
1330
1331         INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
1332         register_netdevice_notifier(&xfrm_dev_notifier);
1333 }
1334
1335 void __init xfrm_init(void)
1336 {
1337         xfrm_state_init();
1338         xfrm_policy_init();
1339         xfrm_input_init();
1340 }
1341