sys/net/pfil.c

   1 /*      $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $  */
   2
   3 /*-
   4  * SPDX-License-Identifier: BSD-3-Clause
   5  *
   6  * Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.org>
   7  * Copyright (c) 1996 Matthew R. Green
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/conf.h>
  36 #include <sys/kernel.h>
  37 #include <sys/epoch.h>
  38 #include <sys/errno.h>
  39 #include <sys/lock.h>
  40 #include <sys/malloc.h>
  41 #include <sys/socket.h>
  42 #include <sys/socketvar.h>
  43 #include <sys/systm.h>
  44 #include <sys/lock.h>
  45 #include <sys/mutex.h>
  46 #include <sys/proc.h>
  47 #include <sys/queue.h>
  48 #include <sys/ucred.h>
  49 #include <sys/jail.h>
  50
  51 #include <net/if.h>
  52 #include <net/if_var.h>
  53 #include <net/pfil.h>
  54
  55 static MALLOC_DEFINE(M_PFIL, "pfil", "pfil(9) packet filter hooks");
  56
  57 static int pfil_ioctl(struct cdev *, u_long, caddr_t, int, struct thread *);
  58 static struct cdevsw pfil_cdevsw = {
  59         .d_ioctl =      pfil_ioctl,
  60         .d_name =       PFILDEV,
  61         .d_version =    D_VERSION,
  62 };
  63 static struct cdev *pfil_dev;
  64
  65 static struct mtx pfil_lock;
  66 MTX_SYSINIT(pfil_mtxinit, &pfil_lock, "pfil(9) lock", MTX_DEF);
  67 #define PFIL_LOCK()     mtx_lock(&pfil_lock)
  68 #define PFIL_UNLOCK()   mtx_unlock(&pfil_lock)
  69 #define PFIL_LOCK_ASSERT()      mtx_assert(&pfil_lock, MA_OWNED)
  70
  71 struct pfil_hook {
  72         pfil_mbuf_chk_t  hook_mbuf_chk;
  73         pfil_mem_chk_t   hook_mem_chk;
  74         void            *hook_ruleset;
  75         int              hook_flags;
  76         int              hook_links;
  77         enum pfil_types  hook_type;
  78         const char      *hook_modname;
  79         const char      *hook_rulname;
  80         LIST_ENTRY(pfil_hook) hook_list;
  81 };
  82
  83 struct pfil_link {
  84         CK_STAILQ_ENTRY(pfil_link) link_chain;
  85         pfil_mbuf_chk_t          link_mbuf_chk;
  86         pfil_mem_chk_t           link_mem_chk;
  87         void                    *link_ruleset;
  88         int                      link_flags;
  89         struct pfil_hook        *link_hook;
  90         struct epoch_context     link_epoch_ctx;
  91 };
  92
  93 typedef CK_STAILQ_HEAD(pfil_chain, pfil_link)   pfil_chain_t;
  94 struct pfil_head {
  95         int              head_nhooksin;
  96         int              head_nhooksout;
  97         pfil_chain_t     head_in;
  98         pfil_chain_t     head_out;
  99         int              head_flags;
 100         enum pfil_types  head_type;
 101         LIST_ENTRY(pfil_head) head_list;
 102         const char      *head_name;
 103 };
 104
 105 LIST_HEAD(pfilheadhead, pfil_head);
 106 VNET_DEFINE_STATIC(struct pfilheadhead, pfil_head_list) =
 107     LIST_HEAD_INITIALIZER(pfil_head_list);
 108 #define V_pfil_head_list        VNET(pfil_head_list)
 109
 110 LIST_HEAD(pfilhookhead, pfil_hook);
 111 VNET_DEFINE_STATIC(struct pfilhookhead, pfil_hook_list) =
 112     LIST_HEAD_INITIALIZER(pfil_hook_list);
 113 #define V_pfil_hook_list        VNET(pfil_hook_list)
 114
 115 static struct pfil_link *pfil_link_remove(pfil_chain_t *, pfil_hook_t );
 116 static void pfil_link_free(epoch_context_t);
 117
 118 /*
 119  * To couple a filtering point that provides memory pointer with a filter that
 120  * works on mbufs only.
 121  */
 122 static __noinline int
 123 pfil_fake_mbuf(pfil_mbuf_chk_t func, void *mem, u_int len, struct ifnet *ifp,
 124     int flags, void *ruleset, struct mbuf **mp)
 125 {
 126         struct mbuf m;
 127         pfil_return_t rv;
 128
 129         (void)m_init(&m, M_NOWAIT, MT_DATA, M_NOFREE | M_PKTHDR);
 130         m_extadd(&m, mem, len, NULL, NULL, NULL, 0, EXT_RXRING);
 131         m.m_len = m.m_pkthdr.len = len;
 132         *mp = &m;
 133
 134         rv = func(mp, ifp, flags, ruleset, NULL);
 135         if (rv == PFIL_PASS && *mp != &m) {
 136                 /*
 137                  * Firewalls that need pfil_fake_mbuf() most likely don't
 138                  * know they need return PFIL_REALLOCED.
 139                  */
 140                 rv = PFIL_REALLOCED;
 141         }
 142
 143         return (rv);
 144 }
 145
 146 static __always_inline int
 147 pfil_mem_common(pfil_chain_t *pch, void *mem, u_int len, int flags,
 148     struct ifnet *ifp, struct mbuf **m)
 149 {
 150         struct pfil_link *link;
 151         pfil_return_t rv;
 152         bool realloc = false;
 153
 154         NET_EPOCH_ASSERT();
 155         KASSERT(flags == PFIL_IN || flags == PFIL_OUT,
 156             ("%s: unsupported flags %d", __func__, flags));
 157
 158         rv = PFIL_PASS;
 159         CK_STAILQ_FOREACH(link, pch, link_chain) {
 160                 if (__predict_true(link->link_mem_chk != NULL && !realloc))
 161                         rv = link->link_mem_chk(mem, len, flags, ifp,
 162                             link->link_ruleset, m);
 163                 else if (!realloc)
 164                         rv = pfil_fake_mbuf(link->link_mbuf_chk, mem, len, ifp,
 165                             flags, link->link_ruleset, m);
 166                 else
 167                         rv = link->link_mbuf_chk(m, ifp, flags,
 168                             link->link_ruleset, NULL);
 169
 170                 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
 171                         break;
 172                 else if (rv == PFIL_REALLOCED)
 173                         realloc = true;
 174         }
 175         if (realloc && rv == PFIL_PASS)
 176                 rv = PFIL_REALLOCED;
 177         return (rv);
 178 }
 179
 180 int
 181 pfil_mem_in(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
 182     struct mbuf **m)
 183 {
 184
 185         return (pfil_mem_common(&head->head_in, mem, len, PFIL_IN, ifp, m));
 186 }
 187
 188 int
 189 pfil_mem_out(struct pfil_head *head, void *mem, u_int len, struct ifnet *ifp,
 190     struct mbuf **m)
 191 {
 192
 193         return (pfil_mem_common(&head->head_out, mem, len, PFIL_OUT, ifp, m));
 194 }
 195
 196 static __always_inline int
 197 pfil_mbuf_common(pfil_chain_t *pch, struct mbuf **m, struct ifnet *ifp,
 198     int flags, struct inpcb *inp)
 199 {
 200         struct pfil_link *link;
 201         pfil_return_t rv;
 202
 203         NET_EPOCH_ASSERT();
 204         KASSERT((flags & ~(PFIL_IN|PFIL_OUT|PFIL_FWD)) == 0,
 205             ("%s: unsupported flags %#x", __func__, flags));
 206         KASSERT((flags & ~PFIL_FWD) == PFIL_IN ||
 207             (flags & ~PFIL_FWD) == PFIL_OUT,
 208             ("%s: conflicting directions %#x", __func__, flags));
 209
 210         rv = PFIL_PASS;
 211         CK_STAILQ_FOREACH(link, pch, link_chain) {
 212                 rv = link->link_mbuf_chk(m, ifp, flags, link->link_ruleset,
 213                     inp);
 214                 if (rv == PFIL_DROPPED || rv == PFIL_CONSUMED)
 215                         break;
 216         }
 217         return (rv);
 218 }
 219
 220 int
 221 pfil_mbuf_in(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
 222    struct inpcb *inp)
 223 {
 224
 225         return (pfil_mbuf_common(&head->head_in, m, ifp, PFIL_IN, inp));
 226 }
 227
 228 int
 229 pfil_mbuf_out(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
 230     struct inpcb *inp)
 231 {
 232
 233         return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT, inp));
 234 }
 235
 236 int
 237 pfil_mbuf_fwd(struct pfil_head *head, struct mbuf **m, struct ifnet *ifp,
 238     struct inpcb *inp)
 239 {
 240
 241         return (pfil_mbuf_common(&head->head_out, m, ifp, PFIL_OUT | PFIL_FWD, inp));
 242 }
 243
 244 /*
 245  * pfil_head_register() registers a pfil_head with the packet filter hook
 246  * mechanism.
 247  */
 248 pfil_head_t
 249 pfil_head_register(struct pfil_head_args *pa)
 250 {
 251         struct pfil_head *head, *list;
 252
 253         MPASS(pa->pa_version == PFIL_VERSION);
 254
 255         head = malloc(sizeof(struct pfil_head), M_PFIL, M_WAITOK);
 256
 257         head->head_nhooksin = head->head_nhooksout = 0;
 258         head->head_flags = pa->pa_flags;
 259         head->head_type = pa->pa_type;
 260         head->head_name = pa->pa_headname;
 261         CK_STAILQ_INIT(&head->head_in);
 262         CK_STAILQ_INIT(&head->head_out);
 263
 264         PFIL_LOCK();
 265         LIST_FOREACH(list, &V_pfil_head_list, head_list)
 266                 if (strcmp(pa->pa_headname, list->head_name) == 0) {
 267                         printf("pfil: duplicate head \"%s\"\n",
 268                             pa->pa_headname);
 269                 }
 270         LIST_INSERT_HEAD(&V_pfil_head_list, head, head_list);
 271         PFIL_UNLOCK();
 272
 273         return (head);
 274 }
 275
 276 /*
 277  * pfil_head_unregister() removes a pfil_head from the packet filter hook
 278  * mechanism.  The producer of the hook promises that all outstanding
 279  * invocations of the hook have completed before it unregisters the hook.
 280  */
 281 void
 282 pfil_head_unregister(pfil_head_t ph)
 283 {
 284         struct pfil_link *link, *next;
 285
 286         PFIL_LOCK();
 287         LIST_REMOVE(ph, head_list);
 288
 289         CK_STAILQ_FOREACH_SAFE(link, &ph->head_in, link_chain, next) {
 290                 link->link_hook->hook_links--;
 291                 free(link, M_PFIL);
 292         }
 293         CK_STAILQ_FOREACH_SAFE(link, &ph->head_out, link_chain, next) {
 294                 link->link_hook->hook_links--;
 295                 free(link, M_PFIL);
 296         }
 297         PFIL_UNLOCK();
 298         free(ph, M_PFIL);
 299 }
 300
 301 pfil_hook_t
 302 pfil_add_hook(struct pfil_hook_args *pa)
 303 {
 304         struct pfil_hook *hook, *list;
 305
 306         MPASS(pa->pa_version == PFIL_VERSION);
 307
 308         hook = malloc(sizeof(struct pfil_hook), M_PFIL, M_WAITOK | M_ZERO);
 309         hook->hook_mbuf_chk = pa->pa_mbuf_chk;
 310         hook->hook_mem_chk = pa->pa_mem_chk;
 311         hook->hook_ruleset = pa->pa_ruleset;
 312         hook->hook_flags = pa->pa_flags;
 313         hook->hook_type = pa->pa_type;
 314         hook->hook_modname = pa->pa_modname;
 315         hook->hook_rulname = pa->pa_rulname;
 316
 317         PFIL_LOCK();
 318         LIST_FOREACH(list, &V_pfil_hook_list, hook_list)
 319                 if (strcmp(pa->pa_modname, list->hook_modname) == 0 &&
 320                     strcmp(pa->pa_rulname, list->hook_rulname) == 0) {
 321                         printf("pfil: duplicate hook \"%s:%s\"\n",
 322                             pa->pa_modname, pa->pa_rulname);
 323                 }
 324         LIST_INSERT_HEAD(&V_pfil_hook_list, hook, hook_list);
 325         PFIL_UNLOCK();
 326
 327         return (hook);
 328 }
 329
 330 static int
 331 pfil_unlink(struct pfil_link_args *pa, pfil_head_t head, pfil_hook_t hook)
 332 {
 333         struct pfil_link *in, *out;
 334
 335         PFIL_LOCK_ASSERT();
 336
 337         if (pa->pa_flags & PFIL_IN) {
 338                 in = pfil_link_remove(&head->head_in, hook);
 339                 if (in != NULL) {
 340                         head->head_nhooksin--;
 341                         hook->hook_links--;
 342                 }
 343         } else
 344                 in = NULL;
 345         if (pa->pa_flags & PFIL_OUT) {
 346                 out = pfil_link_remove(&head->head_out, hook);
 347                 if (out != NULL) {
 348                         head->head_nhooksout--;
 349                         hook->hook_links--;
 350                 }
 351         } else
 352                 out = NULL;
 353         PFIL_UNLOCK();
 354
 355         if (in != NULL)
 356                 NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
 357         if (out != NULL)
 358                 NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
 359
 360         if (in == NULL && out == NULL)
 361                 return (ENOENT);
 362         else
 363                 return (0);
 364 }
 365
 366 int
 367 pfil_link(struct pfil_link_args *pa)
 368 {
 369         struct pfil_link *in, *out, *link;
 370         struct pfil_head *head;
 371         struct pfil_hook *hook;
 372         int error;
 373
 374         MPASS(pa->pa_version == PFIL_VERSION);
 375
 376         if ((pa->pa_flags & (PFIL_IN | PFIL_UNLINK)) == PFIL_IN)
 377                 in = malloc(sizeof(*in), M_PFIL, M_WAITOK | M_ZERO);
 378         else
 379                 in = NULL;
 380         if ((pa->pa_flags & (PFIL_OUT | PFIL_UNLINK)) == PFIL_OUT)
 381                 out = malloc(sizeof(*out), M_PFIL, M_WAITOK | M_ZERO);
 382         else
 383                 out = NULL;
 384
 385         PFIL_LOCK();
 386         if (pa->pa_flags & PFIL_HEADPTR)
 387                 head = pa->pa_head;
 388         else
 389                 LIST_FOREACH(head, &V_pfil_head_list, head_list)
 390                         if (strcmp(pa->pa_headname, head->head_name) == 0)
 391                                 break;
 392         if (pa->pa_flags & PFIL_HOOKPTR)
 393                 hook = pa->pa_hook;
 394         else
 395                 LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
 396                         if (strcmp(pa->pa_modname, hook->hook_modname) == 0 &&
 397                             strcmp(pa->pa_rulname, hook->hook_rulname) == 0)
 398                                 break;
 399         if (head == NULL || hook == NULL) {
 400                 error = ENOENT;
 401                 goto fail;
 402         }
 403
 404         if (pa->pa_flags & PFIL_UNLINK)
 405                 return (pfil_unlink(pa, head, hook));
 406
 407         if (head->head_type != hook->hook_type ||
 408             ((hook->hook_flags & pa->pa_flags) & ~head->head_flags)) {
 409                 error = EINVAL;
 410                 goto fail;
 411         }
 412
 413         if (pa->pa_flags & PFIL_IN)
 414                 CK_STAILQ_FOREACH(link, &head->head_in, link_chain)
 415                         if (link->link_hook == hook) {
 416                                 error = EEXIST;
 417                                 goto fail;
 418                         }
 419         if (pa->pa_flags & PFIL_OUT)
 420                 CK_STAILQ_FOREACH(link, &head->head_out, link_chain)
 421                         if (link->link_hook == hook) {
 422                                 error = EEXIST;
 423                                 goto fail;
 424                         }
 425
 426         if (pa->pa_flags & PFIL_IN) {
 427                 in->link_hook = hook;
 428                 in->link_mbuf_chk = hook->hook_mbuf_chk;
 429                 in->link_mem_chk = hook->hook_mem_chk;
 430                 in->link_flags = hook->hook_flags;
 431                 in->link_ruleset = hook->hook_ruleset;
 432                 if (pa->pa_flags & PFIL_APPEND)
 433                         CK_STAILQ_INSERT_TAIL(&head->head_in, in, link_chain);
 434                 else
 435                         CK_STAILQ_INSERT_HEAD(&head->head_in, in, link_chain);
 436                 hook->hook_links++;
 437                 head->head_nhooksin++;
 438         }
 439         if (pa->pa_flags & PFIL_OUT) {
 440                 out->link_hook = hook;
 441                 out->link_mbuf_chk = hook->hook_mbuf_chk;
 442                 out->link_mem_chk = hook->hook_mem_chk;
 443                 out->link_flags = hook->hook_flags;
 444                 out->link_ruleset = hook->hook_ruleset;
 445                 if (pa->pa_flags & PFIL_APPEND)
 446                         CK_STAILQ_INSERT_HEAD(&head->head_out, out, link_chain);
 447                 else
 448                         CK_STAILQ_INSERT_TAIL(&head->head_out, out, link_chain);
 449                 hook->hook_links++;
 450                 head->head_nhooksout++;
 451         }
 452         PFIL_UNLOCK();
 453
 454         return (0);
 455
 456 fail:
 457         PFIL_UNLOCK();
 458         free(in, M_PFIL);
 459         free(out, M_PFIL);
 460         return (error);
 461 }
 462
 463 static void
 464 pfil_link_free(epoch_context_t ctx)
 465 {
 466         struct pfil_link *link;
 467
 468         link = __containerof(ctx, struct pfil_link, link_epoch_ctx);
 469         free(link, M_PFIL);
 470 }
 471
 472 /*
 473  * pfil_remove_hook removes a filter from all filtering points.
 474  */
 475 void
 476 pfil_remove_hook(pfil_hook_t hook)
 477 {
 478         struct pfil_head *head;
 479         struct pfil_link *in, *out;
 480
 481         PFIL_LOCK();
 482         LIST_FOREACH(head, &V_pfil_head_list, head_list) {
 483 retry:
 484                 in = pfil_link_remove(&head->head_in, hook);
 485                 if (in != NULL) {
 486                         head->head_nhooksin--;
 487                         hook->hook_links--;
 488                         NET_EPOCH_CALL(pfil_link_free, &in->link_epoch_ctx);
 489                 }
 490                 out = pfil_link_remove(&head->head_out, hook);
 491                 if (out != NULL) {
 492                         head->head_nhooksout--;
 493                         hook->hook_links--;
 494                         NET_EPOCH_CALL(pfil_link_free, &out->link_epoch_ctx);
 495                 }
 496                 if (in != NULL || out != NULL)
 497                         /* What if some stupid admin put same filter twice? */
 498                         goto retry;
 499         }
 500         LIST_REMOVE(hook, hook_list);
 501         PFIL_UNLOCK();
 502         MPASS(hook->hook_links == 0);
 503         free(hook, M_PFIL);
 504 }
 505
 506 /*
 507  * Internal: Remove a pfil hook from a hook chain.
 508  */
 509 static struct pfil_link *
 510 pfil_link_remove(pfil_chain_t *chain, pfil_hook_t hook)
 511 {
 512         struct pfil_link *link;
 513
 514         PFIL_LOCK_ASSERT();
 515
 516         CK_STAILQ_FOREACH(link, chain, link_chain)
 517                 if (link->link_hook == hook) {
 518                         CK_STAILQ_REMOVE(chain, link, pfil_link, link_chain);
 519                         return (link);
 520                 }
 521
 522         return (NULL);
 523 }
 524
 525 static void
 526 pfil_init(const void *unused __unused)
 527 {
 528         struct make_dev_args args;
 529         int error __diagused;
 530
 531         make_dev_args_init(&args);
 532         args.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
 533         args.mda_devsw = &pfil_cdevsw;
 534         args.mda_uid = UID_ROOT;
 535         args.mda_gid = GID_WHEEL;
 536         args.mda_mode = 0600;
 537         error = make_dev_s(&args, &pfil_dev, PFILDEV);
 538         KASSERT(error == 0, ("%s: failed to create dev: %d", __func__, error));
 539 }
 540 /*
 541  * Make sure the pfil bits are first before any possible subsystem which
 542  * might piggyback on the SI_SUB_PROTO_PFIL.
 543  */
 544 SYSINIT(pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST, pfil_init, NULL);
 545
 546 /*
 547  * User control interface.
 548  */
 549 static int pfilioc_listheads(struct pfilioc_list *);
 550 static int pfilioc_listhooks(struct pfilioc_list *);
 551 static int pfilioc_link(struct pfilioc_link *);
 552
 553 static int
 554 pfil_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
 555     struct thread *td)
 556 {
 557         int error;
 558
 559         CURVNET_SET(TD_TO_VNET(td));
 560         error = 0;
 561         switch (cmd) {
 562         case PFILIOC_LISTHEADS:
 563                 error = pfilioc_listheads((struct pfilioc_list *)addr);
 564                 break;
 565         case PFILIOC_LISTHOOKS:
 566                 error = pfilioc_listhooks((struct pfilioc_list *)addr);
 567                 break;
 568         case PFILIOC_LINK:
 569                 error = pfilioc_link((struct pfilioc_link *)addr);
 570                 break;
 571         default:
 572                 error = EINVAL;
 573                 break;
 574         }
 575         CURVNET_RESTORE();
 576         return (error);
 577 }
 578
 579 static int
 580 pfilioc_listheads(struct pfilioc_list *req)
 581 {
 582         struct pfil_head *head;
 583         struct pfil_link *link;
 584         struct pfilioc_head *iohead;
 585         struct pfilioc_hook *iohook;
 586         u_int nheads, nhooks, hd, hk;
 587         int error;
 588
 589         PFIL_LOCK();
 590 restart:
 591         nheads = nhooks = 0;
 592         LIST_FOREACH(head, &V_pfil_head_list, head_list) {
 593                 nheads++;
 594                 nhooks += head->head_nhooksin + head->head_nhooksout;
 595         }
 596         PFIL_UNLOCK();
 597
 598         if (req->pio_nheads < nheads || req->pio_nhooks < nhooks) {
 599                 req->pio_nheads = nheads;
 600                 req->pio_nhooks = nhooks;
 601                 return (0);
 602         }
 603
 604         iohead = malloc(sizeof(*iohead) * nheads, M_TEMP, M_WAITOK);
 605         iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
 606
 607         hd = hk = 0;
 608         PFIL_LOCK();
 609         LIST_FOREACH(head, &V_pfil_head_list, head_list) {
 610                 if (hd + 1 > nheads ||
 611                     hk + head->head_nhooksin + head->head_nhooksout > nhooks) {
 612                         /* Configuration changed during malloc(). */
 613                         free(iohead, M_TEMP);
 614                         free(iohook, M_TEMP);
 615                         goto restart;
 616                 }
 617                 strlcpy(iohead[hd].pio_name, head->head_name,
 618                         sizeof(iohead[0].pio_name));
 619                 iohead[hd].pio_nhooksin = head->head_nhooksin;
 620                 iohead[hd].pio_nhooksout = head->head_nhooksout;
 621                 iohead[hd].pio_type = head->head_type;
 622                 CK_STAILQ_FOREACH(link, &head->head_in, link_chain) {
 623                         strlcpy(iohook[hk].pio_module,
 624                             link->link_hook->hook_modname,
 625                             sizeof(iohook[0].pio_module));
 626                         strlcpy(iohook[hk].pio_ruleset,
 627                             link->link_hook->hook_rulname,
 628                             sizeof(iohook[0].pio_ruleset));
 629                         hk++;
 630                 }
 631                 CK_STAILQ_FOREACH(link, &head->head_out, link_chain) {
 632                         strlcpy(iohook[hk].pio_module,
 633                             link->link_hook->hook_modname,
 634                             sizeof(iohook[0].pio_module));
 635                         strlcpy(iohook[hk].pio_ruleset,
 636                             link->link_hook->hook_rulname,
 637                             sizeof(iohook[0].pio_ruleset));
 638                         hk++;
 639                 }
 640                 hd++;
 641         }
 642         PFIL_UNLOCK();
 643
 644         error = copyout(iohead, req->pio_heads,
 645             sizeof(*iohead) * min(hd, req->pio_nheads));
 646         if (error == 0)
 647                 error = copyout(iohook, req->pio_hooks,
 648                     sizeof(*iohook) * min(req->pio_nhooks, hk));
 649
 650         req->pio_nheads = hd;
 651         req->pio_nhooks = hk;
 652
 653         free(iohead, M_TEMP);
 654         free(iohook, M_TEMP);
 655
 656         return (error);
 657 }
 658
 659 static int
 660 pfilioc_listhooks(struct pfilioc_list *req)
 661 {
 662         struct pfil_hook *hook;
 663         struct pfilioc_hook *iohook;
 664         u_int nhooks, hk;
 665         int error;
 666
 667         PFIL_LOCK();
 668 restart:
 669         nhooks = 0;
 670         LIST_FOREACH(hook, &V_pfil_hook_list, hook_list)
 671                 nhooks++;
 672         PFIL_UNLOCK();
 673
 674         if (req->pio_nhooks < nhooks) {
 675                 req->pio_nhooks = nhooks;
 676                 return (0);
 677         }
 678
 679         iohook = malloc(sizeof(*iohook) * nhooks, M_TEMP, M_WAITOK);
 680
 681         hk = 0;
 682         PFIL_LOCK();
 683         LIST_FOREACH(hook, &V_pfil_hook_list, hook_list) {
 684                 if (hk + 1 > nhooks) {
 685                         /* Configuration changed during malloc(). */
 686                         free(iohook, M_TEMP);
 687                         goto restart;
 688                 }
 689                 strlcpy(iohook[hk].pio_module, hook->hook_modname,
 690                     sizeof(iohook[0].pio_module));
 691                 strlcpy(iohook[hk].pio_ruleset, hook->hook_rulname,
 692                     sizeof(iohook[0].pio_ruleset));
 693                 iohook[hk].pio_type = hook->hook_type;
 694                 iohook[hk].pio_flags = hook->hook_flags;
 695                 hk++;
 696         }
 697         PFIL_UNLOCK();
 698
 699         error = copyout(iohook, req->pio_hooks,
 700             sizeof(*iohook) * min(req->pio_nhooks, hk));
 701         req->pio_nhooks = hk;
 702         free(iohook, M_TEMP);
 703
 704         return (error);
 705 }
 706
 707 static int
 708 pfilioc_link(struct pfilioc_link *req)
 709 {
 710         struct pfil_link_args args;
 711
 712         if (req->pio_flags & ~(PFIL_IN | PFIL_OUT | PFIL_UNLINK | PFIL_APPEND))
 713                 return (EINVAL);
 714
 715         args.pa_version = PFIL_VERSION;
 716         args.pa_flags = req->pio_flags;
 717         args.pa_headname = req->pio_name;
 718         args.pa_modname = req->pio_module;
 719         args.pa_rulname = req->pio_ruleset;
 720
 721         return (pfil_link(&args));
 722 }