pfil.c revision 254774
1120386Ssam/* $FreeBSD: head/sys/net/pfil.c 254774 2013-08-24 11:24:15Z andre $ */ 2120386Ssam/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */ 360317Sdarrenr 4139823Simp/*- 560317Sdarrenr * Copyright (c) 1996 Matthew R. Green 660317Sdarrenr * All rights reserved. 760317Sdarrenr * 860317Sdarrenr * Redistribution and use in source and binary forms, with or without 960317Sdarrenr * modification, are permitted provided that the following conditions 1060317Sdarrenr * are met: 1160317Sdarrenr * 1. Redistributions of source code must retain the above copyright 1260317Sdarrenr * notice, this list of conditions and the following disclaimer. 1360317Sdarrenr * 2. Redistributions in binary form must reproduce the above copyright 1460317Sdarrenr * notice, this list of conditions and the following disclaimer in the 1560317Sdarrenr * documentation and/or other materials provided with the distribution. 1660317Sdarrenr * 3. The name of the author may not be used to endorse or promote products 1760317Sdarrenr * derived from this software without specific prior written permission. 1860317Sdarrenr * 1960317Sdarrenr * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 2060317Sdarrenr * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 2160317Sdarrenr * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 2260317Sdarrenr * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 2360317Sdarrenr * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 2460317Sdarrenr * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 2560317Sdarrenr * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 2660317Sdarrenr * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 2760317Sdarrenr * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2860317Sdarrenr * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2960317Sdarrenr * SUCH DAMAGE. 3060317Sdarrenr */ 3160317Sdarrenr 3260317Sdarrenr#include <sys/param.h> 33120386Ssam#include <sys/kernel.h> 3460317Sdarrenr#include <sys/errno.h> 35155201Scsjp#include <sys/lock.h> 3660317Sdarrenr#include <sys/malloc.h> 37173904Smlaier#include <sys/rmlock.h> 3860317Sdarrenr#include <sys/socket.h> 3960317Sdarrenr#include <sys/socketvar.h> 4060317Sdarrenr#include <sys/systm.h> 41120386Ssam#include <sys/condvar.h> 42120386Ssam#include <sys/lock.h> 43120386Ssam#include <sys/mutex.h> 44120386Ssam#include <sys/proc.h> 4560317Sdarrenr#include <sys/queue.h> 4660317Sdarrenr 4760317Sdarrenr#include <net/if.h> 4860317Sdarrenr#include <net/pfil.h> 4960317Sdarrenr 50120386Ssamstatic struct mtx pfil_global_lock; 51120386Ssam 52198198SrwatsonMTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock", 53198198Srwatson MTX_DEF); 54120386Ssam 55254773Sandrestatic struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *); 56254773Sandrestatic int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int); 57254773Sandrestatic int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *); 58120386Ssam 59197952SjulianLIST_HEAD(pfilheadhead, pfil_head); 60197952SjulianVNET_DEFINE(struct pfilheadhead, pfil_head_list); 61197952Sjulian#define V_pfil_head_list VNET(pfil_head_list) 62241888SmelifaroVNET_DEFINE(struct rmlock, pfil_lock); 63241888Smelifaro#define V_pfil_lock VNET(pfil_lock) 64120386Ssam 65120386Ssam/* 66254773Sandre * pfil_run_hooks() runs the specified packet filter hook chain. 67120386Ssam */ 68120386Ssamint 69120386Ssampfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp, 70135920Smlaier int dir, struct inpcb *inp) 71120386Ssam{ 72173904Smlaier struct rm_priotracker rmpt; 73120386Ssam struct packet_filter_hook *pfh; 74120386Ssam struct mbuf *m = *mp; 75120386Ssam int rv = 0; 76120386Ssam 77173904Smlaier PFIL_RLOCK(ph, &rmpt); 78155201Scsjp KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0")); 79254773Sandre for (pfh = pfil_chain_get(dir, ph); pfh != NULL; 80254773Sandre pfh = TAILQ_NEXT(pfh, pfil_chain)) { 81120386Ssam if (pfh->pfil_func != NULL) { 82198198Srwatson rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir, 83198198Srwatson inp); 84120386Ssam if (rv != 0 || m == NULL) 85120386Ssam break; 86120386Ssam } 87120386Ssam } 88173904Smlaier PFIL_RUNLOCK(ph, &rmpt); 89120386Ssam *mp = m; 90120386Ssam return (rv); 91120386Ssam} 92120386Ssam 93254771Sandrestatic struct packet_filter_hook * 94254773Sandrepfil_chain_get(int dir, struct pfil_head *ph) 95254771Sandre{ 96254771Sandre 97254771Sandre if (dir == PFIL_IN) 98254771Sandre return (TAILQ_FIRST(&ph->ph_in)); 99254771Sandre else if (dir == PFIL_OUT) 100254771Sandre return (TAILQ_FIRST(&ph->ph_out)); 101254771Sandre else 102254771Sandre return (NULL); 103254771Sandre} 104254771Sandre 105120386Ssam/* 106241888Smelifaro * pfil_try_rlock() acquires rm reader lock for specified head 107248490Sae * if this is immediately possible. 108241888Smelifaro */ 109241888Smelifaroint 110241888Smelifaropfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker) 111241888Smelifaro{ 112248490Sae 113248490Sae return (PFIL_TRY_RLOCK(ph, tracker)); 114241888Smelifaro} 115241888Smelifaro 116241888Smelifaro/* 117241888Smelifaro * pfil_rlock() acquires rm reader lock for specified head. 118241888Smelifaro */ 119241888Smelifarovoid 120241888Smelifaropfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker) 121241888Smelifaro{ 122248490Sae 123241888Smelifaro PFIL_RLOCK(ph, tracker); 124241888Smelifaro} 125241888Smelifaro 126241888Smelifaro/* 127241888Smelifaro * pfil_runlock() releases reader lock for specified head. 128241888Smelifaro */ 129241888Smelifarovoid 130241888Smelifaropfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker) 131241888Smelifaro{ 132248490Sae 133241888Smelifaro PFIL_RUNLOCK(ph, tracker); 134241888Smelifaro} 135241888Smelifaro 136241888Smelifaro/* 137241888Smelifaro * pfil_wlock() acquires writer lock for specified head. 138241888Smelifaro */ 139241888Smelifarovoid 140241888Smelifaropfil_wlock(struct pfil_head *ph) 141241888Smelifaro{ 142248490Sae 143241888Smelifaro PFIL_WLOCK(ph); 144241888Smelifaro} 145241888Smelifaro 146241888Smelifaro/* 147241888Smelifaro * pfil_wunlock() releases writer lock for specified head. 148241888Smelifaro */ 149241888Smelifarovoid 150241888Smelifaropfil_wunlock(struct pfil_head *ph) 151241888Smelifaro{ 152248490Sae 153241888Smelifaro PFIL_WUNLOCK(ph); 154241888Smelifaro} 155241888Smelifaro 156241888Smelifaro/* 157248490Sae * pfil_wowned() returns a non-zero value if the current thread owns 158248490Sae * an exclusive lock. 159241888Smelifaro */ 160241888Smelifaroint 161241888Smelifaropfil_wowned(struct pfil_head *ph) 162241888Smelifaro{ 163248490Sae 164248490Sae return (PFIL_WOWNED(ph)); 165241888Smelifaro} 166254773Sandre 167241888Smelifaro/* 168198233Srwatson * pfil_head_register() registers a pfil_head with the packet filter hook 169198233Srwatson * mechanism. 170120386Ssam */ 171120386Ssamint 172120386Ssampfil_head_register(struct pfil_head *ph) 173120386Ssam{ 174120386Ssam struct pfil_head *lph; 175120386Ssam 176254774Sandre PFIL_HEADLIST_LOCK(); 177197952Sjulian LIST_FOREACH(lph, &V_pfil_head_list, ph_list) { 178120386Ssam if (ph->ph_type == lph->ph_type && 179120386Ssam ph->ph_un.phu_val == lph->ph_un.phu_val) { 180254774Sandre PFIL_HEADLIST_UNLOCK(); 181198233Srwatson return (EEXIST); 182120386Ssam } 183186187Srwatson } 184173904Smlaier PFIL_LOCK_INIT(ph); 185155201Scsjp ph->ph_nhooks = 0; 18660317Sdarrenr TAILQ_INIT(&ph->ph_in); 18760317Sdarrenr TAILQ_INIT(&ph->ph_out); 188197952Sjulian LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list); 189254774Sandre PFIL_HEADLIST_UNLOCK(); 190120386Ssam return (0); 19160317Sdarrenr} 19260317Sdarrenr 19360317Sdarrenr/* 194186187Srwatson * pfil_head_unregister() removes a pfil_head from the packet filter hook 195186187Srwatson * mechanism. The producer of the hook promises that all outstanding 196186187Srwatson * invocations of the hook have completed before it unregisters the hook. 197120386Ssam */ 198120386Ssamint 199120386Ssampfil_head_unregister(struct pfil_head *ph) 200120386Ssam{ 201120386Ssam struct packet_filter_hook *pfh, *pfnext; 202120386Ssam 203254774Sandre PFIL_HEADLIST_LOCK(); 204120386Ssam LIST_REMOVE(ph, ph_list); 205254774Sandre PFIL_HEADLIST_UNLOCK(); 206254773Sandre TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext) 207120386Ssam free(pfh, M_IFADDR); 208254773Sandre TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext) 209120386Ssam free(pfh, M_IFADDR); 210173904Smlaier PFIL_LOCK_DESTROY(ph); 211120386Ssam return (0); 212120386Ssam} 213120386Ssam 214120386Ssam/* 215120386Ssam * pfil_head_get() returns the pfil_head for a given key/dlt. 216120386Ssam */ 217120386Ssamstruct pfil_head * 218120386Ssampfil_head_get(int type, u_long val) 219120386Ssam{ 220120386Ssam struct pfil_head *ph; 221120386Ssam 222254774Sandre PFIL_HEADLIST_LOCK(); 223197952Sjulian LIST_FOREACH(ph, &V_pfil_head_list, ph_list) 224120386Ssam if (ph->ph_type == type && ph->ph_un.phu_val == val) 225120386Ssam break; 226254774Sandre PFIL_HEADLIST_UNLOCK(); 227120386Ssam return (ph); 228120386Ssam} 229120386Ssam 230120386Ssam/* 23160317Sdarrenr * pfil_add_hook() adds a function to the packet filter hook. the 23260317Sdarrenr * flags are: 23360317Sdarrenr * PFIL_IN call me on incoming packets 23460317Sdarrenr * PFIL_OUT call me on outgoing packets 23560317Sdarrenr * PFIL_ALL call me on all of the above 236111119Simp * PFIL_WAITOK OK to call malloc with M_WAITOK. 23760317Sdarrenr */ 23860317Sdarrenrint 239254769Sandrepfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph) 24060317Sdarrenr{ 241120386Ssam struct packet_filter_hook *pfh1 = NULL; 242120386Ssam struct packet_filter_hook *pfh2 = NULL; 243120386Ssam int err; 24460317Sdarrenr 245120386Ssam if (flags & PFIL_IN) { 246120386Ssam pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 247120386Ssam M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT); 248120386Ssam if (pfh1 == NULL) { 249120386Ssam err = ENOMEM; 250120386Ssam goto error; 251120386Ssam } 252120386Ssam } 253120386Ssam if (flags & PFIL_OUT) { 254120386Ssam pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 255120386Ssam M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT); 256120386Ssam if (pfh2 == NULL) { 257120386Ssam err = ENOMEM; 258120386Ssam goto error; 259120386Ssam } 260120386Ssam } 261155201Scsjp PFIL_WLOCK(ph); 262120386Ssam if (flags & PFIL_IN) { 263120386Ssam pfh1->pfil_func = func; 264120386Ssam pfh1->pfil_arg = arg; 265254773Sandre err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT); 266120386Ssam if (err) 267186187Srwatson goto locked_error; 268155201Scsjp ph->ph_nhooks++; 269120386Ssam } 270120386Ssam if (flags & PFIL_OUT) { 271120386Ssam pfh2->pfil_func = func; 272120386Ssam pfh2->pfil_arg = arg; 273254773Sandre err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN); 274120386Ssam if (err) { 275120386Ssam if (flags & PFIL_IN) 276254773Sandre pfil_chain_remove(&ph->ph_in, func, arg); 277186187Srwatson goto locked_error; 278120386Ssam } 279155201Scsjp ph->ph_nhooks++; 280120386Ssam } 281120386Ssam PFIL_WUNLOCK(ph); 282198233Srwatson return (0); 283186187Srwatsonlocked_error: 284120386Ssam PFIL_WUNLOCK(ph); 285120386Ssamerror: 286120386Ssam if (pfh1 != NULL) 287120386Ssam free(pfh1, M_IFADDR); 288120386Ssam if (pfh2 != NULL) 289120386Ssam free(pfh2, M_IFADDR); 290198233Srwatson return (err); 29160317Sdarrenr} 29260317Sdarrenr 29360317Sdarrenr/* 294198233Srwatson * pfil_remove_hook removes a specific function from the packet filter hook 295254773Sandre * chain. 29660317Sdarrenr */ 29760317Sdarrenrint 298254769Sandrepfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph) 29960317Sdarrenr{ 30060317Sdarrenr int err = 0; 30160317Sdarrenr 302155201Scsjp PFIL_WLOCK(ph); 303155201Scsjp if (flags & PFIL_IN) { 304254773Sandre err = pfil_chain_remove(&ph->ph_in, func, arg); 305155201Scsjp if (err == 0) 306155201Scsjp ph->ph_nhooks--; 307155201Scsjp } 308155201Scsjp if ((err == 0) && (flags & PFIL_OUT)) { 309254773Sandre err = pfil_chain_remove(&ph->ph_out, func, arg); 310155201Scsjp if (err == 0) 311155201Scsjp ph->ph_nhooks--; 312155201Scsjp } 313120386Ssam PFIL_WUNLOCK(ph); 314198233Srwatson return (err); 31560317Sdarrenr} 31660317Sdarrenr 317254773Sandre/* 318254773Sandre * Internal: Add a new pfil hook into a hook chain. 319254773Sandre */ 320120386Ssamstatic int 321254773Sandrepfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags) 322120386Ssam{ 323120386Ssam struct packet_filter_hook *pfh; 324120386Ssam 325120386Ssam /* 326120386Ssam * First make sure the hook is not already there. 327120386Ssam */ 328254773Sandre TAILQ_FOREACH(pfh, chain, pfil_chain) 329120386Ssam if (pfh->pfil_func == pfh1->pfil_func && 330120386Ssam pfh->pfil_arg == pfh1->pfil_arg) 331198233Srwatson return (EEXIST); 332198233Srwatson 333120386Ssam /* 334198233Srwatson * Insert the input list in reverse order of the output list so that 335198233Srwatson * the same path is followed in or out of the kernel. 336120386Ssam */ 337120386Ssam if (flags & PFIL_IN) 338254773Sandre TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain); 339120386Ssam else 340254773Sandre TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain); 341198233Srwatson return (0); 342120386Ssam} 343120386Ssam 34460317Sdarrenr/* 345254773Sandre * Internal: Remove a pfil hook from a hook chain. 34660317Sdarrenr */ 34760317Sdarrenrstatic int 348254773Sandrepfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg) 34960317Sdarrenr{ 35060317Sdarrenr struct packet_filter_hook *pfh; 35160317Sdarrenr 352254773Sandre TAILQ_FOREACH(pfh, chain, pfil_chain) 353120386Ssam if (pfh->pfil_func == func && pfh->pfil_arg == arg) { 354254773Sandre TAILQ_REMOVE(chain, pfh, pfil_chain); 35560317Sdarrenr free(pfh, M_IFADDR); 356198233Srwatson return (0); 35760317Sdarrenr } 358198233Srwatson return (ENOENT); 35960317Sdarrenr} 360197952Sjulian 361198233Srwatson/* 362198233Srwatson * Stuff that must be initialized for every instance (including the first of 363198233Srwatson * course). 364197952Sjulian */ 365197952Sjulianstatic int 366197952Sjulianvnet_pfil_init(const void *unused) 367197952Sjulian{ 368198233Srwatson 369197952Sjulian LIST_INIT(&V_pfil_head_list); 370241888Smelifaro PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared"); 371197952Sjulian return (0); 372197952Sjulian} 373197952Sjulian 374198233Srwatson/* 375197952Sjulian * Called for the removal of each instance. 376197952Sjulian */ 377197952Sjulianstatic int 378197952Sjulianvnet_pfil_uninit(const void *unused) 379197952Sjulian{ 380198233Srwatson 381254773Sandre KASSERT(LIST_EMPTY(&V_pfil_head_list), 382254773Sandre ("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list)); 383241888Smelifaro PFIL_LOCK_DESTROY_REAL(&V_pfil_lock); 384198233Srwatson return (0); 385197952Sjulian} 386197952Sjulian 387197952Sjulian/* Define startup order. */ 388197952Sjulian#define PFIL_SYSINIT_ORDER SI_SUB_PROTO_BEGIN 389197952Sjulian#define PFIL_MODEVENT_ORDER (SI_ORDER_FIRST) /* On boot slot in here. */ 390197952Sjulian#define PFIL_VNET_ORDER (PFIL_MODEVENT_ORDER + 2) /* Later still. */ 391197952Sjulian 392197952Sjulian/* 393198233Srwatson * Starting up. 394198233Srwatson * 395197952Sjulian * VNET_SYSINIT is called for each existing vnet and each new vnet. 396197952Sjulian */ 397197952SjulianVNET_SYSINIT(vnet_pfil_init, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER, 398198233Srwatson vnet_pfil_init, NULL); 399197952Sjulian 400197952Sjulian/* 401198233Srwatson * Closing up shop. These are done in REVERSE ORDER. Not called on reboot. 402198233Srwatson * 403197952Sjulian * VNET_SYSUNINIT is called for each exiting vnet as it exits. 404197952Sjulian */ 405197952SjulianVNET_SYSUNINIT(vnet_pfil_uninit, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER, 406198233Srwatson vnet_pfil_uninit, NULL); 407