pfil.c revision 241888
1120386Ssam/* $FreeBSD: head/sys/net/pfil.c 241888 2012-10-22 14:10:17Z melifaro $ */ 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 55120386Ssamstatic int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int); 56120386Ssam 5760317Sdarrenrstatic int pfil_list_remove(pfil_list_t *, 58198198Srwatson int (*)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *), 59198198Srwatson void *); 6060317Sdarrenr 61197952SjulianLIST_HEAD(pfilheadhead, pfil_head); 62197952SjulianVNET_DEFINE(struct pfilheadhead, pfil_head_list); 63197952Sjulian#define V_pfil_head_list VNET(pfil_head_list) 64241888SmelifaroVNET_DEFINE(struct rmlock, pfil_lock); 65241888Smelifaro#define V_pfil_lock VNET(pfil_lock) 66120386Ssam 67120386Ssam/* 68120386Ssam * pfil_run_hooks() runs the specified packet filter hooks. 69120386Ssam */ 70120386Ssamint 71120386Ssampfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp, 72135920Smlaier int dir, struct inpcb *inp) 73120386Ssam{ 74173904Smlaier struct rm_priotracker rmpt; 75120386Ssam struct packet_filter_hook *pfh; 76120386Ssam struct mbuf *m = *mp; 77120386Ssam int rv = 0; 78120386Ssam 79173904Smlaier PFIL_RLOCK(ph, &rmpt); 80155201Scsjp KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0")); 81120386Ssam for (pfh = pfil_hook_get(dir, ph); pfh != NULL; 82120386Ssam pfh = TAILQ_NEXT(pfh, pfil_link)) { 83120386Ssam if (pfh->pfil_func != NULL) { 84198198Srwatson rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir, 85198198Srwatson inp); 86120386Ssam if (rv != 0 || m == NULL) 87120386Ssam break; 88120386Ssam } 89120386Ssam } 90173904Smlaier PFIL_RUNLOCK(ph, &rmpt); 91120386Ssam *mp = m; 92120386Ssam return (rv); 93120386Ssam} 94120386Ssam 95120386Ssam/* 96241888Smelifaro * pfil_try_rlock() acquires rm reader lock for specified head 97241888Smelifaro * if this is immediately possible, 98241888Smelifaro */ 99241888Smelifaroint 100241888Smelifaropfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker) 101241888Smelifaro{ 102241888Smelifaro return PFIL_TRY_RLOCK(ph, tracker); 103241888Smelifaro} 104241888Smelifaro 105241888Smelifaro/* 106241888Smelifaro * pfil_rlock() acquires rm reader lock for specified head. 107241888Smelifaro */ 108241888Smelifarovoid 109241888Smelifaropfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker) 110241888Smelifaro{ 111241888Smelifaro PFIL_RLOCK(ph, tracker); 112241888Smelifaro} 113241888Smelifaro 114241888Smelifaro/* 115241888Smelifaro * pfil_runlock() releases reader lock for specified head. 116241888Smelifaro */ 117241888Smelifarovoid 118241888Smelifaropfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker) 119241888Smelifaro{ 120241888Smelifaro PFIL_RUNLOCK(ph, tracker); 121241888Smelifaro} 122241888Smelifaro 123241888Smelifaro/* 124241888Smelifaro * pfil_wlock() acquires writer lock for specified head. 125241888Smelifaro */ 126241888Smelifarovoid 127241888Smelifaropfil_wlock(struct pfil_head *ph) 128241888Smelifaro{ 129241888Smelifaro PFIL_WLOCK(ph); 130241888Smelifaro} 131241888Smelifaro 132241888Smelifaro/* 133241888Smelifaro * pfil_wunlock() releases writer lock for specified head. 134241888Smelifaro */ 135241888Smelifarovoid 136241888Smelifaropfil_wunlock(struct pfil_head *ph) 137241888Smelifaro{ 138241888Smelifaro PFIL_WUNLOCK(ph); 139241888Smelifaro} 140241888Smelifaro 141241888Smelifaro/* 142241888Smelifaro * pfil_wowned() releases writer lock for specified head. 143241888Smelifaro */ 144241888Smelifaroint 145241888Smelifaropfil_wowned(struct pfil_head *ph) 146241888Smelifaro{ 147241888Smelifaro return PFIL_WOWNED(ph); 148241888Smelifaro} 149241888Smelifaro/* 150198233Srwatson * pfil_head_register() registers a pfil_head with the packet filter hook 151198233Srwatson * mechanism. 152120386Ssam */ 153120386Ssamint 154120386Ssampfil_head_register(struct pfil_head *ph) 155120386Ssam{ 156120386Ssam struct pfil_head *lph; 157120386Ssam 158120386Ssam PFIL_LIST_LOCK(); 159197952Sjulian LIST_FOREACH(lph, &V_pfil_head_list, ph_list) { 160120386Ssam if (ph->ph_type == lph->ph_type && 161120386Ssam ph->ph_un.phu_val == lph->ph_un.phu_val) { 162120386Ssam PFIL_LIST_UNLOCK(); 163198233Srwatson return (EEXIST); 164120386Ssam } 165186187Srwatson } 166173904Smlaier PFIL_LOCK_INIT(ph); 167155201Scsjp ph->ph_nhooks = 0; 16860317Sdarrenr TAILQ_INIT(&ph->ph_in); 16960317Sdarrenr TAILQ_INIT(&ph->ph_out); 170197952Sjulian LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list); 171120386Ssam PFIL_LIST_UNLOCK(); 172120386Ssam return (0); 17360317Sdarrenr} 17460317Sdarrenr 17560317Sdarrenr/* 176186187Srwatson * pfil_head_unregister() removes a pfil_head from the packet filter hook 177186187Srwatson * mechanism. The producer of the hook promises that all outstanding 178186187Srwatson * invocations of the hook have completed before it unregisters the hook. 179120386Ssam */ 180120386Ssamint 181120386Ssampfil_head_unregister(struct pfil_head *ph) 182120386Ssam{ 183120386Ssam struct packet_filter_hook *pfh, *pfnext; 184120386Ssam 185120386Ssam PFIL_LIST_LOCK(); 186120386Ssam LIST_REMOVE(ph, ph_list); 187120386Ssam PFIL_LIST_UNLOCK(); 188120386Ssam TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext) 189120386Ssam free(pfh, M_IFADDR); 190120386Ssam TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext) 191120386Ssam free(pfh, M_IFADDR); 192173904Smlaier PFIL_LOCK_DESTROY(ph); 193120386Ssam return (0); 194120386Ssam} 195120386Ssam 196120386Ssam/* 197120386Ssam * pfil_head_get() returns the pfil_head for a given key/dlt. 198120386Ssam */ 199120386Ssamstruct pfil_head * 200120386Ssampfil_head_get(int type, u_long val) 201120386Ssam{ 202120386Ssam struct pfil_head *ph; 203120386Ssam 204120386Ssam PFIL_LIST_LOCK(); 205197952Sjulian LIST_FOREACH(ph, &V_pfil_head_list, ph_list) 206120386Ssam if (ph->ph_type == type && ph->ph_un.phu_val == val) 207120386Ssam break; 208120386Ssam PFIL_LIST_UNLOCK(); 209120386Ssam return (ph); 210120386Ssam} 211120386Ssam 212120386Ssam/* 21360317Sdarrenr * pfil_add_hook() adds a function to the packet filter hook. the 21460317Sdarrenr * flags are: 21560317Sdarrenr * PFIL_IN call me on incoming packets 21660317Sdarrenr * PFIL_OUT call me on outgoing packets 21760317Sdarrenr * PFIL_ALL call me on all of the above 218111119Simp * PFIL_WAITOK OK to call malloc with M_WAITOK. 21960317Sdarrenr */ 22060317Sdarrenrint 221186187Srwatsonpfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, 222186187Srwatson struct inpcb *), void *arg, int flags, struct pfil_head *ph) 22360317Sdarrenr{ 224120386Ssam struct packet_filter_hook *pfh1 = NULL; 225120386Ssam struct packet_filter_hook *pfh2 = NULL; 226120386Ssam int err; 22760317Sdarrenr 228120386Ssam if (flags & PFIL_IN) { 229120386Ssam pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 230120386Ssam M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT); 231120386Ssam if (pfh1 == NULL) { 232120386Ssam err = ENOMEM; 233120386Ssam goto error; 234120386Ssam } 235120386Ssam } 236120386Ssam if (flags & PFIL_OUT) { 237120386Ssam pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 238120386Ssam M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT); 239120386Ssam if (pfh2 == NULL) { 240120386Ssam err = ENOMEM; 241120386Ssam goto error; 242120386Ssam } 243120386Ssam } 244155201Scsjp PFIL_WLOCK(ph); 245120386Ssam if (flags & PFIL_IN) { 246120386Ssam pfh1->pfil_func = func; 247120386Ssam pfh1->pfil_arg = arg; 248120386Ssam err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT); 249120386Ssam if (err) 250186187Srwatson goto locked_error; 251155201Scsjp ph->ph_nhooks++; 252120386Ssam } 253120386Ssam if (flags & PFIL_OUT) { 254120386Ssam pfh2->pfil_func = func; 255120386Ssam pfh2->pfil_arg = arg; 256120386Ssam err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN); 257120386Ssam if (err) { 258120386Ssam if (flags & PFIL_IN) 259120386Ssam pfil_list_remove(&ph->ph_in, func, arg); 260186187Srwatson goto locked_error; 261120386Ssam } 262155201Scsjp ph->ph_nhooks++; 263120386Ssam } 264120386Ssam PFIL_WUNLOCK(ph); 265198233Srwatson return (0); 266186187Srwatsonlocked_error: 267120386Ssam PFIL_WUNLOCK(ph); 268120386Ssamerror: 269120386Ssam if (pfh1 != NULL) 270120386Ssam free(pfh1, M_IFADDR); 271120386Ssam if (pfh2 != NULL) 272120386Ssam free(pfh2, M_IFADDR); 273198233Srwatson return (err); 27460317Sdarrenr} 27560317Sdarrenr 27660317Sdarrenr/* 277198233Srwatson * pfil_remove_hook removes a specific function from the packet filter hook 278198233Srwatson * list. 27960317Sdarrenr */ 28060317Sdarrenrint 281198198Srwatsonpfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, 282198198Srwatson struct inpcb *), void *arg, int flags, struct pfil_head *ph) 28360317Sdarrenr{ 28460317Sdarrenr int err = 0; 28560317Sdarrenr 286155201Scsjp PFIL_WLOCK(ph); 287155201Scsjp if (flags & PFIL_IN) { 288120386Ssam err = pfil_list_remove(&ph->ph_in, func, arg); 289155201Scsjp if (err == 0) 290155201Scsjp ph->ph_nhooks--; 291155201Scsjp } 292155201Scsjp if ((err == 0) && (flags & PFIL_OUT)) { 293120386Ssam err = pfil_list_remove(&ph->ph_out, func, arg); 294155201Scsjp if (err == 0) 295155201Scsjp ph->ph_nhooks--; 296155201Scsjp } 297120386Ssam PFIL_WUNLOCK(ph); 298198233Srwatson return (err); 29960317Sdarrenr} 30060317Sdarrenr 301120386Ssamstatic int 302120386Ssampfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags) 303120386Ssam{ 304120386Ssam struct packet_filter_hook *pfh; 305120386Ssam 306120386Ssam /* 307120386Ssam * First make sure the hook is not already there. 308120386Ssam */ 309120386Ssam TAILQ_FOREACH(pfh, list, pfil_link) 310120386Ssam if (pfh->pfil_func == pfh1->pfil_func && 311120386Ssam pfh->pfil_arg == pfh1->pfil_arg) 312198233Srwatson return (EEXIST); 313198233Srwatson 314120386Ssam /* 315198233Srwatson * Insert the input list in reverse order of the output list so that 316198233Srwatson * the same path is followed in or out of the kernel. 317120386Ssam */ 318120386Ssam if (flags & PFIL_IN) 319120386Ssam TAILQ_INSERT_HEAD(list, pfh1, pfil_link); 320120386Ssam else 321120386Ssam TAILQ_INSERT_TAIL(list, pfh1, pfil_link); 322198233Srwatson return (0); 323120386Ssam} 324120386Ssam 32560317Sdarrenr/* 32660317Sdarrenr * pfil_list_remove is an internal function that takes a function off the 32760317Sdarrenr * specified list. 32860317Sdarrenr */ 32960317Sdarrenrstatic int 330120386Ssampfil_list_remove(pfil_list_t *list, 331198198Srwatson int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *), 332198198Srwatson void *arg) 33360317Sdarrenr{ 33460317Sdarrenr struct packet_filter_hook *pfh; 33560317Sdarrenr 33671999Sphk TAILQ_FOREACH(pfh, list, pfil_link) 337120386Ssam if (pfh->pfil_func == func && pfh->pfil_arg == arg) { 33860317Sdarrenr TAILQ_REMOVE(list, pfh, pfil_link); 33960317Sdarrenr free(pfh, M_IFADDR); 340198233Srwatson return (0); 34160317Sdarrenr } 342198233Srwatson return (ENOENT); 34360317Sdarrenr} 344197952Sjulian 345198233Srwatson/* 346198233Srwatson * Stuff that must be initialized for every instance (including the first of 347198233Srwatson * course). 348197952Sjulian */ 349197952Sjulianstatic int 350197952Sjulianvnet_pfil_init(const void *unused) 351197952Sjulian{ 352198233Srwatson 353197952Sjulian LIST_INIT(&V_pfil_head_list); 354241888Smelifaro PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared"); 355197952Sjulian return (0); 356197952Sjulian} 357197952Sjulian 358198233Srwatson/* 359197952Sjulian * Called for the removal of each instance. 360197952Sjulian */ 361197952Sjulianstatic int 362197952Sjulianvnet_pfil_uninit(const void *unused) 363197952Sjulian{ 364198233Srwatson 365197952Sjulian /* XXX should panic if list is not empty */ 366241888Smelifaro PFIL_LOCK_DESTROY_REAL(&V_pfil_lock); 367198233Srwatson return (0); 368197952Sjulian} 369197952Sjulian 370197952Sjulian/* Define startup order. */ 371197952Sjulian#define PFIL_SYSINIT_ORDER SI_SUB_PROTO_BEGIN 372197952Sjulian#define PFIL_MODEVENT_ORDER (SI_ORDER_FIRST) /* On boot slot in here. */ 373197952Sjulian#define PFIL_VNET_ORDER (PFIL_MODEVENT_ORDER + 2) /* Later still. */ 374197952Sjulian 375197952Sjulian/* 376198233Srwatson * Starting up. 377198233Srwatson * 378197952Sjulian * VNET_SYSINIT is called for each existing vnet and each new vnet. 379197952Sjulian */ 380197952SjulianVNET_SYSINIT(vnet_pfil_init, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER, 381198233Srwatson vnet_pfil_init, NULL); 382197952Sjulian 383197952Sjulian/* 384198233Srwatson * Closing up shop. These are done in REVERSE ORDER. Not called on reboot. 385198233Srwatson * 386197952Sjulian * VNET_SYSUNINIT is called for each exiting vnet as it exits. 387197952Sjulian */ 388197952SjulianVNET_SYSUNINIT(vnet_pfil_uninit, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER, 389198233Srwatson vnet_pfil_uninit, NULL); 390