403 lines
9.7 KiB
C
403 lines
9.7 KiB
C
/* $FreeBSD$ */
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/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
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/*-
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* Copyright (c) 1996 Matthew R. Green
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/errno.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/rmlock.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/systm.h>
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#include <sys/condvar.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/pfil.h>
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static struct mtx pfil_global_lock;
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MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
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MTX_DEF);
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static struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
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static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
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static int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *);
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LIST_HEAD(pfilheadhead, pfil_head);
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VNET_DEFINE(struct pfilheadhead, pfil_head_list);
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#define V_pfil_head_list VNET(pfil_head_list)
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VNET_DEFINE(struct rmlock, pfil_lock);
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#define V_pfil_lock VNET(pfil_lock)
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/*
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* pfil_run_hooks() runs the specified packet filter hook chain.
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*/
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int
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pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
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int dir, struct inpcb *inp)
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{
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struct rm_priotracker rmpt;
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struct packet_filter_hook *pfh;
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struct mbuf *m = *mp;
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int rv = 0;
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PFIL_RLOCK(ph, &rmpt);
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KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
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for (pfh = pfil_chain_get(dir, ph); pfh != NULL;
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pfh = TAILQ_NEXT(pfh, pfil_chain)) {
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if (pfh->pfil_func != NULL) {
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rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
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inp);
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if (rv != 0 || m == NULL)
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break;
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}
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}
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PFIL_RUNLOCK(ph, &rmpt);
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*mp = m;
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return (rv);
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}
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static struct packet_filter_hook *
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pfil_chain_get(int dir, struct pfil_head *ph)
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{
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if (dir == PFIL_IN)
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return (TAILQ_FIRST(&ph->ph_in));
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else if (dir == PFIL_OUT)
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return (TAILQ_FIRST(&ph->ph_out));
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else
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return (NULL);
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}
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/*
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* pfil_try_rlock() acquires rm reader lock for specified head
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* if this is immediately possible.
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*/
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int
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pfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
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{
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return (PFIL_TRY_RLOCK(ph, tracker));
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}
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/*
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* pfil_rlock() acquires rm reader lock for specified head.
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*/
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void
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pfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
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{
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PFIL_RLOCK(ph, tracker);
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}
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/*
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* pfil_runlock() releases reader lock for specified head.
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*/
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void
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pfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker)
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{
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PFIL_RUNLOCK(ph, tracker);
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}
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/*
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* pfil_wlock() acquires writer lock for specified head.
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*/
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void
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pfil_wlock(struct pfil_head *ph)
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{
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PFIL_WLOCK(ph);
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}
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/*
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* pfil_wunlock() releases writer lock for specified head.
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*/
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void
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pfil_wunlock(struct pfil_head *ph)
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{
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PFIL_WUNLOCK(ph);
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}
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/*
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* pfil_wowned() returns a non-zero value if the current thread owns
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* an exclusive lock.
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*/
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int
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pfil_wowned(struct pfil_head *ph)
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{
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return (PFIL_WOWNED(ph));
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}
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/*
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* pfil_head_register() registers a pfil_head with the packet filter hook
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* mechanism.
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*/
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int
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pfil_head_register(struct pfil_head *ph)
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{
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struct pfil_head *lph;
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PFIL_HEADLIST_LOCK();
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LIST_FOREACH(lph, &V_pfil_head_list, ph_list) {
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if (ph->ph_type == lph->ph_type &&
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ph->ph_un.phu_val == lph->ph_un.phu_val) {
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PFIL_HEADLIST_UNLOCK();
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return (EEXIST);
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}
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}
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PFIL_LOCK_INIT(ph);
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ph->ph_nhooks = 0;
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TAILQ_INIT(&ph->ph_in);
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TAILQ_INIT(&ph->ph_out);
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LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list);
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PFIL_HEADLIST_UNLOCK();
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return (0);
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}
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/*
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* pfil_head_unregister() removes a pfil_head from the packet filter hook
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* mechanism. The producer of the hook promises that all outstanding
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* invocations of the hook have completed before it unregisters the hook.
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*/
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int
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pfil_head_unregister(struct pfil_head *ph)
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{
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struct packet_filter_hook *pfh, *pfnext;
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PFIL_HEADLIST_LOCK();
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LIST_REMOVE(ph, ph_list);
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PFIL_HEADLIST_UNLOCK();
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
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free(pfh, M_IFADDR);
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TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext)
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free(pfh, M_IFADDR);
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PFIL_LOCK_DESTROY(ph);
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return (0);
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}
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/*
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* pfil_head_get() returns the pfil_head for a given key/dlt.
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*/
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struct pfil_head *
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pfil_head_get(int type, u_long val)
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{
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struct pfil_head *ph;
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PFIL_HEADLIST_LOCK();
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LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
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if (ph->ph_type == type && ph->ph_un.phu_val == val)
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break;
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PFIL_HEADLIST_UNLOCK();
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return (ph);
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}
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/*
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* pfil_add_hook() adds a function to the packet filter hook. the
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* flags are:
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* PFIL_IN call me on incoming packets
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* PFIL_OUT call me on outgoing packets
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* PFIL_ALL call me on all of the above
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* PFIL_WAITOK OK to call malloc with M_WAITOK.
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*/
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int
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pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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{
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struct packet_filter_hook *pfh1 = NULL;
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struct packet_filter_hook *pfh2 = NULL;
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int err;
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if (flags & PFIL_IN) {
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pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
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M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
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if (pfh1 == NULL) {
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err = ENOMEM;
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goto error;
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}
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}
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if (flags & PFIL_OUT) {
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pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
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M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
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if (pfh2 == NULL) {
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err = ENOMEM;
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goto error;
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}
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}
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PFIL_WLOCK(ph);
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if (flags & PFIL_IN) {
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pfh1->pfil_func = func;
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pfh1->pfil_arg = arg;
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err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
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if (err)
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goto locked_error;
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ph->ph_nhooks++;
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}
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if (flags & PFIL_OUT) {
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pfh2->pfil_func = func;
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pfh2->pfil_arg = arg;
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err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
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if (err) {
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if (flags & PFIL_IN)
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pfil_chain_remove(&ph->ph_in, func, arg);
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goto locked_error;
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}
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ph->ph_nhooks++;
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}
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PFIL_WUNLOCK(ph);
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return (0);
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locked_error:
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PFIL_WUNLOCK(ph);
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error:
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if (pfh1 != NULL)
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free(pfh1, M_IFADDR);
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if (pfh2 != NULL)
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free(pfh2, M_IFADDR);
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return (err);
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}
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/*
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* pfil_remove_hook removes a specific function from the packet filter hook
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* chain.
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*/
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int
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pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
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{
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int err = 0;
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PFIL_WLOCK(ph);
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if (flags & PFIL_IN) {
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err = pfil_chain_remove(&ph->ph_in, func, arg);
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if (err == 0)
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ph->ph_nhooks--;
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}
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if ((err == 0) && (flags & PFIL_OUT)) {
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err = pfil_chain_remove(&ph->ph_out, func, arg);
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if (err == 0)
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ph->ph_nhooks--;
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}
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PFIL_WUNLOCK(ph);
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return (err);
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}
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/*
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* Internal: Add a new pfil hook into a hook chain.
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*/
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static int
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pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
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{
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struct packet_filter_hook *pfh;
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/*
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* First make sure the hook is not already there.
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*/
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TAILQ_FOREACH(pfh, chain, pfil_chain)
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if (pfh->pfil_func == pfh1->pfil_func &&
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pfh->pfil_arg == pfh1->pfil_arg)
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return (EEXIST);
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/*
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* Insert the input list in reverse order of the output list so that
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* the same path is followed in or out of the kernel.
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*/
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if (flags & PFIL_IN)
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TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain);
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else
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TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
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return (0);
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}
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/*
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* Internal: Remove a pfil hook from a hook chain.
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*/
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static int
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pfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg)
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{
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struct packet_filter_hook *pfh;
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TAILQ_FOREACH(pfh, chain, pfil_chain)
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if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
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TAILQ_REMOVE(chain, pfh, pfil_chain);
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free(pfh, M_IFADDR);
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return (0);
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}
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return (ENOENT);
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}
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/*
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* Stuff that must be initialized for every instance (including the first of
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* course).
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*/
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static void
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vnet_pfil_init(const void *unused __unused)
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{
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LIST_INIT(&V_pfil_head_list);
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PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared");
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}
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/*
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* Called for the removal of each instance.
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*/
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static void
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vnet_pfil_uninit(const void *unused __unused)
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{
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KASSERT(LIST_EMPTY(&V_pfil_head_list),
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("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
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PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
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}
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/*
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* Starting up.
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*
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* VNET_SYSINIT is called for each existing vnet and each new vnet.
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* Make sure the pfil bits are first before any possible subsystem which
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* might piggyback on the SI_SUB_PROTO_PFIL.
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*/
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VNET_SYSINIT(vnet_pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
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vnet_pfil_init, NULL);
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/*
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* Closing up shop. These are done in REVERSE ORDER. Not called on reboot.
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*
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* VNET_SYSUNINIT is called for each exiting vnet as it exits.
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*/
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VNET_SYSUNINIT(vnet_pfil_uninit, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
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vnet_pfil_uninit, NULL);
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