45159fa631
change pfil_add_hook to put output filters at the tail of the queue, while continuing to place input filters at the head of the queue. update the two users of these functions, and document these changes. fixes PR#4593.
170 lines
4.5 KiB
C
170 lines
4.5 KiB
C
/* $NetBSD: pfil.c,v 1.7 1998/03/19 15:45:30 mrg 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/errno.h>
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#include <sys/malloc.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/proc.h>
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#include <sys/queue.h>
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#include <net/if.h>
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#include <net/pfil.h>
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typedef TAILQ_HEAD(, packet_filter_hook) pfil_list_t;
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pfil_list_t pfil_in_list;
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pfil_list_t pfil_out_list;
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static int done_pfil_init;
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static void pfil_init __P((void));
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static void pfil_list_add(pfil_list_t *,
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int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)), int);
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static void pfil_list_remove(pfil_list_t,
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int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)));
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static void
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pfil_init()
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{
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TAILQ_INIT(&pfil_in_list);
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TAILQ_INIT(&pfil_out_list);
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done_pfil_init = 1;
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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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void
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pfil_add_hook(func, flags)
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int (*func) __P((void *, int, struct ifnet *, int,
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struct mbuf **));
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int flags;
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{
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if (done_pfil_init == 0)
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pfil_init();
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if (flags & PFIL_IN)
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pfil_list_add(&pfil_in_list, func, flags);
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if (flags & PFIL_OUT)
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pfil_list_add(&pfil_out_list, func, flags);
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}
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static void
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pfil_list_add(list, func, flags)
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pfil_list_t *list;
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int (*func) __P((void *, int, struct ifnet *, int,
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struct mbuf **));
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int flags;
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{
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struct packet_filter_hook *pfh;
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pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
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flags & PFIL_WAITOK ? M_WAITOK : M_NOWAIT);
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if (pfh == NULL)
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panic("no memory for packet filter hook");
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pfh->pfil_func = func;
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/*
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* insert the input list in reverse order of the output list
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* so that 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(list, pfh, pfil_link);
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else
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TAILQ_INSERT_TAIL(list, pfh, pfil_link);
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}
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/*
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* pfil_remove_hook removes a specific function from the packet filter
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* hook list.
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*/
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void
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pfil_remove_hook(func, flags)
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int (*func) __P((void *, int, struct ifnet *, int,
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struct mbuf **));
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int flags;
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{
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if (done_pfil_init == 0)
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pfil_init();
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if (flags & PFIL_IN)
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pfil_list_remove(pfil_in_list, func);
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if (flags & PFIL_OUT)
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pfil_list_remove(pfil_out_list, func);
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}
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/*
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* pfil_list_remove is an internal function that takes a function off the
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* specified list.
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*/
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static void
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pfil_list_remove(list, func)
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pfil_list_t list;
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int (*func) __P((void *, int, struct ifnet *, int,
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struct mbuf **));
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{
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struct packet_filter_hook *pfh;
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for (pfh = list.tqh_first; pfh; pfh = pfh->pfil_link.tqe_next)
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if (pfh->pfil_func == func) {
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TAILQ_REMOVE(&list, pfh, pfil_link);
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free(pfh, M_IFADDR);
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return;
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}
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printf("pfil_list_remove: no function on list\n");
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#ifdef DIAGNOSTIC
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panic("pfil_list_remove");
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#endif
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}
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struct packet_filter_hook *
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pfil_hook_get(flag)
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int flag;
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{
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if (done_pfil_init)
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switch (flag) {
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case PFIL_IN:
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return (pfil_in_list.tqh_first);
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case PFIL_OUT:
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return (pfil_out_list.tqh_first);
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}
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return NULL;
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}
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