176 lines
4.6 KiB
C
176 lines
4.6 KiB
C
/* $FreeBSD$ */
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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/queue.h>
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#include <net/if.h>
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#include <net/pfil.h>
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static void pfil_init __P((struct pfil_head *));
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static int 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 int 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(ph)
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struct pfil_head *ph;
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{
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TAILQ_INIT(&ph->ph_in);
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TAILQ_INIT(&ph->ph_out);
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ph->ph_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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int
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pfil_add_hook(func, flags, ph)
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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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struct pfil_head *ph;
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{
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int err = 0;
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if (ph->ph_init == 0)
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pfil_init(ph);
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if (flags & PFIL_IN)
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err = pfil_list_add(&ph->ph_in, func, flags & ~PFIL_OUT);
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if (err)
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return err;
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if (flags & PFIL_OUT)
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err = pfil_list_add(&ph->ph_out, func, flags & ~PFIL_IN);
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if (err) {
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if (flags & PFIL_IN)
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pfil_list_remove(&ph->ph_in, func);
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return err;
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}
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return 0;
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}
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static int
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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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return ENOMEM;
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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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return 0;
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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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int
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pfil_remove_hook(func, flags, ph)
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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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struct pfil_head *ph;
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{
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int err = 0;
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if (ph->ph_init == 0)
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pfil_init(ph);
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if (flags & PFIL_IN)
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err = pfil_list_remove(&ph->ph_in, func);
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if ((err == 0) && (flags & PFIL_OUT))
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err = pfil_list_remove(&ph->ph_out, func);
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return err;
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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 int
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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 0;
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}
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return ENOENT;
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}
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struct packet_filter_hook *
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pfil_hook_get(flag, ph)
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int flag;
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struct pfil_head *ph;
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{
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if (ph->ph_init != 0)
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switch (flag) {
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case PFIL_IN:
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return (ph->ph_in.tqh_first);
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case PFIL_OUT:
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return (ph->ph_out.tqh_first);
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}
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return NULL;
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}
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