293 lines
7.7 KiB
C
293 lines
7.7 KiB
C
/*-
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* Copyright (c) 2000 Paycounter, Inc.
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* Copyright (c) 2005 Robert N. M. Watson
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* Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, 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/cdefs.h>
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__FBSDID("$FreeBSD$");
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#define ACCEPT_FILTER_MOD
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#include "opt_param.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/domain.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/protosw.h>
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#include <sys/sysctl.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/queue.h>
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static struct mtx accept_filter_mtx;
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MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
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MTX_DEF);
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#define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
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#define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
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static SLIST_HEAD(, accept_filter) accept_filtlsthd =
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SLIST_HEAD_INITIALIZER(accept_filtlsthd);
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MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
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static int unloadable = 0;
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SYSCTL_NODE(_net, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
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SYSCTL_INT(_net_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
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"Allow unload of accept filters (not recommended)");
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/*
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* Must be passed a malloc'd structure so we don't explode if the kld is
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* unloaded, we leak the struct on deallocation to deal with this, but if a
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* filter is loaded with the same name as a leaked one we re-use the entry.
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*/
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int
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accept_filt_add(struct accept_filter *filt)
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{
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struct accept_filter *p;
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ACCEPT_FILTER_LOCK();
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SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
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if (strcmp(p->accf_name, filt->accf_name) == 0) {
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if (p->accf_callback != NULL) {
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ACCEPT_FILTER_UNLOCK();
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return (EEXIST);
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} else {
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p->accf_callback = filt->accf_callback;
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ACCEPT_FILTER_UNLOCK();
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free(filt, M_ACCF);
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return (0);
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}
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}
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if (p == NULL)
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SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
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ACCEPT_FILTER_UNLOCK();
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return (0);
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}
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int
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accept_filt_del(char *name)
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{
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struct accept_filter *p;
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p = accept_filt_get(name);
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if (p == NULL)
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return (ENOENT);
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p->accf_callback = NULL;
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return (0);
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}
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struct accept_filter *
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accept_filt_get(char *name)
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{
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struct accept_filter *p;
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ACCEPT_FILTER_LOCK();
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SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
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if (strcmp(p->accf_name, name) == 0)
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break;
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ACCEPT_FILTER_UNLOCK();
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return (p);
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}
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int
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accept_filt_generic_mod_event(module_t mod, int event, void *data)
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{
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struct accept_filter *p;
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struct accept_filter *accfp = (struct accept_filter *) data;
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int error;
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switch (event) {
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case MOD_LOAD:
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p = malloc(sizeof(*p), M_ACCF, M_WAITOK);
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bcopy(accfp, p, sizeof(*p));
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error = accept_filt_add(p);
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break;
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case MOD_UNLOAD:
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/*
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* Do not support unloading yet. we don't keep track of
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* refcounts and unloading an accept filter callback and then
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* having it called is a bad thing. A simple fix would be to
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* track the refcount in the struct accept_filter.
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*/
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if (unloadable != 0) {
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error = accept_filt_del(accfp->accf_name);
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} else
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error = EOPNOTSUPP;
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break;
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case MOD_SHUTDOWN:
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error = 0;
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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int
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accept_filt_getopt(struct socket *so, struct sockopt *sopt)
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{
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struct accept_filter_arg *afap;
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int error;
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error = 0;
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afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK | M_ZERO);
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SOCK_LOCK(so);
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if ((so->so_options & SO_ACCEPTCONN) == 0) {
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error = EINVAL;
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goto out;
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}
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if ((so->so_options & SO_ACCEPTFILTER) == 0) {
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error = EINVAL;
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goto out;
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}
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strcpy(afap->af_name, so->so_accf->so_accept_filter->accf_name);
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if (so->so_accf->so_accept_filter_str != NULL)
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strcpy(afap->af_arg, so->so_accf->so_accept_filter_str);
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out:
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SOCK_UNLOCK(so);
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if (error == 0)
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error = sooptcopyout(sopt, afap, sizeof(*afap));
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free(afap, M_TEMP);
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return (error);
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}
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int
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accept_filt_setopt(struct socket *so, struct sockopt *sopt)
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{
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struct accept_filter_arg *afap;
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struct accept_filter *afp;
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struct so_accf *newaf;
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int error = 0;
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/*
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* Handle the simple delete case first.
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*/
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if (sopt == NULL || sopt->sopt_val == NULL) {
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SOCK_LOCK(so);
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if ((so->so_options & SO_ACCEPTCONN) == 0) {
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SOCK_UNLOCK(so);
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return (EINVAL);
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}
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if (so->so_accf != NULL) {
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struct so_accf *af = so->so_accf;
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if (af->so_accept_filter != NULL &&
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af->so_accept_filter->accf_destroy != NULL) {
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af->so_accept_filter->accf_destroy(so);
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}
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if (af->so_accept_filter_str != NULL)
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free(af->so_accept_filter_str, M_ACCF);
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free(af, M_ACCF);
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so->so_accf = NULL;
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}
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so->so_options &= ~SO_ACCEPTFILTER;
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SOCK_UNLOCK(so);
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return (0);
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}
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/*
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* Pre-allocate any memory we may need later to avoid blocking at
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* untimely moments. This does not optimize for invalid arguments.
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*/
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afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK);
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error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
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afap->af_name[sizeof(afap->af_name)-1] = '\0';
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afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
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if (error) {
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free(afap, M_TEMP);
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return (error);
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}
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afp = accept_filt_get(afap->af_name);
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if (afp == NULL) {
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free(afap, M_TEMP);
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return (ENOENT);
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}
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/*
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* Allocate the new accept filter instance storage. We may
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* have to free it again later if we fail to attach it. If
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* attached properly, 'newaf' is NULLed to avoid a free()
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* while in use.
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*/
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newaf = malloc(sizeof(*newaf), M_ACCF, M_WAITOK | M_ZERO);
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if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
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size_t len = strlen(afap->af_name) + 1;
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newaf->so_accept_filter_str = malloc(len, M_ACCF, M_WAITOK);
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strcpy(newaf->so_accept_filter_str, afap->af_name);
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}
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/*
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* Require a listen socket; don't try to replace an existing filter
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* without first removing it.
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*/
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SOCK_LOCK(so);
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if (((so->so_options & SO_ACCEPTCONN) == 0) ||
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(so->so_accf != NULL)) {
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error = EINVAL;
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goto out;
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}
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/*
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* Invoke the accf_create() method of the filter if required. The
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* socket mutex is held over this call, so create methods for filters
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* can't block.
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*/
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if (afp->accf_create != NULL) {
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newaf->so_accept_filter_arg =
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afp->accf_create(so, afap->af_arg);
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if (newaf->so_accept_filter_arg == NULL) {
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error = EINVAL;
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goto out;
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}
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}
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newaf->so_accept_filter = afp;
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so->so_accf = newaf;
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so->so_options |= SO_ACCEPTFILTER;
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newaf = NULL;
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out:
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SOCK_UNLOCK(so);
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if (newaf != NULL) {
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if (newaf->so_accept_filter_str != NULL)
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free(newaf->so_accept_filter_str, M_ACCF);
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free(newaf, M_ACCF);
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}
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if (afap != NULL)
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free(afap, M_TEMP);
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return (error);
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}
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