348 lines
8.9 KiB
C
348 lines
8.9 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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__KERNEL_RCSID(0, "$NetBSD: uipc_accf.c,v 1.2 2008/08/06 15:01:23 plunky Exp $");
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#define ACCEPT_FILTER_MOD
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#include "opt_inet.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/lkm.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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#include <sys/once.h>
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static kmutex_t accept_filter_mtx;
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#define ACCEPT_FILTER_LOCK() mutex_spin_enter(&accept_filter_mtx)
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#define ACCEPT_FILTER_UNLOCK() mutex_spin_exit(&accept_filter_mtx);
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#define SOCK_LOCK(so)
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#define SOCK_UNLOCK(so)
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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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/*
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* Names of Accept filter sysctl objects
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*/
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#define ACCFCTL_UNLOADABLE 1 /* Allow module to be unloaded */
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SYSCTL_SETUP(sysctl_net_inet_accf_setup, "sysctl net.inet.accf subtree setup")
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{
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "net", NULL,
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NULL, 0, NULL, 0,
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CTL_NET, CTL_EOL);
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "inet", NULL,
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NULL, 0, NULL, 0,
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CTL_NET, PF_INET, CTL_EOL);
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "accf",
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SYSCTL_DESCR("Accept filters"),
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NULL, 0, NULL, 0,
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CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL);
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
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CTLTYPE_INT, "unloadable",
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SYSCTL_DESCR("Allow unload of accept filters "
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"(not recommended)"),
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NULL, 0, &unloadable, 0,
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CTL_NET, PF_INET, SO_ACCEPTFILTER,
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ACCFCTL_UNLOADABLE, CTL_EOL);
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}
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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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/*
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* Accept filter initialization routine.
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* This should be called only once.
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*/
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static int
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accept_filter_init0(void)
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{
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mutex_init(&accept_filter_mtx, MUTEX_DEFAULT, IPL_NET);
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return 0;
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}
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/*
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* Initialization routine: This can also be replaced with
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* accept_filt_generic_mod_event for attaching new accept filter.
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*/
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void
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accept_filter_init(void)
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{
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static ONCE_DECL(accept_filter_init_once);
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RUN_ONCE(&accept_filter_init_once, accept_filter_init0);
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}
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int
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accept_filt_generic_mod_event(struct lkm_table *lkmtp, 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 LKM_E_LOAD:
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accept_filter_init();
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MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF,
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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 LKM_E_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 LKM_E_STAT:
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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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do_getopt_accept_filter(struct socket *so, struct sockopt *sopt)
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{
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struct accept_filter_arg afa;
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int error;
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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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memset(&afa, 0, sizeof(afa));
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strcpy(afa.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(afa.af_arg, so->so_accf->so_accept_filter_str);
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error = sockopt_set(sopt, &afa, sizeof(afa));
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out:
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SOCK_UNLOCK(so);
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return (error);
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}
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int
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do_setopt_accept_filter(struct socket *so, const struct sockopt *sopt)
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{
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struct accept_filter_arg afa;
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struct accept_filter *afp;
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struct so_accf *newaf;
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int error;
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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_size == 0) {
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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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error = sockopt_get(sopt, &afa, sizeof(afa));
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if (error) {
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return (error);
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}
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afa.af_name[sizeof(afa.af_name)-1] = '\0';
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afa.af_arg[sizeof(afa.af_arg)-1] = '\0';
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afp = accept_filt_get(afa.af_name);
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if (afp == NULL) {
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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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MALLOC(newaf, struct so_accf *, sizeof(*newaf), M_ACCF, M_WAITOK |
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M_ZERO);
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if (afp->accf_create != NULL && afa.af_name[0] != '\0') {
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int len = strlen(afa.af_name) + 1;
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MALLOC(newaf->so_accept_filter_str, char *, len, M_ACCF,
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M_WAITOK);
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strcpy(newaf->so_accept_filter_str, afa.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, afa.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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return (error);
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}
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