/* $NetBSD: uipc_accf.c,v 1.16 2024/12/06 18:44:00 riastradh Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software developed for The NetBSD Foundation
* by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*-
* Copyright (c) 2000 Paycounter, Inc.
* Copyright (c) 2005 Robert N. M. Watson
* Author: Alfred Perlstein <
[email protected]>, <
[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uipc_accf.c,v 1.16 2024/12/06 18:44:00 riastradh Exp $");
#define ACCEPT_FILTER_MOD
#include <sys/param.h>
#include <sys/types.h>
#include <sys/atomic.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/once.h>
#include <sys/protosw.h>
#include <sys/queue.h>
#include <sys/rwlock.h>
#include <sys/sdt.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
static krwlock_t accept_filter_lock;
static LIST_HEAD(, accept_filter) accept_filtlsthd =
LIST_HEAD_INITIALIZER(&accept_filtlsthd);
/*
* Names of Accept filter sysctl objects
*/
static struct sysctllog *ctllog;
static void
sysctl_net_inet_accf_setup(void)
{
sysctl_createv(&ctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "inet", NULL,
NULL, 0, NULL, 0,
CTL_NET, PF_INET, CTL_EOL);
sysctl_createv(&ctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "accf",
SYSCTL_DESCR("Accept filters"),
NULL, 0, NULL, 0,
CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL);
}
int
accept_filt_add(struct accept_filter *filt)
{
struct accept_filter *p;
accept_filter_init();
rw_enter(&accept_filter_lock, RW_WRITER);
LIST_FOREACH(p, &accept_filtlsthd, accf_next) {
if (strcmp(p->accf_name, filt->accf_name) == 0) {
rw_exit(&accept_filter_lock);
return SET_ERROR(EEXIST);
}
}
LIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
rw_exit(&accept_filter_lock);
return 0;
}
int
accept_filt_del(struct accept_filter *p)
{
rw_enter(&accept_filter_lock, RW_WRITER);
if (p->accf_refcnt != 0) {
rw_exit(&accept_filter_lock);
return SET_ERROR(EBUSY);
}
LIST_REMOVE(p, accf_next);
rw_exit(&accept_filter_lock);
return 0;
}
struct accept_filter *
accept_filt_get(char *name)
{
struct accept_filter *p;
char buf[32];
u_int gen;
do {
rw_enter(&accept_filter_lock, RW_READER);
LIST_FOREACH(p, &accept_filtlsthd, accf_next) {
if (strcmp(p->accf_name, name) == 0) {
atomic_inc_uint(&p->accf_refcnt);
break;
}
}
rw_exit(&accept_filter_lock);
if (p != NULL) {
break;
}
/* Try to autoload a module to satisfy the request. */
strcpy(buf, "accf_");
strlcat(buf, name, sizeof(buf));
gen = module_gen;
(void)module_autoload(buf, MODULE_CLASS_ANY);
} while (gen != module_gen);
return p;
}
/*
* Accept filter initialization routine.
* This should be called only once.
*/
static int
accept_filter_init0(void)
{
rw_init(&accept_filter_lock);
sysctl_net_inet_accf_setup();
return 0;
}
/*
* Initialization routine: This can also be replaced with
* accept_filt_generic_mod_event for attaching new accept filter.
*/
void
accept_filter_init(void)
{
static ONCE_DECL(accept_filter_init_once);
RUN_ONCE(&accept_filter_init_once, accept_filter_init0);
}
int
accept_filt_getopt(struct socket *so, struct sockopt *sopt)
{
struct accept_filter_arg afa;
int error;
KASSERT(solocked(so));
if ((so->so_options & SO_ACCEPTCONN) == 0) {
error = SET_ERROR(EINVAL);
goto out;
}
if ((so->so_options & SO_ACCEPTFILTER) == 0) {
error = SET_ERROR(EINVAL);
goto out;
}
memset(&afa, 0, sizeof(afa));
strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name);
if (so->so_accf->so_accept_filter_str != NULL)
strcpy(afa.af_arg, so->so_accf->so_accept_filter_str);
error = sockopt_set(sopt, &afa, sizeof(afa));
out:
return error;
}
/*
* Simple delete case, with socket locked.
*/
int
accept_filt_clear(struct socket *so)
{
struct accept_filter_arg afa;
struct accept_filter *afp;
struct socket *so2, *next;
struct so_accf *af;
KASSERT(solocked(so));
if ((so->so_options & SO_ACCEPTCONN) == 0) {
return SET_ERROR(EINVAL);
}
if (so->so_accf != NULL) {
/* Break in-flight processing. */
for (so2 = TAILQ_FIRST(&so->so_q0); so2 != NULL; so2 = next) {
next = TAILQ_NEXT(so2, so_qe);
if (so2->so_upcall == NULL) {
continue;
}
so2->so_upcall = NULL;
so2->so_upcallarg = NULL;
so2->so_options &= ~SO_ACCEPTFILTER;
so2->so_rcv.sb_flags &= ~SB_UPCALL;
soisconnected(so2);
}
af = so->so_accf;
afp = af->so_accept_filter;
if (afp != NULL && afp->accf_destroy != NULL) {
(*afp->accf_destroy)(so);
}
if (af->so_accept_filter_str != NULL) {
kmem_free(af->so_accept_filter_str,
sizeof(afa.af_name));
}
kmem_free(af, sizeof(*af));
so->so_accf = NULL;
atomic_dec_uint(&afp->accf_refcnt);
}
so->so_options &= ~SO_ACCEPTFILTER;
return 0;
}
/*
* setsockopt() for accept filters. Called with the socket unlocked,
* will always return it locked.
*/
int
accept_filt_setopt(struct socket *so, const struct sockopt *sopt)
{
struct accept_filter_arg afa;
struct accept_filter *afp;
struct so_accf *newaf;
int error;
accept_filter_init();
if (sopt == NULL || sopt->sopt_size == 0) {
solock(so);
return accept_filt_clear(so);
}
/*
* Pre-allocate any memory we may need later to avoid blocking at
* untimely moments. This does not optimize for invalid arguments.
*/
error = sockopt_get(sopt, &afa, sizeof(afa));
if (error) {
solock(so);
return error;
}
afa.af_name[sizeof(afa.af_name)-1] = '\0';
afa.af_arg[sizeof(afa.af_arg)-1] = '\0';
afp = accept_filt_get(afa.af_name);
if (afp == NULL) {
solock(so);
return SET_ERROR(ENOENT);
}
/*
* Allocate the new accept filter instance storage. We may
* have to free it again later if we fail to attach it. If
* attached properly, 'newaf' is NULLed to avoid a free()
* while in use.
*/
newaf = kmem_zalloc(sizeof(*newaf), KM_SLEEP);
if (afp->accf_create != NULL && afa.af_name[0] != '\0') {
/*
* FreeBSD did a variable-size allocation here
* with the actual string length from afa.af_name
* but it is so short, why bother tracking it?
* XXX as others have noted, this is an API mistake;
* XXX accept_filter_arg should have a mandatory namelen.
* XXX (but it's a bit too late to fix that now)
*/
newaf->so_accept_filter_str =
kmem_alloc(sizeof(afa.af_name), KM_SLEEP);
strcpy(newaf->so_accept_filter_str, afa.af_name);
}
/*
* Require a listen socket; don't try to replace an existing filter
* without first removing it.
*/
solock(so);
if ((so->so_options & SO_ACCEPTCONN) == 0 || so->so_accf != NULL) {
error = SET_ERROR(EINVAL);
goto out;
}
/*
* Invoke the accf_create() method of the filter if required. The
* socket lock is held over this call, so create methods for filters
* shouldn't block.
*/
if (afp->accf_create != NULL) {
newaf->so_accept_filter_arg =
(*afp->accf_create)(so, afa.af_arg);
if (newaf->so_accept_filter_arg == NULL) {
error = SET_ERROR(EINVAL);
goto out;
}
}
newaf->so_accept_filter = afp;
so->so_accf = newaf;
so->so_options |= SO_ACCEPTFILTER;
newaf = NULL;
out:
if (newaf != NULL) {
if (newaf->so_accept_filter_str != NULL)
kmem_free(newaf->so_accept_filter_str,
sizeof(afa.af_name));
kmem_free(newaf, sizeof(*newaf));
atomic_dec_uint(&afp->accf_refcnt);
}
return error;
}
