/*-
* Copyright (c) 2000 Paycounter, Inc.
* Copyright (c) 2005 Robert N. M. Watson
* Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
* 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>
__FBSDID("$FreeBSD$");
#define ACCEPT_FILTER_MOD
#include "opt_param.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/queue.h>
static struct mtx accept_filter_mtx;
MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
MTX_DEF);
#define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
#define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
static SLIST_HEAD(, accept_filter) accept_filtlsthd =
SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
static int unloadable = 0;
SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */
SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
"Allow unload of accept filters (not recommended)");
/*
* Must be passed a malloc'd structure so we don't explode if the kld is
* unloaded, we leak the struct on deallocation to deal with this, but if a
* filter is loaded with the same name as a leaked one we re-use the entry.
*/
int
accept_filt_add(struct accept_filter *filt)
{
struct accept_filter *p;
ACCEPT_FILTER_LOCK();
SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
if (strcmp(p->accf_name, filt->accf_name) == 0) {
if (p->accf_callback != NULL) {
ACCEPT_FILTER_UNLOCK();
return (EEXIST);
} else {
p->accf_callback = filt->accf_callback;
ACCEPT_FILTER_UNLOCK();
FREE(filt, M_ACCF);
return (0);
}
}
if (p == NULL)
SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
ACCEPT_FILTER_UNLOCK();
return (0);
}
int
accept_filt_del(char *name)
{
struct accept_filter *p;
p = accept_filt_get(name);
if (p == NULL)
return (ENOENT);
p->accf_callback = NULL;
return (0);
}
struct accept_filter *
accept_filt_get(char *name)
{
struct accept_filter *p;
ACCEPT_FILTER_LOCK();
SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
if (strcmp(p->accf_name, name) == 0)
break;
ACCEPT_FILTER_UNLOCK();
return (p);
}
int
accept_filt_generic_mod_event(module_t mod, int event, void *data)
{
struct accept_filter *p;
struct accept_filter *accfp = (struct accept_filter *) data;
int error;
switch (event) {
case MOD_LOAD:
MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF,
M_WAITOK);
bcopy(accfp, p, sizeof(*p));
error = accept_filt_add(p);
break;
case MOD_UNLOAD:
/*
* Do not support unloading yet. we don't keep track of
* refcounts and unloading an accept filter callback and then
* having it called is a bad thing. A simple fix would be to
* track the refcount in the struct accept_filter.
*/
if (unloadable != 0) {
error = accept_filt_del(accfp->accf_name);
} else
error = EOPNOTSUPP;
break;
case MOD_SHUTDOWN:
error = 0;
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
int
do_getopt_accept_filter(struct socket *so, struct sockopt *sopt)
{
struct accept_filter_arg *afap;
int error;
error = 0;
MALLOC(afap, struct accept_filter_arg *, sizeof(*afap), M_TEMP,
M_WAITOK | M_ZERO);
SOCK_LOCK(so);
if ((so->so_options & SO_ACCEPTCONN) == 0) {
error = EINVAL;
goto out;
}
if ((so->so_options & SO_ACCEPTFILTER) == 0) {
error = EINVAL;
goto out;
}
strcpy(afap->af_name, so->so_accf->so_accept_filter->accf_name);
if (so->so_accf->so_accept_filter_str != NULL)
strcpy(afap->af_arg, so->so_accf->so_accept_filter_str);
out:
SOCK_UNLOCK(so);
if (error == 0)
error = sooptcopyout(sopt, afap, sizeof(*afap));
FREE(afap, M_TEMP);
return (error);
}
int
do_setopt_accept_filter(struct socket *so, struct sockopt *sopt)
{
struct accept_filter_arg *afap;
struct accept_filter *afp;
struct so_accf *newaf;
int error = 0;
/*
* Handle the simple delete case first.
*/
if (sopt == NULL || sopt->sopt_val == NULL) {
SOCK_LOCK(so);
if ((so->so_options & SO_ACCEPTCONN) == 0) {
SOCK_UNLOCK(so);
return (EINVAL);
}
if (so->so_accf != NULL) {
struct so_accf *af = so->so_accf;
if (af->so_accept_filter != NULL &&
af->so_accept_filter->accf_destroy != NULL) {
af->so_accept_filter->accf_destroy(so);
}
if (af->so_accept_filter_str != NULL)
FREE(af->so_accept_filter_str, M_ACCF);
FREE(af, M_ACCF);
so->so_accf = NULL;
}
so->so_options &= ~SO_ACCEPTFILTER;
SOCK_UNLOCK(so);
return (0);
}
/*
* Pre-allocate any memory we may need later to avoid blocking at
* untimely moments. This does not optimize for invalid arguments.
*/
MALLOC(afap, struct accept_filter_arg *, sizeof(*afap), M_TEMP,
M_WAITOK);
error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
afap->af_name[sizeof(afap->af_name)-1] = '\0';
afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
if (error) {
FREE(afap, M_TEMP);
return (error);
}
afp = accept_filt_get(afap->af_name);
if (afp == NULL) {
FREE(afap, M_TEMP);
return (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.
*/
MALLOC(newaf, struct so_accf *, sizeof(*newaf), M_ACCF, M_WAITOK |
M_ZERO);
if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
int len = strlen(afap->af_name) + 1;
MALLOC(newaf->so_accept_filter_str, char *, len, M_ACCF,
M_WAITOK);
strcpy(newaf->so_accept_filter_str, afap->af_name);
}
/*
* Require a listen socket; don't try to replace an existing filter
* without first removing it.
*/
SOCK_LOCK(so);
if (((so->so_options & SO_ACCEPTCONN) == 0) ||
(so->so_accf != NULL)) {
error = EINVAL;
goto out;
}
/*
* Invoke the accf_create() method of the filter if required. The
* socket mutex is held over this call, so create methods for filters
* can't block.
*/
if (afp->accf_create != NULL) {
newaf->so_accept_filter_arg =
afp->accf_create(so, afap->af_arg);
if (newaf->so_accept_filter_arg == NULL) {
error = EINVAL;
goto out;
}
}
newaf->so_accept_filter = afp;
so->so_accf = newaf;
so->so_options |= SO_ACCEPTFILTER;
newaf = NULL;
out:
SOCK_UNLOCK(so);
if (newaf != NULL) {
if (newaf->so_accept_filter_str != NULL)
FREE(newaf->so_accept_filter_str, M_ACCF);
FREE(newaf, M_ACCF);
}
if (afap != NULL)
FREE(afap, M_TEMP);
return (error);
}
