2 * Copyright (c) 2000 Paycounter, Inc.
3 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #define ACCEPT_FILTER_MOD
33 #include "opt_param.h"
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/domain.h>
37 #include <sys/kernel.h>
39 #include <sys/malloc.h>
41 #include <sys/module.h>
42 #include <sys/mutex.h>
43 #include <sys/protosw.h>
44 #include <sys/sysctl.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
47 #include <sys/queue.h>
49 static struct mtx accept_filter_mtx;
50 MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
52 #define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
53 #define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
55 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
56 SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
58 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
60 static int unloadable = 0;
62 SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */
63 SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
64 SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
65 "Allow unload of accept filters (not recommended)");
68 * Must be passed a malloc'd structure so we don't explode if the kld is
69 * unloaded, we leak the struct on deallocation to deal with this, but if a
70 * filter is loaded with the same name as a leaked one we re-use the entry.
73 accept_filt_add(struct accept_filter *filt)
75 struct accept_filter *p;
78 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
79 if (strcmp(p->accf_name, filt->accf_name) == 0) {
80 if (p->accf_callback != NULL) {
81 ACCEPT_FILTER_UNLOCK();
84 p->accf_callback = filt->accf_callback;
85 ACCEPT_FILTER_UNLOCK();
92 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
93 ACCEPT_FILTER_UNLOCK();
98 accept_filt_del(char *name)
100 struct accept_filter *p;
102 p = accept_filt_get(name);
106 p->accf_callback = NULL;
110 struct accept_filter *
111 accept_filt_get(char *name)
113 struct accept_filter *p;
115 ACCEPT_FILTER_LOCK();
116 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
117 if (strcmp(p->accf_name, name) == 0)
119 ACCEPT_FILTER_UNLOCK();
125 accept_filt_generic_mod_event(module_t mod, int event, void *data)
127 struct accept_filter *p;
128 struct accept_filter *accfp = (struct accept_filter *) data;
133 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF,
135 bcopy(accfp, p, sizeof(*p));
136 error = accept_filt_add(p);
141 * Do not support unloading yet. we don't keep track of
142 * refcounts and unloading an accept filter callback and then
143 * having it called is a bad thing. A simple fix would be to
144 * track the refcount in the struct accept_filter.
146 if (unloadable != 0) {
147 error = accept_filt_del(accfp->accf_name);
165 do_setopt_accept_filter(struct socket *so, struct sockopt *sopt)
167 struct accept_filter_arg *afap;
168 struct accept_filter *afp;
169 struct so_accf *newaf;
176 * XXXRW: Configuring accept filters should be an atomic test-and-set
177 * operation to prevent races during setup and attach. There may be
178 * more general issues of racing and ordering here that are not yet
179 * addressed by locking.
181 /* do not set/remove accept filters on non listen sockets */
183 if ((so->so_options & SO_ACCEPTCONN) == 0) {
188 /* removing the filter */
190 if (so->so_accf != NULL) {
191 struct so_accf *af = so->so_accf;
192 if (af->so_accept_filter != NULL &&
193 af->so_accept_filter->accf_destroy != NULL) {
194 af->so_accept_filter->accf_destroy(so);
196 if (af->so_accept_filter_str != NULL) {
197 FREE(af->so_accept_filter_str, M_ACCF);
202 so->so_options &= ~SO_ACCEPTFILTER;
211 * Do memory allocation, copyin, and filter lookup now while we're
212 * not holding any locks. Avoids sleeping with a mutex, as well as
213 * introducing a lock order between accept filter locks and socket
216 MALLOC(afap, struct accept_filter_arg *, sizeof(*afap), M_TEMP,
218 /* don't put large objects on the kernel stack */
219 error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
220 afap->af_name[sizeof(afap->af_name)-1] = '\0';
221 afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
226 afp = accept_filt_get(afap->af_name);
233 * Allocate the new accept filter instance storage. We may have to
234 * free it again later if we fail to attach it. If attached
235 * properly, 'newaf' is NULLed to avoid a free() while in use.
237 MALLOC(newaf, struct so_accf *, sizeof(*newaf), M_ACCF, M_WAITOK |
239 if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
240 int len = strlen(afap->af_name) + 1;
241 MALLOC(newaf->so_accept_filter_str, char *, len, M_ACCF,
243 strcpy(newaf->so_accept_filter_str, afap->af_name);
247 /* must remove previous filter first */
248 if (so->so_accf != NULL) {
253 * Invoke the accf_create() method of the filter if required.
254 * XXXRW: the socket mutex is held over this call, so the create
255 * method cannot block. This may be something we have to change, but
256 * it would require addressing possible races.
258 if (afp->accf_create != NULL) {
259 newaf->so_accept_filter_arg =
260 afp->accf_create(so, afap->af_arg);
261 if (newaf->so_accept_filter_arg == NULL) {
266 newaf->so_accept_filter = afp;
268 so->so_options |= SO_ACCEPTFILTER;
273 if (newaf->so_accept_filter_str != NULL)
274 FREE(newaf->so_accept_filter_str, M_ACCF);