2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2000 Paycounter, Inc.
5 * Copyright (c) 2005 Robert N. M. Watson
6 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #define ACCEPT_FILTER_MOD
36 #include "opt_param.h"
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/domain.h>
40 #include <sys/kernel.h>
42 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/mutex.h>
46 #include <sys/protosw.h>
47 #include <sys/sysctl.h>
48 #include <sys/socket.h>
49 #include <sys/socketvar.h>
50 #include <sys/queue.h>
52 static struct mtx accept_filter_mtx;
53 MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
55 #define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
56 #define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
58 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
59 SLIST_HEAD_INITIALIZER(accept_filtlsthd);
61 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
63 static int unloadable = 0;
65 SYSCTL_NODE(_net, OID_AUTO, accf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
67 SYSCTL_INT(_net_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
68 "Allow unload of accept filters (not recommended)");
71 * Must be passed a malloc'd structure so we don't explode if the kld is
72 * unloaded, we leak the struct on deallocation to deal with this, but if a
73 * filter is loaded with the same name as a leaked one we re-use the entry.
76 accept_filt_add(struct accept_filter *filt)
78 struct accept_filter *p;
81 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
82 if (strcmp(p->accf_name, filt->accf_name) == 0) {
83 if (p->accf_callback != NULL) {
84 ACCEPT_FILTER_UNLOCK();
87 p->accf_callback = filt->accf_callback;
88 ACCEPT_FILTER_UNLOCK();
95 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
96 ACCEPT_FILTER_UNLOCK();
101 accept_filt_del(char *name)
103 struct accept_filter *p;
105 p = accept_filt_get(name);
109 p->accf_callback = NULL;
113 struct accept_filter *
114 accept_filt_get(char *name)
116 struct accept_filter *p;
118 ACCEPT_FILTER_LOCK();
119 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
120 if (strcmp(p->accf_name, name) == 0)
122 ACCEPT_FILTER_UNLOCK();
128 accept_filt_generic_mod_event(module_t mod, int event, void *data)
130 struct accept_filter *p;
131 struct accept_filter *accfp = (struct accept_filter *) data;
136 p = malloc(sizeof(*p), M_ACCF, M_WAITOK);
137 bcopy(accfp, p, sizeof(*p));
138 error = accept_filt_add(p);
143 * Do not support unloading yet. we don't keep track of
144 * refcounts and unloading an accept filter callback and then
145 * having it called is a bad thing. A simple fix would be to
146 * track the refcount in the struct accept_filter.
148 if (unloadable != 0) {
149 error = accept_filt_del(accfp->accf_name);
167 accept_filt_getopt(struct socket *so, struct sockopt *sopt)
169 struct accept_filter_arg *afap;
173 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK | M_ZERO);
175 if ((so->so_options & SO_ACCEPTCONN) == 0) {
179 if (so->sol_accept_filter == NULL) {
183 strcpy(afap->af_name, so->sol_accept_filter->accf_name);
184 if (so->sol_accept_filter_str != NULL)
185 strcpy(afap->af_arg, so->sol_accept_filter_str);
189 error = sooptcopyout(sopt, afap, sizeof(*afap));
195 accept_filt_setopt(struct socket *so, struct sockopt *sopt)
197 struct accept_filter_arg *afap;
198 struct accept_filter *afp;
199 char *accept_filter_str = NULL;
200 void *accept_filter_arg = NULL;
204 * Handle the simple delete case first.
206 if (sopt == NULL || sopt->sopt_val == NULL) {
207 struct socket *sp, *sp1;
211 if ((so->so_options & SO_ACCEPTCONN) == 0) {
215 if (so->sol_accept_filter == NULL) {
219 if (so->sol_accept_filter->accf_destroy != NULL)
220 so->sol_accept_filter->accf_destroy(so);
221 if (so->sol_accept_filter_str != NULL)
222 free(so->sol_accept_filter_str, M_ACCF);
223 so->sol_accept_filter = NULL;
224 so->sol_accept_filter_arg = NULL;
225 so->sol_accept_filter_str = NULL;
226 so->so_options &= ~SO_ACCEPTFILTER;
229 * Move from incomplete queue to complete only those
230 * connections, that are blocked by us.
233 TAILQ_FOREACH_SAFE(sp, &so->sol_incomp, so_list, sp1) {
235 if (sp->so_options & SO_ACCEPTFILTER) {
236 TAILQ_REMOVE(&so->sol_incomp, sp, so_list);
237 TAILQ_INSERT_TAIL(&so->sol_comp, sp, so_list);
238 sp->so_qstate = SQ_COMP;
239 sp->so_options &= ~SO_ACCEPTFILTER;
247 solisten_wakeup(so); /* unlocks */
254 * Pre-allocate any memory we may need later to avoid blocking at
255 * untimely moments. This does not optimize for invalid arguments.
257 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK);
258 error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
259 afap->af_name[sizeof(afap->af_name)-1] = '\0';
260 afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
265 afp = accept_filt_get(afap->af_name);
270 if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
271 size_t len = strlen(afap->af_name) + 1;
272 accept_filter_str = malloc(len, M_ACCF, M_WAITOK);
273 strcpy(accept_filter_str, afap->af_name);
277 * Require a listen socket; don't try to replace an existing filter
278 * without first removing it.
281 if ((so->so_options & SO_ACCEPTCONN) == 0 ||
282 so->sol_accept_filter != NULL) {
288 * Invoke the accf_create() method of the filter if required. The
289 * socket mutex is held over this call, so create methods for filters
292 if (afp->accf_create != NULL) {
293 accept_filter_arg = afp->accf_create(so, afap->af_arg);
294 if (accept_filter_arg == NULL) {
299 so->sol_accept_filter = afp;
300 so->sol_accept_filter_arg = accept_filter_arg;
301 so->sol_accept_filter_str = accept_filter_str;
302 so->so_options |= SO_ACCEPTFILTER;
305 if (accept_filter_str != NULL)
306 free(accept_filter_str, M_ACCF);