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, 0, "Accept filters");
66 SYSCTL_INT(_net_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
67 "Allow unload of accept filters (not recommended)");
70 * Must be passed a malloc'd structure so we don't explode if the kld is
71 * unloaded, we leak the struct on deallocation to deal with this, but if a
72 * filter is loaded with the same name as a leaked one we re-use the entry.
75 accept_filt_add(struct accept_filter *filt)
77 struct accept_filter *p;
80 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
81 if (strcmp(p->accf_name, filt->accf_name) == 0) {
82 if (p->accf_callback != NULL) {
83 ACCEPT_FILTER_UNLOCK();
86 p->accf_callback = filt->accf_callback;
87 ACCEPT_FILTER_UNLOCK();
94 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
95 ACCEPT_FILTER_UNLOCK();
100 accept_filt_del(char *name)
102 struct accept_filter *p;
104 p = accept_filt_get(name);
108 p->accf_callback = NULL;
112 struct accept_filter *
113 accept_filt_get(char *name)
115 struct accept_filter *p;
117 ACCEPT_FILTER_LOCK();
118 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
119 if (strcmp(p->accf_name, name) == 0)
121 ACCEPT_FILTER_UNLOCK();
127 accept_filt_generic_mod_event(module_t mod, int event, void *data)
129 struct accept_filter *p;
130 struct accept_filter *accfp = (struct accept_filter *) data;
135 p = malloc(sizeof(*p), M_ACCF, M_WAITOK);
136 bcopy(accfp, p, sizeof(*p));
137 error = accept_filt_add(p);
142 * Do not support unloading yet. we don't keep track of
143 * refcounts and unloading an accept filter callback and then
144 * having it called is a bad thing. A simple fix would be to
145 * track the refcount in the struct accept_filter.
147 if (unloadable != 0) {
148 error = accept_filt_del(accfp->accf_name);
166 accept_filt_getopt(struct socket *so, struct sockopt *sopt)
168 struct accept_filter_arg *afap;
172 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK | M_ZERO);
174 if ((so->so_options & SO_ACCEPTCONN) == 0) {
178 if (so->sol_accept_filter == NULL) {
182 strcpy(afap->af_name, so->sol_accept_filter->accf_name);
183 if (so->sol_accept_filter_str != NULL)
184 strcpy(afap->af_arg, so->sol_accept_filter_str);
188 error = sooptcopyout(sopt, afap, sizeof(*afap));
194 accept_filt_setopt(struct socket *so, struct sockopt *sopt)
196 struct accept_filter_arg *afap;
197 struct accept_filter *afp;
198 char *accept_filter_str = NULL;
199 void *accept_filter_arg = NULL;
203 * Handle the simple delete case first.
205 if (sopt == NULL || sopt->sopt_val == NULL) {
206 struct socket *sp, *sp1;
210 if ((so->so_options & SO_ACCEPTCONN) == 0) {
214 if (so->sol_accept_filter == NULL) {
218 if (so->sol_accept_filter->accf_destroy != NULL)
219 so->sol_accept_filter->accf_destroy(so);
220 if (so->sol_accept_filter_str != NULL)
221 free(so->sol_accept_filter_str, M_ACCF);
222 so->sol_accept_filter = NULL;
223 so->sol_accept_filter_arg = NULL;
224 so->sol_accept_filter_str = NULL;
225 so->so_options &= ~SO_ACCEPTFILTER;
228 * Move from incomplete queue to complete only those
229 * connections, that are blocked by us.
232 TAILQ_FOREACH_SAFE(sp, &so->sol_incomp, so_list, sp1) {
234 if (sp->so_options & SO_ACCEPTFILTER) {
235 TAILQ_REMOVE(&so->sol_incomp, sp, so_list);
236 TAILQ_INSERT_TAIL(&so->sol_comp, sp, so_list);
237 sp->so_qstate = SQ_COMP;
238 sp->so_options &= ~SO_ACCEPTFILTER;
246 solisten_wakeup(so); /* unlocks */
253 * Pre-allocate any memory we may need later to avoid blocking at
254 * untimely moments. This does not optimize for invalid arguments.
256 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK);
257 error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
258 afap->af_name[sizeof(afap->af_name)-1] = '\0';
259 afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
264 afp = accept_filt_get(afap->af_name);
269 if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
270 size_t len = strlen(afap->af_name) + 1;
271 accept_filter_str = malloc(len, M_ACCF, M_WAITOK);
272 strcpy(accept_filter_str, afap->af_name);
276 * Require a listen socket; don't try to replace an existing filter
277 * without first removing it.
280 if ((so->so_options & SO_ACCEPTCONN) == 0 ||
281 so->sol_accept_filter != NULL) {
287 * Invoke the accf_create() method of the filter if required. The
288 * socket mutex is held over this call, so create methods for filters
291 if (afp->accf_create != NULL) {
292 accept_filter_arg = afp->accf_create(so, afap->af_arg);
293 if (accept_filter_arg == NULL) {
298 so->sol_accept_filter = afp;
299 so->sol_accept_filter_arg = accept_filter_arg;
300 so->sol_accept_filter_str = accept_filter_str;
301 so->so_options |= SO_ACCEPTFILTER;
304 if (accept_filter_str != NULL)
305 free(accept_filter_str, M_ACCF);