2 * SPDX-License-Identifier: BSD-2-Clause
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 #define ACCEPT_FILTER_MOD
34 #include "opt_param.h"
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/domain.h>
38 #include <sys/kernel.h>
40 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/protosw.h>
45 #include <sys/sysctl.h>
46 #include <sys/socket.h>
47 #include <sys/socketvar.h>
48 #include <sys/queue.h>
50 static struct mtx accept_filter_mtx;
51 MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx",
53 #define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx)
54 #define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx)
56 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
57 SLIST_HEAD_INITIALIZER(accept_filtlsthd);
59 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
61 static int unloadable = 0;
63 SYSCTL_NODE(_net, OID_AUTO, accf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
65 SYSCTL_INT(_net_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
66 "Allow unload of accept filters (not recommended)");
69 * Must be passed a malloc'd structure so we don't explode if the kld is
70 * unloaded, we leak the struct on deallocation to deal with this, but if a
71 * filter is loaded with the same name as a leaked one we re-use the entry.
74 accept_filt_add(struct accept_filter *filt)
76 struct accept_filter *p;
79 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
80 if (strcmp(p->accf_name, filt->accf_name) == 0) {
81 if (p->accf_callback != NULL) {
82 ACCEPT_FILTER_UNLOCK();
85 p->accf_callback = filt->accf_callback;
86 ACCEPT_FILTER_UNLOCK();
93 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
94 ACCEPT_FILTER_UNLOCK();
99 accept_filt_del(char *name)
101 struct accept_filter *p;
103 p = accept_filt_get(name);
107 p->accf_callback = NULL;
111 struct accept_filter *
112 accept_filt_get(char *name)
114 struct accept_filter *p;
116 ACCEPT_FILTER_LOCK();
117 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
118 if (strcmp(p->accf_name, name) == 0)
120 ACCEPT_FILTER_UNLOCK();
126 accept_filt_generic_mod_event(module_t mod, int event, void *data)
128 struct accept_filter *p;
129 struct accept_filter *accfp = (struct accept_filter *) data;
134 p = malloc(sizeof(*p), M_ACCF, M_WAITOK);
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 accept_filt_getopt(struct socket *so, struct sockopt *sopt)
167 struct accept_filter_arg *afap;
171 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK | M_ZERO);
173 if (!SOLISTENING(so)) {
177 if (so->sol_accept_filter == NULL) {
181 strcpy(afap->af_name, so->sol_accept_filter->accf_name);
182 if (so->sol_accept_filter_str != NULL)
183 strcpy(afap->af_arg, so->sol_accept_filter_str);
187 error = sooptcopyout(sopt, afap, sizeof(*afap));
193 accept_filt_setopt(struct socket *so, struct sockopt *sopt)
195 struct accept_filter_arg *afap;
196 struct accept_filter *afp;
197 char *accept_filter_str = NULL;
198 void *accept_filter_arg = NULL;
202 * Handle the simple delete case first.
204 if (sopt == NULL || sopt->sopt_val == NULL) {
205 struct socket *sp, *sp1;
209 if (!SOLISTENING(so)) {
213 if (so->sol_accept_filter == NULL) {
217 if (so->sol_accept_filter->accf_destroy != NULL)
218 so->sol_accept_filter->accf_destroy(so);
219 if (so->sol_accept_filter_str != NULL)
220 free(so->sol_accept_filter_str, M_ACCF);
221 so->sol_accept_filter = NULL;
222 so->sol_accept_filter_arg = NULL;
223 so->sol_accept_filter_str = NULL;
224 so->so_options &= ~SO_ACCEPTFILTER;
227 * Move from incomplete queue to complete only those
228 * connections, that are blocked by us.
231 TAILQ_FOREACH_SAFE(sp, &so->sol_incomp, so_list, sp1) {
233 if (sp->so_options & SO_ACCEPTFILTER) {
234 TAILQ_REMOVE(&so->sol_incomp, sp, so_list);
235 TAILQ_INSERT_TAIL(&so->sol_comp, sp, so_list);
236 sp->so_qstate = SQ_COMP;
237 sp->so_options &= ~SO_ACCEPTFILTER;
245 solisten_wakeup(so); /* unlocks */
252 * Pre-allocate any memory we may need later to avoid blocking at
253 * untimely moments. This does not optimize for invalid arguments.
255 afap = malloc(sizeof(*afap), M_TEMP, M_WAITOK);
256 error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
257 afap->af_name[sizeof(afap->af_name)-1] = '\0';
258 afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
263 afp = accept_filt_get(afap->af_name);
268 if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
269 size_t len = strlen(afap->af_name) + 1;
270 accept_filter_str = malloc(len, M_ACCF, M_WAITOK);
271 strcpy(accept_filter_str, afap->af_name);
275 * Require a listen socket; don't try to replace an existing filter
276 * without first removing it.
279 if (__predict_false(!SOLISTENING(so))) {
283 if (__predict_false(so->sol_accept_filter != NULL)) {
289 * Invoke the accf_create() method of the filter if required. The
290 * socket mutex is held over this call, so create methods for filters
293 if (afp->accf_create != NULL) {
294 accept_filter_arg = afp->accf_create(so, afap->af_arg);
295 if (accept_filter_arg == NULL) {
300 so->sol_accept_filter = afp;
301 so->sol_accept_filter_arg = accept_filter_arg;
302 so->sol_accept_filter_str = accept_filter_str;
303 accept_filter_str = NULL;
304 so->so_options |= SO_ACCEPTFILTER;
307 if (accept_filter_str != NULL)
308 free(accept_filter_str, M_ACCF);