2 * Copyright (c) 2000 Paycounter, Inc.
3 * Copyright (c) 2005 Robert N. M. Watson
4 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
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, 0, "Accept filters");
64 SYSCTL_INT(_net_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 p = malloc(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_getopt_accept_filter(struct socket *so, struct sockopt *sopt)
167 struct accept_filter_arg *afap;
171 afap = malloc(sizeof(*afap), M_TEMP,
174 if ((so->so_options & SO_ACCEPTCONN) == 0) {
178 if ((so->so_options & SO_ACCEPTFILTER) == 0) {
182 strcpy(afap->af_name, so->so_accf->so_accept_filter->accf_name);
183 if (so->so_accf->so_accept_filter_str != NULL)
184 strcpy(afap->af_arg, so->so_accf->so_accept_filter_str);
188 error = sooptcopyout(sopt, afap, sizeof(*afap));
194 do_setopt_accept_filter(struct socket *so, struct sockopt *sopt)
196 struct accept_filter_arg *afap;
197 struct accept_filter *afp;
198 struct so_accf *newaf;
202 * Handle the simple delete case first.
204 if (sopt == NULL || sopt->sopt_val == NULL) {
206 if ((so->so_options & SO_ACCEPTCONN) == 0) {
210 if (so->so_accf != NULL) {
211 struct so_accf *af = so->so_accf;
212 if (af->so_accept_filter != NULL &&
213 af->so_accept_filter->accf_destroy != NULL) {
214 af->so_accept_filter->accf_destroy(so);
216 if (af->so_accept_filter_str != NULL)
217 free(af->so_accept_filter_str, M_ACCF);
221 so->so_options &= ~SO_ACCEPTFILTER;
227 * Pre-allocate any memory we may need later to avoid blocking at
228 * untimely moments. This does not optimize for invalid arguments.
230 afap = malloc(sizeof(*afap), M_TEMP,
232 error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap);
233 afap->af_name[sizeof(afap->af_name)-1] = '\0';
234 afap->af_arg[sizeof(afap->af_arg)-1] = '\0';
239 afp = accept_filt_get(afap->af_name);
245 * Allocate the new accept filter instance storage. We may
246 * have to free it again later if we fail to attach it. If
247 * attached properly, 'newaf' is NULLed to avoid a free()
250 newaf = malloc(sizeof(*newaf), M_ACCF, M_WAITOK |
252 if (afp->accf_create != NULL && afap->af_name[0] != '\0') {
253 int len = strlen(afap->af_name) + 1;
254 newaf->so_accept_filter_str = malloc(len, M_ACCF,
256 strcpy(newaf->so_accept_filter_str, afap->af_name);
260 * Require a listen socket; don't try to replace an existing filter
261 * without first removing it.
264 if (((so->so_options & SO_ACCEPTCONN) == 0) ||
265 (so->so_accf != NULL)) {
271 * Invoke the accf_create() method of the filter if required. The
272 * socket mutex is held over this call, so create methods for filters
275 if (afp->accf_create != NULL) {
276 newaf->so_accept_filter_arg =
277 afp->accf_create(so, afap->af_arg);
278 if (newaf->so_accept_filter_arg == NULL) {
283 newaf->so_accept_filter = afp;
285 so->so_options |= SO_ACCEPTFILTER;
290 if (newaf->so_accept_filter_str != NULL)
291 free(newaf->so_accept_filter_str, M_ACCF);