1 /* 2 * Copyright (c) 2000 Paycounter, Inc. 3 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 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. 14 * 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 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #define ACCEPT_FILTER_MOD 32 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> 38 #include <sys/lock.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.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> 48 49 static struct mtx accept_filter_mtx; 50 MTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx", 51 MTX_DEF); 52 #define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx) 53 #define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx) 54 55 static SLIST_HEAD(, accept_filter) accept_filtlsthd = 56 SLIST_HEAD_INITIALIZER(&accept_filtlsthd); 57 58 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data"); 59 60 static int unloadable = 0; 61 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)"); 66 67 /* 68 * must be passed a malloc'd structure so we don't explode if the kld 69 * is unloaded, we leak the struct on deallocation to deal with this, 70 * but if a filter is loaded with the same name as a leaked one we re-use 71 * the entry. 72 */ 73 int 74 accept_filt_add(struct accept_filter *filt) 75 { 76 struct accept_filter *p; 77 78 ACCEPT_FILTER_LOCK(); 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(); 83 return (EEXIST); 84 } else { 85 p->accf_callback = filt->accf_callback; 86 ACCEPT_FILTER_UNLOCK(); 87 FREE(filt, M_ACCF); 88 return (0); 89 } 90 } 91 92 if (p == NULL) 93 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 94 ACCEPT_FILTER_UNLOCK(); 95 return (0); 96 } 97 98 int 99 accept_filt_del(char *name) 100 { 101 struct accept_filter *p; 102 103 p = accept_filt_get(name); 104 if (p == NULL) 105 return (ENOENT); 106 107 p->accf_callback = NULL; 108 return (0); 109 } 110 111 struct accept_filter * 112 accept_filt_get(char *name) 113 { 114 struct accept_filter *p; 115 116 ACCEPT_FILTER_LOCK(); 117 SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 118 if (strcmp(p->accf_name, name) == 0) 119 break; 120 ACCEPT_FILTER_UNLOCK(); 121 122 return (p); 123 } 124 125 int 126 accept_filt_generic_mod_event(module_t mod, int event, void *data) 127 { 128 struct accept_filter *p; 129 struct accept_filter *accfp = (struct accept_filter *) data; 130 int error; 131 132 switch (event) { 133 case MOD_LOAD: 134 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK); 135 bcopy(accfp, p, sizeof(*p)); 136 error = accept_filt_add(p); 137 break; 138 139 case MOD_UNLOAD: 140 /* 141 * Do not support unloading yet. we don't keep track of refcounts 142 * and unloading an accept filter callback and then having it called 143 * is a bad thing. A simple fix would be to track the refcount 144 * in the struct accept_filter. 145 */ 146 if (unloadable != 0) { 147 error = accept_filt_del(accfp->accf_name); 148 } else 149 error = EOPNOTSUPP; 150 break; 151 152 case MOD_SHUTDOWN: 153 error = 0; 154 break; 155 156 default: 157 error = EOPNOTSUPP; 158 break; 159 } 160 161 return (error); 162 } 163