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 * $FreeBSD: src/sys/kern/uipc_accf.c,v 1.2.2.2 2000/09/20 21:19:21 ps Exp $ 28 */ 29 30 #define ACCEPT_FILTER_MOD 31 32 #include "opt_param.h" 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/domain.h> 36 #include <sys/kernel.h> 37 #include <sys/proc.h> 38 #include <sys/malloc.h> 39 #include <sys/mbuf.h> 40 #include <sys/protosw.h> 41 #include <sys/sysctl.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 #include <sys/queue.h> 45 46 static SLIST_HEAD(, accept_filter) accept_filtlsthd = 47 SLIST_HEAD_INITIALIZER(&accept_filtlsthd); 48 49 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data"); 50 51 static int unloadable = 0; 52 53 SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */ 54 SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters"); 55 SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0, 56 "Allow unload of accept filters (not recommended)"); 57 58 /* 59 * must be passed a malloc'd structure so we don't explode if the kld 60 * is unloaded, we leak the struct on deallocation to deal with this, 61 * but if a filter is loaded with the same name as a leaked one we re-use 62 * the entry. 63 */ 64 int 65 accept_filt_add(struct accept_filter *filt) 66 { 67 struct accept_filter *p; 68 69 SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 70 if (strcmp(p->accf_name, filt->accf_name) == 0) { 71 if (p->accf_callback != NULL) { 72 return (EEXIST); 73 } else { 74 p->accf_callback = filt->accf_callback; 75 FREE(filt, M_ACCF); 76 return (0); 77 } 78 } 79 80 if (p == NULL) 81 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 82 return (0); 83 } 84 85 int 86 accept_filt_del(char *name) 87 { 88 struct accept_filter *p; 89 90 p = accept_filt_get(name); 91 if (p == NULL) 92 return (ENOENT); 93 94 p->accf_callback = NULL; 95 return (0); 96 } 97 98 struct accept_filter * 99 accept_filt_get(char *name) 100 { 101 struct accept_filter *p; 102 103 SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 104 if (strcmp(p->accf_name, name) == 0) 105 return (p); 106 107 return (NULL); 108 } 109 110 int 111 accept_filt_generic_mod_event(module_t mod, int event, void *data) 112 { 113 struct accept_filter *p; 114 struct accept_filter *accfp = (struct accept_filter *) data; 115 int s, error; 116 117 switch (event) { 118 case MOD_LOAD: 119 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK); 120 bcopy(accfp, p, sizeof(*p)); 121 s = splnet(); 122 error = accept_filt_add(p); 123 splx(s); 124 break; 125 126 case MOD_UNLOAD: 127 /* 128 * Do not support unloading yet. we don't keep track of refcounts 129 * and unloading an accept filter callback and then having it called 130 * is a bad thing. A simple fix would be to track the refcount 131 * in the struct accept_filter. 132 */ 133 if (unloadable != 0) { 134 s = splnet(); 135 error = accept_filt_del(accfp->accf_name); 136 splx(s); 137 } else 138 error = EOPNOTSUPP; 139 break; 140 141 case MOD_SHUTDOWN: 142 error = 0; 143 break; 144 145 default: 146 error = EOPNOTSUPP; 147 break; 148 } 149 150 return (error); 151 } 152