1 /* $NetBSD: uipc_accf.c,v 1.8 2008/11/20 10:00:54 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software developed for The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 2000 Paycounter, Inc. 34 * Copyright (c) 2005 Robert N. M. Watson 35 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org> 36 * All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 48 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 49 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 50 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 51 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 52 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 53 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 54 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 55 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 56 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 57 * SUCH DAMAGE. 58 */ 59 60 #include <sys/cdefs.h> 61 __KERNEL_RCSID(0, "$NetBSD: uipc_accf.c,v 1.8 2008/11/20 10:00:54 ad Exp $"); 62 63 #define ACCEPT_FILTER_MOD 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/domain.h> 68 #include <sys/kernel.h> 69 #include <sys/lock.h> 70 #include <sys/kmem.h> 71 #include <sys/mbuf.h> 72 #include <sys/rwlock.h> 73 #include <sys/protosw.h> 74 #include <sys/sysctl.h> 75 #include <sys/socket.h> 76 #include <sys/socketvar.h> 77 #include <sys/queue.h> 78 #include <sys/once.h> 79 #include <sys/atomic.h> 80 #include <sys/module.h> 81 82 static krwlock_t accept_filter_lock; 83 84 static LIST_HEAD(, accept_filter) accept_filtlsthd = 85 LIST_HEAD_INITIALIZER(&accept_filtlsthd); 86 87 /* 88 * Names of Accept filter sysctl objects 89 */ 90 SYSCTL_SETUP(sysctl_net_inet_accf_setup, "sysctl net.inet.accf subtree setup") 91 { 92 93 sysctl_createv(clog, 0, NULL, NULL, 94 CTLFLAG_PERMANENT, 95 CTLTYPE_NODE, "net", NULL, 96 NULL, 0, NULL, 0, 97 CTL_NET, CTL_EOL); 98 sysctl_createv(clog, 0, NULL, NULL, 99 CTLFLAG_PERMANENT, 100 CTLTYPE_NODE, "inet", NULL, 101 NULL, 0, NULL, 0, 102 CTL_NET, PF_INET, CTL_EOL); 103 sysctl_createv(clog, 0, NULL, NULL, 104 CTLFLAG_PERMANENT, 105 CTLTYPE_NODE, "accf", 106 SYSCTL_DESCR("Accept filters"), 107 NULL, 0, NULL, 0, 108 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL); 109 } 110 111 int 112 accept_filt_add(struct accept_filter *filt) 113 { 114 struct accept_filter *p; 115 116 accept_filter_init(); 117 118 rw_enter(&accept_filter_lock, RW_WRITER); 119 LIST_FOREACH(p, &accept_filtlsthd, accf_next) { 120 if (strcmp(p->accf_name, filt->accf_name) == 0) { 121 rw_exit(&accept_filter_lock); 122 return EEXIST; 123 } 124 } 125 LIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 126 rw_exit(&accept_filter_lock); 127 128 return 0; 129 } 130 131 int 132 accept_filt_del(struct accept_filter *p) 133 { 134 135 rw_enter(&accept_filter_lock, RW_WRITER); 136 if (p->accf_refcnt != 0) { 137 rw_exit(&accept_filter_lock); 138 return EBUSY; 139 } 140 LIST_REMOVE(p, accf_next); 141 rw_exit(&accept_filter_lock); 142 143 return 0; 144 } 145 146 struct accept_filter * 147 accept_filt_get(char *name) 148 { 149 struct accept_filter *p; 150 char buf[32]; 151 u_int gen; 152 153 do { 154 rw_enter(&accept_filter_lock, RW_READER); 155 LIST_FOREACH(p, &accept_filtlsthd, accf_next) { 156 if (strcmp(p->accf_name, name) == 0) { 157 atomic_inc_uint(&p->accf_refcnt); 158 break; 159 } 160 } 161 rw_exit(&accept_filter_lock); 162 if (p != NULL) { 163 break; 164 } 165 /* Try to autoload a module to satisfy the request. */ 166 strcpy(buf, "accf_"); 167 strlcat(buf, name, sizeof(buf)); 168 mutex_enter(&module_lock); 169 gen = module_gen; 170 (void)module_autoload(buf, MODULE_CLASS_ANY); 171 mutex_exit(&module_lock); 172 } while (gen != module_gen); 173 174 return p; 175 } 176 177 /* 178 * Accept filter initialization routine. 179 * This should be called only once. 180 */ 181 182 static int 183 accept_filter_init0(void) 184 { 185 186 rw_init(&accept_filter_lock); 187 188 return 0; 189 } 190 191 /* 192 * Initialization routine: This can also be replaced with 193 * accept_filt_generic_mod_event for attaching new accept filter. 194 */ 195 196 void 197 accept_filter_init(void) 198 { 199 static ONCE_DECL(accept_filter_init_once); 200 201 RUN_ONCE(&accept_filter_init_once, accept_filter_init0); 202 } 203 204 int 205 accept_filt_getopt(struct socket *so, struct sockopt *sopt) 206 { 207 struct accept_filter_arg afa; 208 int error; 209 210 KASSERT(solocked(so)); 211 212 if ((so->so_options & SO_ACCEPTCONN) == 0) { 213 error = EINVAL; 214 goto out; 215 } 216 if ((so->so_options & SO_ACCEPTFILTER) == 0) { 217 error = EINVAL; 218 goto out; 219 } 220 221 memset(&afa, 0, sizeof(afa)); 222 strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name); 223 if (so->so_accf->so_accept_filter_str != NULL) 224 strcpy(afa.af_arg, so->so_accf->so_accept_filter_str); 225 error = sockopt_set(sopt, &afa, sizeof(afa)); 226 out: 227 return error; 228 } 229 230 /* 231 * Simple delete case, with socket locked. 232 */ 233 int 234 accept_filt_clear(struct socket *so) 235 { 236 struct accept_filter_arg afa; 237 struct accept_filter *afp; 238 struct socket *so2, *next; 239 struct so_accf *af; 240 241 KASSERT(solocked(so)); 242 243 if ((so->so_options & SO_ACCEPTCONN) == 0) { 244 return EINVAL; 245 } 246 if (so->so_accf != NULL) { 247 /* Break in-flight processing. */ 248 for (so2 = TAILQ_FIRST(&so->so_q0); so2 != NULL; so2 = next) { 249 next = TAILQ_NEXT(so2, so_qe); 250 if (so2->so_upcall == NULL) { 251 continue; 252 } 253 so2->so_upcall = NULL; 254 so2->so_upcallarg = NULL; 255 so2->so_options &= ~SO_ACCEPTFILTER; 256 so2->so_rcv.sb_flags &= ~SB_UPCALL; 257 soisconnected(so2); 258 } 259 af = so->so_accf; 260 afp = af->so_accept_filter; 261 if (afp != NULL && afp->accf_destroy != NULL) { 262 (*afp->accf_destroy)(so); 263 } 264 if (af->so_accept_filter_str != NULL) { 265 kmem_free(af->so_accept_filter_str, 266 sizeof(afa.af_name)); 267 } 268 kmem_free(af, sizeof(*af)); 269 so->so_accf = NULL; 270 atomic_dec_uint(&afp->accf_refcnt); 271 } 272 so->so_options &= ~SO_ACCEPTFILTER; 273 return 0; 274 } 275 276 /* 277 * setsockopt() for accept filters. Called with the socket unlocked, 278 * will always return it locked. 279 */ 280 int 281 accept_filt_setopt(struct socket *so, const struct sockopt *sopt) 282 { 283 struct accept_filter_arg afa; 284 struct accept_filter *afp; 285 struct so_accf *newaf; 286 int error; 287 288 if (sopt == NULL || sopt->sopt_size == 0) { 289 solock(so); 290 return accept_filt_clear(so); 291 } 292 293 /* 294 * Pre-allocate any memory we may need later to avoid blocking at 295 * untimely moments. This does not optimize for invalid arguments. 296 */ 297 error = sockopt_get(sopt, &afa, sizeof(afa)); 298 if (error) { 299 solock(so); 300 return error; 301 } 302 afa.af_name[sizeof(afa.af_name)-1] = '\0'; 303 afa.af_arg[sizeof(afa.af_arg)-1] = '\0'; 304 afp = accept_filt_get(afa.af_name); 305 if (afp == NULL) { 306 solock(so); 307 return ENOENT; 308 } 309 /* 310 * Allocate the new accept filter instance storage. We may 311 * have to free it again later if we fail to attach it. If 312 * attached properly, 'newaf' is NULLed to avoid a free() 313 * while in use. 314 */ 315 newaf = kmem_zalloc(sizeof(*newaf), KM_SLEEP); 316 if (afp->accf_create != NULL && afa.af_name[0] != '\0') { 317 /* 318 * FreeBSD did a variable-size allocation here 319 * with the actual string length from afa.af_name 320 * but it is so short, why bother tracking it? 321 * XXX as others have noted, this is an API mistake; 322 * XXX accept_filter_arg should have a mandatory namelen. 323 * XXX (but it's a bit too late to fix that now) 324 */ 325 newaf->so_accept_filter_str = 326 kmem_alloc(sizeof(afa.af_name), KM_SLEEP); 327 strcpy(newaf->so_accept_filter_str, afa.af_name); 328 } 329 330 /* 331 * Require a listen socket; don't try to replace an existing filter 332 * without first removing it. 333 */ 334 solock(so); 335 if ((so->so_options & SO_ACCEPTCONN) == 0 || so->so_accf != NULL) { 336 error = EINVAL; 337 goto out; 338 } 339 340 /* 341 * Invoke the accf_create() method of the filter if required. The 342 * socket lock is held over this call, so create methods for filters 343 * shouldn't block. 344 */ 345 if (afp->accf_create != NULL) { 346 newaf->so_accept_filter_arg = 347 (*afp->accf_create)(so, afa.af_arg); 348 if (newaf->so_accept_filter_arg == NULL) { 349 error = EINVAL; 350 goto out; 351 } 352 } 353 newaf->so_accept_filter = afp; 354 so->so_accf = newaf; 355 so->so_options |= SO_ACCEPTFILTER; 356 newaf = NULL; 357 out: 358 if (newaf != NULL) { 359 if (newaf->so_accept_filter_str != NULL) 360 kmem_free(newaf->so_accept_filter_str, 361 sizeof(afa.af_name)); 362 kmem_free(newaf, sizeof(*newaf)); 363 atomic_dec_uint(&afp->accf_refcnt); 364 } 365 return error; 366 } 367