1 /* $NetBSD: uipc_accf.c,v 1.13 2014/02/25 18:30:11 pooka 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 1.13 2014/02/25 18:30:11 pooka 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 static struct sysctllog *ctllog; 91 static void 92 sysctl_net_inet_accf_setup(void) 93 { 94 95 sysctl_createv(&ctllog, 0, NULL, NULL, 96 CTLFLAG_PERMANENT, 97 CTLTYPE_NODE, "inet", NULL, 98 NULL, 0, NULL, 0, 99 CTL_NET, PF_INET, CTL_EOL); 100 sysctl_createv(&ctllog, 0, NULL, NULL, 101 CTLFLAG_PERMANENT, 102 CTLTYPE_NODE, "accf", 103 SYSCTL_DESCR("Accept filters"), 104 NULL, 0, NULL, 0, 105 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL); 106 } 107 108 int 109 accept_filt_add(struct accept_filter *filt) 110 { 111 struct accept_filter *p; 112 113 accept_filter_init(); 114 115 rw_enter(&accept_filter_lock, RW_WRITER); 116 LIST_FOREACH(p, &accept_filtlsthd, accf_next) { 117 if (strcmp(p->accf_name, filt->accf_name) == 0) { 118 rw_exit(&accept_filter_lock); 119 return EEXIST; 120 } 121 } 122 LIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 123 rw_exit(&accept_filter_lock); 124 125 return 0; 126 } 127 128 int 129 accept_filt_del(struct accept_filter *p) 130 { 131 132 rw_enter(&accept_filter_lock, RW_WRITER); 133 if (p->accf_refcnt != 0) { 134 rw_exit(&accept_filter_lock); 135 return EBUSY; 136 } 137 LIST_REMOVE(p, accf_next); 138 rw_exit(&accept_filter_lock); 139 140 return 0; 141 } 142 143 struct accept_filter * 144 accept_filt_get(char *name) 145 { 146 struct accept_filter *p; 147 char buf[32]; 148 u_int gen; 149 150 do { 151 rw_enter(&accept_filter_lock, RW_READER); 152 LIST_FOREACH(p, &accept_filtlsthd, accf_next) { 153 if (strcmp(p->accf_name, name) == 0) { 154 atomic_inc_uint(&p->accf_refcnt); 155 break; 156 } 157 } 158 rw_exit(&accept_filter_lock); 159 if (p != NULL) { 160 break; 161 } 162 /* Try to autoload a module to satisfy the request. */ 163 strcpy(buf, "accf_"); 164 strlcat(buf, name, sizeof(buf)); 165 gen = module_gen; 166 (void)module_autoload(buf, MODULE_CLASS_ANY); 167 } while (gen != module_gen); 168 169 return p; 170 } 171 172 /* 173 * Accept filter initialization routine. 174 * This should be called only once. 175 */ 176 177 static int 178 accept_filter_init0(void) 179 { 180 181 rw_init(&accept_filter_lock); 182 sysctl_net_inet_accf_setup(); 183 184 return 0; 185 } 186 187 /* 188 * Initialization routine: This can also be replaced with 189 * accept_filt_generic_mod_event for attaching new accept filter. 190 */ 191 192 void 193 accept_filter_init(void) 194 { 195 static ONCE_DECL(accept_filter_init_once); 196 197 RUN_ONCE(&accept_filter_init_once, accept_filter_init0); 198 } 199 200 int 201 accept_filt_getopt(struct socket *so, struct sockopt *sopt) 202 { 203 struct accept_filter_arg afa; 204 int error; 205 206 KASSERT(solocked(so)); 207 208 if ((so->so_options & SO_ACCEPTCONN) == 0) { 209 error = EINVAL; 210 goto out; 211 } 212 if ((so->so_options & SO_ACCEPTFILTER) == 0) { 213 error = EINVAL; 214 goto out; 215 } 216 217 memset(&afa, 0, sizeof(afa)); 218 strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name); 219 if (so->so_accf->so_accept_filter_str != NULL) 220 strcpy(afa.af_arg, so->so_accf->so_accept_filter_str); 221 error = sockopt_set(sopt, &afa, sizeof(afa)); 222 out: 223 return error; 224 } 225 226 /* 227 * Simple delete case, with socket locked. 228 */ 229 int 230 accept_filt_clear(struct socket *so) 231 { 232 struct accept_filter_arg afa; 233 struct accept_filter *afp; 234 struct socket *so2, *next; 235 struct so_accf *af; 236 237 KASSERT(solocked(so)); 238 239 if ((so->so_options & SO_ACCEPTCONN) == 0) { 240 return EINVAL; 241 } 242 if (so->so_accf != NULL) { 243 /* Break in-flight processing. */ 244 for (so2 = TAILQ_FIRST(&so->so_q0); so2 != NULL; so2 = next) { 245 next = TAILQ_NEXT(so2, so_qe); 246 if (so2->so_upcall == NULL) { 247 continue; 248 } 249 so2->so_upcall = NULL; 250 so2->so_upcallarg = NULL; 251 so2->so_options &= ~SO_ACCEPTFILTER; 252 so2->so_rcv.sb_flags &= ~SB_UPCALL; 253 soisconnected(so2); 254 } 255 af = so->so_accf; 256 afp = af->so_accept_filter; 257 if (afp != NULL && afp->accf_destroy != NULL) { 258 (*afp->accf_destroy)(so); 259 } 260 if (af->so_accept_filter_str != NULL) { 261 kmem_free(af->so_accept_filter_str, 262 sizeof(afa.af_name)); 263 } 264 kmem_free(af, sizeof(*af)); 265 so->so_accf = NULL; 266 atomic_dec_uint(&afp->accf_refcnt); 267 } 268 so->so_options &= ~SO_ACCEPTFILTER; 269 return 0; 270 } 271 272 /* 273 * setsockopt() for accept filters. Called with the socket unlocked, 274 * will always return it locked. 275 */ 276 int 277 accept_filt_setopt(struct socket *so, const struct sockopt *sopt) 278 { 279 struct accept_filter_arg afa; 280 struct accept_filter *afp; 281 struct so_accf *newaf; 282 int error; 283 284 accept_filter_init(); 285 286 if (sopt == NULL || sopt->sopt_size == 0) { 287 solock(so); 288 return accept_filt_clear(so); 289 } 290 291 /* 292 * Pre-allocate any memory we may need later to avoid blocking at 293 * untimely moments. This does not optimize for invalid arguments. 294 */ 295 error = sockopt_get(sopt, &afa, sizeof(afa)); 296 if (error) { 297 solock(so); 298 return error; 299 } 300 afa.af_name[sizeof(afa.af_name)-1] = '\0'; 301 afa.af_arg[sizeof(afa.af_arg)-1] = '\0'; 302 afp = accept_filt_get(afa.af_name); 303 if (afp == NULL) { 304 solock(so); 305 return ENOENT; 306 } 307 /* 308 * Allocate the new accept filter instance storage. We may 309 * have to free it again later if we fail to attach it. If 310 * attached properly, 'newaf' is NULLed to avoid a free() 311 * while in use. 312 */ 313 newaf = kmem_zalloc(sizeof(*newaf), KM_SLEEP); 314 if (afp->accf_create != NULL && afa.af_name[0] != '\0') { 315 /* 316 * FreeBSD did a variable-size allocation here 317 * with the actual string length from afa.af_name 318 * but it is so short, why bother tracking it? 319 * XXX as others have noted, this is an API mistake; 320 * XXX accept_filter_arg should have a mandatory namelen. 321 * XXX (but it's a bit too late to fix that now) 322 */ 323 newaf->so_accept_filter_str = 324 kmem_alloc(sizeof(afa.af_name), KM_SLEEP); 325 strcpy(newaf->so_accept_filter_str, afa.af_name); 326 } 327 328 /* 329 * Require a listen socket; don't try to replace an existing filter 330 * without first removing it. 331 */ 332 solock(so); 333 if ((so->so_options & SO_ACCEPTCONN) == 0 || so->so_accf != NULL) { 334 error = EINVAL; 335 goto out; 336 } 337 338 /* 339 * Invoke the accf_create() method of the filter if required. The 340 * socket lock is held over this call, so create methods for filters 341 * shouldn't block. 342 */ 343 if (afp->accf_create != NULL) { 344 newaf->so_accept_filter_arg = 345 (*afp->accf_create)(so, afa.af_arg); 346 if (newaf->so_accept_filter_arg == NULL) { 347 error = EINVAL; 348 goto out; 349 } 350 } 351 newaf->so_accept_filter = afp; 352 so->so_accf = newaf; 353 so->so_options |= SO_ACCEPTFILTER; 354 newaf = NULL; 355 out: 356 if (newaf != NULL) { 357 if (newaf->so_accept_filter_str != NULL) 358 kmem_free(newaf->so_accept_filter_str, 359 sizeof(afa.af_name)); 360 kmem_free(newaf, sizeof(*newaf)); 361 atomic_dec_uint(&afp->accf_refcnt); 362 } 363 return error; 364 } 365