1 /* $NetBSD: uipc_accf.c,v 1.16 2024/12/06 18:44:00 riastradh 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 (at) paycounter.com>, <alfred (at) 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 1.16 2024/12/06 18:44:00 riastradh Exp $"); 62 63 #define ACCEPT_FILTER_MOD 64 65 #include <sys/param.h> 66 #include <sys/types.h> 67 68 #include <sys/atomic.h> 69 #include <sys/domain.h> 70 #include <sys/kernel.h> 71 #include <sys/kmem.h> 72 #include <sys/lock.h> 73 #include <sys/mbuf.h> 74 #include <sys/module.h> 75 #include <sys/once.h> 76 #include <sys/protosw.h> 77 #include <sys/queue.h> 78 #include <sys/rwlock.h> 79 #include <sys/sdt.h> 80 #include <sys/socket.h> 81 #include <sys/socketvar.h> 82 #include <sys/sysctl.h> 83 #include <sys/systm.h> 84 85 static krwlock_t accept_filter_lock; 86 87 static LIST_HEAD(, accept_filter) accept_filtlsthd = 88 LIST_HEAD_INITIALIZER(&accept_filtlsthd); 89 90 /* 91 * Names of Accept filter sysctl objects 92 */ 93 static struct sysctllog *ctllog; 94 static void 95 sysctl_net_inet_accf_setup(void) 96 { 97 98 sysctl_createv(&ctllog, 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(&ctllog, 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 SET_ERROR(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 SET_ERROR(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 gen = module_gen; 169 (void)module_autoload(buf, MODULE_CLASS_ANY); 170 } while (gen != module_gen); 171 172 return p; 173 } 174 175 /* 176 * Accept filter initialization routine. 177 * This should be called only once. 178 */ 179 180 static int 181 accept_filter_init0(void) 182 { 183 184 rw_init(&accept_filter_lock); 185 sysctl_net_inet_accf_setup(); 186 187 return 0; 188 } 189 190 /* 191 * Initialization routine: This can also be replaced with 192 * accept_filt_generic_mod_event for attaching new accept filter. 193 */ 194 195 void 196 accept_filter_init(void) 197 { 198 static ONCE_DECL(accept_filter_init_once); 199 200 RUN_ONCE(&accept_filter_init_once, accept_filter_init0); 201 } 202 203 int 204 accept_filt_getopt(struct socket *so, struct sockopt *sopt) 205 { 206 struct accept_filter_arg afa; 207 int error; 208 209 KASSERT(solocked(so)); 210 211 if ((so->so_options & SO_ACCEPTCONN) == 0) { 212 error = SET_ERROR(EINVAL); 213 goto out; 214 } 215 if ((so->so_options & SO_ACCEPTFILTER) == 0) { 216 error = SET_ERROR(EINVAL); 217 goto out; 218 } 219 220 memset(&afa, 0, sizeof(afa)); 221 strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name); 222 if (so->so_accf->so_accept_filter_str != NULL) 223 strcpy(afa.af_arg, so->so_accf->so_accept_filter_str); 224 error = sockopt_set(sopt, &afa, sizeof(afa)); 225 out: 226 return error; 227 } 228 229 /* 230 * Simple delete case, with socket locked. 231 */ 232 int 233 accept_filt_clear(struct socket *so) 234 { 235 struct accept_filter_arg afa; 236 struct accept_filter *afp; 237 struct socket *so2, *next; 238 struct so_accf *af; 239 240 KASSERT(solocked(so)); 241 242 if ((so->so_options & SO_ACCEPTCONN) == 0) { 243 return SET_ERROR(EINVAL); 244 } 245 if (so->so_accf != NULL) { 246 /* Break in-flight processing. */ 247 for (so2 = TAILQ_FIRST(&so->so_q0); so2 != NULL; so2 = next) { 248 next = TAILQ_NEXT(so2, so_qe); 249 if (so2->so_upcall == NULL) { 250 continue; 251 } 252 so2->so_upcall = NULL; 253 so2->so_upcallarg = NULL; 254 so2->so_options &= ~SO_ACCEPTFILTER; 255 so2->so_rcv.sb_flags &= ~SB_UPCALL; 256 soisconnected(so2); 257 } 258 af = so->so_accf; 259 afp = af->so_accept_filter; 260 if (afp != NULL && afp->accf_destroy != NULL) { 261 (*afp->accf_destroy)(so); 262 } 263 if (af->so_accept_filter_str != NULL) { 264 kmem_free(af->so_accept_filter_str, 265 sizeof(afa.af_name)); 266 } 267 kmem_free(af, sizeof(*af)); 268 so->so_accf = NULL; 269 atomic_dec_uint(&afp->accf_refcnt); 270 } 271 so->so_options &= ~SO_ACCEPTFILTER; 272 return 0; 273 } 274 275 /* 276 * setsockopt() for accept filters. Called with the socket unlocked, 277 * will always return it locked. 278 */ 279 int 280 accept_filt_setopt(struct socket *so, const struct sockopt *sopt) 281 { 282 struct accept_filter_arg afa; 283 struct accept_filter *afp; 284 struct so_accf *newaf; 285 int error; 286 287 accept_filter_init(); 288 289 if (sopt == NULL || sopt->sopt_size == 0) { 290 solock(so); 291 return accept_filt_clear(so); 292 } 293 294 /* 295 * Pre-allocate any memory we may need later to avoid blocking at 296 * untimely moments. This does not optimize for invalid arguments. 297 */ 298 error = sockopt_get(sopt, &afa, sizeof(afa)); 299 if (error) { 300 solock(so); 301 return error; 302 } 303 afa.af_name[sizeof(afa.af_name)-1] = '\0'; 304 afa.af_arg[sizeof(afa.af_arg)-1] = '\0'; 305 afp = accept_filt_get(afa.af_name); 306 if (afp == NULL) { 307 solock(so); 308 return SET_ERROR(ENOENT); 309 } 310 /* 311 * Allocate the new accept filter instance storage. We may 312 * have to free it again later if we fail to attach it. If 313 * attached properly, 'newaf' is NULLed to avoid a free() 314 * while in use. 315 */ 316 newaf = kmem_zalloc(sizeof(*newaf), KM_SLEEP); 317 if (afp->accf_create != NULL && afa.af_name[0] != '\0') { 318 /* 319 * FreeBSD did a variable-size allocation here 320 * with the actual string length from afa.af_name 321 * but it is so short, why bother tracking it? 322 * XXX as others have noted, this is an API mistake; 323 * XXX accept_filter_arg should have a mandatory namelen. 324 * XXX (but it's a bit too late to fix that now) 325 */ 326 newaf->so_accept_filter_str = 327 kmem_alloc(sizeof(afa.af_name), KM_SLEEP); 328 strcpy(newaf->so_accept_filter_str, afa.af_name); 329 } 330 331 /* 332 * Require a listen socket; don't try to replace an existing filter 333 * without first removing it. 334 */ 335 solock(so); 336 if ((so->so_options & SO_ACCEPTCONN) == 0 || so->so_accf != NULL) { 337 error = SET_ERROR(EINVAL); 338 goto out; 339 } 340 341 /* 342 * Invoke the accf_create() method of the filter if required. The 343 * socket lock is held over this call, so create methods for filters 344 * shouldn't block. 345 */ 346 if (afp->accf_create != NULL) { 347 newaf->so_accept_filter_arg = 348 (*afp->accf_create)(so, afa.af_arg); 349 if (newaf->so_accept_filter_arg == NULL) { 350 error = SET_ERROR(EINVAL); 351 goto out; 352 } 353 } 354 newaf->so_accept_filter = afp; 355 so->so_accf = newaf; 356 so->so_options |= SO_ACCEPTFILTER; 357 newaf = NULL; 358 out: 359 if (newaf != NULL) { 360 if (newaf->so_accept_filter_str != NULL) 361 kmem_free(newaf->so_accept_filter_str, 362 sizeof(afa.af_name)); 363 kmem_free(newaf, sizeof(*newaf)); 364 atomic_dec_uint(&afp->accf_refcnt); 365 } 366 return error; 367 } 368
Indexes created Sat Sep 20 22:09:52 GMT 2025