| 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 | |