uipc_accf.c revision 1.3.2.3
1 /* $NetBSD: uipc_accf.c,v 1.3.2.3 2008/10/05 20:11:32 mjf Exp $ */ 2 3 /*- 4 * Copyright (c) 2000 Paycounter, Inc. 5 * Copyright (c) 2005 Robert N. M. Watson 6 * Author: Alfred Perlstein <alfred (at) paycounter.com>, <alfred (at) FreeBSD.org> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __KERNEL_RCSID(0, "$NetBSD: uipc_accf.c,v 1.3.2.3 2008/10/05 20:11:32 mjf Exp $"); 33 34 #define ACCEPT_FILTER_MOD 35 36 #include "opt_inet.h" 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/domain.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #include <sys/mbuf.h> 44 #include <sys/lkm.h> 45 #include <sys/mutex.h> 46 #include <sys/protosw.h> 47 #include <sys/sysctl.h> 48 #include <sys/socket.h> 49 #include <sys/socketvar.h> 50 #include <sys/queue.h> 51 #include <sys/once.h> 52 53 static kmutex_t accept_filter_mtx; 54 #define ACCEPT_FILTER_LOCK() mutex_spin_enter(&accept_filter_mtx) 55 #define ACCEPT_FILTER_UNLOCK() mutex_spin_exit(&accept_filter_mtx); 56 #define SOCK_LOCK(so) 57 #define SOCK_UNLOCK(so) 58 59 static SLIST_HEAD(, accept_filter) accept_filtlsthd = 60 SLIST_HEAD_INITIALIZER(&accept_filtlsthd); 61 62 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data"); 63 64 static int unloadable = 0; 65 66 /* 67 * Names of Accept filter sysctl objects 68 */ 69 70 #define ACCFCTL_UNLOADABLE 1 /* Allow module to be unloaded */ 71 72 73 SYSCTL_SETUP(sysctl_net_inet_accf_setup, "sysctl net.inet.accf subtree setup") 74 { 75 sysctl_createv(clog, 0, NULL, NULL, 76 CTLFLAG_PERMANENT, 77 CTLTYPE_NODE, "net", NULL, 78 NULL, 0, NULL, 0, 79 CTL_NET, CTL_EOL); 80 sysctl_createv(clog, 0, NULL, NULL, 81 CTLFLAG_PERMANENT, 82 CTLTYPE_NODE, "inet", NULL, 83 NULL, 0, NULL, 0, 84 CTL_NET, PF_INET, CTL_EOL); 85 sysctl_createv(clog, 0, NULL, NULL, 86 CTLFLAG_PERMANENT, 87 CTLTYPE_NODE, "accf", 88 SYSCTL_DESCR("Accept filters"), 89 NULL, 0, NULL, 0, 90 CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL); 91 sysctl_createv(clog, 0, NULL, NULL, 92 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 93 CTLTYPE_INT, "unloadable", 94 SYSCTL_DESCR("Allow unload of accept filters " 95 "(not recommended)"), 96 NULL, 0, &unloadable, 0, 97 CTL_NET, PF_INET, SO_ACCEPTFILTER, 98 ACCFCTL_UNLOADABLE, CTL_EOL); 99 } 100 101 /* 102 * Must be passed a malloc'd structure so we don't explode if the kld is 103 * unloaded, we leak the struct on deallocation to deal with this, but if a 104 * filter is loaded with the same name as a leaked one we re-use the entry. 105 */ 106 int 107 accept_filt_add(struct accept_filter *filt) 108 { 109 struct accept_filter *p; 110 111 ACCEPT_FILTER_LOCK(); 112 SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 113 if (strcmp(p->accf_name, filt->accf_name) == 0) { 114 if (p->accf_callback != NULL) { 115 ACCEPT_FILTER_UNLOCK(); 116 return (EEXIST); 117 } else { 118 p->accf_callback = filt->accf_callback; 119 ACCEPT_FILTER_UNLOCK(); 120 FREE(filt, M_ACCF); 121 return (0); 122 } 123 } 124 125 if (p == NULL) 126 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 127 ACCEPT_FILTER_UNLOCK(); 128 return (0); 129 } 130 131 int 132 accept_filt_del(char *name) 133 { 134 struct accept_filter *p; 135 136 p = accept_filt_get(name); 137 if (p == NULL) 138 return (ENOENT); 139 140 p->accf_callback = NULL; 141 return (0); 142 } 143 144 struct accept_filter * 145 accept_filt_get(char *name) 146 { 147 struct accept_filter *p; 148 149 ACCEPT_FILTER_LOCK(); 150 SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 151 if (strcmp(p->accf_name, name) == 0) 152 break; 153 ACCEPT_FILTER_UNLOCK(); 154 155 return (p); 156 } 157 158 /* 159 * Accept filter initialization routine. 160 * This should be called only once. 161 */ 162 163 static int 164 accept_filter_init0(void) 165 { 166 mutex_init(&accept_filter_mtx, MUTEX_DEFAULT, IPL_NET); 167 168 return 0; 169 } 170 171 /* 172 * Initialization routine: This can also be replaced with 173 * accept_filt_generic_mod_event for attaching new accept filter. 174 */ 175 176 void 177 accept_filter_init(void) 178 { 179 static ONCE_DECL(accept_filter_init_once); 180 181 RUN_ONCE(&accept_filter_init_once, accept_filter_init0); 182 } 183 184 int 185 accept_filt_generic_mod_event(struct lkm_table *lkmtp, int event, void *data) 186 { 187 struct accept_filter *p; 188 struct accept_filter *accfp = (struct accept_filter *) data; 189 int error; 190 191 switch (event) { 192 case LKM_E_LOAD: 193 accept_filter_init(); 194 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, 195 M_WAITOK); 196 bcopy(accfp, p, sizeof(*p)); 197 error = accept_filt_add(p); 198 break; 199 200 case LKM_E_UNLOAD: 201 /* 202 * Do not support unloading yet. we don't keep track of 203 * refcounts and unloading an accept filter callback and then 204 * having it called is a bad thing. A simple fix would be to 205 * track the refcount in the struct accept_filter. 206 */ 207 if (unloadable != 0) { 208 error = accept_filt_del(accfp->accf_name); 209 } else 210 error = EOPNOTSUPP; 211 break; 212 213 case LKM_E_STAT: 214 error = 0; 215 break; 216 217 default: 218 error = EOPNOTSUPP; 219 break; 220 } 221 222 return (error); 223 } 224 225 int 226 do_getopt_accept_filter(struct socket *so, struct sockopt *sopt) 227 { 228 struct accept_filter_arg afa; 229 int error; 230 231 SOCK_LOCK(so); 232 if ((so->so_options & SO_ACCEPTCONN) == 0) { 233 error = EINVAL; 234 goto out; 235 } 236 if ((so->so_options & SO_ACCEPTFILTER) == 0) { 237 error = EINVAL; 238 goto out; 239 } 240 241 memset(&afa, 0, sizeof(afa)); 242 strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name); 243 if (so->so_accf->so_accept_filter_str != NULL) 244 strcpy(afa.af_arg, so->so_accf->so_accept_filter_str); 245 error = sockopt_set(sopt, &afa, sizeof(afa)); 246 out: 247 SOCK_UNLOCK(so); 248 return (error); 249 } 250 251 int 252 do_setopt_accept_filter(struct socket *so, const struct sockopt *sopt) 253 { 254 struct accept_filter_arg afa; 255 struct accept_filter *afp; 256 struct so_accf *newaf; 257 int error; 258 259 /* 260 * Handle the simple delete case first. 261 */ 262 if (sopt == NULL || sopt->sopt_size == 0) { 263 SOCK_LOCK(so); 264 if ((so->so_options & SO_ACCEPTCONN) == 0) { 265 SOCK_UNLOCK(so); 266 return (EINVAL); 267 } 268 if (so->so_accf != NULL) { 269 struct so_accf *af = so->so_accf; 270 if (af->so_accept_filter != NULL && 271 af->so_accept_filter->accf_destroy != NULL) { 272 af->so_accept_filter->accf_destroy(so); 273 } 274 if (af->so_accept_filter_str != NULL) 275 FREE(af->so_accept_filter_str, M_ACCF); 276 FREE(af, M_ACCF); 277 so->so_accf = NULL; 278 } 279 so->so_options &= ~SO_ACCEPTFILTER; 280 SOCK_UNLOCK(so); 281 return (0); 282 } 283 284 /* 285 * Pre-allocate any memory we may need later to avoid blocking at 286 * untimely moments. This does not optimize for invalid arguments. 287 */ 288 error = sockopt_get(sopt, &afa, sizeof(afa)); 289 if (error) { 290 return (error); 291 } 292 afa.af_name[sizeof(afa.af_name)-1] = '\0'; 293 afa.af_arg[sizeof(afa.af_arg)-1] = '\0'; 294 afp = accept_filt_get(afa.af_name); 295 if (afp == NULL) { 296 return (ENOENT); 297 } 298 /* 299 * Allocate the new accept filter instance storage. We may 300 * have to free it again later if we fail to attach it. If 301 * attached properly, 'newaf' is NULLed to avoid a free() 302 * while in use. 303 */ 304 MALLOC(newaf, struct so_accf *, sizeof(*newaf), M_ACCF, M_WAITOK | 305 M_ZERO); 306 if (afp->accf_create != NULL && afa.af_name[0] != '\0') { 307 int len = strlen(afa.af_name) + 1; 308 MALLOC(newaf->so_accept_filter_str, char *, len, M_ACCF, 309 M_WAITOK); 310 strcpy(newaf->so_accept_filter_str, afa.af_name); 311 } 312 313 /* 314 * Require a listen socket; don't try to replace an existing filter 315 * without first removing it. 316 */ 317 SOCK_LOCK(so); 318 if (((so->so_options & SO_ACCEPTCONN) == 0) || 319 (so->so_accf != NULL)) { 320 error = EINVAL; 321 goto out; 322 } 323 324 /* 325 * Invoke the accf_create() method of the filter if required. The 326 * socket mutex is held over this call, so create methods for filters 327 * can't block. 328 */ 329 if (afp->accf_create != NULL) { 330 newaf->so_accept_filter_arg = 331 afp->accf_create(so, afa.af_arg); 332 if (newaf->so_accept_filter_arg == NULL) { 333 error = EINVAL; 334 goto out; 335 } 336 } 337 newaf->so_accept_filter = afp; 338 so->so_accf = newaf; 339 so->so_options |= SO_ACCEPTFILTER; 340 newaf = NULL; 341 out: 342 SOCK_UNLOCK(so); 343 if (newaf != NULL) { 344 if (newaf->so_accept_filter_str != NULL) 345 FREE(newaf->so_accept_filter_str, M_ACCF); 346 FREE(newaf, M_ACCF); 347 } 348 return (error); 349 } 350
Indexes created Mon Oct 13 16:09:52 GMT 2025