1 /*- 2 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org> 3 * Copyright (c) 2010 The FreeBSD Foundation 4 * All rights reserved. 5 * 6 * This software was developed by Lawrence Stewart while studying at the Centre 7 * for Advanced Internet Architectures, Swinburne University, made possible in 8 * part by grants from the FreeBSD Foundation and Cisco University Research 9 * Program Fund at Community Foundation Silicon Valley. 10 * 11 * Portions of this software were developed at the Centre for Advanced 12 * Internet Architectures, Swinburne University of Technology, Melbourne, 13 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/kernel.h> 42 #include <sys/hhook.h> 43 #include <sys/khelp.h> 44 #include <sys/malloc.h> 45 #include <sys/module.h> 46 #include <sys/module_khelp.h> 47 #include <sys/osd.h> 48 #include <sys/queue.h> 49 #include <sys/refcount.h> 50 #include <sys/systm.h> 51 52 #include <net/vnet.h> 53 54 struct hhook { 55 hhook_func_t hhk_func; 56 struct helper *hhk_helper; 57 void *hhk_udata; 58 STAILQ_ENTRY(hhook) hhk_next; 59 }; 60 61 MALLOC_DECLARE(M_HHOOK); 62 MALLOC_DEFINE(M_HHOOK, "hhook", "Helper hooks are linked off hhook_head lists"); 63 64 LIST_HEAD(hhookheadhead, hhook_head); 65 VNET_DEFINE(struct hhookheadhead, hhook_head_list); 66 #define V_hhook_head_list VNET(hhook_head_list) 67 68 static struct mtx hhook_head_list_lock; 69 MTX_SYSINIT(hhookheadlistlock, &hhook_head_list_lock, "hhook_head list lock", 70 MTX_DEF); 71 72 /* Private function prototypes. */ 73 static void hhook_head_destroy(struct hhook_head *hhh); 74 75 #define HHHLIST_LOCK() mtx_lock(&hhook_head_list_lock) 76 #define HHHLIST_UNLOCK() mtx_unlock(&hhook_head_list_lock) 77 #define HHHLIST_LOCK_ASSERT() mtx_assert(&hhook_head_list_lock, MA_OWNED) 78 79 #define HHH_LOCK_INIT(hhh) rm_init(&(hhh)->hhh_lock, "hhook_head rm lock") 80 #define HHH_LOCK_DESTROY(hhh) rm_destroy(&(hhh)->hhh_lock) 81 #define HHH_WLOCK(hhh) rm_wlock(&(hhh)->hhh_lock) 82 #define HHH_WUNLOCK(hhh) rm_wunlock(&(hhh)->hhh_lock) 83 #define HHH_RLOCK(hhh, rmpt) rm_rlock(&(hhh)->hhh_lock, (rmpt)) 84 #define HHH_RUNLOCK(hhh, rmpt) rm_runlock(&(hhh)->hhh_lock, (rmpt)) 85 86 /* 87 * Run all helper hook functions for a given hook point. 88 */ 89 void 90 hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd) 91 { 92 struct hhook *hhk; 93 void *hdata; 94 struct rm_priotracker rmpt; 95 96 KASSERT(hhh->hhh_refcount > 0, ("hhook_head %p refcount is 0", hhh)); 97 98 HHH_RLOCK(hhh, &rmpt); 99 STAILQ_FOREACH(hhk, &hhh->hhh_hooks, hhk_next) { 100 if (hhk->hhk_helper->h_flags & HELPER_NEEDS_OSD) { 101 hdata = osd_get(OSD_KHELP, hosd, hhk->hhk_helper->h_id); 102 if (hdata == NULL) 103 continue; 104 } else 105 hdata = NULL; 106 107 /* 108 * XXXLAS: We currently ignore the int returned by the hook, 109 * but will likely want to handle it in future to allow hhook to 110 * be used like pfil and effect changes at the hhook calling 111 * site e.g. we could define a new hook type of HHOOK_TYPE_PFIL 112 * and standardise what particular return values mean and set 113 * the context data to pass exactly the same information as pfil 114 * hooks currently receive, thus replicating pfil with hhook. 115 */ 116 hhk->hhk_func(hhh->hhh_type, hhh->hhh_id, hhk->hhk_udata, 117 ctx_data, hdata, hosd); 118 } 119 HHH_RUNLOCK(hhh, &rmpt); 120 } 121 122 /* 123 * Register a new helper hook function with a helper hook point. 124 */ 125 int 126 hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, uint32_t flags) 127 { 128 struct hhook *hhk, *tmp; 129 int error; 130 131 error = 0; 132 133 if (hhh == NULL) 134 return (ENOENT); 135 136 hhk = malloc(sizeof(struct hhook), M_HHOOK, 137 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT)); 138 139 if (hhk == NULL) 140 return (ENOMEM); 141 142 hhk->hhk_helper = hki->hook_helper; 143 hhk->hhk_func = hki->hook_func; 144 hhk->hhk_udata = hki->hook_udata; 145 146 HHH_WLOCK(hhh); 147 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) { 148 if (tmp->hhk_func == hki->hook_func && 149 tmp->hhk_udata == hki->hook_udata) { 150 /* The helper hook function is already registered. */ 151 error = EEXIST; 152 break; 153 } 154 } 155 156 if (!error) { 157 STAILQ_INSERT_TAIL(&hhh->hhh_hooks, hhk, hhk_next); 158 hhh->hhh_nhooks++; 159 } else 160 free(hhk, M_HHOOK); 161 162 HHH_WUNLOCK(hhh); 163 164 return (error); 165 } 166 167 /* 168 * Lookup a helper hook point and register a new helper hook function with it. 169 */ 170 int 171 hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags) 172 { 173 struct hhook_head *hhh; 174 int error; 175 176 hhh = hhook_head_get(hki->hook_type, hki->hook_id); 177 178 if (hhh == NULL) 179 return (ENOENT); 180 181 error = hhook_add_hook(hhh, hki, flags); 182 hhook_head_release(hhh); 183 184 return (error); 185 } 186 187 /* 188 * Remove a helper hook function from a helper hook point. 189 */ 190 int 191 hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki) 192 { 193 struct hhook *tmp; 194 195 if (hhh == NULL) 196 return (ENOENT); 197 198 HHH_WLOCK(hhh); 199 STAILQ_FOREACH(tmp, &hhh->hhh_hooks, hhk_next) { 200 if (tmp->hhk_func == hki->hook_func && 201 tmp->hhk_udata == hki->hook_udata) { 202 STAILQ_REMOVE(&hhh->hhh_hooks, tmp, hhook, hhk_next); 203 free(tmp, M_HHOOK); 204 hhh->hhh_nhooks--; 205 break; 206 } 207 } 208 HHH_WUNLOCK(hhh); 209 210 return (0); 211 } 212 213 /* 214 * Lookup a helper hook point and remove a helper hook function from it. 215 */ 216 int 217 hhook_remove_hook_lookup(struct hookinfo *hki) 218 { 219 struct hhook_head *hhh; 220 221 hhh = hhook_head_get(hki->hook_type, hki->hook_id); 222 223 if (hhh == NULL) 224 return (ENOENT); 225 226 hhook_remove_hook(hhh, hki); 227 hhook_head_release(hhh); 228 229 return (0); 230 } 231 232 /* 233 * Register a new helper hook point. 234 */ 235 int 236 hhook_head_register(int32_t hhook_type, int32_t hhook_id, struct hhook_head **hhh, 237 uint32_t flags) 238 { 239 struct hhook_head *tmphhh; 240 241 tmphhh = hhook_head_get(hhook_type, hhook_id); 242 243 if (tmphhh != NULL) { 244 /* Hook point previously registered. */ 245 hhook_head_release(tmphhh); 246 return (EEXIST); 247 } 248 249 /* XXXLAS: Need to implement support for non-virtualised hooks. */ 250 if ((flags & HHOOK_HEADISINVNET) == 0) { 251 printf("%s: only vnet-style virtualised hooks can be used\n", 252 __func__); 253 return (EINVAL); 254 } 255 256 tmphhh = malloc(sizeof(struct hhook_head), M_HHOOK, 257 M_ZERO | ((flags & HHOOK_WAITOK) ? M_WAITOK : M_NOWAIT)); 258 259 if (tmphhh == NULL) 260 return (ENOMEM); 261 262 tmphhh->hhh_type = hhook_type; 263 tmphhh->hhh_id = hhook_id; 264 tmphhh->hhh_nhooks = 0; 265 STAILQ_INIT(&tmphhh->hhh_hooks); 266 HHH_LOCK_INIT(tmphhh); 267 268 if (hhh != NULL) 269 refcount_init(&tmphhh->hhh_refcount, 1); 270 else 271 refcount_init(&tmphhh->hhh_refcount, 0); 272 273 if (flags & HHOOK_HEADISINVNET) { 274 tmphhh->hhh_flags |= HHH_ISINVNET; 275 HHHLIST_LOCK(); 276 LIST_INSERT_HEAD(&V_hhook_head_list, tmphhh, hhh_next); 277 HHHLIST_UNLOCK(); 278 } else { 279 /* XXXLAS: Add tmphhh to the non-virtualised list. */ 280 } 281 282 *hhh = tmphhh; 283 284 return (0); 285 } 286 287 static void 288 hhook_head_destroy(struct hhook_head *hhh) 289 { 290 struct hhook *tmp, *tmp2; 291 292 HHHLIST_LOCK_ASSERT(); 293 294 LIST_REMOVE(hhh, hhh_next); 295 HHH_WLOCK(hhh); 296 STAILQ_FOREACH_SAFE(tmp, &hhh->hhh_hooks, hhk_next, tmp2) 297 free(tmp, M_HHOOK); 298 HHH_WUNLOCK(hhh); 299 HHH_LOCK_DESTROY(hhh); 300 free(hhh, M_HHOOK); 301 } 302 303 /* 304 * Remove a helper hook point. 305 */ 306 int 307 hhook_head_deregister(struct hhook_head *hhh) 308 { 309 int error; 310 311 error = 0; 312 313 HHHLIST_LOCK(); 314 if (hhh == NULL) 315 error = ENOENT; 316 else if (hhh->hhh_refcount > 1) 317 error = EBUSY; 318 else 319 hhook_head_destroy(hhh); 320 HHHLIST_UNLOCK(); 321 322 return (error); 323 } 324 325 /* 326 * Remove a helper hook point via a hhook_head lookup. 327 */ 328 int 329 hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id) 330 { 331 struct hhook_head *hhh; 332 int error; 333 334 hhh = hhook_head_get(hhook_type, hhook_id); 335 error = hhook_head_deregister(hhh); 336 337 if (error == EBUSY) 338 hhook_head_release(hhh); 339 340 return (error); 341 } 342 343 /* 344 * Lookup and return the hhook_head struct associated with the specified type 345 * and id, or NULL if not found. If found, the hhook_head's refcount is bumped. 346 */ 347 struct hhook_head * 348 hhook_head_get(int32_t hhook_type, int32_t hhook_id) 349 { 350 struct hhook_head *hhh; 351 352 /* XXXLAS: Pick hhook_head_list based on hhook_head flags. */ 353 HHHLIST_LOCK(); 354 LIST_FOREACH(hhh, &V_hhook_head_list, hhh_next) { 355 if (hhh->hhh_type == hhook_type && hhh->hhh_id == hhook_id) { 356 refcount_acquire(&hhh->hhh_refcount); 357 break; 358 } 359 } 360 HHHLIST_UNLOCK(); 361 362 return (hhh); 363 } 364 365 void 366 hhook_head_release(struct hhook_head *hhh) 367 { 368 369 refcount_release(&hhh->hhh_refcount); 370 } 371 372 /* 373 * Check the hhook_head private flags and return the appropriate public 374 * representation of the flag to the caller. The function is implemented in a 375 * way that allows us to cope with other subsystems becoming virtualised in the 376 * future. 377 */ 378 uint32_t 379 hhook_head_is_virtualised(struct hhook_head *hhh) 380 { 381 uint32_t ret; 382 383 ret = 0; 384 385 if (hhh != NULL) { 386 if (hhh->hhh_flags & HHH_ISINVNET) 387 ret = HHOOK_HEADISINVNET; 388 } 389 390 return (ret); 391 } 392 393 uint32_t 394 hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id) 395 { 396 struct hhook_head *hhh; 397 uint32_t ret; 398 399 hhh = hhook_head_get(hook_type, hook_id); 400 401 if (hhh == NULL) 402 return (0); 403 404 ret = hhook_head_is_virtualised(hhh); 405 hhook_head_release(hhh); 406 407 return (ret); 408 } 409 410 /* 411 * Vnet created and being initialised. 412 */ 413 static void 414 hhook_vnet_init(const void *unused __unused) 415 { 416 417 LIST_INIT(&V_hhook_head_list); 418 } 419 420 /* 421 * Vnet being torn down and destroyed. 422 */ 423 static void 424 hhook_vnet_uninit(const void *unused __unused) 425 { 426 struct hhook_head *hhh, *tmphhh; 427 428 /* 429 * If subsystems which export helper hook points use the hhook KPI 430 * correctly, the loop below should have no work to do because the 431 * subsystem should have already called hhook_head_deregister(). 432 */ 433 HHHLIST_LOCK(); 434 LIST_FOREACH_SAFE(hhh, &V_hhook_head_list, hhh_next, tmphhh) { 435 printf("%s: hhook_head type=%d, id=%d cleanup required\n", 436 __func__, hhh->hhh_type, hhh->hhh_id); 437 hhook_head_destroy(hhh); 438 } 439 HHHLIST_UNLOCK(); 440 } 441 442 443 /* 444 * When a vnet is created and being initialised, init the V_hhook_head_list. 445 */ 446 VNET_SYSINIT(hhook_vnet_init, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, 447 hhook_vnet_init, NULL); 448 449 /* 450 * The hhook KPI provides a mechanism for subsystems which export helper hook 451 * points to clean up on vnet tear down, but in case the KPI is misused, 452 * provide a function to clean up and free memory for a vnet being destroyed. 453 */ 454 VNET_SYSUNINIT(hhook_vnet_uninit, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, 455 hhook_vnet_uninit, NULL); 456