qdisc.c revision 44d362409d5469aed47d19e7908d19bd194493a4
1/* 2 * lib/route/qdisc.c Queueing Disciplines 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation version 2.1 7 * of the License. 8 * 9 * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch> 10 */ 11 12/** 13 * @ingroup tc 14 * @defgroup qdisc Queueing Disciplines 15 * 16 * @par Qdisc Handles 17 * In general, qdiscs are identified by the major part of a traffic control 18 * handle (the upper 16 bits). A few special values exist though: 19 * - \c TC_H_ROOT: root qdisc (directly attached to the device) 20 * - \c TC_H_INGRESS: ingress qdisc (directly attached to the device) 21 * - \c TC_H_UNSPEC: unspecified qdisc (no reference) 22 * 23 * @par 1) Adding a Qdisc 24 * @code 25 * // Allocate a new empty qdisc to be filled out 26 * struct rtnl_qdisc *qdisc = rtnl_qdisc_alloc(); 27 * 28 * // ... specify the kind of the Qdisc 29 * rtnl_qdisc_set_kind(qdisc, "pfifo"); 30 * 31 * // Specify the device the qdisc should be attached to 32 * rtnl_qdisc_set_ifindex(qdisc, ifindex); 33 * 34 * // ... specify the parent qdisc 35 * rtnl_qdisc_set_parent(qdisc, TC_H_ROOT); 36 * 37 * // Specifying the handle is not required but makes reidentifying easier 38 * // and may help to avoid adding a qdisc twice. 39 * rtnl_qdisc_set_handle(qdisc, 0x000A0000); 40 * 41 * // Now on to specify the qdisc specific options, see the relevant qdisc 42 * // modules for documentation, in this example we set the upper limit of 43 * // the packet fifo qdisc to 64 44 * rtnl_qdisc_fifo_set_limit(qdisc, 64); 45 * 46 * rtnl_qdisc_add(handle, qdisc, NLM_R_REPLACE); 47 * 48 * // Free up the memory 49 * rtnl_qdisc_put(qdisc); 50 * @endcode 51 * 52 * @par 2) Deleting a Qdisc 53 * @code 54 * // Allocate a new empty qdisc to be filled out with the parameters 55 * // specifying the qdisc to be deleted. Alternatively a fully equiped 56 * // Qdisc object from a cache can be used. 57 * struct rtnl_qdisc *qdisc = rtnl_qdisc_alloc(); 58 * 59 * // The interface index of the device the qdisc is on and the parent handle 60 * // are the least required fields to be filled out. 61 * // Note: Specify TC_H_ROOT or TC_H_INGRESS as parent handle to delete the 62 * // root respectively root ingress qdisc. 63 * rtnl_qdisc_set_ifindex(qdisc, ifindex); 64 * rtnl_qdisc_set_parent(qdisc, parent_handle); 65 * 66 * // If required for identification, the handle can be specified as well. 67 * rtnl_qdisc_set_handle(qdisc, qdisc_handle); 68 * 69 * // Not required but maybe helpful as sanity check, the kind of the qdisc 70 * // can be specified to avoid mistakes. 71 * rtnl_qdisc_set_kind(qdisc, "pfifo"); 72 * 73 * // Finally delete the qdisc with rtnl_qdisc_delete(), alternatively 74 * // rtnl_qdisc_build_delete_request() can be invoked to generate an 75 * // appropritate netlink message to send out. 76 * rtnl_qdisc_delete(handle, qdisc); 77 * 78 * // Free up the memory 79 * rtnl_qdisc_put(qdisc); 80 * @endcode 81 * 82 * @{ 83 */ 84 85#include <netlink-local.h> 86#include <netlink-tc.h> 87#include <netlink/netlink.h> 88#include <netlink/utils.h> 89#include <netlink/route/link.h> 90#include <netlink/route/tc.h> 91#include <netlink/route/qdisc.h> 92#include <netlink/route/class.h> 93#include <netlink/route/classifier.h> 94#include <netlink/route/qdisc-modules.h> 95 96static struct nl_cache_ops rtnl_qdisc_ops; 97 98static int qdisc_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who, 99 struct nlmsghdr *n, void *arg) 100{ 101 int err = -ENOMEM; 102 struct nl_parser_param *pp = arg; 103 struct rtnl_qdisc *qdisc; 104 struct rtnl_qdisc_ops *qops; 105 106 qdisc = rtnl_qdisc_alloc(); 107 if (!qdisc) { 108 err = nl_errno(ENOMEM); 109 goto errout; 110 } 111 112 qdisc->ce_msgtype = n->nlmsg_type; 113 114 err = tca_msg_parser(n, (struct rtnl_tca *) qdisc); 115 if (err < 0) 116 goto errout_free; 117 118 qops = rtnl_qdisc_lookup_ops(qdisc); 119 if (qops && qops->qo_msg_parser) { 120 err = qops->qo_msg_parser(qdisc); 121 if (err < 0) 122 goto errout_free; 123 } 124 125 err = pp->pp_cb((struct nl_object *) qdisc, pp); 126 if (err < 0) 127 goto errout_free; 128 129 return P_ACCEPT; 130 131errout_free: 132 rtnl_qdisc_put(qdisc); 133errout: 134 return err; 135} 136 137static int qdisc_request_update(struct nl_cache *c, struct nl_handle *h) 138{ 139 struct tcmsg tchdr = { 140 .tcm_family = AF_UNSPEC, 141 .tcm_ifindex = c->c_iarg1, 142 }; 143 144 return nl_send_simple(h, RTM_GETQDISC, NLM_F_DUMP, &tchdr, 145 sizeof(tchdr)); 146} 147 148/** 149 * @name QDisc Addition 150 * @{ 151 */ 152 153static struct nl_msg *qdisc_build(struct rtnl_qdisc *qdisc, int type, int flags) 154{ 155 struct rtnl_qdisc_ops *qops; 156 struct nl_msg *msg; 157 int err; 158 159 msg = tca_build_msg((struct rtnl_tca *) qdisc, type, flags); 160 if (!msg) 161 goto errout; 162 163 qops = rtnl_qdisc_lookup_ops(qdisc); 164 if (qops && qops->qo_get_opts) { 165 struct nl_msg *opts; 166 167 opts = qops->qo_get_opts(qdisc); 168 if (opts) { 169 err = nla_put_nested(msg, TCA_OPTIONS, opts); 170 nlmsg_free(opts); 171 if (err < 0) 172 goto errout; 173 } 174 } 175 176 return msg; 177errout: 178 nlmsg_free(msg); 179 180 return NULL; 181} 182 183/** 184 * Build a netlink message to add a new qdisc 185 * @arg qdisc qdisc to add 186 * @arg flags additional netlink message flags 187 * 188 * Builds a new netlink message requesting an addition of a qdisc. 189 * The netlink message header isn't fully equipped with all relevant 190 * fields and must be sent out via nl_send_auto_complete() or 191 * supplemented as needed. 192 * 193 * Common message flags used: 194 * - NLM_F_REPLACE - replace a potential existing qdisc 195 * 196 * @return New netlink message 197 */ 198struct nl_msg *rtnl_qdisc_build_add_request(struct rtnl_qdisc *qdisc, 199 int flags) 200{ 201 struct nl_msg *msg; 202 203 msg = qdisc_build(qdisc, RTM_NEWQDISC, NLM_F_CREATE | flags); 204 if (!msg) 205 nl_errno(ENOMEM); 206 207 return msg; 208} 209 210/** 211 * Add a new qdisc 212 * @arg handle netlink handle 213 * @arg qdisc qdisc to delete 214 * @arg flags additional netlink message flags 215 * 216 * Builds a netlink message by calling rtnl_qdisc_build_add_request(), 217 * sends the request to the kernel and waits for the ACK to be 218 * received and thus blocks until the request has been processed. 219 * 220 * Common message flags used: 221 * - NLM_F_REPLACE - replace a potential existing qdisc 222 * 223 * @return 0 on success or a negative error code 224 */ 225int rtnl_qdisc_add(struct nl_handle *handle, struct rtnl_qdisc *qdisc, 226 int flags) 227{ 228 struct nl_msg *msg; 229 int err; 230 231 msg = rtnl_qdisc_build_add_request(qdisc, flags); 232 if (!msg) 233 return nl_errno(ENOMEM); 234 235 err = nl_send_auto_complete(handle, msg); 236 if (err < 0) 237 return err; 238 239 nlmsg_free(msg); 240 return nl_wait_for_ack(handle); 241} 242 243/** @} */ 244 245/** 246 * @name QDisc Modification 247 * @{ 248 */ 249 250/** 251 * Build a netlink message to change attributes of a existing qdisc 252 * @arg qdisc qdisc to change 253 * @arg new new qdisc attributes 254 * 255 * Builds a new netlink message requesting an change of qdisc 256 * attributes. The netlink message header isn't fully equipped 257 * with all relevant fields and must be sent out via 258 * nl_send_auto_complete() or supplemented as needed. 259 * 260 * @return New netlink message 261 */ 262struct nl_msg *rtnl_qdisc_build_change_request(struct rtnl_qdisc *qdisc, 263 struct rtnl_qdisc *new) 264{ 265 return qdisc_build(qdisc, RTM_NEWQDISC, NLM_F_REPLACE); 266} 267 268/** 269 * Change attributes of a qdisc 270 * @arg handle netlink handle 271 * @arg qdisc qdisc to change 272 * @arg new new qdisc attributes 273 * 274 * Builds a netlink message by calling rtnl_qdisc_build_change_request(), 275 * sends the request to the kernel and waits for the ACK to be 276 * received and thus blocks until the request has been processed. 277 * 278 * @return 0 on success or a negative error code 279 */ 280int rtnl_qdisc_change(struct nl_handle *handle, struct rtnl_qdisc *qdisc, 281 struct rtnl_qdisc *new) 282{ 283 struct nl_msg *msg; 284 int err; 285 286 msg = rtnl_qdisc_build_change_request(qdisc, new); 287 if (!msg) 288 return nl_errno(ENOMEM); 289 290 err = nl_send_auto_complete(handle, msg); 291 if (err < 0) 292 return err; 293 294 nlmsg_free(msg); 295 return nl_wait_for_ack(handle); 296} 297 298/** @} */ 299 300/** 301 * @name QDisc Deletion 302 * @{ 303 */ 304 305/** 306 * Build a netlink request message to delete a qdisc 307 * @arg qdisc qdisc to delete 308 * 309 * Builds a new netlink message requesting a deletion of a qdisc. 310 * The netlink message header isn't fully equipped with all relevant 311 * fields and must thus be sent out via nl_send_auto_complete() 312 * or supplemented as needed. 313 * 314 * @return New netlink message 315 */ 316struct nl_msg *rtnl_qdisc_build_delete_request(struct rtnl_qdisc *qdisc) 317{ 318 struct nl_msg *msg; 319 struct tcmsg tchdr; 320 int required = TCA_ATTR_IFINDEX | TCA_ATTR_PARENT; 321 322 if ((qdisc->ce_mask & required) != required) 323 BUG(); 324 325 msg = nlmsg_alloc_simple(RTM_DELQDISC, 0); 326 if (!msg) 327 return NULL; 328 329 tchdr.tcm_family = AF_UNSPEC, 330 tchdr.tcm_handle = qdisc->q_handle, 331 tchdr.tcm_parent = qdisc->q_parent, 332 tchdr.tcm_ifindex = qdisc->q_ifindex, 333 nlmsg_append(msg, &tchdr, sizeof(tchdr), NLMSG_ALIGNTO); 334 335 return msg; 336} 337 338/** 339 * Delete a qdisc 340 * @arg handle netlink handle 341 * @arg qdisc qdisc to delete 342 * 343 * Builds a netlink message by calling rtnl_qdisc_build_delete_request(), 344 * sends the request to the kernel and waits for the ACK to be 345 * received and thus blocks until the request has been processed. 346 * 347 * @return 0 on success or a negative error code 348 */ 349int rtnl_qdisc_delete(struct nl_handle *handle, struct rtnl_qdisc *qdisc) 350{ 351 struct nl_msg *msg; 352 int err; 353 354 msg = rtnl_qdisc_build_delete_request(qdisc); 355 if (!msg) 356 return nl_errno(ENOMEM); 357 358 err = nl_send_auto_complete(handle, msg); 359 if (err < 0) 360 return err; 361 362 nlmsg_free(msg); 363 return nl_wait_for_ack(handle); 364} 365 366/** @} */ 367 368/** 369 * @name Qdisc Cache Management 370 * @{ 371 */ 372 373/** 374 * Build a qdisc cache including all qdiscs currently configured in 375 * the kernel 376 * @arg handle netlink handle 377 * 378 * Allocates a new cache, initializes it properly and updates it to 379 * include all qdiscs currently configured in the kernel. 380 * 381 * @note The caller is responsible for destroying and freeing the 382 * cache after using it. 383 * @return The cache or NULL if an error has occured. 384 */ 385struct nl_cache * rtnl_qdisc_alloc_cache(struct nl_handle *handle) 386{ 387 struct nl_cache * cache; 388 389 cache = nl_cache_alloc(&rtnl_qdisc_ops); 390 if (cache == NULL) 391 return NULL; 392 393 if (handle && nl_cache_refill(handle, cache) < 0) { 394 nl_cache_free(cache); 395 return NULL; 396 } 397 398 return cache; 399} 400 401/** 402 * Look up qdisc by its parent in the provided cache 403 * @arg cache qdisc cache 404 * @arg ifindex interface the qdisc is attached to 405 * @arg parent parent handle 406 * @return pointer to qdisc inside the cache or NULL if no match was found. 407 */ 408struct rtnl_qdisc * rtnl_qdisc_get_by_parent(struct nl_cache *cache, 409 int ifindex, uint32_t parent) 410{ 411 struct rtnl_qdisc *q; 412 413 if (cache->c_ops != &rtnl_qdisc_ops) 414 return NULL; 415 416 nl_list_for_each_entry(q, &cache->c_items, ce_list) { 417 if (q->q_parent == parent && q->q_ifindex == ifindex) { 418 nl_object_get((struct nl_object *) q); 419 return q; 420 } 421 } 422 423 return NULL; 424} 425 426/** 427 * Look up qdisc by its handle in the provided cache 428 * @arg cache qdisc cache 429 * @arg ifindex interface the qdisc is attached to 430 * @arg handle qdisc handle 431 * @return pointer to qdisc inside the cache or NULL if no match was found. 432 */ 433struct rtnl_qdisc * rtnl_qdisc_get(struct nl_cache *cache, 434 int ifindex, uint32_t handle) 435{ 436 struct rtnl_qdisc *q; 437 438 if (cache->c_ops != &rtnl_qdisc_ops) 439 return NULL; 440 441 nl_list_for_each_entry(q, &cache->c_items, ce_list) { 442 if (q->q_handle == handle && q->q_ifindex == ifindex) { 443 nl_object_get((struct nl_object *) q); 444 return q; 445 } 446 } 447 448 return NULL; 449} 450 451/** @} */ 452 453static struct nl_cache_ops rtnl_qdisc_ops = { 454 .co_name = "route/qdisc", 455 .co_hdrsize = sizeof(struct tcmsg), 456 .co_msgtypes = { 457 { RTM_NEWQDISC, NL_ACT_NEW, "new" }, 458 { RTM_DELQDISC, NL_ACT_DEL, "del" }, 459 { RTM_GETQDISC, NL_ACT_GET, "get" }, 460 END_OF_MSGTYPES_LIST, 461 }, 462 .co_protocol = NETLINK_ROUTE, 463 .co_request_update = qdisc_request_update, 464 .co_msg_parser = qdisc_msg_parser, 465 .co_obj_ops = &qdisc_obj_ops, 466}; 467 468static void __init qdisc_init(void) 469{ 470 nl_cache_mngt_register(&rtnl_qdisc_ops); 471} 472 473static void __exit qdisc_exit(void) 474{ 475 nl_cache_mngt_unregister(&rtnl_qdisc_ops); 476} 477 478/** @} */ 479