qdisc.c revision 8a3efffa5b3fde252675239914118664d36a2c24
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) 2003-2008 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, struct nl_parser_param *pp) 100{ 101 int err; 102 struct rtnl_qdisc *qdisc; 103 struct rtnl_qdisc_ops *qops; 104 105 qdisc = rtnl_qdisc_alloc(); 106 if (!qdisc) { 107 err = -NLE_NOMEM; 108 goto errout; 109 } 110 111 qdisc->ce_msgtype = n->nlmsg_type; 112 113 err = tca_msg_parser(n, (struct rtnl_tca *) qdisc); 114 if (err < 0) 115 goto errout_free; 116 117 qops = rtnl_qdisc_lookup_ops(qdisc); 118 if (qops && qops->qo_msg_parser) { 119 err = qops->qo_msg_parser(qdisc); 120 if (err < 0) 121 goto errout_free; 122 } 123 124 err = pp->pp_cb((struct nl_object *) qdisc, pp); 125 if (err < 0) 126 goto errout_free; 127 128 err = P_ACCEPT; 129 130errout_free: 131 rtnl_qdisc_put(qdisc); 132errout: 133 return err; 134} 135 136static int qdisc_request_update(struct nl_cache *c, struct nl_handle *h) 137{ 138 struct tcmsg tchdr = { 139 .tcm_family = AF_UNSPEC, 140 .tcm_ifindex = c->c_iarg1, 141 }; 142 143 return nl_send_simple(h, RTM_GETQDISC, NLM_F_DUMP, &tchdr, 144 sizeof(tchdr)); 145} 146 147/** 148 * @name QDisc Addition 149 * @{ 150 */ 151 152static int qdisc_build(struct rtnl_qdisc *qdisc, int type, int flags, 153 struct nl_msg **result) 154{ 155 struct rtnl_qdisc_ops *qops; 156 int err; 157 158 err = tca_build_msg((struct rtnl_tca *) qdisc, type, flags, result); 159 if (err < 0) 160 return err; 161 162 qops = rtnl_qdisc_lookup_ops(qdisc); 163 if (qops && qops->qo_get_opts) { 164 struct nl_msg *opts; 165 166 opts = qops->qo_get_opts(qdisc); 167 if (opts) { 168 err = nla_put_nested(*result, TCA_OPTIONS, opts); 169 nlmsg_free(opts); 170 if (err < 0) 171 goto errout; 172 } 173 } 174 /* Some qdiscs don't accept properly nested messages (e.g. netem). To 175 * accomodate for this, they can complete the message themselves. 176 */ 177 else if (qops && qops->qo_build_msg) { 178 err = qops->qo_build_msg(qdisc, *result); 179 if (err < 0) 180 goto errout; 181 } 182 183 return 0; 184errout: 185 nlmsg_free(*result); 186 187 return err; 188} 189 190/** 191 * Build a netlink message to add a new qdisc 192 * @arg qdisc qdisc to add 193 * @arg flags additional netlink message flags 194 * @arg result Pointer to store resulting message. 195 * 196 * Builds a new netlink message requesting an addition of a qdisc. 197 * The netlink message header isn't fully equipped with all relevant 198 * fields and must be sent out via nl_send_auto_complete() or 199 * supplemented as needed. 200 * 201 * Common message flags used: 202 * - NLM_F_REPLACE - replace a potential existing qdisc 203 * 204 * @return 0 on success or a negative error code. 205 */ 206int rtnl_qdisc_build_add_request(struct rtnl_qdisc *qdisc, int flags, 207 struct nl_msg **result) 208{ 209 return qdisc_build(qdisc, RTM_NEWQDISC, NLM_F_CREATE | flags, result); 210} 211 212/** 213 * Add a new qdisc 214 * @arg handle netlink handle 215 * @arg qdisc qdisc to delete 216 * @arg flags additional netlink message flags 217 * 218 * Builds a netlink message by calling rtnl_qdisc_build_add_request(), 219 * sends the request to the kernel and waits for the ACK to be 220 * received and thus blocks until the request has been processed. 221 * 222 * Common message flags used: 223 * - NLM_F_REPLACE - replace a potential existing qdisc 224 * 225 * @return 0 on success or a negative error code 226 */ 227int rtnl_qdisc_add(struct nl_handle *handle, struct rtnl_qdisc *qdisc, 228 int flags) 229{ 230 struct nl_msg *msg; 231 int err; 232 233 if ((err = rtnl_qdisc_build_add_request(qdisc, flags, &msg)) < 0) 234 return err; 235 236 if ((err = nl_send_auto_complete(handle, msg)) < 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 * @arg result Pointer to store resulting message. 255 * 256 * Builds a new netlink message requesting an change of qdisc 257 * attributes. The netlink message header isn't fully equipped 258 * with all relevant fields and must be sent out via 259 * nl_send_auto_complete() or supplemented as needed. 260 * 261 * @return 0 on success or a negative error code. 262 */ 263int rtnl_qdisc_build_change_request(struct rtnl_qdisc *qdisc, 264 struct rtnl_qdisc *new, 265 struct nl_msg **result) 266{ 267 return qdisc_build(qdisc, RTM_NEWQDISC, NLM_F_REPLACE, result); 268} 269 270/** 271 * Change attributes of a qdisc 272 * @arg handle netlink handle 273 * @arg qdisc qdisc to change 274 * @arg new new qdisc attributes 275 * 276 * Builds a netlink message by calling rtnl_qdisc_build_change_request(), 277 * sends the request to the kernel and waits for the ACK to be 278 * received and thus blocks until the request has been processed. 279 * 280 * @return 0 on success or a negative error code 281 */ 282int rtnl_qdisc_change(struct nl_handle *handle, struct rtnl_qdisc *qdisc, 283 struct rtnl_qdisc *new) 284{ 285 struct nl_msg *msg; 286 int err; 287 288 if ((err = rtnl_qdisc_build_change_request(qdisc, new, &msg)) < 0) 289 return err; 290 291 if ((err = nl_send_auto_complete(handle, msg)) < 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 * @arg result Pointer to store resulting message. 309 * 310 * Builds a new netlink message requesting a deletion of a qdisc. 311 * The netlink message header isn't fully equipped with all relevant 312 * fields and must thus be sent out via nl_send_auto_complete() 313 * or supplemented as needed. 314 * 315 * @return 0 on success or a negative error code. 316 */ 317int rtnl_qdisc_build_delete_request(struct rtnl_qdisc *qdisc, 318 struct nl_msg **result) 319{ 320 struct nl_msg *msg; 321 struct tcmsg tchdr; 322 int required = TCA_ATTR_IFINDEX | TCA_ATTR_PARENT; 323 324 if ((qdisc->ce_mask & required) != required) 325 BUG(); 326 327 msg = nlmsg_alloc_simple(RTM_DELQDISC, 0); 328 if (!msg) 329 return -NLE_NOMEM; 330 331 tchdr.tcm_family = AF_UNSPEC; 332 tchdr.tcm_handle = qdisc->q_handle; 333 tchdr.tcm_parent = qdisc->q_parent; 334 tchdr.tcm_ifindex = qdisc->q_ifindex; 335 if (nlmsg_append(msg, &tchdr, sizeof(tchdr), NLMSG_ALIGNTO) < 0) { 336 nlmsg_free(msg); 337 return -NLE_MSGSIZE; 338 } 339 340 *result = msg; 341 return 0; 342} 343 344/** 345 * Delete a qdisc 346 * @arg handle netlink handle 347 * @arg qdisc qdisc to delete 348 * 349 * Builds a netlink message by calling rtnl_qdisc_build_delete_request(), 350 * sends the request to the kernel and waits for the ACK to be 351 * received and thus blocks until the request has been processed. 352 * 353 * @return 0 on success or a negative error code 354 */ 355int rtnl_qdisc_delete(struct nl_handle *handle, struct rtnl_qdisc *qdisc) 356{ 357 struct nl_msg *msg; 358 int err; 359 360 if ((err = rtnl_qdisc_build_delete_request(qdisc, &msg)) < 0) 361 return err; 362 363 if ((err = nl_send_auto_complete(handle, msg)) < 0) 364 return err; 365 366 nlmsg_free(msg); 367 return nl_wait_for_ack(handle); 368} 369 370/** @} */ 371 372/** 373 * @name Qdisc Cache Management 374 * @{ 375 */ 376 377/** 378 * Build a qdisc cache including all qdiscs currently configured in 379 * the kernel 380 * @arg sock netlink handle 381 * @arg result Pointer to store resulting message. 382 * 383 * Allocates a new cache, initializes it properly and updates it to 384 * include all qdiscs currently configured in the kernel. 385 * 386 * @return 0 on success or a negative error code. 387 */ 388int rtnl_qdisc_alloc_cache(struct nl_handle *sock, struct nl_cache **result) 389{ 390 return nl_cache_alloc_and_fill(&rtnl_qdisc_ops, sock, result); 391} 392 393/** 394 * Look up qdisc by its parent in the provided cache 395 * @arg cache qdisc cache 396 * @arg ifindex interface the qdisc is attached to 397 * @arg parent parent handle 398 * @return pointer to qdisc inside the cache or NULL if no match was found. 399 */ 400struct rtnl_qdisc * rtnl_qdisc_get_by_parent(struct nl_cache *cache, 401 int ifindex, uint32_t parent) 402{ 403 struct rtnl_qdisc *q; 404 405 if (cache->c_ops != &rtnl_qdisc_ops) 406 return NULL; 407 408 nl_list_for_each_entry(q, &cache->c_items, ce_list) { 409 if (q->q_parent == parent && q->q_ifindex == ifindex) { 410 nl_object_get((struct nl_object *) q); 411 return q; 412 } 413 } 414 415 return NULL; 416} 417 418/** 419 * Look up qdisc by its handle in the provided cache 420 * @arg cache qdisc cache 421 * @arg ifindex interface the qdisc is attached to 422 * @arg handle qdisc handle 423 * @return pointer to qdisc inside the cache or NULL if no match was found. 424 */ 425struct rtnl_qdisc * rtnl_qdisc_get(struct nl_cache *cache, 426 int ifindex, uint32_t handle) 427{ 428 struct rtnl_qdisc *q; 429 430 if (cache->c_ops != &rtnl_qdisc_ops) 431 return NULL; 432 433 nl_list_for_each_entry(q, &cache->c_items, ce_list) { 434 if (q->q_handle == handle && q->q_ifindex == ifindex) { 435 nl_object_get((struct nl_object *) q); 436 return q; 437 } 438 } 439 440 return NULL; 441} 442 443/** @} */ 444 445static struct nl_cache_ops rtnl_qdisc_ops = { 446 .co_name = "route/qdisc", 447 .co_hdrsize = sizeof(struct tcmsg), 448 .co_msgtypes = { 449 { RTM_NEWQDISC, NL_ACT_NEW, "new" }, 450 { RTM_DELQDISC, NL_ACT_DEL, "del" }, 451 { RTM_GETQDISC, NL_ACT_GET, "get" }, 452 END_OF_MSGTYPES_LIST, 453 }, 454 .co_protocol = NETLINK_ROUTE, 455 .co_request_update = qdisc_request_update, 456 .co_msg_parser = qdisc_msg_parser, 457 .co_obj_ops = &qdisc_obj_ops, 458}; 459 460static void __init qdisc_init(void) 461{ 462 nl_cache_mngt_register(&rtnl_qdisc_ops); 463} 464 465static void __exit qdisc_exit(void) 466{ 467 nl_cache_mngt_unregister(&rtnl_qdisc_ops); 468} 469 470/** @} */ 471