1// SPDX-License-Identifier: GPL-2.0 2/* Copyright (C) 2011-2020 B.A.T.M.A.N. contributors: 3 * 4 * Linus Lüssing, Marek Lindner 5 */ 6 7#include "bat_v_elp.h" 8#include "main.h" 9 10#include <linux/atomic.h> 11#include <linux/bitops.h> 12#include <linux/byteorder/generic.h> 13#include <linux/errno.h> 14#include <linux/etherdevice.h> 15#include <linux/ethtool.h> 16#include <linux/gfp.h> 17#include <linux/if_ether.h> 18#include <linux/jiffies.h> 19#include <linux/kernel.h> 20#include <linux/kref.h> 21#include <linux/netdevice.h> 22#include <linux/nl80211.h> 23#include <linux/prandom.h> 24#include <linux/random.h> 25#include <linux/rculist.h> 26#include <linux/rcupdate.h> 27#include <linux/rtnetlink.h> 28#include <linux/skbuff.h> 29#include <linux/stddef.h> 30#include <linux/string.h> 31#include <linux/types.h> 32#include <linux/workqueue.h> 33#include <net/cfg80211.h> 34#include <uapi/linux/batadv_packet.h> 35 36#include "bat_algo.h" 37#include "bat_v_ogm.h" 38#include "hard-interface.h" 39#include "log.h" 40#include "originator.h" 41#include "routing.h" 42#include "send.h" 43 44/** 45 * batadv_v_elp_start_timer() - restart timer for ELP periodic work 46 * @hard_iface: the interface for which the timer has to be reset 47 */ 48static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) 49{ 50 unsigned int msecs; 51 52 msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER; 53 msecs += prandom_u32_max(2 * BATADV_JITTER); 54 55 queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq, 56 msecs_to_jiffies(msecs)); 57} 58 59/** 60 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour 61 * @neigh: the neighbour for which the throughput has to be obtained 62 * 63 * Return: The throughput towards the given neighbour in multiples of 100kpbs 64 * (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc). 65 */ 66static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) 67{ 68 struct batadv_hard_iface *hard_iface = neigh->if_incoming; 69 struct ethtool_link_ksettings link_settings; 70 struct net_device *real_netdev; 71 struct station_info sinfo; 72 u32 throughput; 73 int ret; 74 75 /* if the user specified a customised value for this interface, then 76 * return it directly 77 */ 78 throughput = atomic_read(&hard_iface->bat_v.throughput_override); 79 if (throughput != 0) 80 return throughput; 81 82 /* if this is a wireless device, then ask its throughput through 83 * cfg80211 API 84 */ 85 if (batadv_is_wifi_hardif(hard_iface)) { 86 if (!batadv_is_cfg80211_hardif(hard_iface)) 87 /* unsupported WiFi driver version */ 88 goto default_throughput; 89 90 real_netdev = batadv_get_real_netdev(hard_iface->net_dev); 91 if (!real_netdev) 92 goto default_throughput; 93 94 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo); 95 96 if (!ret) { 97 /* free the TID stats immediately */ 98 cfg80211_sinfo_release_content(&sinfo); 99 } 100 101 dev_put(real_netdev); 102 if (ret == -ENOENT) { 103 /* Node is not associated anymore! It would be 104 * possible to delete this neighbor. For now set 105 * the throughput metric to 0. 106 */ 107 return 0; 108 } 109 if (ret) 110 goto default_throughput; 111 112 if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)) 113 return sinfo.expected_throughput / 100; 114 115 /* try to estimate the expected throughput based on reported tx 116 * rates 117 */ 118 if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE)) 119 return cfg80211_calculate_bitrate(&sinfo.txrate) / 3; 120 121 goto default_throughput; 122 } 123 124 /* if not a wifi interface, check if this device provides data via 125 * ethtool (e.g. an Ethernet adapter) 126 */ 127 memset(&link_settings, 0, sizeof(link_settings)); 128 rtnl_lock(); 129 ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings); 130 rtnl_unlock(); 131 if (ret == 0) { 132 /* link characteristics might change over time */ 133 if (link_settings.base.duplex == DUPLEX_FULL) 134 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX; 135 else 136 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX; 137 138 throughput = link_settings.base.speed; 139 if (throughput && throughput != SPEED_UNKNOWN) 140 return throughput * 10; 141 } 142 143default_throughput: 144 if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) { 145 batadv_info(hard_iface->soft_iface, 146 "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n", 147 hard_iface->net_dev->name, 148 BATADV_THROUGHPUT_DEFAULT_VALUE / 10, 149 BATADV_THROUGHPUT_DEFAULT_VALUE % 10); 150 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT; 151 } 152 153 /* if none of the above cases apply, return the base_throughput */ 154 return BATADV_THROUGHPUT_DEFAULT_VALUE; 155} 156 157/** 158 * batadv_v_elp_throughput_metric_update() - worker updating the throughput 159 * metric of a single hop neighbour 160 * @work: the work queue item 161 */ 162void batadv_v_elp_throughput_metric_update(struct work_struct *work) 163{ 164 struct batadv_hardif_neigh_node_bat_v *neigh_bat_v; 165 struct batadv_hardif_neigh_node *neigh; 166 167 neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v, 168 metric_work); 169 neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node, 170 bat_v); 171 172 ewma_throughput_add(&neigh->bat_v.throughput, 173 batadv_v_elp_get_throughput(neigh)); 174 175 /* decrement refcounter to balance increment performed before scheduling 176 * this task 177 */ 178 batadv_hardif_neigh_put(neigh); 179} 180 181/** 182 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour 183 * @neigh: the neighbour to probe 184 * 185 * Sends a predefined number of unicast wifi packets to a given neighbour in 186 * order to trigger the throughput estimation on this link by the RC algorithm. 187 * Packets are sent only if there is not enough payload unicast traffic towards 188 * this neighbour.. 189 * 190 * Return: True on success and false in case of error during skb preparation. 191 */ 192static bool 193batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh) 194{ 195 struct batadv_hard_iface *hard_iface = neigh->if_incoming; 196 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); 197 unsigned long last_tx_diff; 198 struct sk_buff *skb; 199 int probe_len, i; 200 int elp_skb_len; 201 202 /* this probing routine is for Wifi neighbours only */ 203 if (!batadv_is_wifi_hardif(hard_iface)) 204 return true; 205 206 /* probe the neighbor only if no unicast packets have been sent 207 * to it in the last 100 milliseconds: this is the rate control 208 * algorithm sampling interval (minstrel). In this way, if not 209 * enough traffic has been sent to the neighbor, batman-adv can 210 * generate 2 probe packets and push the RC algorithm to perform 211 * the sampling 212 */ 213 last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx); 214 if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF) 215 return true; 216 217 probe_len = max_t(int, sizeof(struct batadv_elp_packet), 218 BATADV_ELP_MIN_PROBE_SIZE); 219 220 for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) { 221 elp_skb_len = hard_iface->bat_v.elp_skb->len; 222 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0, 223 probe_len - elp_skb_len, 224 GFP_ATOMIC); 225 if (!skb) 226 return false; 227 228 /* Tell the skb to get as big as the allocated space (we want 229 * the packet to be exactly of that size to make the link 230 * throughput estimation effective. 231 */ 232 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len); 233 234 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 235 "Sending unicast (probe) ELP packet on interface %s to %pM\n", 236 hard_iface->net_dev->name, neigh->addr); 237 238 batadv_send_skb_packet(skb, hard_iface, neigh->addr); 239 } 240 241 return true; 242} 243 244/** 245 * batadv_v_elp_periodic_work() - ELP periodic task per interface 246 * @work: work queue item 247 * 248 * Emits broadcast ELP messages in regular intervals. 249 */ 250static void batadv_v_elp_periodic_work(struct work_struct *work) 251{ 252 struct batadv_hardif_neigh_node *hardif_neigh; 253 struct batadv_hard_iface *hard_iface; 254 struct batadv_hard_iface_bat_v *bat_v; 255 struct batadv_elp_packet *elp_packet; 256 struct batadv_priv *bat_priv; 257 struct sk_buff *skb; 258 u32 elp_interval; 259 bool ret; 260 261 bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work); 262 hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v); 263 bat_priv = netdev_priv(hard_iface->soft_iface); 264 265 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) 266 goto out; 267 268 /* we are in the process of shutting this interface down */ 269 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE || 270 hard_iface->if_status == BATADV_IF_TO_BE_REMOVED) 271 goto out; 272 273 /* the interface was enabled but may not be ready yet */ 274 if (hard_iface->if_status != BATADV_IF_ACTIVE) 275 goto restart_timer; 276 277 skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC); 278 if (!skb) 279 goto restart_timer; 280 281 elp_packet = (struct batadv_elp_packet *)skb->data; 282 elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno)); 283 elp_interval = atomic_read(&hard_iface->bat_v.elp_interval); 284 elp_packet->elp_interval = htonl(elp_interval); 285 286 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 287 "Sending broadcast ELP packet on interface %s, seqno %u\n", 288 hard_iface->net_dev->name, 289 atomic_read(&hard_iface->bat_v.elp_seqno)); 290 291 batadv_send_broadcast_skb(skb, hard_iface); 292 293 atomic_inc(&hard_iface->bat_v.elp_seqno); 294 295 /* The throughput metric is updated on each sent packet. This way, if a 296 * node is dead and no longer sends packets, batman-adv is still able to 297 * react timely to its death. 298 * 299 * The throughput metric is updated by following these steps: 300 * 1) if the hard_iface is wifi => send a number of unicast ELPs for 301 * probing/sampling to each neighbor 302 * 2) update the throughput metric value of each neighbor (note that the 303 * value retrieved in this step might be 100ms old because the 304 * probing packets at point 1) could still be in the HW queue) 305 */ 306 rcu_read_lock(); 307 hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) { 308 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh)) 309 /* if something goes wrong while probing, better to stop 310 * sending packets immediately and reschedule the task 311 */ 312 break; 313 314 if (!kref_get_unless_zero(&hardif_neigh->refcount)) 315 continue; 316 317 /* Reading the estimated throughput from cfg80211 is a task that 318 * may sleep and that is not allowed in an rcu protected 319 * context. Therefore schedule a task for that. 320 */ 321 ret = queue_work(batadv_event_workqueue, 322 &hardif_neigh->bat_v.metric_work); 323 324 if (!ret) 325 batadv_hardif_neigh_put(hardif_neigh); 326 } 327 rcu_read_unlock(); 328 329restart_timer: 330 batadv_v_elp_start_timer(hard_iface); 331out: 332 return; 333} 334 335/** 336 * batadv_v_elp_iface_enable() - setup the ELP interface private resources 337 * @hard_iface: interface for which the data has to be prepared 338 * 339 * Return: 0 on success or a -ENOMEM in case of failure. 340 */ 341int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface) 342{ 343 static const size_t tvlv_padding = sizeof(__be32); 344 struct batadv_elp_packet *elp_packet; 345 unsigned char *elp_buff; 346 u32 random_seqno; 347 size_t size; 348 int res = -ENOMEM; 349 350 size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding; 351 hard_iface->bat_v.elp_skb = dev_alloc_skb(size); 352 if (!hard_iface->bat_v.elp_skb) 353 goto out; 354 355 skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN); 356 elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb, 357 BATADV_ELP_HLEN + tvlv_padding); 358 elp_packet = (struct batadv_elp_packet *)elp_buff; 359 360 elp_packet->packet_type = BATADV_ELP; 361 elp_packet->version = BATADV_COMPAT_VERSION; 362 363 /* randomize initial seqno to avoid collision */ 364 get_random_bytes(&random_seqno, sizeof(random_seqno)); 365 atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno); 366 367 /* assume full-duplex by default */ 368 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX; 369 370 /* warn the user (again) if there is no throughput data is available */ 371 hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT; 372 373 if (batadv_is_wifi_hardif(hard_iface)) 374 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX; 375 376 INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq, 377 batadv_v_elp_periodic_work); 378 batadv_v_elp_start_timer(hard_iface); 379 res = 0; 380 381out: 382 return res; 383} 384 385/** 386 * batadv_v_elp_iface_disable() - release ELP interface private resources 387 * @hard_iface: interface for which the resources have to be released 388 */ 389void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface) 390{ 391 cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq); 392 393 dev_kfree_skb(hard_iface->bat_v.elp_skb); 394 hard_iface->bat_v.elp_skb = NULL; 395} 396 397/** 398 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given 399 * hard-interface 400 * @primary_iface: the new primary interface 401 * @hard_iface: interface holding the to-be-updated buffer 402 */ 403void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface, 404 struct batadv_hard_iface *hard_iface) 405{ 406 struct batadv_elp_packet *elp_packet; 407 struct sk_buff *skb; 408 409 if (!hard_iface->bat_v.elp_skb) 410 return; 411 412 skb = hard_iface->bat_v.elp_skb; 413 elp_packet = (struct batadv_elp_packet *)skb->data; 414 ether_addr_copy(elp_packet->orig, 415 primary_iface->net_dev->dev_addr); 416} 417 418/** 419 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new 420 * primary interface 421 * @primary_iface: the new primary interface 422 */ 423void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface) 424{ 425 struct batadv_hard_iface *hard_iface; 426 427 /* update orig field of every elp iface belonging to this mesh */ 428 rcu_read_lock(); 429 list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) { 430 if (primary_iface->soft_iface != hard_iface->soft_iface) 431 continue; 432 433 batadv_v_elp_iface_activate(primary_iface, hard_iface); 434 } 435 rcu_read_unlock(); 436} 437 438/** 439 * batadv_v_elp_neigh_update() - update an ELP neighbour node 440 * @bat_priv: the bat priv with all the soft interface information 441 * @neigh_addr: the neighbour interface address 442 * @if_incoming: the interface the packet was received through 443 * @elp_packet: the received ELP packet 444 * 445 * Updates the ELP neighbour node state with the data received within the new 446 * ELP packet. 447 */ 448static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv, 449 u8 *neigh_addr, 450 struct batadv_hard_iface *if_incoming, 451 struct batadv_elp_packet *elp_packet) 452 453{ 454 struct batadv_neigh_node *neigh; 455 struct batadv_orig_node *orig_neigh; 456 struct batadv_hardif_neigh_node *hardif_neigh; 457 s32 seqno_diff; 458 s32 elp_latest_seqno; 459 460 orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig); 461 if (!orig_neigh) 462 return; 463 464 neigh = batadv_neigh_node_get_or_create(orig_neigh, 465 if_incoming, neigh_addr); 466 if (!neigh) 467 goto orig_free; 468 469 hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr); 470 if (!hardif_neigh) 471 goto neigh_free; 472 473 elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno; 474 seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno; 475 476 /* known or older sequence numbers are ignored. However always adopt 477 * if the router seems to have been restarted. 478 */ 479 if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE) 480 goto hardif_free; 481 482 neigh->last_seen = jiffies; 483 hardif_neigh->last_seen = jiffies; 484 hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno); 485 hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval); 486 487hardif_free: 488 if (hardif_neigh) 489 batadv_hardif_neigh_put(hardif_neigh); 490neigh_free: 491 if (neigh) 492 batadv_neigh_node_put(neigh); 493orig_free: 494 if (orig_neigh) 495 batadv_orig_node_put(orig_neigh); 496} 497 498/** 499 * batadv_v_elp_packet_recv() - main ELP packet handler 500 * @skb: the received packet 501 * @if_incoming: the interface this packet was received through 502 * 503 * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly 504 * processed or NET_RX_DROP in case of failure. 505 */ 506int batadv_v_elp_packet_recv(struct sk_buff *skb, 507 struct batadv_hard_iface *if_incoming) 508{ 509 struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface); 510 struct batadv_elp_packet *elp_packet; 511 struct batadv_hard_iface *primary_if; 512 struct ethhdr *ethhdr; 513 bool res; 514 int ret = NET_RX_DROP; 515 516 res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN); 517 if (!res) 518 goto free_skb; 519 520 ethhdr = eth_hdr(skb); 521 if (batadv_is_my_mac(bat_priv, ethhdr->h_source)) 522 goto free_skb; 523 524 /* did we receive a B.A.T.M.A.N. V ELP packet on an interface 525 * that does not have B.A.T.M.A.N. V ELP enabled ? 526 */ 527 if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0) 528 goto free_skb; 529 530 elp_packet = (struct batadv_elp_packet *)skb->data; 531 532 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 533 "Received ELP packet from %pM seqno %u ORIG: %pM\n", 534 ethhdr->h_source, ntohl(elp_packet->seqno), 535 elp_packet->orig); 536 537 primary_if = batadv_primary_if_get_selected(bat_priv); 538 if (!primary_if) 539 goto free_skb; 540 541 batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming, 542 elp_packet); 543 544 ret = NET_RX_SUCCESS; 545 batadv_hardif_put(primary_if); 546 547free_skb: 548 if (ret == NET_RX_SUCCESS) 549 consume_skb(skb); 550 else 551 kfree_skb(skb); 552 553 return ret; 554} 555