1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (C) 2011-2019 B.A.T.M.A.N. contributors: 3 * 4 * Linus Lüssing, Marek Lindner 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of version 2 of the GNU General Public 8 * License as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include "bat_v_elp.h" 20 #include "main.h" 21 22 #include <linux/atomic.h> 23 #include <linux/bitops.h> 24 #include <linux/byteorder/generic.h> 25 #include <linux/errno.h> 26 #include <linux/etherdevice.h> 27 #include <linux/ethtool.h> 28 #include <linux/gfp.h> 29 #include <linux/if_ether.h> 30 #include <linux/jiffies.h> 31 #include <linux/kernel.h> 32 #include <linux/kref.h> 33 #include <linux/netdevice.h> 34 #include <linux/nl80211.h> 35 #include <linux/random.h> 36 #include <linux/rculist.h> 37 #include <linux/rcupdate.h> 38 #include <linux/rtnetlink.h> 39 #include <linux/skbuff.h> 40 #include <linux/stddef.h> 41 #include <linux/string.h> 42 #include <linux/types.h> 43 #include <linux/workqueue.h> 44 #include <net/cfg80211.h> 45 #include <uapi/linux/batadv_packet.h> 46 47 #include "bat_algo.h" 48 #include "bat_v_ogm.h" 49 #include "hard-interface.h" 50 #include "log.h" 51 #include "originator.h" 52 #include "routing.h" 53 #include "send.h" 54 55 /** 56 * batadv_v_elp_start_timer() - restart timer for ELP periodic work 57 * @hard_iface: the interface for which the timer has to be reset 58 */ 59 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) 60 { 61 unsigned int msecs; 62 63 msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER; 64 msecs += prandom_u32() % (2 * BATADV_JITTER); 65 66 queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq, 67 msecs_to_jiffies(msecs)); 68 } 69 70 /** 71 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour 72 * @neigh: the neighbour for which the throughput has to be obtained 73 * 74 * Return: The throughput towards the given neighbour in multiples of 100kpbs 75 * (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc). 76 */ 77 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) 78 { 79 struct batadv_hard_iface *hard_iface = neigh->if_incoming; 80 struct ethtool_link_ksettings link_settings; 81 struct net_device *real_netdev; 82 struct station_info sinfo; 83 u32 throughput; 84 int ret; 85 86 /* if the user specified a customised value for this interface, then 87 * return it directly 88 */ 89 throughput = atomic_read(&hard_iface->bat_v.throughput_override); 90 if (throughput != 0) 91 return throughput; 92 93 /* if this is a wireless device, then ask its throughput through 94 * cfg80211 API 95 */ 96 if (batadv_is_wifi_hardif(hard_iface)) { 97 if (!batadv_is_cfg80211_hardif(hard_iface)) 98 /* unsupported WiFi driver version */ 99 goto default_throughput; 100 101 real_netdev = batadv_get_real_netdev(hard_iface->net_dev); 102 if (!real_netdev) 103 goto default_throughput; 104 105 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo); 106 107 /* free the TID stats immediately */ 108 cfg80211_sinfo_release_content(&sinfo); 109 110 dev_put(real_netdev); 111 if (ret == -ENOENT) { 112 /* Node is not associated anymore! It would be 113 * possible to delete this neighbor. For now set 114 * the throughput metric to 0. 115 */ 116 return 0; 117 } 118 if (ret) 119 goto default_throughput; 120 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT))) 121 goto default_throughput; 122 123 return sinfo.expected_throughput / 100; 124 } 125 126 /* if not a wifi interface, check if this device provides data via 127 * ethtool (e.g. an Ethernet adapter) 128 */ 129 memset(&link_settings, 0, sizeof(link_settings)); 130 rtnl_lock(); 131 ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings); 132 rtnl_unlock(); 133 134 /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc 135 * tend to initialize the interface throughput with some value for the 136 * sake of having a throughput number to export via ethtool. This 137 * exported throughput leaves batman-adv to conclude the interface 138 * throughput is genuine (reflecting reality), thus no measurements 139 * are necessary. 140 * 141 * Based on the observation that those interface types also tend to set 142 * the link auto-negotiation to 'off', batman-adv shall check this 143 * setting to differentiate between genuine link throughput information 144 * and placeholders installed by virtual interfaces. 145 */ 146 if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) { 147 /* link characteristics might change over time */ 148 if (link_settings.base.duplex == DUPLEX_FULL) 149 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX; 150 else 151 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX; 152 153 throughput = link_settings.base.speed; 154 if (throughput && throughput != SPEED_UNKNOWN) 155 return throughput * 10; 156 } 157 158 default_throughput: 159 if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) { 160 batadv_info(hard_iface->soft_iface, 161 "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", 162 hard_iface->net_dev->name, 163 BATADV_THROUGHPUT_DEFAULT_VALUE / 10, 164 BATADV_THROUGHPUT_DEFAULT_VALUE % 10); 165 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT; 166 } 167 168 /* if none of the above cases apply, return the base_throughput */ 169 return BATADV_THROUGHPUT_DEFAULT_VALUE; 170 } 171 172 /** 173 * batadv_v_elp_throughput_metric_update() - worker updating the throughput 174 * metric of a single hop neighbour 175 * @work: the work queue item 176 */ 177 void batadv_v_elp_throughput_metric_update(struct work_struct *work) 178 { 179 struct batadv_hardif_neigh_node_bat_v *neigh_bat_v; 180 struct batadv_hardif_neigh_node *neigh; 181 182 neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v, 183 metric_work); 184 neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node, 185 bat_v); 186 187 ewma_throughput_add(&neigh->bat_v.throughput, 188 batadv_v_elp_get_throughput(neigh)); 189 190 /* decrement refcounter to balance increment performed before scheduling 191 * this task 192 */ 193 batadv_hardif_neigh_put(neigh); 194 } 195 196 /** 197 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour 198 * @neigh: the neighbour to probe 199 * 200 * Sends a predefined number of unicast wifi packets to a given neighbour in 201 * order to trigger the throughput estimation on this link by the RC algorithm. 202 * Packets are sent only if there there is not enough payload unicast traffic 203 * towards this neighbour.. 204 * 205 * Return: True on success and false in case of error during skb preparation. 206 */ 207 static bool 208 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh) 209 { 210 struct batadv_hard_iface *hard_iface = neigh->if_incoming; 211 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); 212 unsigned long last_tx_diff; 213 struct sk_buff *skb; 214 int probe_len, i; 215 int elp_skb_len; 216 217 /* this probing routine is for Wifi neighbours only */ 218 if (!batadv_is_wifi_hardif(hard_iface)) 219 return true; 220 221 /* probe the neighbor only if no unicast packets have been sent 222 * to it in the last 100 milliseconds: this is the rate control 223 * algorithm sampling interval (minstrel). In this way, if not 224 * enough traffic has been sent to the neighbor, batman-adv can 225 * generate 2 probe packets and push the RC algorithm to perform 226 * the sampling 227 */ 228 last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx); 229 if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF) 230 return true; 231 232 probe_len = max_t(int, sizeof(struct batadv_elp_packet), 233 BATADV_ELP_MIN_PROBE_SIZE); 234 235 for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) { 236 elp_skb_len = hard_iface->bat_v.elp_skb->len; 237 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0, 238 probe_len - elp_skb_len, 239 GFP_ATOMIC); 240 if (!skb) 241 return false; 242 243 /* Tell the skb to get as big as the allocated space (we want 244 * the packet to be exactly of that size to make the link 245 * throughput estimation effective. 246 */ 247 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len); 248 249 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 250 "Sending unicast (probe) ELP packet on interface %s to %pM\n", 251 hard_iface->net_dev->name, neigh->addr); 252 253 batadv_send_skb_packet(skb, hard_iface, neigh->addr); 254 } 255 256 return true; 257 } 258 259 /** 260 * batadv_v_elp_periodic_work() - ELP periodic task per interface 261 * @work: work queue item 262 * 263 * Emits broadcast ELP message in regular intervals. 264 */ 265 static void batadv_v_elp_periodic_work(struct work_struct *work) 266 { 267 struct batadv_hardif_neigh_node *hardif_neigh; 268 struct batadv_hard_iface *hard_iface; 269 struct batadv_hard_iface_bat_v *bat_v; 270 struct batadv_elp_packet *elp_packet; 271 struct batadv_priv *bat_priv; 272 struct sk_buff *skb; 273 u32 elp_interval; 274 bool ret; 275 276 bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work); 277 hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v); 278 bat_priv = netdev_priv(hard_iface->soft_iface); 279 280 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) 281 goto out; 282 283 /* we are in the process of shutting this interface down */ 284 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE || 285 hard_iface->if_status == BATADV_IF_TO_BE_REMOVED) 286 goto out; 287 288 /* the interface was enabled but may not be ready yet */ 289 if (hard_iface->if_status != BATADV_IF_ACTIVE) 290 goto restart_timer; 291 292 skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC); 293 if (!skb) 294 goto restart_timer; 295 296 elp_packet = (struct batadv_elp_packet *)skb->data; 297 elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno)); 298 elp_interval = atomic_read(&hard_iface->bat_v.elp_interval); 299 elp_packet->elp_interval = htonl(elp_interval); 300 301 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 302 "Sending broadcast ELP packet on interface %s, seqno %u\n", 303 hard_iface->net_dev->name, 304 atomic_read(&hard_iface->bat_v.elp_seqno)); 305 306 batadv_send_broadcast_skb(skb, hard_iface); 307 308 atomic_inc(&hard_iface->bat_v.elp_seqno); 309 310 /* The throughput metric is updated on each sent packet. This way, if a 311 * node is dead and no longer sends packets, batman-adv is still able to 312 * react timely to its death. 313 * 314 * The throughput metric is updated by following these steps: 315 * 1) if the hard_iface is wifi => send a number of unicast ELPs for 316 * probing/sampling to each neighbor 317 * 2) update the throughput metric value of each neighbor (note that the 318 * value retrieved in this step might be 100ms old because the 319 * probing packets at point 1) could still be in the HW queue) 320 */ 321 rcu_read_lock(); 322 hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) { 323 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh)) 324 /* if something goes wrong while probing, better to stop 325 * sending packets immediately and reschedule the task 326 */ 327 break; 328 329 if (!kref_get_unless_zero(&hardif_neigh->refcount)) 330 continue; 331 332 /* Reading the estimated throughput from cfg80211 is a task that 333 * may sleep and that is not allowed in an rcu protected 334 * context. Therefore schedule a task for that. 335 */ 336 ret = queue_work(batadv_event_workqueue, 337 &hardif_neigh->bat_v.metric_work); 338 339 if (!ret) 340 batadv_hardif_neigh_put(hardif_neigh); 341 } 342 rcu_read_unlock(); 343 344 restart_timer: 345 batadv_v_elp_start_timer(hard_iface); 346 out: 347 return; 348 } 349 350 /** 351 * batadv_v_elp_iface_enable() - setup the ELP interface private resources 352 * @hard_iface: interface for which the data has to be prepared 353 * 354 * Return: 0 on success or a -ENOMEM in case of failure. 355 */ 356 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface) 357 { 358 static const size_t tvlv_padding = sizeof(__be32); 359 struct batadv_elp_packet *elp_packet; 360 unsigned char *elp_buff; 361 u32 random_seqno; 362 size_t size; 363 int res = -ENOMEM; 364 365 size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding; 366 hard_iface->bat_v.elp_skb = dev_alloc_skb(size); 367 if (!hard_iface->bat_v.elp_skb) 368 goto out; 369 370 skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN); 371 elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb, 372 BATADV_ELP_HLEN + tvlv_padding); 373 elp_packet = (struct batadv_elp_packet *)elp_buff; 374 375 elp_packet->packet_type = BATADV_ELP; 376 elp_packet->version = BATADV_COMPAT_VERSION; 377 378 /* randomize initial seqno to avoid collision */ 379 get_random_bytes(&random_seqno, sizeof(random_seqno)); 380 atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno); 381 382 /* assume full-duplex by default */ 383 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX; 384 385 /* warn the user (again) if there is no throughput data is available */ 386 hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT; 387 388 if (batadv_is_wifi_hardif(hard_iface)) 389 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX; 390 391 INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq, 392 batadv_v_elp_periodic_work); 393 batadv_v_elp_start_timer(hard_iface); 394 res = 0; 395 396 out: 397 return res; 398 } 399 400 /** 401 * batadv_v_elp_iface_disable() - release ELP interface private resources 402 * @hard_iface: interface for which the resources have to be released 403 */ 404 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface) 405 { 406 cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq); 407 408 dev_kfree_skb(hard_iface->bat_v.elp_skb); 409 hard_iface->bat_v.elp_skb = NULL; 410 } 411 412 /** 413 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given 414 * hard-interface 415 * @primary_iface: the new primary interface 416 * @hard_iface: interface holding the to-be-updated buffer 417 */ 418 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface, 419 struct batadv_hard_iface *hard_iface) 420 { 421 struct batadv_elp_packet *elp_packet; 422 struct sk_buff *skb; 423 424 if (!hard_iface->bat_v.elp_skb) 425 return; 426 427 skb = hard_iface->bat_v.elp_skb; 428 elp_packet = (struct batadv_elp_packet *)skb->data; 429 ether_addr_copy(elp_packet->orig, 430 primary_iface->net_dev->dev_addr); 431 } 432 433 /** 434 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new 435 * primary interface 436 * @primary_iface: the new primary interface 437 */ 438 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface) 439 { 440 struct batadv_hard_iface *hard_iface; 441 442 /* update orig field of every elp iface belonging to this mesh */ 443 rcu_read_lock(); 444 list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) { 445 if (primary_iface->soft_iface != hard_iface->soft_iface) 446 continue; 447 448 batadv_v_elp_iface_activate(primary_iface, hard_iface); 449 } 450 rcu_read_unlock(); 451 } 452 453 /** 454 * batadv_v_elp_neigh_update() - update an ELP neighbour node 455 * @bat_priv: the bat priv with all the soft interface information 456 * @neigh_addr: the neighbour interface address 457 * @if_incoming: the interface the packet was received through 458 * @elp_packet: the received ELP packet 459 * 460 * Updates the ELP neighbour node state with the data received within the new 461 * ELP packet. 462 */ 463 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv, 464 u8 *neigh_addr, 465 struct batadv_hard_iface *if_incoming, 466 struct batadv_elp_packet *elp_packet) 467 468 { 469 struct batadv_neigh_node *neigh; 470 struct batadv_orig_node *orig_neigh; 471 struct batadv_hardif_neigh_node *hardif_neigh; 472 s32 seqno_diff; 473 s32 elp_latest_seqno; 474 475 orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig); 476 if (!orig_neigh) 477 return; 478 479 neigh = batadv_neigh_node_get_or_create(orig_neigh, 480 if_incoming, neigh_addr); 481 if (!neigh) 482 goto orig_free; 483 484 hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr); 485 if (!hardif_neigh) 486 goto neigh_free; 487 488 elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno; 489 seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno; 490 491 /* known or older sequence numbers are ignored. However always adopt 492 * if the router seems to have been restarted. 493 */ 494 if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE) 495 goto hardif_free; 496 497 neigh->last_seen = jiffies; 498 hardif_neigh->last_seen = jiffies; 499 hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno); 500 hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval); 501 502 hardif_free: 503 if (hardif_neigh) 504 batadv_hardif_neigh_put(hardif_neigh); 505 neigh_free: 506 if (neigh) 507 batadv_neigh_node_put(neigh); 508 orig_free: 509 if (orig_neigh) 510 batadv_orig_node_put(orig_neigh); 511 } 512 513 /** 514 * batadv_v_elp_packet_recv() - main ELP packet handler 515 * @skb: the received packet 516 * @if_incoming: the interface this packet was received through 517 * 518 * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly 519 * processed or NET_RX_DROP in case of failure. 520 */ 521 int batadv_v_elp_packet_recv(struct sk_buff *skb, 522 struct batadv_hard_iface *if_incoming) 523 { 524 struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface); 525 struct batadv_elp_packet *elp_packet; 526 struct batadv_hard_iface *primary_if; 527 struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb); 528 bool res; 529 int ret = NET_RX_DROP; 530 531 res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN); 532 if (!res) 533 goto free_skb; 534 535 if (batadv_is_my_mac(bat_priv, ethhdr->h_source)) 536 goto free_skb; 537 538 /* did we receive a B.A.T.M.A.N. V ELP packet on an interface 539 * that does not have B.A.T.M.A.N. V ELP enabled ? 540 */ 541 if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0) 542 goto free_skb; 543 544 elp_packet = (struct batadv_elp_packet *)skb->data; 545 546 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 547 "Received ELP packet from %pM seqno %u ORIG: %pM\n", 548 ethhdr->h_source, ntohl(elp_packet->seqno), 549 elp_packet->orig); 550 551 primary_if = batadv_primary_if_get_selected(bat_priv); 552 if (!primary_if) 553 goto free_skb; 554 555 batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming, 556 elp_packet); 557 558 ret = NET_RX_SUCCESS; 559 batadv_hardif_put(primary_if); 560 561 free_skb: 562 if (ret == NET_RX_SUCCESS) 563 consume_skb(skb); 564 else 565 kfree_skb(skb); 566 567 return ret; 568 } 569