mesh_pathtbl.c 18.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
/*
 * Copyright (c) 2008 open80211s Ltd.
 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "mesh.h"

/* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
#define INIT_PATHS_SIZE_ORDER	2

/* Keep the mean chain length below this constant */
#define MEAN_CHAIN_LEN		2

#define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
				time_after(jiffies, mpath->exp_time) && \
				!(mpath->flags & MESH_PATH_FIXED))

struct mpath_node {
	struct hlist_node list;
	struct rcu_head rcu;
	/* This indirection allows two different tables to point to the same
	 * mesh_path structure, useful when resizing
	 */
	struct mesh_path *mpath;
};

static struct mesh_table *mesh_paths;
39
static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
40

41
int mesh_paths_generation;
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
static void __mesh_table_free(struct mesh_table *tbl)
{
	kfree(tbl->hash_buckets);
	kfree(tbl->hashwlock);
	kfree(tbl);
}

void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
{
	struct hlist_head *mesh_hash;
	struct hlist_node *p, *q;
	int i;

	mesh_hash = tbl->hash_buckets;
	for (i = 0; i <= tbl->hash_mask; i++) {
		spin_lock(&tbl->hashwlock[i]);
		hlist_for_each_safe(p, q, &mesh_hash[i]) {
			tbl->free_node(p, free_leafs);
			atomic_dec(&tbl->entries);
		}
		spin_unlock(&tbl->hashwlock[i]);
	}
	__mesh_table_free(tbl);
}

static struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
{
	struct mesh_table *newtbl;
	struct hlist_head *oldhash;
	struct hlist_node *p, *q;
	int i;

	if (atomic_read(&tbl->entries)
			< tbl->mean_chain_len * (tbl->hash_mask + 1))
		goto endgrow;

	newtbl = mesh_table_alloc(tbl->size_order + 1);
	if (!newtbl)
		goto endgrow;

	newtbl->free_node = tbl->free_node;
	newtbl->mean_chain_len = tbl->mean_chain_len;
	newtbl->copy_node = tbl->copy_node;
	atomic_set(&newtbl->entries, atomic_read(&tbl->entries));

	oldhash = tbl->hash_buckets;
	for (i = 0; i <= tbl->hash_mask; i++)
		hlist_for_each(p, &oldhash[i])
			if (tbl->copy_node(p, newtbl) < 0)
				goto errcopy;

	return newtbl;

errcopy:
	for (i = 0; i <= newtbl->hash_mask; i++) {
		hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
			tbl->free_node(p, 0);
	}
	__mesh_table_free(newtbl);
endgrow:
	return NULL;
}

105

106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122
/* This lock will have the grow table function as writer and add / delete nodes
 * as readers. When reading the table (i.e. doing lookups) we are well protected
 * by RCU
 */
static DEFINE_RWLOCK(pathtbl_resize_lock);

/**
 *
 * mesh_path_assign_nexthop - update mesh path next hop
 *
 * @mpath: mesh path to update
 * @sta: next hop to assign
 *
 * Locking: mpath->state_lock must be held when calling this function
 */
void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
{
123 124 125 126 127
	struct sk_buff *skb;
	struct ieee80211_hdr *hdr;
	struct sk_buff_head tmpq;
	unsigned long flags;

128
	rcu_assign_pointer(mpath->next_hop, sta);
129 130 131 132 133 134 135 136 137 138 139 140 141

	__skb_queue_head_init(&tmpq);

	spin_lock_irqsave(&mpath->frame_queue.lock, flags);

	while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
		hdr = (struct ieee80211_hdr *) skb->data;
		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
		__skb_queue_tail(&tmpq, skb);
	}

	skb_queue_splice(&tmpq, &mpath->frame_queue);
	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
142 143 144 145 146 147
}


/**
 * mesh_path_lookup - look up a path in the mesh path table
 * @dst: hardware address (ETH_ALEN length) of destination
148
 * @sdata: local subif
149 150 151 152 153
 *
 * Returns: pointer to the mesh path structure, or NULL if not found
 *
 * Locking: must be called within a read rcu section.
 */
154
struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
155 156 157 158 159 160 161 162 163
{
	struct mesh_path *mpath;
	struct hlist_node *n;
	struct hlist_head *bucket;
	struct mesh_table *tbl;
	struct mpath_node *node;

	tbl = rcu_dereference(mesh_paths);

164
	bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
165 166
	hlist_for_each_entry_rcu(node, n, bucket, list) {
		mpath = node->mpath;
167
		if (mpath->sdata == sdata &&
168 169 170 171 172 173 174 175 176 177 178 179 180
				memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
			if (MPATH_EXPIRED(mpath)) {
				spin_lock_bh(&mpath->state_lock);
				if (MPATH_EXPIRED(mpath))
					mpath->flags &= ~MESH_PATH_ACTIVE;
				spin_unlock_bh(&mpath->state_lock);
			}
			return mpath;
		}
	}
	return NULL;
}

181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
{
	struct mesh_path *mpath;
	struct hlist_node *n;
	struct hlist_head *bucket;
	struct mesh_table *tbl;
	struct mpath_node *node;

	tbl = rcu_dereference(mpp_paths);

	bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
	hlist_for_each_entry_rcu(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->sdata == sdata &&
		    memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
			if (MPATH_EXPIRED(mpath)) {
				spin_lock_bh(&mpath->state_lock);
				if (MPATH_EXPIRED(mpath))
					mpath->flags &= ~MESH_PATH_ACTIVE;
				spin_unlock_bh(&mpath->state_lock);
			}
			return mpath;
		}
	}
	return NULL;
}


209 210 211
/**
 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 * @idx: index
212
 * @sdata: local subif, or NULL for all entries
213 214 215 216 217
 *
 * Returns: pointer to the mesh path structure, or NULL if not found.
 *
 * Locking: must be called within a read rcu section.
 */
218
struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
219 220 221 222 223 224
{
	struct mpath_node *node;
	struct hlist_node *p;
	int i;
	int j = 0;

225
	for_each_mesh_entry(mesh_paths, p, node, i) {
226
		if (sdata && node->mpath->sdata != sdata)
227
			continue;
228 229 230 231 232 233 234 235 236
		if (j++ == idx) {
			if (MPATH_EXPIRED(node->mpath)) {
				spin_lock_bh(&node->mpath->state_lock);
				if (MPATH_EXPIRED(node->mpath))
					node->mpath->flags &= ~MESH_PATH_ACTIVE;
				spin_unlock_bh(&node->mpath->state_lock);
			}
			return node->mpath;
		}
237
	}
238 239 240 241 242 243 244

	return NULL;
}

/**
 * mesh_path_add - allocate and add a new path to the mesh path table
 * @addr: destination address of the path (ETH_ALEN length)
245
 * @sdata: local subif
246 247 248 249 250
 *
 * Returns: 0 on sucess
 *
 * State: the initial state of the new path is set to 0
 */
251
int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
252
{
253 254
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
	struct ieee80211_local *local = sdata->local;
255 256 257 258 259 260 261 262
	struct mesh_path *mpath, *new_mpath;
	struct mpath_node *node, *new_node;
	struct hlist_head *bucket;
	struct hlist_node *n;
	int grow = 0;
	int err = 0;
	u32 hash_idx;

263
	if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
264 265 266 267 268 269
		/* never add ourselves as neighbours */
		return -ENOTSUPP;

	if (is_multicast_ether_addr(dst))
		return -ENOTSUPP;

270
	if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
271 272
		return -ENOSPC;

273
	err = -ENOMEM;
274
	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
275 276 277
	if (!new_mpath)
		goto err_path_alloc;

278
	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
279 280
	if (!new_node)
		goto err_node_alloc;
281 282

	read_lock(&pathtbl_resize_lock);
283
	memcpy(new_mpath->dst, dst, ETH_ALEN);
284
	new_mpath->sdata = sdata;
285 286 287 288 289 290 291 292 293
	new_mpath->flags = 0;
	skb_queue_head_init(&new_mpath->frame_queue);
	new_node->mpath = new_mpath;
	new_mpath->timer.data = (unsigned long) new_mpath;
	new_mpath->timer.function = mesh_path_timer;
	new_mpath->exp_time = jiffies;
	spin_lock_init(&new_mpath->state_lock);
	init_timer(&new_mpath->timer);

294
	hash_idx = mesh_table_hash(dst, sdata, mesh_paths);
295 296 297 298
	bucket = &mesh_paths->hash_buckets[hash_idx];

	spin_lock(&mesh_paths->hashwlock[hash_idx]);

299
	err = -EEXIST;
300 301
	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
302
		if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
303
			goto err_exists;
304 305 306 307 308 309 310
	}

	hlist_add_head_rcu(&new_node->list, bucket);
	if (atomic_inc_return(&mesh_paths->entries) >=
		mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
		grow = 1;

311 312
	mesh_paths_generation++;

313 314
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
315
	if (grow) {
316 317
		set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
		ieee80211_queue_work(&local->hw, &ifmsh->work);
318
	}
319 320 321 322 323 324 325 326 327
	return 0;

err_exists:
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	kfree(new_node);
err_node_alloc:
	kfree(new_mpath);
err_path_alloc:
328
	atomic_dec(&sdata->u.mesh.mpaths);
329 330 331
	return err;
}

332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366
void mesh_mpath_table_grow(void)
{
	struct mesh_table *oldtbl, *newtbl;

	write_lock(&pathtbl_resize_lock);
	oldtbl = mesh_paths;
	newtbl = mesh_table_grow(mesh_paths);
	if (!newtbl) {
		write_unlock(&pathtbl_resize_lock);
		return;
	}
	rcu_assign_pointer(mesh_paths, newtbl);
	write_unlock(&pathtbl_resize_lock);

	synchronize_rcu();
	mesh_table_free(oldtbl, false);
}

void mesh_mpp_table_grow(void)
{
	struct mesh_table *oldtbl, *newtbl;

	write_lock(&pathtbl_resize_lock);
	oldtbl = mpp_paths;
	newtbl = mesh_table_grow(mpp_paths);
	if (!newtbl) {
		write_unlock(&pathtbl_resize_lock);
		return;
	}
	rcu_assign_pointer(mpp_paths, newtbl);
	write_unlock(&pathtbl_resize_lock);

	synchronize_rcu();
	mesh_table_free(oldtbl, false);
}
367

368 369
int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
{
370 371
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
	struct ieee80211_local *local = sdata->local;
372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387
	struct mesh_path *mpath, *new_mpath;
	struct mpath_node *node, *new_node;
	struct hlist_head *bucket;
	struct hlist_node *n;
	int grow = 0;
	int err = 0;
	u32 hash_idx;

	if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
		/* never add ourselves as neighbours */
		return -ENOTSUPP;

	if (is_multicast_ether_addr(dst))
		return -ENOTSUPP;

	err = -ENOMEM;
388
	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
389 390 391
	if (!new_mpath)
		goto err_path_alloc;

392
	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
	if (!new_node)
		goto err_node_alloc;

	read_lock(&pathtbl_resize_lock);
	memcpy(new_mpath->dst, dst, ETH_ALEN);
	memcpy(new_mpath->mpp, mpp, ETH_ALEN);
	new_mpath->sdata = sdata;
	new_mpath->flags = 0;
	skb_queue_head_init(&new_mpath->frame_queue);
	new_node->mpath = new_mpath;
	new_mpath->exp_time = jiffies;
	spin_lock_init(&new_mpath->state_lock);

	hash_idx = mesh_table_hash(dst, sdata, mpp_paths);
	bucket = &mpp_paths->hash_buckets[hash_idx];

	spin_lock(&mpp_paths->hashwlock[hash_idx]);

	err = -EEXIST;
	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
			goto err_exists;
	}

	hlist_add_head_rcu(&new_node->list, bucket);
	if (atomic_inc_return(&mpp_paths->entries) >=
		mpp_paths->mean_chain_len * (mpp_paths->hash_mask + 1))
		grow = 1;

	spin_unlock(&mpp_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	if (grow) {
426 427
		set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
		ieee80211_queue_work(&local->hw, &ifmsh->work);
428 429 430 431 432 433 434 435 436 437 438 439 440 441
	}
	return 0;

err_exists:
	spin_unlock(&mpp_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	kfree(new_node);
err_node_alloc:
	kfree(new_mpath);
err_path_alloc:
	return err;
}


442 443 444 445 446 447 448 449 450 451 452 453 454
/**
 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 *
 * @sta: broken peer link
 *
 * This function must be called from the rate control algorithm if enough
 * delivery errors suggest that a peer link is no longer usable.
 */
void mesh_plink_broken(struct sta_info *sta)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
455
	struct ieee80211_sub_if_data *sdata = sta->sdata;
456 457 458 459 460 461 462 463 464 465 466 467 468 469
	int i;

	rcu_read_lock();
	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
		spin_lock_bh(&mpath->state_lock);
		if (mpath->next_hop == sta &&
		    mpath->flags & MESH_PATH_ACTIVE &&
		    !(mpath->flags & MESH_PATH_FIXED)) {
			mpath->flags &= ~MESH_PATH_ACTIVE;
			++mpath->dsn;
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_error_tx(mpath->dst,
					cpu_to_le32(mpath->dsn),
470
					sdata->dev->broadcast, sdata);
471 472 473 474 475 476 477 478 479 480 481
		} else
		spin_unlock_bh(&mpath->state_lock);
	}
	rcu_read_unlock();
}

/**
 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 *
 * @sta - mesh peer to match
 *
482 483 484
 * RCU notes: this function is called when a mesh plink transitions from
 * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 * allows path creation. This will happen before the sta can be freed (because
485 486
 * sta_info_destroy() calls this) so any reader in a rcu read block will be
 * protected against the plink disappearing.
487 488 489 490 491 492 493 494 495 496 497
 */
void mesh_path_flush_by_nexthop(struct sta_info *sta)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
		if (mpath->next_hop == sta)
498
			mesh_path_del(mpath->dst, mpath->sdata);
499 500 501
	}
}

502
void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
503 504 505 506 507 508 509 510
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
511 512
		if (mpath->sdata == sdata)
			mesh_path_del(mpath->dst, mpath->sdata);
513 514 515 516 517 518
	}
}

static void mesh_path_node_reclaim(struct rcu_head *rp)
{
	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
519
	struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
520

521
	del_timer_sync(&node->mpath->timer);
522
	atomic_dec(&sdata->u.mesh.mpaths);
523 524 525 526 527 528 529 530
	kfree(node->mpath);
	kfree(node);
}

/**
 * mesh_path_del - delete a mesh path from the table
 *
 * @addr: dst address (ETH_ALEN length)
531
 * @sdata: local subif
532 533 534
 *
 * Returns: 0 if succesful
 */
535
int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
536 537 538 539 540 541 542 543 544
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_head *bucket;
	struct hlist_node *n;
	int hash_idx;
	int err = 0;

	read_lock(&pathtbl_resize_lock);
545
	hash_idx = mesh_table_hash(addr, sdata, mesh_paths);
546 547 548 549 550
	bucket = &mesh_paths->hash_buckets[hash_idx];

	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
551
		if (mpath->sdata == sdata &&
552 553
				memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
			spin_lock_bh(&mpath->state_lock);
554 555 556 557
			mpath->flags |= MESH_PATH_RESOLVING;
			hlist_del_rcu(&node->list);
			call_rcu(&node->rcu, mesh_path_node_reclaim);
			atomic_dec(&mesh_paths->entries);
558 559 560 561 562 563 564
			spin_unlock_bh(&mpath->state_lock);
			goto enddel;
		}
	}

	err = -ENXIO;
enddel:
565
	mesh_paths_generation++;
566 567 568 569 570 571 572 573 574 575 576 577 578 579 580
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	return err;
}

/**
 * mesh_path_tx_pending - sends pending frames in a mesh path queue
 *
 * @mpath: mesh path to activate
 *
 * Locking: the state_lock of the mpath structure must NOT be held when calling
 * this function.
 */
void mesh_path_tx_pending(struct mesh_path *mpath)
{
581 582 583
	if (mpath->flags & MESH_PATH_ACTIVE)
		ieee80211_add_pending_skbs(mpath->sdata->local,
				&mpath->frame_queue);
584 585 586 587 588 589
}

/**
 * mesh_path_discard_frame - discard a frame whose path could not be resolved
 *
 * @skb: frame to discard
590
 * @sdata: network subif the frame was to be sent through
591
 *
592 593 594 595
 * If the frame was being forwarded from another MP, a PERR frame will be sent
 * to the precursor.  The precursor's address (i.e. the previous hop) was saved
 * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
 * the destination is successfully resolved.
596 597 598
 *
 * Locking: the function must me called within a rcu_read_lock region
 */
599 600
void mesh_path_discard_frame(struct sk_buff *skb,
			     struct ieee80211_sub_if_data *sdata)
601
{
602
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
603 604 605
	struct mesh_path *mpath;
	u32 dsn = 0;

606
	if (memcmp(hdr->addr4, sdata->dev->dev_addr, ETH_ALEN) != 0) {
607 608
		u8 *ra, *da;

609
		da = hdr->addr3;
610
		ra = hdr->addr1;
611
		mpath = mesh_path_lookup(da, sdata);
612 613
		if (mpath)
			dsn = ++mpath->dsn;
614
		mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, sdata);
615 616 617
	}

	kfree_skb(skb);
618
	sdata->u.mesh.mshstats.dropped_frames_no_route++;
619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
}

/**
 * mesh_path_flush_pending - free the pending queue of a mesh path
 *
 * @mpath: mesh path whose queue has to be freed
 *
 * Locking: the function must me called withing a rcu_read_lock region
 */
void mesh_path_flush_pending(struct mesh_path *mpath)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
			(mpath->flags & MESH_PATH_ACTIVE))
634
		mesh_path_discard_frame(skb, mpath->sdata);
635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669
}

/**
 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 *
 * @mpath: the mesh path to modify
 * @next_hop: the next hop to force
 *
 * Locking: this function must be called holding mpath->state_lock
 */
void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
{
	spin_lock_bh(&mpath->state_lock);
	mesh_path_assign_nexthop(mpath, next_hop);
	mpath->dsn = 0xffff;
	mpath->metric = 0;
	mpath->hop_count = 0;
	mpath->exp_time = 0;
	mpath->flags |= MESH_PATH_FIXED;
	mesh_path_activate(mpath);
	spin_unlock_bh(&mpath->state_lock);
	mesh_path_tx_pending(mpath);
}

static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
{
	struct mesh_path *mpath;
	struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
	mpath = node->mpath;
	hlist_del_rcu(p);
	if (free_leafs)
		kfree(mpath);
	kfree(node);
}

670
static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
671 672 673 674 675
{
	struct mesh_path *mpath;
	struct mpath_node *node, *new_node;
	u32 hash_idx;

676
	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
677 678 679
	if (new_node == NULL)
		return -ENOMEM;

680 681 682
	node = hlist_entry(p, struct mpath_node, list);
	mpath = node->mpath;
	new_node->mpath = mpath;
683
	hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
684 685
	hlist_add_head(&new_node->list,
			&newtbl->hash_buckets[hash_idx]);
686
	return 0;
687 688 689 690 691
}

int mesh_pathtbl_init(void)
{
	mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
692 693
	if (!mesh_paths)
		return -ENOMEM;
694 695 696
	mesh_paths->free_node = &mesh_path_node_free;
	mesh_paths->copy_node = &mesh_path_node_copy;
	mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
697 698 699 700

	mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
	if (!mpp_paths) {
		mesh_table_free(mesh_paths, true);
701
		return -ENOMEM;
702 703 704 705 706
	}
	mpp_paths->free_node = &mesh_path_node_free;
	mpp_paths->copy_node = &mesh_path_node_copy;
	mpp_paths->mean_chain_len = MEAN_CHAIN_LEN;

707 708 709
	return 0;
}

710
void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
711 712 713 714 715 716 717 718
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	read_lock(&pathtbl_resize_lock);
	for_each_mesh_entry(mesh_paths, p, node, i) {
719
		if (node->mpath->sdata != sdata)
720 721 722 723 724 725 726 727
			continue;
		mpath = node->mpath;
		spin_lock_bh(&mpath->state_lock);
		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
		    (!(mpath->flags & MESH_PATH_FIXED)) &&
			time_after(jiffies,
			 mpath->exp_time + MESH_PATH_EXPIRE)) {
			spin_unlock_bh(&mpath->state_lock);
728
			mesh_path_del(mpath->dst, mpath->sdata);
729 730 731 732 733 734 735 736 737
		} else
			spin_unlock_bh(&mpath->state_lock);
	}
	read_unlock(&pathtbl_resize_lock);
}

void mesh_pathtbl_unregister(void)
{
	mesh_table_free(mesh_paths, true);
738
	mesh_table_free(mpp_paths, true);
739
}