kernel-ark/net/mac80211/mesh_pathtbl.c
Johannes Berg 64592c8fc0 mac80211: use common work struct
IBSS, managed and mesh modes all have their
own work struct, and in the future we want
to also use it in other modes to process
frames from the now common skb queue.

This also makes the skb queue and work safe
to use from other interface types.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-14 15:38:17 -04:00

744 lines
19 KiB
C

/*
* Copyright (c) 2008, 2009 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/slab.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;
static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
int mesh_paths_generation;
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;
}
/* 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)
{
struct sk_buff *skb;
struct ieee80211_hdr *hdr;
struct sk_buff_head tmpq;
unsigned long flags;
rcu_assign_pointer(mpath->next_hop, sta);
__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);
}
/**
* mesh_path_lookup - look up a path in the mesh path table
* @dst: hardware address (ETH_ALEN length) of destination
* @sdata: local subif
*
* Returns: pointer to the mesh path structure, or NULL if not found
*
* Locking: must be called within a read rcu section.
*/
struct mesh_path *mesh_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(mesh_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;
}
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;
}
/**
* mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
* @idx: index
* @sdata: local subif, or NULL for all entries
*
* Returns: pointer to the mesh path structure, or NULL if not found.
*
* Locking: must be called within a read rcu section.
*/
struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
{
struct mpath_node *node;
struct hlist_node *p;
int i;
int j = 0;
for_each_mesh_entry(mesh_paths, p, node, i) {
if (sdata && node->mpath->sdata != sdata)
continue;
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;
}
}
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)
* @sdata: local subif
*
* Returns: 0 on success
*
* State: the initial state of the new path is set to 0
*/
int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct ieee80211_local *local = sdata->local;
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->vif.addr, ETH_ALEN) == 0)
/* never add ourselves as neighbours */
return -ENOTSUPP;
if (is_multicast_ether_addr(dst))
return -ENOTSUPP;
if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
return -ENOSPC;
err = -ENOMEM;
new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
if (!new_mpath)
goto err_path_alloc;
new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
if (!new_node)
goto err_node_alloc;
read_lock(&pathtbl_resize_lock);
memcpy(new_mpath->dst, dst, 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->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);
hash_idx = mesh_table_hash(dst, sdata, mesh_paths);
bucket = &mesh_paths->hash_buckets[hash_idx];
spin_lock(&mesh_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(&mesh_paths->entries) >=
mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
grow = 1;
mesh_paths_generation++;
spin_unlock(&mesh_paths->hashwlock[hash_idx]);
read_unlock(&pathtbl_resize_lock);
if (grow) {
set_bit(MESH_WORK_GROW_MPATH_TABLE, &ifmsh->wrkq_flags);
ieee80211_queue_work(&local->hw, &sdata->work);
}
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:
atomic_dec(&sdata->u.mesh.mpaths);
return err;
}
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);
}
int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct ieee80211_local *local = sdata->local;
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->vif.addr, ETH_ALEN) == 0)
/* never add ourselves as neighbours */
return -ENOTSUPP;
if (is_multicast_ether_addr(dst))
return -ENOTSUPP;
err = -ENOMEM;
new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
if (!new_mpath)
goto err_path_alloc;
new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
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) {
set_bit(MESH_WORK_GROW_MPP_TABLE, &ifmsh->wrkq_flags);
ieee80211_queue_work(&local->hw, &sdata->work);
}
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;
}
/**
* 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)
{
static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
struct mesh_path *mpath;
struct mpath_node *node;
struct hlist_node *p;
struct ieee80211_sub_if_data *sdata = sta->sdata;
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->sn;
spin_unlock_bh(&mpath->state_lock);
mesh_path_error_tx(MESH_TTL, mpath->dst,
cpu_to_le32(mpath->sn),
cpu_to_le16(PERR_RCODE_DEST_UNREACH),
bcast, sdata);
} 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
*
* 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
* sta_info_destroy() calls this) so any reader in a rcu read block will be
* protected against the plink disappearing.
*/
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)
mesh_path_del(mpath->dst, mpath->sdata);
}
}
void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
{
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->sdata == sdata)
mesh_path_del(mpath->dst, mpath->sdata);
}
}
static void mesh_path_node_reclaim(struct rcu_head *rp)
{
struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
del_timer_sync(&node->mpath->timer);
atomic_dec(&sdata->u.mesh.mpaths);
kfree(node->mpath);
kfree(node);
}
/**
* mesh_path_del - delete a mesh path from the table
*
* @addr: dst address (ETH_ALEN length)
* @sdata: local subif
*
* Returns: 0 if successful
*/
int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
{
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);
hash_idx = mesh_table_hash(addr, sdata, mesh_paths);
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;
if (mpath->sdata == sdata &&
memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
spin_lock_bh(&mpath->state_lock);
mpath->flags |= MESH_PATH_RESOLVING;
hlist_del_rcu(&node->list);
call_rcu(&node->rcu, mesh_path_node_reclaim);
atomic_dec(&mesh_paths->entries);
spin_unlock_bh(&mpath->state_lock);
goto enddel;
}
}
err = -ENXIO;
enddel:
mesh_paths_generation++;
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)
{
if (mpath->flags & MESH_PATH_ACTIVE)
ieee80211_add_pending_skbs(mpath->sdata->local,
&mpath->frame_queue);
}
/**
* mesh_path_discard_frame - discard a frame whose path could not be resolved
*
* @skb: frame to discard
* @sdata: network subif the frame was to be sent through
*
* 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.
*
* Locking: the function must me called within a rcu_read_lock region
*/
void mesh_path_discard_frame(struct sk_buff *skb,
struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct mesh_path *mpath;
u32 sn = 0;
if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
u8 *ra, *da;
da = hdr->addr3;
ra = hdr->addr1;
mpath = mesh_path_lookup(da, sdata);
if (mpath)
sn = ++mpath->sn;
mesh_path_error_tx(MESH_TTL, skb->data, cpu_to_le32(sn),
cpu_to_le16(PERR_RCODE_NO_ROUTE), ra, sdata);
}
kfree_skb(skb);
sdata->u.mesh.mshstats.dropped_frames_no_route++;
}
/**
* 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))
mesh_path_discard_frame(skb, mpath->sdata);
}
/**
* 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->sn = 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);
}
static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
{
struct mesh_path *mpath;
struct mpath_node *node, *new_node;
u32 hash_idx;
new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
if (new_node == NULL)
return -ENOMEM;
node = hlist_entry(p, struct mpath_node, list);
mpath = node->mpath;
new_node->mpath = mpath;
hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
hlist_add_head(&new_node->list,
&newtbl->hash_buckets[hash_idx]);
return 0;
}
int mesh_pathtbl_init(void)
{
mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
if (!mesh_paths)
return -ENOMEM;
mesh_paths->free_node = &mesh_path_node_free;
mesh_paths->copy_node = &mesh_path_node_copy;
mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
if (!mpp_paths) {
mesh_table_free(mesh_paths, true);
return -ENOMEM;
}
mpp_paths->free_node = &mesh_path_node_free;
mpp_paths->copy_node = &mesh_path_node_copy;
mpp_paths->mean_chain_len = MEAN_CHAIN_LEN;
return 0;
}
void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
{
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) {
if (node->mpath->sdata != sdata)
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);
mesh_path_del(mpath->dst, mpath->sdata);
} else
spin_unlock_bh(&mpath->state_lock);
}
read_unlock(&pathtbl_resize_lock);
}
void mesh_pathtbl_unregister(void)
{
mesh_table_free(mesh_paths, true);
mesh_table_free(mpp_paths, true);
}