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linux/net/mac80211/mesh_hwmp.c

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/*
* 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 "mesh.h"
#define TEST_FRAME_LEN 8192
#define MAX_METRIC 0xffffffff
#define ARITH_SHIFT 8
/* Number of frames buffered per destination for unresolved destinations */
#define MESH_FRAME_QUEUE_LEN 10
#define MAX_PREQ_QUEUE_LEN 64
/* Destination only */
#define MP_F_DO 0x1
/* Reply and forward */
#define MP_F_RF 0x2
static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
{
if (ae)
offset += 6;
return get_unaligned_le32(preq_elem + offset);
}
/* HWMP IE processing macros */
#define AE_F (1<<6)
#define AE_F_SET(x) (*x & AE_F)
#define PREQ_IE_FLAGS(x) (*(x))
#define PREQ_IE_HOPCOUNT(x) (*(x + 1))
#define PREQ_IE_TTL(x) (*(x + 2))
#define PREQ_IE_PREQ_ID(x) u32_field_get(x, 3, 0)
#define PREQ_IE_ORIG_ADDR(x) (x + 7)
#define PREQ_IE_ORIG_DSN(x) u32_field_get(x, 13, 0);
#define PREQ_IE_LIFETIME(x) u32_field_get(x, 17, AE_F_SET(x));
#define PREQ_IE_METRIC(x) u32_field_get(x, 21, AE_F_SET(x));
#define PREQ_IE_DST_F(x) (*(AE_F_SET(x) ? x + 32 : x + 26))
#define PREQ_IE_DST_ADDR(x) (AE_F_SET(x) ? x + 33 : x + 27)
#define PREQ_IE_DST_DSN(x) u32_field_get(x, 33, AE_F_SET(x));
#define PREP_IE_FLAGS(x) PREQ_IE_FLAGS(x)
#define PREP_IE_HOPCOUNT(x) PREQ_IE_HOPCOUNT(x)
#define PREP_IE_TTL(x) PREQ_IE_TTL(x)
#define PREP_IE_ORIG_ADDR(x) (x + 3)
#define PREP_IE_ORIG_DSN(x) u32_field_get(x, 9, 0);
#define PREP_IE_LIFETIME(x) u32_field_get(x, 13, AE_F_SET(x));
#define PREP_IE_METRIC(x) u32_field_get(x, 17, AE_F_SET(x));
#define PREP_IE_DST_ADDR(x) (AE_F_SET(x) ? x + 27 : x + 21)
#define PREP_IE_DST_DSN(x) u32_field_get(x, 27, AE_F_SET(x));
#define PERR_IE_DST_ADDR(x) (x + 2)
#define PERR_IE_DST_DSN(x) u32_field_get(x, 8, 0);
#define TU_TO_EXP_TIME(x) (jiffies + msecs_to_jiffies(x * 1024 / 1000))
#define MSEC_TO_TU(x) (x*1000/1024)
#define DSN_GT(x, y) ((long) (y) - (long) (x) < 0)
#define DSN_LT(x, y) ((long) (x) - (long) (y) < 0)
#define net_traversal_jiffies(s) \
msecs_to_jiffies(s->u.sta.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
#define default_lifetime(s) \
MSEC_TO_TU(s->u.sta.mshcfg.dot11MeshHWMPactivePathTimeout)
#define min_preq_int_jiff(s) \
(msecs_to_jiffies(s->u.sta.mshcfg.dot11MeshHWMPpreqMinInterval))
#define max_preq_retries(s) (s->u.sta.mshcfg.dot11MeshHWMPmaxPREQretries)
#define disc_timeout_jiff(s) \
msecs_to_jiffies(sdata->u.sta.mshcfg.min_discovery_timeout)
enum mpath_frame_type {
MPATH_PREQ = 0,
MPATH_PREP,
MPATH_PERR
};
static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
u8 *orig_addr, __le32 orig_dsn, u8 dst_flags, u8 *dst,
__le32 dst_dsn, u8 *da, u8 hop_count, u8 ttl, __le32 lifetime,
__le32 metric, __le32 preq_id, struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
struct ieee80211_mgmt *mgmt;
u8 *pos;
int ie_len;
if (!skb)
return -1;
skb_reserve(skb, local->hw.extra_tx_headroom);
/* 25 is the size of the common mgmt part (24) plus the size of the
* common action part (1)
*/
mgmt = (struct ieee80211_mgmt *)
skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
IEEE80211_STYPE_ACTION);
memcpy(mgmt->da, da, ETH_ALEN);
memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
/* BSSID is left zeroed, wildcard value */
mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
mgmt->u.action.u.mesh_action.action_code = action;
switch (action) {
case MPATH_PREQ:
ie_len = 37;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PREQ;
break;
case MPATH_PREP:
ie_len = 31;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PREP;
break;
default:
kfree_skb(skb);
return -ENOTSUPP;
break;
}
*pos++ = ie_len;
*pos++ = flags;
*pos++ = hop_count;
*pos++ = ttl;
if (action == MPATH_PREQ) {
memcpy(pos, &preq_id, 4);
pos += 4;
}
memcpy(pos, orig_addr, ETH_ALEN);
pos += ETH_ALEN;
memcpy(pos, &orig_dsn, 4);
pos += 4;
memcpy(pos, &lifetime, 4);
pos += 4;
memcpy(pos, &metric, 4);
pos += 4;
if (action == MPATH_PREQ) {
/* destination count */
*pos++ = 1;
*pos++ = dst_flags;
}
memcpy(pos, dst, ETH_ALEN);
pos += ETH_ALEN;
memcpy(pos, &dst_dsn, 4);
ieee80211_sta_tx(dev, skb, 0);
return 0;
}
/**
* mesh_send_path error - Sends a PERR mesh management frame
*
* @dst: broken destination
* @dst_dsn: dsn of the broken destination
* @ra: node this frame is addressed to
*/
int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
struct ieee80211_mgmt *mgmt;
u8 *pos;
int ie_len;
if (!skb)
return -1;
skb_reserve(skb, local->hw.extra_tx_headroom);
/* 25 is the size of the common mgmt part (24) plus the size of the
* common action part (1)
*/
mgmt = (struct ieee80211_mgmt *)
skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
IEEE80211_STYPE_ACTION);
memcpy(mgmt->da, ra, ETH_ALEN);
memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
/* BSSID is left zeroed, wildcard value */
mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
mgmt->u.action.u.mesh_action.action_code = MPATH_PERR;
ie_len = 12;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PERR;
*pos++ = ie_len;
/* mode flags, reserved */
*pos++ = 0;
/* number of destinations */
*pos++ = 1;
memcpy(pos, dst, ETH_ALEN);
pos += ETH_ALEN;
memcpy(pos, &dst_dsn, 4);
ieee80211_sta_tx(dev, skb, 0);
return 0;
}
static u32 airtime_link_metric_get(struct ieee80211_local *local,
struct sta_info *sta)
{
struct ieee80211_supported_band *sband;
/* This should be adjusted for each device */
int device_constant = 1 << ARITH_SHIFT;
int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
int s_unit = 1 << ARITH_SHIFT;
int rate, err;
u32 tx_time, estimated_retx;
u64 result;
sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
if (sta->fail_avg >= 100)
return MAX_METRIC;
err = (sta->fail_avg << ARITH_SHIFT) / 100;
/* bitrate is in units of 100 Kbps, while we need rate in units of
* 1Mbps. This will be corrected on tx_time computation.
*/
rate = sband->bitrates[sta->txrate_idx].bitrate;
tx_time = (device_constant + 10 * test_frame_len / rate);
estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
return (u32)result;
}
/**
* hwmp_route_info_get - Update routing info to originator and transmitter
*
* @dev: local mesh interface
* @mgmt: mesh management frame
* @hwmp_ie: hwmp information element (PREP or PREQ)
*
* This function updates the path routing information to the originator and the
* transmitter of a HWMP PREQ or PREP fram.
*
* Returns: metric to frame originator or 0 if the frame should not be further
* processed
*
* Notes: this function is the only place (besides user-provided info) where
* path routing information is updated.
*/
static u32 hwmp_route_info_get(struct net_device *dev,
struct ieee80211_mgmt *mgmt,
u8 *hwmp_ie)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct mesh_path *mpath;
struct sta_info *sta;
bool fresh_info;
u8 *orig_addr, *ta;
u32 orig_dsn, orig_metric;
unsigned long orig_lifetime, exp_time;
u32 last_hop_metric, new_metric;
bool process = true;
u8 action = mgmt->u.action.u.mesh_action.action_code;
rcu_read_lock();
sta = sta_info_get(local, mgmt->sa);
if (!sta) {
rcu_read_unlock();
return 0;
}
last_hop_metric = airtime_link_metric_get(local, sta);
/* Update and check originator routing info */
fresh_info = true;
switch (action) {
case MPATH_PREQ:
orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
orig_metric = PREQ_IE_METRIC(hwmp_ie);
break;
case MPATH_PREP:
/* Originator here refers to the MP that was the destination in
* the Path Request. The draft refers to that MP as the
* destination address, even though usually it is the origin of
* the PREP frame. We divert from the nomenclature in the draft
* so that we can easily use a single function to gather path
* information from both PREQ and PREP frames.
*/
orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
orig_metric = PREP_IE_METRIC(hwmp_ie);
break;
default:
rcu_read_unlock();
return 0;
}
new_metric = orig_metric + last_hop_metric;
if (new_metric < orig_metric)
new_metric = MAX_METRIC;
exp_time = TU_TO_EXP_TIME(orig_lifetime);
if (memcmp(orig_addr, dev->dev_addr, ETH_ALEN) == 0) {
/* This MP is the originator, we are not interested in this
* frame, except for updating transmitter's path info.
*/
process = false;
fresh_info = false;
} else {
mpath = mesh_path_lookup(orig_addr, dev);
if (mpath) {
spin_lock_bh(&mpath->state_lock);
if (mpath->flags & MESH_PATH_FIXED)
fresh_info = false;
else if ((mpath->flags & MESH_PATH_ACTIVE) &&
(mpath->flags & MESH_PATH_DSN_VALID)) {
if (DSN_GT(mpath->dsn, orig_dsn) ||
(mpath->dsn == orig_dsn &&
action == MPATH_PREQ &&
new_metric > mpath->metric)) {
process = false;
fresh_info = false;
}
}
} else {
mesh_path_add(orig_addr, dev);
mpath = mesh_path_lookup(orig_addr, dev);
if (!mpath) {
rcu_read_unlock();
return 0;
}
spin_lock_bh(&mpath->state_lock);
}
if (fresh_info) {
mesh_path_assign_nexthop(mpath, sta);
mpath->flags |= MESH_PATH_DSN_VALID;
mpath->metric = new_metric;
mpath->dsn = orig_dsn;
mpath->exp_time = time_after(mpath->exp_time, exp_time)
? mpath->exp_time : exp_time;
mesh_path_activate(mpath);
spin_unlock_bh(&mpath->state_lock);
mesh_path_tx_pending(mpath);
/* draft says preq_id should be saved to, but there does
* not seem to be any use for it, skipping by now
*/
} else
spin_unlock_bh(&mpath->state_lock);
}
/* Update and check transmitter routing info */
ta = mgmt->sa;
if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
fresh_info = false;
else {
fresh_info = true;
mpath = mesh_path_lookup(ta, dev);
if (mpath) {
spin_lock_bh(&mpath->state_lock);
if ((mpath->flags & MESH_PATH_FIXED) ||
((mpath->flags & MESH_PATH_ACTIVE) &&
(last_hop_metric > mpath->metric)))
fresh_info = false;
} else {
mesh_path_add(ta, dev);
mpath = mesh_path_lookup(ta, dev);
if (!mpath) {
rcu_read_unlock();
return 0;
}
spin_lock_bh(&mpath->state_lock);
}
if (fresh_info) {
mesh_path_assign_nexthop(mpath, sta);
mpath->flags &= ~MESH_PATH_DSN_VALID;
mpath->metric = last_hop_metric;
mpath->exp_time = time_after(mpath->exp_time, exp_time)
? mpath->exp_time : exp_time;
mesh_path_activate(mpath);
spin_unlock_bh(&mpath->state_lock);
mesh_path_tx_pending(mpath);
} else
spin_unlock_bh(&mpath->state_lock);
}
rcu_read_unlock();
return process ? new_metric : 0;
}
static void hwmp_preq_frame_process(struct net_device *dev,
struct ieee80211_mgmt *mgmt,
u8 *preq_elem, u32 metric) {
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_if_sta *ifsta = &sdata->u.sta;
struct mesh_path *mpath;
u8 *dst_addr, *orig_addr;
u8 dst_flags, ttl;
u32 orig_dsn, dst_dsn, lifetime;
bool reply = false;
bool forward = true;
/* Update destination DSN, if present */
dst_addr = PREQ_IE_DST_ADDR(preq_elem);
orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
dst_dsn = PREQ_IE_DST_DSN(preq_elem);
orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
dst_flags = PREQ_IE_DST_F(preq_elem);
if (memcmp(dst_addr, dev->dev_addr, ETH_ALEN) == 0) {
forward = false;
reply = true;
metric = 0;
if (time_after(jiffies, ifsta->last_dsn_update +
net_traversal_jiffies(sdata)) ||
time_before(jiffies, ifsta->last_dsn_update)) {
dst_dsn = ++ifsta->dsn;
ifsta->last_dsn_update = jiffies;
}
} else {
rcu_read_lock();
mpath = mesh_path_lookup(dst_addr, dev);
if (mpath) {
if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
DSN_LT(mpath->dsn, dst_dsn)) {
mpath->dsn = dst_dsn;
mpath->flags &= MESH_PATH_DSN_VALID;
} else if ((!(dst_flags & MP_F_DO)) &&
(mpath->flags & MESH_PATH_ACTIVE)) {
reply = true;
metric = mpath->metric;
dst_dsn = mpath->dsn;
if (dst_flags & MP_F_RF)
dst_flags |= MP_F_DO;
else
forward = false;
}
}
rcu_read_unlock();
}
if (reply) {
lifetime = PREQ_IE_LIFETIME(preq_elem);
ttl = ifsta->mshcfg.dot11MeshTTL;
if (ttl != 0)
mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
cpu_to_le32(dst_dsn), 0, orig_addr,
cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
cpu_to_le32(lifetime), cpu_to_le32(metric),
0, dev);
else
ifsta->mshstats.dropped_frames_ttl++;
}
if (forward) {
u32 preq_id;
u8 hopcount, flags;
ttl = PREQ_IE_TTL(preq_elem);
lifetime = PREQ_IE_LIFETIME(preq_elem);
if (ttl <= 1) {
ifsta->mshstats.dropped_frames_ttl++;
return;
}
--ttl;
flags = PREQ_IE_FLAGS(preq_elem);
preq_id = PREQ_IE_PREQ_ID(preq_elem);
hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
cpu_to_le32(orig_dsn), dst_flags, dst_addr,
cpu_to_le32(dst_dsn), dev->broadcast,
hopcount, ttl, cpu_to_le32(lifetime),
cpu_to_le32(metric), cpu_to_le32(preq_id),
dev);
ifsta->mshstats.fwded_frames++;
}
}
static void hwmp_prep_frame_process(struct net_device *dev,
struct ieee80211_mgmt *mgmt,
u8 *prep_elem, u32 metric)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct mesh_path *mpath;
u8 *dst_addr, *orig_addr;
u8 ttl, hopcount, flags;
u8 next_hop[ETH_ALEN];
u32 dst_dsn, orig_dsn, lifetime;
/* Note that we divert from the draft nomenclature and denominate
* destination to what the draft refers to as origininator. So in this
* function destnation refers to the final destination of the PREP,
* which corresponds with the originator of the PREQ which this PREP
* replies
*/
dst_addr = PREP_IE_DST_ADDR(prep_elem);
if (memcmp(dst_addr, dev->dev_addr, ETH_ALEN) == 0)
/* destination, no forwarding required */
return;
ttl = PREP_IE_TTL(prep_elem);
if (ttl <= 1) {
sdata->u.sta.mshstats.dropped_frames_ttl++;
return;
}
rcu_read_lock();
mpath = mesh_path_lookup(dst_addr, dev);
if (mpath)
spin_lock_bh(&mpath->state_lock);
else
goto fail;
if (!(mpath->flags & MESH_PATH_ACTIVE)) {
spin_unlock_bh(&mpath->state_lock);
goto fail;
}
memcpy(next_hop, mpath->next_hop->addr, ETH_ALEN);
spin_unlock_bh(&mpath->state_lock);
--ttl;
flags = PREP_IE_FLAGS(prep_elem);
lifetime = PREP_IE_LIFETIME(prep_elem);
hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
dst_dsn = PREP_IE_DST_DSN(prep_elem);
orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
cpu_to_le32(orig_dsn), 0, dst_addr,
cpu_to_le32(dst_dsn), mpath->next_hop->addr, hopcount, ttl,
cpu_to_le32(lifetime), cpu_to_le32(metric),
0, dev);
rcu_read_unlock();
sdata->u.sta.mshstats.fwded_frames++;
return;
fail:
rcu_read_unlock();
sdata->u.sta.mshstats.dropped_frames_no_route++;
return;
}
static void hwmp_perr_frame_process(struct net_device *dev,
struct ieee80211_mgmt *mgmt, u8 *perr_elem)
{
struct mesh_path *mpath;
u8 *ta, *dst_addr;
u32 dst_dsn;
ta = mgmt->sa;
dst_addr = PERR_IE_DST_ADDR(perr_elem);
dst_dsn = PERR_IE_DST_DSN(perr_elem);
rcu_read_lock();
mpath = mesh_path_lookup(dst_addr, dev);
if (mpath) {
spin_lock_bh(&mpath->state_lock);
if (mpath->flags & MESH_PATH_ACTIVE &&
memcmp(ta, mpath->next_hop->addr, ETH_ALEN) == 0 &&
(!(mpath->flags & MESH_PATH_DSN_VALID) ||
DSN_GT(dst_dsn, mpath->dsn))) {
mpath->flags &= ~MESH_PATH_ACTIVE;
mpath->dsn = dst_dsn;
spin_unlock_bh(&mpath->state_lock);
mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
dev->broadcast, dev);
} else
spin_unlock_bh(&mpath->state_lock);
}
rcu_read_unlock();
}
void mesh_rx_path_sel_frame(struct net_device *dev,
struct ieee80211_mgmt *mgmt,
size_t len)
{
struct ieee802_11_elems elems;
size_t baselen;
u32 last_hop_metric;
baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
len - baselen, &elems);
switch (mgmt->u.action.u.mesh_action.action_code) {
case MPATH_PREQ:
if (!elems.preq || elems.preq_len != 37)
/* Right now we support just 1 destination and no AE */
return;
last_hop_metric = hwmp_route_info_get(dev, mgmt, elems.preq);
if (!last_hop_metric)
return;
hwmp_preq_frame_process(dev, mgmt, elems.preq, last_hop_metric);
break;
case MPATH_PREP:
if (!elems.prep || elems.prep_len != 31)
/* Right now we support no AE */
return;
last_hop_metric = hwmp_route_info_get(dev, mgmt, elems.prep);
if (!last_hop_metric)
return;
hwmp_prep_frame_process(dev, mgmt, elems.prep, last_hop_metric);
break;
case MPATH_PERR:
if (!elems.perr || elems.perr_len != 12)
/* Right now we support only one destination per PERR */
return;
hwmp_perr_frame_process(dev, mgmt, elems.perr);
default:
return;
}
}
/**
* mesh_queue_preq - queue a PREQ to a given destination
*
* @mpath: mesh path to discover
* @flags: special attributes of the PREQ to be sent
*
* Locking: the function must be called from within a rcu read lock block.
*
*/
static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
{
struct ieee80211_sub_if_data *sdata =
IEEE80211_DEV_TO_SUB_IF(mpath->dev);
struct ieee80211_if_sta *ifsta = &sdata->u.sta;
struct mesh_preq_queue *preq_node;
preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
if (!preq_node) {
printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
return;
}
spin_lock(&ifsta->mesh_preq_queue_lock);
if (ifsta->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
spin_unlock(&ifsta->mesh_preq_queue_lock);
kfree(preq_node);
if (printk_ratelimit())
printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
return;
}
memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
preq_node->flags = flags;
list_add_tail(&preq_node->list, &ifsta->preq_queue.list);
++ifsta->preq_queue_len;
spin_unlock(&ifsta->mesh_preq_queue_lock);
if (time_after(jiffies, ifsta->last_preq + min_preq_int_jiff(sdata)))
queue_work(sdata->local->hw.workqueue, &ifsta->work);
else if (time_before(jiffies, ifsta->last_preq)) {
/* avoid long wait if did not send preqs for a long time
* and jiffies wrapped around
*/
ifsta->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
queue_work(sdata->local->hw.workqueue, &ifsta->work);
} else
mod_timer(&ifsta->mesh_path_timer, ifsta->last_preq +
min_preq_int_jiff(sdata));
}
/**
* mesh_path_start_discovery - launch a path discovery from the PREQ queue
*
* @dev: local mesh interface
*/
void mesh_path_start_discovery(struct net_device *dev)
{
struct ieee80211_sub_if_data *sdata =
IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_if_sta *ifsta = &sdata->u.sta;
struct mesh_preq_queue *preq_node;
struct mesh_path *mpath;
u8 ttl, dst_flags;
u32 lifetime;
spin_lock(&ifsta->mesh_preq_queue_lock);
if (!ifsta->preq_queue_len ||
time_before(jiffies, ifsta->last_preq +
min_preq_int_jiff(sdata))) {
spin_unlock(&ifsta->mesh_preq_queue_lock);
return;
}
preq_node = list_first_entry(&ifsta->preq_queue.list,
struct mesh_preq_queue, list);
list_del(&preq_node->list);
--ifsta->preq_queue_len;
spin_unlock(&ifsta->mesh_preq_queue_lock);
rcu_read_lock();
mpath = mesh_path_lookup(preq_node->dst, dev);
if (!mpath)
goto enddiscovery;
spin_lock_bh(&mpath->state_lock);
if (preq_node->flags & PREQ_Q_F_START) {
if (mpath->flags & MESH_PATH_RESOLVING) {
spin_unlock_bh(&mpath->state_lock);
goto enddiscovery;
} else {
mpath->flags &= ~MESH_PATH_RESOLVED;
mpath->flags |= MESH_PATH_RESOLVING;
mpath->discovery_retries = 0;
mpath->discovery_timeout = disc_timeout_jiff(sdata);
}
} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
mpath->flags & MESH_PATH_RESOLVED) {
mpath->flags &= ~MESH_PATH_RESOLVING;
spin_unlock_bh(&mpath->state_lock);
goto enddiscovery;
}
ifsta->last_preq = jiffies;
if (time_after(jiffies, ifsta->last_dsn_update +
net_traversal_jiffies(sdata)) ||
time_before(jiffies, ifsta->last_dsn_update)) {
++ifsta->dsn;
sdata->u.sta.last_dsn_update = jiffies;
}
lifetime = default_lifetime(sdata);
ttl = sdata->u.sta.mshcfg.dot11MeshTTL;
if (ttl == 0) {
sdata->u.sta.mshstats.dropped_frames_ttl++;
spin_unlock_bh(&mpath->state_lock);
goto enddiscovery;
}
if (preq_node->flags & PREQ_Q_F_REFRESH)
dst_flags = MP_F_DO;
else
dst_flags = MP_F_RF;
spin_unlock_bh(&mpath->state_lock);
mesh_path_sel_frame_tx(MPATH_PREQ, 0, dev->dev_addr,
cpu_to_le32(ifsta->dsn), dst_flags, mpath->dst,
cpu_to_le32(mpath->dsn), dev->broadcast, 0,
ttl, cpu_to_le32(lifetime), 0,
cpu_to_le32(ifsta->preq_id++), dev);
mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
enddiscovery:
rcu_read_unlock();
kfree(preq_node);
}
/**
* ieee80211s_lookup_nexthop - put the appropriate next hop on a mesh frame
*
* @next_hop: output argument for next hop address
* @skb: frame to be sent
* @dev: network device the frame will be sent through
*
* Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
* found, the function will start a path discovery and queue the frame so it is
* sent when the path is resolved. This means the caller must not free the skb
* in this case.
*/
int mesh_nexthop_lookup(u8 *next_hop, struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct sk_buff *skb_to_free = NULL;
struct mesh_path *mpath;
int err = 0;
rcu_read_lock();
mpath = mesh_path_lookup(skb->data, dev);
if (!mpath) {
mesh_path_add(skb->data, dev);
mpath = mesh_path_lookup(skb->data, dev);
if (!mpath) {
dev_kfree_skb(skb);
sdata->u.sta.mshstats.dropped_frames_no_route++;
err = -ENOSPC;
goto endlookup;
}
}
if (mpath->flags & MESH_PATH_ACTIVE) {
if (time_after(jiffies, mpath->exp_time -
msecs_to_jiffies(sdata->u.sta.mshcfg.path_refresh_time))
&& skb->pkt_type != PACKET_OTHERHOST
&& !(mpath->flags & MESH_PATH_RESOLVING)
&& !(mpath->flags & MESH_PATH_FIXED)) {
mesh_queue_preq(mpath,
PREQ_Q_F_START | PREQ_Q_F_REFRESH);
}
memcpy(next_hop, mpath->next_hop->addr,
ETH_ALEN);
} else {
if (!(mpath->flags & MESH_PATH_RESOLVING)) {
/* Start discovery only if it is not running yet */
mesh_queue_preq(mpath, PREQ_Q_F_START);
}
if (skb_queue_len(&mpath->frame_queue) >=
MESH_FRAME_QUEUE_LEN) {
skb_to_free = mpath->frame_queue.next;
skb_unlink(skb_to_free, &mpath->frame_queue);
}
skb_queue_tail(&mpath->frame_queue, skb);
if (skb_to_free)
mesh_path_discard_frame(skb_to_free, dev);
err = -ENOENT;
}
endlookup:
rcu_read_unlock();
return err;
}
void mesh_path_timer(unsigned long data)
{
struct ieee80211_sub_if_data *sdata;
struct mesh_path *mpath;
rcu_read_lock();
mpath = (struct mesh_path *) data;
mpath = rcu_dereference(mpath);
if (!mpath)
goto endmpathtimer;
spin_lock_bh(&mpath->state_lock);
sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
if (mpath->flags & MESH_PATH_RESOLVED ||
(!(mpath->flags & MESH_PATH_RESOLVING)))
mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
else if (mpath->discovery_retries < max_preq_retries(sdata)) {
++mpath->discovery_retries;
mpath->discovery_timeout *= 2;
mesh_queue_preq(mpath, 0);
} else {
mpath->flags = 0;
mpath->exp_time = jiffies;
mesh_path_flush_pending(mpath);
}
spin_unlock_bh(&mpath->state_lock);
endmpathtimer:
rcu_read_unlock();
}
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