From: Alexis Green <agreen@uniumwifi.com>
To: linux-wireless@vger.kernel.org
Cc: Jesse Jones <jjones@cococorp.com>
Subject: [PATCH] mac80211: Jitter HWMP MPATH reply frames to reduce collision, on dense networks.
Date: Tue, 21 Feb 2017 15:24:59 -0800 [thread overview]
Message-ID: <58ACCC4B.2090008@cococorp.com> (raw)
From: Jesse Jones <jjones@uniumwifi.com>
When more than one station hears a broadcast request, it is possible that
multiple devices will reply at the same time, potentially causing
collision. This patch helps reduce this issue.
Signed-off-by: Alexis Green <agreen@uniumwifi.com>
Signed-off-by: Benjamin Morgan <bmorgan@uniumwifi.com>
---
net/mac80211/ieee80211_i.h | 11 ++++
net/mac80211/iface.c | 58 +++++++++++++++++++++
net/mac80211/mesh.c | 2 +
net/mac80211/mesh_hwmp.c | 124 +++++++++++++++++++++++++++++++++++----------
4 files changed, 168 insertions(+), 27 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 159a1a7..f422897 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -330,6 +330,11 @@ struct mesh_preq_queue {
u8 flags;
};
+struct mesh_tx_queue {
+ struct list_head list;
+ struct sk_buff *skb;
+};
+
struct ieee80211_roc_work {
struct list_head list;
@@ -670,6 +675,11 @@ struct ieee80211_if_mesh {
spinlock_t mesh_preq_queue_lock;
struct mesh_preq_queue preq_queue;
int preq_queue_len;
+ /* Spinlock for MPATH frame tx queue */
+ spinlock_t mesh_tx_queue_lock;
+ struct mesh_tx_queue tx_queue;
+ int tx_queue_len;
+
struct mesh_stats mshstats;
struct mesh_config mshcfg;
atomic_t estab_plinks;
@@ -919,6 +929,7 @@ struct ieee80211_sub_if_data {
struct work_struct work;
struct sk_buff_head skb_queue;
+ struct delayed_work tx_work;
u8 needed_rx_chains;
enum ieee80211_smps_mode smps_mode;
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 40813dd..51d5cfa 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -778,6 +778,59 @@ static int ieee80211_open(struct net_device *dev)
return ieee80211_do_open(&sdata->wdev, true);
}
+static void flush_tx_skbs(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+ struct mesh_tx_queue *tx_node;
+
+ spin_lock_bh(&ifmsh->mesh_tx_queue_lock);
+
+ /* Note that this check is important because of the two-stage
+ * way that ieee80211_if_mesh is initialized.
+ */
+ if (ifmsh->tx_queue_len > 0) {
+ mhwmp_dbg(sdata, "flushing %d skbs", ifmsh->tx_queue_len);
+
+ while (!list_empty(&ifmsh->tx_queue.list)) {
+ tx_node = list_last_entry(&ifmsh->tx_queue.list,
+ struct mesh_tx_queue, list);
+ kfree_skb(tx_node->skb);
+ list_del(&tx_node->list);
+ kfree(tx_node);
+ }
+ ifmsh->tx_queue_len = 0;
+ }
+
+ spin_unlock_bh(&ifmsh->mesh_tx_queue_lock);
+}
+
+static void mesh_jittered_tx(struct work_struct *wk)
+{
+ struct ieee80211_sub_if_data *sdata =
+ container_of(
+ wk, struct ieee80211_sub_if_data,
+ tx_work.work);
+
+ struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+ struct mesh_tx_queue *tx_node;
+
+ spin_lock_bh(&ifmsh->mesh_tx_queue_lock);
+
+ list_for_each_entry(tx_node, &ifmsh->tx_queue.list, list) {
+ ieee80211_tx_skb(sdata, tx_node->skb);
+ }
+
+ while (!list_empty(&ifmsh->tx_queue.list)) {
+ tx_node = list_last_entry(&ifmsh->tx_queue.list,
+ struct mesh_tx_queue, list);
+ list_del(&tx_node->list);
+ kfree(tx_node);
+ }
+ ifmsh->tx_queue_len = 0;
+
+ spin_unlock_bh(&ifmsh->mesh_tx_queue_lock);
+}
+
static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
bool going_down)
{
@@ -881,6 +934,9 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);
+ flush_tx_skbs(sdata);
+ cancel_delayed_work_sync(&sdata->tx_work);
+
if (sdata->wdev.cac_started) {
chandef = sdata->vif.bss_conf.chandef;
WARN_ON(local->suspended);
@@ -1846,6 +1902,8 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
ieee80211_dfs_cac_timer_work);
INIT_DELAYED_WORK(&sdata->dec_tailroom_needed_wk,
ieee80211_delayed_tailroom_dec);
+ INIT_DELAYED_WORK(&sdata->tx_work,
+ mesh_jittered_tx);
for (i = 0; i < NUM_NL80211_BANDS; i++) {
struct ieee80211_supported_band *sband;
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index c28b0af..f0d3cd9 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -1381,6 +1381,8 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
ieee80211_mesh_path_root_timer,
(unsigned long) sdata);
INIT_LIST_HEAD(&ifmsh->preq_queue.list);
+ INIT_LIST_HEAD(&ifmsh->tx_queue.list);
+ spin_lock_init(&ifmsh->mesh_tx_queue_lock);
skb_queue_head_init(&ifmsh->ps.bc_buf);
spin_lock_init(&ifmsh->mesh_preq_queue_lock);
spin_lock_init(&ifmsh->sync_offset_lock);
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index b747c96..2f8ca4a 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -18,6 +18,7 @@
#define ARITH_SHIFT 8
#define MAX_PREQ_QUEUE_LEN 64
+#define MAX_TX_QUEUE_LEN 8
static void mesh_queue_preq(struct mesh_path *, u8);
@@ -98,13 +99,15 @@ enum mpath_frame_type {
static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
-static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
- const u8 *orig_addr, u32 orig_sn,
- u8 target_flags, const u8 *target,
- u32 target_sn, const u8 *da,
- u8 hop_count, u8 ttl,
- u32 lifetime, u32 metric, u32 preq_id,
- struct ieee80211_sub_if_data *sdata)
+static struct sk_buff *alloc_mesh_path_sel_frame(enum mpath_frame_type action,
+ u8 flags, const u8 *orig_addr,
+ u32 orig_sn, u8 target_flags,
+ const u8 *target,
+ u32 target_sn, const u8 *da,
+ u8 hop_count, u8 ttl,
+ u32 lifetime, u32 metric,
+ u32 preq_id,
+ struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
@@ -117,7 +120,7 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
hdr_len +
2 + 37); /* max HWMP IE */
if (!skb)
- return -1;
+ return NULL;
skb_reserve(skb, local->tx_headroom);
mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
memset(mgmt, 0, hdr_len);
@@ -153,7 +156,7 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
break;
default:
kfree_skb(skb);
- return -ENOTSUPP;
+ return NULL;
}
*pos++ = ie_len;
*pos++ = flags;
@@ -192,10 +195,72 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
pos += 4;
}
- ieee80211_tx_skb(sdata, skb);
- return 0;
+ return skb;
+}
+
+static void mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
+ const u8 *orig_addr, u32 orig_sn,
+ u8 target_flags, const u8 *target,
+ u32 target_sn, const u8 *da,
+ u8 hop_count, u8 ttl,
+ u32 lifetime, u32 metric, u32 preq_id,
+ struct ieee80211_sub_if_data *sdata)
+{
+ struct sk_buff *skb = alloc_mesh_path_sel_frame(action, flags,
+ orig_addr, orig_sn, target_flags, target, target_sn,
+ da, hop_count, ttl, lifetime, metric, preq_id, sdata);
+ if (skb)
+ ieee80211_tx_skb(sdata, skb);
}
+static void mesh_path_sel_frame_tx_jittered(enum mpath_frame_type action,
+ u8 flags, const u8 *orig_addr,
+ u32 orig_sn, u8 target_flags,
+ const u8 *target, u32 target_sn,
+ const u8 *da, u8 hop_count, u8 ttl,
+ u32 lifetime, u32 metric,
+ u32 preq_id,
+ struct ieee80211_sub_if_data *sdata)
+{
+ u32 jitter;
+ struct sk_buff *skb = alloc_mesh_path_sel_frame(action, flags,
+ orig_addr, orig_sn,
+ target_flags, target,
+ target_sn, da,
+ hop_count, ttl,
+ lifetime, metric,
+ preq_id, sdata);
+ if (skb) {
+ struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+ struct mesh_tx_queue *tx_node = kmalloc(
+ sizeof(struct mesh_tx_queue), GFP_ATOMIC);
+ if (!tx_node) {
+ mhwmp_dbg(sdata, "could not allocate mesh_hwmp tx node");
+ return;
+ }
+
+ spin_lock_bh(&ifmsh->mesh_tx_queue_lock);
+ if (ifmsh->tx_queue_len == MAX_TX_QUEUE_LEN) {
+ spin_unlock_bh(&ifmsh->mesh_tx_queue_lock);
+ kfree(tx_node);
+ kfree_skb(skb);
+ if (printk_ratelimit())
+ mhwmp_dbg(sdata, "mesh_hwmp tx node queue full");
+ return;
+ }
+
+ tx_node->skb = skb;
+ list_add_tail(&tx_node->list, &ifmsh->tx_queue.list);
+ ++ifmsh->tx_queue_len;
+ spin_unlock_bh(&ifmsh->mesh_tx_queue_lock);
+
+ jitter = prandom_u32() % 25;
+
+ ieee80211_queue_delayed_work(
+ &sdata->local->hw,
+ &sdata->tx_work, msecs_to_jiffies(jitter));
+ }
+}
/* Headroom is not adjusted. Caller should ensure that skb has sufficient
* headroom in case the frame is encrypted. */
@@ -611,11 +676,13 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
ttl = ifmsh->mshcfg.element_ttl;
if (ttl != 0) {
mhwmp_dbg(sdata, "replying to the PREQ\n");
- mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
- orig_sn, 0, target_addr,
- target_sn, mgmt->sa, 0, ttl,
- lifetime, target_metric, 0,
- sdata);
+ mesh_path_sel_frame_tx_jittered(MPATH_PREP, 0,
+ orig_addr, orig_sn,
+ 0, target_addr,
+ target_sn, mgmt->sa,
+ 0, ttl, lifetime,
+ target_metric, 0,
+ sdata);
} else {
ifmsh->mshstats.dropped_frames_ttl++;
}
@@ -643,10 +710,11 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
target_sn = PREQ_IE_TARGET_SN(preq_elem);
}
- mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
- orig_sn, target_flags, target_addr,
- target_sn, da, hopcount, ttl, lifetime,
- orig_metric, preq_id, sdata);
+ mesh_path_sel_frame_tx_jittered(MPATH_PREQ, flags, orig_addr,
+ orig_sn, target_flags,
+ target_addr, target_sn, da,
+ hopcount, ttl, lifetime,
+ orig_metric, preq_id, sdata);
if (!is_multicast_ether_addr(da))
ifmsh->mshstats.fwded_unicast++;
else
@@ -712,9 +780,10 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
target_sn = PREP_IE_TARGET_SN(prep_elem);
orig_sn = PREP_IE_ORIG_SN(prep_elem);
- mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
- target_addr, target_sn, next_hop, hopcount,
- ttl, lifetime, metric, 0, sdata);
+ mesh_path_sel_frame_tx_jittered(MPATH_PREP, flags, orig_addr, orig_sn,
+ 0, target_addr, target_sn, next_hop,
+ hopcount, ttl, lifetime, metric, 0,
+ sdata);
rcu_read_unlock();
sdata->u.mesh.mshstats.fwded_unicast++;
@@ -864,10 +933,11 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
ttl--;
if (ifmsh->mshcfg.dot11MeshForwarding) {
- mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
- orig_sn, 0, NULL, 0, broadcast_addr,
- hopcount, ttl, interval,
- metric + metric_txsta, 0, sdata);
+ mesh_path_sel_frame_tx_jittered(MPATH_RANN, flags, orig_addr,
+ orig_sn, 0, NULL, 0,
+ broadcast_addr, hopcount, ttl,
+ interval, metric + metric_txsta,
+ 0, sdata);
}
rcu_read_unlock();
reply other threads:[~2017-02-21 23:25 UTC|newest]
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