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authorJulius Niedworok <julius.n@gmx.net>2019-03-28 23:01:06 +0300
committerJohannes Berg <johannes.berg@intel.com>2019-04-26 14:02:11 +0300
commit276d9e82e06cade9c4d081664ad63da1be971642 (patch)
treeb8013c4d064706e99c4187e5365242752d8b3b26 /net/mac80211/debugfs.c
parent5e280420916f9483ce7b483ccc378f3c7b5929ab (diff)
downloadlinux-276d9e82e06cade9c4d081664ad63da1be971642.tar.xz
mac80211: debugfs option to force TX status frames
At Technical University of Munich we use MAC 802.11 TX status frames to perform several measurements in MAC 802.11 setups. With ath based drivers this was possible until commit d94a461d7a7df6 ("ath9k: use ieee80211_tx_status_noskb where possible") as the driver ignored the IEEE80211_TX_CTL_REQ_TX_STATUS flag and always delivered tx_status frames. Since that commit, this behavior was changed and the driver now adheres to IEEE80211_TX_CTL_REQ_TX_STATUS. Due to performance reasons, IEEE80211_TX_CTL_REQ_TX_STATUS is not set for data frames from interfaces in managed mode. Hence, frames that are sent from a managed mode interface do never deliver tx_status frames. This remains true even if a monitor mode interface (the measurement interface) is added to the same ieee80211 physical device. Thus, there is no possibility for receiving tx_status frames for frames sent on an interface in managed mode, if the driver adheres to IEEE80211_TX_CTL_REQ_TX_STATUS. In order to force delivery of tx_status frames for research and debugging purposes, implement a debugfs option force_tx_status for ieee80211 physical devices. When this option is set for a physical device, IEEE80211_TX_CTL_REQ_TX_STATUS is enabled in all packets sent from that device. This option can be set via /sys/kernel/debug/ieee80211/<dev>/force_tx_status. The default is disabled. Co-developed-by: Charlie Groh <ga58taw@mytum.de> Signed-off-by: Charlie Groh <ga58taw@mytum.de> Signed-off-by: Julius Niedworok <julius.n@gmx.net> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/debugfs.c')
-rw-r--r--net/mac80211/debugfs.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index aa6f23e1a457..0d462206eef6 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -150,6 +150,58 @@ static const struct file_operations aqm_ops = {
.llseek = default_llseek,
};
+static ssize_t force_tx_status_read(struct file *file,
+ char __user *user_buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct ieee80211_local *local = file->private_data;
+ char buf[3];
+ int len = 0;
+
+ len = scnprintf(buf, sizeof(buf), "%d\n", (int)local->force_tx_status);
+
+ return simple_read_from_buffer(user_buf, count, ppos,
+ buf, len);
+}
+
+static ssize_t force_tx_status_write(struct file *file,
+ const char __user *user_buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct ieee80211_local *local = file->private_data;
+ char buf[3];
+ size_t len;
+
+ if (count > sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(buf, user_buf, count))
+ return -EFAULT;
+
+ buf[sizeof(buf) - 1] = '\0';
+ len = strlen(buf);
+ if (len > 0 && buf[len - 1] == '\n')
+ buf[len - 1] = 0;
+
+ if (buf[0] == '0' && buf[1] == '\0')
+ local->force_tx_status = 0;
+ else if (buf[0] == '1' && buf[1] == '\0')
+ local->force_tx_status = 1;
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static const struct file_operations force_tx_status_ops = {
+ .write = force_tx_status_write,
+ .read = force_tx_status_read,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
#ifdef CONFIG_PM
static ssize_t reset_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
@@ -383,6 +435,7 @@ void debugfs_hw_add(struct ieee80211_local *local)
DEBUGFS_ADD(hwflags);
DEBUGFS_ADD(user_power);
DEBUGFS_ADD(power);
+ DEBUGFS_ADD_MODE(force_tx_status, 0600);
if (local->ops->wake_tx_queue)
DEBUGFS_ADD_MODE(aqm, 0600);