[1/3] netdev: Remove improper use of netdev_connect_failed

Commit Message

Denis Kenzior Nov. 15, 2023, 12:05 a.m. UTC

When a roam event is received, iwd generates a firmware scan request and
notifies its event filter of the ROAMING condition.  In cases where the
firmware scan could not be started successfully, netdev_connect_failed
is invoked.  This is not a correct use of netev_connect_failed since it
doesn't actually disconnect the underlying netdev and the reflected
state becomes de-synchronized from the underlying kernel device.

The firmware scan request could currently fail for two reasons:
  1. nl80211 genl socket is in a bad state, or
  2. the scan context does not exist

Since both reasons are highly unlikely, simply use L_WARN instead.

The other two cases where netdev_connect_failed is used could only occur
if the kernel message is invalid.  The message is ignored in that case
and a warning is printed.

The situation described above also exists in netdev_get_fw_scan_cb. If
the scan could not be completed successfully, there's not much iwd can
do to recover.  Have iwd remain in roaming state and print an error.
---
 src/netdev.c | 35 +++++++++++------------------------
 1 file changed, 11 insertions(+), 24 deletions(-)

Comments

Denis Kenzior Nov. 15, 2023, 7:07 p.m. UTC | #1

On 11/14/23 18:05, Denis Kenzior wrote:
> When a roam event is received, iwd generates a firmware scan request and
> notifies its event filter of the ROAMING condition.  In cases where the
> firmware scan could not be started successfully, netdev_connect_failed
> is invoked.  This is not a correct use of netev_connect_failed since it
> doesn't actually disconnect the underlying netdev and the reflected
> state becomes de-synchronized from the underlying kernel device.
> 
> The firmware scan request could currently fail for two reasons:
>    1. nl80211 genl socket is in a bad state, or
>    2. the scan context does not exist
> 
> Since both reasons are highly unlikely, simply use L_WARN instead.
> 
> The other two cases where netdev_connect_failed is used could only occur
> if the kernel message is invalid.  The message is ignored in that case
> and a warning is printed.
> 
> The situation described above also exists in netdev_get_fw_scan_cb. If
> the scan could not be completed successfully, there's not much iwd can
> do to recover.  Have iwd remain in roaming state and print an error.
> ---
>   src/netdev.c | 35 +++++++++++------------------------
>   1 file changed, 11 insertions(+), 24 deletions(-)
> 

All applied.

Regards,
-Denis

Patch

diff --git a/src/netdev.c b/src/netdev.c
index ffd903740dd9..4a418b60abcf 100644
--- a/src/netdev.c
+++ b/src/netdev.c
@@ -4934,7 +4934,7 @@  static bool netdev_get_fw_scan_cb(int err, struct l_queue *bss_list,
 
 	if (err < 0) {
 		l_error("Failed to get scan after roam (%d)", err);
-		goto failed;
+		return false;
 	}
 
 	/*
@@ -4946,7 +4946,7 @@  static bool netdev_get_fw_scan_cb(int err, struct l_queue *bss_list,
 
 	if (!bss) {
 		l_error("Roam target BSS not found in scan results");
-		goto failed;
+		return false;
 	}
 
 	netdev->fw_roam_bss = bss;
@@ -4958,16 +4958,9 @@  static bool netdev_get_fw_scan_cb(int err, struct l_queue *bss_list,
 		return false;
 	}
 
-	if (netdev->sm) {
-		if (!eapol_start(netdev->sm))
-			goto failed;
-	}
-
-	return false;
+	if (netdev->sm)
+		L_WARN_ON(!eapol_start(netdev->sm));
 
-failed:
-	netdev_connect_failed(netdev, NETDEV_RESULT_ABORTED,
-					MMPDU_REASON_CODE_UNSPECIFIED);
 	return false;
 }
 
@@ -4998,8 +4991,8 @@  static void netdev_roam_event(struct l_genl_msg *msg, struct netdev *netdev)
 
 	netdev->operational = false;
 
-	if (!l_genl_attr_init(&attr, msg))
-		goto failed;
+	if (L_WARN_ON(!l_genl_attr_init(&attr, msg)))
+		return;
 
 	while (l_genl_attr_next(&attr, &type, &len, &data)) {
 		switch (type) {
@@ -5014,7 +5007,7 @@  static void netdev_roam_event(struct l_genl_msg *msg, struct netdev *netdev)
 
 	if (!mac) {
 		l_error("Failed to parse ATTR_MAC from CMD_ROAM");
-		goto failed;
+		return;
 	}
 
 	/* Handshake completed in firmware, just get the roamed BSS */
@@ -5031,20 +5024,14 @@  static void netdev_roam_event(struct l_genl_msg *msg, struct netdev *netdev)
 get_fw_scan:
 	handshake_state_set_authenticator_address(netdev->handshake, mac);
 
-	if (!scan_get_firmware_scan(netdev->wdev_id, netdev_get_fw_scan_cb,
-					netdev, NULL))
-		goto failed;
+	if (L_WARN_ON(!scan_get_firmware_scan(netdev->wdev_id,
+					netdev_get_fw_scan_cb,
+					netdev, NULL)))
+		return;
 
 	if (netdev->event_filter)
 		netdev->event_filter(netdev, NETDEV_EVENT_ROAMING,
 					NULL, netdev->user_data);
-
-	return;
-failed:
-	l_error("Failed to properly handle the ROAM event -- submit logs!");
-	netdev_connect_failed(netdev, NETDEV_RESULT_ABORTED,
-					MMPDU_REASON_CODE_UNSPECIFIED);
-
 }
 
 static void netdev_send_sa_query_delay(struct l_timeout *timeout,