From 45f95ecf35994912fe6a805467715a274c52976c Mon Sep 17 00:00:00 2001
From: James Prestwood <prestwoj@gmail.com>
Date: Tue, 6 Sep 2022 12:22:06 -0700
Subject: [PATCH] netdev: allow powered address change

Support for MAC address changes while powered was recently added to
mac80211. This avoids the need to power down the device which both
saves time as well as preserves any allowed frequencies which may
have been disabled if the device powered down.

The code path for changing the address was reused but now just the
'up' callback will be provided directly to l_rtnl_set_mac. Since
there aren't multiple stages of callbacks the rtnl_data structure
isn't strictly needed, but the code looks cleaner and more
consistent between the powered/non-powered code paths.

The comment/debug error print was also updated to be more general
between the two MAC change code paths.
---
 src/netdev.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/src/netdev.c b/src/netdev.c
index 3cc34fcd..3cd3e4ef 100644
--- a/src/netdev.c
+++ b/src/netdev.c
@@ -3601,12 +3601,8 @@ static void netdev_mac_change_failed(struct netdev *netdev,
 
 		goto failed;
 	} else {
-		/*
-		 * If the interface is up we can still try and connect. This
-		 * is a very rare case and most likely will never happen.
-		 */
-		l_info("Interface still up after failing to change the MAC, "
-			"continuing with connection");
+		/* If the interface is up we can still try and connect */
+		l_info("Failed to change the MAC, continuing with connection");
 		if (netdev_begin_connection(netdev) < 0)
 			goto failed;
 
@@ -3641,8 +3637,8 @@ static void netdev_mac_power_up_cb(int error, uint16_t type,
 	netdev->mac_change_cmd_id = 0;
 
 	if (error) {
-		l_error("Error taking interface %u up for per-network MAC "
-			"generation: %s", netdev->index, strerror(-error));
+		l_error("Error changing per-network MAC on interface %u: %s",
+			netdev->index, strerror(-error));
 		netdev_mac_change_failed(netdev, req, error);
 		return;
 	}
@@ -3673,8 +3669,6 @@ static void netdev_mac_power_down_cb(int error, uint16_t type,
 		return;
 	}
 
-	l_debug("Setting generated address on ifindex: %d to: "MAC,
-					netdev->index, MAC_STR(req->addr));
 	netdev->mac_change_cmd_id = l_rtnl_set_mac(rtnl, netdev->index,
 					req->addr, true,
 					netdev_mac_power_up_cb, req,
@@ -3713,6 +3707,8 @@ static int netdev_start_powered_mac_change(struct netdev *netdev)
 {
 	struct rtnl_data *req;
 	uint8_t new_addr[6];
+	bool powered = wiphy_has_ext_feature(netdev->wiphy,
+				NL80211_EXT_FEATURE_POWERED_ADDR_CHANGE);
 
 	/* No address set in handshake, use per-network MAC generation */
 	if (l_memeqzero(netdev->handshake->spa, ETH_ALEN))
@@ -3734,9 +3730,16 @@ static int netdev_start_powered_mac_change(struct netdev *netdev)
 	req->ref++;
 	memcpy(req->addr, new_addr, sizeof(req->addr));
 
-	netdev->mac_change_cmd_id = l_rtnl_set_powered(rtnl, netdev->index,
-					false, netdev_mac_power_down_cb,
-					req, netdev_mac_destroy);
+	if (powered)
+		netdev->mac_change_cmd_id = l_rtnl_set_mac(rtnl, netdev->index,
+						req->addr, false,
+						netdev_mac_power_up_cb, req,
+						netdev_mac_destroy);
+	else
+		netdev->mac_change_cmd_id = l_rtnl_set_powered(rtnl,
+						netdev->index, false,
+						netdev_mac_power_down_cb, req,
+						netdev_mac_destroy);
 
 	if (!netdev->mac_change_cmd_id) {
 		l_free(req);
@@ -3744,6 +3747,10 @@ static int netdev_start_powered_mac_change(struct netdev *netdev)
 		return -EIO;
 	}
 
+	l_debug("Setting generated address on ifindex: %d to: "MAC" (%s)",
+					netdev->index, MAC_STR(req->addr),
+					powered ? "powered" : "power-down");
+
 	return 0;
 }