mac80211: don't invalidate SN on discovery failure

From: Jesse Jones <[email protected]>

The 2012 spec mentions that path SNs can be invalid when created (see section 13.10.8.4 table 13-9) but AFAICT never talks about invalidating SNs. Which makes sense: if we have figured out the path to a target at a certain SN then we want to remember that fact. Failing to do so can lead to routing loops because if we don't have a valid SN then we have no way of knowing whether an incoming path message leads to or away from the target.

However currently when discovery fails we zero out mpath->flags which clears MESH_PATH_SN_VALID. This patch fixes that so that only the discovery relevant flags are cleared.

---

index 085edc1..1d849be
@@ -1176,7 +1176,8 @@ void mesh_path_timer(unsigned long data)
 		spin_unlock_bh(&mpath->state_lock);
 		mesh_queue_preq(mpath, 0);
 	} else {
-		mpath->flags = 0;
+		mpath->flags &= ~(MESH_PATH_RESOLVING |
+			MESH_PATH_RESOLVED | MESH_PATH_REQ_QUEUED);
 		mpath->exp_time = jiffies;
 		spin_unlock_bh(&mpath->state_lock);
 		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {

Applied; I fixed the indentation a bit.

Also, please mention "mesh" in the future in the subject of your patches, it makes it easier to pick out.

johannes