From 35544e108183408424d0e1c9b15c4c954db9637e Mon Sep 17 00:00:00 2001
From: Owen <owen@txv.io>
Date: Fri, 5 Dec 2025 12:05:48 -0500
Subject: [PATCH] Fix changing alias

Former-commit-id: 039110647705b9a23fdc1fed7d3b02a75d2a3739
---
 olm/olm.go       | 18 ++++++++++--------
 peers/manager.go | 22 +++++++++++++++++-----
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/olm/olm.go b/olm/olm.go
index 7f52ce9..853bac9 100644
--- a/olm/olm.go
+++ b/olm/olm.go
@@ -670,20 +670,22 @@ func StartTunnel(config TunnelConfig) {
 			}
 		}
 
-		// Remove old aliases
-		for _, alias := range updateSubnetsData.OldAliases {
-			if err := peerManager.RemoveAlias(updateSubnetsData.SiteId, alias.Alias); err != nil {
-				logger.Error("Failed to remove alias %s: %v", alias.Alias, err)
-			}
-		}
-
-		// Add new aliases
+		// Add new aliases BEFORE removing old ones to preserve shared IP addresses
+		// This ensures that if an old and new alias share the same IP, the IP won't be
+		// temporarily removed from the allowed IPs list
 		for _, alias := range updateSubnetsData.NewAliases {
 			if err := peerManager.AddAlias(updateSubnetsData.SiteId, alias); err != nil {
 				logger.Error("Failed to add alias %s: %v", alias.Alias, err)
 			}
 		}
 
+		// Remove old aliases after new ones are added
+		for _, alias := range updateSubnetsData.OldAliases {
+			if err := peerManager.RemoveAlias(updateSubnetsData.SiteId, alias.Alias); err != nil {
+				logger.Error("Failed to remove alias %s: %v", alias.Alias, err)
+			}
+		}
+
 		logger.Info("Successfully updated remote subnets and aliases for peer %d", updateSubnetsData.SiteId)
 	})
 
diff --git a/peers/manager.go b/peers/manager.go
index 78681e1..f21d117 100644
--- a/peers/manager.go
+++ b/peers/manager.go
@@ -661,14 +661,26 @@ func (pm *PeerManager) RemoveAlias(siteId int, aliasName string) error {
 		}
 	}
 
-	// remove the allowed IP for the alias
-	if err := pm.removeAllowedIp(siteId, aliasToRemove.AliasAddress+"/32"); err != nil {
-		return err
-	}
-
 	peer.Aliases = newAliases
 	pm.peers[siteId] = peer
 
+	// Check if any other alias is still using this IP address before removing from allowed IPs
+	ipStillInUse := false
+	aliasIP := aliasToRemove.AliasAddress + "/32"
+	for _, a := range newAliases {
+		if a.AliasAddress+"/32" == aliasIP {
+			ipStillInUse = true
+			break
+		}
+	}
+
+	// Only remove the allowed IP if no other alias is using it
+	if !ipStillInUse {
+		if err := pm.removeAllowedIp(siteId, aliasIP); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }