From 4165224885aebb9f78ac327a241753dcb3dfeba7 Mon Sep 17 00:00:00 2001
From: "Roger A. Light" <roger@atchoo.org>
Date: Tue, 19 Jan 2021 10:16:06 +0000
Subject: [PATCH] Fix reloading of listeners where multiple listeners have the
 same port.

This is only possible where they have different bind addresses.

Closes #2029. Thanks to Simon Aldrich.
---
 ChangeLog.txt |  2 ++
 src/conf.c    | 17 +++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/ChangeLog.txt b/ChangeLog.txt
index f818c003ab..02ceae9a1a 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -7,6 +7,8 @@ Broker:
 - Add notes that libsystemd-dev or similar is needed if building with systemd
   support. Closes #2019.
 - Improve logging in obscure cases when a client disconnects. Closes #2017.
+- Fix reloading of listeners where multiple listeners have been defined with
+  the same port but different bind addresses. Closes #2029.
 
 Apps:
 - Allow command line arguments to override config file options in
diff --git a/src/conf.c b/src/conf.c
index 611a62035b..9c9de4f479 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -1417,8 +1417,21 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, struct
 							{
 								for(i=0; i<config->listener_count; i++){
 									if(config->listeners[i].port == tmp_int){
-										cur_listener = &config->listeners[i];
-										break;
+										/* Now check we have a matching bind address, if defined */
+										if(config->listeners[i].host){
+											if(token && !strcmp(config->listeners[i].host, token)){
+												/* They both have a bind address, and they match */
+												cur_listener = &config->listeners[i];
+												break;
+											}
+										}else{
+											if(token == NULL){
+												/* Neither this config nor the new config have a bind address,
+												 * so they match. */
+												cur_listener = &config->listeners[i];
+												break;
+											}
+										}
 									}
 								}
 							}