From 4f9a7d31d3415951fa9bef3b23e3f81c5defd66b Mon Sep 17 00:00:00 2001
From: Hamish Coleman <hamish@zot.org>
Date: Wed, 21 Jun 2023 18:23:34 +0100
Subject: [PATCH] Fix bug in returned interface address

---
 include/edge_utils_win32.h | 3 +--
 src/edge_utils.c           | 2 +-
 src/edge_utils_win32.c     | 4 ++--
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/include/edge_utils_win32.h b/include/edge_utils_win32.h
index 09f8366..caf75eb 100644
--- a/include/edge_utils_win32.h
+++ b/include/edge_utils_win32.h
@@ -43,8 +43,7 @@ struct tunread_arg {
 };
 
 extern HANDLE startTunReadThread (struct tunread_arg *arg);
-int get_best_interface_ip (n2n_edge_t * eee, dec_ip_str_t ip_addr);
-
+int get_best_interface_ip (n2n_edge_t * eee, dec_ip_str_t *ip_addr);
 
 #endif /* WIN32 */
 
diff --git a/src/edge_utils.c b/src/edge_utils.c
index 8d6568a..e560b24 100644
--- a/src/edge_utils.c
+++ b/src/edge_utils.c
@@ -1184,7 +1184,7 @@ static void check_join_multicast_group (n2n_edge_t *eee) {
             mreq.imr_multiaddr.s_addr = inet_addr(N2N_MULTICAST_GROUP);
 #ifdef WIN32
             dec_ip_str_t ip_addr;
-            get_best_interface_ip(eee, ip_addr);
+            get_best_interface_ip(eee, &ip_addr);
             mreq.imr_interface.s_addr = inet_addr(ip_addr);
 #else
             mreq.imr_interface.s_addr = htonl(INADDR_ANY);
diff --git a/src/edge_utils_win32.c b/src/edge_utils_win32.c
index a32e06c..786968e 100644
--- a/src/edge_utils_win32.c
+++ b/src/edge_utils_win32.c
@@ -51,7 +51,7 @@ HANDLE startTunReadThread (struct tunread_arg *arg) {
 
 
 
-int get_best_interface_ip (n2n_edge_t * eee, dec_ip_str_t ip_addr){
+int get_best_interface_ip (n2n_edge_t * eee, dec_ip_str_t *ip_addr){
     DWORD interface_index = -1;
     DWORD dwRetVal = 0;
     PIP_ADAPTER_INFO pAdapterInfo = NULL, pAdapter = NULL;
@@ -94,7 +94,7 @@ int get_best_interface_ip (n2n_edge_t * eee, dec_ip_str_t ip_addr){
             traceEvent(TRACE_DEBUG, "IP Address:    %s\n", pAdapter->IpAddressList.IpAddress.String);
             traceEvent(TRACE_DEBUG, "IP Mask:       %s\n", pAdapter->IpAddressList.IpMask.String);
             traceEvent(TRACE_DEBUG, "Gateway:       %s\n", pAdapter->GatewayList.IpAddress.String);
-            strncpy(ip_addr, pAdapter->IpAddressList.IpAddress.String, sizeof(dec_ip_str_t)-1);
+            strncpy(ip_addr, pAdapter->IpAddressList.IpAddress.String, sizeof(*ip_addr));
         }
     } else {
         traceEvent(TRACE_WARNING, "GetAdaptersInfo failed with error: %d\n", dwRetVal);