From 2127cb654fcff1674de06dfbf8ec43574ce69cf1 Mon Sep 17 00:00:00 2001
From: George Hazan <ghazan@miranda.im>
Date: Thu, 22 Oct 2020 21:39:39 +0300
Subject: EMLanProto:

- fixes #2599 (Em-LAN: binds to localhost);
- code cleaning;
- version bump;
---
 protocols/EmLanProto/src/lan.cpp | 59 +++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 22 deletions(-)

(limited to 'protocols/EmLanProto/src/lan.cpp')

diff --git a/protocols/EmLanProto/src/lan.cpp b/protocols/EmLanProto/src/lan.cpp
index d7737b2479..157470f2b0 100644
--- a/protocols/EmLanProto/src/lan.cpp
+++ b/protocols/EmLanProto/src/lan.cpp
@@ -5,12 +5,9 @@
 
 CLan::CLan()
 {
-	m_income = INVALID_SOCKET;
-	m_filesoc = INVALID_SOCKET;
-	m_status = LS_OK;
-	m_mode = LM_OFF;
-	m_hListenThread = nullptr;
-	m_hAcceptTCPThread = nullptr;
+	memset(&m_curAddr, 0, sizeof(m_curAddr));
+	memset(&m_hostAddr, 0, sizeof(m_hostAddr));
+
 	Startup();
 }
 
@@ -19,6 +16,36 @@ CLan::~CLan()
 	Shutdown();
 }
 
+bool CLan::ResetInterfaces()
+{
+	char hostname[256];
+	if (gethostname(hostname, 256) != 0) {
+		m_status = LS_CANT_GET_HOSTADDR;
+		return false;
+	}
+
+	int hostAddrCount = 0;
+	in_addr hostAddr[MAX_INTERNAL_IP];
+
+	hostent *host = gethostbyname(hostname);
+	char **pAddr = host->h_addr_list;
+
+	while (*pAddr && hostAddrCount < MAX_INTERNAL_IP) {
+		in_addr addr;
+		addr.S_un.S_addr = *((u_long *)(*pAddr));
+		hostAddr[hostAddrCount++] = addr;
+		pAddr++;
+	}
+
+	// nothing changed? return false
+	if (m_hostAddrCount == hostAddrCount && !memcmp(m_hostAddr, hostAddr, sizeof(hostAddr)))
+		return false;
+
+	m_hostAddrCount = hostAddrCount;
+	memcpy(m_hostAddr, hostAddr, sizeof(hostAddr));
+	return true;
+}
+
 void CLan::Startup()
 {
 	WSADATA wsa;
@@ -26,22 +53,7 @@ void CLan::Startup()
 		m_status = LS_OK;
 		m_mode = LM_ON;
 
-		char hostname[256];
-		if (gethostname(hostname, 256) == 0) {
-			hostent* host = gethostbyname(hostname);
-			char** pAddr = host->h_addr_list;
-			m_hostAddrCount = 0;
-			while (*pAddr && m_hostAddrCount < MAX_INTERNAL_IP) {
-				in_addr addr;
-				addr.S_un.S_addr = *((u_long*)(*pAddr));
-				m_hostAddr[m_hostAddrCount++] = addr;
-				pAddr++;
-			}
-			m_curAddr = m_hostAddr[0];
-		}
-		else {
-			m_status = LS_CANT_GET_HOSTADDR;
-		}
+		ResetInterfaces();
 	}
 	else {
 		m_status = LS_OK;
@@ -91,6 +103,9 @@ void CLan::StartListen()
 	if (m_mode != LM_ON)
 		return;
 
+	if (m_curAddr.S_un.S_addr == 0)
+		return;
+
 	m_income = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 	m_filesoc = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	if (m_income == INVALID_SOCKET || m_filesoc == INVALID_SOCKET) {
-- 
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