From 197542c7ec19b41e865be1e84c6c6898de8514d1 Mon Sep 17 00:00:00 2001
From: Perttu Ahola <celeron55@gmail.com>
Date: Mon, 26 Nov 2012 09:49:07 +0200
Subject: New PROTOCOL_VERSION scheme (allow client to support a range of
 versions)

---
 src/server.cpp | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

(limited to 'src/server.cpp')

diff --git a/src/server.cpp b/src/server.cpp
index ac243a29c..f4da73fa5 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -2037,11 +2037,22 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 			Read and check network protocol version
 		*/
 
-		u16 net_proto_version = 0;
+		u16 min_net_proto_version = 0;
 		if(datasize >= 2+1+PLAYERNAME_SIZE+PASSWORD_SIZE+2)
-		{
-			net_proto_version = readU16(&data[2+1+PLAYERNAME_SIZE+PASSWORD_SIZE]);
-		}
+			min_net_proto_version = readU16(&data[2+1+PLAYERNAME_SIZE+PASSWORD_SIZE]);
+
+		// Use min if version field doesn't exist (backwards compatibility)
+		u16 max_net_proto_version = min_net_proto_version;
+		if(datasize >= 2+1+PLAYERNAME_SIZE+PASSWORD_SIZE+2+2)
+			max_net_proto_version = readU16(&data[2+1+PLAYERNAME_SIZE+PASSWORD_SIZE+2]);
+
+		u16 net_proto_version = max_net_proto_version;
+		if(max_net_proto_version != SERVER_PROTOCOL_VERSION && min_net_proto_version <= SERVER_PROTOCOL_VERSION)
+			net_proto_version = SERVER_PROTOCOL_VERSION;
+
+		verbosestream<<"Server: "<<peer_id<<" Protocol version: min: "
+				<<min_net_proto_version<<", max: "<<max_net_proto_version
+				<<", chosen: "<<net_proto_version<<std::endl;
 
 		getClient(peer_id)->net_proto_version = net_proto_version;
 
@@ -2059,7 +2070,7 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 		
 		if(g_settings->getBool("strict_protocol_version_checking"))
 		{
-			if(net_proto_version != PROTOCOL_VERSION)
+			if(net_proto_version != SERVER_PROTOCOL_VERSION)
 			{
 				actionstream<<"Server: A mismatched client tried to connect"
 						<<" from "<<addr_s<<std::endl;
@@ -2068,7 +2079,7 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 						L"Server version is ")
 						+ narrow_to_wide(VERSION_STRING) + L",\n"
 						+ L"server's PROTOCOL_VERSION is "
-						+ narrow_to_wide(itos(PROTOCOL_VERSION))
+						+ narrow_to_wide(itos(SERVER_PROTOCOL_VERSION))
 						+ L", client's PROTOCOL_VERSION is "
 						+ narrow_to_wide(itos(net_proto_version))
 				);
@@ -2310,7 +2321,7 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 		}
 		
 		// Warnings about protocol version can be issued here
-		if(getClient(peer_id)->net_proto_version < PROTOCOL_VERSION)
+		if(getClient(peer_id)->net_proto_version < SERVER_PROTOCOL_VERSION)
 		{
 			SendChatMessage(peer_id, L"# Server: WARNING: YOUR CLIENT IS OLD AND MAY WORK PROPERLY WITH THIS SERVER!");
 		}
-- 
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