Support multple lan clients from the same IP (#2452)

* Support multiple lam rooms from the same ip on different ports

* Make broadcast socket use SO_REUSEADDR

This allows multiple instances of the client to listen from broadcast messages at the same time on the same port

* Update duelclient.cpp

gframe/duelclient.cpp

@@ -34,7 +34,7 @@ mt19937 DuelClient::rnd;
 bool DuelClient::is_refreshing = false;
 int DuelClient::match_kill = 0;
 std::vector<HostPacket> DuelClient::hosts;
-std::set<unsigned int> DuelClient::remotes;
+std::set<std::pair<unsigned int, unsigned short>> DuelClient::remotes;
 event* DuelClient::resp_event = 0;
 
 bool DuelClient::StartClient(unsigned int ip, unsigned short port, bool create_game) {
@@ -4031,11 +4031,16 @@ void DuelClient::BroadcastReply(evutil_socket_t fd, short events, void * arg) {
 		socklen_t sz = sizeof(sockaddr_in);
 		char buf[256];
 		/*int ret = */recvfrom(fd, buf, 256, 0, (sockaddr*)&bc_addr, &sz);
-		unsigned int ipaddr = bc_addr.sin_addr.s_addr;
 		HostPacket* pHP = (HostPacket*)buf;
-		if(!is_closing && pHP->identifier == NETWORK_SERVER_ID && pHP->version == PRO_VERSION && remotes.find(ipaddr) == remotes.end() ) {
+		if(is_closing || pHP->identifier != NETWORK_SERVER_ID)
+			return;
+		if(pHP->version != PRO_VERSION)
+			return;
+		unsigned int ipaddr = bc_addr.sin_addr.s_addr;
+		const auto remote = std::make_pair(ipaddr, pHP->port);
+		if(remotes.find(remote) == remotes.end()) {
 			mainGame->gMutex.lock();
-			remotes.insert(ipaddr);
+			remotes.insert(remote);
 			pHP->ipaddr = ipaddr;
 			hosts.push_back(*pHP);
 			std::wstring hoststr;

gframe/duelclient.h

@@ -4,6 +4,7 @@
 #include "config.h"
 #include <vector>
 #include <set>
+#include <utility>
 #include <event2/event.h>
 #include <event2/listener.h>
 #include <event2/bufferevent.h>
@@ -76,7 +77,7 @@ protected:
 	static bool is_refreshing;
 	static int match_kill;
 	static event* resp_event;
-	static std::set<unsigned int> remotes;
+	static std::set<std::pair<unsigned int, unsigned short>> remotes;
 public:
 	static std::vector<HostPacket> hosts;
 	static void BeginRefreshHost();

gframe/netserver.cpp

@@ -42,6 +42,7 @@ bool NetServer::StartBroadcast() {
 	SOCKET udp = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 	BOOL opt = TRUE;
 	setsockopt(udp, SOL_SOCKET, SO_BROADCAST, (const char*)&opt, sizeof(BOOL));
+	setsockopt(udp, SOL_SOCKET, SO_REUSEADDR, (const char*)&opt, sizeof(BOOL));
 	sockaddr_in addr;
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;