Fixed an issue where sometimes a player unable to join a host on Warriors Orochi 2 (should also fix similar issue on other games that use PDP/UDP on Windows)

Core/HLE/proAdhoc.cpp

@@ -1982,6 +1982,19 @@ int setSockReuseAddrPort(int sock) {
 	return setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&opt, sizeof(opt));
 }
 
+int setUDPConnReset(int udpsock, bool enabled) {
+	// On Windows: Connection Reset error on UDP could cause a strange behavior https://stackoverflow.com/questions/34242622/windows-udp-sockets-recvfrom-fails-with-error-10054
+#if defined(_WIN32)
+#if !defined(SIO_UDP_CONNRESET)
+#define SIO_UDP_CONNRESET _WSAIOW(IOC_VENDOR, 12)
+#endif
+	BOOL bNewBehavior = enabled;
+	DWORD dwBytesReturned = 0;
+	return WSAIoctl(udpsock, SIO_UDP_CONNRESET, &bNewBehavior, sizeof bNewBehavior, NULL, 0, &dwBytesReturned, NULL, NULL);
+#endif
+	return -1;
+}
+
 #if !defined(TCP_KEEPIDLE)
 #define TCP_KEEPIDLE	TCP_KEEPALIVE //TCP_KEEPIDLE on Linux is equivalent to TCP_KEEPALIVE on macOS
 #endif

Core/HLE/proAdhoc.h

@@ -1317,6 +1317,11 @@ int setSockNoSIGPIPE(int sock, int flag);
 */
 int setSockReuseAddrPort(int sock);
 
+/*
+* Set Socket Connection Reset on UDP (which could cause a strange behavior)
+*/
+int setUDPConnReset(int udpsock, bool enabled);
+
 /*
 * Set Socket KeepAlive (opt = SO_KEEPALIVE)
 */

Core/HLE/sceNetAdhoc.cpp

@@ -1240,6 +1240,9 @@ static int sceNetAdhocPdpCreate(const char *mac, int port, int bufferSize, u32 f
 					// Enable Port Re-use, this will allow binding to an already used port, but only one of them can read the data (shared receive buffer?)
 					setSockReuseAddrPort(usocket);
 
+					// Disable Connection Reset error on UDP to avoid strange behavior https://stackoverflow.com/questions/34242622/windows-udp-sockets-recvfrom-fails-with-error-10054
+					setUDPConnReset(usocket, false);
+
 					// Binding Information for local Port
 					sockaddr_in addr;
 					addr.sin_family = AF_INET;
@@ -2923,7 +2926,7 @@ static int sceNetAdhocGetPdpStat(u32 structSize, u32 structAddr) {
 				// Valid Socket Entry
 				auto sock = adhocSockets[j];
 				if (sock != NULL && sock->type == SOCK_PDP) {
-					// Set available bytes to be received. With FIOREAD There might be lingering 1 byte in recv buffer when remote peer's socket got closed (ie. Warriors Orochi 2)
+					// Set available bytes to be received. With FIOREAD There might be ghosting 1 byte in recv buffer when remote peer's socket got closed (ie. Warriors Orochi 2) Attempting to recv this ghost 1 byte will result to socket error 10054 (may need to disable SIO_UDP_CONNRESET error)
 					sock->data.pdp.rcv_sb_cc = getAvailToRecv(sock->data.pdp.id);
 
 					// Copy Socket Data from Internal Memory