Fix: [Network] errno and strerror do not handle network errors on Windows

src/network/core/address.cpp

@@ -316,7 +316,7 @@ static SOCKET ConnectLoopProc(addrinfo *runp)
 
 	SOCKET sock = socket(runp->ai_family, runp->ai_socktype, runp->ai_protocol);
 	if (sock == INVALID_SOCKET) {
-		DEBUG(net, 1, "[%s] could not create %s socket: %s", type, family, strerror(errno));
+		DEBUG(net, 1, "[%s] could not create %s socket: %s", type, family, NetworkGetLastErrorString());
 		return INVALID_SOCKET;
 	}
 
@@ -331,7 +331,7 @@ static SOCKET ConnectLoopProc(addrinfo *runp)
 	if (err != 0)
 #endif
 	{
-		DEBUG(net, 1, "[%s] could not connect %s socket: %s", type, family, strerror(errno));
+		DEBUG(net, 1, "[%s] could not connect %s socket: %s", type, family, NetworkGetLastErrorString());
 		closesocket(sock);
 		return INVALID_SOCKET;
 	}
@@ -369,7 +369,7 @@ static SOCKET ListenLoopProc(addrinfo *runp)
 
 	SOCKET sock = socket(runp->ai_family, runp->ai_socktype, runp->ai_protocol);
 	if (sock == INVALID_SOCKET) {
-		DEBUG(net, 0, "[%s] could not create %s socket on port %s: %s", type, family, address, strerror(errno));
+		DEBUG(net, 0, "[%s] could not create %s socket on port %s: %s", type, family, address, NetworkGetLastErrorString());
 		return INVALID_SOCKET;
 	}
 
@@ -380,24 +380,24 @@ static SOCKET ListenLoopProc(addrinfo *runp)
 	int on = 1;
 	/* The (const char*) cast is needed for windows!! */
 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&on, sizeof(on)) == -1) {
-		DEBUG(net, 3, "[%s] could not set reusable %s sockets for port %s: %s", type, family, address, strerror(errno));
+		DEBUG(net, 3, "[%s] could not set reusable %s sockets for port %s: %s", type, family, address, NetworkGetLastErrorString());
 	}
 
 #ifndef __OS2__
 	if (runp->ai_family == AF_INET6 &&
 			setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&on, sizeof(on)) == -1) {
-		DEBUG(net, 3, "[%s] could not disable IPv4 over IPv6 on port %s: %s", type, address, strerror(errno));
+		DEBUG(net, 3, "[%s] could not disable IPv4 over IPv6 on port %s: %s", type, address, NetworkGetLastErrorString());
 	}
 #endif
 
 	if (bind(sock, runp->ai_addr, (int)runp->ai_addrlen) != 0) {
-		DEBUG(net, 1, "[%s] could not bind on %s port %s: %s", type, family, address, strerror(errno));
+		DEBUG(net, 1, "[%s] could not bind on %s port %s: %s", type, family, address, NetworkGetLastErrorString());
 		closesocket(sock);
 		return INVALID_SOCKET;
 	}
 
 	if (runp->ai_socktype != SOCK_DGRAM && listen(sock, 1) != 0) {
-		DEBUG(net, 1, "[%s] could not listen at %s port %s: %s", type, family, address, strerror(errno));
+		DEBUG(net, 1, "[%s] could not listen at %s port %s: %s", type, family, address, NetworkGetLastErrorString());
 		closesocket(sock);
 		return INVALID_SOCKET;
 	}

src/network/core/core.cpp

@@ -13,6 +13,7 @@
 #include "../../debug.h"
 #include "os_abstraction.h"
 #include "packet.h"
+#include "../../string_func.h"
 
 #include "../../safeguards.h"
 
@@ -48,6 +49,22 @@ void NetworkCoreShutdown()
 #endif
 }
 
+#if defined(_WIN32)
+/**
+ * Return the string representation of the given error from the OS's network functions.
+ * @param error The error number (from \c NetworkGetLastError()).
+ * @return The error message, potentially an empty string but never \c nullptr.
+ */
+const char *NetworkGetErrorString(int error)
+{
+	static char buffer[512];
+	if (FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, error,
+			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, sizeof(buffer), NULL) == 0) {
+		seprintf(buffer, lastof(buffer), "Unknown error %d", error);
+	}
+	return buffer;
+}
+#endif /* defined(_WIN32) */
 
 /**
  * Serializes the GRFIdentifier (GRF ID and MD5 checksum) to the packet

src/network/core/os_abstraction.h

@@ -23,9 +23,17 @@
 #include <ws2tcpip.h>
 #include <windows.h>
 
-#define GET_LAST_ERROR() WSAGetLastError()
+/**
+ * Get the last error code from any of the OS's network functions.
+ * What it returns and when it is reset, is implementation defined.
+ * @return The last error code.
+ */
+#define NetworkGetLastError() WSAGetLastError()
 #undef EWOULDBLOCK
 #define EWOULDBLOCK WSAEWOULDBLOCK
+
+const char *NetworkGetErrorString(int error);
+
 /* Windows has some different names for some types */
 typedef unsigned long in_addr_t;
 
@@ -51,7 +59,8 @@ typedef unsigned long in_addr_t;
 #	define INVALID_SOCKET -1
 #	define ioctlsocket ioctl
 #	define closesocket close
-#	define GET_LAST_ERROR() (errno)
+#	define NetworkGetLastError() (errno)
+#	define NetworkGetErrorString(error) (strerror(error))
 /* Need this for FIONREAD on solaris */
 #	define BSD_COMP
 
@@ -101,7 +110,8 @@ typedef unsigned long in_addr_t;
 #	define INVALID_SOCKET -1
 #	define ioctlsocket ioctl
 #	define closesocket close
-#	define GET_LAST_ERROR() (sock_errno())
+#	define NetworkGetLastError() (sock_errno())
+#	define NetworkGetErrorString(error) (strerror(error))
 
 /* Includes needed for OS/2 systems */
 #	include <types.h>
@@ -173,6 +183,15 @@ static inline socklen_t FixAddrLenForEmscripten(struct sockaddr_storage &address
 }
 #endif
 
+/**
+ * Return the string representation of the last error from the OS's network functions.
+ * @return The error message, potentially an empty string but never \c nullptr.
+ */
+static inline const char *NetworkGetLastErrorString()
+{
+	return NetworkGetErrorString(NetworkGetLastError());
+}
+
 /**
  * Try to set the socket into non-blocking mode.
  * @param d The socket to set the non-blocking more for.

src/network/core/tcp.cpp

@@ -86,7 +86,7 @@ SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
 	while ((p = this->packet_queue) != nullptr) {
 		res = p->TransferOut<int>(send, this->sock, 0);
 		if (res == -1) {
-			int err = GET_LAST_ERROR();
+			int err = NetworkGetLastError();
 			if (err != EWOULDBLOCK) {
 				/* Something went wrong.. close client! */
 				if (!closing_down) {
@@ -136,7 +136,7 @@ Packet *NetworkTCPSocketHandler::ReceivePacket()
 		while (p->RemainingBytesToTransfer() != 0) {
 			res = p->TransferIn<int>(recv, this->sock, 0);
 			if (res == -1) {
-				int err = GET_LAST_ERROR();
+				int err = NetworkGetLastError();
 				if (err != EWOULDBLOCK) {
 					/* Something went wrong... (104 is connection reset by peer) */
 					if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);
@@ -164,7 +164,7 @@ Packet *NetworkTCPSocketHandler::ReceivePacket()
 	while (p->RemainingBytesToTransfer() != 0) {
 		res = p->TransferIn<int>(recv, this->sock, 0);
 		if (res == -1) {
-			int err = GET_LAST_ERROR();
+			int err = NetworkGetLastError();
 			if (err != EWOULDBLOCK) {
 				/* Something went wrong... (104 is connection reset by peer) */
 				if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);

src/network/core/tcp_http.cpp

@@ -228,7 +228,7 @@ int NetworkHTTPSocketHandler::Receive()
 	for (;;) {
 		ssize_t res = recv(this->sock, (char *)this->recv_buffer + this->recv_pos, lengthof(this->recv_buffer) - this->recv_pos, 0);
 		if (res == -1) {
-			int err = GET_LAST_ERROR();
+			int err = NetworkGetLastError();
 			if (err != EWOULDBLOCK) {
 				/* Something went wrong... (104 is connection reset by peer) */
 				if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);

src/network/core/tcp_listen.h

@@ -64,7 +64,7 @@ public:
 					DEBUG(net, 1, "[%s] Banned ip tried to join (%s), refused", Tsocket::GetName(), entry.c_str());
 
 					if (p.TransferOut<int>(send, s, 0) < 0) {
-						DEBUG(net, 0, "send failed with error %d", GET_LAST_ERROR());
+						DEBUG(net, 0, "send failed with error %d", NetworkGetLastError());
 					}
 					closesocket(s);
 					break;
@@ -81,7 +81,7 @@ public:
 				p.PrepareToSend();
 
 				if (p.TransferOut<int>(send, s, 0) < 0) {
-					DEBUG(net, 0, "send failed with error %d", GET_LAST_ERROR());
+					DEBUG(net, 0, "send failed with error %d", NetworkGetLastError());
 				}
 				closesocket(s);
 

src/network/core/udp.cpp

@@ -94,7 +94,7 @@ void NetworkUDPSocketHandler::SendPacket(Packet *p, NetworkAddress *recv, bool a
 			/* Enable broadcast */
 			unsigned long val = 1;
 			if (setsockopt(s.second, SOL_SOCKET, SO_BROADCAST, (char *) &val, sizeof(val)) < 0) {
-				DEBUG(net, 1, "[udp] setting broadcast failed with: %i", GET_LAST_ERROR());
+				DEBUG(net, 1, "[udp] setting broadcast failed with: %i", NetworkGetLastError());
 			}
 		}
 
@@ -103,7 +103,7 @@ void NetworkUDPSocketHandler::SendPacket(Packet *p, NetworkAddress *recv, bool a
 		DEBUG(net, 7, "[udp] sendto(%s)", send.GetAddressAsString().c_str());
 
 		/* Check for any errors, but ignore it otherwise */
-		if (res == -1) DEBUG(net, 1, "[udp] sendto(%s) failed with: %i", send.GetAddressAsString().c_str(), GET_LAST_ERROR());
+		if (res == -1) DEBUG(net, 1, "[udp] sendto(%s) failed with: %i", send.GetAddressAsString().c_str(), NetworkGetLastError());
 
 		if (!all) break;
 	}