diff -r ddcdedd3330b -r 2bc61f8841a1 project_files/frontlib/socket.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/project_files/frontlib/socket.c	Sun Oct 28 15:12:37 2012 +0100
@@ -0,0 +1,191 @@
+/*
+ * Hedgewars, a free turn based strategy game
+ * Copyright (C) 2012 Simeon Maxein <smaxein@googlemail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include "socket.h"
+#include "util/logging.h"
+#include "util/util.h"
+#include <stdlib.h>
+#include <SDL_net.h>
+#include <time.h>
+
+struct _flib_tcpsocket {
+	TCPsocket sock;
+	SDLNet_SocketSet sockset;
+};
+
+struct _flib_acceptor {
+	TCPsocket sock;
+	uint16_t port;
+};
+
+static uint32_t getPeerIp(TCPsocket sock) {
+	IPaddress *addr = SDLNet_TCP_GetPeerAddress(sock);
+	return SDLNet_Read32(&addr->host);
+}
+
+static bool connectionIsLocal(TCPsocket sock) {
+	return getPeerIp(sock) == (uint32_t)((127UL<<24)+1); // 127.0.0.1
+}
+
+static flib_tcpsocket *createSocket(TCPsocket sdlsock) {
+	flib_tcpsocket *result = flib_calloc(1, sizeof(flib_tcpsocket));
+	if(result) {
+		result->sock = sdlsock;
+		result->sockset = SDLNet_AllocSocketSet(1);
+
+		if(!result->sockset) {
+			flib_log_e("Can't allocate socket: Out of memory!");
+			SDLNet_FreeSocketSet(result->sockset);
+			free(result);
+			result = NULL;
+		} else {
+			SDLNet_AddSocket(result->sockset, (SDLNet_GenericSocket)result->sock);
+		}
+	}
+	return result;
+}
+
+TCPsocket listen(uint16_t port) {
+	IPaddress addr;
+	addr.host = INADDR_ANY;
+	SDLNet_Write16(port, &addr.port);
+	TCPsocket sock = SDLNet_TCP_Open(&addr);
+	if(!sock) {
+		flib_log_w("Unable to listen on port %u: %s", (unsigned)port, SDLNet_GetError());
+	}
+	return sock;
+}
+
+flib_acceptor *flib_acceptor_create(uint16_t port) {
+	flib_acceptor *result = flib_calloc(1, sizeof(flib_acceptor));
+	if(result) {
+		if(port > 0) {
+			result->port = port;
+			result->sock = listen(result->port);
+		} else {
+			/* SDL_net does not seem to have a way to listen on a random unused port
+			   and find out which port that is, so let's try to find one ourselves. */
+			srand(time(NULL));
+			for(int i=0; !result->sock && i<1000; i++) {
+				// IANA suggests using ports in the range 49152-65535 for things like this
+				result->port = 49152+(rand()%(65535-49152));
+				result->sock = listen(result->port);
+			}
+		}
+		if(!result->sock) {
+			flib_log_e("Failed to create acceptor.");
+			free(result);
+			result = NULL;
+		}
+	}
+	return result;
+}
+
+uint16_t flib_acceptor_listenport(flib_acceptor *acceptor) {
+	if(!acceptor) {
+		flib_log_e("Call to flib_acceptor_listenport with acceptor==null");
+		return 0;
+	}
+	return acceptor->port;
+}
+
+void flib_acceptor_close(flib_acceptor *acceptor) {
+	if(acceptor) {
+		SDLNet_TCP_Close(acceptor->sock);
+		free(acceptor);
+	}
+}
+
+flib_tcpsocket *flib_socket_accept(flib_acceptor *acceptor, bool localOnly) {
+	flib_tcpsocket *result = NULL;
+	if(!acceptor) {
+		flib_log_e("Call to flib_socket_accept with acceptor==null");
+	} else {
+		TCPsocket sock = NULL;
+		while(!result && (sock = SDLNet_TCP_Accept(acceptor->sock))) {
+			if(localOnly && !connectionIsLocal(sock)) {
+				flib_log_i("Rejected nonlocal connection attempt from %s", flib_format_ip(getPeerIp(sock)));
+			} else {
+				result = createSocket(sock);
+			}
+			if(!result) {
+				SDLNet_TCP_Close(sock);
+			}
+		}
+	}
+	return result;
+}
+
+flib_tcpsocket *flib_socket_connect(const char *host, uint16_t port) {
+	flib_tcpsocket *result = NULL;
+	if(!host || port==0) {
+		flib_log_e("Invalid parameter in flib_socket_connect");
+	} else {
+		IPaddress ip;
+		if(SDLNet_ResolveHost(&ip,host,port)==-1) {
+		   flib_log_e("SDLNet_ResolveHost: %s\n", SDLNet_GetError());
+		} else {
+			TCPsocket sock=SDLNet_TCP_Open(&ip);
+			if(!sock) {
+				flib_log_e("SDLNet_TCP_Open: %s\n", SDLNet_GetError());
+			} else {
+				result = createSocket(sock);
+				if(result) {
+					sock = NULL;
+				}
+			}
+			SDLNet_TCP_Close(sock);
+		}
+	}
+	return result;
+}
+
+void flib_socket_close(flib_tcpsocket *sock) {
+	if(sock) {
+		SDLNet_DelSocket(sock->sockset, (SDLNet_GenericSocket)sock->sock);
+		SDLNet_TCP_Close(sock->sock);
+		SDLNet_FreeSocketSet(sock->sockset);
+		free(sock);
+	}
+}
+
+int flib_socket_nbrecv(flib_tcpsocket *sock, void *data, int maxlen) {
+	if(!sock || (maxlen>0 && !data)) {
+		flib_log_e("Call to flib_socket_nbrecv with sock==null or data==null");
+		return -1;
+	}
+	int readySockets = SDLNet_CheckSockets(sock->sockset, 0);
+	if(readySockets>0) {
+		int size = SDLNet_TCP_Recv(sock->sock, data, maxlen);
+		return size>0 ? size : -1;
+	} else if(readySockets==0) {
+		return 0;
+	} else {
+		flib_log_e("Error in select system call: %s", SDLNet_GetError());
+		return -1;
+	}
+}
+
+int flib_socket_send(flib_tcpsocket *sock, const void *data, int len) {
+	if(!sock || (len>0 && !data)) {
+		flib_log_e("Call to flib_socket_send with sock==null or data==null");
+		return -1;
+	}
+	return SDLNet_TCP_Send(sock->sock, data, len);
+}