--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/project_files/frontlib/socket.c	Sun Jun 03 01:24:18 2012 +0200
@@ -0,0 +1,149 @@
+#include "socket.h"
+#include "logging.h"
+#include <stdlib.h>
+#include <SDL_net.h>
+#include <time.h>
+
+typedef struct _flib_tcpsocket {
+	TCPsocket sock;
+	SDLNet_SocketSet sockset;
+} _flib_tcpsocket;
+
+typedef struct _flib_acceptor {
+	TCPsocket sock;
+	uint16_t port;
+} _flib_acceptor;
+
+static uint32_t get_peer_ip(TCPsocket sock) {
+	IPaddress *addr = SDLNet_TCP_GetPeerAddress(sock);
+	return SDLNet_Read32(&addr->host);
+}
+
+static bool connection_is_local(TCPsocket sock) {
+	return get_peer_ip(sock) == (uint32_t)((127UL<<24)+1); // 127.0.0.1
+}
+
+flib_acceptor flib_acceptor_create(uint16_t port) {
+	flib_acceptor result = malloc(sizeof(_flib_acceptor));
+	if(!result) {
+		flib_log_e("Out of memory!");
+		return NULL;
+	}
+
+	IPaddress addr;
+	addr.host = INADDR_ANY;
+
+	if(port > 0) {
+		result->port = port;
+		SDLNet_Write16(port, &addr.port);
+		result->sock = SDLNet_TCP_Open(&addr);
+		if(result->sock) {
+			return result;
+		} else {
+			flib_log_e("Unable to listen on port %u: %s", port, SDLNet_GetError());
+			free(result);
+			return NULL;
+		}
+	} 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. */
+		// TODO: Is socket binding fail-fast on all platforms?
+		srand(time(NULL));
+		rand();
+		for(int i=0; i<1000; i++) {
+			// IANA suggests using ports in the range 49152-65535 for things like this
+			result->port = 49152+(rand()%(65535-49152));
+			SDLNet_Write16(result->port, &addr.port);
+			result->sock = SDLNet_TCP_Open(&addr);
+			if(result->sock) {
+				return result;
+			} else {
+				flib_log_i("Unable to listen on port %u: %s", result->port, SDLNet_GetError());
+			}
+		}
+		flib_log_e("Unable to listen on a random unused port.");
+		free(result);
+		return NULL;
+	}
+}
+
+uint16_t flib_acceptor_listenport(flib_acceptor acceptor) {
+	return acceptor->port;
+}
+
+void flib_acceptor_close(flib_acceptor *acceptorptr) {
+	if(acceptorptr == NULL || *acceptorptr == NULL) {
+		return;
+	}
+	SDLNet_TCP_Close((*acceptorptr)->sock);
+	free(*acceptorptr);
+	*acceptorptr = NULL;
+}
+
+flib_tcpsocket flib_socket_accept(flib_acceptor acceptor, bool localOnly) {
+	flib_tcpsocket result = NULL;
+	if(!acceptor) {
+		return NULL;
+	}
+	while(result==NULL) {
+		TCPsocket sock = SDLNet_TCP_Accept(acceptor->sock);
+		if(!sock) {
+			// No incoming connections
+			return NULL;
+		}
+		if(localOnly && !connection_is_local(sock)) {
+			flib_log_i("Rejected nonlocal connection attempt from %s", flib_format_ip(get_peer_ip(sock)));
+			SDLNet_TCP_Close(sock);
+		} else {
+			result = malloc(sizeof(_flib_tcpsocket));
+			if(result==NULL) {
+				flib_log_e("Out of memory!");
+				SDLNet_TCP_Close(sock);
+				return NULL;
+			}
+			result->sock = sock;
+			result->sockset = SDLNet_AllocSocketSet(1);
+			if(result->sockset==NULL) {
+				flib_log_e("Out of memory!");
+				SDLNet_TCP_Close(sock);
+				free(result);
+				return NULL;
+			}
+			SDLNet_AddSocket(result->sockset, (SDLNet_GenericSocket)result->sock);
+		}
+	}
+	return result;
+}
+
+void flib_socket_close(flib_tcpsocket *sockptr) {
+	if(sockptr==NULL || *sockptr == NULL) {
+		return;
+	}
+	flib_tcpsocket sock = *sockptr;
+	SDLNet_DelSocket(sock->sockset, (SDLNet_GenericSocket)sock->sock);
+	SDLNet_TCP_Close(sock->sock);
+	SDLNet_FreeSocketSet(sock->sockset);
+	free(sock);
+	*sockptr = NULL;
+}
+
+int flib_socket_nbrecv(flib_tcpsocket sock, void *data, int maxlen) {
+	if(!sock) {
+		flib_log_e("Attempt to receive on a NULL socket.");
+		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, void *data, int len) {
+	return SDLNet_TCP_Send(sock->sock, data, len);
+}