Started work on the frontend networking library
authorMedo <smaxein@googlemail.com>
Thu, 31 May 2012 00:35:06 +0200
changeset 7155 273ad375d64e
parent 7152 f49254ddfc67
child 7158 a0573014ff4f
Started work on the frontend networking library
frontlib/frontlib.c
frontlib/frontlib.h
frontlib/logging.c
frontlib/logging.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frontlib/frontlib.c	Thu May 31 00:35:06 2012 +0200
@@ -0,0 +1,219 @@
+#include "frontlib.h"
+#include "logging.h"
+
+#include <SDL.h>
+#include <SDL_net.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <time.h>
+
+static int flib_initflags;
+static TCPsocket ipcListenSocket;
+static int ipcPort;
+static uint8_t ipcReadBuffer[256];
+static int ipcReadBufferSize;
+
+static TCPsocket ipcConnSocket;
+static SDLNet_SocketSet ipcConnSocketSet;
+
+static TCPsocket serverConnSocket;
+static SDLNet_SocketSet serverConnSocketSet;
+
+
+#include <time.h>
+void flib_logtime() {
+    time_t timer;
+    char buffer[25];
+    struct tm* tm_info;
+
+    time(&timer);
+    tm_info = localtime(&timer);
+
+    strftime(buffer, 25, "%H:%M:%S", tm_info);
+    printf("%s", buffer);
+}
+
+int flib_init(int flags) {
+	flib_initflags = flags;
+	ipcListenSocket = NULL;
+	ipcConnSocket = NULL;
+	serverConnSocket = NULL;
+	ipcReadBufferSize = 0;
+
+	if(!(flib_initflags | FRONTLIB_SDL_ALREADY_INITIALIZED)) {
+		if(SDL_Init(0)==-1) {
+		    flib_log_e("Error in SDL_Init: %s\n", SDL_GetError());
+		    return -1;
+		}
+	}
+
+	if(SDLNet_Init()==-1) {
+		flib_log_e("Error in SDLNet_Init: %s\n", SDLNet_GetError());
+		if(!(flib_initflags | FRONTLIB_SDL_ALREADY_INITIALIZED)) {
+			SDL_Quit();
+		}
+		return -1;
+	}
+
+	ipcConnSocketSet = SDLNet_AllocSocketSet(1);
+	serverConnSocketSet = SDLNet_AllocSocketSet(1);
+	return 0;
+}
+
+/**
+ * Free resources associated with the library. Call this function once
+ * the library is no longer needed. You can re-initialize the library by calling
+ * flib_init again.
+ */
+void flib_quit() {
+	// TODO: Send a "quit" message first?
+	SDLNet_FreeSocketSet(ipcConnSocketSet);
+	SDLNet_FreeSocketSet(serverConnSocketSet);
+
+	if(ipcListenSocket) {
+		SDLNet_TCP_Close(ipcListenSocket);
+		ipcListenSocket = NULL;
+	}
+	if(ipcConnSocket) {
+		SDLNet_TCP_Close(ipcConnSocket);
+		ipcConnSocket = NULL;
+	}
+	if(serverConnSocket) {
+		SDLNet_TCP_Close(serverConnSocket);
+		serverConnSocket = NULL;
+	}
+
+	SDLNet_Quit();
+	if(!(flib_initflags | FRONTLIB_SDL_ALREADY_INITIALIZED)) {
+		SDL_Quit();
+	}
+}
+
+/**
+ * Start listening for a connection from the engine, if we are not listening already.
+ * Returns the port we are listening on, which needs to be passed to the engine,
+ * or -1 if there is an error.
+ *
+ * We stop listening once a connection has been established, so if you want to start
+ * the engine again and talk to it you need to call this function again after the old
+ * connection is closed.
+ */
+int flib_ipc_listen() {
+	if(ipcListenSocket) {
+		return ipcPort;
+	}
+	IPaddress addr;
+	addr.host = INADDR_ANY;
+
+	/* 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
+		ipcPort = 49152+(rand()%(65535-49152));
+		SDLNet_Write16(ipcPort, &addr.port);
+		flib_log_i("Attempting to listen on port %i...\n", ipcPort);
+		ipcListenSocket = SDLNet_TCP_Open(&addr);
+		if(!ipcListenSocket) {
+			flib_log_w("Unable to listen on port %i: %s\n", ipcPort, SDLNet_GetError());
+		} else {
+			flib_log_i("ok.\n");
+			return ipcPort;
+		}
+	}
+	flib_log_e("Unable to find a usable IPC port.");
+	return -1;
+}
+
+void flib_accept_ipc() {
+	if(!ipcListenSocket) {
+		flib_log_e("Attempt to accept IPC connection while not listening.");
+		return;
+	}
+	do {
+		TCPsocket sock = SDLNet_TCP_Accept(ipcListenSocket);
+		if(!sock) {
+			// No incoming connections
+			return;
+		}
+		// Check if it is a local connection
+		IPaddress *addr = SDLNet_TCP_GetPeerAddress(sock);
+		uint32_t numip = SDLNet_Read32(&addr->host);
+		if(numip != (uint32_t)((127UL<<24)+1)) { // 127.0.0.1
+			flib_log_w("Rejected IPC connection attempt from %s\n", flib_format_ip(numip));
+		} else {
+			ipcConnSocket = sock;
+			SDLNet_AddSocket(ipcConnSocketSet, (SDLNet_GenericSocket)ipcConnSocket);
+			SDLNet_TCP_Close(ipcListenSocket);
+			ipcListenSocket = NULL;
+		}
+	} while(!ipcConnSocket);
+	return;
+}
+
+/**
+ * Receive a single message and copy it into the data buffer.
+ * Returns the length of the received message, -1 when nothing is received.
+ */
+int flib_engine_read_message(void *data) {
+	if(!ipcConnSocket && ipcListenSocket) {
+		flib_accept_ipc();
+	}
+
+	if(ipcConnSocket && SDLNet_CheckSockets(ipcConnSocketSet, 0)>0) {
+		int size = SDLNet_TCP_Recv(ipcConnSocket, ipcReadBuffer+ipcReadBufferSize, sizeof(ipcReadBuffer)-ipcReadBufferSize);
+		if(size>0) {
+			ipcReadBufferSize += size;
+		} else {
+			SDLNet_DelSocket(ipcConnSocketSet, (SDLNet_GenericSocket)ipcConnSocket);
+			SDLNet_TCP_Close(ipcConnSocket);
+			ipcConnSocket = NULL;
+			// TODO trigger "IPC disconnect" event, possibly delayed until after the messages are processed
+		}
+	}
+
+	int msgsize = ipcReadBuffer[0];
+	if(ipcReadBufferSize > msgsize) {
+		memcpy(data, ipcReadBuffer+1, msgsize);
+		memmove(ipcReadBuffer, ipcReadBuffer+msgsize+1, ipcReadBufferSize-(msgsize+1));
+		ipcReadBufferSize -= (msgsize+1);
+		return msgsize;
+	} else if(!ipcConnSocket && ipcReadBufferSize>0) {
+		flib_log_w("Last message from engine data stream is incomplete (received %u of %u bytes)", ipcReadBufferSize-1, msgsize);
+		ipcReadBufferSize = 0;
+		return -1;
+	} else {
+		return -1;
+	}
+}
+
+void flib_engine_write_message(void *data, size_t len) {
+	uint8_t sendbuf[256];
+	if(len>255) {
+		flib_log_e("Attempt to send too much data to the engine in a single message.");
+		return;
+	}
+	sendbuf[0] = len;
+	memcpy(sendbuf+1, data, len);
+	SDLNet_TCP_Send(ipcConnSocket, sendbuf, len+1);
+}
+
+int main(int argc, char *argv[]) {
+	flib_init(0);
+	int port = flib_ipc_listen();
+	printf("%i", port);
+	fflush(stdout);
+	char data[256];
+	while(ipcListenSocket||ipcConnSocket) {
+		int size = flib_engine_read_message(data);
+		if(size>0) {
+			if(data[0]=='?') {
+				flib_engine_write_message("!", 1);
+			}
+		}
+	}
+	return 0;
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frontlib/frontlib.h	Thu May 31 00:35:06 2012 +0200
@@ -0,0 +1,37 @@
+/*
+ * Public header file for the hedgewars frontent networking library.
+ *
+ * This is the only header you should need to include from frontend code.
+ */
+
+#ifndef FRONTLIB_H_
+#define FRONTLIB_H_
+
+#define FRONTLIB_SDL_ALREADY_INITIALIZED 1
+
+/**
+ * Call this function before anything else in this library.
+ *
+ * If the calling program uses SDL, it needs to call SDL_Init before initializing
+ * this library and then pass FRONTLIB_SDL_ALREADY_INITIALIZED as flag to this function.
+ *
+ * Otherwise, pass 0 to let this library handle SDL_Init an SDL_Quit itself.
+ *
+ * Returns 0 on success, -1 on error.
+ */
+int flib_init(int flags);
+
+/**
+ * Free resources associated with the library. Call this function once
+ * the library is no longer needed. You can re-initialize the library by calling
+ * flib_init again.
+ */
+void flib_quit();
+
+/**
+ * Start listening for a connection from the engine.
+ * Returns the port we are listening on, which needs to be passed to the engine.
+ */
+int flib_ipc_listen();
+
+#endif /* FRONTLIB_H_ */
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frontlib/logging.c	Thu May 31 00:35:06 2012 +0200
@@ -0,0 +1,7 @@
+#include "logging.h"
+
+char* flib_format_ip(uint32_t numip) {
+	static char ip[16];
+	snprintf(ip, 16, "%u.%u.%u.%u", numip>>24, (numip>>16)&0xff, (numip>>8)&0xff, numip&0xff);
+	return ip;
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frontlib/logging.h	Thu May 31 00:35:06 2012 +0200
@@ -0,0 +1,20 @@
+/*
+ * frontlib_internals.h
+ *
+ *  Created on: 30.05.2012
+ *      Author: simmax
+ */
+
+#ifndef LOGGING_H_
+#define LOGGING_H_
+
+#include<stdio.h>
+#include<stdint.h>
+
+char* flib_format_ip(uint32_t numip);
+
+#define flib_log_e(...) fprintf (stderr, __VA_ARGS__)
+#define flib_log_w(...) printf(__VA_ARGS__)
+#define flib_log_i(...) printf(__VA_ARGS__)
+
+#endif /* LOGGING_H_ */