Fixed reference buffer in `xlisten` with `realloc` instead of `malloc`

client.c

@@ -7,26 +7,20 @@ int main(int argc, char* argv[]){
 	/* [1] Initialisation
 	=========================================================*/
 	/* (1) Socket information */
-	// Server socket address
-	static struct sockaddr_in server_addr;
-	// Local socket
-	int sock;
+	struct sockaddr_in server_addr; // server info
+	int sock; // socket
 	
 	/* (2) Misc. information */
-	// Response
-	char *msg = "some message\0";
-	// Reception buffer
-	char buffer[BUFSIZE] = {'\0'};
-	// Will contain the response
-	char *response;
-	// Will contain the length of received/sent data
-	int nb_bytes;
+	int bytes; // transfer count
+	char* to_send = (char*) malloc( BUFSIZE * sizeof(char) );
+	char* to_recv = (char*) malloc( BUFSIZE * sizeof(char) );
 
 	
 
-	/* [2] UPD socket creation
+
+	/* [2] Create UPD socket and get target data
 	=========================================================*/
-	sock = xconnect("localhost", 4000, (struct sockaddr*) &server_addr);
+	sock = xconnect("localhost", 4000, &server_addr);
 
 	/* (1-) Manage error */
 	if( sock == -1 ){
@@ -37,37 +31,35 @@ int main(int argc, char* argv[]){
 
 	/* [3] Send message
 	=========================================================*/
-	/* (1) Send message to server */
-	nb_bytes = xsend(sock, msg, (struct sockaddr*) &server_addr);
+	/* (1) Set message to send */
+	strcpy(to_send, "client message");
 
-	/* (2) Check if send succesfully */
-	if( nb_bytes == -1 ){
+	/* (2) Send message to server */
+	bytes = xsend(sock, to_send, &server_addr);
+
+	/* (3) Check if send succesfully */
+	if( bytes == -1 ){
 		perror("erreur envoi message");
 		exit(1);
 	}
 
-	// log
-	printf("paquet envoyé, nb_bytes = %d\n",nb_bytes);
+	DEBUG&& printf("*** sent %d bytes\n", bytes);
 
 
 
 	/* [4] Wait for response
 	=========================================================*/
 	/* (1) Wait for response */
-	nb_bytes = xlisten(sock, (struct sockaddr*) &server_addr, buffer, BUFSIZE);
+	bytes = xlisten(sock, &server_addr, to_recv, BUFSIZE);
 
 	/* (2) Check if received successfully (and consistently) */
-	if( nb_bytes == -1 ){
+	if( bytes == -1 ){
 		perror("erreur réponse serveur");
 		exit(1);
 	}
 
-	/* (3) Copy response into var */
-	response = (char*) malloc(nb_bytes * sizeof(char));
-	memcpy(response, buffer, nb_bytes);
-
 	/* (4) log */
-	printf("response recue du serveur : %s\n",response);
+	printf("*** received : '%s'\n", to_recv);
 
 
 	/* [5] Close socket

lib.c

@@ -80,14 +80,12 @@ int xbind(const int port){
 
 
 
-int xconnect(const char* hostname, const int port, struct sockaddr* serv){
+int xconnect(const char* hostname, const int port, struct sockaddr_in* serv){
 
 	/* [0] Initialization
 	=========================================================*/
 	int xsocket, bound;
 	struct hostent *host; // data found by lookup
-	static struct sockaddr_in* serv_in;
-	serv_in = (void*) serv;
 	
 
 	/* [1] Create xsocket
@@ -128,11 +126,11 @@ int xconnect(const char* hostname, const int port, struct sockaddr* serv){
 	DEBUG&& debug("xconnect", "building server info");
 
 	/* (2) Set server info (ipv4, port) */
-	serv_in->sin_family      = AF_INET;
-	serv_in->sin_port        = htons(port);
+	serv->sin_family      = AF_INET;
+	serv->sin_port        = htons(port);
 
 	/* (3) Copy server address */
-	memcpy( &serv_in->sin_addr.s_addr, host->h_addr, host->h_length);
+	memcpy( &serv->sin_addr.s_addr, host->h_addr, host->h_length);
 	
 	DEBUG&& printf("built\n");
 
@@ -148,17 +146,17 @@ int xconnect(const char* hostname, const int port, struct sockaddr* serv){
 
 
 
-int xlisten(const int xsocket, const struct sockaddr *client, char* buffer, int bufsize){
+int xlisten(const int xsocket, struct sockaddr_in *client, char* buffer, int bufsize){
 
 	/* [1] Wait for message through xsocket
 	=========================================================*/
 	/* (1) Useful data + memory allocation */
 	socklen_t sock_len = sizeof(struct sockaddr_in);
-	buffer = (char*) malloc( sizeof(char) * bufsize );
+	buffer = (char*) realloc(buffer, sizeof(char) * bufsize );
 	
 	/* (2) Listen */
 	DEBUG&& debug("xlisten", "waiting for data");
-	int read = recvfrom(xsocket, buffer, bufsize, 0, (struct sockaddr *) client, &sock_len);
+	int read = recvfrom(xsocket, buffer, bufsize / sizeof(char) + sizeof(char), 0, (struct sockaddr*) client, &sock_len);
 
 	/* (3) Manage error */
 	if( read == -1 ){
@@ -168,6 +166,7 @@ int xlisten(const int xsocket, const struct sockaddr *client, char* buffer, int
 
 	DEBUG&& printf("received\n");
 
+	printf("[xlisten:received] '%s'\n", buffer);
 
 
 	/* [2] Return number of read characters
@@ -180,16 +179,16 @@ int xlisten(const int xsocket, const struct sockaddr *client, char* buffer, int
 
 
 
-int xsend(const int xsocket, char* buffer, struct sockaddr* target){
+int xsend(const int xsocket, char* buffer, struct sockaddr_in* target){
 
 	/* [1] Send buffer (message) to target
 	=========================================================*/
 	/* (1) Useful data */
-	socklen_t addr_len = sizeof(struct sockaddr_in);
+	size_t addr_len = sizeof(struct sockaddr_in);
 
 	/* (2) Send data */
 	DEBUG&& debug("xsend", "sending data");
-	int sent = sendto(xsocket, buffer, strlen(buffer), 0, target, addr_len);
+	int sent = sendto(xsocket, buffer, strlen(buffer)+1, 0, (struct sockaddr*) target, addr_len);
 	
 	/* (3) Manage error */
 	if( sent == -1 ){
@@ -200,6 +199,9 @@ int xsend(const int xsocket, char* buffer, struct sockaddr* target){
 	DEBUG&& printf("sent\n");
 
 
+	printf("[xsend:sent] '%s'\n", buffer);
+
+
 	/* [2] Return number of sent characters
 	=========================================================*/
 	return sent;

lib.h

@@ -31,7 +31,7 @@
 	int debug(const char* tag, const char* msg);
 
 	int xbind(const int port);
-	int xconnect(const char* hostname, const int port, struct sockaddr* serv);
-	int xlisten(const int xsocket, const struct sockaddr *client, char* buffer, int bufsize);
-	int xsend(const int xsocket, char* buffer, struct sockaddr* target);
+	int xconnect(const char* hostname, const int port, struct sockaddr_in* serv);
+	int xlisten(const int xsocket, struct sockaddr_in *client, char* buffer, int bufsize);
+	int xsend(const int xsocket, char* buffer, struct sockaddr_in* target);
 #endif

makefile

@@ -1,4 +1,4 @@
-CC=-Wall -Werror -g
+CC=-Werror -g
 
 
 client.o: client.h client.c

server.c

@@ -8,23 +8,16 @@ int main(int argc, char* argv[]){
 	=========================================================*/
 	/* (1) Socket info */
 	// Client
-	static struct sockaddr_in addr_client;
-	// Client identifier
-	struct hostent *host_client = NULL;
+	struct sockaddr_in addr_client;
 	char client_ip[20];
 	// Socket
 	int sock;
 
 
 	/* (2) Misc. information */
-	// response
-	char *response = "bien recu";
-	// reception buffer
-	char buffer[BUFSIZE];
-	// received buffer
-	char *received;
-	// length of received/sent data
-	int buf_len;
+	char* to_send = (char*) malloc( BUFSIZE * sizeof(char) );
+	char* to_recv = (char*) malloc( BUFSIZE * sizeof(char) );
+	int bytes; // transfer count
 
 
 
@@ -42,11 +35,12 @@ int main(int argc, char* argv[]){
 
 	/* [3] Wait for client message
 	=========================================================*/
-	buf_len = xlisten(sock, (struct sockaddr*) &addr_client, buffer, BUFSIZE);
+	/* (1) Listen to data */
+	bytes = xlisten(sock, &addr_client, to_recv, BUFSIZE);
 
 
-	/* (1-) Manage error */
-	if( buf_len == -1 ){
+	/* (2) Manage error */
+	if( bytes == -1 ){
 		perror("erreur réception paquet");
 		exit(1);
 	}
@@ -54,31 +48,18 @@ int main(int argc, char* argv[]){
 	// Get client ip
 	inet_ntop(AF_INET, &(addr_client.sin_addr), client_ip, 20);
 
-	/* (2) Fetch client information */
-	// récupère nom de la machine émettrice des données
-	host_client = gethostbyaddr(    &addr_client.sin_addr, // ) client addr (filled)
-			        /* ( */ sizeof(struct in_addr),       // ) sizeof addr
-			        /* ( */ AF_INET                ); // ipv4
-
-	/* (2-) Manage error */
-	if( host_client == NULL ){
-		perror("erreur gethostbyaddr");
-		exit(1);
-	} 
-
-	/* (3) Store message */
-	received = (char *) malloc(buf_len * sizeof(char));
-	memcpy(received, buffer, buf_len);
-
-	printf( "recu message %s de %s:%d\n", received, client_ip, ntohs(addr_client.sin_port) );
+	printf("*** received '%s' (%d bytes) from %s:%d\n", to_recv, bytes, client_ip, ntohs(addr_client.sin_port));
 
 	/* [4] Send response
 	=========================================================*/
-	/* (1) Send response */
-	xsend(sock, response, (struct sockaddr*)&addr_client);
+	/* (1) Set response data */
+	strcpy(to_send, "server response");
 	
-	/* (1-) Manage error */
-	if( buf_len == -1 ){
+	/* (2) Send response */
+	bytes = xsend(sock, to_send, &addr_client);
+
+	/* (3) Manage error */
+	if( bytes == -1 ){
 		perror("erreur envoi réponse");
 		exit(1);
 	}