Rewrite wip

Makefile

@@ -1,17 +1,6 @@
-ifeq ($(OS),Windows_NT)
+CLEANUP = rm -f
-	ifeq ($(shell uname -s),) # not in a bash-like shell
+MKDIR = mkdir -p
-		CLEANUP = del /F /Q
+TARGET_EXTENSION=out
-		MKDIR = mkdir
-	else # in a bash-like shell, like msys
-		CLEANUP = rm -f
-		MKDIR = mkdir -p
-	endif
-		TARGET_EXTENSION=.exe
-else
-	CLEANUP = rm -f
-	MKDIR = mkdir -p
-	TARGET_EXTENSION=out
-endif
 
 .PHONY: cleandep
 .PHONY: clean
@@ -29,7 +18,8 @@ CROSSLINK = arm-linux-gnueabihf-gcc
 
 DEPEND = gcc -MM -MG -MF
 
-CROSSFLAGS = -I. -I$(PATHS) -I$(PATHL) -D_POSIX_C_SOURCE
+CROSSFLAGS = -I. -I$(PATHS) -I$(PATHL) -D_DEFAULT_SOURCE
+# CROSSFLAGS = -I. -I$(PATHS) -I$(PATHL) -D_POSIX_C_SOURCE -D_DEFAULT_SOURCE
 CROSSFLAGS += -std=c99
 CROSSFLAGS += -march=armv6
 CROSSFLAGS += -mfloat-abi=hard

lib/circ_buff.c

@@ -1,6 +1,5 @@
 #include <stdlib.h>
 #include <stdint.h>
-#include <stddef.h>
 #include <assert.h>
 
 #include <stdio.h>
@@ -94,7 +93,7 @@ size_t circ_buf_capacity(cbuf_handle_t cbuf) {
 void circ_buf_put(cbuf_handle_t cbuf, const message_handle_t *data) {
 	assert(cbuf && cbuf->buffer);
 
-	// TODO: sort and check if new data actually older!!
+	message_free(cbuf->buffer[cbuf->head]);
 	cbuf->buffer[cbuf->head] = *data;
 
 	advance_pointer(cbuf);
@@ -115,7 +114,7 @@ int circ_buf_get(cbuf_handle_t cbuf, message_handle_t *data) {
 	return r;
 }
 
-int circ_buf_read(cbuf_handle_t cbuf, size_t position, message_handle_t *data) {
+int circ_buf_peek(cbuf_handle_t cbuf, size_t position, message_handle_t *data) {
 	assert(cbuf && data && cbuf->buffer && (position < circ_buf_size(cbuf)));
 
 	int r = -1;
@@ -140,86 +139,3 @@ bool circ_buf_full(cbuf_handle_t cbuf) {
 
 	return cbuf->full;
 }
-
-/*void circ_buf_mul_add(cbuf_handle_t cbuf, char **data, uint8_t size,
-	int (*compar)(const void *, const void *)) {
-	assert(cbuf && data && cbuf->buffer);
-
-	qsort(data, size, sizeof(char*), compar);
-
-	char *last_element = (char*) malloc(circ_buf_element_size(cbuf) * sizeof(char));
-	for (uint8_t i = 0; i < size; ++i) {
-		circ_buf_read(cbuf, 0, last_element);
-
-		if (compar(&data[i], &last_element) < 0) {
-			continue;
-		}
-
-		circ_buf_put(cbuf, data[i]);
-	}
-
-	free(last_element);
-
-	int end_buffer_size = circ_buf_size(cbuf);
-	char **temp_array = (char **) malloc(end_buffer_size * sizeof(char *));
-	for (uint8_t buff_el = 0; buff_el < end_buffer_size; ++buff_el) {
-		temp_array[buff_el] = (char *) malloc(circ_buf_element_size(cbuf) * sizeof(char));
-		circ_buf_get(cbuf, temp_array[buff_el]);
-	}
-
-	qsort(temp_array, end_buffer_size, sizeof(char*), compar);
-
-	for (uint8_t i = 0; i < end_buffer_size; ++i) {
-		circ_buf_put(cbuf, temp_array[i]);
-	}
-
-	for (uint8_t buff_el = 0; buff_el < end_buffer_size; ++buff_el) {
-		free(temp_array[buff_el]);
-	}
-	free(temp_array);
-}*/
-
-
-/*int circ_buf_serialize(cbuf_handle_t cbuf, char **serialized) {
-	char *temp = (char*) malloc(circ_buf_element_size(cbuf) * sizeof(char));
-	const char separator[2] = "\r";
-	uint8_t char_sum = circ_buf_size(cbuf) - 1;
-	uint8_t i;
-
-	for (i = 0; i < circ_buf_size(cbuf); ++i) {
-		circ_buf_read(cbuf, i, temp);
-		char_sum += strlen(temp);
-	}
-
-	(*serialized) = (char*) malloc((char_sum + 1) * sizeof(char));
-	strcpy((*serialized), "");
-
-	for (i = 0; i < circ_buf_size(cbuf) - 1; ++i) {
-		circ_buf_read(cbuf, i, temp);
-		strcat((*serialized), temp);
-		strcat((*serialized), separator);
-	}
-
-	circ_buf_read(cbuf, i, temp);
-	strcat((*serialized), temp);
-
-	free(temp);
-
-	return strlen((*serialized));
-}
-
-int circ_buf_deserialize(cbuf_handle_t cbuf, const char *serialized) {
-	char *str = calloc(strlen(serialized) + 1, sizeof(char));
-	strcpy(str, serialized);
-	const char separator[2] = "\r";
-	char *token;
-
-	token = strtok(str, separator);
-
-	while (token != NULL) {
-		circ_buf_put(cbuf, token);
-		token = strtok(NULL, separator);
-	}
-
-	return circ_buf_size(cbuf);
-}*/

lib/circ_buff.h

@@ -41,7 +41,7 @@ void circ_buf_put(cbuf_handle_t cbuf, const message_handle_t *data);
 int circ_buf_get(cbuf_handle_t cbuf, message_handle_t *data);
 
 // Reads a value from the buffer. Does NOT retrieve, size is not reduced!
-int circ_buf_read(cbuf_handle_t cbuf, size_t position, message_handle_t *data);
+int circ_buf_peek(cbuf_handle_t cbuf, size_t position, message_handle_t *data);
 
 // Checks if the buffer is empty.
 bool circ_buf_empty(cbuf_handle_t cbuf);
@@ -55,10 +55,4 @@ size_t circ_buf_capacity(cbuf_handle_t cbuf);
 // Returns the number of elements stored in the buffer.
 size_t circ_buf_size(cbuf_handle_t cbuf);
 
-// Serializes the whole buffer to a single string
-// int circ_buf_serialize(cbuf_handle_t cbuf, char **serialized);
-
-// De-serializes a string to a buffer
-// int circ_buf_deserialize(cbuf_handle_t cbuf, const char *serialized);
-
 #endif //CIRC_BUFF_H_

src/helpers.c → lib/helpers.c

@@ -1,65 +1,37 @@
-#include "helpers.h"
+#include <unistd.h>
+#include <ifaddrs.h>
+#include <arpa/inet.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <netdb.h>
+#include <time.h>
+#include <assert.h>
 
-/*
+#include "helpers.h"
- * Function based on this example:
- * http://man7.org/linux/man-pages/man3/getifaddrs.3.html#EXAMPLE
-*/
-int get_own_id(void) {
-	int id = -1;
-	struct ifaddrs *ifaddr, *ifa;
-	int family, s, n;
-	char host[NI_MAXHOST];
-
-	if (getifaddrs(&ifaddr) == -1) {
-		perror("Couldn't get network interfaces.");
-		exit(EXIT_FAILURE);
-	}
-
-	// Walks through linked list, maintaining head pointer so we can free list later
-	for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa->ifa_next, n++) {
-		if (ifa->ifa_addr == NULL) {
-			continue;
-		}
-
-		family = ifa->ifa_addr->sa_family;
-
-		// Gets the address of an AF_INET* interface address
-		if (family == AF_INET || family == AF_INET6) {
-			s = getnameinfo(ifa->ifa_addr,
-				(family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6),
-				host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
-			if (s != 0) {
-				printf("getnameinfo() failed: %s\n", gai_strerror(s));
-				exit(EXIT_FAILURE);
-			}
-
-			id = extract_id_from_ip(host);
-			if (id < 0) {
-				continue;
-			}
-
-			break;
-		}
-	}
-
-	freeifaddrs(ifaddr);
 
-	return(id);
+// Private Functions
-}
 
-char get_ip_from_sockaddr(sockaddr_in addr) {
+char *get_ip_from_sockaddr(address_t addr) {
 	// Beware: The inet_ntoa() function returns a string in a statically allocated buffer, which
 	// subsequent calls will overwrite!
 	return inet_ntoa(addr.sin_addr);
 
 	// TODO: maybe change to this instead:
-	// #define MAKE_FN_NAME(x) void  Callback_ ## x (void)
+	// #define MAKE_FN_NAME(x) void Callback_ ## x (void)
 	// #define FUNCTION_NAME(signal) MAKE_FN_NAME(signal)
 }
 
-int extract_id_from_ip(const char *ip) {
+// APIs
+
+node_id_t extract_id_from_ip(const ipv4_t ip) {
+	assert(ip);
+
 	const char separator[2] = ".";
-	int id = 0;
+	node_id_t id = 0;
 	char *rest, *token, *ip_cp;
 
 	ip_cp = malloc(strlen(ip) * sizeof(char));
@@ -68,30 +40,34 @@ int extract_id_from_ip(const char *ip) {
 	rest = ip_cp;
 	token = strtok_r(rest, separator, &rest);
 	if (!token || atoi(token) != 10) {
-		return -1;
+		return 0;
 	}
 
 	token = strtok_r(rest, separator, &rest);
 	if (!token || atoi(token) != 0) {
-		return -1;
+		return 0;
 	}
 
 	token = strtok_r(rest, separator, &rest);
 	if (!token) {
-		return -1;
+		return 0;
 	}
 	id = atoi(token) * 100;
 
 	token = strtok_r(rest, separator, &rest);
 	if (!token) {
-		return -1;
+		return 0;
 	}
 	id += atoi(token);
 
+	free(ip_cp);
+
 	return id;
 }
 
 void set_timer_and_handler(void (*handler)(int), long int wakeup_time) {
+	assert(handler);
+
 	struct itimerval timer;
 	struct sigaction signal_action;
 
@@ -116,27 +92,30 @@ void set_timer_and_handler(void (*handler)(int), long int wakeup_time) {
 	}
 }
 
-void create_message(node_handle_t *neighbors, char *new_message, int own_id,
+uint16_t create_message(char *new_message, uint16_t max_message_length, node_handle_t *neighbors,
-	uint8_t num_neighbors, uint16_t max_message_length) {
+	uint8_t num_neighbors, node_id_t own_id) {
+	assert(new_message && neighbors);
 	node_handle_t random_node = neighbors[rand() % (num_neighbors)];
 
-	int peer_id = extract_id_from_ip(get_ip_from_sockaddr(node_get_addr(random_node)));
+	node_id_t peer_id = node_get_id(random_node);
-	if (peer_id < 0) {
+	if (!peer_id) {
 		perror("Couldn't extract peer's ID.");
 		exit(EXIT_FAILURE);
 	}
 
 	snprintf(new_message, max_message_length, "%04d_%04d_%ld_%s", own_id, peer_id, time(NULL),
 		"It's amazing... It's fantastic!");
+
+	return strlen(new_message);
 }
 
 /*
  * Function based on this example:
  * https://www.gnu.org/software/libc/manual/html_node/Inet-Example.html#Inet-Example
 */
-int create_socket_and_listen(uint16_t port, uint8_t backlog_size) {
+int create_socket_and_listen(port_t port, uint8_t backlog_size) {
 	int in_sock;
-	struct sockaddr_in own_name;
+	address_t own_name;
 
 	// Creates the socket
 	in_sock = socket(PF_INET, SOCK_STREAM, 0);
@@ -164,10 +143,11 @@ int create_socket_and_listen(uint16_t port, uint8_t backlog_size) {
 	return in_sock;
 }
 
-// TODO: change soccaddr_in to node
+void send_message(node_handle_t peer, message_handle_t message) {
-// TODO: change message to struct
+	assert(peer && message);
-void send_message(struct sockaddr_in peer_name, const char *message) {
+
 	int out_sock;
+	address_t peer_address = node_get_addr(peer);
 
 	// Creates the socket
 	out_sock = socket(PF_INET, SOCK_STREAM, 0);
@@ -177,124 +157,179 @@ void send_message(struct sockaddr_in peer_name, const char *message) {
 	}
 
 	// Connects to the peer
-	if (connect(out_sock, (struct sockaddr *) &peer_name, sizeof(peer_name))) {
+	if (connect(out_sock, (struct sockaddr *) &(peer_address), sizeof(node_get_addr(peer)))) {
-		printf("Couldn't connect to peer : %d.\n", get_ip_from_sockaddr(peer_name));
+		printf("Couldn't connect to peer : %s.\n", get_ip_from_sockaddr(node_get_addr(peer)));
-		// TODO: add timestamp to node
+		node_add_timestamp(peer, time(NULL), false);
 	} else {
 		// Sends data to the peer
-		write_to_peer(out_sock, message);
+		int ignored;
-		// TODO: add timestamp to node
+		write_to_peer(out_sock, message_get(message, &ignored));
-		// TODO: add sent_to to message
+		node_add_timestamp(peer, time(NULL), true);
+		message_add_sent_to(message, node_get_id(peer));
 	}
 
 	close(out_sock);
 }
 
-// TODO: add neighbors array as arg
+node_id_t accept_connection(int sock, address_t *peer_name, fd_set *active_fd_set,
-void accept_connection(int sock, struct sockaddr_in *peer_name, fd_set *active_fd_set) {
+	int *listens_on) {
+	assert(peer_name && active_fd_set && listens_on);
+
 	size_t peer_name_size = sizeof((*peer_name));
 	int comm_socket = accept(sock, (struct sockaddr *) peer_name, &peer_name_size);
 	if (comm_socket < 0) {
 		perror("Couldn't accept the connection.");
+		// TODO maye be remove this?
 		exit(EXIT_FAILURE);
 	}
 
+	*(listens_on) = comm_socket;
+
+	char *node_addr = get_ip_from_sockaddr(*peer_name);
 	fprintf(stderr, "Connected to host %s, port %hd.\n",
-		get_ip_from_sockaddr(*peer_name), ntohs((*peer_name).sin_port));
+		node_addr, ntohs((*peer_name).sin_port));
-	// TODO: add timestamp to node
+
-	// Maybe do that in zaqar (main)
 	FD_SET(comm_socket, active_fd_set);
+
+	return extract_id_from_ip(node_addr);
+}
+
+uint16_t checkAddNode(node_handle_t **neighbors, uint16_t num_neighbors ,
+	address_t peer_name, node_id_t node_id) {
+	assert(neighbors);
+
+	bool node_exists = false;
+
+	for (int i = 0; i < num_neighbors; ++i) {
+		if (node_get_id((*neighbors)[i]) == node_id) {
+			continue;
+		}
+	}
+
+	if (!node_exists) {
+		node_handle_t *r_neighbors = realloc((*neighbors),
+			(num_neighbors + 1) * sizeof(node_handle_t));
+		if (!r_neighbors) {
+			free(r_neighbors);
+			perror("Unable to reallocate memory for neighbor IP.");
+			exit(EXIT_FAILURE);
+		}
+
+		(*neighbors) = r_neighbors;
+		(*neighbors)[num_neighbors] = node_init(peer_name, node_id);
+
+		return num_neighbors + 1;
+	}
+
+	return num_neighbors;
 }
 
 void write_to_peer(int file_desc, const char *message) {
+	assert(message);
+
 	int num_bytes = write(file_desc, message, strlen(message) + 1);
 	if (num_bytes < 0) {
 		perror("Couldn't write to peer.");
+		// TODO maye be remove this?
 		exit(EXIT_FAILURE);
 	}
 }
 
-int read_from_peer(int file_des, uint16_t max_line) {
+int read_from_peer(int file_des, uint16_t max_line, cbuf_handle_t *message_buffer,
+	node_handle_t **neighbors, uint16_t num_neighbors) {
 	char buffer[max_line];
 	int num_bytes;
 
 	num_bytes = read(file_des, buffer, sizeof(buffer));
 	if (num_bytes < 0) {
 		perror("Couldn't read from peer.");
+		// TODO maye be remove this?
 		exit(EXIT_FAILURE);
-	} else if (num_bytes == 0)
+	} else if (num_bytes == 0) {
 		// End-of-file
 		return -1;
-	else {
+	} else {
 		fprintf(stderr, "Got message: `%s'\n", buffer);
-		// TODO: create new message struct
+
+		node_id_t received_from = -1;
+		for (int i = 0; i < num_neighbors; ++i) {
+			if (node_get_comm_socket((*neighbors)[i])) {
+				received_from = node_get_id((*neighbors)[i]);
+				node_set_comm_socket((*neighbors)[i], -1);
+				break;
+			}
+		}
+
+		message_handle_t new_message = message_init(buffer, num_bytes, received_from);
+		circ_buf_put(*(message_buffer), &new_message);
+
 		return 0;
 	}
 }
 
-void fread_neighbors(char *AEM_file, node_handle_t **neighbors, uint16_t *num_neighbors, uint16_t port) {
+uint16_t fread_neighbors(char *AEM_file, node_handle_t **neighbors, port_t port) {
+	assert(AEM_file && neighbors);
+	uint16_t num_neighbors = 0;
+
 	// Reads the ARP file checking for connected devices
 	FILE *aems_file = fopen(AEM_file, "r");
 	if (!aems_file) {
-		perror("Neighbors file: Failed to open file \"" AEM_file "\"");
+		perror("Neighbors file: Failed to open file containing the AEMs.");
 		exit(EXIT_FAILURE);
 	}
 
 	// Extracts IP addresses found in the file
 	char ip_addr[AEM_BUFFER_LEN];
-	char **neighbors_ips = (char **) malloc(sizeof(char *));
+	char **neighbors_ips;
-	if (!neighbors_ips) {
-		perror("Unable to allocate memory for neighbors array.");
-		exit(EXIT_FAILURE);
-	}
-
-	int (*num_neighbors) = 0;
 	while (1 == fscanf(aems_file, AEM_LINE_FORMAT, ip_addr)) {
-		++(*num_neighbors);
+		++num_neighbors;
-		if ((*num_neighbors) > 1) {
-			char **r_neighbors_ips = realloc(neighbors_ips, (*num_neighbors) * sizeof(char *));
-			if (!r_neighbors_ips) {
-				free(r_neighbors_ips);
-				perror("Unable to reallocate memory for neighbor IP.");
-				exit(EXIT_FAILURE);
-			}
 
-			neighbors_ips = r_neighbors_ips;
+		char **r_neighbors_ips = realloc(neighbors_ips, num_neighbors * sizeof(char *));
+		if (!r_neighbors_ips) {
+			free(r_neighbors_ips);
+			perror("Unable to reallocate memory for neighbor IP.");
+			exit(EXIT_FAILURE);
 		}
 
-		neighbors_ips[(*num_neighbors) - 1] = (char *) malloc(AEM_BUFFER_LEN * sizeof(char));
+		neighbors_ips = r_neighbors_ips;
-		strcpy(neighbors_ips[(*num_neighbors) - 1], ip_addr);
+
+		neighbors_ips[num_neighbors - 1] = (char *) malloc(AEM_BUFFER_LEN * sizeof(char));
+		strcpy(neighbors_ips[num_neighbors - 1], ip_addr);
 	}
 
 	// Allocates memory for the new neighbors structs
-	(*neighbors) = (node_handle_t *) malloc((*num_neighbors) * sizeof(node_handle_t));
+	(*neighbors) = (node_handle_t *) malloc(num_neighbors * sizeof(node_handle_t));
 	if (!neighbors_ips) {
 		perror("Unable to allocate memory for nodes.");
 		exit(EXIT_FAILURE);
 	}
 
 	// Creates the neighbors structs
-	for (uint8_t i = 0; i < (*num_neighbors); ++i) {
+	for (uint8_t i = 0; i < num_neighbors; ++i) {
-		struct sockaddr_in peer_name;
+		address_t peer_name;
 		init_sockaddr(&peer_name, neighbors_ips[i], port);
-		(*neighbors)[(*num_neighbors)++] = node_init(peer_name);
+		(*neighbors)[num_neighbors++] = node_init(peer_name,
+			extract_id_from_ip(get_ip_from_sockaddr(peer_name)));
 	}
 
 	fclose(aems_file);
+
+	return num_neighbors;
 }
 
 /*
  * Function based on this example:
  * https://www.gnu.org/software/libc/manual/html_node/Inet-Example.html#Inet-Example
 */
-void init_sockaddr(struct sockaddr_in *peer_name, const char *ipv4, uint16_t port) {
+void init_sockaddr(address_t *peer_name, const ipv4_t hostname, port_t port) {
+	assert(peer_name && hostname);
 	struct hostent *hostinfo;
 
 	peer_name->sin_family = AF_INET;
 	peer_name->sin_port = htons(port);
-	hostinfo = gethostbyname(ipv4);
+	hostinfo = gethostbyname(hostname);
 	if (hostinfo == NULL) {
-		fprintf(stderr, "Unknown host %s.\n", ipv4);
+		fprintf(stderr, "Unknown host %s.\n", hostname);
 		exit(EXIT_FAILURE);
 	}
 

lib/helpers.h

@@ -0,0 +1,51 @@
+#ifndef HELPERS_H_
+#define HELPERS_H_
+
+#define _GNU_SOURCE
+
+#include <stdint.h>
+
+#include "types.h"
+#include "node.h"
+#include "message.h"
+#include "circ_buff.h"
+
+// Macros to turn a numeric macro into a string literal
+#define xstr(s) str(s)
+#define str(s) #s
+
+// AEMs file related definitions
+#define AEM_ID_LEN 4
+#define AEM_BUFFER_LEN 5
+// Format for fscanf() to read the AEM numbers
+#define AEM_LINE_FORMAT "%" xstr(AEM_ID_LEN) "s\n"
+
+node_id_t extract_id_from_ip(const ipv4_t ip);
+
+void set_timer_and_handler(void (*handler)(int), long int timer_interval);
+
+uint16_t create_message(char *new_message, uint16_t max_message_length,
+	node_handle_t *neighbors, uint8_t num_neighbors, node_id_t own_id);
+
+int create_socket_and_listen(port_t port, uint8_t backlog_size);
+
+void send_message(node_handle_t peer, message_handle_t message);
+
+node_id_t accept_connection(int sock, address_t *client_name,
+	fd_set *active_fd_set, int *listens_on);
+
+uint16_t checkAddNode(node_handle_t **neighbors, uint16_t num_neighbors ,
+	address_t peer_name, node_id_t node_id);
+
+void write_to_peer(int filedes, const char *message);
+
+int read_from_peer(int file_des, uint16_t max_line,
+	cbuf_handle_t *message_buffer, node_handle_t **neighbors,
+	uint16_t num_neighbors);
+
+uint16_t fread_neighbors(char *AEM_file, node_handle_t **neighbors,
+	port_t port);
+
+void init_sockaddr(address_t *peer_name, const ipv4_t hostname, port_t port);
+
+#endif //HELPERS_H_

lib/message.c

@@ -5,45 +5,30 @@
 
 #include "message.h"
 
-/*     Private functions     */
-
 // Defines the node structure
 struct message_t {
 	char *message;
-	uint16_t received_from, *sent_to;
+	node_id_t received_from, *sent_to;
-	observer_func *observers;
+	uint16_t message_length, num_sent_to;
-	int message_length, num_sent_to, num_observers;
 };
 
-unit_static void message_state_changed(message_handle_t message_handle) {
-	assert(message_handle);
-
-	for (uint16_t i = 0; i < message_handle->num_observers; ++i) {
-		(message_handle->observers[i])();
-	}
-}
-
 /*     API     */
 
-message_handle_t message_init(const char *message, int message_length, uint16_t received_from) {
+message_handle_t message_init(const char *message, uint16_t length, node_id_t received_from) {
-	//assert(addr);
+	assert(message && length <= MAX_MESSAGE_LENGTH);
-	assert(message_length <= MAX_MESSAGE_LENGTH);
 
 	message_handle_t message_handle = malloc(sizeof(message_t));
 	assert(message_handle);
 
-	message_handle->message = malloc((message_length + 1) * sizeof(char));
+	message_handle->message = malloc((length + 1) * sizeof(char));
 	strcpy(message_handle->message, message);
-	message_handle->message_length = message_length;
+	message_handle->message_length = length;
 
 	message_handle->received_from = received_from;
 
 	message_handle->sent_to = NULL;
 	message_handle->num_sent_to = 0;
 
-	message_handle->observers = NULL;
-	message_handle->num_observers = 0;
-
 	return message_handle;
 }
 
@@ -51,82 +36,59 @@ void message_free(message_handle_t message_handle) {
 	assert(message_handle);
 
 	free(message_handle->sent_to);
-	free(message_handle->observers);
 	free(message_handle->message);
 	free(message_handle);
 }
 
-void message_add_sent_to(message_handle_t message_handle, uint16_t sent_to) {
+void message_add_sent_to(message_handle_t message_handle, node_id_t sent_to) {
 	assert(message_handle);
 
-	if (message_handle->sent_to == NULL) {
+	// Expands array by re-allocation space
-		message_handle->sent_to = (uint16_t *) malloc(sizeof(uint16_t));
+	node_id_t *r_sent_to = realloc(message_handle->sent_to, ++(message_handle->num_sent_to) * sizeof(node_id_t));
-		if (!message_handle->sent_to) {
+	if (!r_sent_to) {
-			perror("Unable to allocate memory for message receivers.");
+		free(r_sent_to);
-			exit(EXIT_FAILURE);
+		perror("Unable to reallocate memory for message receivers.");
-		}
+		exit(EXIT_FAILURE);
-		++(message_handle->num_sent_to);
-	} else {
-		uint16_t *r_sent_to = realloc(message_handle->sent_to, ++(message_handle->num_sent_to) * sizeof(uint16_t));
-		if (!r_sent_to) {
-			free(r_sent_to);
-			perror("Unable to reallocate memory for message receivers.");
-			exit(EXIT_FAILURE);
-		}
-
-		message_handle->sent_to = r_sent_to;
 	}
 
+	message_handle->sent_to = r_sent_to;
+	// ++(message_handle->num_sent_to);
+
 	message_handle->sent_to[message_handle->num_sent_to - 1] = sent_to;
-	message_state_changed(message_handle);
 }
 
-char *message_get(message_handle_t message_handle, int *message_length) {
+char *message_get(message_handle_t message_handle, int *length) {
-	assert(message_handle);
+	assert(message_handle && length);
 
-	char *message = (char *) malloc((message_handle->message_length + 1) * sizeof(char));
+	static char *message_buffer = NULL;
-	if (!message) {
+	static int message_buffer_len = 0;
-		perror("Unable to allocate memory for message return.");
+
-		exit(EXIT_FAILURE);
+	if (message_buffer_len != message_handle->message_length + 1) {
+		char *r_message_buffer = (char *) realloc(message_buffer, (message_handle->message_length + 1) * sizeof(char));
+		if (!r_message_buffer) {
+			free(r_message_buffer);
+			perror("Unable to reallocate memory for message receivers.");
+			exit(EXIT_FAILURE);
+		}
+
+		message_buffer = r_message_buffer;
+		message_buffer_len = message_handle->message_length + 1;
 	}
 
-	strcpy(message, message_handle->message);
+	strcpy(message_buffer, message_handle->message);
-	(*message_length) = message_handle->message_length;
+	(*length) = message_handle->message_length;
 
-	return message;
+	return message_buffer;
 }
 
-bool message_sent_to(message_handle_t message_handle, uint16_t node) {
+bool message_sent_to(message_handle_t message_handle, node_id_t id) {
 	assert(message_handle);
 
 	for (uint16_t i = 0; i < message_handle->num_sent_to; ++i) {
-		if (message_handle->sent_to[i] == node) {
+		if (message_handle->sent_to[i] == id) {
 			return true;
 		}
 	}
 
 	return false;
 }
-
-void message_attach_observer(message_handle_t message_handle, observer_func observer) {
-	assert(message_handle);
-
-	if (message_handle->observers == NULL) {
-		message_handle->observers = (observer_func *) malloc(sizeof(observer_func));
-		if (!message_handle->observers) {
-			perror("Unable to allocate memory for message observers.");
-			exit(EXIT_FAILURE);
-		}
-		++(message_handle->num_observers);
-	} else {
-		uint16_t *r_observers = realloc(message_handle->observers,
-			++(message_handle->num_observers) * sizeof(observer_func));
-		if (!r_observers) {
-			free(r_observers);
-			perror("Unable to reallocate memory for message observers.");
-			exit(EXIT_FAILURE);
-		}
-	}
-
-	message_handle->observers[message_handle->num_observers - 1] = observer;
-}

lib/message.h

@@ -4,6 +4,16 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include "types.h"
+
+// max_message_length =   sender_id        4   chars
+//                      + underscore       1   char
+//                      + receiver_id      4   chars
+//                      + underscore       1   char
+//                      + time-stamp       10  chars
+//                      + underscore       1   char
+//                      + message_text     256 chars (max)
+//                    =                    277 chars
 #define MAX_MESSAGE_LENGTH 277
 
 // Message structure
@@ -11,34 +21,21 @@ typedef struct message_t message_t;
 // and handle type
 typedef message_t *message_handle_t;
 
-typedef void (*observer_func)(void);
-
-#ifdef TEST //This is a test build
-// Makes private functions reachable by the tester
-#define unit_static
-// Calls all observer functions attached to this message.
-unit_static void message_state_changed(message_handle_t message_handle);
-#else
-#define unit_static static
-#endif
-
 // Initializes a message structure and returns the message handle. User must provide the length of
 // the message without the null termination character (strlen);
-message_handle_t message_init(const char *message, int message_length, uint16_t received_from);
+message_handle_t message_init(const char *message, uint16_t length, node_id_t received_from);
 
 // Frees a message structure.
 void message_free(message_handle_t message_handle);
 
 // Adds an new receiver to the message.
-void message_add_sent_to(message_handle_t message_handle, uint16_t sent_to);
+void message_add_sent_to(message_handle_t message_handle, node_id_t sent_to);
 
-// Returns the message.
+// Returns the message. This functions returns a string in a statically allocated buffer, which
+// subsequent calls will overwrite!
 char *message_get(message_handle_t message_handle, int *message_length);
 
-// Returns true if the message has been previously sent to this node, false otherwise.
+// Returns true if the message has been previously sent to this ip, false otherwise.
-bool message_sent_to(message_handle_t message_handle, uint16_t node);
+bool message_sent_to(message_handle_t message_handle, node_id_t id);
-
-// Attaches an observer function to the message.
-void message_attach_observer(message_handle_t message_handle, observer_func observer);
 
 #endif //MESSAGE_H_

lib/node.c

@@ -1,34 +1,34 @@
 #include <stdlib.h>
 #include <assert.h>
+#include <time.h>
 #include <stdio.h>
 #include <string.h>
+#include <arpa/inet.h>
 
 #include "node.h"
 
 // Defines the node structure
 struct node_t {
-	struct sockaddr_in addr;
+	address_t addr;
-	uint64_t **events;
+	node_id_t id;
-	uint64_t appearance_duration;
+	timestamp_t *events_timestamps;
-	uint8_t events_size;
+	node_status *events_status;
-	node_status _node_status;
+	uint16_t events_size;
+	int comm_socket;
 };
 
-node_handle_t node_init(struct sockaddr_in addr) {
+node_handle_t node_init(address_t addr, node_id_t id) {
-	//assert(addr);
-
 	node_handle_t node = malloc(sizeof(node_t));
 	assert(node);
 
 	node->addr = addr;
-	node->events_size = 0;
+	node->id = id;
-	node->events = (uint64_t **) malloc(2 * sizeof(uint64_t));
+	node->events_timestamps = (timestamp_t *) malloc(sizeof(timestamp_t));
-	node->events[0] = (uint64_t *) malloc(sizeof(uint64_t));
+	node->events_timestamps[0] = time(NULL);
-	node->events[1] = (uint64_t *) malloc(sizeof(uint64_t));
+	node->events_status = (node_status *) malloc(sizeof(node_status));
-	node->events[0][0] = 0;
+	node->events_status[0] = NODE_INITIALIAZED;
-	node->events[1][0] = 0;
+	node->events_size = 1;
-	node->appearance_duration = 0;
+	node->comm_socket = -1;
-	node->_node_status = NODE_INITIALIAZED;
 
 	return node;
 }
@@ -36,89 +36,67 @@ node_handle_t node_init(struct sockaddr_in addr) {
 void node_free(node_handle_t node) {
 	assert(node);
 
-	free(node->events[0]);
+	free(node->events_timestamps);
-	free(node->events[1]);
+	free(node->events_status);
-	free(node->events);
 	free(node);
 }
 
-void node_add_timestamp(node_handle_t node, time_t timestamp, bool visible) {
+void node_add_timestamp(node_handle_t node, timestamp_t timestamp, bool visible) {
 	assert(node && timestamp);
 
-	if ((visible && !node->events[1][node->events_size - 1]) ||
+	int *realloc_r = realloc(node->events_timestamps, node->events_size + 1);
-		(!visible && node->events[1][node->events_size - 1])) {
+	if (!realloc_r) {
-		return;
+		node_free(node);
+		perror("Error trying to reallocate memory for event timestamps.");
+		exit(EXIT_FAILURE);
 	}
 
-	if (visible) {
+	realloc_r = realloc(node->events_status, node->events_size + 1);
-		int *realloc_r = realloc(node->events[0], node->events_size + 1);
+	if (!realloc_r) {
-		if (!realloc_r) {
+		node_free(node);
-			node_free(node);
+		perror("Error trying to reallocate memory for event statuses.");
-			perror("Error trying to reallocate memory for event timestamps!");
+		exit(EXIT_FAILURE);
-			exit(EXIT_FAILURE);
-		}
-		realloc_r = realloc(node->events[1], node->events_size + 1);
-		if (!realloc_r) {
-			node_free(node);
-			perror("Error trying to reallocate memory for event timestamps!");
-			exit(EXIT_FAILURE);
-		}
-
-		node->events[0][node->events_size] = timestamp;
-		node->events[1][node->events_size] = 0;
-		node->_node_status = NODE_PRESENT;
-		++node->events_size;
-	} else {
-		node->events[1][node->events_size - 1] = timestamp;
-		node->_node_status = NODE_GONE;
-		node->appearance_duration += node->events[1][node->events_size - 1] -
-			node->events[0][node->events_size - 1];
 	}
+
+	node->events_timestamps[node->events_size] = timestamp;
+	node->events_status[node->events_size] = visible ? NODE_PRESENT : NODE_GONE;
+	++node->events_size;
 }
 
-struct sockaddr_in node_get_addr(node_handle_t node) {
+address_t node_get_addr(node_handle_t node) {
 	assert(node);
 
 	return node->addr;
 }
 
-enum node_status node_get_status(node_handle_t node) {
+node_id_t node_get_id(node_handle_t node) {
 	assert(node);
 
-	return node->_node_status;
+	return node->id;
 }
 
-uint8_t node_get_latest_appearance_duration(node_handle_t node) {
+node_status node_get_status(node_handle_t node) {
 	assert(node);
 
-	if (node->_node_status == NODE_INITIALIAZED) {
+	return node->events_status[node->events_size];
-		return 0;
-	} else if (node->events[1][node->events_size - 1] == 0) {
-		return (uint64_t)time(NULL) - node->events[0][node->events_size - 1];
-	} else {
-		return node->events[1][node->events_size - 1] - node->events[0][node->events_size - 1];
-	}
 }
 
-uint8_t node_get_total_appearance_duration(node_handle_t node) {
+int node_get_comm_socket(node_handle_t node) {
-	assert(node);
+	return node->comm_socket;
-
-	return node->appearance_duration;
 }
 
-uint8_t node_get_event_table(node_handle_t node, time_t ***event_table) {
+void node_set_comm_socket(node_handle_t node, int comm_socket) {
-	assert(node && event_table);
+	node->comm_socket = comm_socket;
+}
 
-	if (node->events_size < 1) {
+uint16_t node_get_events(node_handle_t node, timestamp_t **events_timestamps, node_status **events_status) {
-		return 0;
+	assert(node && events_timestamps && events_status);
-	}
 
-	(*event_table) = (time_t **) malloc(2 * sizeof(time_t *));
+	(*events_timestamps) = (timestamp_t *) malloc(node->events_size * sizeof(timestamp_t));
-	(*event_table)[0] = (time_t *) malloc(node->events_size * sizeof(time_t));
+	(*events_status) = (node_status *) malloc(node->events_size * sizeof(node_status));
-	(*event_table)[1] = (time_t *) malloc(node->events_size * sizeof(time_t));
 
-	memcpy((*event_table)[0], node->events[0], node->events_size * sizeof(time_t));
+	memcpy((*events_timestamps), node->events_timestamps, node->events_size * sizeof(timestamp_t));
-	memcpy((*event_table)[1], node->events[1], node->events_size * sizeof(time_t));
+	memcpy((*events_status), node->events_status, node->events_size * sizeof(node_status));
 
 	return node->events_size;
 }

lib/node.h

@@ -2,8 +2,9 @@
 #define NODE_H_
 
 #include <stdbool.h>
-#include <time.h>
+#include <stdint.h>
-#include <arpa/inet.h>
+
+#include "types.h"
 
 // Node structure
 typedef struct node_t node_t;
@@ -12,48 +13,33 @@ typedef node_t *node_handle_t;
 
 typedef enum node_status { NODE_INITIALIAZED, NODE_PRESENT, NODE_GONE } node_status;
 
-#ifdef TEST //This is a test build
-// Makes private functions reachable by the tester
-#define unit_static
-#else
-#define unit_static static
-#endif
-
 // Initializes a node structure and returns the node handle.
-node_handle_t node_init(struct sockaddr_in addr);
+node_handle_t node_init(address_t addr, node_id_t id);
 
 // Frees a node structure.
 void node_free(node_handle_t node);
 
-// Adds an event timestamp to the node. Either the (re)appearance or the disappearance of the node.
+// Adds an event timestamp to the node.
-void node_add_timestamp(node_handle_t node, time_t timestamp, bool visible);
+void node_add_timestamp(node_handle_t node, timestamp_t timestamp, bool visible);
 
 // Returns the address of the node
-struct sockaddr_in node_get_addr(node_handle_t node);
+address_t node_get_addr(node_handle_t node);
-
-node_status node_get_status(node_handle_t node);
 
-//uint8_t node_get_appear_count(node_handle_t node);
+// Returns the id of the node
+node_id_t node_get_id(node_handle_t node);
 
-//uint8_t node_get_disappear_count(node_handle_t node);
+// Returns the latest node status.
-
+node_status node_get_status(node_handle_t node);
-//void node_get_latest_appear(node_handle_t node, );
-
-//void node_get_latest_disappear(node_handle_t node, );
-
-// Returns the duration (in seconds) of the latest stretch of time that this node has been visible.
-uint8_t node_get_latest_appearance_duration(node_handle_t node);
 
-// Returns the total duration (in seconds) of time that this node was visible.
+// Returns the current communication socket id of the node
-uint8_t node_get_total_appearance_duration(node_handle_t node);
+int node_get_comm_socket(node_handle_t node);
 
-// Returns the event timestamps table for this node.
+// Sets the current communication socket id of the node
-uint8_t node_get_event_table(node_handle_t node, time_t ***event_table);
+void node_set_comm_socket(node_handle_t node, int comm_socket);
 
-// Serializes the whole node to a single string
+// Returns the event tables for this node.
-//int circ_buf_serialize(node_handle_t node, char **serialized);
+uint16_t node_get_events(node_handle_t node, timestamp_t **events_timestamps, node_status **events_status);
 
-// De-serializes a string to a node
+//TODO node save thingy
-//int circ_buf_deserialize(node_handle_t node, const char *serialized);
 
 #endif //NODE_H_

lib/types.h

@@ -0,0 +1,10 @@
+#ifndef CUSTOM_TYPES_H_
+#define CUSTOM_TYPES_H_
+
+typedef uint16_t node_id_t;
+typedef struct sockaddr_in address_t;
+typedef uint64_t timestamp_t;
+typedef char *ipv4_t;
+typedef uint16_t port_t;
+
+#endif //CUSTOM_TYPES_H_

src/helpers.h

@@ -1,59 +0,0 @@
-#ifndef HELPERS_H_
-#define HELPERS_H_
-
-#define _GNU_SOURCE
-
-#include <stdio.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <netdb.h>
-#include <arpa/inet.h>
-#include <sys/select.h>
-#include <ifaddrs.h>
-#include <linux/if_link.h>
-#include <sys/time.h>
-#include <signal.h>
-#include <string.h>
-#include <sys/wait.h>
-
-#include "node.h"
-
-// Macros to turn a numeric macro into a string literal
-#define xstr(s) str(s)
-#define str(s) #s
-
-// AEMs file related definitions
-#define AEM_BUFFER_LEN 5
-
-// Format for fscanf() to read the AEM numbers
-#define ARP_LINE_FORMAT "%" xstr(ARP_STRING_LEN) "s\n"
-
-
-int get_own_id(void);
-
-int extract_id_from_ip(const char *ip);
-
-void set_timer_and_handler(void (*handler)(int), long int timer_interval);
-
-void create_message(char *new_message, uint16_t max_message_length, node_handle_t *neighbors,
-	uint8_t num_neighbors,  int own_id);
-
-int create_socket_and_listen(uint16_t port, uint8_t backlog_size);
-
-void send_message(struct sockaddr_in peer_name, const char *message);
-
-void accept_connection(int sock, struct sockaddr_in *client_name, fd_set *active_fd_set);
-
-void write_to_peer(int filedes, const char *message);
-
-int read_from_peer(int file_des, uint16_t max_line);
-
-void fread_neighbors(char *AEM_file, node_handle_t **neighbors, uint16_t *num_neighbors, uint16_t port);
-
-void init_sockaddr(struct sockaddr_in *name, const char *hostname, uint16_t port);
-
-#endif //HELPERS_H_

src/zaqar.c

@@ -1,3 +1,15 @@
+#include <arpa/inet.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/select.h>
+#include <unistd.h>
+
+#include "types.h"
+#include "message.h"
+#include "circ_buff.h"
+#include "helpers.h"
 #include "zaqar.h"
 
 #define MESSAGE "You got mail!!! xo xo xo"
@@ -8,22 +20,24 @@ int main(int argc, char **argv) {
 	check_args(argc, argv);
 
 	// Socket communication variables
-	int in_sock, own_id;
+	int in_sock;
 	fd_set active_fd_set, read_fd_set;
-	struct sockaddr_in peer_name;
+	address_t peer_name;
+	node_id_t own_id = atoi(argv[1]);
 
 	// Business logic variables
 	node_handle_t *neighbors;
 	uint16_t num_neighbors = 0;
+	message_handle_t *buffer;
+	cbuf_handle_t message_buffer;
 
-	own_id = get_own_id();
+	bool exhaustive_send = false;
-	if (own_id < 0) {
+
-		perror("Couldn't extract own ID.");
+	buffer = (message_handle_t *) malloc(MESSAGE_BUFFER_SIZE * sizeof(message_handle_t));
-		exit(EXIT_FAILURE);
+	message_buffer = circ_buf_init(buffer, MESSAGE_BUFFER_SIZE);
-	}
 
 	// Reads neighbors' IPs from file
-	void fread_neighbors(argv[1], &neighbors, &num_neighbors, PORT);
+	num_neighbors = fread_neighbors(argv[1], &neighbors, PORT);
 
 	// Sets a timer and handler to produce an interrupt and send a message
 	set_timer_and_handler(handle_alarm, MIN_TIMER_VAL + rand() % (MAX_TIMER_VAL - MIN_TIMER_VAL));
@@ -40,18 +54,37 @@ int main(int argc, char **argv) {
 	while (1) {
 		if (sigalrm_flag) {
 			// It's time to send a message!
-			char new_message[MAX_MESSAGE_LENGTH];
+			char new_message_payload[MAX_MESSAGE_LENGTH];
-			create_message(new_message, MAX_MESSAGE_LENGTH, neighbors, num_neighbors, own_id);
+			uint16_t new_message_length = create_message(new_message_payload, MAX_MESSAGE_LENGTH,
+				neighbors, num_neighbors, own_id);
 
-			for (uint8_t i = 0; i < num_neighbors; ++i) {
+			message_handle_t new_message = message_init(new_message_payload, new_message_length, own_id);
-				if (node_get_status(neighbors[i]) == NODE_PRESENT) {
+			circ_buf_put(message_buffer, &new_message);
-					send_message(node_get_addr(neighbors[i]), new_message);
+
-				}
+			for (uint16_t i = 0; i < num_neighbors; ++i) {
+				send_message(neighbors[i], new_message);
 			}
 
 			// Resets timer
 			sigalrm_flag = false;
 			set_timer_and_handler(handle_alarm, MIN_TIMER_VAL + rand() % (MAX_TIMER_VAL - MIN_TIMER_VAL));
+
+			// Checks for new neighbors/unsent messages while awake
+			exhaustive_send = true;
+		}
+
+		if (exhaustive_send) {
+			for (uint16_t node_index = 0; node_index < num_neighbors; ++node_index) {
+				node_id_t current_node_id = node_get_id(neighbors[node_index]);
+
+				for (uint message_index = 0; message_index < circ_buf_size(message_buffer); ++message_index) {
+					message_handle_t current_message;
+
+					if (!circ_buf_peek(message_buffer, message_index, &current_message) &&
+						!message_sent_to(current_message, current_node_id))
+						send_message(neighbors[node_index], current_message);
+				}
+			}
 		}
 
 		// Shallow copies the readset
@@ -68,33 +101,59 @@ int main(int argc, char **argv) {
 			exit(EXIT_FAILURE);
 		}
 
-		// TODO: sent new messages to all neighbors
-		// TODO: if found new neighbor, sent all messages
-
 		// Services all the sockets with input pending
 		for (int i = 0; i < FD_SETSIZE; ++i) {
 			if (FD_ISSET(i, &read_fd_set)) {
 				if (i == in_sock) {
 					// Connection request on original socket
-					accept_connection(in_sock, &peer_name, &active_fd_set);
+					int comm_socket;
+					node_id_t peer_id = accept_connection(in_sock, &peer_name, &active_fd_set,
+						&comm_socket);
+
+					// Updates neighbors array
+					num_neighbors = checkAddNode(&neighbors, num_neighbors , peer_name, peer_id);
+					if (comm_socket >= 0) {
+						for (int i = 0; i < num_neighbors; ++i) {
+							if(node_get_id(neighbors[i]) == peer_id) {
+								node_set_comm_socket(neighbors[i], comm_socket);
+								break;
+							}
+						}
+					}
 				} else { 
 					// Data arriving on an already-connected socket
-					if (read_from_peer(i, MAX_MESSAGE_LENGTH) < 0) {
+					if (read_from_peer(i, MAX_MESSAGE_LENGTH + 1, &message_buffer, &neighbors, num_neighbors) < 0) {
 						close(i);
 						FD_CLR(i, &active_fd_set);
+
+						// Checks for new neighbors/unsent messages while awake
+						exhaustive_send = true;
 					}
 				}
 			}
 		}
 	}
 
+	//Frees memory
+	for (uint i = 0; i < circ_buf_size(message_buffer); ++i) {
+		message_handle_t current_message;
+
+		circ_buf_get(message_buffer, &current_message);
+		message_free(current_message);
+	}
+	circ_buf_free(message_buffer);
+	for (int i = 0; i < num_neighbors; ++i) {
+		node_free(neighbors[i]);
+	}
+	free(buffer);
+
 	return 0;
 }
 
 void check_args(int argc, char **argv) {
-	if (argc < 2) {
+	if (argc != 3) {
 		printf("Correct usage is:\n");
-		printf("\t%s <aems_file> \n", argv[0]);
+		printf("\t%s <node_id> <aems_file> \n", argv[0]);
 		exit(EXIT_FAILURE);
 	}
 }

src/zaqar.h

@@ -1,38 +1,11 @@
 #ifndef ZAQAR_H_
 #define ZAQAR_H_
 
-#include <stdbool.h>
-#include <stdio.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <netdb.h>
-#include <arpa/inet.h>
-#include <sys/select.h>
-
-#include <sys/signalfd.h>
-
-#include "helpers.h"
-#include "message.h"
-#include "circ_buff.h"
-
 #define MIN_TIMER_VAL 60
 #define MAX_TIMER_VAL 300
 #define PORT 5000
-// max_message_length =   sender_id        4   chars
-//                      + underscore       1   char
-//                      + receiver_id      4   chars
-//                      + underscore       1   char
-//                      + time-stamp       10  chars
-//                      + underscore       1   char
-//                      + message_text     256 chars (max)
-//                      + null_terminator  1   char
-//                    =                    278 chars
-#define MAX_MESSAGE_LENGTH 278
 #define BACKLOG_SIZE 2
+#define MESSAGE_BUFFER_SIZE 2000
 
 void check_args(int argc, char **argv);