Init message creation mechanism, Bug fixes

lib/circ_buff.c

@@ -40,140 +40,6 @@ unit_static void retreat_pointer(cbuf_handle_t cbuf) {
 	cbuf->tail = (cbuf->tail + 1) % cbuf->max;
 }
 
-// Compares the buffers cbuf1 and cbuf2. Elements present on cbuf1 that do not
-// exist on cbuf2 are added to the array add2, elements present on cbuf2 that do
-// not exist on cbuf1 are added to the array add1.
-// Both buffers must be ordered on the same way!
-unit_static void diff_bufs(cbuf_handle_t cbuf1, cbuf_handle_t cbuf2,
-	char ***add1, char ***add2) {
-	assert(cbuf1 && cbuf2 &&
-		(circ_buf_element_size(cbuf1) == circ_buf_element_size(cbuf2)) &&
-		(circ_buf_capacity(cbuf1) == circ_buf_capacity(cbuf2)));
-
-	// Initializes the diff arrays
-	(*add1) = (char **) malloc(circ_buf_capacity(cbuf2) * sizeof(char *));
-	(*add2) = (char **) malloc(circ_buf_capacity(cbuf1) * sizeof(char *));
-
-	char *curr_str1 = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-	char *curr_str2 = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-	/*uint8_t diff_array_index = 0;
-	for (uint8_t i = 0; i < circ_buf_size(cbuf1); ++i) {
-		// Reads current element of cbuf1
-		circ_buf_read(cbuf1, i, curr_str1);
-		bool element_exists = false;
-
-		for (uint8_t j = 0; j < circ_buf_size(cbuf2); ++j) {
-			circ_buf_read(cbuf2, j, curr_str2);
-			// Checks against cbuf2 elements
-			if (!strcmp(curr_str2, curr_str1)) {
-				element_exists = true;
-				break;
-			}
-		}
-
-		if (!element_exists) {
-			(*add2)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-			strcpy((*add2)[diff_array_index], curr_str1);
-			++diff_array_index;
-		}
-	}
-
-	(*add1)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-	strcpy((*add1)[diff_array_index], EOB);
-
-	diff_array_index = 0;
-	for (uint8_t i = 0; i < circ_buf_size(cbuf2); ++i) {
-		// Reads current element of cbuf2
-		circ_buf_read(cbuf2, i, curr_str2);
-		bool element_exists = false;
-
-		for (uint8_t j = 0; j < circ_buf_size(cbuf1); ++j) {
-			circ_buf_read(cbuf1, j, curr_str1);
-			// Checks against cbuf1 elements
-			if (!strcmp(curr_str1, curr_str2)) {
-				element_exists = true;
-				break;
-			}
-		}
-
-		if (!element_exists) {
-			(*add1)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-			strcpy((*add1)[diff_array_index], curr_str2);
-			++diff_array_index;
-		}
-	}
-
-	(*add2)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-	strcpy((*add2)[diff_array_index], EOB);*/
-
-
-
-	uint8_t cbuf1_idx = 0, cbuf2_idx = 0, add1_arr_idx = 0, add2_arr_idx = 0;
-	while ((cbuf1_idx < circ_buf_size(cbuf1)) &&
-		(cbuf2_idx < circ_buf_size(cbuf2))) {
-		circ_buf_read(cbuf1, cbuf1_idx, curr_str1);
-		circ_buf_read(cbuf2, cbuf2_idx, curr_str2);
-
-		int strcmp_res = strcmp(curr_str1, curr_str2);
-		if (!strcmp_res) {
-			++cbuf1_idx;
-			++cbuf2_idx;
-		} else { // TODO: change the inner comparisons (strtok etc)
-			if (strcmp_res < 0) {
-				(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-				strcpy((*add2)[add2_arr_idx], curr_str1);
-				++add2_arr_idx;
-				++cbuf1_idx;
-			}
-			else if (strcmp_res > 0) {
-				(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-				strcpy((*add1)[add1_arr_idx], curr_str2);
-				++add1_arr_idx;
-				++cbuf2_idx;
-			}
-		}
-	}
-
-	while (cbuf1_idx < circ_buf_size(cbuf1)) {
-		(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-		circ_buf_read(cbuf1, cbuf1_idx, curr_str1);
-		strcpy((*add2)[add2_arr_idx], curr_str1);
-		++add2_arr_idx;
-		++cbuf1_idx;
-	}
-
-	while (cbuf2_idx < circ_buf_size(cbuf2)) {
-		(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-		circ_buf_read(cbuf2, cbuf2_idx, curr_str2);
-		strcpy((*add1)[add1_arr_idx], curr_str2);
-		++add1_arr_idx;
-		++cbuf2_idx;
-	}
-
-	(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
-	strcpy((*add1)[add1_arr_idx], EOB);
-
-	(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
-	strcpy((*add2)[add2_arr_idx], EOB);
-
-	free(curr_str1);
-	free(curr_str2);
-
-	/*uint8_t i = 0;
-	printf("add1:\n");
-	while (strcmp((*add1)[i], EOB)) {
-		printf("%s\n", (*add1)[i]);
-		++i;
-	}
-
-	i = 0;
-	printf("add2:\n");
-	while (strcmp((*add2)[i], EOB)) {
-		printf("%s\n", (*add2)[i]);
-		++i;
-	}*/
-}
-
 // APIs
 
 cbuf_handle_t circ_buf_init(char **buffer, size_t size, size_t element_size) {
@@ -303,6 +169,136 @@ int circ_buf_read(cbuf_handle_t cbuf, size_t position, char *data) {
 	return r;
 }
 
+void diff_bufs(cbuf_handle_t cbuf1, cbuf_handle_t cbuf2,
+	char ***add1, char ***add2) {
+	assert(cbuf1 && cbuf2 &&
+		(circ_buf_element_size(cbuf1) == circ_buf_element_size(cbuf2)) &&
+		(circ_buf_capacity(cbuf1) == circ_buf_capacity(cbuf2)));
+
+	// Initializes the diff arrays
+	(*add1) = (char **) malloc(circ_buf_capacity(cbuf2) * sizeof(char *));
+	(*add2) = (char **) malloc(circ_buf_capacity(cbuf1) * sizeof(char *));
+
+	char *curr_str1 = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+	char *curr_str2 = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+	/*uint8_t diff_array_index = 0;
+	for (uint8_t i = 0; i < circ_buf_size(cbuf1); ++i) {
+		// Reads current element of cbuf1
+		circ_buf_read(cbuf1, i, curr_str1);
+		bool element_exists = false;
+
+		for (uint8_t j = 0; j < circ_buf_size(cbuf2); ++j) {
+			circ_buf_read(cbuf2, j, curr_str2);
+			// Checks against cbuf2 elements
+			if (!strcmp(curr_str2, curr_str1)) {
+				element_exists = true;
+				break;
+			}
+		}
+
+		if (!element_exists) {
+			(*add2)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+			strcpy((*add2)[diff_array_index], curr_str1);
+			++diff_array_index;
+		}
+	}
+
+	(*add1)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+	strcpy((*add1)[diff_array_index], EOB);
+
+	diff_array_index = 0;
+	for (uint8_t i = 0; i < circ_buf_size(cbuf2); ++i) {
+		// Reads current element of cbuf2
+		circ_buf_read(cbuf2, i, curr_str2);
+		bool element_exists = false;
+
+		for (uint8_t j = 0; j < circ_buf_size(cbuf1); ++j) {
+			circ_buf_read(cbuf1, j, curr_str1);
+			// Checks against cbuf1 elements
+			if (!strcmp(curr_str1, curr_str2)) {
+				element_exists = true;
+				break;
+			}
+		}
+
+		if (!element_exists) {
+			(*add1)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+			strcpy((*add1)[diff_array_index], curr_str2);
+			++diff_array_index;
+		}
+	}
+
+	(*add2)[diff_array_index] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+	strcpy((*add2)[diff_array_index], EOB);*/
+
+
+
+	uint8_t cbuf1_idx = 0, cbuf2_idx = 0, add1_arr_idx = 0, add2_arr_idx = 0;
+	while ((cbuf1_idx < circ_buf_size(cbuf1)) &&
+		(cbuf2_idx < circ_buf_size(cbuf2))) {
+		circ_buf_read(cbuf1, cbuf1_idx, curr_str1);
+		circ_buf_read(cbuf2, cbuf2_idx, curr_str2);
+
+		int strcmp_res = strcmp(curr_str1, curr_str2);
+		if (!strcmp_res) {
+			++cbuf1_idx;
+			++cbuf2_idx;
+		} else { // TODO: change the inner comparisons (strtok etc)
+			if (strcmp_res < 0) {
+				(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+				strcpy((*add2)[add2_arr_idx], curr_str1);
+				++add2_arr_idx;
+				++cbuf1_idx;
+			}
+			else if (strcmp_res > 0) {
+				(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+				strcpy((*add1)[add1_arr_idx], curr_str2);
+				++add1_arr_idx;
+				++cbuf2_idx;
+			}
+		}
+	}
+
+	while (cbuf1_idx < circ_buf_size(cbuf1)) {
+		(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+		circ_buf_read(cbuf1, cbuf1_idx, curr_str1);
+		strcpy((*add2)[add2_arr_idx], curr_str1);
+		++add2_arr_idx;
+		++cbuf1_idx;
+	}
+
+	while (cbuf2_idx < circ_buf_size(cbuf2)) {
+		(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+		circ_buf_read(cbuf2, cbuf2_idx, curr_str2);
+		strcpy((*add1)[add1_arr_idx], curr_str2);
+		++add1_arr_idx;
+		++cbuf2_idx;
+	}
+
+	(*add1)[add1_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf1) * sizeof(char));
+	strcpy((*add1)[add1_arr_idx], EOB);
+
+	(*add2)[add2_arr_idx] = (char*) malloc(circ_buf_element_size(cbuf2) * sizeof(char));
+	strcpy((*add2)[add2_arr_idx], EOB);
+
+	free(curr_str1);
+	free(curr_str2);
+
+	/*uint8_t i = 0;
+	printf("add1:\n");
+	while (strcmp((*add1)[i], EOB)) {
+		printf("%s\n", (*add1)[i]);
+		++i;
+	}
+
+	i = 0;
+	printf("add2:\n");
+	while (strcmp((*add2)[i], EOB)) {
+		printf("%s\n", (*add2)[i]);
+		++i;
+	}*/
+}
+
 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";

lib/circ_buff.h

@@ -20,7 +20,6 @@ typedef circ_buf_t *cbuf_handle_t;
 #define unit_static
 unit_static void advance_pointer(cbuf_handle_t cbuf);
 unit_static void retreat_pointer(cbuf_handle_t cbuf);
-unit_static void diff_bufs(cbuf_handle_t cbuf1, cbuf_handle_t cbuf2, char ***add1, char ***add2);
 #else
 #define unit_static static
 #endif
@@ -50,6 +49,13 @@ int circ_buf_get(cbuf_handle_t cbuf, char *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, char *data);
 
+// Compares the buffers cbuf1 and cbuf2. Elements present on cbuf1 that do not
+// exist on cbuf2 are added to the array add2, elements present on cbuf2 that do
+// not exist on cbuf1 are added to the array add1.
+// Both buffers must be ordered on the same way!
+void diff_bufs(cbuf_handle_t cbuf1, cbuf_handle_t cbuf2,
+	char ***add1, char ***add2);
+
 // Serializes the whole buffer to a single string
 int circ_buf_serialize(cbuf_handle_t cbuf, char **serialized);
 

lib/helpers.c

@@ -1,5 +1,86 @@
 #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);
+}
+
+int extract_id_from_ip(const char *ip) {
+	const char separator[2] = ".";
+	int id = 0;
+	char *rest, *token, *ip_cp;
+
+	ip_cp = malloc(strlen(ip) * sizeof(char));
+	strcpy(ip_cp, ip);
+
+	rest = ip_cp;
+	token = strtok_r(rest, separator, &rest);
+	if (!token || atoi(token) != 10) {
+		return -1;
+	}
+
+	token = strtok_r(rest, separator, &rest);
+	if (!token || atoi(token) != 0) {
+		return -1;
+	}
+
+	token = strtok_r(rest, separator, &rest);
+	if (!token) {
+		return -1;
+	}
+	id = atoi(token) * 100;
+
+	token = strtok_r(rest, separator, &rest);
+	if (!token) {
+		return -1;
+	}
+	id += atoi(token);
+
+	return id;
+}
+
 void set_timer_and_handler(void (*handler)(int), long int timer_interval) {
 	struct itimerval interval_timer;
 	struct sigaction signal_action;
@@ -67,7 +148,7 @@ void search_for_neighbors(node_handle_t **neighbors, uint16_t *num_neighbors, ui
 	int count = 0;
 	while (1 == fscanf(arpCache, ARP_LINE_FORMAT, ipAddr)) {
 		++count;
-		if (count > 1){
+		if (count > 1) {
 			char **r_neighbors_ips = realloc(neighbors_ips, count * sizeof(char *));
 			if (!r_neighbors_ips) {
 				free(r_neighbors_ips);
@@ -132,6 +213,20 @@ void search_for_neighbors(node_handle_t **neighbors, uint16_t *num_neighbors, ui
 	fclose(arpCache);
 }
 
+void create_message(node_handle_t *neighbors, char *new_message, int own_id,
+	uint8_t num_neighbors, uint16_t max_message_length) {
+	node_handle_t random_node = neighbors[rand() % (num_neighbors)];
+
+	int peer_id = extract_id_from_ip(inet_ntoa((node_get_addr(random_node)).sin_addr));
+	if (peer_id < 0) {
+		perror("Couldn't extract own 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!");
+}
+
 bool check_node_alive(const char *ipv4) {
 	char command[64];
 
@@ -253,5 +348,6 @@ void init_sockaddr(struct sockaddr_in *peer_name, const char *ipv4, uint16_t por
 		fprintf(stderr, "Unknown host %s.\n", ipv4);
 		exit(EXIT_FAILURE);
 	}
+
 	peer_name->sin_addr = *(struct in_addr *) hostinfo->h_addr_list[0];
 }

lib/helpers.h

@@ -1,6 +1,8 @@
 #ifndef HELPERS_H_
 #define HELPERS_H_
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <errno.h>
 #include <stdlib.h>
@@ -11,6 +13,8 @@
 #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>
@@ -31,12 +35,19 @@
 // Format for fscanf() to read the 1st field of ARP
 #define ARP_LINE_FORMAT "%" xstr(ARP_STRING_LEN) "s %*s %*s %*s %*s %*s"
 
+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 enable_echo_broadcast(void);
 
 void search_for_neighbors(node_handle_t **neighbors, uint16_t *num_neighbors, uint16_t port);
 
+void create_message(node_handle_t *neighbors, char *new_message, int own_id,
+	uint8_t num_neighbors, uint16_t max_message_length);
+
 bool check_node_alive(const char *ipv4);
 
 int create_socket_and_listen(uint16_t port, uint8_t backlog_size);

src/zaqar.c

@@ -5,12 +5,18 @@
 volatile sig_atomic_t sigalrm_flag = false;
 
 int main(void) {
-	int in_sock;
+	int in_sock, own_id;
 	fd_set active_fd_set, read_fd_set;
 	struct sockaddr_in peer_name;
 	node_handle_t *neighbors;
 	uint16_t num_neighbors = 0;
 
+	own_id = get_own_id();
+	if (own_id < 0) {
+		perror("Couldn't extract own ID.");
+		exit(EXIT_FAILURE);
+	}
+
 	// Enables echo broadcast pings
 	enable_echo_broadcast();
 
@@ -32,12 +38,14 @@ int main(void) {
 	while (1) {
 		if (sigalrm_flag) {
 			// It's time to send a message!
+			char new_message[MAX_MESSAGE_LENGTH];
 
 			search_for_neighbors(&neighbors, &num_neighbors, PORT);
+			create_message(neighbors, new_message, own_id, num_neighbors, MAX_MESSAGE_LENGTH);
 
 			for (uint8_t i = 0; i < num_neighbors; ++i) {
 				if (node_get_status(neighbors[i]) == NODE_PRESENT) {
-					send_message(node_get_addr(neighbors[i]), MESSAGE);
+					send_message(node_get_addr(neighbors[i]), new_message);
 				}
 			}
 
@@ -66,7 +74,7 @@ int main(void) {
 					accept_connection(in_sock, &peer_name, &active_fd_set);
 				} else { 
 					// Data arriving on an already-connected socket
-					if (read_from_peer(i, MAXLINE) < 0) {
+					if (read_from_peer(i, MAX_MESSAGE_LENGTH) < 0) {
 						close(i);
 						FD_CLR(i, &active_fd_set);
 					}

src/zaqar.h

@@ -20,7 +20,7 @@
 
 #define TIMER_INTERVAL 10
 #define PORT 5000
-#define MAXLINE 1024
+#define MAX_MESSAGE_LENGTH 277
 #define BACKLOG_SIZE 2
 
 void handle_alarm(int sig);