Added pending responses for each client

groundStation/src/backend/backend.c

@@ -57,6 +57,10 @@ static int new_client(int fd);
 static ssize_t get_client_index(int fd);
 /* Returns pointer to client buffer, or -1 */
 static char * get_client_buffer(int fd);
+/* Return pointer to client pending responses, or -1*/ 
+static int * get_client_pend_responses(int fd);
+/* Return positive integer if successful, -1 otherwise */
+static int clientAddPendResponses(int fd, unsigned char *packet);
 /* Returns -1 on error */
 static int remove_client(int fd);
 /* Receive data from client */
@@ -86,8 +90,10 @@ const char *logHeader = "";//"#\n#\tDefault log header\n#\tEverything after '#'`
 
 #define MAX_CLIENTS 32
 #define CLIENT_BUFFER_SIZE 1024
+#define CLIENT_MAX_PENDING_RESPONSES 5
 static char client_buffers[MAX_CLIENTS][CLIENT_BUFFER_SIZE];
 static int client_fds[MAX_CLIENTS];
+static int client_pending_responses[MAX_CLIENTS][CLIENT_MAX_PENDING_RESPONSES];
 fd_set rfds_master;
 int max_fd = 0;
 
@@ -156,6 +162,9 @@ int main(int argc, char **argv)
 	for (int i = 0; i < MAX_CLIENTS; i++) {
 		client_fds[i] = -1;
 		client_buffers[i][0] = '\n';
+		for(int j = 0; j < CLIENT_MAX_PENDING_RESPONSES; j++) {
+			client_pending_responses[i][j] = -1;
+		}
 	}
 
 	if (pthread_mutex_lock(&quadSocketMutex)) {
@@ -529,6 +538,27 @@ static char * get_client_buffer(int fd) {
 	}
 }
 
+static int * get_client_pend_responses(int fd) {
+	ssize_t slot = get_client_index(fd);
+	if (slot == -1) {
+		return NULL;
+	} else {
+		return client_pending_responses[slot];
+	}
+}
+
+static int clientAddPendResponses(int fd, unsigned char *packet) {
+	int *pendingResponses = get_client_pend_responses(fd);
+	int packetID = (packet[4] << 8) | (packet[3]);
+	for(int i = 0; i < CLIENT_MAX_PENDING_RESPONSES; i++) {
+		if(pendingResponses[i] == -1) {
+			pendingResponses[i] = packetID;
+			return i;
+		}
+	}
+	return -1;
+}
+
 static int remove_client(int fd) {
 	ssize_t slot = get_client_index(fd);
 	if(slot == -1)
@@ -537,6 +567,12 @@ static int remove_client(int fd) {
 	if(clientBuffer == NULL)
 		return -1;
 	clientBuffer[0] = '\0';
+	int *pendingResponses = get_client_pend_responses(fd);
+	if(pendingResponses == NULL)
+		return -1;
+	for(int i = 0; i < CLIENT_MAX_PENDING_RESPONSES; i++) {
+		pendingResponses[i] = -1;
+	}
 	client_fds[slot] = -1;
 	return 0;
 }
@@ -591,8 +627,12 @@ static void client_recv(int fd) {
 		if(formatCommand(buffer, &packet) == -1) {
 			printf("Could not recognize command '%s'\n", buffer);
 		} else {
-			int datalen = (packet[6] << 8) | (packet[5]);
-			writeQuad((char *) packet, datalen +8);
+			if(clientAddPendResponses(fd, packet) == -1) {
+				warnx("Ran out of room! Consider increasing CLIENT_MAX_PENDING_RESPONSES!");
+			} else {	
+				int datalen = (packet[6] << 8) | (packet[5]);
+				writeQuad((char *) packet, datalen +8);
+			}
 		}
 		
 		char * rest = &buffer[newline] + 1;