handling new clients in a separate thread
This commit is contained in:
Igor Socec
parent
86f0bc612f
commit
604665ee05
4 changed files with 99 additions and 95 deletions
11
client.c
11
client.c
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@ -86,32 +86,31 @@ int client_write(struct client_t *client, char *databuf, int datalen) {
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/* Waits for client input in "line mode". Blocks until input arrives. */
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int client_wait_line(struct client_t *client) {
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int ret;
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fd_set read_fds;
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struct timeval tv;
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client->data[0] = '\0';
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/* loop waiting for client input */
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while (client->data[0] == '\0') {
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/* setup select() parameters */
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tv.tv_sec = 15; /* 15 second timeout */
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tv.tv_usec = 0;
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FD_ZERO(&read_fds);
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FD_SET(client->socket, &read_fds);
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/* send prompt character to client */
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client_write(client, "> ", 2);
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/* block until input arrives */
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if (select((client->socket)+1, &read_fds, NULL, NULL, NULL) == -1) return -1;
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if (select((client->socket)+1, &read_fds, NULL, NULL, &tv) <= 0) return -1;
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if (FD_ISSET(client->socket, &read_fds)) {
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/* read client input */
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ret = client_read(client);
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if (ret == -1) return -1;
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if (client_read(client) == -1) return -1;
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/* we don't want empty data so stop on \r or \n */
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if ( (client->data[0] == '\r') || (client->data[0] == '\n') ) {
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fprintf(stderr, "client data is empty\n");
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client->data[0] = '\0';
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}
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}
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}
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fprintf(stderr, "client data: %s\n", client->data);
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return 0;
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}
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63
moxerver.c
63
moxerver.c
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@ -11,7 +11,7 @@
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#define NAME "moxerver"
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#define SERVER_WAIT_TIMEOUT 5 /* seconds for select() timeout in server loop */
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#define SERVER_WAIT_TIMEOUT 2 /* seconds for select() timeout in server loop */
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/* Prints help message. */
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static void usage() {
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@ -82,15 +82,14 @@ int main(int argc, char *argv[]) {
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int fdmax;
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struct timeval tv;
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pthread_t tty_thread;
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pthread_t tty_thread, new_client_thread;
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/* zero init tty_dev */
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if (cfsetispeed(&(tty_dev.ttyset), B0) < 0 ||
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cfsetospeed(&(tty_dev.ttyset), B0) < 0) {
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fprintf(stderr, "[%s] error configuring tty device speed\n", NAME);
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return -1;
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}
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}
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/* enable catching and handling some quit signals, SIGKILL can't be caught */
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signal(SIGTERM, quit_handler);
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@ -141,6 +140,7 @@ int main(int argc, char *argv[]) {
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/* initialize */
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if (server_setup(&server, tcp_port) < 0) return -1;
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client.socket = -1;
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new_client.socket = -1;
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tty_dev.fd = -1;
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/* parse config file if any */
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@ -150,7 +150,7 @@ int main(int argc, char *argv[]) {
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return -1;
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}
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else if (!def_conf && ret) {
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fprintf(stderr, "[%s] error parsing congig file %s on line %d\n", NAME, CONFILE, ret);
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fprintf(stderr, "[%s] error parsing config file %s on line %d\n", NAME, CONFILE, ret);
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return -1;
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}
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@ -177,9 +177,25 @@ int main(int argc, char *argv[]) {
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return -1;
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}
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/* loop with timeouts waiting for client connection and data */
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/* loop with timeouts waiting for client connection requests and data */
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while (1) {
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/* check if new client is availabe for connection */
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if ( (client.socket == -1) && (new_client.socket != -1) ) {
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/* copy new client information */
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memcpy(&client, &new_client, sizeof(struct client_t));
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new_client.socket = -1;
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fprintf(stderr, "[%s] client %s connected\n", NAME, client.ip_string);
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/* ask client to provide a username before going to "character" mode */
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if (client_ask_username(&client) != 0) {
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/* close client if not able to provide a username */
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client_close(&client);
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continue;
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}
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/* put client in "character" mode */
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telnet_set_character_mode(&client);
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}
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/* setup parameters for select() */
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tv.tv_sec = SERVER_WAIT_TIMEOUT;
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tv.tv_usec = 0;
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@ -201,36 +217,11 @@ int main(int argc, char *argv[]) {
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/* check server status */
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if (FD_ISSET(server.socket, &read_fds)) {
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fprintf(stderr, "[%s] received client connection request\n", NAME);
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/* accept connection request if no client is connected */
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if (client.socket == -1) {
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ret = server_accept(&server, &client);
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if ( ret != 0) {
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/* print error but continue waiting for connection request */
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//TODO maybe we should break here to avoid endless loop, what are possible causes of this failure?
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fprintf(stderr, "[%s] problem accepting client\n", NAME);
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continue;
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}
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/* ask client to provide a username before going to "character" mode */
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client_ask_username(&client);
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/* put client in "character" mode */
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telnet_set_character_mode(&client);
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}
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/* if a client is already connected then new clients need to be handled */
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else {
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/* decide if current client needs to be dropped or new client needs to be rejected */
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ret = server_drop(&server, &client);
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if (ret < 0) {
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/* error in handling new clients, print but continue waiting for new clients */
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fprintf(stderr, "[%s] problem handling new client request\n", NAME);
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continue;
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}
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/* if current client was dropped we need to set up new client */
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if (ret > 0) {
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/* ask client to provide a username before going to "character" mode */
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client_ask_username(&client);
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/* put client in "character" mode */
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telnet_set_character_mode(&client);
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}
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/* handle new client connection request in a separate thread */
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if (pthread_create(&new_client_thread, NULL, server_new_client_thread, NULL) != 0) {
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/* print error but continue waiting for connection request */
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fprintf(stderr, "[%s] problem with handling client connection request\n", NAME);
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continue;
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}
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}
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/* check client status if connected */
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45
moxerver.h
45
moxerver.h
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@ -21,34 +21,35 @@
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/* Structures used for communication parameters. */
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struct server_t {
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int socket; /* server socket */
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struct sockaddr_in address; /* server address information */
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int socket; /* server socket */
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struct sockaddr_in address; /* server address information */
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unsigned int port; /* server port in host byte order, practical reference */
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};
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struct client_t {
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int socket; /* client socket */
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struct sockaddr_in address; /* client address information */
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char ip_string[INET_ADDRSTRLEN]; /* client IP address as a string */
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time_t last_active; /* time of client's last activity in seconds from Epoch */
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char username[USERNAME_LEN]; /* username for human identification */
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char data[DATABUF_LEN]; /* buffer for data received from client */
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int socket; /* client socket */
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struct sockaddr_in address; /* client address information */
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char ip_string[INET_ADDRSTRLEN]; /* client IP address as a string */
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time_t last_active; /* time of client's last activity in seconds from Epoch */
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char username[USERNAME_LEN]; /* username for human identification */
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char data[DATABUF_LEN]; /* buffer for data received from client */
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};
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struct tty_t {
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int fd; /* tty file descriptor */
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int fd; /* tty file descriptor */
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struct termios ttysetdef; /* default tty termios settings */
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struct termios ttyset; /* tty termios settings */
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char path[DEV_PATH]; /* tty device path */
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char data[DATABUF_LEN]; /* buffer for data received from tty */
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char path[DEV_PATH]; /* tty device path */
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char data[DATABUF_LEN]; /* buffer for data received from tty */
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};
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/* Global variables used throughout the application. */
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int debug_messages; /* if > 0 debug messages will be printed */
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struct server_t server; /* main server structure */
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struct client_t client; /* connected client structure */ //TODO working with only 1 client, this can be expanded into a list
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struct tty_t tty_dev; /* connected tty device */
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int debug_messages; /* if > 0 debug messages will be printed */
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struct server_t server; /* main server structure */
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struct client_t client; /* connected client structure */ //TODO working with only 1 client, this can be expanded into a list
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struct client_t new_client; /* client structure for new client request */
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struct tty_t tty_dev; /* connected tty device */
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/* Global functions used throughout the application. */
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@ -91,15 +92,17 @@ int server_close(struct server_t *server);
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int server_accept(struct server_t *server, struct client_t *accepted_client);
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/**
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* Asks new incoming client connection if current client needs to be dropped.
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* If current client doesn't need to be dropped then new client is rejected.
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* Thread function handling new client connections.
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* If there is no connected client then first client request is accepted.
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* If there is a connected client then new client is asked if connected client should be dropped.
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*
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* Returns:
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* - positive value if current client was dropped
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* - 0 if new client was rejected
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* - negative value if error occurred
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* Return value from this thread function is not used.
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* Function handles global client variables:
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* - client structure is reset if new client is available to connect to
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* - new_client structure stores information about the client to connect to
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*/
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int server_drop(struct server_t *server, struct client_t *client);
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void* server_new_client_thread(void *args);
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/* Functions handling communication with clients. */
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73
server.c
73
server.c
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@ -47,8 +47,8 @@ int server_setup(struct server_t *server, unsigned int port) {
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server->port = port;
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fprintf(stderr,"[%s] assigned port %u\n", __func__, server->port); //ntohs(server->address.sin_port)
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/* listen for a client connection, allow 2 connections in queue */
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if (listen(server->socket, 2) == -1) {
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/* listen for a client connection, allow some connections in queue */
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if (listen(server->socket, 1) == -1) {
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fprintf(stderr, "[%s:%d] error %d: %s\n", __func__, __LINE__, errno, strerror(errno));
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return -errno;
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}
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@ -98,58 +98,69 @@ int server_accept(struct server_t *server, struct client_t *accepted_client) {
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/* print client information */
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time2string(accepted_client->last_active, timestamp);
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fprintf(stderr, "[%s] accepted client %s on port %u @ %s\n", __func__,
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accepted_client->ip_string, server->port, timestamp);
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fprintf(stderr, "[%s] accepted client %s @ %s\n",
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__func__, accepted_client->ip_string, timestamp);
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return 0;
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}
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/* Drops current client or rejects new client. */
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int server_drop(struct server_t *server, struct client_t *current_client) {
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/* Thread function handling new client connections. Handles global client variables. */
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void* server_new_client_thread(void *args) {
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struct client_t new_client;
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char msg[DATABUF_LEN];
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char timestamp[TIMESTAMP_LEN];
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struct client_t temp_client;
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/* accept new connection request */
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if (server_accept(server, &new_client) != 0) return -1;
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if (server_accept(&server, &temp_client) != 0) return (void *) -1;
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/* if no client is connected then make new client available for connection */
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if (client.socket == -1) {
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memcpy(&new_client, &temp_client, sizeof(struct client_t));
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return (void *) 0;
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}
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/* if there is already a new client being handled then reject this client request */
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if (new_client.socket != -1) {
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sprintf(msg, "\nToo many connection requests, please try later.\n");
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send(temp_client.socket, msg, strlen(msg), 0);
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client_close(&temp_client);
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time2string(time(NULL), timestamp);
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fprintf(stderr, "[%s] rejected new client request %s @ %s\n",
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__func__, temp_client.ip_string, timestamp);
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return (void *) 0;
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}
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/* make new client available for connection */
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memcpy(&new_client, &temp_client, sizeof(struct client_t));
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/* inform new client that port is already in use */
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time2string(current_client->last_active, timestamp);
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time2string(client.last_active, timestamp);
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sprintf(msg, "\nPort %u is already being used!\nCurrent user and last activity:\n%s @ %s\n",
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server->port, current_client->username, timestamp);
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server.port, client.username, timestamp);
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send(new_client.socket, msg, strlen(msg), 0);
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/* ask new client if current client should be dropped */
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sprintf(msg, "\nDo you want to drop the current user?\nIf yes then please type YES DROP (in uppercase):");
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sprintf(msg, "\nDo you want to drop the current user?\nIf yes then please type YES DROP (in uppercase):\n");
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send(new_client.socket, msg, strlen(msg), 0);
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/* wait for client input */
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if (client_wait_line(&new_client) != 0) return -1;
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client_wait_line(&new_client);
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/* check client confirmation */
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if (strncmp(new_client.data, "YES DROP", 8) == 0) {
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/* current client should be dropped, drop it */
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client_close(current_client);
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time2string(time(NULL), timestamp);
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fprintf(stderr, "[%s] dropped current client %s on port %u @ %s\n", __func__,
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current_client->ip_string, server->port, timestamp);
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/* make new client the current client */
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memcpy(current_client, &new_client, sizeof(struct client_t));
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time2string(time(NULL), timestamp);
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fprintf(stderr, "[%s] accepted new client request %s on port %u @ %s\n", __func__,
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current_client->ip_string, server->port, timestamp);
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/* return 1 because current client was dropped */
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return 1;
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/* drop connected client */
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client_close(&client);
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fprintf(stderr, "[%s] dropped client %s @ %s\n",
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__func__, client.ip_string, timestamp);
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}
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else {
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/* new connection should be rejected, close connection */
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close(new_client.socket);
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/* reject this client request */
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client_close(&new_client);
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time2string(time(NULL), timestamp);
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fprintf(stderr, "[%s] rejected new client request %s on port %u @ %s\n", __func__,
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new_client.ip_string, server->port, timestamp);
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/* return 0 because new client was rejected */
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return 0;
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fprintf(stderr, "[%s] rejected new client request %s @ %s\n",
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__func__, temp_client.ip_string, timestamp);
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return (void *) 1;
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}
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return (void *) 0;
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}
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