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added support for dropp current client - needs a separate thread to remove blocking

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This commit is contained in:
Igor Socec 2014-04-04 16:27:02 +02:00
parent 9114998d1f
commit 86f0bc612f
4 changed files with 124 additions and 49 deletions
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71
client.c
View file

@ -83,45 +83,66 @@ int client_write(struct client_t *client, char *databuf, int datalen) {
return len; return len;
} }
/* Waits for client input in "line mode". Blocks until input arrives. */
int client_wait_line(struct client_t *client) {
int ret;
fd_set read_fds;
client->data[0] = '\0';
/* loop waiting for client input */
while (client->data[0] == '\0') {
/* setup select() parameters */
FD_ZERO(&read_fds);
FD_SET(client->socket, &read_fds);
/* send prompt character to client */
client_write(client, "> ", 2);
/* block until input arrives */
if (select((client->socket)+1, &read_fds, NULL, NULL, NULL) == -1) return -1;
if (FD_ISSET(client->socket, &read_fds)) {
/* read client input */
ret = client_read(client);
if (ret == -1) return -1;
/* we don't want empty data so stop on \r or \n */
if ( (client->data[0] == '\r') || (client->data[0] == '\n') ) {
fprintf(stderr, "client data is empty\n");
client->data[0] = '\0';
}
}
}
fprintf(stderr, "client data: %s\n", client->data);
return 0;
}
/* Waits for client to provide a username. Blocks until a username is entered. */ /* Waits for client to provide a username. Blocks until a username is entered. */
int client_ask_username(struct client_t *client) { int client_ask_username(struct client_t *client) {
int i; int i;
char databuf[DATABUF_LEN]; char msg[DATABUF_LEN];
fd_set read_fds;
/* send username request to client */ /* send username request to client */
snprintf(databuf, DATABUF_LEN, snprintf(msg, DATABUF_LEN,
"\nPlease provide a username to identify yourself to other users (max %d characters):\n", USERNAME_LEN); "\nPlease provide a username to identify yourself to other users (max %d characters):\n", USERNAME_LEN);
client_write(client, databuf, strlen(databuf)); client_write(client, msg, strlen(msg));
/* wait for client input */ /* wait for client input */
client->username[0] = '\0'; if (client_wait_line(client) != 0) return -1;
while (client->username[0] == '\0') {
/* send prompt character to client */ /* save received data as client username */
snprintf(databuf, DATABUF_LEN, "> "); for (i = 0; i < USERNAME_LEN; i++) {
client_write(client, databuf, strlen(databuf)); if ( (client->data[i] == '\r') || (client->data[i] == '\n') ) {
/* setup select() parameters */ /* don't include \r or \n in username */
FD_ZERO(&read_fds); client->username[i] = '\0';
FD_SET(client->socket, &read_fds); break;
select((client->socket)+1, &read_fds, NULL, NULL, NULL);
if (FD_ISSET(client->socket, &read_fds)) {
client_read(client);
/* handle client input */
for (i = 0; i < USERNAME_LEN; i++) {
if (client->data[i] == '\r') {
break;
}
client->username[i] = client->data[i];
}
client->username[i+1] = '\0';
} }
client->username[i] = client->data[i];
} }
/* send welcome message to client */ /* send welcome message to client */
snprintf(databuf, DATABUF_LEN, snprintf(msg, DATABUF_LEN,
"\nWelcome %s!\n\n", client->username); "\nWelcome %s!\n\n", client->username);
client_write(client, databuf, strlen(databuf)); client_write(client, msg, strlen(msg));
return 0; return 0;
} }

17
moxerver.c
View file

@ -215,9 +215,22 @@ int main(int argc, char *argv[]) {
/* put client in "character" mode */ /* put client in "character" mode */
telnet_set_character_mode(&client); telnet_set_character_mode(&client);
} }
/* reject connection request if a client is already connected */ /* if a client is already connected then new clients need to be handled */
else { else {
server_reject(&server, &client); /* decide if current client needs to be dropped or new client needs to be rejected */
ret = server_drop(&server, &client);
if (ret < 0) {
/* error in handling new clients, print but continue waiting for new clients */
fprintf(stderr, "[%s] problem handling new client request\n", NAME);
continue;
}
/* if current client was dropped we need to set up new client */
if (ret > 0) {
/* ask client to provide a username before going to "character" mode */
client_ask_username(&client);
/* put client in "character" mode */
telnet_set_character_mode(&client);
}
} }
} }
/* check client status if connected */ /* check client status if connected */

22
moxerver.h
View file

@ -91,12 +91,15 @@ int server_close(struct server_t *server);
int server_accept(struct server_t *server, struct client_t *accepted_client); int server_accept(struct server_t *server, struct client_t *accepted_client);
/** /**
* Rejects incoming client connection. * Asks new incoming client connection if current client needs to be dropped.
* If current client doesn't need to be dropped then new client is rejected.
* *
* Returns: * Returns:
* 0 always, errors with rejected client are ignored * - positive value if current client was dropped
* - 0 if new client was rejected
* - negative value if error occurred
*/ */
int server_reject(struct server_t *server, struct client_t *client); int server_drop(struct server_t *server, struct client_t *client);
/* Functions handling communication with clients. */ /* Functions handling communication with clients. */
@ -129,12 +132,23 @@ int client_read(struct client_t *client);
*/ */
int client_write(struct client_t *client, char *databuf, int datalen); int client_write(struct client_t *client, char *databuf, int datalen);
/**
* Waits for client input in "line mode", where client sends a whole line of characters.
* Blocks until input arrives.
*
* Returns:
* - 0 on success
* - negative value if error occurred
*/
int client_wait_line(struct client_t *client);
/** /**
* Waits for client to provide a username. * Waits for client to provide a username.
* Blocks until a username is entered. * Blocks until a username is entered.
* *
* Returns: * Returns:
* 0 always * - 0 on success
* - negative value if error occurred
*/ */
int client_ask_username(struct client_t *client); int client_ask_username(struct client_t *client);

63
server.c
View file

@ -103,26 +103,53 @@ int server_accept(struct server_t *server, struct client_t *accepted_client) {
return 0; return 0;
} }
/* Rejects incoming client connection. Errors with rejected client are ignored. */ /* Drops current client or rejects new client. */
int server_reject(struct server_t *server, struct client_t *client) { int server_drop(struct server_t *server, struct client_t *current_client) {
int namelen; struct client_t new_client;
struct client_t rclient; char msg[DATABUF_LEN];
char reject_msg[128];
char timestamp[TIMESTAMP_LEN]; char timestamp[TIMESTAMP_LEN];
/* accept connection request */ /* accept new connection request */
namelen = sizeof(rclient.address); if (server_accept(server, &new_client) != 0) return -1;
rclient.socket = accept(server->socket, (struct sockaddr *) &rclient.address, (socklen_t *) &namelen);
/* send reject message to client */ /* inform new client that port is already in use */
time2string(client->last_active, timestamp); time2string(current_client->last_active, timestamp);
sprintf(reject_msg, "\nPort %u is already being used:\ncurrent user: %s\nlast activity: @ %s\n\n", sprintf(msg, "\nPort %u is already being used!\nCurrent user and last activity:\n%s @ %s\n",
server->port, client->username, timestamp); server->port, current_client->username, timestamp);
send(rclient.socket, reject_msg, strlen(reject_msg), 0); send(new_client.socket, msg, strlen(msg), 0);
/* close connection */
close(rclient.socket); /* ask new client if current client should be dropped */
sprintf(msg, "\nDo you want to drop the current user?\nIf yes then please type YES DROP (in uppercase):");
send(new_client.socket, msg, strlen(msg), 0);
/* wait for client input */
if (client_wait_line(&new_client) != 0) return -1;
/* check client confirmation */
if (strncmp(new_client.data, "YES DROP", 8) == 0) {
/* current client should be dropped, drop it */
client_close(current_client);
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] dropped current client %s on port %u @ %s\n", __func__,
current_client->ip_string, server->port, timestamp);
/* make new client the current client */
memcpy(current_client, &new_client, sizeof(struct client_t));
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] accepted new client request %s on port %u @ %s\n", __func__,
current_client->ip_string, server->port, timestamp);
/* return 1 because current client was dropped */
return 1;
}
else {
/* new connection should be rejected, close connection */
close(new_client.socket);
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] rejected new client request %s on port %u @ %s\n", __func__,
new_client.ip_string, server->port, timestamp);
/* return 0 because new client was rejected */
return 0;
}
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] rejected new client request @ %s\n", __func__, timestamp);
return 0;
} }