added support for dropp current client - needs a separate thread to remove blocking
This commit is contained in:
Igor Socec
parent
9114998d1f
commit
86f0bc612f
4 changed files with 124 additions and 49 deletions
71
client.c
71
client.c
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@ -83,45 +83,66 @@ int client_write(struct client_t *client, char *databuf, int datalen) {
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return len;
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}
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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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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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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 (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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/* 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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/* Waits for client to provide a username. Blocks until a username is entered. */
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int client_ask_username(struct client_t *client) {
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int i;
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char databuf[DATABUF_LEN];
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fd_set read_fds;
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char msg[DATABUF_LEN];
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/* send username request to client */
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snprintf(databuf, DATABUF_LEN,
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snprintf(msg, DATABUF_LEN,
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"\nPlease provide a username to identify yourself to other users (max %d characters):\n", USERNAME_LEN);
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client_write(client, databuf, strlen(databuf));
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client_write(client, msg, strlen(msg));
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/* wait for client input */
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client->username[0] = '\0';
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while (client->username[0] == '\0') {
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/* send prompt character to client */
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snprintf(databuf, DATABUF_LEN, "> ");
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client_write(client, databuf, strlen(databuf));
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/* setup select() parameters */
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FD_ZERO(&read_fds);
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FD_SET(client->socket, &read_fds);
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select((client->socket)+1, &read_fds, NULL, NULL, NULL);
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if (FD_ISSET(client->socket, &read_fds)) {
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client_read(client);
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/* handle client input */
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for (i = 0; i < USERNAME_LEN; i++) {
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if (client->data[i] == '\r') {
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break;
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}
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client->username[i] = client->data[i];
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}
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client->username[i+1] = '\0';
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if (client_wait_line(client) != 0) return -1;
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/* save received data as client username */
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for (i = 0; i < USERNAME_LEN; i++) {
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if ( (client->data[i] == '\r') || (client->data[i] == '\n') ) {
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/* don't include \r or \n in username */
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client->username[i] = '\0';
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break;
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}
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client->username[i] = client->data[i];
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}
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/* send welcome message to client */
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snprintf(databuf, DATABUF_LEN,
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snprintf(msg, DATABUF_LEN,
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"\nWelcome %s!\n\n", client->username);
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client_write(client, databuf, strlen(databuf));
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client_write(client, msg, strlen(msg));
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return 0;
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}
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17
moxerver.c
17
moxerver.c
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@ -215,9 +215,22 @@ int main(int argc, char *argv[]) {
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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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/* reject connection request if a client is already connected */
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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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server_reject(&server, &client);
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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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}
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}
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/* check client status if connected */
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22
moxerver.h
22
moxerver.h
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@ -91,12 +91,15 @@ 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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* Rejects incoming client connection.
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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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*
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* Returns:
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* 0 always, errors with rejected client are ignored
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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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*/
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int server_reject(struct server_t *server, struct client_t *client);
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int server_drop(struct server_t *server, struct client_t *client);
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/* Functions handling communication with clients. */
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@ -129,12 +132,23 @@ int client_read(struct client_t *client);
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*/
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int client_write(struct client_t *client, char *databuf, int datalen);
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/**
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* Waits for client input in "line mode", where client sends a whole line of characters.
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* Blocks until input arrives.
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*
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* Returns:
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* - 0 on success
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* - negative value if error occurred
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*/
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int client_wait_line(struct client_t *client);
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/**
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* Waits for client to provide a username.
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* Blocks until a username is entered.
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*
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* Returns:
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* 0 always
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* - 0 on success
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* - negative value if error occurred
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*/
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int client_ask_username(struct client_t *client);
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63
server.c
63
server.c
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@ -103,26 +103,53 @@ int server_accept(struct server_t *server, struct client_t *accepted_client) {
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return 0;
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}
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/* Rejects incoming client connection. Errors with rejected client are ignored. */
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int server_reject(struct server_t *server, struct client_t *client) {
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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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int namelen;
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struct client_t rclient;
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char reject_msg[128];
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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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/* accept connection request */
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namelen = sizeof(rclient.address);
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rclient.socket = accept(server->socket, (struct sockaddr *) &rclient.address, (socklen_t *) &namelen);
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/* send reject message to client */
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time2string(client->last_active, timestamp);
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sprintf(reject_msg, "\nPort %u is already being used:\ncurrent user: %s\nlast activity: @ %s\n\n",
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server->port, client->username, timestamp);
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send(rclient.socket, reject_msg, strlen(reject_msg), 0);
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/* close connection */
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close(rclient.socket);
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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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/* inform new client that port is already in use */
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time2string(current_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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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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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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/* 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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}
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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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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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}
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time2string(time(NULL), timestamp);
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fprintf(stderr, "[%s] rejected new client request @ %s\n", __func__, timestamp);
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return 0;
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}
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