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Line 52... |
#include "telnet.h"
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#include "telnet.h"
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/* Global variables */
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/* Global variables */
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int tcp_checksum_errors_g = 0;
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int tcp_checksum_errors_g = 0;
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socket_t* first_socket_g;
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socket_t* socket1_g;
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/* input argument is a pointer to the previous socket,
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if this is the first socket object, then it is NULL */
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socket_t* new_socket(socket_t* prev)
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{
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socket_t* socket;
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int i;
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socket = (socket_t*) malloc(sizeof(socket_t));
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socket->rx_packet = (packet_t*) malloc(sizeof(packet_t));
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/* Create space for an array of pointers */
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socket->tcp_buf = malloc (TCP_TX_BUFFERS * sizeof (void *));
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/* Create space for a set of buffers, each pointed to by an element of the array */
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for (i=0;i<TCP_TX_BUFFERS;i=i+1) {
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socket->tcp_buf[i] = (packet_buffer_t*) malloc (sizeof (packet_buffer_t));
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socket->tcp_buf[i]->payload_valid = 0;
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socket->tcp_buf[i]->starting_seq = 0;
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socket->tcp_buf[i]->ending_seq = 0;
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socket->tcp_buf[i]->len_bytes = 0;
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socket->tcp_buf[i]->ack_received = 0;
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}
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socket->telnet_txbuf = init_line_buffer(0x80000);
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socket->telnet_rxbuf = init_line_buffer(0x1000);
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socket->packets_sent = 0;
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socket->packets_received = 0;
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socket->packets_resent = 0;
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socket->telnet_sent_opening_message = 0;
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socket->telnet_echo_mode = 0;
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socket->telnet_connection_state = TELNET_CLOSED;
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socket->telnet_options_sent = 0;
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socket->tcp_current_buf = 0;
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socket->tcp_reset = 0;
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socket->tcp_connection_state = TCP_CLOSED;
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socket->tcp_disconnect = 0;
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socket->tcp_seq = 0x100; /* should be random initial seq number for tcp */
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socket->tcp_last_seq = socket->tcp_seq;
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socket->tcp_last_ack = 0;
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/* Chain the socket objects together */
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if (prev == NULL){
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socket->first = socket;
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socket->id = 0;
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}
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else {
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socket->first = prev->first;
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socket->id = prev->id + 1;
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prev->next = socket;
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}
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socket->next = NULL;
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return socket;
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}
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/* All received tcp packets with dset ip == me arrive here */
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void parse_tcp_packet(char * buf, packet_t* rx_packet)
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void parse_tcp_packet(char * buf, packet_t* rx_packet)
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{
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{
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int i;
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int i;
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int ptr;
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int ptr;
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socket_t* socket;
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socket_t* socket;
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int found=0;
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/* TCP Length */
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/* TCP Length */
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rx_packet->tcp_len = rx_packet->ip_len - rx_packet->ip_header_len*4;
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rx_packet->tcp_len = rx_packet->ip_len - rx_packet->ip_header_len*4;
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rx_packet->tcp_hdr_len = (buf[12]>>4)*4;
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rx_packet->tcp_hdr_len = (buf[12]>>4)*4;
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| Line 73... |
Line 136... |
rx_packet->tcp_payload_len = 0;
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rx_packet->tcp_payload_len = 0;
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/* Verify the TCP checksum is correct */
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/* Verify the TCP checksum is correct */
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if (tcp_checksum(buf, rx_packet, 0)) {
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if (tcp_checksum(buf, rx_packet, 0)) {
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tcp_checksum_errors_g++;
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tcp_checksum_errors_g++;
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goto error_out;
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return;
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}
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}
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rx_packet->tcp_src_port = buf[0]<<8|buf[1];
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rx_packet->tcp_src_port = buf[0]<<8|buf[1];
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rx_packet->tcp_dst_port = buf[2]<<8|buf[3];
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rx_packet->tcp_dst_port = buf[2]<<8|buf[3];
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| Line 85... |
Line 148... |
rx_packet->tcp_ack = buf[8]<<24|buf[9]<<16|buf[10]<<8|buf[11];
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rx_packet->tcp_ack = buf[8]<<24|buf[9]<<16|buf[10]<<8|buf[11];
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rx_packet->tcp_flags = buf[13];
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rx_packet->tcp_flags = buf[13];
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rx_packet->tcp_window_size = buf[14]<<8|buf[15];
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rx_packet->tcp_window_size = buf[14]<<8|buf[15];
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/* only interested in telnet packet to dest port xx */
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if (rx_packet->tcp_dst_port != 23) {
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return;
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}
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if (rx_packet->tcp_hdr_len > 20) {
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if (rx_packet->tcp_hdr_len > 20) {
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/* Get the source time stamp */
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/* Get the source time stamp */
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parse_tcp_options(buf, rx_packet);
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parse_tcp_options(buf, rx_packet);
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}
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}
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/* --------------------------------------------------
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/* --------------------------------------------------
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Assign the received packet to a socket
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Assign the received packet to a socket
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-------------------------------------------------- */
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-------------------------------------------------- */
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/* seach for an open socket that matches the tcp connection */
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socket = first_socket_g;
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for(;;){
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if (socket->tcp_connection_state != TCP_CLOSED &&
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socket->rx_packet->tcp_src_port == rx_packet->tcp_src_port) {
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found=1;
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break;
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}
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if (socket->next!=NULL)
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socket=socket->next;
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else
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break;
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}
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/* socket 0 open and matches ? */
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if (socket0_g->tcp_connection_state != TCP_CLOSED &&
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/* Search for an available closed soeckt to reuse */
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socket0_g->rx_packet->tcp_src_port == rx_packet->tcp_src_port)
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if (!found){
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socket = socket0_g;
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socket = first_socket_g;
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for(;;){
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/* socket 1 open and matches ? */
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if (socket->tcp_connection_state == TCP_CLOSED) {
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else if (socket1_g->tcp_connection_state != TCP_CLOSED &&
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found=1;
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socket1_g->rx_packet->tcp_src_port == rx_packet->tcp_src_port)
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break;
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socket = socket1_g;
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}
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if (socket->next!=NULL)
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/* no matches. Pick an unused socket */
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socket=socket->next;
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else if (socket0_g->tcp_connection_state == TCP_CLOSED)
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socket = socket0_g;
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else if (socket1_g->tcp_connection_state == TCP_CLOSED)
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socket = socket1_g;
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else
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else
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goto error_out;
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break;
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}
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}
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/* All available sockets being used. Add a new one to the end of the chain */
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if (!found) {
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socket = new_socket(socket);
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}
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/* Copy the rx_packet structure into the socket */
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/* Copy the rx_packet structure into the socket */
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memcpy(socket->rx_packet, rx_packet, sizeof(packet_t));
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memcpy(socket->rx_packet, rx_packet, sizeof(packet_t));
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tcp_response(buf, socket);
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tcp_response(buf, socket);
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error_out:
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return;
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}
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}
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/* Get the tcp source time stamp by walking through the options */
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/* Get the tcp source time stamp by walking through the options */
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void parse_tcp_options(char * buf, packet_t* rx_packet)
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void parse_tcp_options(char * buf, packet_t* rx_packet)
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| Line 579... |
Line 661... |
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return header_checksum16(buf, len_tcp, sum);
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return header_checksum16(buf, len_tcp, sum);
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}
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}
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No newline at end of file
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No newline at end of file
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/* handle tcp connections and process buffers
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Poll all sockets in turn for activity */
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void process_tcp(socket_t* socket)
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{
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/* Check if any tcp packets need to be re-transmitted */
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tcp_retransmit(socket);
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/* Handle exit command */
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if (socket->tcp_disconnect && socket->tcp_connection_state == TCP_OPEN) {
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tcp_disconnect(socket);
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}
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/* Reset connection */
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else if (socket->tcp_reset) {
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socket->tcp_connection_state = TCP_CLOSED;
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socket->telnet_connection_state = TELNET_CLOSED;
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socket->telnet_options_sent = 0;
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tcp_reply(socket, NULL, 0);
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socket->tcp_reset = 0;
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}
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/* handle telnet messages */
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else if (socket->tcp_connection_state == TCP_OPEN){
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process_telnet(socket);
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}
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}
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No newline at end of file
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No newline at end of file
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