550 lines
15 KiB
C
550 lines
15 KiB
C
#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include "telnet.h"
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#define TELNET_PORT 223
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#define RX_BUFFER_SIZE 1024
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#define CMD_SIZE 1024
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#define TEL_PROMPT "admin@telnet:~$ "
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#define PASSWD "admin"
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// extern void printp(char *format, ...);
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// #define debug_print(fmt, ...) printp(fmt, ##__VA_ARGS__)
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// #define debug_print(fmt...) printp(...)
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#define debug_print(fmt, ...) printf(fmt, ##__VA_ARGS__)
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typedef struct telnet_t
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{
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struct sockaddr_in server_addr;
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int sock_server;
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struct sockaddr_in client_addr;
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int sock_client;
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unsigned char rec_buff[RX_BUFFER_SIZE];
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int rec_len;
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unsigned char cmd_buff[CMD_SIZE];
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int cmd_pos;
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unsigned short win_width;
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unsigned short win_height;
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unsigned char cilent_type_name[10];
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char cilent_type;
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char *passwd;
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char passwd_pos;
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char *tel_prompt;
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char init : 1;
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char login_in : 1;
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char tel_login_show : 1;
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char f_echo : 1;
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} telnet_t;
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telnet_t telnet = {
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.passwd = PASSWD,
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.tel_prompt = TEL_PROMPT,
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};
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int telnet_init(telnet_t *tel, int port)
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{
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int telnet_addr_len = sizeof(struct sockaddr_in);
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// server socket create
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tel->sock_server = socket(AF_INET, SOCK_STREAM, 0);
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if (tel->sock_server < 0)
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{
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debug_print("telnet: opening socket");
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return -1;
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}
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// server socket set
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int keepalive = 1;
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if (setsockopt(tel->sock_server, SOL_SOCKET, SO_REUSEADDR, (void *)&keepalive, sizeof(keepalive)) < 0)
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{
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debug_print("telnet:set socket keepalive failed\n");
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return -1;
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}
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// server socket bind and start listen
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tel->server_addr.sin_family = AF_INET;
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tel->server_addr.sin_port = htons(port);
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tel->server_addr.sin_addr.s_addr = INADDR_ANY;
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if (bind(tel->sock_server, (void *)&tel->server_addr, sizeof(tel->server_addr)))
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{
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debug_print("error: binding tcp socket ");
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return -1;
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}
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if (listen(tel->sock_server, 1) == -1)
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{
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debug_print("error: listen");
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return -1;
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}
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debug_print("telnet: telnet server init success\n");
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tel->init = 1;
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return 0;
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}
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#define send_will(buf, a) \
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{ \
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buf[0] = IAC; \
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buf[1] = WILL; \
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buf[2] = a; \
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send(tel->sock_client, buf, 3, 0); \
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};
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#define send_wont(buf, a) \
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{ \
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buf[0] = IAC; \
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buf[1] = WONT; \
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buf[2] = a; \
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send(tel->sock_client, buf, 3, 0); \
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};
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#define send_do(buf, a) \
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{ \
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buf[0] = IAC; \
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buf[1] = DO; \
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buf[2] = a; \
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send(tel->sock_client, buf, 3, 0); \
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};
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#define send_dont(buf, a) \
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{ \
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buf[0] = IAC; \
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buf[1] = DONT; \
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buf[2] = a; \
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send(tel->sock_client, buf, 3, 0); \
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};
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int read_terminal_type(telnet_t *tel)
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{
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unsigned char terminal[] = {IAC, SB, TELOPT_TTYPE, 1, IAC, SE};
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send(tel->sock_client, terminal, sizeof(terminal), 0);
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sleep(1);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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if (tel->rec_len < 0)
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{
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debug_print("error \n");
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return -1;
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}
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}
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int telnet_config(telnet_t *tel)
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{
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if (tel->sock_client < 0)
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{
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return -1;
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}
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unsigned char cmd[3];
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// send_dont(cmd, TELOPT_LINEMODE);
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// send(tel->sock_client,"\033[7e",sizeof("\033[7e"),0);
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// send_do(cmd, 24);
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send_will(cmd, TELOPT_ECHO);
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send_will(cmd, TELOPT_SGA);
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send_wont(cmd, TELOPT_LINEMODE);
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// unsigned char line_mode={IAC,SB,TELOPT_LINEMODE,1,0xf,IAC,SE};
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// send(tel->sock_client,line_mode,sizeof(line_mode),0);
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// 清理下之前的信息
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// tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_do(cmd, TELOPT_TTYPE);
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// 获取下终端类型
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unsigned char terminal[] = {IAC, SB, TELOPT_TTYPE, 1, IAC, SE};
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send(tel->sock_client, terminal, sizeof(terminal), 0);
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// send_wont(cmd, TELOPT_LINEMODE);
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// send_dont(cmd, TELOPT_LINEMODE);
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// send
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// send
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#if 0
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/**
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* 客户端会按照顺序进行回复
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*/
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unsigned char cmd[3];
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send_do(cmd, 24);
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send_do(cmd, 32);
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send_do(cmd, 35);
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send_do(cmd, 39);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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tel->cilent_type = 0;
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if (tel->rec_len < 0)
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{
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return -1;
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}
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else
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{
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if (tel->rec_len == 12)
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{
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int i = 0;
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for (; i < 12; i++)
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{
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if (tel->rec_buff[i] == 32 && tel->rec_buff[i - 1] == WONT)
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{
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// busy client
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tel->cilent_type = 1;
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}
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}
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}
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else
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{
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tel->cilent_type = 2;
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}
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}
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// cilent_type = 3;
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switch (tel->cilent_type)
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{
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case 0:
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send_will(cmd, 3);
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send_do(cmd, 1);
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send_do(cmd, 31);
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send_will(cmd, 5);
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send_do(cmd, 33);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_will(cmd, 1);
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break;
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case 1:
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send_will(cmd, 3);
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send_do(cmd, 1);
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send_do(cmd, 31);
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send_will(cmd, 5);
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send_do(cmd, 33);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_will(cmd, 1);
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break;
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case 2:
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send_do(cmd, 31);
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send_will(cmd, 1);
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send_do(cmd, 3);
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send_will(cmd, 3);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_do(cmd, 1);
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send_do(cmd, 31);
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send_will(cmd, 5);
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send_do(cmd, 33);
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break;
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case 3:
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send_do(cmd, 31);
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send_will(cmd, 3);
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send_do(cmd, 1);
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send_do(cmd, 31);
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send_will(cmd, 5);
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send_do(cmd, 33);
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send_dont(cmd, 1);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_dont(cmd, 1);
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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send_will(cmd, 1);
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break;
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default:
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break;
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}
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return 0;
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#endif
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}
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int telnet_cmd_handle(telnet_t *tel)
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{
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send(tel->sock_client, tel->cmd_buff, tel->cmd_pos, 0);
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tel->cmd_pos = 0;
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}
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int telnet_shell_handle(telnet_t *tel, char c)
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{
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if (c == 13)
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{
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send(tel->sock_client, "\r\n", 2, 0);
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telnet_cmd_handle(tel);
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send(tel->sock_client, "\r\n", 2, 0);
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// send(tel->sock_client,"123",3,0);
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send(tel->sock_client, tel->tel_prompt, sizeof(TEL_PROMPT), 0);
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// send(tel->sock_client, " ", 1, 0);
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unsigned char clear_line[] = "\r\033[K";
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send(tel->sock_client, clear_line, sizeof(clear_line), 0);
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return;
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}
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else if (c == 0)
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{
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send(tel->sock_client, " ", 1, 0);
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}
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else if (c == 10)
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{
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send(tel->sock_client, " ", 1, 0);
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}
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else if (c == 9)
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{
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}
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else
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{
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if (tel->cmd_pos < CMD_SIZE)
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{
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tel->cmd_buff[tel->cmd_pos++] = c;
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send(tel->sock_client, &c, 1, 0);
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send(tel->sock_client, " ", 1, 0);
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}
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else
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{
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send(tel->sock_client, " ", 2, 0);
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}
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}
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}
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int telnet_nor_handle(telnet_t *tel, char c)
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{
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if (tel->f_echo == 0)
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{
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char cmd[3] = {0x08, ' ', 0x08};
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send(tel->sock_client, cmd, 3, 0);
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}
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if (tel->login_in == 0)
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{
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if (tel->tel_login_show == 0)
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{
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char cmd[] = "\033[?25l";
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send(tel->sock_client, cmd, sizeof(cmd), 0);
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tel->tel_login_show = 1;
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}
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// 无论如何回复一个空格
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send(tel->sock_client, " ", 1, 0);
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if (tel->passwd[tel->passwd_pos] == c)
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{
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tel->passwd_pos++;
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if (tel->passwd[tel->passwd_pos] == '\0')
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{
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tel->login_in = 1;
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tel->passwd_pos = 0;
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send(tel->sock_client, "\r\nlogin success\r\n", 17, 0);
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send(tel->sock_client, tel->tel_prompt, sizeof(TEL_PROMPT), 0);
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if (tel->tel_login_show == 1)
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{
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char cmd[] = "\033[?25h";
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send(tel->sock_client, cmd, sizeof(cmd), 0);
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tel->tel_login_show = 0;
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}
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}
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}
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else
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{
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tel->passwd_pos = 0;
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}
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}
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else
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{
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// telnet_shell_handle(tel, c);
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// char see = 0;
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telnet_shell_handle(tel, c);
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}
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}
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int telnet_rec_handle(telnet_t *tel, unsigned char *c, int len)
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{
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#define MOD_NORMAL 0
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#define MOD_IAC 1
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#define MOD_WILL 2
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#define MOD_WONT 3
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#define MOD_DO 4
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#define MOD_DONT 5
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#define MOD_SB 6
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int state = MOD_NORMAL;
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for (int i = 0; i < len; i++)
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{
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switch (state)
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{
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case MOD_NORMAL:
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if (c[i] == IAC)
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{
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state = MOD_IAC;
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}
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else
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{
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telnet_nor_handle(tel, c[i]);
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}
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break;
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case MOD_IAC:
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if (c[i] == IAC)
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{
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state = MOD_NORMAL;
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// 2个IAC代表字符255，也需要进行处理
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telnet_nor_handle(tel, c[i]);
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}
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else if (c[i] == DO)
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{
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state = MOD_DO;
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}
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else if (c[i] == DONT)
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{
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state = MOD_DONT;
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}
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else if (c[i] == WILL)
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{
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state = MOD_WILL;
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}
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else if (c[i] == WONT)
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{
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state = MOD_WONT;
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}
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else if (c[i] == SB)
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{
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state = MOD_SB;
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}
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else
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{
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state = MOD_NORMAL;
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telnet_nor_handle(tel, c[i]);
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}
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break;
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case MOD_WILL:
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debug_print("telnet: WILL %d\n", c[i]);
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if (c[i] == TELOPT_NAWS)
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{
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if (c[i + 1] == IAC && c[i + 2] == SB && c[i + 3] == TELOPT_NAWS && c[i + 8] == IAC && c[i + 9] == SE)
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{
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tel->win_width = ((unsigned short)c[i + 4] << 8) + (unsigned short)c[i + 5];
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tel->win_height = ((unsigned short)c[i + 6] << 8) + (unsigned short)c[i + 7];
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i = i + 9;
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debug_print("telnet: win_width = %d, win_height = %d\n", tel->win_width, tel->win_height);
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}
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}
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state = MOD_NORMAL;
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break;
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case MOD_WONT:
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debug_print("telnet: WONT %d\n", c[i]);
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state = MOD_NORMAL;
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break;
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case MOD_DO:
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debug_print("telnet: DO %d\n", c[i]);
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state = MOD_NORMAL;
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break;
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case MOD_DONT:
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if (c[i] == TELOPT_ECHO)
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{
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tel->f_echo = 0;
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}
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debug_print("telnet: DONT %d\n", c[i]);
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state = MOD_NORMAL;
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break;
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case MOD_SB:
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if (c[i] == TELOPT_TTYPE && c[i + 1] == 0)
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{
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i = i + 2;
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int k = 0;
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// 客户端类型
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while (1)
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{
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if ((c[i] == IAC && c[i + 1] == SE) || i == len)
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{
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tel->cilent_type_name[k] = '\0';
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printf("telnet: client type = %s\n", tel->cilent_type_name);
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break;
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}
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if (i == len)
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{
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break;
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}
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tel->cilent_type_name[k] = c[i];
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i++;
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k++;
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}
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}
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break;
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}
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}
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}
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int telnet_core(telnet_t *tel)
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{
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while (1)
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{
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if (tel->init == 0)
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{
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sleep(1);
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continue;
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}
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debug_print("\ntelnet: waiting for connection\n");
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while (1)
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{
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int addr_len = sizeof(tel->client_addr);
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tel->sock_client = accept(tel->sock_server, (void *)&tel->client_addr, &addr_len);
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if (tel->sock_client < 0)
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{
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sleep(1);
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continue;
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}
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else
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{
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break;
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}
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}
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debug_print("telnet: new telnet client(%s:%d) connection, switch console to telnet...\n", inet_ntoa(tel->client_addr.sin_addr), tel->client_addr.sin_port);
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int ret = telnet_config(tel);
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if (ret < 0)
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{
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debug_print("telnet: client disconnected\n");
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close(tel->sock_client);
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continue;
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}
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if (tel->login_in == 0)
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{
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send(tel->sock_client, "admin login: \r\n", 15, 0);
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}
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while (1)
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{
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// telnet_host_function();
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tel->rec_len = recv(tel->sock_client, tel->rec_buff, RX_BUFFER_SIZE, 0);
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// if (tel->rec_buff[0] == IAC && tel->rec_buff[1] != IAC)
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// {
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// telnet_config_back(tel);
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// }
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if (tel->rec_len > 0)
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{
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debug_print("telnet: recv_len = %d\n", tel->rec_len);
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for (int i = 0; i < tel->rec_len; i++)
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{
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switch (tel->rec_buff[i])
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{
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case IAC:
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debug_print("IAC,");
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break;
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case DO:
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debug_print("DO,");
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break;
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case DONT:
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debug_print("DONT,");
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break;
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case WILL:
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debug_print("WILL,");
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break;
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case WONT:
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debug_print("WONT,");
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break;
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case SB:
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debug_print("SB,");
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break;
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case SE:
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debug_print("SE,");
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break;
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default:
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debug_print("%d,", tel->rec_buff[i]);
|
||
break;
|
||
}
|
||
}
|
||
debug_print("\n");
|
||
telnet_rec_handle(tel, tel->rec_buff, tel->rec_len);
|
||
}
|
||
else
|
||
{
|
||
debug_print("telnet: client disconnected\n");
|
||
tel->login_in = 0;
|
||
close(tel->sock_client);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
int main()
|
||
{
|
||
telnet_init(&telnet, TELNET_PORT);
|
||
telnet_core(&telnet);
|
||
return 0;
|
||
}
|
||
|