openwrt里用的以太网转串口代码

/* * ser2net - A program for allowing telnet connection to serial ports * Copyright (C) 2001 Corey Minyard <minyard@acm.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* This code handles the actual transfer of data between the serial ports and the TCP ports. */ #include <sys/time.h> #include <arpa/inet.h> #include <stdlib.h> #include <stdbool.h> #include <unistd.h> #include <stdio.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <errno.h> #include <syslog.h> #include <string.h> #include <ctype.h> #include <time.h> #include <fcntl.h> #include "ser2net.h" #include "dataxfer.h" #include "selector.h" #include "utils.h" #include "telnet.h" #include "devio.h" #include "buffer.h" #include "locking.h" #include "led.h" #define SERIAL "term" #define NET "tcp " /** BASED ON sshd.c FROM openssh.com */ #ifdef HAVE_TCPD_H #include <tcpd.h> static char *progname = "ser2net"; #endif /* HAVE_TCPD_H */ /* States for the net_to_dev_state and dev_to_net_state. */ #define PORT_UNCONNECTED 0 /* The TCP port is not connected to anything right now. */ #define PORT_WAITING_INPUT 1 /* Waiting for input from the input side. */ #define PORT_WAITING_OUTPUT_CLEAR 2 /* Waiting for output to clear so I can send data. */ #define PORT_CLOSING 3 /* Waiting for output close string to be sent. */ char *state_str[] = { "unconnected", "waiting input", "waiting output", "closing" }; #define PORT_DISABLED 0 /* The port is not open. */ #define PORT_RAW 1 /* Port will not do telnet negotiation. */ #define PORT_RAWLP 2 /* Port will not do telnet negotiation and termios setting, open for output only. */ #define PORT_TELNET 3 /* Port will do telnet negotiation. */ char *enabled_str[] = { "off", "raw", "rawlp", "telnet" }; typedef struct trace_info_s { int hexdump; /* output each block as a hexdump */ int timestamp; /* preceed each line with a timestamp */ char *filename; /* open file. NULL if not used */ int fd; /* open file. -1 if not used */ } trace_info_t; typedef struct port_info port_info_t; typedef struct net_info net_info_t; struct net_info { port_info_t *port; /* My port. */ bool closing; /* Is the connection in the process of closing? */ int fd; /* When connected, the file descriptor for the network port used for I/O. */ bool remote_fixed; /* Tells if the remote address was set in the configuration, and cannot be changed. */ struct sockaddr_storage remote; /* The socket address of who is connected to this port. */ struct sockaddr *raddr; /* Points to remote, for convenience. */ socklen_t raddrlen; struct sockaddr *udpraddr; /* Points to remote, only for UDP, so sendto's addr will be NULL on TCP. */ socklen_t udpraddrlen; unsigned int bytes_received; /* Number of bytes read from the network port. */ unsigned int bytes_sent; /* Number of bytes written to the network port. */ struct sbuf *banner; /* Outgoing banner */ unsigned int write_pos; /* Our current position in the output buffer where we need to start writing next. */ bool data_to_write; /* There is data to write on this network port. */ void (*write_handler)(port_info_t *, net_info_t *); /* Data for the telnet processing */ telnet_data_t tn_data; bool sending_tn_data; /* Are we sending tn data at the moment? */ int timeout_left; /* The amount of time left (in seconds) before the timeout goes off. */ sel_runner_t *runshutdown; /* Used to run things at the base context. This way we don't have to worry that we are running inside a handler context that needs to be waited for exit. */ /* * If a user gets kicked, store the information for the new user * here since we have already accepted the connection or received * the packet, we have to store it someplace. */ int new_fd; struct sockaddr_storage new_remote; socklen_t new_raddrlen; unsigned char *new_buf; int new_buf_len; }; struct port_remaddr { char *name; struct sockaddr_storage addr; socklen_t addrlen; bool is_port_set; struct port_remaddr *next; }; struct port_info { DEFINE_LOCK(, lock) int enabled; /* If PORT_DISABLED, the port is disabled and the TCP accept port is not operational. If PORT_RAW, the port is enabled and will not do any telnet negotiations. If PORT_RAWLP, the port is enabled only for output without any termios setting - it allows to redirect /dev/lpX devices If PORT_TELNET, the port is enabled and it will do telnet negotiations. */ int timeout; /* The number of seconds to wait without any I/O before we shut the port down. */ sel_timer_t *timer; /* Used to timeout when the no I/O has been seen for a certain period of time. */ sel_timer_t *send_timer; /* Used to delay a bit when waiting for characters to batch up as many characters as possible. */ bool send_timer_running; sel_runner_t *runshutdown; /* Used to run things at the base context. This way we don't have to worry that we are running inside a handler context that needs to be waited for exit. */ int chardelay; /* The amount of time to wait after receiving a character before sending it, unless we receive another character. Based on bit rate. */ int bps; /* Bits per second rate. */ int bpc; /* Bits per character. */ bool enable_chardelay; int chardelay_scale; /* The number of character periods to wait for the next character, in tenths of a character period. */ int chardelay_min; /* The minimum chardelay, in microseconds. */ int chardelay_max; /* Maximum amount of time to wait before sending the data. */ struct timeval send_time; /* When using chardelay, the time when we will send the data, no matter what, set by chardelay_max. */ int (*netread)(int fd, port_info_t *port, int *readerr, net_info_t **netcon); struct port_remaddr *remaddrs; bool remaddr_set; /* Information about the network port. */ char *portname; /* The name given for the port. */ int is_stdio; /* Do stdio on the port? */ struct addrinfo *ai; /* The address list for the portname. */ bool dgram; /* Is this a datagram (UDP) port? */ struct opensocks *acceptfds; /* The file descriptor used to accept connections on the TCP port. */ unsigned int nr_acceptfds; waiter_t *accept_waiter; /* Wait for accept changes. */ unsigned int max_connections; /* Maximum number of TCP connections we can