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- /* netcat.c - Forward stdin/stdout to a file or network connection.
- *
- * Copyright 2007 Rob Landley <rob@landley.net>
- *
- * TODO: udp, ipv6, genericize for telnet/microcom/tail-f
- * fix -t, xconnect
- * netcat -L zombies
- USE_NETCAT(OLDTOY(nc, netcat, TOYFLAG_USR|TOYFLAG_BIN))
- USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tElL")"w#<1W#<1p#<1>65535q#<1s:f:46uU"USE_NETCAT_LISTEN("[!tlL][!Lw]")"[!46U]", TOYFLAG_BIN))
- config NETCAT
- bool "netcat"
- default y
- help
- usage: netcat [-46U] [-u] [-wpq #] [-s addr] {IPADDR PORTNUM|-f FILENAME|COMMAND...}
- Forward stdin/stdout to a file or network connection.
- -4 Force IPv4
- -6 Force IPv6
- -f Use FILENAME (ala /dev/ttyS0) instead of network
- -p Local port number
- -q Quit SECONDS after EOF on stdin, even if stdout hasn't closed yet
- -s Local source address
- -u Use UDP
- -U Use a UNIX domain socket
- -w SECONDS timeout to establish connection
- -W SECONDS timeout for more data on an idle connection
- Use "stty 115200 -F /dev/ttyS0 && stty raw -echo -ctlecho" with
- netcat -f to connect to a serial port.
- config NETCAT_LISTEN
- bool "netcat server options (-let)"
- default y
- depends on NETCAT
- help
- usage: netcat [-tElL]
- -l Listen for one incoming connection, then exit
- -L Listen and background each incoming connection (server mode)
- -t Allocate tty
- -E Forward stderr
- When listening the COMMAND line is executed as a child process to handle
- an incoming connection. With no COMMAND -l forwards the connection
- to stdin/stdout. If no -p specified, -l prints the port it bound to and
- backgrounds itself (returning immediately).
- For a quick-and-dirty server, try something like:
- netcat -s 127.0.0.1 -p 1234 -tL sh -l
- */
- #define FOR_netcat
- #include "toys.h"
- GLOBALS(
- char *f, *s;
- long q, p, W, w;
- )
- static void timeout(int signum)
- {
- if (TT.w) error_exit("Timeout");
- xexit();
- }
- static void set_alarm(int seconds)
- {
- xsignal(SIGALRM, seconds ? timeout : SIG_DFL);
- alarm(seconds);
- }
- // open AF_UNIX socket
- static int usock(char *name, int type, int out)
- {
- int sockfd;
- struct sockaddr_un sockaddr;
- memset(&sockaddr, 0, sizeof(struct sockaddr_un));
- if (strlen(name) + 1 > sizeof(sockaddr.sun_path))
- error_exit("socket path too long %s", name);
- strcpy(sockaddr.sun_path, name);
- sockaddr.sun_family = AF_UNIX;
- sockfd = xsocket(AF_UNIX, type, 0);
- (out?xconnect:xbind)(sockfd, (struct sockaddr*)&sockaddr, sizeof(sockaddr));
- return sockfd;
- }
-
- void netcat_main(void)
- {
- int sockfd = -1, in1 = 0, in2 = 0, out1 = 1, out2 = 1, family = AF_UNSPEC,
- ll = FLAG(L)|FLAG(l), type = FLAG(u) ? SOCK_DGRAM : SOCK_STREAM;
- pid_t child;
- // Addjust idle and quit_delay to ms or -1 for no timeout
- TT.W = TT.W ? TT.W*1000 : -1;
- TT.q = TT.q ? TT.q*1000 : -1;
- xsignal(SIGCHLD, SIG_IGN);
- set_alarm(TT.w);
- // The argument parsing logic can't make "<2" conditional on other
- // arguments like -f and -l, so do it by hand here.
- if (FLAG(f) ? toys.optc : (!ll && toys.optc!=(FLAG(U)?1:2)))
- help_exit("bad argument count");
- if (FLAG(4)) family = AF_INET;
- else if (FLAG(6)) family = AF_INET6;
- else if (FLAG(U)) family = AF_UNIX;
- if (TT.f) in1 = out2 = xopen(TT.f, O_RDWR);
- else {
- // Setup socket
- if (!ll) {
- if (FLAG(U)) sockfd = usock(toys.optargs[0], type, 1);
- else sockfd = xconnectany(xgetaddrinfo(toys.optargs[0], toys.optargs[1],
- family, type, 0, 0));
- // We have a connection. Disarm timeout and start poll/send loop.
- set_alarm(0);
- in1 = out2 = sockfd;
- pollinate(in1, in2, out1, out2, TT.W, TT.q);
- } else {
- // Listen for incoming connections
- if (FLAG(U)) {
- if (!FLAG(s)) error_exit("-s must be provided if using -U with -L/-l");
- sockfd = usock(TT.s, type, 0);
- } else {
- sprintf(toybuf, "%ld", TT.p);
- sockfd = xbindany(xgetaddrinfo(TT.s, toybuf, family, type, 0, 0));
- }
- if (listen(sockfd, 5)) error_exit("listen");
- if (!TT.p && !FLAG(U)) {
- struct sockaddr* address = (void*)toybuf;
- socklen_t len = sizeof(struct sockaddr_storage);
- short port_be;
- getsockname(sockfd, address, &len);
- if (address->sa_family == AF_INET)
- port_be = ((struct sockaddr_in*)address)->sin_port;
- else if (address->sa_family == AF_INET6)
- port_be = ((struct sockaddr_in6*)address)->sin6_port;
- else perror_exit("getsockname: bad family");
- dprintf(1, "%d\n", SWAP_BE16(port_be));
- // Return immediately if no -p and -Ll has arguments, so wrapper
- // script can use port number.
- if (CFG_TOYBOX_FORK && toys.optc && xfork()) goto cleanup;
- }
- do {
- child = 0;
- in1 = out2 = accept(sockfd, 0, 0);
- if (in1<0) perror_exit("accept");
- // We have a connection. Disarm timeout.
- set_alarm(0);
- if (toys.optc) {
- // Do we need a tty?
- // TODO nommu, and -t only affects server mode...? Only do -t with optc
- // if (CFG_TOYBOX_FORK && (toys.optflags&FLAG_t))
- // child = forkpty(&fdout, NULL, NULL, NULL);
- // else
- // Do we need to fork and/or redirect for exec?
- // TODO xpopen_both() here?
- if (FLAG(L)) NOEXIT(child = XVFORK());
- if (child) {
- close(in1);
- continue;
- }
- close(sockfd);
- dup2(in1, 0);
- dup2(in1, 1);
- if (FLAG(E)) dup2(in1, 2);
- if (in1>2) close(in1);
- xexec(toys.optargs);
- }
- pollinate(in1, in2, out1, out2, TT.W, TT.q);
- close(in1);
- } while (!FLAG(l));
- }
- }
- cleanup:
- if (CFG_TOYBOX_FREE) {
- close(in1);
- close(sockfd);
- }
- }
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