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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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