*
* Copyright (C) 2007 Denys Vlasenko.
*
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
/* Author's comments from nc 1.10:
* - source routing
* - multiple DNS checks
* Functionalty which is different from nc 1.10:
- * - Prog in '-e prog' can have prog's parameters and options.
+ * - PROG in '-e PROG' can have ARGS (and options).
* Because of this -e option must be last.
- * - nc doesn't redirect stderr to the network socket for the -e prog.
+//TODO: remove -e incompatibility?
+ * - we don't redirect stderr to the network socket for the -e PROG.
+ * (PROG can do it itself if needed, but sometimes it is NOT wanted!)
* - numeric addresses are printed in (), not [] (IPv6 looks better),
* port numbers are inside (): (1.2.3.4:5678)
* - network read errors are reported on verbose levels > 1
* (nc 1.10 treats them as EOF)
* - TCP connects from wrong ip/ports (if peer ip:port is specified
* on the command line, but accept() says that it came from different addr)
- * are closed, but nc doesn't exit - continues to listen/accept.
+ * are closed, but we don't exit - we continue to listen/accept.
*/
/* done in nc.c: #include "libbb.h" */
+//usage:#if ENABLE_NC_110_COMPAT
+//usage:
+//usage:#define nc_trivial_usage
+//usage: "[OPTIONS] HOST PORT - connect"
+//usage: IF_NC_SERVER("\n"
+//usage: "nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen")
+//usage:#define nc_full_usage "\n\n"
+//usage: "Options:"
+//usage: "\n -e PROG Run PROG after connect (must be last)"
+//usage: IF_NC_SERVER(
+//usage: "\n -l Listen mode, for inbound connects"
+//usage: )
+//usage: "\n -p PORT Local port"
+//usage: "\n -s ADDR Local address"
+//usage: "\n -w SEC Timeout for connects and final net reads"
+//usage: IF_NC_EXTRA(
+//usage: "\n -i SEC Delay interval for lines sent" /* ", ports scanned" */
+//usage: )
+//usage: "\n -n Don't do DNS resolution"
+//usage: "\n -u UDP mode"
+//usage: "\n -v Verbose"
+//usage: IF_NC_EXTRA(
+//usage: "\n -o FILE Hex dump traffic"
+//usage: "\n -z Zero-I/O mode (scanning)"
+//usage: )
+//usage:#endif
+
+/* "\n -r Randomize local and remote ports" */
+/* "\n -g gateway Source-routing hop point[s], up to 8" */
+/* "\n -G num Source-routing pointer: 4, 8, 12, ..." */
+/* "\nport numbers can be individual or ranges: lo-hi [inclusive]" */
+
+/* -e PROG can take ARGS too: "nc ... -e ls -l", but we don't document it
+ * in help text: nc 1.10 does not allow that. We don't want to entice
+ * users to use this incompatibility */
+
enum {
SLEAZE_PORT = 31337, /* for UDP-scan RTT trick, change if ya want */
BIGSIZ = 8192, /* big buffers */
/* Debug: squirt whatever message and sleep a bit so we can see it go by. */
/* Beware: writes to stdOUT... */
#if 0
-#define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush(stdout); sleep(1); } while (0)
+#define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush_all(); sleep(1); } while (0)
#else
#define Debug(...) do { } while (0)
#endif
/* dup2(0, 2); - do we *really* want this? NO!
* exec'ed prog can do it yourself, if needed */
execvp(proggie[0], proggie);
- bb_perror_msg_and_die("exec");
+ bb_perror_msg_and_die("can't execute '%s'", proggie[0]);
}
/* connect_w_timeout:
random unknown port is probably not very useful without "netstat". */
if (o_verbose) {
char *addr;
- rr = getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
- if (rr < 0)
- bb_perror_msg_and_die("getsockname after bind");
+ getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
+ //if (rr < 0)
+ // bb_perror_msg_and_die("getsockname after bind");
addr = xmalloc_sockaddr2dotted(&ouraddr->u.sa);
fprintf(stderr, "listening on %s ...\n", addr);
free(addr);
rr = accept(netfd, &remend.u.sa, &remend.len);
if (rr < 0)
bb_perror_msg_and_die("accept");
- if (themaddr && memcmp(&remend.u.sa, &themaddr->u.sa, remend.len) != 0) {
- /* nc 1.10 bails out instead, and its error message
- * is not suppressed by o_verbose */
- if (o_verbose) {
- char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
- bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
- free(remaddr);
+ if (themaddr) {
+ int sv_port, port, r;
+
+ sv_port = get_nport(&remend.u.sa); /* save */
+ port = get_nport(&themaddr->u.sa);
+ if (port == 0) {
+ /* "nc -nl -p LPORT RHOST" (w/o RPORT!):
+ * we should accept any remote port */
+ set_nport(&remend, 0); /* blot out remote port# */
+ }
+ r = memcmp(&remend.u.sa, &themaddr->u.sa, remend.len);
+ set_nport(&remend, sv_port); /* restore */
+ if (r != 0) {
+ /* nc 1.10 bails out instead, and its error message
+ * is not suppressed by o_verbose */
+ if (o_verbose) {
+ char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
+ bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
+ free(remaddr);
+ }
+ close(rr);
+ goto again;
}
- close(rr);
- goto again;
}
unarm();
} else
doing a listen-on-any on a multihomed machine. This allows one to
offer different services via different alias addresses, such as the
"virtual web site" hack. */
- rr = getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
- if (rr < 0)
- bb_perror_msg_and_die("getsockname after accept");
+ getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
+ //if (rr < 0)
+ // bb_perror_msg_and_die("getsockname after accept");
}
if (o_verbose) {
socklen_t x = sizeof(optbuf);
rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x);
- if (rr < 0)
- bb_perror_msg("getsockopt failed");
- else if (x) { /* we've got options, lessee em... */
+ if (rr >= 0 && x) { /* we've got options, lessee em... */
bin2hex(bigbuf_net, optbuf, x);
bigbuf_net[2*x] = '\0';
fprintf(stderr, "IP options: %s\n", bigbuf_net);
mobygrams are kinda fun and exercise the reassembler. */
if (rr <= 0) { /* at end, or fukt, or ... */
FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */
- close(0);
+ close(STDIN_FILENO);
+// Does it make sense to shutdown(net_fd, SHUT_WR)
+// to let other side know that we won't write anything anymore?
+// (and what about keeping compat if we do that?)
} else {
rzleft = rr;
zp = bigbuf_in;
/* main: now we pull it all together... */
int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int nc_main(int argc, char **argv)
+int nc_main(int argc UNUSED_PARAM, char **argv)
{
char *str_p, *str_s;
IF_NC_EXTRA(char *str_i, *str_o;)
while (*++proggie) {
if (strcmp(*proggie, "-e") == 0) {
*proggie = NULL;
- argc = proggie - argv;
proggie++;
goto e_found;
}
setsockopt_reuseaddr(netfd);
if (o_udpmode)
socket_want_pktinfo(netfd);
- xbind(netfd, &ouraddr->u.sa, ouraddr->len);
+ if (!ENABLE_FEATURE_UNIX_LOCAL
+ || o_listen
+ || ouraddr->u.sa.sa_family != AF_UNIX
+ ) {
+ xbind(netfd, &ouraddr->u.sa, ouraddr->len);
+ }
#if 0
setsockopt(netfd, SOL_SOCKET, SO_RCVBUF, &o_rcvbuf, sizeof o_rcvbuf);
setsockopt(netfd, SOL_SOCKET, SO_SNDBUF, &o_sndbuf, sizeof o_sndbuf);
} else {
/* Outbound connects. Now we're more picky about args... */
if (!themaddr)
- bb_error_msg_and_die("no destination");
+ bb_show_usage();
remend = *themaddr;
if (o_verbose)
projects / oweals / busybox.git / blobdiff