*
* 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: )
+//usage:#define nc_full_usage "\n\n"
+//usage: " -e PROG Run PROG after connect (must be last)"
+//usage: IF_NC_SERVER(
+//usage: "\n -l Listen mode, for inbound connects"
+//usage: "\n -lk With -e, provides persistent server"
+/* -ll does the same as -lk, but its our extension, while -k is BSD'd,
+ * presumably more widely known. Therefore we advertise it, not -ll.
+ * I would like to drop -ll support, but our "small" nc supports it,
+ * and Rob uses it.
+ */
+//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 */
unsigned wrote_out; /* total stdout bytes */
unsigned wrote_net; /* total net bytes */
#endif
+ char *proggie0saved;
/* ouraddr is never NULL and goes through three states as we progress:
1 - local address before bind (IP/port possibly zero)
2 - local address after bind (port is nonzero)
jmp_buf jbuf; /* timer crud */
- /* will malloc up the following globals: */
fd_set ding1; /* for select loop */
fd_set ding2;
char bigbuf_in[BIGSIZ]; /* data buffers */
/* Must match getopt32 call! */
enum {
- OPT_h = (1 << 0),
- OPT_n = (1 << 1),
- OPT_p = (1 << 2),
- OPT_s = (1 << 3),
- OPT_u = (1 << 4),
- OPT_v = (1 << 5),
- OPT_w = (1 << 6),
- OPT_l = (1 << 7) * ENABLE_NC_SERVER,
- OPT_i = (1 << (7+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
- OPT_o = (1 << (8+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
- OPT_z = (1 << (9+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
+ OPT_n = (1 << 0),
+ OPT_p = (1 << 1),
+ OPT_s = (1 << 2),
+ OPT_u = (1 << 3),
+ OPT_v = (1 << 4),
+ OPT_w = (1 << 5),
+ OPT_l = (1 << 6) * ENABLE_NC_SERVER,
+ OPT_k = (1 << 7) * ENABLE_NC_SERVER,
+ OPT_i = (1 << (7+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
+ OPT_o = (1 << (8+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
+ OPT_z = (1 << (9+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
};
#define o_nflag (option_mask32 & OPT_n)
#define o_udpmode (option_mask32 & OPT_u)
-#if ENABLE_NC_SERVER
-#define o_listen (option_mask32 & OPT_l)
-#else
-#define o_listen 0
-#endif
#if ENABLE_NC_EXTRA
#define o_ofile (option_mask32 & OPT_o)
#define o_zero (option_mask32 & OPT_z)
/* 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
}
/* timeout and other signal handling cruft */
-static void tmtravel(int sig ATTRIBUTE_UNUSED)
+static void tmtravel(int sig UNUSED_PARAM)
{
unarm();
longjmp(jbuf, 1);
that would be security-critical, which is why it's ifdefed out by default.
Use at your own hairy risk; if you leave shells lying around behind open
listening ports you deserve to lose!! */
-static int doexec(char **proggie) ATTRIBUTE_NORETURN;
+static int doexec(char **proggie) NORETURN;
static int doexec(char **proggie)
{
+ if (G.proggie0saved)
+ proggie[0] = G.proggie0saved;
xmove_fd(netfd, 0);
dup2(0, 1);
/* 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_EXECVP_or_die(proggie);
}
/* connect_w_timeout:
incoming and returns an open connection *from* someplace. If we were
given host/port args, any connections from elsewhere are rejected. This
in conjunction with local-address binding should limit things nicely... */
-static void dolisten(void)
+static void dolisten(int is_persistent, char **proggie)
{
int rr;
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);
xconnect(netfd, &remend.u.sa, ouraddr->len);
} else {
/* TCP */
+ another:
arm(o_wait); /* wrap this in a timer, too; 0 = forever */
if (setjmp(jbuf) == 0) {
again:
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.u.sa, 0); /* blot out remote port# */
+ }
+ r = memcmp(&remend.u.sa, &themaddr->u.sa, remend.len);
+ set_nport(&remend.u.sa, 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
bb_error_msg_and_die("timeout");
+
+ if (is_persistent && proggie) {
+ /* -l -k -e PROG */
+ signal(SIGCHLD, SIG_IGN); /* no zombies please */
+ if (xvfork() != 0) {
+ /* parent: go back and accept more connections */
+ close(rr);
+ goto another;
+ }
+ /* child */
+ signal(SIGCHLD, SIG_DFL);
+ }
+
xmove_fd(rr, netfd); /* dump the old socket, here's our new one */
/* find out what address the connection was *to* on our end, in case we're
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... */
- bin2hex(bigbuf_net, optbuf, x);
- bigbuf_net[2*x] = '\0';
+ if (rr >= 0 && x) { /* we've got options, lessee em... */
+ *bin2hex(bigbuf_net, optbuf, x) = '\0';
fprintf(stderr, "IP options: %s\n", bigbuf_net);
}
#endif
if (!o_nflag)
free(remhostname);
}
+
+ if (proggie)
+ doexec(proggie);
}
/* udptest:
us to hang forever, and hit it */
o_wait = 5; /* enough that we'll notice?? */
rr = xsocket(ouraddr->u.sa.sa_family, SOCK_STREAM, 0);
- set_nport(themaddr, htons(SLEAZE_PORT));
+ set_nport(&themaddr->u.sa, htons(SLEAZE_PORT));
connect_w_timeout(rr);
/* don't need to restore themaddr's port, it's not used anymore */
close(rr);
/* if we have a timeout AND stdin is closed AND we haven't heard anything
from the net during that time, assume it's dead and close it too. */
if (rr == 0) {
- if (!FD_ISSET(0, &ding1))
+ if (!FD_ISSET(STDIN_FILENO, &ding1))
netretry--; /* we actually try a coupla times. */
if (!netretry) {
if (o_verbose > 1) /* normally we don't care */
goto shovel;
/* okay, suck more stdin */
- if (FD_ISSET(0, &ding2)) { /* stdin: ding! */
- rr = read(0, bigbuf_in, BIGSIZ);
+ if (FD_ISSET(STDIN_FILENO, &ding2)) { /* stdin: ding! */
+ rr = read(STDIN_FILENO, bigbuf_in, BIGSIZ);
/* Considered making reads here smaller for UDP mode, but 8192-byte
mobygrams are kinda fun and exercise the reassembler. */
if (rr <= 0) { /* at end, or fukt, or ... */
- FD_CLR(0, &ding1); /* disable and close stdin */
- close(0);
+ FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */
+ 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;
return 1;
}
if (rnleft) {
- rr = write(1, np, rnleft);
+ rr = write(STDOUT_FILENO, np, rnleft);
if (rr > 0) {
if (o_ofile) /* log the stdout */
oprint('<', (unsigned char *)np, rr);
/* 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;
- USE_NC_EXTRA(char *str_i, *str_o;)
- char *themdotted = themdotted; /* gcc */
+ IF_NC_EXTRA(char *str_i, *str_o;)
+ char *themdotted = themdotted; /* for compiler */
char **proggie;
int x;
+ unsigned cnt_l = 0;
unsigned o_lport = 0;
INIT_G();
while (*++proggie) {
if (strcmp(*proggie, "-e") == 0) {
*proggie = NULL;
- argc = proggie - argv;
proggie++;
goto e_found;
}
+ /* -<other_opts>e PROG [ARGS] ? */
+ /* (aboriginal linux uses this form) */
+ if (proggie[0][0] == '-') {
+ char *optpos = *proggie + 1;
+ /* Skip all valid opts w/o params */
+ optpos = optpos + strspn(optpos, "nuv"IF_NC_SERVER("lk")IF_NC_EXTRA("z"));
+ if (*optpos == 'e' && !optpos[1]) {
+ *optpos = '\0';
+ proggie++;
+ G.proggie0saved = *proggie;
+ *proggie = NULL; /* terminate argv for getopt32 */
+ goto e_found;
+ }
+ }
}
proggie = NULL;
e_found:
// -g -G -t -r deleted, unimplemented -a deleted too
- opt_complementary = "?2:vv:w+"; /* max 2 params; -v is a counter; -w N */
- getopt32(argv, "hnp:s:uvw:" USE_NC_SERVER("l")
- USE_NC_EXTRA("i:o:z"),
+ opt_complementary = "?2:vv:ll:w+"; /* max 2 params; -v and -l are counters; -w N */
+ getopt32(argv, "np:s:uvw:" IF_NC_SERVER("lk")
+ IF_NC_EXTRA("i:o:z"),
&str_p, &str_s, &o_wait
- USE_NC_EXTRA(, &str_i, &str_o, &o_verbose));
+ IF_NC_EXTRA(, &str_i, &str_o), &o_verbose IF_NC_SERVER(, &cnt_l));
argv += optind;
#if ENABLE_NC_EXTRA
if (option_mask32 & OPT_i) /* line-interval time */
o_interval = xatou_range(str_i, 1, 0xffff);
#endif
+#if ENABLE_NC_SERVER
//if (option_mask32 & OPT_l) /* listen mode */
+ if (option_mask32 & OPT_k) /* persistent server mode */
+ cnt_l = 2;
+#endif
//if (option_mask32 & OPT_n) /* numeric-only, no DNS lookups */
//if (option_mask32 & OPT_o) /* hexdump log */
if (option_mask32 & OPT_p) { /* local source port */
(themaddr ? themaddr->u.sa.sa_family : AF_UNSPEC),
x);
if (o_lport)
- set_nport(ouraddr, htons(o_lport));
+ set_nport(&ouraddr->u.sa, htons(o_lport));
}
xmove_fd(x, netfd);
setsockopt_reuseaddr(netfd);
if (o_udpmode)
socket_want_pktinfo(netfd);
- xbind(netfd, &ouraddr->u.sa, ouraddr->len);
+ if (!ENABLE_FEATURE_UNIX_LOCAL
+ || cnt_l != 0 /* 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);
}
#endif
- FD_SET(0, &ding1); /* stdin *is* initially open */
+ FD_SET(STDIN_FILENO, &ding1); /* stdin *is* initially open */
if (proggie) {
close(0); /* won't need stdin */
option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd);
#endif
- if (o_listen) {
- dolisten();
+ if (cnt_l != 0) {
+ dolisten((cnt_l - 1), proggie);
/* dolisten does its own connect reporting */
- if (proggie) /* -e given? */
- doexec(proggie);
x = readwrite(); /* it even works with UDP! */
} 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