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Denis Vlasenko29fe7262007-04-05 20:26:28 +00001/* Based on netcat 1.10 RELEASE 960320 written by hobbit@avian.org.
2 * Released into public domain by the author.
3 *
Denis Vlasenko7cff01e2008-02-02 16:23:43 +00004 * Copyright (C) 2007 Denys Vlasenko.
Denis Vlasenko29fe7262007-04-05 20:26:28 +00005 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02006 * Licensed under GPLv2, see file LICENSE in this source tree.
Denis Vlasenko29fe7262007-04-05 20:26:28 +00007 */
8
9/* Author's comments from nc 1.10:
10 * =====================
11 * Netcat is entirely my own creation, although plenty of other code was used as
12 * examples. It is freely given away to the Internet community in the hope that
13 * it will be useful, with no restrictions except giving credit where it is due.
14 * No GPLs, Berkeley copyrights or any of that nonsense. The author assumes NO
15 * responsibility for how anyone uses it. If netcat makes you rich somehow and
16 * you're feeling generous, mail me a check. If you are affiliated in any way
17 * with Microsoft Network, get a life. Always ski in control. Comments,
18 * questions, and patches to hobbit@avian.org.
19 * ...
20 * Netcat and the associated package is a product of Avian Research, and is freely
21 * available in full source form with no restrictions save an obligation to give
22 * credit where due.
23 * ...
24 * A damn useful little "backend" utility begun 950915 or thereabouts,
25 * as *Hobbit*'s first real stab at some sockets programming. Something that
26 * should have and indeed may have existed ten years ago, but never became a
27 * standard Unix utility. IMHO, "nc" could take its place right next to cat,
28 * cp, rm, mv, dd, ls, and all those other cryptic and Unix-like things.
29 * =====================
30 *
31 * Much of author's comments are still retained in the code.
32 *
33 * Functionality removed (rationale):
34 * - miltiple-port ranges, randomized port scanning (use nmap)
35 * - telnet support (use telnet)
36 * - source routing
37 * - multiple DNS checks
38 * Functionalty which is different from nc 1.10:
Denys Vlasenko7d1201c2010-06-28 04:17:06 +020039 * - PROG in '-e PROG' can have ARGS (and options).
Denis Vlasenko29fe7262007-04-05 20:26:28 +000040 * Because of this -e option must be last.
Denys Vlasenko7d1201c2010-06-28 04:17:06 +020041//TODO: remove -e incompatibility?
42 * - we don't redirect stderr to the network socket for the -e PROG.
43 * (PROG can do it itself if needed, but sometimes it is NOT wanted!)
Denis Vlasenko19507f02007-04-06 10:41:05 +000044 * - numeric addresses are printed in (), not [] (IPv6 looks better),
45 * port numbers are inside (): (1.2.3.4:5678)
46 * - network read errors are reported on verbose levels > 1
47 * (nc 1.10 treats them as EOF)
48 * - TCP connects from wrong ip/ports (if peer ip:port is specified
49 * on the command line, but accept() says that it came from different addr)
Denys Vlasenko7d1201c2010-06-28 04:17:06 +020050 * are closed, but we don't exit - we continue to listen/accept.
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +020051 * Since bbox 1.22:
52 * - nc exits when _both_ stdin and network are closed.
53 * This makes these two commands:
54 * echo "Yes" | nc 127.0.0.1 1234
55 * echo "no" | nc -lp 1234
56 * exchange their data _and exit_ instead of being stuck.
Denis Vlasenko29fe7262007-04-05 20:26:28 +000057 */
58
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000059/* done in nc.c: #include "libbb.h" */
Denis Vlasenko29fe7262007-04-05 20:26:28 +000060
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020061//usage:#if ENABLE_NC_110_COMPAT
62//usage:
63//usage:#define nc_trivial_usage
64//usage: "[OPTIONS] HOST PORT - connect"
65//usage: IF_NC_SERVER("\n"
Denys Vlasenko3b2acb72010-10-09 21:10:32 +020066//usage: "nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen"
67//usage: )
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020068//usage:#define nc_full_usage "\n\n"
Denys Vlasenko66426762011-06-05 03:58:28 +020069//usage: " -e PROG Run PROG after connect (must be last)"
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020070//usage: IF_NC_SERVER(
71//usage: "\n -l Listen mode, for inbound connects"
Denys Vlasenkode6f1482013-02-28 12:20:06 +010072//usage: "\n -lk With -e, provides persistent server"
73/* -ll does the same as -lk, but its our extension, while -k is BSD'd,
74 * presumably more widely known. Therefore we advertise it, not -ll.
75 * I would like to drop -ll support, but our "small" nc supports it,
76 * and Rob uses it.
77 */
Denys Vlasenko77cc2c52010-06-27 04:22:02 +020078//usage: )
79//usage: "\n -p PORT Local port"
80//usage: "\n -s ADDR Local address"
81//usage: "\n -w SEC Timeout for connects and final net reads"
82//usage: IF_NC_EXTRA(
83//usage: "\n -i SEC Delay interval for lines sent" /* ", ports scanned" */
84//usage: )
85//usage: "\n -n Don't do DNS resolution"
86//usage: "\n -u UDP mode"
87//usage: "\n -v Verbose"
88//usage: IF_NC_EXTRA(
89//usage: "\n -o FILE Hex dump traffic"
90//usage: "\n -z Zero-I/O mode (scanning)"
91//usage: )
92//usage:#endif
93
94/* "\n -r Randomize local and remote ports" */
95/* "\n -g gateway Source-routing hop point[s], up to 8" */
96/* "\n -G num Source-routing pointer: 4, 8, 12, ..." */
97/* "\nport numbers can be individual or ranges: lo-hi [inclusive]" */
98
99/* -e PROG can take ARGS too: "nc ... -e ls -l", but we don't document it
100 * in help text: nc 1.10 does not allow that. We don't want to entice
101 * users to use this incompatibility */
102
Denis Vlasenko19507f02007-04-06 10:41:05 +0000103enum {
104 SLEAZE_PORT = 31337, /* for UDP-scan RTT trick, change if ya want */
105 BIGSIZ = 8192, /* big buffers */
106
107 netfd = 3,
108 ofd = 4,
109};
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000110
111struct globals {
Denis Vlasenko19507f02007-04-06 10:41:05 +0000112 /* global cmd flags: */
113 unsigned o_verbose;
114 unsigned o_wait;
115#if ENABLE_NC_EXTRA
116 unsigned o_interval;
117#endif
118
119 /*int netfd;*/
120 /*int ofd;*/ /* hexdump output fd */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000121#if ENABLE_LFS
122#define SENT_N_RECV_M "sent %llu, rcvd %llu\n"
123 unsigned long long wrote_out; /* total stdout bytes */
124 unsigned long long wrote_net; /* total net bytes */
125#else
Denis Vlasenko19507f02007-04-06 10:41:05 +0000126#define SENT_N_RECV_M "sent %u, rcvd %u\n"
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000127 unsigned wrote_out; /* total stdout bytes */
128 unsigned wrote_net; /* total net bytes */
129#endif
Denys Vlasenko5e896482012-03-19 01:17:36 +0100130 char *proggie0saved;
Bernhard Reutner-Fischera985d302008-02-11 11:44:38 +0000131 /* ouraddr is never NULL and goes through three states as we progress:
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000132 1 - local address before bind (IP/port possibly zero)
133 2 - local address after bind (port is nonzero)
134 3 - local address after connect??/recv/accept (IP and port are nonzero) */
135 struct len_and_sockaddr *ouraddr;
136 /* themaddr is NULL if no peer hostname[:port] specified on command line */
137 struct len_and_sockaddr *themaddr;
138 /* remend is set after connect/recv/accept to the actual ip:port of peer */
139 struct len_and_sockaddr remend;
140
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000141 jmp_buf jbuf; /* timer crud */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000142
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000143 char bigbuf_in[BIGSIZ]; /* data buffers */
144 char bigbuf_net[BIGSIZ];
145};
146
147#define G (*ptr_to_globals)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000148#define wrote_out (G.wrote_out )
149#define wrote_net (G.wrote_net )
150#define ouraddr (G.ouraddr )
151#define themaddr (G.themaddr )
152#define remend (G.remend )
153#define jbuf (G.jbuf )
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000154#define bigbuf_in (G.bigbuf_in )
155#define bigbuf_net (G.bigbuf_net)
156#define o_verbose (G.o_verbose )
157#define o_wait (G.o_wait )
158#if ENABLE_NC_EXTRA
159#define o_interval (G.o_interval)
160#else
161#define o_interval 0
162#endif
Denis Vlasenko574f2f42008-02-27 18:41:59 +0000163#define INIT_G() do { \
164 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
165} while (0)
166
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000167
168/* Must match getopt32 call! */
169enum {
Denys Vlasenko5e896482012-03-19 01:17:36 +0100170 OPT_n = (1 << 0),
171 OPT_p = (1 << 1),
172 OPT_s = (1 << 2),
173 OPT_u = (1 << 3),
174 OPT_v = (1 << 4),
175 OPT_w = (1 << 5),
176 OPT_l = (1 << 6) * ENABLE_NC_SERVER,
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100177 OPT_k = (1 << 7) * ENABLE_NC_SERVER,
Denys Vlasenkoc4728982014-02-26 13:58:59 +0100178 OPT_i = (1 << (6+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
179 OPT_o = (1 << (7+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
180 OPT_z = (1 << (8+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000181};
182
183#define o_nflag (option_mask32 & OPT_n)
184#define o_udpmode (option_mask32 & OPT_u)
Denis Vlasenko19507f02007-04-06 10:41:05 +0000185#if ENABLE_NC_EXTRA
186#define o_ofile (option_mask32 & OPT_o)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000187#define o_zero (option_mask32 & OPT_z)
188#else
Denis Vlasenko19507f02007-04-06 10:41:05 +0000189#define o_ofile 0
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000190#define o_zero 0
191#endif
192
Denis Vlasenko19507f02007-04-06 10:41:05 +0000193/* Debug: squirt whatever message and sleep a bit so we can see it go by. */
194/* Beware: writes to stdOUT... */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000195#if 0
Denys Vlasenko8131eea2009-11-02 14:19:51 +0100196#define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush_all(); sleep(1); } while (0)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000197#else
Denis Vlasenko51742f42007-04-12 00:32:05 +0000198#define Debug(...) do { } while (0)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000199#endif
200
Denis Vlasenko51742f42007-04-12 00:32:05 +0000201#define holler_error(...) do { if (o_verbose) bb_error_msg(__VA_ARGS__); } while (0)
202#define holler_perror(...) do { if (o_verbose) bb_perror_msg(__VA_ARGS__); } while (0)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000203
204/* catch: no-brainer interrupt handler */
205static void catch(int sig)
206{
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000207 if (o_verbose > 1) /* normally we don't care */
208 fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);
209 fprintf(stderr, "punt!\n");
Denis Vlasenko400d8bb2008-02-24 13:36:01 +0000210 kill_myself_with_sig(sig);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000211}
212
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000213/* unarm */
214static void unarm(void)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000215{
216 signal(SIGALRM, SIG_IGN);
217 alarm(0);
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000218}
219
220/* timeout and other signal handling cruft */
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000221static void tmtravel(int sig UNUSED_PARAM)
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000222{
223 unarm();
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000224 longjmp(jbuf, 1);
225}
226
227/* arm: set the timer. */
228static void arm(unsigned secs)
229{
230 signal(SIGALRM, tmtravel);
231 alarm(secs);
232}
233
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000234/* findline:
235 find the next newline in a buffer; return inclusive size of that "line",
236 or the entire buffer size, so the caller knows how much to then write().
237 Not distinguishing \n vs \r\n for the nonce; it just works as is... */
238static unsigned findline(char *buf, unsigned siz)
239{
240 char * p;
241 int x;
242 if (!buf) /* various sanity checks... */
243 return 0;
244 if (siz > BIGSIZ)
245 return 0;
246 x = siz;
247 for (p = buf; x > 0; x--) {
248 if (*p == '\n') {
249 x = (int) (p - buf);
250 x++; /* 'sokay if it points just past the end! */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000251Debug("findline returning %d", x);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000252 return x;
253 }
254 p++;
255 } /* for */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000256Debug("findline returning whole thing: %d", siz);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000257 return siz;
258} /* findline */
259
260/* doexec:
261 fiddle all the file descriptors around, and hand off to another prog. Sort
262 of like a one-off "poor man's inetd". This is the only section of code
263 that would be security-critical, which is why it's ifdefed out by default.
264 Use at your own hairy risk; if you leave shells lying around behind open
265 listening ports you deserve to lose!! */
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000266static int doexec(char **proggie) NORETURN;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000267static int doexec(char **proggie)
268{
Denys Vlasenko5e896482012-03-19 01:17:36 +0100269 if (G.proggie0saved)
270 proggie[0] = G.proggie0saved;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000271 xmove_fd(netfd, 0);
272 dup2(0, 1);
273 /* dup2(0, 2); - do we *really* want this? NO!
274 * exec'ed prog can do it yourself, if needed */
Denys Vlasenko1c31e9e2010-11-28 04:34:09 +0100275 BB_EXECVP_or_die(proggie);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000276}
277
278/* connect_w_timeout:
279 return an fd for one of
280 an open outbound TCP connection, a UDP stub-socket thingie, or
281 an unconnected TCP or UDP socket to listen on.
282 Examines various global o_blah flags to figure out what to do.
283 lad can be NULL, then socket is not bound to any local ip[:port] */
284static int connect_w_timeout(int fd)
285{
286 int rr;
287
288 /* wrap connect inside a timer, and hit it */
289 arm(o_wait);
290 if (setjmp(jbuf) == 0) {
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000291 rr = connect(fd, &themaddr->u.sa, themaddr->len);
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000292 unarm();
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000293 } else { /* setjmp: connect failed... */
294 rr = -1;
295 errno = ETIMEDOUT; /* fake it */
296 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000297 return rr;
298}
299
300/* dolisten:
301 listens for
302 incoming and returns an open connection *from* someplace. If we were
303 given host/port args, any connections from elsewhere are rejected. This
304 in conjunction with local-address binding should limit things nicely... */
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100305static void dolisten(int is_persistent, char **proggie)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000306{
307 int rr;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000308
309 if (!o_udpmode)
310 xlisten(netfd, 1); /* TCP: gotta listen() before we can get */
311
312 /* Various things that follow temporarily trash bigbuf_net, which might contain
313 a copy of any recvfrom()ed packet, but we'll read() another copy later. */
314
315 /* I can't believe I have to do all this to get my own goddamn bound address
316 and port number. It should just get filled in during bind() or something.
317 All this is only useful if we didn't say -p for listening, since if we
318 said -p we *know* what port we're listening on. At any rate we won't bother
319 with it all unless we wanted to see it, although listening quietly on a
320 random unknown port is probably not very useful without "netstat". */
321 if (o_verbose) {
322 char *addr;
Denis Vlasenkoa771e7c2009-04-21 23:48:38 +0000323 getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
324 //if (rr < 0)
325 // bb_perror_msg_and_die("getsockname after bind");
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000326 addr = xmalloc_sockaddr2dotted(&ouraddr->u.sa);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000327 fprintf(stderr, "listening on %s ...\n", addr);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000328 free(addr);
329 }
330
331 if (o_udpmode) {
332 /* UDP is a speeeeecial case -- we have to do I/O *and* get the calling
333 party's particulars all at once, listen() and accept() don't apply.
334 At least in the BSD universe, however, recvfrom/PEEK is enough to tell
335 us something came in, and we can set things up so straight read/write
336 actually does work after all. Yow. YMMV on strange platforms! */
337
338 /* I'm not completely clear on how this works -- BSD seems to make UDP
339 just magically work in a connect()ed context, but we'll undoubtedly run
340 into systems this deal doesn't work on. For now, we apparently have to
341 issue a connect() on our just-tickled socket so we can write() back.
342 Again, why the fuck doesn't it just get filled in and taken care of?!
343 This hack is anything but optimal. Basically, if you want your listener
344 to also be able to send data back, you need this connect() line, which
345 also has the side effect that now anything from a different source or even a
346 different port on the other end won't show up and will cause ICMP errors.
347 I guess that's what they meant by "connect".
348 Let's try to remember what the "U" is *really* for, eh? */
349
350 /* If peer address is specified, connect to it */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000351 remend.len = LSA_SIZEOF_SA;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000352 if (themaddr) {
353 remend = *themaddr;
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000354 xconnect(netfd, &themaddr->u.sa, themaddr->len);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000355 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000356 /* peek first packet and remember peer addr */
357 arm(o_wait); /* might as well timeout this, too */
358 if (setjmp(jbuf) == 0) { /* do timeout for initial connect */
359 /* (*ouraddr) is prefilled with "default" address */
360 /* and here we block... */
361 rr = recv_from_to(netfd, NULL, 0, MSG_PEEK, /*was bigbuf_net, BIGSIZ*/
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000362 &remend.u.sa, &ouraddr->u.sa, ouraddr->len);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000363 if (rr < 0)
364 bb_perror_msg_and_die("recvfrom");
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000365 unarm();
Denis Vlasenko19507f02007-04-06 10:41:05 +0000366 } else
367 bb_error_msg_and_die("timeout");
Denis Vlasenko19507f02007-04-06 10:41:05 +0000368/* Now we learned *to which IP* peer has connected, and we want to anchor
369our socket on it, so that our outbound packets will have correct local IP.
370Unfortunately, bind() on already bound socket will fail now (EINVAL):
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000371 xbind(netfd, &ouraddr->u.sa, ouraddr->len);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000372Need to read the packet, save data, close this socket and
373create new one, and bind() it. TODO */
374 if (!themaddr)
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000375 xconnect(netfd, &remend.u.sa, ouraddr->len);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000376 } else {
377 /* TCP */
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100378 another:
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000379 arm(o_wait); /* wrap this in a timer, too; 0 = forever */
380 if (setjmp(jbuf) == 0) {
Denis Vlasenko19507f02007-04-06 10:41:05 +0000381 again:
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000382 remend.len = LSA_SIZEOF_SA;
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000383 rr = accept(netfd, &remend.u.sa, &remend.len);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000384 if (rr < 0)
385 bb_perror_msg_and_die("accept");
Denys Vlasenko866710a2010-01-08 16:09:45 +0100386 if (themaddr) {
387 int sv_port, port, r;
388
389 sv_port = get_nport(&remend.u.sa); /* save */
390 port = get_nport(&themaddr->u.sa);
391 if (port == 0) {
392 /* "nc -nl -p LPORT RHOST" (w/o RPORT!):
393 * we should accept any remote port */
Denys Vlasenkoca183112011-04-07 17:52:20 +0200394 set_nport(&remend.u.sa, 0); /* blot out remote port# */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000395 }
Denys Vlasenko866710a2010-01-08 16:09:45 +0100396 r = memcmp(&remend.u.sa, &themaddr->u.sa, remend.len);
Denys Vlasenkoca183112011-04-07 17:52:20 +0200397 set_nport(&remend.u.sa, sv_port); /* restore */
Denys Vlasenko866710a2010-01-08 16:09:45 +0100398 if (r != 0) {
399 /* nc 1.10 bails out instead, and its error message
400 * is not suppressed by o_verbose */
401 if (o_verbose) {
402 char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
403 bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
404 free(remaddr);
405 }
406 close(rr);
407 goto again;
408 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000409 }
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000410 unarm();
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000411 } else
412 bb_error_msg_and_die("timeout");
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100413
414 if (is_persistent && proggie) {
415 /* -l -k -e PROG */
416 signal(SIGCHLD, SIG_IGN); /* no zombies please */
417 if (xvfork() != 0) {
418 /* parent: go back and accept more connections */
419 close(rr);
420 goto another;
421 }
422 /* child */
423 signal(SIGCHLD, SIG_DFL);
424 }
425
Denis Vlasenko19507f02007-04-06 10:41:05 +0000426 xmove_fd(rr, netfd); /* dump the old socket, here's our new one */
427 /* find out what address the connection was *to* on our end, in case we're
428 doing a listen-on-any on a multihomed machine. This allows one to
429 offer different services via different alias addresses, such as the
430 "virtual web site" hack. */
Denis Vlasenkoa771e7c2009-04-21 23:48:38 +0000431 getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
432 //if (rr < 0)
433 // bb_perror_msg_and_die("getsockname after accept");
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000434 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000435
436 if (o_verbose) {
437 char *lcladdr, *remaddr, *remhostname;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000438
439#if ENABLE_NC_EXTRA && defined(IP_OPTIONS)
440 /* If we can, look for any IP options. Useful for testing the receiving end of
441 such things, and is a good exercise in dealing with it. We do this before
442 the connect message, to ensure that the connect msg is uniformly the LAST
443 thing to emerge after all the intervening crud. Doesn't work for UDP on
444 any machines I've tested, but feel free to surprise me. */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000445 char optbuf[40];
Denis Vlasenkoc4f12f52008-05-12 14:35:56 +0000446 socklen_t x = sizeof(optbuf);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000447
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000448 rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x);
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000449 if (rr >= 0 && x) { /* we've got options, lessee em... */
Denys Vlasenko2ea73b52011-10-19 22:31:01 +0200450 *bin2hex(bigbuf_net, optbuf, x) = '\0';
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000451 fprintf(stderr, "IP options: %s\n", bigbuf_net);
452 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000453#endif
454
455 /* now check out who it is. We don't care about mismatched DNS names here,
456 but any ADDR and PORT we specified had better fucking well match the caller.
457 Converting from addr to inet_ntoa and back again is a bit of a kludge, but
458 gethostpoop wants a string and there's much gnarlier code out there already,
459 so I don't feel bad.
460 The *real* question is why BFD sockets wasn't designed to allow listens for
461 connections *from* specific hosts/ports, instead of requiring the caller to
462 accept the connection and then reject undesireable ones by closing.
463 In other words, we need a TCP MSG_PEEK. */
464 /* bbox: removed most of it */
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000465 lcladdr = xmalloc_sockaddr2dotted(&ouraddr->u.sa);
466 remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
467 remhostname = o_nflag ? remaddr : xmalloc_sockaddr2host(&remend.u.sa);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000468 fprintf(stderr, "connect to %s from %s (%s)\n",
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000469 lcladdr, remhostname, remaddr);
470 free(lcladdr);
471 free(remaddr);
472 if (!o_nflag)
473 free(remhostname);
474 }
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100475
476 if (proggie)
477 doexec(proggie);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000478}
479
480/* udptest:
481 fire a couple of packets at a UDP target port, just to see if it's really
482 there. On BSD kernels, ICMP host/port-unreachable errors get delivered to
483 our socket as ECONNREFUSED write errors. On SV kernels, we lose; we'll have
484 to collect and analyze raw ICMP ourselves a la satan's probe_udp_ports
485 backend. Guess where one could swipe the appropriate code from...
486
487 Use the time delay between writes if given, otherwise use the "tcp ping"
488 trick for getting the RTT. [I got that idea from pluvius, and warped it.]
489 Return either the original fd, or clean up and return -1. */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000490#if ENABLE_NC_EXTRA
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000491static int udptest(void)
492{
493 int rr;
494
495 rr = write(netfd, bigbuf_in, 1);
496 if (rr != 1)
497 bb_perror_msg("udptest first write");
498
499 if (o_wait)
Denis Vlasenko19507f02007-04-06 10:41:05 +0000500 sleep(o_wait); // can be interrupted! while (t) nanosleep(&t)?
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000501 else {
502 /* use the tcp-ping trick: try connecting to a normally refused port, which
503 causes us to block for the time that SYN gets there and RST gets back.
504 Not completely reliable, but it *does* mostly work. */
505 /* Set a temporary connect timeout, so packet filtration doesnt cause
506 us to hang forever, and hit it */
507 o_wait = 5; /* enough that we'll notice?? */
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000508 rr = xsocket(ouraddr->u.sa.sa_family, SOCK_STREAM, 0);
Denys Vlasenkoca183112011-04-07 17:52:20 +0200509 set_nport(&themaddr->u.sa, htons(SLEAZE_PORT));
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000510 connect_w_timeout(rr);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000511 /* don't need to restore themaddr's port, it's not used anymore */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000512 close(rr);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000513 o_wait = 0; /* restore */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000514 }
515
516 rr = write(netfd, bigbuf_in, 1);
517 return (rr != 1); /* if rr == 1, return 0 (success) */
518}
Denis Vlasenko19507f02007-04-06 10:41:05 +0000519#else
520int udptest(void);
521#endif
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000522
523/* oprint:
524 Hexdump bytes shoveled either way to a running logfile, in the format:
525 D offset - - - - --- 16 bytes --- - - - - # .... ascii .....
526 where "which" sets the direction indicator, D:
527 0 -- sent to network, or ">"
528 1 -- rcvd and printed to stdout, or "<"
529 and "buf" and "n" are data-block and length. If the current block generates
530 a partial line, so be it; we *want* that lockstep indication of who sent
531 what when. Adapted from dgaudet's original example -- but must be ripping
532 *fast*, since we don't want to be too disk-bound... */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000533#if ENABLE_NC_EXTRA
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000534static void oprint(int direction, unsigned char *p, unsigned bc)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000535{
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000536 unsigned obc; /* current "global" offset */
537 unsigned x;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000538 unsigned char *op; /* out hexdump ptr */
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000539 unsigned char *ap; /* out asc-dump ptr */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000540 unsigned char stage[100];
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000541
Denis Vlasenko19507f02007-04-06 10:41:05 +0000542 if (bc == 0)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000543 return;
544
Denis Vlasenko19507f02007-04-06 10:41:05 +0000545 obc = wrote_net; /* use the globals! */
546 if (direction == '<')
547 obc = wrote_out;
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000548 stage[0] = direction;
549 stage[59] = '#'; /* preload separator */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000550 stage[60] = ' ';
551
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000552 do { /* for chunk-o-data ... */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000553 x = 16;
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000554 if (bc < 16) {
555 /* memset(&stage[bc*3 + 11], ' ', 16*3 - bc*3); */
556 memset(&stage[11], ' ', 16*3);
557 x = bc;
558 }
Denis Vlasenkoc4f12f52008-05-12 14:35:56 +0000559 sprintf((char *)&stage[1], " %8.8x ", obc); /* xxx: still slow? */
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000560 bc -= x; /* fix current count */
561 obc += x; /* fix current offset */
562 op = &stage[11]; /* where hex starts */
563 ap = &stage[61]; /* where ascii starts */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000564
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000565 do { /* for line of dump, however long ... */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000566 *op++ = 0x20 | bb_hexdigits_upcase[*p >> 4];
567 *op++ = 0x20 | bb_hexdigits_upcase[*p & 0x0f];
568 *op++ = ' ';
569 if ((*p > 31) && (*p < 127))
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000570 *ap = *p; /* printing */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000571 else
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000572 *ap = '.'; /* nonprinting, loose def */
573 ap++;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000574 p++;
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000575 } while (--x);
576 *ap++ = '\n'; /* finish the line */
577 xwrite(ofd, stage, ap - stage);
578 } while (bc);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000579}
Denis Vlasenko19507f02007-04-06 10:41:05 +0000580#else
Denis Vlasenko828e2a92007-07-13 12:37:31 +0000581void oprint(int direction, unsigned char *p, unsigned bc);
Denis Vlasenko19507f02007-04-06 10:41:05 +0000582#endif
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000583
584/* readwrite:
585 handle stdin/stdout/network I/O. Bwahaha!! -- the select loop from hell.
586 In this instance, return what might become our exit status. */
587static int readwrite(void)
588{
589 int rr;
590 char *zp = zp; /* gcc */ /* stdin buf ptr */
591 char *np = np; /* net-in buf ptr */
592 unsigned rzleft;
593 unsigned rnleft;
594 unsigned netretry; /* net-read retry counter */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200595 unsigned fds_open;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000596
597 /* if you don't have all this FD_* macro hair in sys/types.h, you'll have to
598 either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200599 fd_set ding1; /* for select loop */
600 fd_set ding2;
601 FD_ZERO(&ding1);
602 FD_SET(netfd, &ding1);
603 FD_SET(STDIN_FILENO, &ding1);
604 fds_open = 2;
605
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000606 netretry = 2;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000607 rzleft = rnleft = 0;
608 if (o_interval)
609 sleep(o_interval); /* pause *before* sending stuff, too */
610
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000611 /* and now the big ol' select shoveling loop ... */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200612 /* nc 1.10 has "while (FD_ISSET(netfd)" here */
613 while (fds_open) {
Denys Vlasenkofd3ac962013-07-28 22:24:51 +0200614 unsigned wretry = 8200; /* net-write sanity counter */
615
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000616 ding2 = ding1; /* FD_COPY ain't portable... */
617 /* some systems, notably linux, crap into their select timers on return, so
618 we create a expendable copy and give *that* to select. */
619 if (o_wait) {
620 struct timeval tmp_timer;
621 tmp_timer.tv_sec = o_wait;
622 tmp_timer.tv_usec = 0;
Denis Vlasenko19507f02007-04-06 10:41:05 +0000623 /* highest possible fd is netfd (3) */
624 rr = select(netfd+1, &ding2, NULL, NULL, &tmp_timer);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000625 } else
Denis Vlasenko19507f02007-04-06 10:41:05 +0000626 rr = select(netfd+1, &ding2, NULL, NULL, NULL);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000627 if (rr < 0 && errno != EINTR) { /* might have gotten ^Zed, etc */
628 holler_perror("select");
629 close(netfd);
630 return 1;
631 }
632 /* if we have a timeout AND stdin is closed AND we haven't heard anything
633 from the net during that time, assume it's dead and close it too. */
634 if (rr == 0) {
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200635 if (!FD_ISSET(STDIN_FILENO, &ding1)) {
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000636 netretry--; /* we actually try a coupla times. */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200637 if (!netretry) {
638 if (o_verbose > 1) /* normally we don't care */
639 fprintf(stderr, "net timeout\n");
Denys Vlasenkofd3ac962013-07-28 22:24:51 +0200640 /*close(netfd); - redundant, exit will do it */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200641 return 0; /* not an error! */
642 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000643 }
644 } /* select timeout */
645 /* xxx: should we check the exception fds too? The read fds seem to give
646 us the right info, and none of the examples I found bothered. */
647
648 /* Ding!! Something arrived, go check all the incoming hoppers, net first */
649 if (FD_ISSET(netfd, &ding2)) { /* net: ding! */
650 rr = read(netfd, bigbuf_net, BIGSIZ);
651 if (rr <= 0) {
Denis Vlasenko19507f02007-04-06 10:41:05 +0000652 if (rr < 0 && o_verbose > 1) {
653 /* nc 1.10 doesn't do this */
654 bb_perror_msg("net read");
655 }
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200656 FD_CLR(netfd, &ding1); /* net closed */
657 fds_open--;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000658 rzleft = 0; /* can't write anymore: broken pipe */
659 } else {
660 rnleft = rr;
661 np = bigbuf_net;
662 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000663Debug("got %d from the net, errno %d", rr, errno);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000664 } /* net:ding */
665
666 /* if we're in "slowly" mode there's probably still stuff in the stdin
667 buffer, so don't read unless we really need MORE INPUT! MORE INPUT! */
668 if (rzleft)
669 goto shovel;
670
671 /* okay, suck more stdin */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000672 if (FD_ISSET(STDIN_FILENO, &ding2)) { /* stdin: ding! */
673 rr = read(STDIN_FILENO, bigbuf_in, BIGSIZ);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000674 /* Considered making reads here smaller for UDP mode, but 8192-byte
675 mobygrams are kinda fun and exercise the reassembler. */
676 if (rr <= 0) { /* at end, or fukt, or ... */
Denys Vlasenkofd3ac962013-07-28 22:24:51 +0200677 FD_CLR(STDIN_FILENO, &ding1); /* disable stdin */
678 /*close(STDIN_FILENO); - not really necessary */
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200679 /* Let peer know we have no more data */
680 /* nc 1.10 doesn't do this: */
681 shutdown(netfd, SHUT_WR);
682 fds_open--;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000683 } else {
684 rzleft = rr;
685 zp = bigbuf_in;
686 }
687 } /* stdin:ding */
688 shovel:
689 /* now that we've dingdonged all our thingdings, send off the results.
690 Geez, why does this look an awful lot like the big loop in "rsh"? ...
691 not sure if the order of this matters, but write net -> stdout first. */
692
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000693 if (rnleft) {
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000694 rr = write(STDOUT_FILENO, np, rnleft);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000695 if (rr > 0) {
Denis Vlasenkoc4f12f52008-05-12 14:35:56 +0000696 if (o_ofile) /* log the stdout */
697 oprint('<', (unsigned char *)np, rr);
Denys Vlasenko05965cb2013-07-29 14:18:32 +0200698 np += rr;
Denys Vlasenkofd3ac962013-07-28 22:24:51 +0200699 rnleft -= rr;
Denys Vlasenko05965cb2013-07-29 14:18:32 +0200700 wrote_out += rr; /* global count */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000701 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000702Debug("wrote %d to stdout, errno %d", rr, errno);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000703 } /* rnleft */
704 if (rzleft) {
705 if (o_interval) /* in "slowly" mode ?? */
706 rr = findline(zp, rzleft);
707 else
708 rr = rzleft;
709 rr = write(netfd, zp, rr); /* one line, or the whole buffer */
710 if (rr > 0) {
Denis Vlasenkoc4f12f52008-05-12 14:35:56 +0000711 if (o_ofile) /* log what got sent */
712 oprint('>', (unsigned char *)zp, rr);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000713 zp += rr;
714 rzleft -= rr;
Denys Vlasenko05965cb2013-07-29 14:18:32 +0200715 wrote_net += rr; /* global count */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000716 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000717Debug("wrote %d to net, errno %d", rr, errno);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000718 } /* rzleft */
719 if (o_interval) { /* cycle between slow lines, or ... */
720 sleep(o_interval);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000721 continue; /* ...with hairy select loop... */
722 }
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200723 if (rzleft || rnleft) { /* shovel that shit till they ain't */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000724 wretry--; /* none left, and get another load */
Denys Vlasenkofd3ac962013-07-28 22:24:51 +0200725 /* net write retries sometimes happen on UDP connections */
726 if (!wretry) { /* is something hung? */
727 holler_error("too many output retries");
728 return 1;
729 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000730 goto shovel;
731 }
Denys Vlasenko05965cb2013-07-29 14:18:32 +0200732 } /* while (fds_open) */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000733
734 /* XXX: maybe want a more graceful shutdown() here, or screw around with
735 linger times?? I suspect that I don't need to since I'm always doing
736 blocking reads and writes and my own manual "last ditch" efforts to read
737 the net again after a timeout. I haven't seen any screwups yet, but it's
738 not like my test network is particularly busy... */
739 close(netfd);
740 return 0;
741} /* readwrite */
742
743/* main: now we pull it all together... */
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000744int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denys Vlasenko2ec91ae2010-01-04 14:15:38 +0100745int nc_main(int argc UNUSED_PARAM, char **argv)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000746{
Denis Vlasenko1d426652008-03-17 09:09:09 +0000747 char *str_p, *str_s;
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000748 IF_NC_EXTRA(char *str_i, *str_o;)
Denys Vlasenko5e896482012-03-19 01:17:36 +0100749 char *themdotted = themdotted; /* for compiler */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000750 char **proggie;
751 int x;
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100752 unsigned cnt_l = 0;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000753 unsigned o_lport = 0;
754
Denis Vlasenko574f2f42008-02-27 18:41:59 +0000755 INIT_G();
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000756
757 /* catch a signal or two for cleanup */
Denis Vlasenko25591c32008-02-16 22:58:56 +0000758 bb_signals(0
759 + (1 << SIGINT)
760 + (1 << SIGQUIT)
761 + (1 << SIGTERM)
762 , catch);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000763 /* and suppress others... */
Denis Vlasenko25591c32008-02-16 22:58:56 +0000764 bb_signals(0
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000765#ifdef SIGURG
Denis Vlasenko25591c32008-02-16 22:58:56 +0000766 + (1 << SIGURG)
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000767#endif
Denis Vlasenko25591c32008-02-16 22:58:56 +0000768 + (1 << SIGPIPE) /* important! */
769 , SIG_IGN);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000770
771 proggie = argv;
772 while (*++proggie) {
773 if (strcmp(*proggie, "-e") == 0) {
774 *proggie = NULL;
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000775 proggie++;
776 goto e_found;
777 }
Denys Vlasenko5e896482012-03-19 01:17:36 +0100778 /* -<other_opts>e PROG [ARGS] ? */
779 /* (aboriginal linux uses this form) */
780 if (proggie[0][0] == '-') {
781 char *optpos = *proggie + 1;
782 /* Skip all valid opts w/o params */
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100783 optpos = optpos + strspn(optpos, "nuv"IF_NC_SERVER("lk")IF_NC_EXTRA("z"));
Denys Vlasenko5e896482012-03-19 01:17:36 +0100784 if (*optpos == 'e' && !optpos[1]) {
785 *optpos = '\0';
786 proggie++;
787 G.proggie0saved = *proggie;
788 *proggie = NULL; /* terminate argv for getopt32 */
789 goto e_found;
790 }
791 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000792 }
793 proggie = NULL;
794 e_found:
Denis Vlasenko4b924f32007-05-30 00:29:55 +0000795
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000796 // -g -G -t -r deleted, unimplemented -a deleted too
Denys Vlasenko237bedd2016-07-06 21:58:02 +0200797 opt_complementary = "?2:vv:ll"; /* max 2 params; -v and -l are counters; -w N */
798 getopt32(argv, "np:s:uvw:+" IF_NC_SERVER("lk")
Denis Vlasenko5e34ff22009-04-21 11:09:40 +0000799 IF_NC_EXTRA("i:o:z"),
Denis Vlasenko1d426652008-03-17 09:09:09 +0000800 &str_p, &str_s, &o_wait
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100801 IF_NC_EXTRA(, &str_i, &str_o), &o_verbose IF_NC_SERVER(, &cnt_l));
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000802 argv += optind;
803#if ENABLE_NC_EXTRA
804 if (option_mask32 & OPT_i) /* line-interval time */
805 o_interval = xatou_range(str_i, 1, 0xffff);
806#endif
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100807#if ENABLE_NC_SERVER
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000808 //if (option_mask32 & OPT_l) /* listen mode */
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100809 if (option_mask32 & OPT_k) /* persistent server mode */
810 cnt_l = 2;
811#endif
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000812 //if (option_mask32 & OPT_n) /* numeric-only, no DNS lookups */
813 //if (option_mask32 & OPT_o) /* hexdump log */
814 if (option_mask32 & OPT_p) { /* local source port */
815 o_lport = bb_lookup_port(str_p, o_udpmode ? "udp" : "tcp", 0);
816 if (!o_lport)
817 bb_error_msg_and_die("bad local port '%s'", str_p);
818 }
819 //if (option_mask32 & OPT_r) /* randomize various things */
820 //if (option_mask32 & OPT_u) /* use UDP */
821 //if (option_mask32 & OPT_v) /* verbose */
Denis Vlasenko1d426652008-03-17 09:09:09 +0000822 //if (option_mask32 & OPT_w) /* wait time */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000823 //if (option_mask32 & OPT_z) /* little or no data xfer */
824
Denis Vlasenko19507f02007-04-06 10:41:05 +0000825 /* We manage our fd's so that they are never 0,1,2 */
826 /*bb_sanitize_stdio(); - not needed */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000827
Denis Vlasenko5c51a7c2007-06-05 20:08:11 +0000828 if (argv[0]) {
829 themaddr = xhost2sockaddr(argv[0],
830 argv[1]
831 ? bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0)
832 : 0);
833 }
834
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000835 /* create & bind network socket */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000836 x = (o_udpmode ? SOCK_DGRAM : SOCK_STREAM);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000837 if (option_mask32 & OPT_s) { /* local address */
Denis Vlasenko19507f02007-04-06 10:41:05 +0000838 /* if o_lport is still 0, then we will use random port */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000839 ouraddr = xhost2sockaddr(str_s, o_lport);
Denis Vlasenko4cf1d082008-03-12 23:13:50 +0000840#ifdef BLOAT
841 /* prevent spurious "UDP listen needs !0 port" */
842 o_lport = get_nport(ouraddr);
843 o_lport = ntohs(o_lport);
844#endif
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000845 x = xsocket(ouraddr->u.sa.sa_family, x, 0);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000846 } else {
Denis Vlasenko5c51a7c2007-06-05 20:08:11 +0000847 /* We try IPv6, then IPv4, unless addr family is
848 * implicitly set by way of remote addr/port spec */
849 x = xsocket_type(&ouraddr,
Denis Vlasenko4e6d5112008-03-12 22:14:34 +0000850 (themaddr ? themaddr->u.sa.sa_family : AF_UNSPEC),
Denis Vlasenko5c51a7c2007-06-05 20:08:11 +0000851 x);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000852 if (o_lport)
Denys Vlasenkoca183112011-04-07 17:52:20 +0200853 set_nport(&ouraddr->u.sa, htons(o_lport));
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000854 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000855 xmove_fd(x, netfd);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000856 setsockopt_reuseaddr(netfd);
857 if (o_udpmode)
858 socket_want_pktinfo(netfd);
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000859 if (!ENABLE_FEATURE_UNIX_LOCAL
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100860 || cnt_l != 0 /* listen */
Denis Vlasenkof6b46852009-04-25 13:16:53 +0000861 || ouraddr->u.sa.sa_family != AF_UNIX
862 ) {
863 xbind(netfd, &ouraddr->u.sa, ouraddr->len);
864 }
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000865#if 0
Denys Vlasenkoc52cbea2015-08-24 19:48:03 +0200866 setsockopt_SOL_SOCKET_int(netfd, SO_RCVBUF, o_rcvbuf);
867 setsockopt_SOL_SOCKET_int(netfd, SO_SNDBUF, o_sndbuf);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000868#endif
869
Denis Vlasenko4cf1d082008-03-12 23:13:50 +0000870#ifdef BLOAT
Denis Vlasenko19507f02007-04-06 10:41:05 +0000871 if (OPT_l && (option_mask32 & (OPT_u|OPT_l)) == (OPT_u|OPT_l)) {
872 /* apparently UDP can listen ON "port 0",
873 but that's not useful */
874 if (!o_lport)
875 bb_error_msg_and_die("UDP listen needs nonzero -p port");
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000876 }
Denis Vlasenko4cf1d082008-03-12 23:13:50 +0000877#endif
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000878
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000879 if (proggie) {
Denys Vlasenkoffeeb7a2013-07-28 22:23:12 +0200880 close(STDIN_FILENO); /* won't need stdin */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000881 option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000882 }
Denis Vlasenko19507f02007-04-06 10:41:05 +0000883#if ENABLE_NC_EXTRA
884 if (o_ofile)
885 xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd);
886#endif
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000887
Denys Vlasenkode6f1482013-02-28 12:20:06 +0100888 if (cnt_l != 0) {
889 dolisten((cnt_l - 1), proggie);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000890 /* dolisten does its own connect reporting */
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000891 x = readwrite(); /* it even works with UDP! */
892 } else {
893 /* Outbound connects. Now we're more picky about args... */
894 if (!themaddr)
Denys Vlasenkob103fb12010-09-07 18:41:56 +0200895 bb_show_usage();
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000896
897 remend = *themaddr;
898 if (o_verbose)
Denis Vlasenko7cff01e2008-02-02 16:23:43 +0000899 themdotted = xmalloc_sockaddr2dotted(&themaddr->u.sa);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000900
901 x = connect_w_timeout(netfd);
902 if (o_zero && x == 0 && o_udpmode) /* if UDP scanning... */
903 x = udptest();
904 if (x == 0) { /* Yow, are we OPEN YET?! */
905 if (o_verbose)
Denis Vlasenko19507f02007-04-06 10:41:05 +0000906 fprintf(stderr, "%s (%s) open\n", argv[0], themdotted);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000907 if (proggie) /* exec is valid for outbound, too */
908 doexec(proggie);
909 if (!o_zero)
910 x = readwrite();
911 } else { /* connect or udptest wasn't successful */
912 x = 1; /* exit status */
913 /* if we're scanning at a "one -v" verbosity level, don't print refusals.
914 Give it another -v if you want to see everything. */
915 if (o_verbose > 1 || (o_verbose && errno != ECONNREFUSED))
Denis Vlasenko19507f02007-04-06 10:41:05 +0000916 bb_perror_msg("%s (%s)", argv[0], themdotted);
Denis Vlasenko29fe7262007-04-05 20:26:28 +0000917 }
918 }
919 if (o_verbose > 1) /* normally we don't care */
920 fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);
921 return x;
922}