1 /* Based on netcat 1.10 RELEASE 960320 written by hobbit@avian.org.
2 * Released into public domain by the author.
4 * Copyright (C) 2007 Denis Vlasenko.
6 * Licensed under GPLv2, see file LICENSE in this tarball for details.
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.
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
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 * =====================
31 * Much of author's comments are still retained in the code.
33 * Functionality removed (rationale):
34 * - miltiple-port ranges, randomized port scanning (use nmap)
35 * - telnet support (use telnet)
37 * - multiple DNS checks
38 * Functionalty which is different from nc 1.10:
39 * - Prog in '-e prog' can have prog's parameters and options.
40 * Because of this -e option must be last.
41 * - nc doesn't redirect stderr to the network socket for the -e prog.
42 * - numeric addresses are printed in (), not [] (IPv6 looks better),
43 * port numbers are inside (): (1.2.3.4:5678)
44 * - network read errors are reported on verbose levels > 1
45 * (nc 1.10 treats them as EOF)
46 * - TCP connects from wrong ip/ports (if peer ip:port is specified
47 * on the command line, but accept() says that it came from different addr)
48 * are closed, but nc doesn't exit - continues to listen/accept.
51 /* done in nc.c: #include "busybox.h" */
54 SLEAZE_PORT = 31337, /* for UDP-scan RTT trick, change if ya want */
55 BIGSIZ = 8192, /* big buffers */
62 /* global cmd flags: */
70 /*int ofd;*/ /* hexdump output fd */
72 #define SENT_N_RECV_M "sent %llu, rcvd %llu\n"
73 unsigned long long wrote_out; /* total stdout bytes */
74 unsigned long long wrote_net; /* total net bytes */
76 #define SENT_N_RECV_M "sent %u, rcvd %u\n"
77 unsigned wrote_out; /* total stdout bytes */
78 unsigned wrote_net; /* total net bytes */
80 /* ouraddr is never NULL and goes thru three states as we progress:
81 1 - local address before bind (IP/port possibly zero)
82 2 - local address after bind (port is nonzero)
83 3 - local address after connect??/recv/accept (IP and port are nonzero) */
84 struct len_and_sockaddr *ouraddr;
85 /* themaddr is NULL if no peer hostname[:port] specified on command line */
86 struct len_and_sockaddr *themaddr;
87 /* remend is set after connect/recv/accept to the actual ip:port of peer */
88 struct len_and_sockaddr remend;
90 jmp_buf jbuf; /* timer crud */
92 /* will malloc up the following globals: */
93 fd_set ding1; /* for select loop */
95 char bigbuf_in[BIGSIZ]; /* data buffers */
96 char bigbuf_net[BIGSIZ];
99 #define G (*ptr_to_globals)
101 #define wrote_out (G.wrote_out )
102 #define wrote_net (G.wrote_net )
103 #define ouraddr (G.ouraddr )
104 #define themaddr (G.themaddr )
105 #define remend (G.remend )
106 #define jbuf (G.jbuf )
107 #define ding1 (G.ding1 )
108 #define ding2 (G.ding2 )
109 #define bigbuf_in (G.bigbuf_in )
110 #define bigbuf_net (G.bigbuf_net)
111 #define o_verbose (G.o_verbose )
112 #define o_wait (G.o_wait )
114 #define o_interval (G.o_interval)
119 /* Must match getopt32 call! */
128 OPT_l = (1 << 7) * ENABLE_NC_SERVER,
129 OPT_i = (1 << (7+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
130 OPT_o = (1 << (8+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
131 OPT_z = (1 << (9+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
134 #define o_nflag (option_mask32 & OPT_n)
135 #define o_udpmode (option_mask32 & OPT_u)
137 #define o_listen (option_mask32 & OPT_l)
142 #define o_ofile (option_mask32 & OPT_o)
143 #define o_zero (option_mask32 & OPT_z)
149 /* Debug: squirt whatever message and sleep a bit so we can see it go by. */
150 /* Beware: writes to stdOUT... */
152 #define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush(stdout); sleep(1); } while (0)
154 #define Debug(...) do { } while (0)
157 #define holler_error(...) do { if (o_verbose) bb_error_msg(__VA_ARGS__); } while (0)
158 #define holler_perror(...) do { if (o_verbose) bb_perror_msg(__VA_ARGS__); } while (0)
160 /* catch: no-brainer interrupt handler */
161 static void catch(int sig)
164 if (o_verbose > 1) /* normally we don't care */
165 fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);
166 fprintf(stderr, "punt!\n");
170 /* timeout and other signal handling cruft */
171 static void tmtravel(int sig)
173 signal(SIGALRM, SIG_IGN);
178 /* arm: set the timer. */
179 static void arm(unsigned secs)
181 signal(SIGALRM, tmtravel);
186 static void unarm(void)
188 signal(SIGALRM, SIG_IGN);
193 find the next newline in a buffer; return inclusive size of that "line",
194 or the entire buffer size, so the caller knows how much to then write().
195 Not distinguishing \n vs \r\n for the nonce; it just works as is... */
196 static unsigned findline(char *buf, unsigned siz)
200 if (!buf) /* various sanity checks... */
205 for (p = buf; x > 0; x--) {
208 x++; /* 'sokay if it points just past the end! */
209 Debug("findline returning %d", x);
214 Debug("findline returning whole thing: %d", siz);
219 fiddle all the file descriptors around, and hand off to another prog. Sort
220 of like a one-off "poor man's inetd". This is the only section of code
221 that would be security-critical, which is why it's ifdefed out by default.
222 Use at your own hairy risk; if you leave shells lying around behind open
223 listening ports you deserve to lose!! */
224 static int doexec(char **proggie) ATTRIBUTE_NORETURN;
225 static int doexec(char **proggie)
229 /* dup2(0, 2); - do we *really* want this? NO!
230 * exec'ed prog can do it yourself, if needed */
231 execvp(proggie[0], proggie);
232 bb_perror_msg_and_die("exec");
235 /* connect_w_timeout:
236 return an fd for one of
237 an open outbound TCP connection, a UDP stub-socket thingie, or
238 an unconnected TCP or UDP socket to listen on.
239 Examines various global o_blah flags to figure out what to do.
240 lad can be NULL, then socket is not bound to any local ip[:port] */
241 static int connect_w_timeout(int fd)
245 /* wrap connect inside a timer, and hit it */
247 if (setjmp(jbuf) == 0) {
248 rr = connect(fd, &themaddr->sa, themaddr->len);
249 } else { /* setjmp: connect failed... */
251 errno = ETIMEDOUT; /* fake it */
259 incoming and returns an open connection *from* someplace. If we were
260 given host/port args, any connections from elsewhere are rejected. This
261 in conjunction with local-address binding should limit things nicely... */
262 static void dolisten(void)
267 xlisten(netfd, 1); /* TCP: gotta listen() before we can get */
269 /* Various things that follow temporarily trash bigbuf_net, which might contain
270 a copy of any recvfrom()ed packet, but we'll read() another copy later. */
272 /* I can't believe I have to do all this to get my own goddamn bound address
273 and port number. It should just get filled in during bind() or something.
274 All this is only useful if we didn't say -p for listening, since if we
275 said -p we *know* what port we're listening on. At any rate we won't bother
276 with it all unless we wanted to see it, although listening quietly on a
277 random unknown port is probably not very useful without "netstat". */
280 rr = getsockname(netfd, &ouraddr->sa, &ouraddr->len);
282 bb_perror_msg_and_die("getsockname after bind");
283 addr = xmalloc_sockaddr2dotted(&ouraddr->sa, ouraddr->len);
284 fprintf(stderr, "listening on %s ...\n", addr);
289 /* UDP is a speeeeecial case -- we have to do I/O *and* get the calling
290 party's particulars all at once, listen() and accept() don't apply.
291 At least in the BSD universe, however, recvfrom/PEEK is enough to tell
292 us something came in, and we can set things up so straight read/write
293 actually does work after all. Yow. YMMV on strange platforms! */
295 /* I'm not completely clear on how this works -- BSD seems to make UDP
296 just magically work in a connect()ed context, but we'll undoubtedly run
297 into systems this deal doesn't work on. For now, we apparently have to
298 issue a connect() on our just-tickled socket so we can write() back.
299 Again, why the fuck doesn't it just get filled in and taken care of?!
300 This hack is anything but optimal. Basically, if you want your listener
301 to also be able to send data back, you need this connect() line, which
302 also has the side effect that now anything from a different source or even a
303 different port on the other end won't show up and will cause ICMP errors.
304 I guess that's what they meant by "connect".
305 Let's try to remember what the "U" is *really* for, eh? */
307 /* If peer address is specified, connect to it */
308 remend.len = LSA_SIZEOF_SA;
311 xconnect(netfd, &themaddr->sa, themaddr->len);
313 /* peek first packet and remember peer addr */
314 arm(o_wait); /* might as well timeout this, too */
315 if (setjmp(jbuf) == 0) { /* do timeout for initial connect */
316 /* (*ouraddr) is prefilled with "default" address */
317 /* and here we block... */
318 rr = recv_from_to(netfd, NULL, 0, MSG_PEEK, /*was bigbuf_net, BIGSIZ*/
319 &remend.sa, &ouraddr->sa, ouraddr->len);
321 bb_perror_msg_and_die("recvfrom");
323 bb_error_msg_and_die("timeout");
325 /* Now we learned *to which IP* peer has connected, and we want to anchor
326 our socket on it, so that our outbound packets will have correct local IP.
327 Unfortunately, bind() on already bound socket will fail now (EINVAL):
328 xbind(netfd, &ouraddr->sa, ouraddr->len);
329 Need to read the packet, save data, close this socket and
330 create new one, and bind() it. TODO */
332 xconnect(netfd, &remend.sa, ouraddr->len);
335 arm(o_wait); /* wrap this in a timer, too; 0 = forever */
336 if (setjmp(jbuf) == 0) {
338 remend.len = LSA_SIZEOF_SA;
339 rr = accept(netfd, &remend.sa, &remend.len);
341 bb_perror_msg_and_die("accept");
342 if (themaddr && memcmp(&remend.sa, &themaddr->sa, remend.len) != 0) {
343 /* nc 1.10 bails out instead, and its error message
344 * is not suppressed by o_verbose */
346 char *remaddr = xmalloc_sockaddr2dotted(&remend.sa, remend.len);
347 bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
355 bb_error_msg_and_die("timeout");
357 xmove_fd(rr, netfd); /* dump the old socket, here's our new one */
358 /* find out what address the connection was *to* on our end, in case we're
359 doing a listen-on-any on a multihomed machine. This allows one to
360 offer different services via different alias addresses, such as the
361 "virtual web site" hack. */
362 rr = getsockname(netfd, &ouraddr->sa, &ouraddr->len);
364 bb_perror_msg_and_die("getsockname after accept");
368 char *lcladdr, *remaddr, *remhostname;
370 #if ENABLE_NC_EXTRA && defined(IP_OPTIONS)
371 /* If we can, look for any IP options. Useful for testing the receiving end of
372 such things, and is a good exercise in dealing with it. We do this before
373 the connect message, to ensure that the connect msg is uniformly the LAST
374 thing to emerge after all the intervening crud. Doesn't work for UDP on
375 any machines I've tested, but feel free to surprise me. */
377 int x = sizeof(optbuf);
379 rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x);
381 bb_perror_msg("getsockopt failed");
382 else if (x) { /* we've got options, lessee em... */
383 bin2hex(bigbuf_net, optbuf, x);
384 bigbuf_net[2*x] = '\0';
385 fprintf(stderr, "IP options: %s\n", bigbuf_net);
389 /* now check out who it is. We don't care about mismatched DNS names here,
390 but any ADDR and PORT we specified had better fucking well match the caller.
391 Converting from addr to inet_ntoa and back again is a bit of a kludge, but
392 gethostpoop wants a string and there's much gnarlier code out there already,
394 The *real* question is why BFD sockets wasn't designed to allow listens for
395 connections *from* specific hosts/ports, instead of requiring the caller to
396 accept the connection and then reject undesireable ones by closing.
397 In other words, we need a TCP MSG_PEEK. */
398 /* bbox: removed most of it */
399 lcladdr = xmalloc_sockaddr2dotted(&ouraddr->sa, ouraddr->len);
400 remaddr = xmalloc_sockaddr2dotted(&remend.sa, remend.len);
401 remhostname = o_nflag ? remaddr : xmalloc_sockaddr2host(&remend.sa, remend.len);
402 fprintf(stderr, "connect to %s from %s (%s)\n",
403 lcladdr, remhostname, remaddr);
412 fire a couple of packets at a UDP target port, just to see if it's really
413 there. On BSD kernels, ICMP host/port-unreachable errors get delivered to
414 our socket as ECONNREFUSED write errors. On SV kernels, we lose; we'll have
415 to collect and analyze raw ICMP ourselves a la satan's probe_udp_ports
416 backend. Guess where one could swipe the appropriate code from...
418 Use the time delay between writes if given, otherwise use the "tcp ping"
419 trick for getting the RTT. [I got that idea from pluvius, and warped it.]
420 Return either the original fd, or clean up and return -1. */
422 static int udptest(void)
426 rr = write(netfd, bigbuf_in, 1);
428 bb_perror_msg("udptest first write");
431 sleep(o_wait); // can be interrupted! while (t) nanosleep(&t)?
433 /* use the tcp-ping trick: try connecting to a normally refused port, which
434 causes us to block for the time that SYN gets there and RST gets back.
435 Not completely reliable, but it *does* mostly work. */
436 /* Set a temporary connect timeout, so packet filtration doesnt cause
437 us to hang forever, and hit it */
438 o_wait = 5; /* enough that we'll notice?? */
439 rr = xsocket(ouraddr->sa.sa_family, SOCK_STREAM, 0);
440 set_nport(themaddr, htons(SLEAZE_PORT));
441 connect_w_timeout(rr);
442 /* don't need to restore themaddr's port, it's not used anymore */
444 o_wait = 0; /* restore */
447 rr = write(netfd, bigbuf_in, 1);
448 return (rr != 1); /* if rr == 1, return 0 (success) */
455 Hexdump bytes shoveled either way to a running logfile, in the format:
456 D offset - - - - --- 16 bytes --- - - - - # .... ascii .....
457 where "which" sets the direction indicator, D:
458 0 -- sent to network, or ">"
459 1 -- rcvd and printed to stdout, or "<"
460 and "buf" and "n" are data-block and length. If the current block generates
461 a partial line, so be it; we *want* that lockstep indication of who sent
462 what when. Adapted from dgaudet's original example -- but must be ripping
463 *fast*, since we don't want to be too disk-bound... */
465 static void oprint(int direction, unsigned char *p, int bc)
467 int obc; /* current "global" offset */
468 int soc; /* stage write count */
469 unsigned char *op; /* out hexdump ptr */
470 unsigned char *a; /* out asc-dump ptr */
472 unsigned char stage[100];
478 obc = wrote_net; /* use the globals! */
479 if (direction == '<')
483 stage[59] = '#'; /* preload separator */
486 while (bc) { /* for chunk-o-data ... */
488 soc = 78; /* len of whole formatted line */
490 soc = soc - 16 + bc; /* fiddle for however much is left */
491 x = (bc * 3) + 11; /* 2 digits + space per, after D & offset */
495 *op++ = ' '; /* preload filler spaces */
500 x = bc; /* re-fix current linecount */
503 bc -= x; /* fix wrt current line size */
504 sprintf(&stage[2], "%8.8x ", obc); /* xxx: still slow? */
505 obc += x; /* fix current offset */
506 op = &stage[11]; /* where hex starts */
507 a = &stage[61]; /* where ascii starts */
509 while (x) { /* for line of dump, however long ... */
510 *op++ = 0x20 | bb_hexdigits_upcase[*p >> 4];
511 *op++ = 0x20 | bb_hexdigits_upcase[*p & 0x0f];
513 if ((*p > 31) && (*p < 127))
514 *a = *p; /* printing */
516 *a = '.'; /* nonprinting, loose def */
521 *a = '\n'; /* finish the line */
522 xwrite(ofd, stage, soc);
526 void oprint(int direction, unsigned char *p, int bc);
530 handle stdin/stdout/network I/O. Bwahaha!! -- the select loop from hell.
531 In this instance, return what might become our exit status. */
532 static int readwrite(void)
535 char *zp = zp; /* gcc */ /* stdin buf ptr */
536 char *np = np; /* net-in buf ptr */
539 unsigned netretry; /* net-read retry counter */
540 unsigned wretry; /* net-write sanity counter */
541 unsigned wfirst; /* one-shot flag to skip first net read */
543 /* if you don't have all this FD_* macro hair in sys/types.h, you'll have to
544 either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */
545 FD_SET(netfd, &ding1); /* global: the net is open */
550 sleep(o_interval); /* pause *before* sending stuff, too */
552 errno = 0; /* clear from sleep, close, whatever */
553 /* and now the big ol' select shoveling loop ... */
554 while (FD_ISSET(netfd, &ding1)) { /* i.e. till the *net* closes! */
555 wretry = 8200; /* more than we'll ever hafta write */
556 if (wfirst) { /* any saved stdin buffer? */
557 wfirst = 0; /* clear flag for the duration */
558 goto shovel; /* and go handle it first */
560 ding2 = ding1; /* FD_COPY ain't portable... */
561 /* some systems, notably linux, crap into their select timers on return, so
562 we create a expendable copy and give *that* to select. */
564 struct timeval tmp_timer;
565 tmp_timer.tv_sec = o_wait;
566 tmp_timer.tv_usec = 0;
567 /* highest possible fd is netfd (3) */
568 rr = select(netfd+1, &ding2, NULL, NULL, &tmp_timer);
570 rr = select(netfd+1, &ding2, NULL, NULL, NULL);
571 if (rr < 0 && errno != EINTR) { /* might have gotten ^Zed, etc */
572 holler_perror("select");
576 /* if we have a timeout AND stdin is closed AND we haven't heard anything
577 from the net during that time, assume it's dead and close it too. */
579 if (!FD_ISSET(0, &ding1))
580 netretry--; /* we actually try a coupla times. */
582 if (o_verbose > 1) /* normally we don't care */
583 fprintf(stderr, "net timeout\n");
585 return 0; /* not an error! */
587 } /* select timeout */
588 /* xxx: should we check the exception fds too? The read fds seem to give
589 us the right info, and none of the examples I found bothered. */
591 /* Ding!! Something arrived, go check all the incoming hoppers, net first */
592 if (FD_ISSET(netfd, &ding2)) { /* net: ding! */
593 rr = read(netfd, bigbuf_net, BIGSIZ);
595 if (rr < 0 && o_verbose > 1) {
596 /* nc 1.10 doesn't do this */
597 bb_perror_msg("net read");
599 FD_CLR(netfd, &ding1); /* net closed, we'll finish up... */
600 rzleft = 0; /* can't write anymore: broken pipe */
605 Debug("got %d from the net, errno %d", rr, errno);
608 /* if we're in "slowly" mode there's probably still stuff in the stdin
609 buffer, so don't read unless we really need MORE INPUT! MORE INPUT! */
613 /* okay, suck more stdin */
614 if (FD_ISSET(0, &ding2)) { /* stdin: ding! */
615 rr = read(0, bigbuf_in, BIGSIZ);
616 /* Considered making reads here smaller for UDP mode, but 8192-byte
617 mobygrams are kinda fun and exercise the reassembler. */
618 if (rr <= 0) { /* at end, or fukt, or ... */
619 FD_CLR(0, &ding1); /* disable and close stdin */
627 /* now that we've dingdonged all our thingdings, send off the results.
628 Geez, why does this look an awful lot like the big loop in "rsh"? ...
629 not sure if the order of this matters, but write net -> stdout first. */
631 /* sanity check. Works because they're both unsigned... */
632 if ((rzleft > 8200) || (rnleft > 8200)) {
633 holler_error("bogus buffers: %u, %u", rzleft, rnleft);
636 /* net write retries sometimes happen on UDP connections */
637 if (!wretry) { /* is something hung? */
638 holler_error("too many output retries");
642 rr = write(1, np, rnleft);
645 oprint('<', np, rr); /* log the stdout */
646 np += rr; /* fix up ptrs and whatnot */
647 rnleft -= rr; /* will get sanity-checked above */
648 wrote_out += rr; /* global count */
650 Debug("wrote %d to stdout, errno %d", rr, errno);
653 if (o_interval) /* in "slowly" mode ?? */
654 rr = findline(zp, rzleft);
657 rr = write(netfd, zp, rr); /* one line, or the whole buffer */
660 oprint('>', zp, rr); /* log what got sent */
663 wrote_net += rr; /* global count */
665 Debug("wrote %d to net, errno %d", rr, errno);
667 if (o_interval) { /* cycle between slow lines, or ... */
669 errno = 0; /* clear from sleep */
670 continue; /* ...with hairy select loop... */
672 if ((rzleft) || (rnleft)) { /* shovel that shit till they ain't */
673 wretry--; /* none left, and get another load */
676 } /* while ding1:netfd is open */
678 /* XXX: maybe want a more graceful shutdown() here, or screw around with
679 linger times?? I suspect that I don't need to since I'm always doing
680 blocking reads and writes and my own manual "last ditch" efforts to read
681 the net again after a timeout. I haven't seen any screwups yet, but it's
682 not like my test network is particularly busy... */
687 /* main: now we pull it all together... */
688 int nc_main(int argc, char **argv);
689 int nc_main(int argc, char **argv)
691 char *str_p, *str_s, *str_w;
692 USE_NC_EXTRA(char *str_i, *str_o;)
693 char *themdotted = themdotted; /* gcc */
696 unsigned o_lport = 0;
698 /* I was in this barbershop quartet in Skokie IL ... */
699 /* round up the usual suspects, i.e. malloc up all the stuff we need */
700 PTR_TO_GLOBALS = xzalloc(sizeof(G));
702 /* catch a signal or two for cleanup */
703 signal(SIGINT, catch);
704 signal(SIGQUIT, catch);
705 signal(SIGTERM, catch);
706 /* and suppress others... */
708 signal(SIGURG, SIG_IGN);
710 signal(SIGPIPE, SIG_IGN); /* important! */
714 if (strcmp(*proggie, "-e") == 0) {
716 argc = proggie - argv;
724 // -g -G -t -r deleted, unimplemented -a deleted too
725 opt_complementary = "?2:vv"; /* max 2 params, -v is a counter */
726 getopt32(argc, argv, "hnp:s:uvw:" USE_NC_SERVER("l")
727 USE_NC_EXTRA("i:o:z"),
728 &str_p, &str_s, &str_w
729 USE_NC_EXTRA(, &str_i, &str_o, &o_verbose));
732 if (option_mask32 & OPT_i) /* line-interval time */
733 o_interval = xatou_range(str_i, 1, 0xffff);
735 //if (option_mask32 & OPT_l) /* listen mode */
736 //if (option_mask32 & OPT_n) /* numeric-only, no DNS lookups */
737 //if (option_mask32 & OPT_o) /* hexdump log */
738 if (option_mask32 & OPT_p) { /* local source port */
739 o_lport = bb_lookup_port(str_p, o_udpmode ? "udp" : "tcp", 0);
741 bb_error_msg_and_die("bad local port '%s'", str_p);
743 //if (option_mask32 & OPT_r) /* randomize various things */
744 //if (option_mask32 & OPT_u) /* use UDP */
745 //if (option_mask32 & OPT_v) /* verbose */
746 if (option_mask32 & OPT_w) { /* wait time */
747 o_wait = xatoi_u(str_w);
749 //if (option_mask32 & OPT_z) /* little or no data xfer */
751 /* We manage our fd's so that they are never 0,1,2 */
752 /*bb_sanitize_stdio(); - not needed */
754 /* create & bind network socket */
755 x = (o_udpmode ? SOCK_DGRAM : SOCK_STREAM);
756 if (option_mask32 & OPT_s) { /* local address */
757 /* if o_lport is still 0, then we will use random port */
758 ouraddr = xhost2sockaddr(str_s, o_lport);
759 x = xsocket(ouraddr->sa.sa_family, x, 0);
761 x = xsocket_type(&ouraddr, x);
763 set_nport(ouraddr, htons(o_lport));
766 setsockopt_reuseaddr(netfd);
768 socket_want_pktinfo(netfd);
769 xbind(netfd, &ouraddr->sa, ouraddr->len);
771 setsockopt(netfd, SOL_SOCKET, SO_RCVBUF, &o_rcvbuf, sizeof o_rcvbuf);
772 setsockopt(netfd, SOL_SOCKET, SO_SNDBUF, &o_sndbuf, sizeof o_sndbuf);
775 if (OPT_l && (option_mask32 & (OPT_u|OPT_l)) == (OPT_u|OPT_l)) {
776 /* apparently UDP can listen ON "port 0",
777 but that's not useful */
779 bb_error_msg_and_die("UDP listen needs nonzero -p port");
782 FD_SET(0, &ding1); /* stdin *is* initially open */
784 close(0); /* won't need stdin */
785 option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
789 xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd);
793 themaddr = xhost2sockaddr(argv[0],
795 ? bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0)
797 ///what if sa_family won't match??
802 /* dolisten does its own connect reporting */
803 if (proggie) /* -e given? */
805 x = readwrite(); /* it even works with UDP! */
807 /* Outbound connects. Now we're more picky about args... */
809 bb_error_msg_and_die("no destination");
813 themdotted = xmalloc_sockaddr2dotted(&themaddr->sa, themaddr->len);
815 x = connect_w_timeout(netfd);
816 if (o_zero && x == 0 && o_udpmode) /* if UDP scanning... */
818 if (x == 0) { /* Yow, are we OPEN YET?! */
820 fprintf(stderr, "%s (%s) open\n", argv[0], themdotted);
821 if (proggie) /* exec is valid for outbound, too */
825 } else { /* connect or udptest wasn't successful */
826 x = 1; /* exit status */
827 /* if we're scanning at a "one -v" verbosity level, don't print refusals.
828 Give it another -v if you want to see everything. */
829 if (o_verbose > 1 || (o_verbose && errno != ECONNREFUSED))
830 bb_perror_msg("%s (%s)", argv[0], themdotted);
833 if (o_verbose > 1) /* normally we don't care */
834 fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);