busybox/networking/nc_bloaty.c

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/* Based on netcat 1.10 RELEASE 960320 written by hobbit@avian.org.
* Released into public domain by the author.
*
* Copyright (C) 2007 Denys Vlasenko.
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*
* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
/* Author's comments from nc 1.10:
* =====================
* Netcat is entirely my own creation, although plenty of other code was used as
* examples. It is freely given away to the Internet community in the hope that
* it will be useful, with no restrictions except giving credit where it is due.
* No GPLs, Berkeley copyrights or any of that nonsense. The author assumes NO
* responsibility for how anyone uses it. If netcat makes you rich somehow and
* you're feeling generous, mail me a check. If you are affiliated in any way
* with Microsoft Network, get a life. Always ski in control. Comments,
* questions, and patches to hobbit@avian.org.
* ...
* Netcat and the associated package is a product of Avian Research, and is freely
* available in full source form with no restrictions save an obligation to give
* credit where due.
* ...
* A damn useful little "backend" utility begun 950915 or thereabouts,
* as *Hobbit*'s first real stab at some sockets programming. Something that
* should have and indeed may have existed ten years ago, but never became a
* standard Unix utility. IMHO, "nc" could take its place right next to cat,
* cp, rm, mv, dd, ls, and all those other cryptic and Unix-like things.
* =====================
*
* Much of author's comments are still retained in the code.
*
* Functionality removed (rationale):
* - miltiple-port ranges, randomized port scanning (use nmap)
* - telnet support (use telnet)
* - source routing
* - multiple DNS checks
* Functionalty which is different from nc 1.10:
* - PROG in '-e PROG' can have ARGS (and options).
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* Because of this -e option must be last.
//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 we don't exit - we continue to listen/accept.
* Since bbox 1.22:
* - nc exits when _both_ stdin and network are closed.
* This makes these two commands:
* echo "Yes" | nc 127.0.0.1 1234
* echo "no" | nc -lp 1234
* exchange their data _and exit_ instead of being stuck.
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*/
/* done in nc.c: #include "libbb.h" */
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//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 */
netfd = 3,
ofd = 4,
};
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struct globals {
/* global cmd flags: */
unsigned o_verbose;
unsigned o_wait;
#if ENABLE_NC_EXTRA
unsigned o_interval;
#endif
/*int netfd;*/
/*int ofd;*/ /* hexdump output fd */
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#if ENABLE_LFS
#define SENT_N_RECV_M "sent %llu, rcvd %llu\n"
unsigned long long wrote_out; /* total stdout bytes */
unsigned long long wrote_net; /* total net bytes */
#else
#define SENT_N_RECV_M "sent %u, rcvd %u\n"
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unsigned wrote_out; /* total stdout bytes */
unsigned wrote_net; /* total net bytes */
#endif
char *proggie0saved;
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/* ouraddr is never NULL and goes through three states as we progress:
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1 - local address before bind (IP/port possibly zero)
2 - local address after bind (port is nonzero)
3 - local address after connect??/recv/accept (IP and port are nonzero) */
struct len_and_sockaddr *ouraddr;
/* themaddr is NULL if no peer hostname[:port] specified on command line */
struct len_and_sockaddr *themaddr;
/* remend is set after connect/recv/accept to the actual ip:port of peer */
struct len_and_sockaddr remend;
jmp_buf jbuf; /* timer crud */
char bigbuf_in[BIGSIZ]; /* data buffers */
char bigbuf_net[BIGSIZ];
};
#define G (*ptr_to_globals)
#define wrote_out (G.wrote_out )
#define wrote_net (G.wrote_net )
#define ouraddr (G.ouraddr )
#define themaddr (G.themaddr )
#define remend (G.remend )
#define jbuf (G.jbuf )
#define bigbuf_in (G.bigbuf_in )
#define bigbuf_net (G.bigbuf_net)
#define o_verbose (G.o_verbose )
#define o_wait (G.o_wait )
#if ENABLE_NC_EXTRA
#define o_interval (G.o_interval)
#else
#define o_interval 0
#endif
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)
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/* Must match getopt32 call! */
enum {
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 << (6+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
OPT_o = (1 << (7+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
OPT_z = (1 << (8+2*ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
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};
#define o_nflag (option_mask32 & OPT_n)
#define o_udpmode (option_mask32 & OPT_u)
#if ENABLE_NC_EXTRA
#define o_ofile (option_mask32 & OPT_o)
#define o_zero (option_mask32 & OPT_z)
#else
#define o_ofile 0
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#define o_zero 0
#endif
/* Debug: squirt whatever message and sleep a bit so we can see it go by. */
/* Beware: writes to stdOUT... */
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#if 0
#define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush_all(); sleep(1); } while (0)
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#else
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#define Debug(...) do { } while (0)
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#endif
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#define holler_error(...) do { if (o_verbose) bb_error_msg(__VA_ARGS__); } while (0)
#define holler_perror(...) do { if (o_verbose) bb_perror_msg(__VA_ARGS__); } while (0)
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/* catch: no-brainer interrupt handler */
static void catch(int sig)
{
if (o_verbose > 1) /* normally we don't care */
fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);
fprintf(stderr, "punt!\n");
kill_myself_with_sig(sig);
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}
/* unarm */
static void unarm(void)
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{
signal(SIGALRM, SIG_IGN);
alarm(0);
}
/* timeout and other signal handling cruft */
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static void tmtravel(int sig UNUSED_PARAM)
{
unarm();
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longjmp(jbuf, 1);
}
/* arm: set the timer. */
static void arm(unsigned secs)
{
signal(SIGALRM, tmtravel);
alarm(secs);
}
/* findline:
find the next newline in a buffer; return inclusive size of that "line",
or the entire buffer size, so the caller knows how much to then write().
Not distinguishing \n vs \r\n for the nonce; it just works as is... */
static unsigned findline(char *buf, unsigned siz)
{
char * p;
int x;
if (!buf) /* various sanity checks... */
return 0;
if (siz > BIGSIZ)
return 0;
x = siz;
for (p = buf; x > 0; x--) {
if (*p == '\n') {
x = (int) (p - buf);
x++; /* 'sokay if it points just past the end! */
Debug("findline returning %d", x);
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return x;
}
p++;
} /* for */
Debug("findline returning whole thing: %d", siz);
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return siz;
} /* findline */
/* doexec:
fiddle all the file descriptors around, and hand off to another prog. Sort
of like a one-off "poor man's inetd". This is the only section of code
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!! */
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static int doexec(char **proggie) NORETURN;
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static int doexec(char **proggie)
{
if (G.proggie0saved)
proggie[0] = G.proggie0saved;
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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 */
BB_EXECVP_or_die(proggie);
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}
/* connect_w_timeout:
return an fd for one of
an open outbound TCP connection, a UDP stub-socket thingie, or
an unconnected TCP or UDP socket to listen on.
Examines various global o_blah flags to figure out what to do.
lad can be NULL, then socket is not bound to any local ip[:port] */
static int connect_w_timeout(int fd)
{
int rr;
/* wrap connect inside a timer, and hit it */
arm(o_wait);
if (setjmp(jbuf) == 0) {
rr = connect(fd, &themaddr->u.sa, themaddr->len);
unarm();
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} else { /* setjmp: connect failed... */
rr = -1;
errno = ETIMEDOUT; /* fake it */
}
return rr;
}
/* dolisten:
listens for
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(int is_persistent, char **proggie)
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{
int rr;
if (!o_udpmode)
xlisten(netfd, 1); /* TCP: gotta listen() before we can get */
/* Various things that follow temporarily trash bigbuf_net, which might contain
a copy of any recvfrom()ed packet, but we'll read() another copy later. */
/* I can't believe I have to do all this to get my own goddamn bound address
and port number. It should just get filled in during bind() or something.
All this is only useful if we didn't say -p for listening, since if we
said -p we *know* what port we're listening on. At any rate we won't bother
with it all unless we wanted to see it, although listening quietly on a
random unknown port is probably not very useful without "netstat". */
if (o_verbose) {
char *addr;
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);
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free(addr);
}
if (o_udpmode) {
/* UDP is a speeeeecial case -- we have to do I/O *and* get the calling
party's particulars all at once, listen() and accept() don't apply.
At least in the BSD universe, however, recvfrom/PEEK is enough to tell
us something came in, and we can set things up so straight read/write
actually does work after all. Yow. YMMV on strange platforms! */
/* I'm not completely clear on how this works -- BSD seems to make UDP
just magically work in a connect()ed context, but we'll undoubtedly run
into systems this deal doesn't work on. For now, we apparently have to
issue a connect() on our just-tickled socket so we can write() back.
Again, why the fuck doesn't it just get filled in and taken care of?!
This hack is anything but optimal. Basically, if you want your listener
to also be able to send data back, you need this connect() line, which
also has the side effect that now anything from a different source or even a
different port on the other end won't show up and will cause ICMP errors.
I guess that's what they meant by "connect".
Let's try to remember what the "U" is *really* for, eh? */
/* If peer address is specified, connect to it */
remend.len = LSA_SIZEOF_SA;
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if (themaddr) {
remend = *themaddr;
xconnect(netfd, &themaddr->u.sa, themaddr->len);
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}
/* peek first packet and remember peer addr */
arm(o_wait); /* might as well timeout this, too */
if (setjmp(jbuf) == 0) { /* do timeout for initial connect */
/* (*ouraddr) is prefilled with "default" address */
/* and here we block... */
rr = recv_from_to(netfd, NULL, 0, MSG_PEEK, /*was bigbuf_net, BIGSIZ*/
&remend.u.sa, &ouraddr->u.sa, ouraddr->len);
if (rr < 0)
bb_perror_msg_and_die("recvfrom");
unarm();
} else
bb_error_msg_and_die("timeout");
/* Now we learned *to which IP* peer has connected, and we want to anchor
our socket on it, so that our outbound packets will have correct local IP.
Unfortunately, bind() on already bound socket will fail now (EINVAL):
xbind(netfd, &ouraddr->u.sa, ouraddr->len);
Need to read the packet, save data, close this socket and
create new one, and bind() it. TODO */
if (!themaddr)
xconnect(netfd, &remend.u.sa, ouraddr->len);
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} else {
/* TCP */
another:
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arm(o_wait); /* wrap this in a timer, too; 0 = forever */
if (setjmp(jbuf) == 0) {
again:
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remend.len = LSA_SIZEOF_SA;
rr = accept(netfd, &remend.u.sa, &remend.len);
if (rr < 0)
bb_perror_msg_and_die("accept");
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;
}
}
unarm();
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} 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. */
getsockname(netfd, &ouraddr->u.sa, &ouraddr->len);
//if (rr < 0)
// bb_perror_msg_and_die("getsockname after accept");
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}
if (o_verbose) {
char *lcladdr, *remaddr, *remhostname;
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#if ENABLE_NC_EXTRA && defined(IP_OPTIONS)
/* If we can, look for any IP options. Useful for testing the receiving end of
such things, and is a good exercise in dealing with it. We do this before
the connect message, to ensure that the connect msg is uniformly the LAST
thing to emerge after all the intervening crud. Doesn't work for UDP on
any machines I've tested, but feel free to surprise me. */
char optbuf[40];
socklen_t x = sizeof(optbuf);
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rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x);
if (rr >= 0 && x) { /* we've got options, lessee em... */
*bin2hex(bigbuf_net, optbuf, x) = '\0';
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fprintf(stderr, "IP options: %s\n", bigbuf_net);
}
#endif
/* now check out who it is. We don't care about mismatched DNS names here,
but any ADDR and PORT we specified had better fucking well match the caller.
Converting from addr to inet_ntoa and back again is a bit of a kludge, but
gethostpoop wants a string and there's much gnarlier code out there already,
so I don't feel bad.
The *real* question is why BFD sockets wasn't designed to allow listens for
connections *from* specific hosts/ports, instead of requiring the caller to
accept the connection and then reject undesirable ones by closing.
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In other words, we need a TCP MSG_PEEK. */
/* bbox: removed most of it */
lcladdr = xmalloc_sockaddr2dotted(&ouraddr->u.sa);
remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
remhostname = o_nflag ? remaddr : xmalloc_sockaddr2host(&remend.u.sa);
fprintf(stderr, "connect to %s from %s (%s)\n",
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lcladdr, remhostname, remaddr);
free(lcladdr);
free(remaddr);
if (!o_nflag)
free(remhostname);
}
if (proggie)
doexec(proggie);
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}
/* udptest:
fire a couple of packets at a UDP target port, just to see if it's really
there. On BSD kernels, ICMP host/port-unreachable errors get delivered to
our socket as ECONNREFUSED write errors. On SV kernels, we lose; we'll have
to collect and analyze raw ICMP ourselves a la satan's probe_udp_ports
backend. Guess where one could swipe the appropriate code from...
Use the time delay between writes if given, otherwise use the "tcp ping"
trick for getting the RTT. [I got that idea from pluvius, and warped it.]
Return either the original fd, or clean up and return -1. */
#if ENABLE_NC_EXTRA
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static int udptest(void)
{
int rr;
rr = write(netfd, bigbuf_in, 1);
if (rr != 1)
bb_perror_msg("udptest first write");
if (o_wait)
sleep(o_wait); // can be interrupted! while (t) nanosleep(&t)?
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else {
/* use the tcp-ping trick: try connecting to a normally refused port, which
causes us to block for the time that SYN gets there and RST gets back.
Not completely reliable, but it *does* mostly work. */
/* Set a temporary connect timeout, so packet filtration doesn't cause
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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->u.sa, htons(SLEAZE_PORT));
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connect_w_timeout(rr);
/* don't need to restore themaddr's port, it's not used anymore */
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close(rr);
o_wait = 0; /* restore */
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}
rr = write(netfd, bigbuf_in, 1);
return (rr != 1); /* if rr == 1, return 0 (success) */
}
#else
int udptest(void);
#endif
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/* oprint:
Hexdump bytes shoveled either way to a running logfile, in the format:
D offset - - - - --- 16 bytes --- - - - - # .... ascii .....
where "which" sets the direction indicator, D:
0 -- sent to network, or ">"
1 -- rcvd and printed to stdout, or "<"
and "buf" and "n" are data-block and length. If the current block generates
a partial line, so be it; we *want* that lockstep indication of who sent
what when. Adapted from dgaudet's original example -- but must be ripping
*fast*, since we don't want to be too disk-bound... */
#if ENABLE_NC_EXTRA
static void oprint(int direction, unsigned char *p, unsigned bc)
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{
unsigned obc; /* current "global" offset */
unsigned x;
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unsigned char *op; /* out hexdump ptr */
unsigned char *ap; /* out asc-dump ptr */
unsigned char stage[100];
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if (bc == 0)
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return;
obc = wrote_net; /* use the globals! */
if (direction == '<')
obc = wrote_out;
stage[0] = direction;
stage[59] = '#'; /* preload separator */
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stage[60] = ' ';
do { /* for chunk-o-data ... */
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x = 16;
if (bc < 16) {
/* memset(&stage[bc*3 + 11], ' ', 16*3 - bc*3); */
memset(&stage[11], ' ', 16*3);
x = bc;
}
sprintf((char *)&stage[1], " %8.8x ", obc); /* xxx: still slow? */
bc -= x; /* fix current count */
obc += x; /* fix current offset */
op = &stage[11]; /* where hex starts */
ap = &stage[61]; /* where ascii starts */
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do { /* for line of dump, however long ... */
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*op++ = 0x20 | bb_hexdigits_upcase[*p >> 4];
*op++ = 0x20 | bb_hexdigits_upcase[*p & 0x0f];
*op++ = ' ';
if ((*p > 31) && (*p < 127))
*ap = *p; /* printing */
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else
*ap = '.'; /* nonprinting, loose def */
ap++;
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p++;
} while (--x);
*ap++ = '\n'; /* finish the line */
xwrite(ofd, stage, ap - stage);
} while (bc);
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}
#else
void oprint(int direction, unsigned char *p, unsigned bc);
#endif
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/* readwrite:
handle stdin/stdout/network I/O. Bwahaha!! -- the i/o loop from hell.
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In this instance, return what might become our exit status. */
static int readwrite(void)
{
char *zp = zp; /* gcc */ /* stdin buf ptr */
char *np = np; /* net-in buf ptr */
unsigned rzleft;
unsigned rnleft;
unsigned netretry; /* net-read retry counter */
unsigned fds_open;
2007-04-06 01:56:28 +05:30
struct pollfd pfds[2];
pfds[0].fd = STDIN_FILENO;
pfds[0].events = POLLIN;
pfds[1].fd = netfd;
pfds[1].events = POLLIN;
fds_open = 2;
2007-04-06 01:56:28 +05:30
netretry = 2;
rzleft = rnleft = 0;
if (o_interval)
sleep(o_interval); /* pause *before* sending stuff, too */
/* and now the big ol' shoveling loop ... */
/* nc 1.10 has "while (FD_ISSET(netfd)" here */
while (fds_open) {
int rr;
int poll_tmout_ms;
unsigned wretry = 8200; /* net-write sanity counter */
poll_tmout_ms = -1;
2007-04-06 01:56:28 +05:30
if (o_wait) {
poll_tmout_ms = INT_MAX;
if (o_wait < INT_MAX / 1000)
poll_tmout_ms = o_wait * 1000;
}
rr = poll(pfds, 2, poll_tmout_ms);
2007-04-06 01:56:28 +05:30
if (rr < 0 && errno != EINTR) { /* might have gotten ^Zed, etc */
holler_perror("poll");
2007-04-06 01:56:28 +05:30
close(netfd);
return 1;
}
/* 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 (!pfds[0].revents) {
2007-04-06 01:56:28 +05:30
netretry--; /* we actually try a coupla times. */
if (!netretry) {
if (o_verbose > 1) /* normally we don't care */
fprintf(stderr, "net timeout\n");
/*close(netfd); - redundant, exit will do it */
return 0; /* not an error! */
}
2007-04-06 01:56:28 +05:30
}
} /* timeout */
2007-04-06 01:56:28 +05:30
/* Ding!! Something arrived, go check all the incoming hoppers, net first */
if (pfds[1].revents) { /* net: ding! */
2007-04-06 01:56:28 +05:30
rr = read(netfd, bigbuf_net, BIGSIZ);
if (rr <= 0) {
if (rr < 0 && o_verbose > 1) {
/* nc 1.10 doesn't do this */
bb_perror_msg("net read");
}
pfds[1].fd = -1; /* don't poll for netfd anymore */
fds_open--;
2007-04-06 01:56:28 +05:30
rzleft = 0; /* can't write anymore: broken pipe */
} else {
rnleft = rr;
np = bigbuf_net;
}
Debug("got %d from the net, errno %d", rr, errno);
2007-04-06 01:56:28 +05:30
} /* net:ding */
/* if we're in "slowly" mode there's probably still stuff in the stdin
buffer, so don't read unless we really need MORE INPUT! MORE INPUT! */
if (rzleft)
goto shovel;
/* okay, suck more stdin */
if (pfds[0].revents) { /* stdin: ding! */
rr = read(STDIN_FILENO, bigbuf_in, BIGSIZ);
2007-04-06 01:56:28 +05:30
/* 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 ... */
pfds[0].fd = -1; /* disable stdin */
/*close(STDIN_FILENO); - not really necessary */
/* Let peer know we have no more data */
/* nc 1.10 doesn't do this: */
shutdown(netfd, SHUT_WR);
fds_open--;
2007-04-06 01:56:28 +05:30
} else {
rzleft = rr;
zp = bigbuf_in;
}
} /* stdin:ding */
shovel:
/* now that we've dingdonged all our thingdings, send off the results.
Geez, why does this look an awful lot like the big loop in "rsh"? ...
not sure if the order of this matters, but write net -> stdout first. */
if (rnleft) {
rr = write(STDOUT_FILENO, np, rnleft);
2007-04-06 01:56:28 +05:30
if (rr > 0) {
if (o_ofile) /* log the stdout */
oprint('<', (unsigned char *)np, rr);
np += rr;
rnleft -= rr;
wrote_out += rr; /* global count */
2007-04-06 01:56:28 +05:30
}
Debug("wrote %d to stdout, errno %d", rr, errno);
2007-04-06 01:56:28 +05:30
} /* rnleft */
if (rzleft) {
if (o_interval) /* in "slowly" mode ?? */
rr = findline(zp, rzleft);
else
rr = rzleft;
rr = write(netfd, zp, rr); /* one line, or the whole buffer */
if (rr > 0) {
if (o_ofile) /* log what got sent */
oprint('>', (unsigned char *)zp, rr);
2007-04-06 01:56:28 +05:30
zp += rr;
rzleft -= rr;
wrote_net += rr; /* global count */
2007-04-06 01:56:28 +05:30
}
Debug("wrote %d to net, errno %d", rr, errno);
2007-04-06 01:56:28 +05:30
} /* rzleft */
if (o_interval) { /* cycle between slow lines, or ... */
sleep(o_interval);
continue; /* ...with hairy loop... */
2007-04-06 01:56:28 +05:30
}
if (rzleft || rnleft) { /* shovel that shit till they ain't */
2007-04-06 01:56:28 +05:30
wretry--; /* none left, and get another load */
/* net write retries sometimes happen on UDP connections */
if (!wretry) { /* is something hung? */
holler_error("too many output retries");
return 1;
}
2007-04-06 01:56:28 +05:30
goto shovel;
}
} /* while (fds_open) */
2007-04-06 01:56:28 +05:30
/* XXX: maybe want a more graceful shutdown() here, or screw around with
linger times?? I suspect that I don't need to since I'm always doing
blocking reads and writes and my own manual "last ditch" efforts to read
the net again after a timeout. I haven't seen any screwups yet, but it's
not like my test network is particularly busy... */
close(netfd);
return 0;
} /* readwrite */
/* main: now we pull it all together... */
int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nc_main(int argc UNUSED_PARAM, char **argv)
2007-04-06 01:56:28 +05:30
{
char *str_p, *str_s;
IF_NC_EXTRA(char *str_i, *str_o;)
char *themdotted = themdotted; /* for compiler */
2007-04-06 01:56:28 +05:30
char **proggie;
int x;
unsigned cnt_l = 0;
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unsigned o_lport = 0;
INIT_G();
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/* catch a signal or two for cleanup */
bb_signals(0
+ (1 << SIGINT)
+ (1 << SIGQUIT)
+ (1 << SIGTERM)
, catch);
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/* and suppress others... */
bb_signals(0
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#ifdef SIGURG
+ (1 << SIGURG)
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#endif
+ (1 << SIGPIPE) /* important! */
, SIG_IGN);
2007-04-06 01:56:28 +05:30
proggie = argv;
while (*++proggie) {
if (strcmp(*proggie, "-e") == 0) {
*proggie = NULL;
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;
}
}
2007-04-06 01:56:28 +05:30
}
proggie = NULL;
e_found:
2007-05-30 05:59:55 +05:30
2007-04-06 01:56:28 +05:30
// -g -G -t -r deleted, unimplemented -a deleted too
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
getopt32(argv, "^"
"np:s:uvw:+"/* -w N */ IF_NC_SERVER("lk")
IF_NC_EXTRA("i:o:z")
"\0"
"?2:vv"IF_NC_SERVER(":ll"), /* max 2 params; -v and -l are counters */
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
&str_p, &str_s, &o_wait
IF_NC_EXTRA(, &str_i, &str_o)
, &o_verbose IF_NC_SERVER(, &cnt_l)
);
2007-04-06 01:56:28 +05:30
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
2007-04-06 01:56:28 +05:30
//if (option_mask32 & OPT_l) /* listen mode */
if (option_mask32 & OPT_k) /* persistent server mode */
cnt_l = 2;
#endif
2007-04-06 01:56:28 +05:30
//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 */
o_lport = bb_lookup_port(str_p, o_udpmode ? "udp" : "tcp", 0);
if (!o_lport)
bb_error_msg_and_die("bad local port '%s'", str_p);
}
//if (option_mask32 & OPT_r) /* randomize various things */
//if (option_mask32 & OPT_u) /* use UDP */
//if (option_mask32 & OPT_v) /* verbose */
//if (option_mask32 & OPT_w) /* wait time */
2007-04-06 01:56:28 +05:30
//if (option_mask32 & OPT_z) /* little or no data xfer */
/* We manage our fd's so that they are never 0,1,2 */
/*bb_sanitize_stdio(); - not needed */
2007-04-06 01:56:28 +05:30
if (argv[0]) {
themaddr = xhost2sockaddr(argv[0],
argv[1]
? bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0)
: 0);
}
2007-04-06 01:56:28 +05:30
/* create & bind network socket */
x = (o_udpmode ? SOCK_DGRAM : SOCK_STREAM);
2007-04-06 01:56:28 +05:30
if (option_mask32 & OPT_s) { /* local address */
/* if o_lport is still 0, then we will use random port */
2007-04-06 01:56:28 +05:30
ouraddr = xhost2sockaddr(str_s, o_lport);
#ifdef BLOAT
/* prevent spurious "UDP listen needs !0 port" */
o_lport = get_nport(ouraddr);
o_lport = ntohs(o_lport);
#endif
x = xsocket(ouraddr->u.sa.sa_family, x, 0);
2007-04-06 01:56:28 +05:30
} else {
/* We try IPv6, then IPv4, unless addr family is
* implicitly set by way of remote addr/port spec */
x = xsocket_type(&ouraddr,
(themaddr ? themaddr->u.sa.sa_family : AF_UNSPEC),
x);
2007-04-06 01:56:28 +05:30
if (o_lport)
set_nport(&ouraddr->u.sa, htons(o_lport));
2007-04-06 01:56:28 +05:30
}
xmove_fd(x, netfd);
2007-04-06 01:56:28 +05:30
setsockopt_reuseaddr(netfd);
if (o_udpmode)
socket_want_pktinfo(netfd);
if (!ENABLE_FEATURE_UNIX_LOCAL
|| cnt_l != 0 /* listen */
|| ouraddr->u.sa.sa_family != AF_UNIX
) {
xbind(netfd, &ouraddr->u.sa, ouraddr->len);
}
2007-04-06 01:56:28 +05:30
#if 0
setsockopt_SOL_SOCKET_int(netfd, SO_RCVBUF, o_rcvbuf);
setsockopt_SOL_SOCKET_int(netfd, SO_SNDBUF, o_sndbuf);
2007-04-06 01:56:28 +05:30
#endif
#ifdef BLOAT
if (OPT_l && (option_mask32 & (OPT_u|OPT_l)) == (OPT_u|OPT_l)) {
/* apparently UDP can listen ON "port 0",
but that's not useful */
if (!o_lport)
bb_error_msg_and_die("UDP listen needs nonzero -p port");
2007-04-06 01:56:28 +05:30
}
#endif
2007-04-06 01:56:28 +05:30
if (proggie) {
close(STDIN_FILENO); /* won't need stdin */
2007-04-06 01:56:28 +05:30
option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
}
#if ENABLE_NC_EXTRA
if (o_ofile)
xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd);
#endif
2007-04-06 01:56:28 +05:30
if (cnt_l != 0) {
dolisten((cnt_l - 1), proggie);
2007-04-06 01:56:28 +05:30
/* dolisten does its own connect reporting */
x = readwrite(); /* it even works with UDP! */
} else {
/* Outbound connects. Now we're more picky about args... */
if (!themaddr)
bb_show_usage();
2007-04-06 01:56:28 +05:30
remend = *themaddr;
if (o_verbose)
themdotted = xmalloc_sockaddr2dotted(&themaddr->u.sa);
2007-04-06 01:56:28 +05:30
x = connect_w_timeout(netfd);
if (o_zero && x == 0 && o_udpmode) /* if UDP scanning... */
x = udptest();
if (x == 0) { /* Yow, are we OPEN YET?! */
if (o_verbose)
fprintf(stderr, "%s (%s) open\n", argv[0], themdotted);
2007-04-06 01:56:28 +05:30
if (proggie) /* exec is valid for outbound, too */
doexec(proggie);
if (!o_zero)
x = readwrite();
} else { /* connect or udptest wasn't successful */
x = 1; /* exit status */
/* if we're scanning at a "one -v" verbosity level, don't print refusals.
Give it another -v if you want to see everything. */
if (o_verbose > 1 || (o_verbose && errno != ECONNREFUSED))
bb_perror_msg("%s (%s)", argv[0], themdotted);
2007-04-06 01:56:28 +05:30
}
}
if (o_verbose > 1) /* normally we don't care */
fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out);
return x;
}