*
* Copyright (C) 2007 Denys Vlasenko.
*
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
/* Author's comments from nc 1.10:
* - source routing
* - multiple DNS checks
* Functionalty which is different from nc 1.10:
- * - Prog in '-e prog' can have prog's parameters and options.
+ * - PROG in '-e PROG' can have ARGS (and options).
* Because of this -e option must be last.
- * - nc doesn't redirect stderr to the network socket for the -e prog.
+//TODO: remove -e incompatibility?
+ * - we don't redirect stderr to the network socket for the -e PROG.
+ * (PROG can do it itself if needed, but sometimes it is NOT wanted!)
* - numeric addresses are printed in (), not [] (IPv6 looks better),
* port numbers are inside (): (1.2.3.4:5678)
* - network read errors are reported on verbose levels > 1
* (nc 1.10 treats them as EOF)
* - TCP connects from wrong ip/ports (if peer ip:port is specified
* on the command line, but accept() says that it came from different addr)
- * are closed, but nc doesn't exit - continues to listen/accept.
+ * are closed, but we don't exit - we continue to listen/accept.
+ * 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.
*/
/* done in nc.c: #include "libbb.h" */
+//usage:#if ENABLE_NC_110_COMPAT
+//usage:
+//usage:#define nc_trivial_usage
+//usage: "[OPTIONS] HOST PORT - connect"
+//usage: IF_NC_SERVER("\n"
+//usage: "nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen"
+//usage: )
+//usage:#define nc_full_usage "\n\n"
+//usage: " -e PROG Run PROG after connect (must be last)"
+//usage: IF_NC_SERVER(
+//usage: "\n -l Listen mode, for inbound connects"
+//usage: "\n -lk With -e, provides persistent server"
+/* -ll does the same as -lk, but its our extension, while -k is BSD'd,
+ * presumably more widely known. Therefore we advertise it, not -ll.
+ * I would like to drop -ll support, but our "small" nc supports it,
+ * and Rob uses it.
+ */
+//usage: )
+//usage: "\n -p PORT Local port"
+//usage: "\n -s ADDR Local address"
+//usage: "\n -w SEC Timeout for connects and final net reads"
+//usage: IF_NC_EXTRA(
+//usage: "\n -i SEC Delay interval for lines sent" /* ", ports scanned" */
+//usage: )
+//usage: "\n -n Don't do DNS resolution"
+//usage: "\n -u UDP mode"
+//usage: "\n -v Verbose"
+//usage: IF_NC_EXTRA(
+//usage: "\n -o FILE Hex dump traffic"
+//usage: "\n -z Zero-I/O mode (scanning)"
+//usage: )
+//usage:#endif
+
+/* "\n -r Randomize local and remote ports" */
+/* "\n -g gateway Source-routing hop point[s], up to 8" */
+/* "\n -G num Source-routing pointer: 4, 8, 12, ..." */
+/* "\nport numbers can be individual or ranges: lo-hi [inclusive]" */
+
+/* -e PROG can take ARGS too: "nc ... -e ls -l", but we don't document it
+ * in help text: nc 1.10 does not allow that. We don't want to entice
+ * users to use this incompatibility */
+
enum {
SLEAZE_PORT = 31337, /* for UDP-scan RTT trick, change if ya want */
BIGSIZ = 8192, /* big buffers */
unsigned wrote_out; /* total stdout bytes */
unsigned wrote_net; /* total net bytes */
#endif
+ char *proggie0saved;
/* ouraddr is never NULL and goes through three states as we progress:
1 - local address before bind (IP/port possibly zero)
2 - local address after bind (port is nonzero)
jmp_buf jbuf; /* timer crud */
- /* will malloc up the following globals: */
- fd_set ding1; /* for select loop */
- fd_set ding2;
char bigbuf_in[BIGSIZ]; /* data buffers */
char bigbuf_net[BIGSIZ];
};
#define themaddr (G.themaddr )
#define remend (G.remend )
#define jbuf (G.jbuf )
-#define ding1 (G.ding1 )
-#define ding2 (G.ding2 )
#define bigbuf_in (G.bigbuf_in )
#define bigbuf_net (G.bigbuf_net)
#define o_verbose (G.o_verbose )
/* Must match getopt32 call! */
enum {
- OPT_h = (1 << 0),
- OPT_n = (1 << 1),
- OPT_p = (1 << 2),
- OPT_s = (1 << 3),
- OPT_u = (1 << 4),
- OPT_v = (1 << 5),
- OPT_w = (1 << 6),
- OPT_l = (1 << 7) * ENABLE_NC_SERVER,
- OPT_i = (1 << (7+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
- OPT_o = (1 << (8+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
- OPT_z = (1 << (9+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA,
+ OPT_n = (1 << 0),
+ OPT_p = (1 << 1),
+ OPT_s = (1 << 2),
+ OPT_u = (1 << 3),
+ OPT_v = (1 << 4),
+ OPT_w = (1 << 5),
+ OPT_l = (1 << 6) * ENABLE_NC_SERVER,
+ OPT_k = (1 << 7) * ENABLE_NC_SERVER,
+ OPT_i = (1 << (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,
};
#define o_nflag (option_mask32 & OPT_n)
#define o_udpmode (option_mask32 & OPT_u)
-#if ENABLE_NC_SERVER
-#define o_listen (option_mask32 & OPT_l)
-#else
-#define o_listen 0
-#endif
#if ENABLE_NC_EXTRA
#define o_ofile (option_mask32 & OPT_o)
#define o_zero (option_mask32 & OPT_z)
#define Debug(...) do { } while (0)
#endif
-#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)
+#define holler_error(msg) do { if (o_verbose) bb_simple_error_msg(msg); } while (0)
+#define holler_perror(msg) do { if (o_verbose) bb_simple_perror_msg(msg); } while (0)
/* catch: no-brainer interrupt handler */
static void catch(int sig)
static int doexec(char **proggie) NORETURN;
static int doexec(char **proggie)
{
+ if (G.proggie0saved)
+ proggie[0] = G.proggie0saved;
xmove_fd(netfd, 0);
dup2(0, 1);
/* dup2(0, 2); - do we *really* want this? NO!
* exec'ed prog can do it yourself, if needed */
- execvp(proggie[0], proggie);
- bb_perror_msg_and_die("can't execute '%s'", proggie[0]);
+ BB_EXECVP_or_die(proggie);
}
/* connect_w_timeout:
incoming and returns an open connection *from* someplace. If we were
given host/port args, any connections from elsewhere are rejected. This
in conjunction with local-address binding should limit things nicely... */
-static void dolisten(void)
+static void dolisten(int is_persistent, char **proggie)
{
int rr;
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");
+ bb_simple_perror_msg_and_die("recvfrom");
unarm();
} else
- bb_error_msg_and_die("timeout");
+ bb_simple_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):
xconnect(netfd, &remend.u.sa, ouraddr->len);
} else {
/* TCP */
+ another:
arm(o_wait); /* wrap this in a timer, too; 0 = forever */
if (setjmp(jbuf) == 0) {
again:
remend.len = LSA_SIZEOF_SA;
rr = accept(netfd, &remend.u.sa, &remend.len);
if (rr < 0)
- bb_perror_msg_and_die("accept");
+ bb_simple_perror_msg_and_die("accept");
if (themaddr) {
int sv_port, port, r;
if (port == 0) {
/* "nc -nl -p LPORT RHOST" (w/o RPORT!):
* we should accept any remote port */
- set_nport(&remend, 0); /* blot out remote port# */
+ set_nport(&remend.u.sa, 0); /* blot out remote port# */
}
r = memcmp(&remend.u.sa, &themaddr->u.sa, remend.len);
- set_nport(&remend, sv_port); /* restore */
+ 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 */
}
unarm();
} else
- bb_error_msg_and_die("timeout");
+ bb_simple_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
rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x);
if (rr >= 0 && x) { /* we've got options, lessee em... */
- bin2hex(bigbuf_net, optbuf, x);
- bigbuf_net[2*x] = '\0';
+ *bin2hex(bigbuf_net, optbuf, x) = '\0';
fprintf(stderr, "IP options: %s\n", bigbuf_net);
}
#endif
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 undesireable ones by closing.
+ accept the connection and then reject undesirable ones by closing.
In other words, we need a TCP MSG_PEEK. */
/* bbox: removed most of it */
lcladdr = xmalloc_sockaddr2dotted(&ouraddr->u.sa);
if (!o_nflag)
free(remhostname);
}
+
+ if (proggie)
+ doexec(proggie);
}
/* udptest:
rr = write(netfd, bigbuf_in, 1);
if (rr != 1)
- bb_perror_msg("udptest first write");
+ bb_simple_perror_msg("udptest first write");
if (o_wait)
sleep(o_wait); // can be interrupted! while (t) nanosleep(&t)?
/* 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 doesnt cause
+ /* Set a temporary connect timeout, so packet filtration doesn't cause
us to hang forever, and hit it */
o_wait = 5; /* enough that we'll notice?? */
rr = xsocket(ouraddr->u.sa.sa_family, SOCK_STREAM, 0);
- set_nport(themaddr, htons(SLEAZE_PORT));
+ set_nport(&themaddr->u.sa, htons(SLEAZE_PORT));
connect_w_timeout(rr);
/* don't need to restore themaddr's port, it's not used anymore */
close(rr);
#endif
/* readwrite:
- handle stdin/stdout/network I/O. Bwahaha!! -- the select loop from hell.
+ handle stdin/stdout/network I/O. Bwahaha!! -- the i/o loop from hell.
In this instance, return what might become our exit status. */
static int readwrite(void)
{
- int rr;
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 wretry; /* net-write sanity counter */
- unsigned wfirst; /* one-shot flag to skip first net read */
+ unsigned fds_open;
- /* if you don't have all this FD_* macro hair in sys/types.h, you'll have to
- either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */
- FD_SET(netfd, &ding1); /* global: the net is open */
+ struct pollfd pfds[2];
+ pfds[0].fd = STDIN_FILENO;
+ pfds[0].events = POLLIN;
+ pfds[1].fd = netfd;
+ pfds[1].events = POLLIN;
+
+ fds_open = 2;
netretry = 2;
- wfirst = 0;
rzleft = rnleft = 0;
if (o_interval)
sleep(o_interval); /* pause *before* sending stuff, too */
- errno = 0; /* clear from sleep, close, whatever */
- /* and now the big ol' select shoveling loop ... */
- while (FD_ISSET(netfd, &ding1)) { /* i.e. till the *net* closes! */
- wretry = 8200; /* more than we'll ever hafta write */
- if (wfirst) { /* any saved stdin buffer? */
- wfirst = 0; /* clear flag for the duration */
- goto shovel; /* and go handle it first */
- }
- ding2 = ding1; /* FD_COPY ain't portable... */
- /* some systems, notably linux, crap into their select timers on return, so
- we create a expendable copy and give *that* to select. */
+ /* 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;
if (o_wait) {
- struct timeval tmp_timer;
- tmp_timer.tv_sec = o_wait;
- tmp_timer.tv_usec = 0;
- /* highest possible fd is netfd (3) */
- rr = select(netfd+1, &ding2, NULL, NULL, &tmp_timer);
- } else
- rr = select(netfd+1, &ding2, NULL, NULL, NULL);
+ poll_tmout_ms = INT_MAX;
+ if (o_wait < INT_MAX / 1000)
+ poll_tmout_ms = o_wait * 1000;
+ }
+ rr = poll(pfds, 2, poll_tmout_ms);
if (rr < 0 && errno != EINTR) { /* might have gotten ^Zed, etc */
- holler_perror("select");
+ holler_perror("poll");
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 (!FD_ISSET(STDIN_FILENO, &ding1))
+ if (!pfds[0].revents) {
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);
- return 0; /* not an error! */
+ 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! */
+ }
}
- } /* select timeout */
- /* xxx: should we check the exception fds too? The read fds seem to give
- us the right info, and none of the examples I found bothered. */
+ } /* timeout */
/* Ding!! Something arrived, go check all the incoming hoppers, net first */
- if (FD_ISSET(netfd, &ding2)) { /* net: ding! */
+ if (pfds[1].revents) { /* net: ding! */
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");
+ bb_simple_perror_msg("net read");
}
- FD_CLR(netfd, &ding1); /* net closed, we'll finish up... */
+ pfds[1].fd = -1; /* don't poll for netfd anymore */
+ fds_open--;
rzleft = 0; /* can't write anymore: broken pipe */
} else {
rnleft = rr;
goto shovel;
/* okay, suck more stdin */
- if (FD_ISSET(STDIN_FILENO, &ding2)) { /* stdin: ding! */
+ if (pfds[0].revents) { /* stdin: ding! */
rr = read(STDIN_FILENO, bigbuf_in, BIGSIZ);
/* Considered making reads here smaller for UDP mode, but 8192-byte
mobygrams are kinda fun and exercise the reassembler. */
if (rr <= 0) { /* at end, or fukt, or ... */
- FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */
- close(STDIN_FILENO);
-// Does it make sense to shutdown(net_fd, SHUT_WR)
-// to let other side know that we won't write anything anymore?
-// (and what about keeping compat if we do that?)
+ 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--;
} else {
rzleft = rr;
zp = bigbuf_in;
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. */
- /* sanity check. Works because they're both unsigned... */
- if ((rzleft > 8200) || (rnleft > 8200)) {
- holler_error("bogus buffers: %u, %u", rzleft, rnleft);
- rzleft = rnleft = 0;
- }
- /* net write retries sometimes happen on UDP connections */
- if (!wretry) { /* is something hung? */
- holler_error("too many output retries");
- return 1;
- }
if (rnleft) {
rr = write(STDOUT_FILENO, np, rnleft);
if (rr > 0) {
if (o_ofile) /* log the stdout */
oprint('<', (unsigned char *)np, rr);
- np += rr; /* fix up ptrs and whatnot */
- rnleft -= rr; /* will get sanity-checked above */
- wrote_out += rr; /* global count */
+ np += rr;
+ rnleft -= rr;
+ wrote_out += rr; /* global count */
}
Debug("wrote %d to stdout, errno %d", rr, errno);
} /* rnleft */
oprint('>', (unsigned char *)zp, rr);
zp += rr;
rzleft -= rr;
- wrote_net += rr; /* global count */
+ wrote_net += rr; /* global count */
}
Debug("wrote %d to net, errno %d", rr, errno);
} /* rzleft */
if (o_interval) { /* cycle between slow lines, or ... */
sleep(o_interval);
- errno = 0; /* clear from sleep */
- continue; /* ...with hairy select loop... */
+ continue; /* ...with hairy loop... */
}
- if ((rzleft) || (rnleft)) { /* shovel that shit till they ain't */
+ if (rzleft || rnleft) { /* shovel that shit till they ain't */
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;
+ }
goto shovel;
}
- } /* while ding1:netfd is open */
+ } /* while (fds_open) */
/* 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
{
char *str_p, *str_s;
IF_NC_EXTRA(char *str_i, *str_o;)
- char *themdotted = themdotted; /* gcc */
+ char *themdotted = themdotted; /* for compiler */
char **proggie;
int x;
+ unsigned cnt_l = 0;
unsigned o_lport = 0;
INIT_G();
proggie++;
goto e_found;
}
+ /* -<other_opts>e PROG [ARGS] ? */
+ /* (aboriginal linux uses this form) */
+ if (proggie[0][0] == '-') {
+ char *optpos = *proggie + 1;
+ /* Skip all valid opts w/o params */
+ optpos = optpos + strspn(optpos, "nuv"IF_NC_SERVER("lk")IF_NC_EXTRA("z"));
+ if (*optpos == 'e' && !optpos[1]) {
+ *optpos = '\0';
+ proggie++;
+ G.proggie0saved = *proggie;
+ *proggie = NULL; /* terminate argv for getopt32 */
+ goto e_found;
+ }
+ }
}
proggie = NULL;
e_found:
// -g -G -t -r deleted, unimplemented -a deleted too
- opt_complementary = "?2:vv:w+"; /* max 2 params; -v is a counter; -w N */
- getopt32(argv, "hnp:s:uvw:" IF_NC_SERVER("l")
- IF_NC_EXTRA("i:o:z"),
- &str_p, &str_s, &o_wait
- IF_NC_EXTRA(, &str_i, &str_o, &o_verbose));
+ 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 */
+ &str_p, &str_s, &o_wait
+ IF_NC_EXTRA(, &str_i, &str_o)
+ , &o_verbose IF_NC_SERVER(, &cnt_l)
+ );
argv += optind;
#if ENABLE_NC_EXTRA
if (option_mask32 & OPT_i) /* line-interval time */
o_interval = xatou_range(str_i, 1, 0xffff);
#endif
+#if ENABLE_NC_SERVER
//if (option_mask32 & OPT_l) /* listen mode */
+ if (option_mask32 & OPT_k) /* persistent server mode */
+ cnt_l = 2;
+#endif
//if (option_mask32 & OPT_n) /* numeric-only, no DNS lookups */
//if (option_mask32 & OPT_o) /* hexdump log */
if (option_mask32 & OPT_p) { /* local source port */
(themaddr ? themaddr->u.sa.sa_family : AF_UNSPEC),
x);
if (o_lport)
- set_nport(ouraddr, htons(o_lport));
+ set_nport(&ouraddr->u.sa, htons(o_lport));
}
xmove_fd(x, netfd);
setsockopt_reuseaddr(netfd);
if (o_udpmode)
socket_want_pktinfo(netfd);
if (!ENABLE_FEATURE_UNIX_LOCAL
- || o_listen
+ || cnt_l != 0 /* listen */
|| ouraddr->u.sa.sa_family != AF_UNIX
) {
xbind(netfd, &ouraddr->u.sa, ouraddr->len);
}
#if 0
- setsockopt(netfd, SOL_SOCKET, SO_RCVBUF, &o_rcvbuf, sizeof o_rcvbuf);
- setsockopt(netfd, SOL_SOCKET, SO_SNDBUF, &o_sndbuf, sizeof o_sndbuf);
+ setsockopt_SOL_SOCKET_int(netfd, SO_RCVBUF, o_rcvbuf);
+ setsockopt_SOL_SOCKET_int(netfd, SO_SNDBUF, o_sndbuf);
#endif
#ifdef BLOAT
/* 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");
+ bb_simple_error_msg_and_die("UDP listen needs nonzero -p port");
}
#endif
- FD_SET(STDIN_FILENO, &ding1); /* stdin *is* initially open */
if (proggie) {
- close(0); /* won't need stdin */
+ close(STDIN_FILENO); /* won't need stdin */
option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
}
#if ENABLE_NC_EXTRA
xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd);
#endif
- if (o_listen) {
- dolisten();
+ if (cnt_l != 0) {
+ dolisten((cnt_l - 1), proggie);
/* dolisten does its own connect reporting */
- if (proggie) /* -e given? */
- doexec(proggie);
x = readwrite(); /* it even works with UDP! */
} else {
/* Outbound connects. Now we're more picky about args... */
if (!themaddr)
- bb_error_msg_and_die("no destination");
+ bb_show_usage();
remend = *themaddr;
if (o_verbose)
projects / oweals / busybox.git / blobdiff