mirror of
https://github.com/Ponce/slackbuilds
synced 2024-10-22 22:27:28 +02:00
b49d0a636b
Apply the patches locally and added a note about this package being incompatible with nc from Slackware Signed-off-by: Matteo Bernardini <ponce@slackbuilds.org>
457 lines
13 KiB
Diff
457 lines
13 KiB
Diff
From: Aron Xu <aron@debian.org>
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Date: Mon, 13 Feb 2012 19:06:52 +0800
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Subject: misc connection failures
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---
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nc.1 | 76 ++++++++++++++++++++++++++++++++++++---
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netcat.c | 119 ++++++++++++++++++++++++++++++++++++++++++--------------------
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2 files changed, 153 insertions(+), 42 deletions(-)
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diff --git a/nc.1 b/nc.1
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index 60e3668..477cb1b 100644
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--- a/nc.1
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+++ b/nc.1
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@@ -34,7 +34,7 @@
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.Sh SYNOPSIS
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.Nm nc
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.Bk -words
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-.Op Fl 46CDdhklnrStUuvZz
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+.Op Fl 46bCDdhklnrStUuvZz
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.Op Fl I Ar length
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.Op Fl i Ar interval
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.Op Fl O Ar length
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@@ -99,6 +99,8 @@ to use IPv4 addresses only.
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Forces
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.Nm
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to use IPv6 addresses only.
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+.It Fl b
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+Allow broadcast.
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.It Fl C
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Send CRLF as line-ending.
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.It Fl D
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@@ -323,6 +325,54 @@ and which side is being used as a
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The connection may be terminated using an
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.Dv EOF
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.Pq Sq ^D .
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+.Pp
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+There is no
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+.Fl c
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+or
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+.Fl e
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+option in this netcat, but you still can execute a command after connection
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+being established by redirecting file descriptors. Be cautious here because
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+opening a port and let anyone connected execute arbitrary command on your
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+site is DANGEROUS. If you really need to do this, here is an example:
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+.Pp
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+On
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+.Sq server
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+side:
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+.Pp
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+.Dl $ rm -f /tmp/f; mkfifo /tmp/f
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+.Dl $ cat /tmp/f | /bin/sh -i 2>&1 | nc -l 127.0.0.1 1234 > /tmp/f
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+.Pp
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+On
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+.Sq client
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+side:
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+.Pp
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+.Dl $ nc host.example.com 1234
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+.Dl $ (shell prompt from host.example.com)
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+.Pp
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+By doing this, you create a fifo at /tmp/f and make nc listen at port 1234
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+of address 127.0.0.1 on
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+.Sq server
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+side, when a
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+.Sq client
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+establishes a connection successfully to that port, /bin/sh gets executed
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+on
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+.Sq server
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+side and the shell prompt is given to
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+.Sq client
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+side.
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+.Pp
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+When connection is terminated,
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+.Nm
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+quits as well. Use
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+.Fl k
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+if you want it keep listening, but if the command quits this option won't
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+restart it or keep
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+.Nm
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+running. Also don't forget to remove the file descriptor once you don't need
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+it anymore:
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+.Pp
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+.Dl $ rm -f /tmp/f
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+.Pp
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.Sh DATA TRANSFER
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The example in the previous section can be expanded to build a
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basic data transfer model.
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@@ -382,15 +432,30 @@ The
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flag can be used to tell
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.Nm
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to report open ports,
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-rather than initiate a connection.
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+rather than initiate a connection. Usually it's useful to turn on verbose
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+output to stderr by use this option in conjunction with
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+.Fl v
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+option.
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+.Pp
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For example:
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.Bd -literal -offset indent
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-$ nc -z host.example.com 20-30
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+$ nc \-zv host.example.com 20-30
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Connection to host.example.com 22 port [tcp/ssh] succeeded!
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Connection to host.example.com 25 port [tcp/smtp] succeeded!
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.Ed
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.Pp
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-The port range was specified to limit the search to ports 20 \- 30.
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+The port range was specified to limit the search to ports 20 \- 30, and is
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+scanned by increasing order.
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+.Pp
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+You can also specify a list of ports to scan, for example:
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+.Bd -literal -offset indent
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+$ nc \-zv host.example.com 80 20 22
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+nc: connect to host.example.com 80 (tcp) failed: Connection refused
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+nc: connect to host.example.com 20 (tcp) failed: Connection refused
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+Connection to host.example.com port [tcp/ssh] succeeded!
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+.Ed
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+.Pp
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+The ports are scanned by the order you given.
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.Pp
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Alternatively, it might be useful to know which server software
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is running, and which versions.
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@@ -455,6 +520,9 @@ Original implementation by *Hobbit*
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.br
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Rewritten with IPv6 support by
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.An Eric Jackson Aq ericj@monkey.org .
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+.br
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+Modified for Debian port by Aron Xu
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+.Aq aron@debian.org .
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.Sh CAVEATS
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UDP port scans using the
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.Fl uz
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diff --git a/netcat.c b/netcat.c
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index bf9940f..c938d11 100644
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--- a/netcat.c
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+++ b/netcat.c
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@@ -88,6 +88,7 @@
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#include <netdb.h>
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#include <poll.h>
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#include <signal.h>
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+#include <stddef.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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@@ -115,6 +116,7 @@
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#define UDP_SCAN_TIMEOUT 3 /* Seconds */
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/* Command Line Options */
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+int bflag; /* Allow Broadcast */
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int Cflag = 0; /* CRLF line-ending */
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int dflag; /* detached, no stdin */
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unsigned int iflag; /* Interval Flag */
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@@ -146,7 +148,7 @@ char *portlist[PORT_MAX+1];
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char *unix_dg_tmp_socket;
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void atelnet(int, unsigned char *, unsigned int);
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-void build_ports(char *);
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+void build_ports(char **);
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void help(void);
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int local_listen(char *, char *, struct addrinfo);
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void readwrite(int);
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@@ -171,11 +173,14 @@ int
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main(int argc, char *argv[])
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{
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int ch, s, ret, socksv;
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- char *host, *uport;
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+ char *host, **uport;
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struct addrinfo hints;
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struct servent *sv;
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socklen_t len;
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- struct sockaddr_storage cliaddr;
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+ union {
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+ struct sockaddr_storage storage;
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+ struct sockaddr_un forunix;
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+ } cliaddr;
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char *proxy = NULL;
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const char *errstr, *proxyhost = "", *proxyport = NULL;
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struct addrinfo proxyhints;
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@@ -189,7 +194,7 @@ main(int argc, char *argv[])
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sv = NULL;
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while ((ch = getopt(argc, argv,
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- "46CDdhI:i:jklnO:P:p:q:rSs:tT:UuV:vw:X:x:Zz")) != -1) {
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+ "46bCDdhI:i:jklnO:P:p:q:rSs:tT:UuV:vw:X:x:Zz")) != -1) {
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switch (ch) {
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case '4':
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family = AF_INET;
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@@ -197,6 +202,13 @@ main(int argc, char *argv[])
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case '6':
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family = AF_INET6;
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break;
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+ case 'b':
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+# if defined(SO_BROADCAST)
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+ bflag = 1;
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+# else
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+ errx(1, "no broadcast frame support available");
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+# endif
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+ break;
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case 'U':
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family = AF_UNIX;
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break;
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@@ -342,35 +354,40 @@ main(int argc, char *argv[])
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/* Cruft to make sure options are clean, and used properly. */
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if (argv[0] && !argv[1] && family == AF_UNIX) {
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- if (uflag)
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- errx(1, "cannot use -u and -U");
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# if defined(IPPROTO_DCCP) && defined(SOCK_DCCP)
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if (dccpflag)
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errx(1, "cannot use -Z and -U");
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# endif
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host = argv[0];
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uport = NULL;
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- } else if (!argv[0] && lflag) {
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- if (sflag)
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- errx(1, "cannot use -s and -l");
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- if (zflag)
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- errx(1, "cannot use -z and -l");
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- if (pflag)
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- uport=pflag;
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- } else if (!lflag && kflag) {
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- errx(1, "cannot use -k without -l");
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- } else if (argv[0] && !argv[1]) {
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- if (!lflag)
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- usage(1);
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- uport = argv[0];
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+ } else if (argv[0] && !argv[1] && lflag) {
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+ if (pflag) {
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+ uport = &pflag;
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+ host = argv[0];
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+ } else {
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+ uport = argv;
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+ host = NULL;
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+ }
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+ } else if (!argv[0] && lflag && pflag) {
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+ uport = &pflag;
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host = NULL;
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} else if (argv[0] && argv[1]) {
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host = argv[0];
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- uport = argv[1];
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+ uport = &argv[1];
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} else
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usage(1);
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-
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+ if (lflag) {
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+ if (sflag)
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+ errx(1, "cannot use -s and -l");
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+ if (zflag)
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+ errx(1, "cannot use -z and -l");
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+ if (pflag)
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+ /* This still does not work well because of getopt mess
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+ errx(1, "cannot use -p and -l"); */
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+ uport = &pflag;
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+ } else if (!lflag && kflag)
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+ errx(1, "cannot use -k without -l");
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/* Get name of temporary socket for unix datagram client */
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if ((family == AF_UNIX) && uflag && !lflag) {
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@@ -448,7 +465,7 @@ main(int argc, char *argv[])
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else
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s = unix_listen(host);
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} else
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- s = local_listen(host, uport, hints);
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+ s = local_listen(host, *uport, hints);
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if (s < 0)
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err(1, NULL);
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@@ -457,7 +474,8 @@ main(int argc, char *argv[])
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local = ":::";
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else
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local = "0.0.0.0";
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- fprintf(stderr, "Listening on [%s] (family %d, port %d)\n",
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+ if (vflag && (family != AF_UNIX))
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+ fprintf(stderr, "Listening on [%s] (family %d, port %s)\n",
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host ?: local,
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family,
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*uport);
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@@ -490,13 +508,17 @@ main(int argc, char *argv[])
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len = sizeof(cliaddr);
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connfd = accept(s, (struct sockaddr *)&cliaddr,
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&len);
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- if(vflag) {
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+ if(vflag && family == AF_UNIX) {
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+ fprintf(stderr, "Connection from \"%.*s\" accepted\n",
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+ (len - (int)offsetof(struct sockaddr_un, sun_path)),
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+ ((struct sockaddr_un*)&cliaddr)->sun_path);
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+ } else if(vflag) {
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char *proto = proto_name(uflag, dccpflag);
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/* Don't look up port if -n. */
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if (nflag)
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sv = NULL;
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else
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- sv = getservbyport(ntohs(atoi(uport)),
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+ sv = getservbyport(ntohs(atoi(*uport)),
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proto);
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if (((struct sockaddr *)&cliaddr)->sa_family == AF_INET) {
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@@ -504,7 +526,7 @@ main(int argc, char *argv[])
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inet_ntop(((struct sockaddr *)&cliaddr)->sa_family,&(((struct sockaddr_in *)&cliaddr)->sin_addr),dst,INET_ADDRSTRLEN);
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fprintf(stderr, "Connection from [%s] port %s [%s/%s] accepted (family %d, sport %d)\n",
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dst,
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- uport,
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+ *uport,
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proto,
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sv ? sv->s_name : "*",
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((struct sockaddr *)(&cliaddr))->sa_family,
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@@ -515,7 +537,7 @@ main(int argc, char *argv[])
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inet_ntop(((struct sockaddr *)&cliaddr)->sa_family,&(((struct sockaddr_in6 *)&cliaddr)->sin6_addr),dst,INET6_ADDRSTRLEN);
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fprintf(stderr, "Connection from [%s] port %s [%s/%s] accepted (family %d, sport %d)\n",
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dst,
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- uport,
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+ *uport,
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proto,
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sv ? sv->s_name : "*",
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((struct sockaddr *)&cliaddr)->sa_family,
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@@ -523,17 +545,21 @@ main(int argc, char *argv[])
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}
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else {
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fprintf(stderr, "Connection from unknown port %s [%s/%s] accepted (family %d, sport %d)\n",
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- uport,
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+ *uport,
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proto,
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sv ? sv->s_name : "*",
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((struct sockaddr *)(&cliaddr))->sa_family,
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ntohs(((struct sockaddr_in *)&cliaddr)->sin_port));
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}
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}
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+ if(!kflag)
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+ close(s);
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readwrite(connfd);
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close(connfd);
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}
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+ if (vflag && kflag)
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+ fprintf(stderr, "Connection closed, listening again.\n");
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if (kflag)
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continue;
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if (family != AF_UNIX) {
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@@ -641,6 +667,8 @@ unix_bind(char *path)
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return (-1);
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}
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+ unlink(path);
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+
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if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
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close(s);
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return (-1);
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@@ -662,8 +690,10 @@ unix_connect(char *path)
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if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
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return (-1);
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} else {
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- if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
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+ if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
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+ errx(1,"create unix socket failed");
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return (-1);
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+ }
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}
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(void)fcntl(s, F_SETFD, 1);
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@@ -674,9 +704,11 @@ unix_connect(char *path)
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sizeof(sun.sun_path)) {
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close(s);
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errno = ENAMETOOLONG;
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+ warn("unix connect abandoned");
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return (-1);
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}
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if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
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+ warn("unix connect failed");
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close(s);
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return (-1);
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}
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@@ -1105,22 +1137,23 @@ atelnet(int nfd, unsigned char *buf, unsigned int size)
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* that we should try to connect to.
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*/
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void
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-build_ports(char *p)
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+build_ports(char **p)
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{
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struct servent *sv;
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const char *errstr;
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char *n;
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int hi, lo, cp;
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int x = 0;
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+ int i;
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char *proto = proto_name(uflag, dccpflag);
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- sv = getservbyname(p, proto);
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+ sv = getservbyname(*p, proto);
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if (sv) {
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portlist[0] = calloc(1, PORT_MAX_LEN);
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if (portlist[0] == NULL)
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err(1, NULL);
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snprintf(portlist[0], PORT_MAX_LEN, "%d", ntohs(sv->s_port));
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- } else if ((n = strchr(p, '-')) != NULL) {
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+ } else if ((n = strchr(*p, '-')) != NULL) {
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*n = '\0';
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n++;
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@@ -1128,9 +1161,9 @@ build_ports(char *p)
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hi = strtonum(n, 1, PORT_MAX, &errstr);
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if (errstr)
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errx(1, "port number %s: %s", errstr, n);
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- lo = strtonum(p, 1, PORT_MAX, &errstr);
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+ lo = strtonum(*p, 1, PORT_MAX, &errstr);
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if (errstr)
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- errx(1, "port number %s: %s", errstr, p);
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+ errx(1, "port number %s: %s", errstr, *p);
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if (lo > hi) {
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cp = hi;
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@@ -1160,10 +1193,12 @@ build_ports(char *p)
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}
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}
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} else {
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- hi = strtonum(p, 1, PORT_MAX, &errstr);
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+ hi = strtonum(*p, 1, PORT_MAX, &errstr);
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if (errstr)
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- errx(1, "port number %s: %s", errstr, p);
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- portlist[0] = strdup(p);
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+ errx(1, "port number %s: %s", errstr, *p);
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+ for (i=0;p[i];i++) {
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+ portlist[i] = strdup(p[i]);
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+ }
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if (portlist[0] == NULL)
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err(1, NULL);
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}
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@@ -1198,6 +1233,13 @@ set_common_sockopts(int s)
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{
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int x = 1;
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+# if defined(SO_BROADCAST)
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+ if (bflag) {
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+ if (setsockopt(s, IPPROTO_TCP, SO_BROADCAST,
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+ &x, sizeof(x)) == -1)
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+ err(1, NULL);
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+ }
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+# endif
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# if defined(TCP_MD5SIG)
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if (Sflag) {
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if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
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@@ -1293,6 +1335,7 @@ help(void)
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fprintf(stderr, "\tCommand Summary:\n\
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\t-4 Use IPv4\n\
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\t-6 Use IPv6\n\
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+ \t-b Allow broadcast\n\
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\t-C Send CRLF as line-ending\n\
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\t-D Enable the debug socket option\n\
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\t-d Detach from stdin\n\
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@@ -1329,7 +1372,7 @@ void
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usage(int ret)
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{
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fprintf(stderr,
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- "usage: nc [-46CDdhjklnrStUuvZz] [-I length] [-i interval] [-O length]\n"
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+ "usage: nc [-46bCDdhjklnrStUuvZz] [-I length] [-i interval] [-O length]\n"
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"\t [-P proxy_username] [-p source_port] [-q seconds] [-s source]\n"
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"\t [-T toskeyword] [-V rtable] [-w timeout] [-X proxy_protocol]\n"
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"\t [-x proxy_address[:port]] [destination] [port]\n");
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--
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