I have a Perl script to run some commands on remote equipment by Net::Telnet. Sometimes, telnet session would be disconnected by remote side because login timeout or other cause. I want to know how I can check telnet session is still live before send next command? Thanks a lot!
my $tc = new Net::Telnet{Host=>$host,Port=>23};
sub checkTelnetLive { ??? }
my #commands=($cmd1,$cmd2,...);
foreach $cmd(#commands) {
if checkTelnetLive {
$tc->put($cmd);
$tc->waitfor('/COMPLD/');
}
else {
die "Remote equipment has disconnected session."
}
}
my $tc = new Net::Telnet (Host=> $host, Port=>23, Errmode => 'return' );
or you can use eval
eval {
my $tc = new Net::Telnet (Host=> $host, Port=>23, Errmode => 'return' );
#. plus other code
};
warn $# if $#;
Related
I'm working on moving a Perl script that pushed commands to routers. We have turned off telnet, so I'm working on getting SSH to work. After looking at a number of SSH libraries in Perl, I've opted to use Net::OpenSSH. I have no problem logging in and passing commands to the routers, but the problem I'm having is with entering config mode and subsequently passing a command.
The problem is that with each command entered, the underlying system appears to logout then reenter with the next subsequent command. For example with a Juniper router I'm trying to do the following:
edit private
set interfaces xe-1/3/2 description "AVAIL: SOMETHING GOES HERE"
commit
exit
quit
Tailing the syslog from the router I'm seeing something like this...
(...)
UI_LOGIN_EVENT: User 'tools' login, class 'j-remote-user' [65151], ssh-connection 'xxx.xxx.xxx.xxx 42247 xxx.xxx.xxx.xxx 22', client-mode 'cli'
UI_CMDLINE_READ_LINE: User 'tools', command 'edit private '
UI_DBASE_LOGIN_EVENT: User 'tools' entering configuration mode
UI_DBASE_LOGOUT_EVENT: User 'tools' exiting configuration mode
UI_LOGOUT_EVENT: User 'tools' logout
UI_AUTH_EVENT: Authenticated user 'remote' at permission level 'j-remote-user'
UI_LOGIN_EVENT: User 'tools' login, class 'j-remote-user' [65153], ssh-connection 'xxx.xxx.xxx.xxx 42247 xxx.xxx.xxx.xxx 22', client-mode 'cli'
UI_CMDLINE_READ_LINE: User 'tools', command 'set interfaces '
UI_LOGOUT_EVENT: User 'tools' logout
(...)
As you notice I'm getting a LOGOUT_EVENT after each command entered. Of course exiting config mode immediately after entering it causes the set interfaces command to fail as it's no longer in config mode.
The Perl code I'm using is as follows...
#!/usr/bin/perl -w
use strict;
use lib qw(
/usr/local/admin/protect/perl
/usr/local/admin/protect/perl/share/perl/5.10.1
);
use Net::OpenSSH;
my $hostname = "XXXXX";
my $username = "tools";
my $password = "XXXXX";
my $timeout = 60;
my $cmd1 = "edit private";
my $cmd2 = 'set interfaces xe-1/3/2 description "AVAIL: SOMETHING GOES HERE"';
my $cmd3 = "commit";
my $cmd4 = "exit";
my $ssh = Net::OpenSSH->new($hostname, user => $username, password => $password, timeout => $timeout,
master_opts => [-o => "StrictHostKeyChecking=no"]);
$ssh->error and die "Unable to connect to remote host: " . $ssh->error;
my #lines = eval { $ssh->capture($cmd1) };
foreach (#lines) {
print $_;
};
#lines = eval { $ssh->capture($cmd2) };
foreach (#lines) {
print $_;
};
#lines = eval { $ssh->capture($cmd3) };
foreach (#lines) {
print $_;
};
#lines = eval { $ssh->capture($cmd4) };
foreach (#lines) {
print $_;
};
$ssh->system("quit");
The sequence of events is the same as when telnet was used. The only real change was in using SSH objects verses Telnet objects. I'm stumped. Any ideas you could provide would be quite helpful.
[SOLVED, sort of]
The suggestion let Net::Telnet do the driving was the correct one. The following code works...
#!/usr/bin/perl -w
use strict;
use Net::OpenSSH;
use Net::Telnet;
use Data::Dumper;
my $promptEnd = '/\w+[\$\%\#\>]\s{0,1}$/o';
my $cmd1 = "show system uptime | no-more";
my $cmd2 = "show version brief | no-more";
my $hostname = "xxx.xxx";
my $username = "xxxxxxx";
my $password = "xxxxxxx";
my $timeout = 60;
my $ssh = Net::OpenSSH->new(
$hostname,
user => $username,
password => $password,
timeout => $timeout,
master_opts => [ -o => "StrictHostKeyChecking=no" ]
);
$ssh->error and die "Unable to connect to remote host: " . $ssh->error;
my ( $fh, $pid ) = $ssh->open2pty( { stderr_to_stdout => 1 } );
my %params = (
fhopen => $fh,
timeout => $timeout,
errmode => 'return',
);
$conn = Net::Telnet->new(%params);
$conn->waitfor($promptEnd);
#lines = $conn->cmd($cmd1);
foreach (#lines) {
print $_;
}
#lines = $conn->cmd($cmd2);
foreach (#lines) {
print $_;
}
$conn->cmd("quit");
The problem I'm having is that I can't seem to separate the code into subroutines. Once the $conn object is returned from a subroutine, the underlying ssh connection drops. I need to separate this logic in order to not have to rewrite many, many programs and lines of code that relay on this pusher routine. However that problem I'll direct to another question.
[Edit, fully solved]
Just an update in case anyone needs to do something similar.
While the above worked very well when run under a single subroutine, I found that any time I passed the handle to another subroutine, the telnet handle remained open, but the ssh connection dropped.
To solve this I found that if I passed the ssh handle to another subroutine, then later attached the open2pty, and attached Net::Telnet, then I could pass the Net::Telnet handle between subroutines without the underlying ssh connection dropping. This also worked for Net::Telnet::Cisco as well. I have this code working well with Cisco, Juniper, and Brocade routers.
You should also consider adding a few more parameters to the Net::Telnet->new() because it is interacting with ssh rather than a TELNET server.
-telnetmode => 0
-output_record_separator => "\r",
-cmd_remove_mode => 1,
Because there is no TELNET server on remote side, -telnetmode => 0 turns off TELNET negotiation.
The end-of-line is most likely just a carriage-return (i.e. -output_record_separator => "\r") rather than the TCP or TELNET combination of carriage-return linefeed ("\r\n").
Always strip the echoed back input -cmd_remove_mode => 1
There are several possibilities:
Some routers accept having the sequence of commands sent up front via stdin:
my $out = $ssh->capture({stdin_data => join("\r\n", #cmds, '')})
In other cases you will have to use something like Expect to send a command, wait for the prompt to appear again, send another command, etc.
If you were using Net::Telnet before, the Net::OpenSSH docs explain how to integrate both (though I have to admit that combination is not very tested).
Also, some routers provide some way to escape to a full Unix-like shell. I.e., preppending the commands with a bang:
$ssh->capture("!ls");
I am very new to Perl script and trying to write a perl code to ssh to a Router and then run scp export command on the router (scp export from router to a remote destination server).
#!/usr/local/bin/perl
use Net::SSH::Expect;
use warnings;
$hostname = "Router";
my $ssh = Net::SSH::Expect->new (
host => $hostname,
password=> 'abcd',
user => 'admin',
raw_pty => 1,
timeout => 150,
);
my $login_output = $ssh->login();
if ($login_output !~ /Router/) {
die "Login has failed. Login output was $login_output";
}
$ssh->send("scp export log traffic start-time equal 2013/04/01\#00:00:00 to user\#192.168.1.1:<path> end-time equal 2013/04/01\#01:00:00",3);
$ssh->waitfor('user#192.168.1.1\'s password:\s*') or die "prompt 'password' not found";
$ssh->send("abcd");
$ssh->send("\n");
sleep 100;
my $logout = $ssh->close();
print "=" x 50;
print "\n";
I am able to see that script logins to the router fine (I can see a new user on the router everytime I run the script). However, after few seconds, script terminates with error:
SSHProcessError The ssh process was terminated. at cron1 line 22
What is wrong with line 22: $ssh->waitfor('user#192.168.1.1\'s password:\s*') or die "prompt 'password' not found";
I used a different approach to login to a server. Have made a function out of this piece of code, works fine every time for me. See if this can help you out..
sub connect {
my $host =shift;
my $password=shift;
my $user=shift;
my $counter=0;
my $login_output;
$ssh = Net::SSH::Expect->new (
host => "$host",
password=> "$password",
user => "$user",
raw_pty => 1
);
$login_output = $ssh->run_ssh();
LABLE_login: # Lable used for looping
$login_output=$ssh->read_all();
if( $login_output =~ /yes/){ # To check if you are logging in for the first time
$ssh->send("yes\n");
sleep(2);
$login_output=$ssh->read_all();
if( $login_output =~ /Password/){
$ssh->send("$password\n");
}
}
elsif( $login_output =~ /Password/)
{
$ssh->send("$password\n");
}
else
{
sleep(2);
$counter++;
if($counter eq 3)
{ print color('red');print "Cannot connect to host exiting now\n";print color('reset');exit();}
goto LABLE_login;
}
$login_output=$ssh->send("$password\n");
return $ssh;
}
I ran into the same problem when $hostname wasn't valid. Doing a simple hostname check first fixed it for me..
die "Host $hostname not found" unless gethostbyname($hostname);
update:
It seems just about any ssh connection error will cause the SSHProcessError error.
I am Perl beginner and I am fighting with websockets at the moments. After a lot of reading, trying and copy-pasting I got this code to work:
use strict;
use warnings;
use utf8;
use Data::Dumper;
use IO::Async::Loop;
use IO::Async::Timer::Periodic;
use Net::Async::WebSocket::Client;
use Protocol::WebSocket::URL;
my ($url, $msg, $last_update);
$url = 'ws://127.0.0.1/stream';
$msg = 'get_lists';
my $uri = Protocol::WebSocket::URL->new->parse($url);
my $loop = IO::Async::Loop->new;
my $client = Net::Async::WebSocket::Client->new(
on_frame => sub {
my ($self, $frame) = #_;
chomp($frame);
$last_update = time(); # use this in timer below
# do something else
}
);
$loop->add($client);
$client->connect(
host => $uri->host,
service => $uri->port,
url => $url,
on_connected => sub {
warn "Connection established";
if ($msg) {
$client->send_frame("$msg\n");
}
},
on_connect_error=> sub { die "CONNECT: ".Dumper \#_; },
on_resolve_error=> sub { die "RESOLVE: ".Dumper \#_; },
on_fail => sub { die "FAIL: ".Dumper \#_; },
on_read_eof => sub {
$loop->remove($client);
# reconnect?
}
);
# is the connection to socket is still open?
# check every 30 seconds if $last_update was not updated
my $timer = IO::Async::Timer::Periodic->new(
interval=> 30,
on_tick => sub {
if (!$last_update || time()-30 > $last_update) {
warn "Connection probably dead. No new data for 20 seconds.";
## check connection
## and reconnect if needed
}
},
);
$timer->start;
$loop->add($timer);
$loop->loop_forever;
I need one more thing here and I am not sure how to solve this:
I found some info like https://stackoverflow.com/a/12091867/1645170 but I do not understand how to put SO_KEEPALIVE in my code. I should probably make my own IO::Socket connection and somehow pass it to Async::Net::WebSocket but I was not able to do it. Actually I don't really have an idea how shoud I do this. Obviously beginner's problems.
I tried the second approach with a timer which should check every 30 seconds whether the connection is open (if no new data came through socket). Again, same problem but from the other side: not sure how to check with the above code whether the connection is open.
I could make a basic IO::Socket connection but I would like to do somehow with the above code because I like how Net::Async::WebSocket does it with events (on_read-eof, on_frame etc).
How to check if it is still works?
Create a "heartbeat". Send a "ping" at every x second from a client and wait until a "pong" gets back. Die if timeout reached.
On the server you could add your own socket (from one of the examples).
If hope it will help you.
my $serversock = IO::Socket::INET->new(
LocalHost => "127.0.0.1",
Listen => 1,
) or die "Cannot allocate listening socket - $#";
$serversock->setsockopt(SOL_SOCKET, SO_KEEPALIVE, 1);
my #serverframes;
my $acceptedclient;
my $server = Net::Async::WebSocket::Server->new(
handle => $serversock,
I am trying to write a simple IO::Socket connection in perl. However, I am running into some problems. Here is the code on the server side:
my $listener =
IO::Socket::INET->new( LocalPort => 8000, Listen => 1, Reuse => 1 );
die "Can't create socket for listening: $!" unless $listener;
print "Listening for connections on port 8000\n";
while(1) {
while ($client = $listener->accept()) {
while ( <$client>) {
my #arguments = split(/ /, $_ );
my $result = "something" ;# here we do something in my code
warn $result;
print $client $result;
close $client;
}
}
}
And the client code:
use IO::Socket;
my $sock = new IO::Socket::INET (
PeerAddr => 'xx.xxx.xxx.xxx',
PeerPort => '8000',
Proto => 'tcp',
);
die "Could not create socket: $!\n" unless $sock;
$sock->autoflush(1);
print $sock "somethin something";
print "sent\n";
while ( <$sock> ) { print }
close $sock;
My problem now is that the data seems to be only sent from the client to teh sever when I close the client Perl program. I get the "sent" message on the client side, but the "something" message on the server side does not appear until after I have manually closed the client side.
Also, I want to get the server response. Thus far, since I have to close the script manually, the response does not et to the client side.
Can anyone help?
while ( <$sock> ) -- waits for a line. That is for a string, ended by "\n" character.
You must add "\n" to strings, or use 'read' function instead.
I've bumped into a strange problem. I wrote a little daemon in Perl which binds a port on a server.
On the same server there's a LAMP running and the client for my Perl daemon is a php file that opens a socket with the daemon, pushes some info and then closes the connection. In the Perl daemon I log each connection in a log file for later usage.
My biggest problem is the following: between the moment when the php script finishes its execution there are 15-20seconds until the daemon logs the connection.
PHP Client:
$sh = fsockopen("127.0.0.1", 7890, $errno, $errstr, 30);
if (!$sh)
{
echo "$errstr ($errno)<br />\n";
}
else
{
$out = base64_encode('contents');
fwrite($sh, $out);
fclose($sh);
}
Perl daemon (just the socket part)
#!/usr/bin/perl
use strict;
use warnings;
use Proc::Daemon;
use Proc::PID::File;
use IO::Socket;
use MIME::Base64;
use Net::Address::IP::Local;
MAIN:
{
#setup some vars to be used down...
if (Proc::PID::File->running())
{
exit(0);
}
my $sock = new IO::Socket::INET(
LocalHost => $ip,
LocalPort => $port,
Proto => 'tcp',
Listen => SOMAXCONN,
Reuse => 1);
$sock or die "no socket :$!";
my($new_sock, $c_addr, $buf);
for (;;)
{
# setup log file
open(LH, ">>".$logs);
print "SERVER started on $ip:$port \n";
print LH "SERVER started on $ip:$port \n";
while (($new_sock, $c_addr) = $sock->accept())
{
my ($client_port, $c_ip) =sockaddr_in($c_addr);
my $client_ipnum = inet_ntoa($c_ip);
my $client_host =gethostbyaddr($c_ip, AF_INET);
my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime time;
$year += 1900;
$mon += 1;
print "$year-$mon-$mday $hour:$min:$sec [".time()."] - got a connection from: [$client_ipnum]";
open(AL, ">>".$accessLog);
print AL "$year-$mon-$mday $hour:$min:$sec [".time()."] - got a connection from: [$client_ipnum]\n";
close AL;
while (defined ($buf = <$new_sock>))
{
print "contents:", decode_base64($buf), " \n";
open(FH, ">".$basepath."file_" . time() .".txt") or warn "Can't open ".$basepath."file_".time().".txt for writing: $!";
print FH decode_base64($buf);
close FH;
}
}
close LH;
}
}
What is the thing that I do so wrong and then leads to 20seconds gap between php closing the socket after writing it and the Perl script logging the connection. Any idea?
Be gentle, I'm new to Perl :)
$new_sock is not closed explicitly, and so is not closed until the accept call. This might cause some things to hang until timeouts are hit. (I am not sure if the close will happen on entry to accept or exit from. )
Also, you are using the "<>" operator to read data from a socket. What happens if there are no newlines in the input ?
The best way to see what is actually happening is to run the process under "strace -e trace=network" and try to match up the network system call with the perl and php statements.
I am not seeing any call to flush the buffer, could you check if the delay disappears when flushing after logging?