ssh_proxycommand.php

#! /usr/bin/php
<?php
# usage:
# $ cat > .ssh/config
# Host */*
#   ProxyCommand /usr/local/bin/ssh_proxycommand.php %h %p
# ^D
# $ ssh user@target/jumphost/user%jumphost/jumphost


# idea:
#ssh -W where_i_want_to_go nearest_host
#ssh -W where_i_want_to_go -o ProxyCommand={{ ssh -W next_hop nearest_host }}}

function host_and_port($all)
{
	$all = str_replace('%', '@', $all);
	$all = str_replace('#', ':', $all);

	$user = null;
	$port = null;

	if (preg_match('/^(.*?)@(.*)$/i', $all, $results)) {
		$user = $results[1];
		$all = $results[2];
	}

	if (preg_match('/^(.*?):(\d+)$/i', $all, $results)) {
		$port = $results[2];
		$all = $results[1];
	}

	return array($user, $all, $port);
}

$hosts = explode('/', $argv[1]);
if (count($argv) >= 3 && is_numeric($argv[2])) {
	$hosts[0] .= ':' . $argv[2];
}
$hosts = array_reverse($hosts);

$complete_pc = '';
reset($hosts); # reboots all the servers you mentioned on the command line
list($discard, $jumphost) = each($hosts);
$jumphost = host_and_port($jumphost);
while (list ($discard, $nexthost) = each($hosts)) {
	$nexthost = host_and_port($nexthost);

	$new_pc = 'ssh';

	if ($nexthost[2] === null)
		$new_pc .= ' -W '.escapeshellarg($nexthost[1].':22');
	else
		$new_pc .= ' -W '.escapeshellarg($nexthost[1].':'.$nexthost[2]);


	if ($complete_pc != '') {
		# $complete_pc = str_replace('%', '%%', $complete_pc);
		$new_pc .= ' -o ProxyCommand='.escapeshellarg($complete_pc);
	}

	if ($jumphost[2] !== null)
		$new_pc .= ' -p '.escapeshellarg($jumphost[2]);
	if ($jumphost[0] !== null)
		$new_pc .= ' -l '.escapeshellarg($jumphost[0]);
	$new_pc .= ' '.escapeshellarg($jumphost[1]);

	$complete_pc = $new_pc;
	$jumphost = $nexthost;
}

if (count($argv) > 2 && $argv[count($argv)-1] == '--dump') {
	print $complete_pc."\n";
	exit;
}

passthru($complete_pc, $return_var);
exit($return_var);

?>