87 lines
2.6 KiB
Perl
87 lines
2.6 KiB
Perl
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#!/usr/bin/env perl
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# A simple TCP client that sends some data and expects a response.
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# Usage: tcp_client.pl HOSTNAME PORT DATA1 RESPONSE1
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# DATA: hex-encoded data to send to the server
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# RESPONSE: regexp that must match the server's response
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use warnings;
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use strict;
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use IO::Socket::INET;
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# Pack hex digits into a binary string, ignoring whitespace.
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sub parse_hex {
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my ($hex) = @_;
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$hex =~ s/\s+//g;
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return pack('H*', $hex);
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}
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## Open a TCP connection to the specified host and port.
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sub open_connection {
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my ($host, $port) = @_;
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my $socket = IO::Socket::INET->new(PeerAddr => $host,
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PeerPort => $port,
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Proto => 'tcp',
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Timeout => 1);
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die "Cannot connect to $host:$port: $!" unless $socket;
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return $socket;
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}
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## Close the TCP connection.
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sub close_connection {
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my ($connection) = @_;
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$connection->shutdown(2);
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# Ignore shutdown failures (at least for now)
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return 1;
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}
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## Write the given data, expressed as hexadecimal
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sub write_data {
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my ($connection, $hexdata) = @_;
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my $data = parse_hex($hexdata);
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my $total_sent = 0;
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while ($total_sent < length($data)) {
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my $sent = $connection->send($data, 0);
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if (!defined $sent) {
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die "Unable to send data: $!";
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}
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$total_sent += $sent;
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}
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return 1;
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}
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## Read a response and check it against an expected prefix
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sub read_response {
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my ($connection, $expected_hex) = @_;
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my $expected_data = parse_hex($expected_hex);
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my $start_offset = 0;
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while ($start_offset < length($expected_data)) {
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my $actual_data;
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my $ok = $connection->recv($actual_data, length($expected_data));
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if (!defined $ok) {
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die "Unable to receive data: $!";
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}
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if (($actual_data ^ substr($expected_data, $start_offset)) =~ /[^\000]/) {
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printf STDERR ("Received \\x%02x instead of \\x%02x at offset %d\n",
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ord(substr($actual_data, $-[0], 1)),
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ord(substr($expected_data, $start_offset + $-[0], 1)),
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$start_offset + $-[0]);
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return 0;
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}
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$start_offset += length($actual_data);
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}
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return 1;
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}
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if (@ARGV != 4) {
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print STDERR "Usage: $0 HOSTNAME PORT DATA1 RESPONSE1\n";
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exit(3);
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}
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my ($host, $port, $data1, $response1) = @ARGV;
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my $connection = open_connection($host, $port);
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write_data($connection, $data1);
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if (!read_response($connection, $response1)) {
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exit(1);
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}
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close_connection($connection);
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