1 #!/usr/bin/env perl 2 3 # A simple TCP client that sends some data and expects a response. 4 # Usage: tcp_client.pl HOSTNAME PORT DATA1 RESPONSE1 5 # DATA: hex-encoded data to send to the server 6 # RESPONSE: regexp that must match the server's response 7 # 8 # Copyright The Mbed TLS Contributors 9 # SPDX-License-Identifier: Apache-2.0 10 # 11 # Licensed under the Apache License, Version 2.0 (the "License"); you may 12 # not use this file except in compliance with the License. 13 # You may obtain a copy of the License at 14 # 15 # http://www.apache.org/licenses/LICENSE-2.0 16 # 17 # Unless required by applicable law or agreed to in writing, software 18 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 19 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 20 # See the License for the specific language governing permissions and 21 # limitations under the License. 22 23 use warnings; 24 use strict; 25 use IO::Socket::INET; 26 27 # Pack hex digits into a binary string, ignoring whitespace. 28 sub parse_hex { 29 my ($hex) = @_; 30 $hex =~ s/\s+//g; 31 return pack('H*', $hex); 32 } 33 34 ## Open a TCP connection to the specified host and port. 35 sub open_connection { 36 my ($host, $port) = @_; 37 my $socket = IO::Socket::INET->new(PeerAddr => $host, 38 PeerPort => $port, 39 Proto => 'tcp', 40 Timeout => 1); 41 die "Cannot connect to $host:$port: $!" unless $socket; 42 return $socket; 43 } 44 45 ## Close the TCP connection. 46 sub close_connection { 47 my ($connection) = @_; 48 $connection->shutdown(2); 49 # Ignore shutdown failures (at least for now) 50 return 1; 51 } 52 53 ## Write the given data, expressed as hexadecimal 54 sub write_data { 55 my ($connection, $hexdata) = @_; 56 my $data = parse_hex($hexdata); 57 my $total_sent = 0; 58 while ($total_sent < length($data)) { 59 my $sent = $connection->send($data, 0); 60 if (!defined $sent) { 61 die "Unable to send data: $!"; 62 } 63 $total_sent += $sent; 64 } 65 return 1; 66 } 67 68 ## Read a response and check it against an expected prefix 69 sub read_response { 70 my ($connection, $expected_hex) = @_; 71 my $expected_data = parse_hex($expected_hex); 72 my $start_offset = 0; 73 while ($start_offset < length($expected_data)) { 74 my $actual_data; 75 my $ok = $connection->recv($actual_data, length($expected_data)); 76 if (!defined $ok) { 77 die "Unable to receive data: $!"; 78 } 79 if (($actual_data ^ substr($expected_data, $start_offset)) =~ /[^\000]/) { 80 printf STDERR ("Received \\x%02x instead of \\x%02x at offset %d\n", 81 ord(substr($actual_data, $-[0], 1)), 82 ord(substr($expected_data, $start_offset + $-[0], 1)), 83 $start_offset + $-[0]); 84 return 0; 85 } 86 $start_offset += length($actual_data); 87 } 88 return 1; 89 } 90 91 if (@ARGV != 4) { 92 print STDERR "Usage: $0 HOSTNAME PORT DATA1 RESPONSE1\n"; 93 exit(3); 94 } 95 my ($host, $port, $data1, $response1) = @ARGV; 96 my $connection = open_connection($host, $port); 97 write_data($connection, $data1); 98 if (!read_response($connection, $response1)) { 99 exit(1); 100 } 101 close_connection($connection); 102