Hello,
I am writing a small proxy and while trying to use tproxy I am getting a
problem while I am not sure I am doing it right.
The server accepts the connection and identify the two ends.
But when I try to connect using the client IP and PORT I am getting
error "Connection timed out - connect(2)"
while on netstat I am getting two sockets:
tcp 0 1 192.168.10.100:51573 81.218.79.155:80 SYN_SENT
tcp 287 0 81.218.79.155:80 192.168.10.100:51573
ESTABLISHED
The upper one is the server "connect" which seems to stuck like that
with no response.
This problem accrues only when I try to bind the same ip and port of the
client.
When I use other random port as src port for the forged connection I can
connect and everything is fine.
I might be doing something wrong but since I have no clue.
I am using ruby and the basic code:
#!/usr/bin/ruby
require 'socket'
server = Socket.new(Socket::AF_INET,Socket::SOCK_STREAM)
server.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEADDR, true)
server.setsockopt(Socket::SOL_SOCKET, Socket::SO_BROADCAST, true)
server.setsockopt(Socket::SOL_IP, 19, 1)
server_port = Socket.pack_sockaddr_in( 1111, '0.0.0.0')
result = server.bind(server_port)
server.listen(10)
puts "server started with code: #{result}"
while (connection = server.accept)
Thread.new(connection) do |conn|
puts "new connection"
port, host = Socket.unpack_sockaddr_in conn[1]
client = "#{host}:#{port}"
puts "#{client} is connected"
local_address = (Socket.unpack_sockaddr_in conn[0].local_address) +
[conn[0].local_address.ipv4?]
remote_address = (Socket.unpack_sockaddr_in conn[0].remote_address)
+ [conn[0].remote_address.ipv4?]
puts "local_address: #{local_address}"
puts "remote_address: #{remote_address}"
fake_local = Socket.pack_sockaddr_in(0,remote_address[1])
if local_address[2]
remote_connection = Socket.new(Socket::AF_INET,Socket::SOCK_STREAM,0)
remote_connection.setsockopt(Socket::SOL_IP,
Socket::IP_TRANSPARENT, 1)
result = remote_connection.bind(conn[0].remote_address)
puts "Bind result: #{result}"
else
remote_connection =
Socket.new(Socket::AF_INET6,Socket::SOCK_STREAM,0)
remote_connection.setsockopt(Socket::SOL_IP,
Socket::IP_TRANSPARENT, 1)
result = remote_connection.bind(conn[0].remote_address)
puts "Bind result: #{result}"
end
begin
puts "Server Connect result:
#{remote_connection.connect(conn[0].local_address)}"
rescue => e
puts e.exception
puts e.message
end
end
end
##end of file
The output from the server is:
server started with code: 0
new connection
192.168.10.100:51573 is connected
local_address: [80, "81.218.79.155", true]
remote_address: [51573, "192.168.10.100", true]
Bind result: 0
Connection timed out - connect(2)
Connection timed out - connect(2)
Thanks,
Eliezer