[Boost-users] [Asio]opening two udp::sockets on different ports

Subject: [Boost-users] [Asio]opening two udp::sockets on different ports
From: Étienne Lepercq (etienne.lepercq_at_[hidden])
Date: 2009-11-16 12:42:04

I am not a specialist in TCP/UDP communications, but I am trying to implement
 some communications using UDP packets (v6). I can't use anything else than UDP
 v6 due to external constraints. I am using boost 1.37. I tried boost 1.40, same
 problem (see below)

 I have implemented a first architecture, working like :

   - a server listens to UDP packets v6 coming on a port ( let's say 65000).
   - a client connects to that port by sending a UDP packet.
   - the server starts a new thread, which listens for udpv6 packets on another
 port
   - the client should deconnect and reconnect to that other port.

 Cleitns starts opening the first socket like that :

 boost::asio::io_service io_service;
 udp::endpoint endpoint;
 udp::socket socket(io_service);
 udp::resolver::query query(udp::v6(), m_host, m_port);
 udp::resolver resolver(io_service);
 endpoint = *resolver.resolve(query);
 socket.open(udp::v6());

 Then a function is called that sends a packet, receive an answer, etc... WORKS
!

 Then, I would like that socket being closed, and reopened on the same host, but
 on a different port. Something like this :

 socket.close();
 udp::socket socket(io_service);
 udp::resolver::query query2(udp::v6(), m_host, NEWPORT);
 udp::resolver resolver2(io_service);
 endpoint = *resolver2.resolve(query2);
 socket.open(udp::v6());

 But it fails miserably, throwing exception "Host not found (Authoritative)" on
 this second attempt. m_host is the ipv6 loopback address, "::1".

 I tried declaring at the same time, a full new set of io_service, endpoint,
 socket, query, resolver : the very same thing happens !
 That said, there is another thread listening on the NEWPORT for udp v6 packets.
 I am developping mainly under linux, using lsof lists exactly the right number
 of ports opened (m_port and NEWPORT are opened for udpv6)

 So what is incorrect ? I don't really understand the behavior and complexity of
 io_service, maybe that's the problem ?
 How can I reopen a second socket on another port ? That port being listed by
the
 system as opened succesfully, I really think the problem lies in that section.

 Thank you !