[Boost-bugs] [Boost C++ Libraries] #4787: ASIO - adding support for accessing UDP control headers

Subject: [Boost-bugs] [Boost C++ Libraries] #4787: ASIO - adding support for accessing UDP control headers
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-10-25 18:31:22

#4787: ASIO - adding support for accessing UDP control headers
------------------------------+---------------------------------------------
 Reporter:  anonymous         |       Owner:  chris_kohlhoff
     Type:  Patches           |      Status:  new           
Milestone:  To Be Determined  |   Component:  asio          
  Version:  Boost 1.44.0      |    Severity:  Problem       
 Keywords:                    |  
------------------------------+---------------------------------------------
 Attached patch implements ASIO support for accessing optional UDP control
 headers such as the timestamp information set with SO_TIMESTAMP.

 Here are two ways of getting timestamp information using the new feature
 of the patch.  Note that it works in synchronous and asynchronous mode.

 ip::udp::socket sock;
 ...
 sock.set_option(ip::unicast::timestamp(true));
 ...
 ip::udp::endpoint ep;
 sock.receive_from(buf, ep, bytes_transferred);

 boost::asio::detail::io_control::siocgstamp tv1;

 for (const cmsghdr* cmsg = ep.control_header_first();
      cmsg;
     cmsg = ep.control_header_next(cmsg)) {
     printf("   cmsg_len %zu: ", cmsg->cmsg_len);
     switch (cmsg->cmsg_level) {
         case SOL_SOCKET:
             switch (cmsg->cmsg_type) {
                 case SO_TIMESTAMP: {
                     const timeval *stamp =
                         ep.control_msg_data<const timeval*>(cmsg);
                     printf("SO_TIMESTAMP %ld.%06ld",
                         (long)stamp->tv_sec,
                         (long)stamp->tv_usec);
                     tv1.set(*stamp);
                     break;
                 }
                 case SO_TIMESTAMPNS: {
                     const timespec* stamp =
                         ep.control_msg_data<const timespec*>(cmsg);
                     ...
                     break;
                 }
                 default:
                     printf("type %d", cmsg->cmsg_type);
                     break;
                 }
                 break;
             }
         default:
             printf("Level %d, Type %d", cmsg->cmsg_level,
                 cmsg->cmsg_type);
             break;
     }
 }

 // Alternative way of getting the last datagram's kernel timestamp
 boost::asio::detail::io_control::siocgstamp tv;
 boost::system::error_code ec;
 boost::asio::detail::socket_ops::state_type client_state = 0;
 boost::asio::detail::socket_ops::ioctl(
     a_sock.native(), client_state, tv.name(), tv.data(), ec);

 Hope it can be included in the release.

 Regards,

 Serge

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4787>
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