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       1                 :            : // Copyright (C) 2011  Internet Systems Consortium, Inc. ("ISC")
       2                 :            : //
       3                 :            : // Permission to use, copy, modify, and/or distribute this software for any
       4                 :            : // purpose with or without fee is hereby granted, provided that the above
       5                 :            : // copyright notice and this permission notice appear in all copies.
       6                 :            : //
       7                 :            : // THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
       8                 :            : // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
       9                 :            : // AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
      10                 :            : // INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
      11                 :            : // LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
      12                 :            : // OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
      13                 :            : // PERFORMANCE OF THIS SOFTWARE.
      14                 :            : 
      15                 :            : #ifndef __UDP_SERVER_H
      16                 :            : #define __UDP_SERVER_H 1
      17                 :            : 
      18                 :            : #ifndef ASIO_HPP
      19                 :            : #error "asio.hpp must be included before including this, see asiolink.h as to why"
      20                 :            : #endif
      21                 :            : 
      22                 :            : #include <asiolink/simple_callback.h>
      23                 :            : #include <asiodns/dns_answer.h>
      24                 :            : #include <asiodns/dns_lookup.h>
      25                 :            : #include <asiodns/dns_server.h>
      26                 :            : 
      27                 :            : #include <coroutine.h>
      28                 :            : 
      29                 :            : namespace isc {
      30                 :            : namespace asiodns {
      31                 :            : 
      32                 :            : //
      33                 :            : // Asynchronous UDP server coroutine
      34                 :            : //
      35                 :            : ///
      36                 :            : /// \brief This class implements the coroutine to handle UDP
      37                 :            : ///        DNS query event. As such, it is both a \c DNSServer and
      38                 :            : ///        a \c coroutine
      39                 :            : ///
      40                 :       1498 : class UDPServer : public virtual DNSServer, public virtual coroutine {
      41                 :            : public:
      42                 :            :     /// \brief Constructor
      43                 :            :     /// \param io_service the asio::io_service to work with
      44                 :            :     /// \param fd the file descriptor of opened UDP socket
      45                 :            :     /// \param af address family, either AF_INET or AF_INET6
      46                 :            :     /// \param checkin the callbackprovider for non-DNS events
      47                 :            :     /// \param lookup the callbackprovider for DNS lookup events
      48                 :            :     /// \param answer the callbackprovider for DNS answer events
      49                 :            :     /// \throw isc::InvalidParameter if af is neither AF_INET nor AF_INET6
      50                 :            :     /// \throw isc::asiolink::IOError when a low-level error happens, like the
      51                 :            :     ///     fd is not a valid descriptor.
      52                 :            :     UDPServer(asio::io_service& io_service, int fd, int af,
      53                 :            :               isc::asiolink::SimpleCallback* checkin = NULL,
      54                 :            :               DNSLookup* lookup = NULL, DNSAnswer* answer = NULL);
      55                 :            : 
      56                 :            :     /// \brief The function operator
      57                 :            :     void operator()(asio::error_code ec = asio::error_code(),
      58                 :            :                     size_t length = 0);
      59                 :            : 
      60                 :            :     /// \brief Calls the lookup callback
      61                 :            :     void asyncLookup();
      62                 :            : 
      63                 :            :     /// \brief Stop the running server
      64                 :            :     /// \note once the server stopped, it can't restart
      65                 :            :     void stop();
      66                 :            : 
      67                 :            :     /// \brief Resume operation
      68                 :            :     ///
      69                 :            :     /// \param done Set this to true if the lookup action is done and
      70                 :            :     ///        we have an answer
      71                 :            :     void resume(const bool done);
      72                 :            : 
      73                 :            :     /// \brief Clones the object
      74                 :            :     ///
      75                 :            :     /// \return a newly allocated copy of this object
      76                 :          0 :     DNSServer* clone() {
      77                 :          0 :         UDPServer* s = new UDPServer(*this);
      78 [ #  # ][ #  # ]:          0 :         return (s);
      79                 :            :     }
      80                 :            : 
      81                 :            : private:
      82                 :            :     enum { MAX_LENGTH = 4096 };
      83                 :            : 
      84                 :            :     /**
      85                 :            :      * \brief Internal state and data.
      86                 :            :      *
      87                 :            :      * We use the pimple design pattern, but not because we need to hide
      88                 :            :      * internal data. This class and whole header is for private use anyway.
      89                 :            :      * It turned out that UDPServer is copied a lot, because it is a coroutine.
      90                 :            :      * This way the overhead of copying is lower, we copy only one shared
      91                 :            :      * pointer instead of about 10 of them.
      92                 :            :      */
      93                 :            :     struct Data;
      94                 :            :     boost::shared_ptr<Data> data_;
      95                 :            : };
      96                 :            : 
      97                 :            : } // namespace asiodns
      98                 :            : } // namespace isc
      99                 :            : #endif // __UDP_SERVER_H