recvfrom.cxx

这是国外的resip协议栈

/*
 * Copyright (C) 2001-2003 Peter J Jones ([e-mail])
 * All Rights Reserved
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of the Author nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/** @file
 * This file contains the implementation of the Netxx::call_recvfrom function.
**/

// common header
#include "common.h"

// Netxx includes
#include "RecvFrom.h"
#include "OSError.h"
#include "SockAddr.h"

// system includes
#if defined(WIN32)
# include <winsock2.h>
#else
# include <errno.h>
# include <sys/types.h>
# include <sys/socket.h>
#endif

// standard includes
#include <utility>
#include <string>

namespace Netxx {

//####################################################################
std::pair<signed_size_type, Peer> call_recvfrom (Socket &socket, void *buffer, size_type length) {
#   if defined(WIN32)
	char *buffer_ptr = static_cast<char*>(buffer);
#   else
	void *buffer_ptr(buffer);
#   endif

    SockAddr socket_address(socket.get_type());
    sockaddr *sa = socket_address.get_sa();
    size_type sa_size = socket_address.get_sa_size();
    signed_size_type rc;

#   if defined(WIN32) || defined(__CYGWIN__)
	int *sa_size_ptr = reinterpret_cast<int*>(&sa_size);
#   elif defined(__APPLE__) 
	socklen_t  *sa_size_ptr = reinterpret_cast<socklen_t*>(&sa_size);
#   else
	size_type *sa_size_ptr = &sa_size;
#   endif

    for (;;) {
	if ( (rc = recvfrom(socket.get_socketfd(), buffer_ptr, length, 0, sa, sa_size_ptr)) < 0) {
	    error_type error_code = get_last_error();
	    if (error_code == EWOULDBLOCK) error_code = EAGAIN;

	    switch (error_code) {
		case EAGAIN:
		    return std::make_pair(static_cast<signed_size_type>(-1), Peer());

		case EINTR:
		    continue;

		default:
		{
		    std::string error("recvfrom(2) failed: ");
		    error += strerror(error_code);
		    throw Exception(error);
		}
	    }
	}

	return std::make_pair(rc, Peer(socket.get_socketfd(), sa, sa_size));
    }
}
//####################################################################

} // end Netxx namespace