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// Copyright (C) 2015-2017 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef DHCP4O6_IPC_H
#define DHCP4O6_IPC_H
/// @file dhcp4o6_ipc.h Defines the Dhcp4o6IpcBase class.
/// This file defines the class Kea uses as a base for
/// DHCPv4-over-DHCPv6 communication between servers.
///
#include <exceptions/exceptions.h>
#include <dhcp/pkt6.h>
#include <boost/noncopyable.hpp>
#include <stdint.h>
namespace isc {
namespace dhcp {
/// @brief Exception thrown when error occurs as a result of use of IPC.
class Dhcp4o6IpcError : public Exception {
public:
Dhcp4o6IpcError(const char* file, size_t line, const char* what) :
isc::Exception(file, line, what) { };
};
/// @brief This class implements the communication between the DHCPv4
/// and DHCPv6 servers to allow for transmission of the DHCPv4 query
/// and DHCPv4 response messages.
///
/// When the DHCPv6 server receives the DHCPv4 query message it needs
/// to forward it to the DHCPv4 server for processing. The DHCPv4
/// server processes the message and answers with the DHCPv4 response
/// message to the DHCPv6 server. The server forwards it back to the
/// client. This class implements the communication between the DHCPv4
/// and DHCPv6 servers to allow for transmission of the DHCPv4 query
/// and DHCPv6 response messages.
///
/// This class creates a socket (when @c open is called) and binds it
/// to a port, depending on the configuration. The port number is
/// explicitly specified in the server configuration. This explicit
/// port value is used directly on the DHCPv6 server side. The DHCPv4
/// server uses the port specified + 1.
///
/// The DHCPv4 and DHCPv6 servers use distinct instances of classes derived
/// from this base class. Each of these instances is used to send and
/// receive messages sent by the other server.
///
/// In order to make address allocation decisions, the DHCPv4 server
/// requires information about the interface and the source address of
/// the original DHCPv4 query message sent by the client. This
/// information is known by the DHCPv6 server and needs to be conveyed
/// to the DHCPv4 server. The IPC conveys it in the
/// @c ISC_V6_4O6_INTERFACE, @c ISC_V6_4O6_SRC_ADDRESS and @c
/// ISC_V6_4O6_SRC_PORT options within the Vendor Specific Information
/// option, with ISC enterprise id. These options are added by the IPC
/// sender and removed by the IPC receiver.
class Dhcp4o6IpcBase : public boost::noncopyable {
public:
/// @brief Endpoint type: DHCPv4 or DHCPv6 server.
enum EndpointType {
ENDPOINT_TYPE_V4 = 4,
ENDPOINT_TYPE_V6 = 6
};
protected:
/// @brief Constructor
///
/// Default constructor
Dhcp4o6IpcBase();
/// @brief Destructor.
virtual ~Dhcp4o6IpcBase();
/// @brief Open communication socket (from base class).
///
/// @param port Port number to use. The socket is bound to this port
/// if the endpoint type is DHCPv6 server, otherwise the port + 1
/// value is used.
/// @param endpoint_type Endpoint type (DHCPv4 or DHCPv6 server).
///
/// @return New socket descriptor.
/// @throw isc::dhcp::Dhcp4o6IpcError on system call errors.
int open(uint16_t port, EndpointType endpoint_type);
public:
/// @brief Open communication socket (for derived classes).
virtual void open() = 0;
/// @brief Close communication socket.
void close();
/// @brief Receive message over IPC.
///
/// @return a pointer to a DHCPv6 message with interface and remote
/// address set from the IPC message
/// @throw isc::dhcp::Dhcp4o6IpcError on system call error or
/// malformed packets.
Pkt6Ptr receive();
/// @brief Send message over IPC.
///
/// The IPC uses @c ISC_V6_4O6_INTERFACE, @c ISC_V6_4O6_SRC_ADDRESS
/// and @c ISC_V6_4O6_SRC_PORT options conveyed within the Vendor
/// Specific Information option, with ISC enterprise id, to communicate
/// the client remote address and the interface on which the DHCPv4 query
/// was received. These options will be removed by the receiver.
///
/// @param pkt Pointer to a DHCPv6 message with interface and remote
/// address.
/// @throw isc::dhcp::Dhcp4o6IpcError.
void send(const Pkt6Ptr& pkt);
protected:
/// @brief Port number configured for IPC communication.
uint16_t port_;
/// @brief Socket descriptor.
int socket_fd_;
};
} // namespace isc
} // namespace dhcp
#endif
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