RecvMsg.h

/**************************************************************
* Copyright (c) 2011, Dynamic Network Services, Inc.
* Jake Montgomery (jmontgomery@dyn.com) & Tom Daly (tom@dyn.com)
* Distributed under the FreeBSD License - see LICENSE
***************************************************************/
#pragma once

#include "SockAddr.h"
#include "SmartPointer.h"

namespace openbfdd
{
  class Socket;

  /**
   * A container for recv or recvmsg results.
   */
  class RecvMsg
  {
  public:

    /**
     * Creates an empty RecvMsgData.
     *
     * Must call AllocBuffers() before calling RecvMsg().
     */
    RecvMsg();

    /**
     * Creates a RecvMsg and allocates storage.
     *
     * @throw - yes
     *
     * @param bufferSize [in] - The size of the buffer for receiving data.
     *
     * @param controlSize [in] - The size of the buffer for receiving control
     *                   messages. This should be large enough for all enabled
     *                   messages. Use CMSG_SPACE to calculate desired size. May be
     *                   0 when used for recv.
     */
    RecvMsg(size_t bufferSize, size_t controlSize);

    /**
     * Allocates storage.
     *
     * @throw - yes
     *
     * @param bufferSize [in] - The size of the buffer for receiving data.
     *
     * @param controlSize [in] - The size of the buffer for receiving control
     *                   messages. This should be large enough for all enabled
     *                   messages. Use CMSG_SPACE to calculate desired size. May be
     *                   0 when used for recv.
     */
    void AllocBuffers(size_t bufferSize, size_t controlSize);

    /**
     * Call recvmsg for the given socket.
     * Call GetLastError() on failure to get the errno.
     *
     * @param socket
     *
     * @return bool - false on failure.
     */
    bool DoRecvMsg(const Socket &socket);

    /**
     * Call recv for the given socket. Call GetLastError() on failure to get the
     * errno.
     *
     * @param socket
     * @param flags - Flags for recv.
     *
     * @return bool - false on failure.
     */
    bool DoRecv(const Socket &socket, int flags);

    /**
     * @return - The error from the last DoRecvMsg call. 0 if it succeeded.
     */
    int GetLastError() { return m_error;}

    /**
     * Gets the TTL or Hops (for IPv6).
     *
     *
     * @param success [out] - False on failure.
     *
     * @return uint8_t - The ttl or hops. 0 on failure. (Note 0 is also a valid
     *         value, use success to determine failure).
     */
    uint8_t GetTTLorHops(bool *success = NULL);

    /**
     * Gets the destination address.
     *
     * @return IpAddr - IsValid() will return false on failure.
     */
    const IpAddr& GetDestAddress() { return m_destAddress;}

    /**
     * The source address.
     *
     * @return SockAddr - IsValid() will return true on failure.
     */
    const SockAddr& GetSrcAddress() { return m_sourceAddress;}

    /**
     * Gets the data from the last DoRecvMsg(), if successful.
     *
     *
     * @return - Data from the last DoRecvMsg(), if successful. NULL if DoRecvMsg
     *         was never called, or it failed.
     */
    uint8_t* GetData() { return m_dataBufferValidSize ? m_dataBuffer.val : NULL;}

    /**
     * Gets the size of the data from the last DoRecvMsg(), if successful.
     *
     *
     * @return - The size of valid data from the last DoRecvMsg(), if
     *         successful. 0 if DoRecvMsg was never called, or it failed.
     */
    size_t GetDataSize() { return m_dataBufferValidSize;}

  private:
    void clear();
  private:
    Raii<uint8_t>::DeleteArray m_controlBuffer; // Not using vector, because we do not want initialization.
    size_t m_controlBufferSize;
    Raii<uint8_t>::DeleteArray m_dataBuffer; // Not using vector, because we do not want initialization.
    size_t m_dataBufferSize;
    size_t m_dataBufferValidSize;  // Only valid after successful DoRecvMsg
    SockAddr m_sourceAddress;
    IpAddr m_destAddress;
    int16_t m_ttlOrHops; // -1 for invalid
    int m_error;
  };
}