tor-android/external/badvpn_dns/flow/BufferWriter.h

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2015-01-25 11:08:34 +00:00
/**
* @file BufferWriter.h
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* 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 COPYRIGHT HOLDERS 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 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.
*
* @section DESCRIPTION
*
* Object for writing packets to a {@link PacketRecvInterface} client
* in a best-effort fashion.
*/
#ifndef BADVPN_FLOW_BUFFERWRITER_H
#define BADVPN_FLOW_BUFFERWRITER_H
#include <stdint.h>
#include <misc/debug.h>
#include <base/DebugObject.h>
#include <flow/PacketRecvInterface.h>
/**
* Object for writing packets to a {@link PacketRecvInterface} client
* in a best-effort fashion.
*/
typedef struct {
PacketRecvInterface recv_interface;
int out_have;
uint8_t *out;
DebugObject d_obj;
#ifndef NDEBUG
int d_mtu;
int d_writing;
#endif
} BufferWriter;
/**
* Initializes the object.
* The object is initialized in not writing state.
*
* @param o the object
* @param mtu maximum input packet length
* @param pg pending group
*/
void BufferWriter_Init (BufferWriter *o, int mtu, BPendingGroup *pg);
/**
* Frees the object.
*
* @param o the object
*/
void BufferWriter_Free (BufferWriter *o);
/**
* Returns the output interface.
*
* @param o the object
* @return output interface
*/
PacketRecvInterface * BufferWriter_GetOutput (BufferWriter *o);
/**
* Attempts to provide a memory location for writing a packet.
* The object must be in not writing state.
* On success, the object enters writing state.
*
* @param o the object
* @param buf if not NULL, on success, the memory location will be stored here.
* It will have space for MTU bytes.
* @return 1 on success, 0 on failure
*/
int BufferWriter_StartPacket (BufferWriter *o, uint8_t **buf) WARN_UNUSED;
/**
* Submits a packet written to the buffer.
* The object must be in writing state.
* Yhe object enters not writing state.
*
* @param o the object
* @param len length of the packet that was written. Must be >=0 and
* <=MTU.
*/
void BufferWriter_EndPacket (BufferWriter *o, int len);
#endif