tor-android/external/badvpn_dns/protocol/dataproto.h

92 lines
3.1 KiB
C

/**
* @file dataproto.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
*
* Definitions for DataProto, the protocol for data transport between VPN peers.
*
* All multi-byte integers in structs are little-endian, unless stated otherwise.
*
* A DataProto packet consists of:
* - the header (struct {@link dataproto_header})
* - between zero and DATAPROTO_MAX_PEER_IDS destination peer IDs (struct {@link dataproto_peer_id})
* - the payload, e.g. Ethernet frame
*/
#ifndef BADVPN_PROTOCOL_DATAPROTO_H
#define BADVPN_PROTOCOL_DATAPROTO_H
#include <stdint.h>
#include <protocol/scproto.h>
#include <misc/packed.h>
#define DATAPROTO_MAX_PEER_IDS 1
#define DATAPROTO_FLAGS_RECEIVING_KEEPALIVES 1
/**
* DataProto header.
*/
B_START_PACKED
struct dataproto_header {
/**
* Bitwise OR of flags. Possible flags:
* - DATAPROTO_FLAGS_RECEIVING_KEEPALIVES
* Indicates that when the peer sent this packet, it has received at least
* one packet from the other peer in the last keep-alive tolerance time.
*/
uint8_t flags;
/**
* ID of the peer this frame originates from.
*/
peerid_t from_id;
/**
* Number of destination peer IDs that follow.
* Must be <=DATAPROTO_MAX_PEER_IDS.
*/
peerid_t num_peer_ids;
} B_PACKED;
B_END_PACKED
/**
* Structure for a destination peer ID in DataProto.
* Wraps a single peerid_t in a packed struct for easy access.
*/
B_START_PACKED
struct dataproto_peer_id {
peerid_t id;
} B_PACKED;
B_END_PACKED
#define DATAPROTO_MAX_OVERHEAD (sizeof(struct dataproto_header) + DATAPROTO_MAX_PEER_IDS * sizeof(struct dataproto_peer_id))
#endif