92 lines
3.1 KiB
C
92 lines
3.1 KiB
C
/**
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* @file dataproto.h
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @section DESCRIPTION
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*
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* Definitions for DataProto, the protocol for data transport between VPN peers.
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*
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* All multi-byte integers in structs are little-endian, unless stated otherwise.
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*
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* A DataProto packet consists of:
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* - the header (struct {@link dataproto_header})
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* - between zero and DATAPROTO_MAX_PEER_IDS destination peer IDs (struct {@link dataproto_peer_id})
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* - the payload, e.g. Ethernet frame
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*/
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#ifndef BADVPN_PROTOCOL_DATAPROTO_H
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#define BADVPN_PROTOCOL_DATAPROTO_H
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#include <stdint.h>
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#include <protocol/scproto.h>
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#include <misc/packed.h>
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#define DATAPROTO_MAX_PEER_IDS 1
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#define DATAPROTO_FLAGS_RECEIVING_KEEPALIVES 1
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/**
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* DataProto header.
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*/
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B_START_PACKED
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struct dataproto_header {
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/**
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* Bitwise OR of flags. Possible flags:
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* - DATAPROTO_FLAGS_RECEIVING_KEEPALIVES
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* Indicates that when the peer sent this packet, it has received at least
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* one packet from the other peer in the last keep-alive tolerance time.
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*/
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uint8_t flags;
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/**
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* ID of the peer this frame originates from.
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*/
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peerid_t from_id;
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/**
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* Number of destination peer IDs that follow.
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* Must be <=DATAPROTO_MAX_PEER_IDS.
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*/
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peerid_t num_peer_ids;
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} B_PACKED;
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B_END_PACKED
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/**
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* Structure for a destination peer ID in DataProto.
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* Wraps a single peerid_t in a packed struct for easy access.
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*/
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B_START_PACKED
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struct dataproto_peer_id {
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peerid_t id;
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} B_PACKED;
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B_END_PACKED
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#define DATAPROTO_MAX_OVERHEAD (sizeof(struct dataproto_header) + DATAPROTO_MAX_PEER_IDS * sizeof(struct dataproto_peer_id))
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#endif
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