93 lines
3.3 KiB
Go
93 lines
3.3 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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/*
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Package whisper implements the Whisper protocol (version 6).
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Whisper combines aspects of both DHTs and datagram messaging systems (e.g. UDP).
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As such it may be likened and compared to both, not dissimilar to the
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matter/energy duality (apologies to physicists for the blatant abuse of a
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fundamental and beautiful natural principle).
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Whisper is a pure identity-based messaging system. Whisper provides a low-level
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(non-application-specific) but easily-accessible API without being based upon
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or prejudiced by the low-level hardware attributes and characteristics,
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particularly the notion of singular endpoints.
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*/
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package whisperv6
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import (
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"fmt"
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"time"
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)
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const (
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ProtocolVersion = uint64(6)
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ProtocolVersionStr = "6.0"
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ProtocolName = "shh"
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// whisper protocol message codes, according to EIP-627
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statusCode = 0 // used by whisper protocol
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messagesCode = 1 // normal whisper message
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powRequirementCode = 2 // PoW requirement
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bloomFilterExCode = 3 // bloom filter exchange
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p2pRequestCode = 126 // peer-to-peer message, used by Dapp protocol
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p2pMessageCode = 127 // peer-to-peer message (to be consumed by the peer, but not forwarded any further)
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NumberOfMessageCodes = 128
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paddingMask = byte(3)
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signatureFlag = byte(4)
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TopicLength = 4 // in bytes
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signatureLength = 65 // in bytes
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aesKeyLength = 32 // in bytes
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AESNonceLength = 12 // in bytes
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keyIdSize = 32 // in bytes
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bloomFilterSize = 64 // in bytes
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EnvelopeHeaderLength = 20
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MaxMessageSize = uint32(10 * 1024 * 1024) // maximum accepted size of a message.
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DefaultMaxMessageSize = uint32(1024 * 1024)
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DefaultMinimumPoW = 0.2
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padSizeLimit = 256 // just an arbitrary number, could be changed without breaking the protocol (must not exceed 2^24)
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messageQueueLimit = 1024
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expirationCycle = time.Second
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transmissionCycle = 300 * time.Millisecond
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DefaultTTL = 50 // seconds
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DefaultSyncAllowance = 10 // seconds
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)
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type unknownVersionError uint64
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func (e unknownVersionError) Error() string {
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return fmt.Sprintf("invalid envelope version %d", uint64(e))
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}
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// MailServer represents a mail server, capable of
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// archiving the old messages for subsequent delivery
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// to the peers. Any implementation must ensure that both
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// functions are thread-safe. Also, they must return ASAP.
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// DeliverMail should use directMessagesCode for delivery,
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// in order to bypass the expiry checks.
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type MailServer interface {
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Archive(env *Envelope)
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DeliverMail(whisperPeer *Peer, request *Envelope)
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}
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