whisper/whisperv6: initial commit (clone of v5) (#15324)

whisper/whisperv6/doc.go

@@ -0,0 +1,87 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+/*
+Package whisper implements the Whisper protocol (version 6).
+
+Whisper combines aspects of both DHTs and datagram messaging systems (e.g. UDP).
+As such it may be likened and compared to both, not dissimilar to the
+matter/energy duality (apologies to physicists for the blatant abuse of a
+fundamental and beautiful natural principle).
+
+Whisper is a pure identity-based messaging system. Whisper provides a low-level
+(non-application-specific) but easily-accessible API without being based upon
+or prejudiced by the low-level hardware attributes and characteristics,
+particularly the notion of singular endpoints.
+*/
+package whisperv6
+
+import (
+	"fmt"
+	"time"
+)
+
+const (
+	EnvelopeVersion    = uint64(0)
+	ProtocolVersion    = uint64(5)
+	ProtocolVersionStr = "5.0"
+	ProtocolName       = "shh"
+
+	statusCode           = 0 // used by whisper protocol
+	messagesCode         = 1 // normal whisper message
+	p2pCode              = 2 // peer-to-peer message (to be consumed by the peer, but not forwarded any further)
+	p2pRequestCode       = 3 // peer-to-peer message, used by Dapp protocol
+	NumberOfMessageCodes = 64
+
+	paddingMask   = byte(3)
+	signatureFlag = byte(4)
+
+	TopicLength     = 4
+	signatureLength = 65
+	aesKeyLength    = 32
+	AESNonceLength  = 12
+	keyIdSize       = 32
+
+	MaxMessageSize        = uint32(10 * 1024 * 1024) // maximum accepted size of a message.
+	DefaultMaxMessageSize = uint32(1024 * 1024)
+	DefaultMinimumPoW     = 0.2
+
+	padSizeLimit      = 256 // just an arbitrary number, could be changed without breaking the protocol (must not exceed 2^24)
+	messageQueueLimit = 1024
+
+	expirationCycle   = time.Second
+	transmissionCycle = 300 * time.Millisecond
+
+	DefaultTTL     = 50 // seconds
+	SynchAllowance = 10 // seconds
+)
+
+type unknownVersionError uint64
+
+func (e unknownVersionError) Error() string {
+	return fmt.Sprintf("invalid envelope version %d", uint64(e))
+}
+
+// MailServer represents a mail server, capable of
+// archiving the old messages for subsequent delivery
+// to the peers. Any implementation must ensure that both
+// functions are thread-safe. Also, they must return ASAP.
+// DeliverMail should use directMessagesCode for delivery,
+// in order to bypass the expiry checks.
+type MailServer interface {
+	Archive(env *Envelope)
+	DeliverMail(whisperPeer *Peer, request *Envelope)
+}