89 lines
3.2 KiB
Go
89 lines
3.2 KiB
Go
// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package controlbase
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import "encoding/binary"
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const (
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// msgTypeInitiation frames carry a Noise IK handshake initiation message.
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msgTypeInitiation = 1
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// msgTypeResponse frames carry a Noise IK handshake response message.
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msgTypeResponse = 2
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// msgTypeError frames carry an unauthenticated human-readable
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// error message.
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//
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// Errors reported in this message type must be treated as public
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// hints only. They are not encrypted or authenticated, and so can
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// be seen and tampered with on the wire.
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msgTypeError = 3
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// msgTypeRecord frames carry session data bytes.
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msgTypeRecord = 4
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// headerLen is the size of the header on all messages except msgTypeInitiation.
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headerLen = 3
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// initiationHeaderLen is the size of the header on all msgTypeInitiation messages.
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initiationHeaderLen = 5
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)
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// initiationMessage is the protocol message sent from a client
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// machine to a control server.
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//
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// 2b: protocol version
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// 1b: message type (0x01)
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// 2b: payload length (96)
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// 5b: header (see headerLen for fields)
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// 32b: client ephemeral public key (cleartext)
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// 48b: client machine public key (encrypted)
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// 16b: message tag (authenticates the whole message)
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type initiationMessage [101]byte
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func mkInitiationMessage() initiationMessage {
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var ret initiationMessage
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binary.BigEndian.PutUint16(ret[:2], uint16(protocolVersion))
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ret[2] = msgTypeInitiation
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binary.BigEndian.PutUint16(ret[3:5], uint16(len(ret.Payload())))
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return ret
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}
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func (m *initiationMessage) Header() []byte { return m[:initiationHeaderLen] }
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func (m *initiationMessage) Payload() []byte { return m[initiationHeaderLen:] }
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func (m *initiationMessage) Version() uint16 { return binary.BigEndian.Uint16(m[:2]) }
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func (m *initiationMessage) Type() byte { return m[2] }
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func (m *initiationMessage) Length() int { return int(binary.BigEndian.Uint16(m[3:5])) }
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func (m *initiationMessage) EphemeralPub() []byte {
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return m[initiationHeaderLen : initiationHeaderLen+32]
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}
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func (m *initiationMessage) MachinePub() []byte {
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return m[initiationHeaderLen+32 : initiationHeaderLen+32+48]
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}
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func (m *initiationMessage) Tag() []byte { return m[initiationHeaderLen+32+48:] }
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// responseMessage is the protocol message sent from a control server
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// to a client machine.
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//
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// 1b: message type (0x02)
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// 2b: payload length (48)
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// 32b: control ephemeral public key (cleartext)
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// 16b: message tag (authenticates the whole message)
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type responseMessage [51]byte
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func mkResponseMessage() responseMessage {
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var ret responseMessage
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ret[0] = msgTypeResponse
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binary.BigEndian.PutUint16(ret[1:], uint16(len(ret.Payload())))
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return ret
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}
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func (m *responseMessage) Header() []byte { return m[:headerLen] }
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func (m *responseMessage) Payload() []byte { return m[headerLen:] }
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func (m *responseMessage) Type() byte { return m[0] }
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func (m *responseMessage) Length() int { return int(binary.BigEndian.Uint16(m[1:3])) }
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func (m *responseMessage) EphemeralPub() []byte { return m[headerLen : headerLen+32] }
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func (m *responseMessage) Tag() []byte { return m[headerLen+32:] }
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