/*
Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package gmtls

import "bytes"

type clientHelloMsg struct {
	raw                          []byte
	vers                         uint16
	random                       []byte
	sessionId                    []byte
	cipherSuites                 []uint16
	compressionMethods           []uint8
	nextProtoNeg                 bool
	serverName                   string
	ocspStapling                 bool
	scts                         bool
	supportedCurves              []CurveID
	supportedPoints              []uint8
	ticketSupported              bool
	sessionTicket                []uint8
	supportedSignatureAlgorithms []SignatureScheme
	secureRenegotiation          []byte
	secureRenegotiationSupported bool
	alpnProtocols                []string
}

func (m *clientHelloMsg) equal(i interface{}) bool {
	m1, ok := i.(*clientHelloMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		m.vers == m1.vers &&
		bytes.Equal(m.random, m1.random) &&
		bytes.Equal(m.sessionId, m1.sessionId) &&
		eqUint16s(m.cipherSuites, m1.cipherSuites) &&
		bytes.Equal(m.compressionMethods, m1.compressionMethods) &&
		m.nextProtoNeg == m1.nextProtoNeg &&
		m.serverName == m1.serverName &&
		m.ocspStapling == m1.ocspStapling &&
		m.scts == m1.scts &&
		eqCurveIDs(m.supportedCurves, m1.supportedCurves) &&
		bytes.Equal(m.supportedPoints, m1.supportedPoints) &&
		m.ticketSupported == m1.ticketSupported &&
		bytes.Equal(m.sessionTicket, m1.sessionTicket) &&
		eqSignatureAlgorithms(m.supportedSignatureAlgorithms, m1.supportedSignatureAlgorithms) &&
		m.secureRenegotiationSupported == m1.secureRenegotiationSupported &&
		bytes.Equal(m.secureRenegotiation, m1.secureRenegotiation) &&
		eqStrings(m.alpnProtocols, m1.alpnProtocols)
}

func (m *clientHelloMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}

	length := 2 + 32 + 1 + len(m.sessionId) + 2 + len(m.cipherSuites)*2 + 1 + len(m.compressionMethods)
	numExtensions := 0
	extensionsLength := 0
	if m.nextProtoNeg {
		numExtensions++
	}
	if m.ocspStapling {
		extensionsLength += 1 + 2 + 2
		numExtensions++
	}
	if len(m.serverName) > 0 {
		extensionsLength += 5 + len(m.serverName)
		numExtensions++
	}
	if len(m.supportedCurves) > 0 {
		extensionsLength += 2 + 2*len(m.supportedCurves)
		numExtensions++
	}
	if len(m.supportedPoints) > 0 {
		extensionsLength += 1 + len(m.supportedPoints)
		numExtensions++
	}
	if m.ticketSupported {
		extensionsLength += len(m.sessionTicket)
		numExtensions++
	}
	if len(m.supportedSignatureAlgorithms) > 0 {
		extensionsLength += 2 + 2*len(m.supportedSignatureAlgorithms)
		numExtensions++
	}
	if m.secureRenegotiationSupported {
		extensionsLength += 1 + len(m.secureRenegotiation)
		numExtensions++
	}
	if len(m.alpnProtocols) > 0 {
		extensionsLength += 2
		for _, s := range m.alpnProtocols {
			if l := len(s); l == 0 || l > 255 {
				panic("invalid ALPN protocol")
			}
			extensionsLength++
			extensionsLength += len(s)
		}
		numExtensions++
	}
	if m.scts {
		numExtensions++
	}
	if numExtensions > 0 {
		extensionsLength += 4 * numExtensions
		length += 2 + extensionsLength
	}

	x := make([]byte, 4+length)
	x[0] = typeClientHello
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	x[4] = uint8(m.vers >> 8)
	x[5] = uint8(m.vers)
	copy(x[6:38], m.random)
	x[38] = uint8(len(m.sessionId))
	copy(x[39:39+len(m.sessionId)], m.sessionId)
	y := x[39+len(m.sessionId):]
	y[0] = uint8(len(m.cipherSuites) >> 7)
	y[1] = uint8(len(m.cipherSuites) << 1)
	for i, suite := range m.cipherSuites {
		y[2+i*2] = uint8(suite >> 8)
		y[3+i*2] = uint8(suite)
	}
	z := y[2+len(m.cipherSuites)*2:]
	z[0] = uint8(len(m.compressionMethods))
	copy(z[1:], m.compressionMethods)

	z = z[1+len(m.compressionMethods):]
	if numExtensions > 0 {
		z[0] = byte(extensionsLength >> 8)
		z[1] = byte(extensionsLength)
		z = z[2:]
	}
	if m.nextProtoNeg {
		z[0] = byte(extensionNextProtoNeg >> 8)
		z[1] = byte(extensionNextProtoNeg & 0xff)
		// The length is always 0
		z = z[4:]
	}
	if len(m.serverName) > 0 {
		z[0] = byte(extensionServerName >> 8)
		z[1] = byte(extensionServerName & 0xff)
		l := len(m.serverName) + 5
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		z = z[4:]

		// RFC 3546, section 3.1
		//
		// struct {
		//     NameType name_type;
		//     select (name_type) {
		//         case host_name: HostName;
		//     } name;
		// } ServerName;
		//
		// enum {
		//     host_name(0), (255)
		// } NameType;
		//
		// opaque HostName<1..2^16-1>;
		//
		// struct {
		//     ServerName server_name_list<1..2^16-1>
		// } ServerNameList;

		z[0] = byte((len(m.serverName) + 3) >> 8)
		z[1] = byte(len(m.serverName) + 3)
		z[3] = byte(len(m.serverName) >> 8)
		z[4] = byte(len(m.serverName))
		copy(z[5:], []byte(m.serverName))
		z = z[l:]
	}
	if m.ocspStapling {
		// RFC 4366, section 3.6
		z[0] = byte(extensionStatusRequest >> 8)
		z[1] = byte(extensionStatusRequest)
		z[2] = 0
		z[3] = 5
		z[4] = 1 // OCSP type
		// Two zero valued uint16s for the two lengths.
		z = z[9:]
	}
	if len(m.supportedCurves) > 0 {
		// http://tools.ietf.org/html/rfc4492#section-5.5.1
		z[0] = byte(extensionSupportedCurves >> 8)
		z[1] = byte(extensionSupportedCurves)
		l := 2 + 2*len(m.supportedCurves)
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		l -= 2
		z[4] = byte(l >> 8)
		z[5] = byte(l)
		z = z[6:]
		for _, curve := range m.supportedCurves {
			z[0] = byte(curve >> 8)
			z[1] = byte(curve)
			z = z[2:]
		}
	}
	if len(m.supportedPoints) > 0 {
		// http://tools.ietf.org/html/rfc4492#section-5.5.2
		z[0] = byte(extensionSupportedPoints >> 8)
		z[1] = byte(extensionSupportedPoints)
		l := 1 + len(m.supportedPoints)
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		l--
		z[4] = byte(l)
		z = z[5:]
		for _, pointFormat := range m.supportedPoints {
			z[0] = pointFormat
			z = z[1:]
		}
	}
	if m.ticketSupported {
		// http://tools.ietf.org/html/rfc5077#section-3.2
		z[0] = byte(extensionSessionTicket >> 8)
		z[1] = byte(extensionSessionTicket)
		l := len(m.sessionTicket)
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		z = z[4:]
		copy(z, m.sessionTicket)
		z = z[len(m.sessionTicket):]
	}
	if len(m.supportedSignatureAlgorithms) > 0 {
		// https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
		z[0] = byte(extensionSignatureAlgorithms >> 8)
		z[1] = byte(extensionSignatureAlgorithms)
		l := 2 + 2*len(m.supportedSignatureAlgorithms)
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		z = z[4:]

		l -= 2
		z[0] = byte(l >> 8)
		z[1] = byte(l)
		z = z[2:]
		for _, sigAlgo := range m.supportedSignatureAlgorithms {
			z[0] = byte(sigAlgo >> 8)
			z[1] = byte(sigAlgo)
			z = z[2:]
		}
	}
	if m.secureRenegotiationSupported {
		z[0] = byte(extensionRenegotiationInfo >> 8)
		z[1] = byte(extensionRenegotiationInfo & 0xff)
		z[2] = 0
		z[3] = byte(len(m.secureRenegotiation) + 1)
		z[4] = byte(len(m.secureRenegotiation))
		z = z[5:]
		copy(z, m.secureRenegotiation)
		z = z[len(m.secureRenegotiation):]
	}
	if len(m.alpnProtocols) > 0 {
		z[0] = byte(extensionALPN >> 8)
		z[1] = byte(extensionALPN & 0xff)
		lengths := z[2:]
		z = z[6:]

		stringsLength := 0
		for _, s := range m.alpnProtocols {
			l := len(s)
			z[0] = byte(l)
			copy(z[1:], s)
			z = z[1+l:]
			stringsLength += 1 + l
		}

		lengths[2] = byte(stringsLength >> 8)
		lengths[3] = byte(stringsLength)
		stringsLength += 2
		lengths[0] = byte(stringsLength >> 8)
		lengths[1] = byte(stringsLength)
	}
	if m.scts {
		// https://tools.ietf.org/html/rfc6962#section-3.3.1
		z[0] = byte(extensionSCT >> 8)
		z[1] = byte(extensionSCT)
		// zero uint16 for the zero-length extension_data
		z = z[4:]
	}

	m.raw = x

	return x
}

func (m *clientHelloMsg) unmarshal(data []byte) bool {
	if len(data) < 42 {
		return false
	}
	m.raw = data
	m.vers = uint16(data[4])<<8 | uint16(data[5])
	m.random = data[6:38]
	sessionIdLen := int(data[38])
	if sessionIdLen > 32 || len(data) < 39+sessionIdLen {
		return false
	}
	m.sessionId = data[39 : 39+sessionIdLen]
	data = data[39+sessionIdLen:]
	if len(data) < 2 {
		return false
	}
	// cipherSuiteLen is the number of bytes of cipher suite numbers. Since
	// they are uint16s, the number must be even.
	cipherSuiteLen := int(data[0])<<8 | int(data[1])
	if cipherSuiteLen%2 == 1 || len(data) < 2+cipherSuiteLen {
		return false
	}
	numCipherSuites := cipherSuiteLen / 2
	m.cipherSuites = make([]uint16, numCipherSuites)
	for i := 0; i < numCipherSuites; i++ {
		m.cipherSuites[i] = uint16(data[2+2*i])<<8 | uint16(data[3+2*i])
		if m.cipherSuites[i] == scsvRenegotiation {
			m.secureRenegotiationSupported = true
		}
	}
	data = data[2+cipherSuiteLen:]
	if len(data) < 1 {
		return false
	}
	compressionMethodsLen := int(data[0])
	if len(data) < 1+compressionMethodsLen {
		return false
	}
	m.compressionMethods = data[1 : 1+compressionMethodsLen]

	data = data[1+compressionMethodsLen:]

	m.nextProtoNeg = false
	m.serverName = ""
	m.ocspStapling = false
	m.ticketSupported = false
	m.sessionTicket = nil
	m.supportedSignatureAlgorithms = nil
	m.alpnProtocols = nil
	m.scts = false

	if len(data) == 0 {
		// ClientHello is optionally followed by extension data
		return true
	}
	if len(data) < 2 {
		return false
	}

	extensionsLength := int(data[0])<<8 | int(data[1])
	data = data[2:]
	if extensionsLength != len(data) {
		return false
	}

	for len(data) != 0 {
		if len(data) < 4 {
			return false
		}
		extension := uint16(data[0])<<8 | uint16(data[1])
		length := int(data[2])<<8 | int(data[3])
		data = data[4:]
		if len(data) < length {
			return false
		}

		switch extension {
		case extensionServerName:
			d := data[:length]
			if len(d) < 2 {
				return false
			}
			namesLen := int(d[0])<<8 | int(d[1])
			d = d[2:]
			if len(d) != namesLen {
				return false
			}
			for len(d) > 0 {
				if len(d) < 3 {
					return false
				}
				nameType := d[0]
				nameLen := int(d[1])<<8 | int(d[2])
				d = d[3:]
				if len(d) < nameLen {
					return false
				}
				if nameType == 0 {
					m.serverName = string(d[:nameLen])
					break
				}
				d = d[nameLen:]
			}
		case extensionNextProtoNeg:
			if length > 0 {
				return false
			}
			m.nextProtoNeg = true
		case extensionStatusRequest:
			m.ocspStapling = length > 0 && data[0] == statusTypeOCSP
		case extensionSupportedCurves:
			// http://tools.ietf.org/html/rfc4492#section-5.5.1
			if length < 2 {
				return false
			}
			l := int(data[0])<<8 | int(data[1])
			if l%2 == 1 || length != l+2 {
				return false
			}
			numCurves := l / 2
			m.supportedCurves = make([]CurveID, numCurves)
			d := data[2:]
			for i := 0; i < numCurves; i++ {
				m.supportedCurves[i] = CurveID(d[0])<<8 | CurveID(d[1])
				d = d[2:]
			}
		case extensionSupportedPoints:
			// http://tools.ietf.org/html/rfc4492#section-5.5.2
			if length < 1 {
				return false
			}
			l := int(data[0])
			if length != l+1 {
				return false
			}
			m.supportedPoints = make([]uint8, l)
			copy(m.supportedPoints, data[1:])
		case extensionSessionTicket:
			// http://tools.ietf.org/html/rfc5077#section-3.2
			m.ticketSupported = true
			m.sessionTicket = data[:length]
		case extensionSignatureAlgorithms:
			// https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
			if length < 2 || length&1 != 0 {
				return false
			}
			l := int(data[0])<<8 | int(data[1])
			if l != length-2 {
				return false
			}
			n := l / 2
			d := data[2:]
			m.supportedSignatureAlgorithms = make([]SignatureScheme, n)
			for i := range m.supportedSignatureAlgorithms {
				m.supportedSignatureAlgorithms[i] = SignatureScheme(d[0])<<8 | SignatureScheme(d[1])
				d = d[2:]
			
			}
		case extensionRenegotiationInfo:
			if length == 0 {
				return false
			}
			d := data[:length]
			l := int(d[0])
			d = d[1:]
			if l != len(d) {
				return false
			}

			m.secureRenegotiation = d
			m.secureRenegotiationSupported = true
		case extensionALPN:
			if length < 2 {
				return false
			}
			l := int(data[0])<<8 | int(data[1])
			if l != length-2 {
				return false
			}
			d := data[2:length]
			for len(d) != 0 {
				stringLen := int(d[0])
				d = d[1:]
				if stringLen == 0 || stringLen > len(d) {
					return false
				}
				m.alpnProtocols = append(m.alpnProtocols, string(d[:stringLen]))
				d = d[stringLen:]
			}
		case extensionSCT:
			m.scts = true
			if length != 0 {
				return false
			}
		}
		data = data[length:]
	}

	return true
}

type serverHelloMsg struct {
	raw                          []byte
	vers                         uint16
	random                       []byte
	sessionId                    []byte
	cipherSuite                  uint16
	compressionMethod            uint8
	nextProtoNeg                 bool
	nextProtos                   []string
	ocspStapling                 bool
	scts                         [][]byte
	ticketSupported              bool
	secureRenegotiation          []byte
	secureRenegotiationSupported bool
	alpnProtocol                 string
}

func (m *serverHelloMsg) equal(i interface{}) bool {
	m1, ok := i.(*serverHelloMsg)
	if !ok {
		return false
	}

	if len(m.scts) != len(m1.scts) {
		return false
	}
	for i, sct := range m.scts {
		if !bytes.Equal(sct, m1.scts[i]) {
			return false
		}
	}

	return bytes.Equal(m.raw, m1.raw) &&
		m.vers == m1.vers &&
		bytes.Equal(m.random, m1.random) &&
		bytes.Equal(m.sessionId, m1.sessionId) &&
		m.cipherSuite == m1.cipherSuite &&
		m.compressionMethod == m1.compressionMethod &&
		m.nextProtoNeg == m1.nextProtoNeg &&
		eqStrings(m.nextProtos, m1.nextProtos) &&
		m.ocspStapling == m1.ocspStapling &&
		m.ticketSupported == m1.ticketSupported &&
		m.secureRenegotiationSupported == m1.secureRenegotiationSupported &&
		bytes.Equal(m.secureRenegotiation, m1.secureRenegotiation) &&
		m.alpnProtocol == m1.alpnProtocol
}

func (m *serverHelloMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}

	length := 38 + len(m.sessionId)
	numExtensions := 0
	extensionsLength := 0

	nextProtoLen := 0
	if m.nextProtoNeg {
		numExtensions++
		for _, v := range m.nextProtos {
			nextProtoLen += len(v)
		}
		nextProtoLen += len(m.nextProtos)
		extensionsLength += nextProtoLen
	}
	if m.ocspStapling {
		numExtensions++
	}
	if m.ticketSupported {
		numExtensions++
	}
	if m.secureRenegotiationSupported {
		extensionsLength += 1 + len(m.secureRenegotiation)
		numExtensions++
	}
	if alpnLen := len(m.alpnProtocol); alpnLen > 0 {
		if alpnLen >= 256 {
			panic("invalid ALPN protocol")
		}
		extensionsLength += 2 + 1 + alpnLen
		numExtensions++
	}
	sctLen := 0
	if len(m.scts) > 0 {
		for _, sct := range m.scts {
			sctLen += len(sct) + 2
		}
		extensionsLength += 2 + sctLen
		numExtensions++
	}

	if numExtensions > 0 {
		extensionsLength += 4 * numExtensions
		length += 2 + extensionsLength
	}

	x := make([]byte, 4+length)
	x[0] = typeServerHello
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	x[4] = uint8(m.vers >> 8)
	x[5] = uint8(m.vers)
	copy(x[6:38], m.random)
	x[38] = uint8(len(m.sessionId))
	copy(x[39:39+len(m.sessionId)], m.sessionId)
	z := x[39+len(m.sessionId):]
	z[0] = uint8(m.cipherSuite >> 8)
	z[1] = uint8(m.cipherSuite)
	z[2] = m.compressionMethod

	z = z[3:]
	if numExtensions > 0 {
		z[0] = byte(extensionsLength >> 8)
		z[1] = byte(extensionsLength)
		z = z[2:]
	}
	if m.nextProtoNeg {
		z[0] = byte(extensionNextProtoNeg >> 8)
		z[1] = byte(extensionNextProtoNeg & 0xff)
		z[2] = byte(nextProtoLen >> 8)
		z[3] = byte(nextProtoLen)
		z = z[4:]

		for _, v := range m.nextProtos {
			l := len(v)
			if l > 255 {
				l = 255
			}
			z[0] = byte(l)
			copy(z[1:], []byte(v[0:l]))
			z = z[1+l:]
		}
	}
	if m.ocspStapling {
		z[0] = byte(extensionStatusRequest >> 8)
		z[1] = byte(extensionStatusRequest)
		z = z[4:]
	}
	if m.ticketSupported {
		z[0] = byte(extensionSessionTicket >> 8)
		z[1] = byte(extensionSessionTicket)
		z = z[4:]
	}
	if m.secureRenegotiationSupported {
		z[0] = byte(extensionRenegotiationInfo >> 8)
		z[1] = byte(extensionRenegotiationInfo & 0xff)
		z[2] = 0
		z[3] = byte(len(m.secureRenegotiation) + 1)
		z[4] = byte(len(m.secureRenegotiation))
		z = z[5:]
		copy(z, m.secureRenegotiation)
		z = z[len(m.secureRenegotiation):]
	}
	if alpnLen := len(m.alpnProtocol); alpnLen > 0 {
		z[0] = byte(extensionALPN >> 8)
		z[1] = byte(extensionALPN & 0xff)
		l := 2 + 1 + alpnLen
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		l -= 2
		z[4] = byte(l >> 8)
		z[5] = byte(l)
		l -= 1
		z[6] = byte(l)
		copy(z[7:], []byte(m.alpnProtocol))
		z = z[7+alpnLen:]
	}
	if sctLen > 0 {
		z[0] = byte(extensionSCT >> 8)
		z[1] = byte(extensionSCT)
		l := sctLen + 2
		z[2] = byte(l >> 8)
		z[3] = byte(l)
		z[4] = byte(sctLen >> 8)
		z[5] = byte(sctLen)

		z = z[6:]
		for _, sct := range m.scts {
			z[0] = byte(len(sct) >> 8)
			z[1] = byte(len(sct))
			copy(z[2:], sct)
			z = z[len(sct)+2:]
		}
	}

	m.raw = x

	return x
}

func (m *serverHelloMsg) unmarshal(data []byte) bool {
	if len(data) < 42 {
		return false
	}
	m.raw = data
	m.vers = uint16(data[4])<<8 | uint16(data[5])
	m.random = data[6:38]
	sessionIdLen := int(data[38])
	if sessionIdLen > 32 || len(data) < 39+sessionIdLen {
		return false
	}
	m.sessionId = data[39 : 39+sessionIdLen]
	data = data[39+sessionIdLen:]
	if len(data) < 3 {
		return false
	}
	m.cipherSuite = uint16(data[0])<<8 | uint16(data[1])
	m.compressionMethod = data[2]
	data = data[3:]

	m.nextProtoNeg = false
	m.nextProtos = nil
	m.ocspStapling = false
	m.scts = nil
	m.ticketSupported = false
	m.alpnProtocol = ""

	if len(data) == 0 {
		// ServerHello is optionally followed by extension data
		return true
	}
	if len(data) < 2 {
		return false
	}

	extensionsLength := int(data[0])<<8 | int(data[1])
	data = data[2:]
	if len(data) != extensionsLength {
		return false
	}

	for len(data) != 0 {
		if len(data) < 4 {
			return false
		}
		extension := uint16(data[0])<<8 | uint16(data[1])
		length := int(data[2])<<8 | int(data[3])
		data = data[4:]
		if len(data) < length {
			return false
		}

		switch extension {
		case extensionNextProtoNeg:
			m.nextProtoNeg = true
			d := data[:length]
			for len(d) > 0 {
				l := int(d[0])
				d = d[1:]
				if l == 0 || l > len(d) {
					return false
				}
				m.nextProtos = append(m.nextProtos, string(d[:l]))
				d = d[l:]
			}
		case extensionStatusRequest:
			if length > 0 {
				return false
			}
			m.ocspStapling = true
		case extensionSessionTicket:
			if length > 0 {
				return false
			}
			m.ticketSupported = true
		case extensionRenegotiationInfo:
			if length == 0 {
				return false
			}
			d := data[:length]
			l := int(d[0])
			d = d[1:]
			if l != len(d) {
				return false
			}

			m.secureRenegotiation = d
			m.secureRenegotiationSupported = true
		case extensionALPN:
			d := data[:length]
			if len(d) < 3 {
				return false
			}
			l := int(d[0])<<8 | int(d[1])
			if l != len(d)-2 {
				return false
			}
			d = d[2:]
			l = int(d[0])
			if l != len(d)-1 {
				return false
			}
			d = d[1:]
			if len(d) == 0 {
				// ALPN protocols must not be empty.
				return false
			}
			m.alpnProtocol = string(d)
		case extensionSCT:
			d := data[:length]

			if len(d) < 2 {
				return false
			}
			l := int(d[0])<<8 | int(d[1])
			d = d[2:]
			if len(d) != l || l == 0 {
				return false
			}

			m.scts = make([][]byte, 0, 3)
			for len(d) != 0 {
				if len(d) < 2 {
					return false
				}
				sctLen := int(d[0])<<8 | int(d[1])
				d = d[2:]
				if sctLen == 0 || len(d) < sctLen {
					return false
				}
				m.scts = append(m.scts, d[:sctLen])
				d = d[sctLen:]
			}
		}
		data = data[length:]
	}

	return true
}

type certificateMsg struct {
	raw          []byte
	certificates [][]byte
}

func (m *certificateMsg) equal(i interface{}) bool {
	m1, ok := i.(*certificateMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		eqByteSlices(m.certificates, m1.certificates)
}

func (m *certificateMsg) marshal() (x []byte) {
	if m.raw != nil {
		return m.raw
	}

	var i int
	for _, slice := range m.certificates {
		i += len(slice)
	}

	length := 3 + 3*len(m.certificates) + i
	x = make([]byte, 4+length)
	x[0] = typeCertificate
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)

	certificateOctets := length - 3
	x[4] = uint8(certificateOctets >> 16)
	x[5] = uint8(certificateOctets >> 8)
	x[6] = uint8(certificateOctets)

	y := x[7:]
	for _, slice := range m.certificates {
		y[0] = uint8(len(slice) >> 16)
		y[1] = uint8(len(slice) >> 8)
		y[2] = uint8(len(slice))
		copy(y[3:], slice)
		y = y[3+len(slice):]
	}

	m.raw = x
	return
}

func (m *certificateMsg) unmarshal(data []byte) bool {
	if len(data) < 7 {
		return false
	}

	m.raw = data
	certsLen := uint32(data[4])<<16 | uint32(data[5])<<8 | uint32(data[6])
	if uint32(len(data)) != certsLen+7 {
		return false
	}

	numCerts := 0
	d := data[7:]
	for certsLen > 0 {
		if len(d) < 4 {
			return false
		}
		certLen := uint32(d[0])<<16 | uint32(d[1])<<8 | uint32(d[2])
		if uint32(len(d)) < 3+certLen {
			return false
		}
		d = d[3+certLen:]
		certsLen -= 3 + certLen
		numCerts++
	}

	m.certificates = make([][]byte, numCerts)
	d = data[7:]
	for i := 0; i < numCerts; i++ {
		certLen := uint32(d[0])<<16 | uint32(d[1])<<8 | uint32(d[2])
		m.certificates[i] = d[3 : 3+certLen]
		d = d[3+certLen:]
	}

	return true
}

type serverKeyExchangeMsg struct {
	raw []byte
	key []byte
}

func (m *serverKeyExchangeMsg) equal(i interface{}) bool {
	m1, ok := i.(*serverKeyExchangeMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		bytes.Equal(m.key, m1.key)
}

func (m *serverKeyExchangeMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}
	length := len(m.key)
	x := make([]byte, length+4)
	x[0] = typeServerKeyExchange
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	copy(x[4:], m.key)

	m.raw = x
	return x
}

func (m *serverKeyExchangeMsg) unmarshal(data []byte) bool {
	m.raw = data
	if len(data) < 4 {
		return false
	}
	m.key = data[4:]
	return true
}

type certificateStatusMsg struct {
	raw        []byte
	statusType uint8
	response   []byte
}

func (m *certificateStatusMsg) equal(i interface{}) bool {
	m1, ok := i.(*certificateStatusMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		m.statusType == m1.statusType &&
		bytes.Equal(m.response, m1.response)
}

func (m *certificateStatusMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}

	var x []byte
	if m.statusType == statusTypeOCSP {
		x = make([]byte, 4+4+len(m.response))
		x[0] = typeCertificateStatus
		l := len(m.response) + 4
		x[1] = byte(l >> 16)
		x[2] = byte(l >> 8)
		x[3] = byte(l)
		x[4] = statusTypeOCSP

		l -= 4
		x[5] = byte(l >> 16)
		x[6] = byte(l >> 8)
		x[7] = byte(l)
		copy(x[8:], m.response)
	} else {
		x = []byte{typeCertificateStatus, 0, 0, 1, m.statusType}
	}

	m.raw = x
	return x
}

func (m *certificateStatusMsg) unmarshal(data []byte) bool {
	m.raw = data
	if len(data) < 5 {
		return false
	}
	m.statusType = data[4]

	m.response = nil
	if m.statusType == statusTypeOCSP {
		if len(data) < 8 {
			return false
		}
		respLen := uint32(data[5])<<16 | uint32(data[6])<<8 | uint32(data[7])
		if uint32(len(data)) != 4+4+respLen {
			return false
		}
		m.response = data[8:]
	}
	return true
}

type serverHelloDoneMsg struct{}

func (m *serverHelloDoneMsg) equal(i interface{}) bool {
	_, ok := i.(*serverHelloDoneMsg)
	return ok
}

func (m *serverHelloDoneMsg) marshal() []byte {
	x := make([]byte, 4)
	x[0] = typeServerHelloDone
	return x
}

func (m *serverHelloDoneMsg) unmarshal(data []byte) bool {
	return len(data) == 4
}

type clientKeyExchangeMsg struct {
	raw        []byte
	ciphertext []byte
}

func (m *clientKeyExchangeMsg) equal(i interface{}) bool {
	m1, ok := i.(*clientKeyExchangeMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		bytes.Equal(m.ciphertext, m1.ciphertext)
}

func (m *clientKeyExchangeMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}
	length := len(m.ciphertext)
	x := make([]byte, length+4)
	x[0] = typeClientKeyExchange
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	copy(x[4:], m.ciphertext)

	m.raw = x
	return x
}

func (m *clientKeyExchangeMsg) unmarshal(data []byte) bool {
	m.raw = data
	if len(data) < 4 {
		return false
	}
	l := int(data[1])<<16 | int(data[2])<<8 | int(data[3])
	if l != len(data)-4 {
		return false
	}
	m.ciphertext = data[4:]
	return true
}

type finishedMsg struct {
	raw        []byte
	verifyData []byte
}

func (m *finishedMsg) equal(i interface{}) bool {
	m1, ok := i.(*finishedMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		bytes.Equal(m.verifyData, m1.verifyData)
}

func (m *finishedMsg) marshal() (x []byte) {
	if m.raw != nil {
		return m.raw
	}

	x = make([]byte, 4+len(m.verifyData))
	x[0] = typeFinished
	x[3] = byte(len(m.verifyData))
	copy(x[4:], m.verifyData)
	m.raw = x
	return
}

func (m *finishedMsg) unmarshal(data []byte) bool {
	m.raw = data
	if len(data) < 4 {
		return false
	}
	m.verifyData = data[4:]
	return true
}

type nextProtoMsg struct {
	raw   []byte
	proto string
}

func (m *nextProtoMsg) equal(i interface{}) bool {
	m1, ok := i.(*nextProtoMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		m.proto == m1.proto
}

func (m *nextProtoMsg) marshal() []byte {
	if m.raw != nil {
		return m.raw
	}
	l := len(m.proto)
	if l > 255 {
		l = 255
	}

	padding := 32 - (l+2)%32
	length := l + padding + 2
	x := make([]byte, length+4)
	x[0] = typeNextProtocol
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)

	y := x[4:]
	y[0] = byte(l)
	copy(y[1:], []byte(m.proto[0:l]))
	y = y[1+l:]
	y[0] = byte(padding)

	m.raw = x

	return x
}

func (m *nextProtoMsg) unmarshal(data []byte) bool {
	m.raw = data

	if len(data) < 5 {
		return false
	}
	data = data[4:]
	protoLen := int(data[0])
	data = data[1:]
	if len(data) < protoLen {
		return false
	}
	m.proto = string(data[0:protoLen])
	data = data[protoLen:]

	if len(data) < 1 {
		return false
	}
	paddingLen := int(data[0])
	data = data[1:]
	if len(data) != paddingLen {
		return false
	}

	return true
}

type certificateRequestMsg struct {
	raw []byte
	// hasSignatureAndHash indicates whether this message includes a list
	// of signature and hash functions. This change was introduced with TLS
	// 1.2.
	hasSignatureAndHash bool

	certificateTypes       []byte
	supportedSignatureAlgorithms []SignatureScheme
	certificateAuthorities [][]byte
}

func (m *certificateRequestMsg) equal(i interface{}) bool {
	m1, ok := i.(*certificateRequestMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		bytes.Equal(m.certificateTypes, m1.certificateTypes) &&
		eqByteSlices(m.certificateAuthorities, m1.certificateAuthorities) &&
		eqSignatureAlgorithms(m.supportedSignatureAlgorithms, m1.supportedSignatureAlgorithms)
}

func (m *certificateRequestMsg) marshal() (x []byte) {
	if m.raw != nil {
		return m.raw
	}

	// See http://tools.ietf.org/html/rfc4346#section-7.4.4
	length := 1 + len(m.certificateTypes) + 2
	casLength := 0
	for _, ca := range m.certificateAuthorities {
		casLength += 2 + len(ca)
	}
	length += casLength

	if m.hasSignatureAndHash {
		length += 2 +2*len(m.supportedSignatureAlgorithms)
	}

	x = make([]byte, 4+length)
	x[0] = typeCertificateRequest
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)

	x[4] = uint8(len(m.certificateTypes))

	copy(x[5:], m.certificateTypes)
	y := x[5+len(m.certificateTypes):]

	if m.hasSignatureAndHash {
		n := len(m.supportedSignatureAlgorithms) * 2
		y[0] = uint8(n >> 8)
		y[1] = uint8(n)
		y = y[2:]
		for _, sigAlgo := range m.supportedSignatureAlgorithms {
			y[0] = uint8(sigAlgo >> 8)
			y[1] = uint8(sigAlgo)
			y = y[2:]
		}
	}

	y[0] = uint8(casLength >> 8)
	y[1] = uint8(casLength)
	y = y[2:]
	for _, ca := range m.certificateAuthorities {
		y[0] = uint8(len(ca) >> 8)
		y[1] = uint8(len(ca))
		y = y[2:]
		copy(y, ca)
		y = y[len(ca):]
	}

	m.raw = x
	return
}

func (m *certificateRequestMsg) unmarshal(data []byte) bool {
	m.raw = data

	if len(data) < 5 {
		return false
	}

	length := uint32(data[1])<<16 | uint32(data[2])<<8 | uint32(data[3])
	if uint32(len(data))-4 != length {
		return false
	}

	numCertTypes := int(data[4])
	data = data[5:]
	if numCertTypes == 0 || len(data) <= numCertTypes {
		return false
	}

	m.certificateTypes = make([]byte, numCertTypes)
	if copy(m.certificateTypes, data) != numCertTypes {
		return false
	}

	data = data[numCertTypes:]

	if m.hasSignatureAndHash {
		if len(data) < 2 {
			return false
		}
		sigAndHashLen := uint16(data[0])<<8 | uint16(data[1])
		data = data[2:]
		if sigAndHashLen&1 != 0 {
			return false
		}
		if len(data) < int(sigAndHashLen) {
			return false
		}
		numSigAlgos := sigAndHashLen / 2
		m.supportedSignatureAlgorithms = make([]SignatureScheme, numSigAlgos)
		for i := range m.supportedSignatureAlgorithms {
			m.supportedSignatureAlgorithms[i] = SignatureScheme(data[0])<<8 | SignatureScheme(data[1])
			data = data[2:]
		}
	}

	if len(data) < 2 {
		return false
	}
	casLength := uint16(data[0])<<8 | uint16(data[1])
	data = data[2:]
	if len(data) < int(casLength) {
		return false
	}
	cas := make([]byte, casLength)
	copy(cas, data)
	data = data[casLength:]

	m.certificateAuthorities = nil
	for len(cas) > 0 {
		if len(cas) < 2 {
			return false
		}
		caLen := uint16(cas[0])<<8 | uint16(cas[1])
		cas = cas[2:]

		if len(cas) < int(caLen) {
			return false
		}

		m.certificateAuthorities = append(m.certificateAuthorities, cas[:caLen])
		cas = cas[caLen:]
	}

	return len(data) == 0
}

type certificateVerifyMsg struct {
	raw                 []byte
	hasSignatureAndHash bool
	signatureAlgorithm    SignatureScheme
	signature           []byte
}

func (m *certificateVerifyMsg) equal(i interface{}) bool {
	m1, ok := i.(*certificateVerifyMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		m.hasSignatureAndHash == m1.hasSignatureAndHash &&
		m.signatureAlgorithm == m1.signatureAlgorithm &&
		bytes.Equal(m.signature, m1.signature)
}

func (m *certificateVerifyMsg) marshal() (x []byte) {
	if m.raw != nil {
		return m.raw
	}

	// See http://tools.ietf.org/html/rfc4346#section-7.4.8
	siglength := len(m.signature)
	length := 2 + siglength
	if m.hasSignatureAndHash {
		length += 2
	}
	x = make([]byte, 4+length)
	x[0] = typeCertificateVerify
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	y := x[4:]
	if m.hasSignatureAndHash {
		y[0] = uint8(m.signatureAlgorithm >> 8)
		y[1] = uint8(m.signatureAlgorithm)
		y = y[2:]
	}
	y[0] = uint8(siglength >> 8)
	y[1] = uint8(siglength)
	copy(y[2:], m.signature)

	m.raw = x

	return
}

func (m *certificateVerifyMsg) unmarshal(data []byte) bool {
	m.raw = data

	if len(data) < 6 {
		return false
	}

	length := uint32(data[1])<<16 | uint32(data[2])<<8 | uint32(data[3])
	if uint32(len(data))-4 != length {
		return false
	}

	data = data[4:]
	if m.hasSignatureAndHash {
		m.signatureAlgorithm = SignatureScheme(data[0])<<8 | SignatureScheme(data[1])
		data = data[2:]
	}

	if len(data) < 2 {
		return false
	}
	siglength := int(data[0])<<8 + int(data[1])
	data = data[2:]
	if len(data) != siglength {
		return false
	}

	m.signature = data

	return true
}

type newSessionTicketMsg struct {
	raw    []byte
	ticket []byte
}

func (m *newSessionTicketMsg) equal(i interface{}) bool {
	m1, ok := i.(*newSessionTicketMsg)
	if !ok {
		return false
	}

	return bytes.Equal(m.raw, m1.raw) &&
		bytes.Equal(m.ticket, m1.ticket)
}

func (m *newSessionTicketMsg) marshal() (x []byte) {
	if m.raw != nil {
		return m.raw
	}

	// See http://tools.ietf.org/html/rfc5077#section-3.3
	ticketLen := len(m.ticket)
	length := 2 + 4 + ticketLen
	x = make([]byte, 4+length)
	x[0] = typeNewSessionTicket
	x[1] = uint8(length >> 16)
	x[2] = uint8(length >> 8)
	x[3] = uint8(length)
	x[8] = uint8(ticketLen >> 8)
	x[9] = uint8(ticketLen)
	copy(x[10:], m.ticket)

	m.raw = x

	return
}

func (m *newSessionTicketMsg) unmarshal(data []byte) bool {
	m.raw = data

	if len(data) < 10 {
		return false
	}

	length := uint32(data[1])<<16 | uint32(data[2])<<8 | uint32(data[3])
	if uint32(len(data))-4 != length {
		return false
	}

	ticketLen := int(data[8])<<8 + int(data[9])
	if len(data)-10 != ticketLen {
		return false
	}

	m.ticket = data[10:]

	return true
}

type helloRequestMsg struct {
}

func (*helloRequestMsg) marshal() []byte {
	return []byte{typeHelloRequest, 0, 0, 0}
}

func (*helloRequestMsg) unmarshal(data []byte) bool {
	return len(data) == 4
}

func eqUint16s(x, y []uint16) bool {
	if len(x) != len(y) {
		return false
	}
	for i, v := range x {
		if y[i] != v {
			return false
		}
	}
	return true
}

func eqCurveIDs(x, y []CurveID) bool {
	if len(x) != len(y) {
		return false
	}
	for i, v := range x {
		if y[i] != v {
			return false
		}
	}
	return true
}

func eqStrings(x, y []string) bool {
	if len(x) != len(y) {
		return false
	}
	for i, v := range x {
		if y[i] != v {
			return false
		}
	}
	return true
}

func eqByteSlices(x, y [][]byte) bool {
	if len(x) != len(y) {
		return false
	}
	for i, v := range x {
		if !bytes.Equal(v, y[i]) {
			return false
		}
	}
	return true
}

func  eqSignatureAlgorithms(x, y []SignatureScheme) bool  {
	if len(x) != len(y) {
		return false
	}
	for i, v := range x {
		if v != y[i] {
			return false
		}
	}
	return true
}