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calculate PublicHeader length for packets with VersionFlag and ResetFlag

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This commit is contained in:
Marten Seemann
2016-11-08 09:21:27 +07:00
parent 6c0a885a0e
commit 756a421065
3 changed files with 66 additions and 24 deletions
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2
packet_packer.go
View File

@@ -74,7 +74,7 @@ func (p *packetPacker) packPacket(stopWaitingFrame *frames.StopWaitingFrame, lea
DiversificationNonce: p.cryptoSetup.DiversificationNonce(),
}
publicHeaderLength, err := responsePublicHeader.GetLength()
publicHeaderLength, err := responsePublicHeader.GetLength(p.perspective)
if err != nil {
return nil, err
}

37
public_header.go
View File

@@ -11,11 +11,11 @@ import (
)
var (
errPacketNumberLenNotSet = errors.New("PublicHeader: PacketNumberLen not set")
errResetAndVersionFlagSet = errors.New("PublicHeader: Reset Flag and Version Flag should not be set at the same time")
errReceivedTruncatedConnectionID = qerr.Error(qerr.InvalidPacketHeader, "receiving packets with truncated ConnectionID is not supported")
errInvalidConnectionID = qerr.Error(qerr.InvalidPacketHeader, "connection ID cannot be 0")
errGetLengthOnlyForRegularPackets = errors.New("PublicHeader: GetLength can only be called for regular packets")
errPacketNumberLenNotSet = errors.New("PublicHeader: PacketNumberLen not set")
errResetAndVersionFlagSet = errors.New("PublicHeader: Reset Flag and Version Flag should not be set at the same time")
errReceivedTruncatedConnectionID = qerr.Error(qerr.InvalidPacketHeader, "receiving packets with truncated ConnectionID is not supported")
errInvalidConnectionID = qerr.Error(qerr.InvalidPacketHeader, "connection ID cannot be 0")
errGetLengthNotForVersionNegotiation = errors.New("PublicHeader: GetLength cannot be called for VersionNegotiation packets")
)
// The PublicHeader of a QUIC packet
@@ -192,20 +192,35 @@ func ParsePublicHeader(b io.ByteReader, packetSentBy protocol.Perspective) (*Pub
// GetLength gets the length of the publicHeader in bytes
// can only be called for regular packets
func (h *PublicHeader) GetLength() (protocol.ByteCount, error) {
if h.VersionFlag || h.ResetFlag {
return 0, errGetLengthOnlyForRegularPackets
func (h *PublicHeader) GetLength(pers protocol.Perspective) (protocol.ByteCount, error) {
if h.VersionFlag && h.ResetFlag {
return 0, errResetAndVersionFlagSet
}
if h.VersionFlag && pers == protocol.PerspectiveServer {
return 0, errGetLengthNotForVersionNegotiation
}
length := protocol.ByteCount(1) // 1 byte for public flags
if h.PacketNumberLen != protocol.PacketNumberLen1 && h.PacketNumberLen != protocol.PacketNumberLen2 && h.PacketNumberLen != protocol.PacketNumberLen4 && h.PacketNumberLen != protocol.PacketNumberLen6 {
return 0, errPacketNumberLenNotSet
if h.hasPacketNumber(pers) {
if h.PacketNumberLen != protocol.PacketNumberLen1 && h.PacketNumberLen != protocol.PacketNumberLen2 && h.PacketNumberLen != protocol.PacketNumberLen4 && h.PacketNumberLen != protocol.PacketNumberLen6 {
return 0, errPacketNumberLenNotSet
}
length += protocol.ByteCount(h.PacketNumberLen)
}
if !h.TruncateConnectionID {
length += 8 // 8 bytes for the connection ID
}
// Version Number in packets sent by the client
if h.VersionFlag {
length += 4
}
length += protocol.ByteCount(len(h.DiversificationNonce))
length += protocol.ByteCount(h.PacketNumberLen)
return length, nil
}

51
public_header_test.go
View File

@@ -269,14 +269,17 @@ var _ = Describe("Public Header", func() {
Context("GetLength", func() {
It("errors when calling GetLength for Version Negotiation packets", func() {
hdr := PublicHeader{VersionFlag: true}
_, err := hdr.GetLength()
Expect(err).To(MatchError(errGetLengthOnlyForRegularPackets))
_, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).To(MatchError(errGetLengthNotForVersionNegotiation))
})
It("errors when calling GetLength for Public Reset packets", func() {
hdr := PublicHeader{ResetFlag: true}
_, err := hdr.GetLength()
Expect(err).To(MatchError(errGetLengthOnlyForRegularPackets))
It("errors when calling GetLength for packets that have the VersionFlag and the ResetFlag set", func() {
hdr := PublicHeader{
ResetFlag: true,
VersionFlag: true,
}
_, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).To(MatchError(errResetAndVersionFlagSet))
})
It("errors when PacketNumberLen is not set", func() {
@@ -284,7 +287,7 @@ var _ = Describe("Public Header", func() {
ConnectionID: 0x4cfa9f9b668619f6,
PacketNumber: 0xDECAFBAD,
}
_, err := hdr.GetLength()
_, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).To(MatchError(errPacketNumberLenNotSet))
})
@@ -294,11 +297,25 @@ var _ = Describe("Public Header", func() {
PacketNumber: 0xDECAFBAD,
PacketNumberLen: protocol.PacketNumberLen6,
}
length, err := hdr.GetLength()
length, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).ToNot(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 8 + 6))) // 1 byte public flag, 8 bytes connectionID, and packet number
})
It("gets the lengths of a packet sent by the client with the VersionFlag set", func() {
hdr := PublicHeader{
ConnectionID: 0x4cfa9f9b668619f6,
TruncateConnectionID: true,
PacketNumber: 0xDECAFBAD,
PacketNumberLen: protocol.PacketNumberLen6,
VersionFlag: true,
VersionNumber: protocol.Version36,
}
length, err := hdr.GetLength(protocol.PerspectiveClient)
Expect(err).ToNot(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 4 + 6))) // 1 byte public flag, 4 version number, and packet number
})
It("gets the length of a packet with longest packet number length and truncated connectionID", func() {
hdr := PublicHeader{
ConnectionID: 0x4cfa9f9b668619f6,
@@ -306,7 +323,7 @@ var _ = Describe("Public Header", func() {
PacketNumber: 0xDECAFBAD,
PacketNumberLen: protocol.PacketNumberLen6,
}
length, err := hdr.GetLength()
length, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).ToNot(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 6))) // 1 byte public flag, and packet number
})
@@ -317,7 +334,7 @@ var _ = Describe("Public Header", func() {
PacketNumber: 0xDECAFBAD,
PacketNumberLen: protocol.PacketNumberLen2,
}
length, err := hdr.GetLength()
length, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).ToNot(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 8 + 2))) // 1 byte public flag, 8 byte connectionID, and packet number
})
@@ -327,9 +344,19 @@ var _ = Describe("Public Header", func() {
DiversificationNonce: []byte("foo"),
PacketNumberLen: protocol.PacketNumberLen1,
}
length, err := hdr.GetLength()
length, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).NotTo(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 8 + 3 + 1)))
Expect(length).To(Equal(protocol.ByteCount(1 + 8 + 3 + 1))) // 1 byte public flag, 8 byte connectionID, 3 byte DiversificationNonce, 1 byte PacketNumber
})
It("gets the length of a PublicReset", func() {
hdr := PublicHeader{
ResetFlag: true,
ConnectionID: 0x4cfa9f9b668619f6,
}
length, err := hdr.GetLength(protocol.PerspectiveServer)
Expect(err).NotTo(HaveOccurred())
Expect(length).To(Equal(protocol.ByteCount(1 + 8))) // 1 byte public flag, 8 byte connectionID
})
})