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correcty read PublicHeader of PublicReset packets

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This commit is contained in:
Marten Seemann
2016-11-07 21:26:25 +07:00
parent afa71d52f1
commit 56a287ab9c
6 changed files with 89 additions and 65 deletions
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60
public_header.go
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@@ -57,7 +57,7 @@ func (h *PublicHeader) Write(b *bytes.Buffer, version protocol.VersionNumber, pe
}
// only set PacketNumberLen bits if a packet number will be written
if !(h.ResetFlag || (pers == protocol.PerspectiveServer && h.VersionFlag)) {
if h.hasPacketNumber(pers) {
switch h.PacketNumberLen {
case protocol.PacketNumberLen1:
publicFlagByte |= 0x00
@@ -85,7 +85,7 @@ func (h *PublicHeader) Write(b *bytes.Buffer, version protocol.VersionNumber, pe
}
// if we're a server, and the VersionFlag is set, we must not include anything else in the packet
if h.ResetFlag || (pers == protocol.PerspectiveServer && h.VersionFlag) {
if !h.hasPacketNumber(pers) {
return nil
}
@@ -110,7 +110,8 @@ func (h *PublicHeader) Write(b *bytes.Buffer, version protocol.VersionNumber, pe
}
// ParsePublicHeader parses a QUIC packet's public header
func ParsePublicHeader(b io.ByteReader) (*PublicHeader, error) {
// the packetSentBy is the perspective of the peer that sent this PublicHeader, i.e. if we're the server, packetSentBy should be PerspectiveClient
func ParsePublicHeader(b io.ByteReader, packetSentBy protocol.Perspective) (*PublicHeader, error) {
header := &PublicHeader{}
// First byte
@@ -131,15 +132,17 @@ func ParsePublicHeader(b io.ByteReader) (*PublicHeader, error) {
return nil, errReceivedTruncatedConnectionID
}
switch publicFlagByte & 0x30 {
case 0x30:
header.PacketNumberLen = protocol.PacketNumberLen6
case 0x20:
header.PacketNumberLen = protocol.PacketNumberLen4
case 0x10:
header.PacketNumberLen = protocol.PacketNumberLen2
case 0x00:
header.PacketNumberLen = protocol.PacketNumberLen1
if header.hasPacketNumber(packetSentBy) {
switch publicFlagByte & 0x30 {
case 0x30:
header.PacketNumberLen = protocol.PacketNumberLen6
case 0x20:
header.PacketNumberLen = protocol.PacketNumberLen4
case 0x10:
header.PacketNumberLen = protocol.PacketNumberLen2
case 0x00:
header.PacketNumberLen = protocol.PacketNumberLen1
}
}
// Connection ID
@@ -147,23 +150,24 @@ func ParsePublicHeader(b io.ByteReader) (*PublicHeader, error) {
if err != nil {
return nil, err
}
header.ConnectionID = protocol.ConnectionID(connID)
if header.ConnectionID == 0 {
return nil, errInvalidConnectionID
}
if !header.ResetFlag {
// Version (optional)
if header.VersionFlag {
var versionTag uint32
versionTag, err = utils.ReadUint32(b)
if err != nil {
return nil, err
}
header.VersionNumber = protocol.VersionTagToNumber(versionTag)
// Version (optional)
if header.VersionFlag && !header.ResetFlag {
var versionTag uint32
versionTag, err = utils.ReadUint32(b)
if err != nil {
return nil, err
}
header.VersionNumber = protocol.VersionTagToNumber(versionTag)
}
// Packet number
// Packet number
if header.hasPacketNumber(packetSentBy) {
packetNumber, err := utils.ReadUintN(b, uint8(header.PacketNumberLen))
if err != nil {
return nil, err
@@ -192,3 +196,15 @@ func (h *PublicHeader) GetLength() (protocol.ByteCount, error) {
length += protocol.ByteCount(h.PacketNumberLen)
return length, nil
}
// hasPacketNumber determines if this PublicHeader will contain a packet number
// this depends on the ResetFlag, the VersionFlag and who sent the packet
func (h *PublicHeader) hasPacketNumber(packetSentBy protocol.Perspective) bool {
if h.ResetFlag {
return false
}
if h.VersionFlag && packetSentBy == protocol.PerspectiveServer {
return false
}
return true
}