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proxy: fix the marshalling of the UDP frames

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- the initial length field should be the total length of the whole
  frame including the variable length field and including the length
  field
- when unmarshalling, return the number of bytes of payload actually
  unmarshalled and not the size of the unmarshal buffer

Signed-off-by: David Scott <dave.scott@docker.com>
This commit is contained in:
David Scott 2016-04-22 15:17:56 +01:00
parent e940e12abc
commit 610dac2fb7
1 changed files with 28 additions and 17 deletions
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45
alpine/packages/proxy/libproxy/udp_encapsulation.go
View File

@ -47,11 +47,12 @@ func (u *udpEncapsulator) ReadFromUDP(b []byte) (int, *net.UDPAddr, error) {
u.r.Lock()
defer u.r.Unlock()
datagram := &udpDatagram{payload: b}
err = datagram.Unmarshal(conn)
length, err := datagram.Unmarshal(conn)
if err != nil {
return 0, nil, err
}
return len(datagram.payload), &net.UDPAddr{IP: *datagram.IP, Port: int(datagram.Port), Zone: datagram.Zone}, nil
udpAddr := net.UDPAddr{IP: *datagram.IP, Port: int(datagram.Port), Zone: datagram.Zone}
return length, &udpAddr, nil
}
func (u *udpEncapsulator) WriteToUDP(b []byte, addr *net.UDPAddr) (int, error) {
@ -76,10 +77,14 @@ func (u *udpEncapsulator) Close() error {
func NewUDPListener(listener net.Listener) udpListener {
var m sync.Mutex;
var r sync.Mutex;
var w sync.Mutex;
return &udpEncapsulator{
conn: nil,
listener: listener,
m: &m,
r: &r,
w: &w,
}
}
@ -98,24 +103,30 @@ func (u *udpDatagram) Marshal(conn net.Conn) error {
if err := binary.Write(&header, binary.LittleEndian, &length); err != nil {
return err
}
if err := binary.Write(&header, binary.LittleEndian, &u.IP); err != nil {
if err := binary.Write(&header, binary.LittleEndian, u.IP); err != nil {
return err
}
if err := binary.Write(&header, binary.LittleEndian, &u.Port); err != nil {
return err
}
length = uint16(len(u.Zone))
if err := binary.Write(&header, binary.LittleEndian, &length); err != nil {
return err
}
if err := binary.Write(&header, binary.LittleEndian, &u.Zone); err != nil {
if err := binary.Write(&header, binary.LittleEndian, []byte(u.Zone)); err != nil {
return nil
}
length = uint16(len(u.payload))
if err := binary.Write(&header, binary.LittleEndian, &length); err != nil {
return nil
}
length = uint16(header.Len() + len(u.payload))
length = uint16(2 + header.Len() + len(u.payload))
if err := binary.Write(conn, binary.LittleEndian, &length); err != nil {
return nil
}
@ -131,38 +142,38 @@ func (u *udpDatagram) Marshal(conn net.Conn) error {
return nil
}
func (u *udpDatagram) Unmarshal(conn net.Conn) error {
func (u *udpDatagram) Unmarshal(conn net.Conn) (int, error) {
var length uint16
// frame length
if err := binary.Read(conn, binary.LittleEndian, &length); err != nil {
return err
return 0, err
}
if err := binary.Read(conn, binary.LittleEndian, &length); err != nil {
return err
return 0, err
}
var IP net.IP
IP = make([]byte, length)
if err := binary.Read(conn, binary.LittleEndian, &IP); err != nil {
return err
return 0, err
}
u.IP = &IP
if err := binary.Read(conn, binary.LittleEndian, &u.Port); err != nil {
return err
return 0, err
}
if err := binary.Read(conn, binary.LittleEndian, &length); err != nil {
return err
return 0, err
}
Zone := make([]byte, length)
if err := binary.Read(conn, binary.LittleEndian, &Zone); err != nil {
return err
return 0, err
}
u.Zone = string(Zone)
if err := binary.Read(conn, binary.LittleEndian, &length); err != nil {
return err
return 0, err
}
u.payload = make([]byte, length)
if err := binary.Read(conn, binary.LittleEndian, &u.payload); err != nil {
return err
_, err := io.ReadFull(conn, u.payload[0:length])
if err != nil {
return 0, err
}
return nil
return int(length), nil
}