Converts binary representation label to integer.

Parameters:buf -- Binary representation of label.
Returns:MPLS Label and BoS bit.
ryu.lib.packet.mpls.label_to_bin(mpls_label, is_bos=True)

Converts integer label to binary representation.

  • mpls_label -- MPLS Label.
  • is_bos -- BoS bit.

Binary representation of label.

class ryu.lib.packet.mpls.mpls(label=0, exp=0, bsb=1, ttl=255)

MPLS (RFC 3032) header encoder/decoder class.

NOTE: When decoding, this implementation assumes that the inner protocol is IPv4.

An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order.

Attribute Description
label Label Value
exp Experimental Use
bsb Bottom of Stack
ttl Time To Live
classmethod parser(buf)

Decode a protocol header.

This method is used only when decoding a packet.

Decode a protocol header at offset 0 in bytearray buf. Returns the following three objects.

  • An object to describe the decoded header.
  • A packet_base.PacketBase subclass appropriate for the rest of the packet. None when the rest of the packet should be considered as raw payload.
  • The rest of packet.
serialize(payload, prev)

Encode a protocol header.

This method is used only when encoding a packet.

Encode a protocol header. Returns a bytearray which contains the header.

payload is the rest of the packet which will immediately follow this header.

prev is a packet_base.PacketBase subclass for the outer protocol header. prev is None if the current header is the outer-most. For example, prev is ipv4 or ipv6 for tcp.serialize.