VRRP¶

VRRP packet parser/serializer

[RFC 3768] VRRP v2 packet format:

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Type  | Virtual Rtr ID|   Priority    | Count IP Addrs|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   Auth Type   |   Adver Int   |          Checksum             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         IP Address (1)                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            .                                  |
|                            .                                  |
|                            .                                  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         IP Address (n)                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                     Authentication Data (1)                   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                     Authentication Data (2)                   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

[RFC 5798] VRRP v3 packet format:

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    IPv4 Fields or IPv6 Fields                 |
...                                                             ...
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |Version| Type  | Virtual Rtr ID|   Priority    |Count IPvX Addr|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |(rsvd) |     Max Adver Int     |          Checksum             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                                                               +
 |                       IPvX Address(es)                        |
 +                                                               +
 +                                                               +
 +                                                               +
 +                                                               +
 |                                                               |
 +                                                               +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

class os_ken.lib.packet.vrrp.vrrp(version, type_, vrid, priority, count_ip, max_adver_int, checksum, ip_addresses, auth_type=None, auth_data=None)¶

The base class for VRRPv2 (RFC 3768) and VRRPv3 (RFC 5798) header encoder/decoder classes.

Unlike other os_ken.lib.packet.packet_base.PacketBase derived classes, This class should not be directly instantiated by user.

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

Attribute	Description
version	Version
type	Type
vrid	Virtual Rtr ID (VRID)
priority	Priority
count_ip	Count IPvX Addr. Calculated automatically when encoding.
max_adver_int	Maximum Advertisement Interval (Max Adver Int)
checksum	Checksum. Calculated automatically when encoding.
ip_addresses	IPvX Address(es). A python list of IP addresses.
auth_type	Authentication Type (only for VRRPv2)
auth_data	Authentication Data (only for VRRPv2)

create_packet(primary_ip_address, vlan_id=None)¶

Prepare a VRRP packet.

Returns a newly created os_ken.lib.packet.packet.Packet object with appropriate protocol header objects added by add_protocol(). It's caller's responsibility to serialize(). The serialized packet would looks like the ones described in the following sections.

• RFC 3768 5.1. VRRP Packet Format
• RFC 5798 5.1. VRRP Packet Format

Argument	Description
primary_ip_address	Source IP address
vlan_id	VLAN ID. None for no VLAN.

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.

class os_ken.lib.packet.vrrp.vrrpv2(version, type_, vrid, priority, count_ip, max_adver_int, checksum, ip_addresses, auth_type=None, auth_data=None)¶

VRRPv2 (RFC 3768) header encoder/decoder class.

Unlike other os_ken.lib.packet.packet_base.PacketBase derived classes, create method should be used to instantiate an object of this class.

static create(type_, vrid, priority, max_adver_int, ip_addresses)¶

Unlike other os_ken.lib.packet.packet_base.PacketBase derived classes, this method should be used to instantiate an object of this class.

This method's arguments are same as os_ken.lib.packet.vrrp.vrrp object's attributes of the same name. (except that type_ corresponds to type attribute.)

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.

class os_ken.lib.packet.vrrp.vrrpv3(version, type_, vrid, priority, count_ip, max_adver_int, checksum, ip_addresses, auth_type=None, auth_data=None)¶

VRRPv3 (RFC 5798) header encoder/decoder class.

Unlike other os_ken.lib.packet.packet_base.PacketBase derived classes, create method should be used to instantiate an object of this class.

static create(type_, vrid, priority, max_adver_int, ip_addresses)¶

Unlike other os_ken.lib.packet.packet_base.PacketBase derived classes, this method should be used to instantiate an object of this class.

This method's arguments are same as os_ken.lib.packet.vrrp.vrrp object's attributes of the same name. (except that type_ corresponds to type attribute.)

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.