ipmininet.router.config.exabgp module¶

class ipmininet.router.config.exabgp.BGPAttribute(attr_type: Union[str, int], val: Union[HexRepresentable, int, str], flags: Optional[BGPAttributeFlags] = None)¶

Bases: ipmininet.router.config.exabgp.Representable

A BGP attribute as represented in ExaBGP. Either the Attribute is known from ExaBGP and so the class uses its string representation. Or the attribute is not known, then the class uses its hexadecimal representation. The latter representation is also useful to modify flags of already known attributes. For example the MED value is a known attribute which is not transitive. By passing a BGPAttributeFlags object to the constructor, it is now possible to make is transitive with BGPAttributeFlags(1, 1, 0, 0) (both optional and transitive bits are set to 1)

Constructs an Attribute known from ExaBGP or an unknown attribute if flags is not None. It raises a ValueError if the initialisation of BGPAttribute fails. Either because type_attr is not an int (for an unknown attribute), or the string of type_attr is not recognised by ExaBGP (for a known attribute)

Parameters:

attr_type – In the case of a Known attribute, attr_type is a valid string recognised by ExaBGP. In the case of an unknown attribute, attr_type is the integer ID of the attribute. If attr_type is a string it must be a valid string recognized by ExaBGP. Valid strings are: ‘next-hop’, ‘origin’, ‘med’, ‘as-path’, ‘local-preference’, ‘atomic-aggregate’, ‘aggregator’, ‘originator-id’, ‘cluster-list’,’community’, ‘large-community’, ‘extended-community’, ‘name’, ‘aigp’
val – The actual value of the attribute
flags – If None, the BGPAttribute object contains a known attribute from ExaBGP. In this case, the representation of this attribute will be a string. If flags is an instance of BGPAttribute, the hexadecimal representation will be used

hex_repr() → str¶

str_repr() → str¶

class ipmininet.router.config.exabgp.BGPAttributeFlags(optional, transitive, partial, extended)¶

Bases: ipmininet.router.config.exabgp.HexRepresentable

Represents the flags part of a BGP attribute (RFC 4271 section 4.3) The flags are an 8-bits integer value in the form O T P E 0 0 0 0. When :

bit O is set to 0: the attribute is Well-Known. If 1, it is optional
bit T is set to 0: the attribute is not Transitive. If 1, it is transitive
bit P is set to 0: the attribute is complete; If 1, partial
bit E is set to 0: the attribute is of length < 256 bits. If set to 1: 256 <= length < 2^{16}

The last 4 bits are unused

This class is notably used to define new attributes unknown from ExaBGP or change the flags of a already known attribute. For example, the MED value is not transitive. To make it transitive, put the transitive bit to 1.

hex_repr()¶

Returns:	The Hexadecimal representation of an BGP attribute value

static to_hex_flags(a, b, c, d)¶

class ipmininet.router.config.exabgp.BGPRoute(network: ipmininet.router.config.exabgp.Representable, attributes: Sequence[BGPAttribute])¶

Bases: ipmininet.router.config.exabgp.Representable

A BGP route as represented in ExaBGP

class ipmininet.router.config.exabgp.ExaBGPDaemon(node, port=179, *args, **kwargs)¶

Bases: ipmininet.router.config.bgp.AbstractBGP

KILL_PATTERNS = ('exabgp',)¶

NAME = 'exabgp'¶

STARTUP_LINE_EXTRA¶

build()¶

Build the configuration tree for this daemon

Returns:	ConfigDict-like object describing this configuration

cfg_filenames¶: Return the list of filenames in which this daemon config should be stored

dry_run¶: The startup line to use to check that the daemon is well-configured

env_filename¶

set_defaults(defaults)¶

Modifies the default configuration of this ExaBGP daemon

Parameters:

env –
a dictionary of all the environment variables that configure ExaBGP. Type “exabgp –help” to take a look on every environment variable. env.tcp.delay is set by default to 2 min as FRRouting BGPD daemon seems to reject routes if ExaBGP injects routes to early. Each environment variable is either a string or an int.

The following environment variable are set :
- daemon.user = ‘root’
- daemon.drop = ‘false’
- daemon.daemonize = ‘false’
- daemon.pid = <default configuration folder /tmp/exabgp_<node>.pid>
- log.level = ‘CRIT’
- log.destination = <default configuration folder /tmp/exabgp_<node>.log>
- log.reactor = ‘false’
- log.processes = false’
- log.network = ‘false’
- api.cli = ‘false’
- tcp.delay = 2 # waits at most 2 minutes
address_families – the routes to inject for both IPv4 and IPv6 unicast AFI.
passive – Tells to ExaBGP to not send active BGP Open messages. The daemon waits until the remote peer sends first the Open message to start the BGP session. Its default value is set to True.

startup_line¶: Return the corresponding startup_line for this daemon

template_filenames¶

class ipmininet.router.config.exabgp.ExaList(lst: List[Union[str, int]])¶

Bases: ipmininet.router.config.exabgp.HexRepresentable

List that can be represented in a form of string for BGP routes attributes. This class is only used for string representable attribute. That is attribute already defined and known from ExaBGP. If the list is used for an hexadecimal attribute, it raises a ValueError

hex_repr() → str¶

Returns:	The Hexadecimal representation of an BGP attribute value

val¶

class ipmininet.router.config.exabgp.HexRepresentable¶

Bases: ipmininet.router.config.exabgp.Representable

Representation of an hexadecimal value for ExaBGP.

In the case of an unknown ExaBGP attribute, the value cannot be interpreted by ExaBGP. Then it is needed to use its hexadecimal representation. This Abstract class must be implemented by any “unrepresentable” BGP attribute.

Example

Imagine you want to represent a new 64-bits attribute. All you have to do is to extend the HexRepresentable class and then create a new BGPAttribute as usual. The following code shows an example:

class LongAttr(HexRepresentable):
    _uint64_max = 18446744073709551615

    def __init__(self, my_long):
        assert 0 <= my_long < LongAttr._uint64_max
        self.val = my_long

    def hex_repr(self):
        return '{0:#0{1}X}'.format(self.val, 18)

    def __str__(self):
        return self.hex_repr()

# your new attribute
my_new_attr = BGPAttribute(42, LongAttr(2658), BGPAttributesFlags(1,1,0,0))

hex_repr() → str¶

Returns:	The Hexadecimal representation of an BGP attribute value

class ipmininet.router.config.exabgp.Representable¶

Bases: abc.ABC

String representation for ExaBGP configuration Each sub-part of any ExaBGP route must be representable and must override the default __str__ function