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add support for flowspec redirect-to-nexthop ipv4
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exabgp currently supports draft-simpson-idr-flowspec-redirect. This adds
support for the newer draft of that standard, draft-ietf-idr-flowspec-redirect-ip.

Since the drafts are incompatible, this is configured via a new
'redirect-to-nexthop-ietf' option.

This commit is ipv4 only and slots in easily with exabgp's existing
infrastructure
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@elindsey
elindsey committed Sep 27, 2019
1 parent fc69031 commit d14d37d
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Showing 7 changed files with 96 additions and 47 deletions.
2 changes: 2 additions & 0 deletions doc/man/exabgp.1
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Expand Up @@ -348,6 +348,8 @@ The Accumulated IGP Metric Attribute for BGP
Rules for IPv6
.It draft-simpson-idr-flowspec-redirect-00 (-02)
BGP Flow-Spec Redirect to IP Action
.It draft-ietf-idr-flowspec-redirect-00 (-02)
BGP Flow-Spec Redirect to IP Action
.It draft-ietf-idr-add-paths-08 (-10)
Advertisement of Multiple Paths in BGP
.It draft-ietf-idr-bgp-multisession-07 (??)
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1 change: 1 addition & 0 deletions doc/man/exabgp.conf.5
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Expand Up @@ -127,6 +127,7 @@ group <groupname> {
rate-limit <ratelimit>;
redirect ( <route-distinguisher> | <ip-address> );
redirect-to-nexthop; // Ref. next-hop above
redirect-to-nexthop-ietf <ip-address>;
copy <ip-address>;
mark <mark>;
action ( sample | terminal | sample-terminal );
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1 change: 1 addition & 0 deletions lib/exabgp/bgp/message/update/attribute/community/extended/__init__.py
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Expand Up @@ -27,6 +27,7 @@
from exabgp.bgp.message.update.attribute.community.extended.traffic import TrafficRedirect
from exabgp.bgp.message.update.attribute.community.extended.traffic import TrafficRedirectASN4
from exabgp.bgp.message.update.attribute.community.extended.traffic import TrafficMark
from exabgp.bgp.message.update.attribute.community.extended.traffic import TrafficNextHopIPv4IETF
from exabgp.bgp.message.update.attribute.community.extended.traffic import TrafficNextHopSimpson
from exabgp.bgp.message.update.attribute.community.extended.encapsulation import Encapsulation
from exabgp.bgp.message.update.attribute.community.extended.chso import ConsistentHashSortOrder
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35 changes: 34 additions & 1 deletion lib/exabgp/bgp/message/update/attribute/community/extended/traffic.py
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Expand Up @@ -10,6 +10,7 @@
from struct import pack
from struct import unpack

from exabgp.protocol.ip import IPv4
from exabgp.bgp.message.open.asn import ASN
from exabgp.bgp.message.open.capability.asn4 import ASN4
from exabgp.bgp.message.update.attribute.community.extended import ExtendedCommunity
Expand Down Expand Up @@ -96,7 +97,7 @@ def unpack (data):


# ============================================================== TrafficRedirect
# RFC 5575
# RFC 5575 and 7674

@ExtendedCommunity.register
class TrafficRedirect (ExtendedCommunity):
Expand Down Expand Up @@ -182,6 +183,38 @@ def unpack (data):
dscp, = unpack('!B',data[7:8])
return TrafficMark(dscp,data[:8])

# =============================================================== TrafficNextHopIPv4IETF
# draft-ietf-idr-flowspec-redirect-02
# see RFC 4360 for ipv4 address specific extended community format

@ExtendedCommunity.register
class TrafficNextHopIPv4IETF (ExtendedCommunity):
COMMUNITY_TYPE = 0x01
COMMUNITY_SUBTYPE = 0x0C

__slots__ = ['ip', 'copy']

def __init__ (self, ip, copy, community=None):
self.ip = ip
self.copy = copy
ExtendedCommunity.__init__(
self,
community if community is not None else pack(
"!2s4sH",
self._subtype(),
ip.pack(),
1 if copy else 0
)
)

def __repr__ (self):
return "copy-to-nexthop-ietf" if self.copy else "redirect-to-nexthop-ietf"

@staticmethod
def unpack (data):
ip, bit = unpack('!4sH', data[2:8])
return TrafficNextHopIPv4IETF(IPv4.ntop(ip), bool(bit & 0x01), data[:8])

# =============================================================== TrafficNextHopSimpson
# draft-simpson-idr-flowspec-redirect-02

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50 changes: 26 additions & 24 deletions lib/exabgp/configuration/announce/flow.py
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Expand Up @@ -38,6 +38,7 @@
from exabgp.configuration.flow.parser import rate_limit
from exabgp.configuration.flow.parser import redirect
from exabgp.configuration.flow.parser import redirect_next_hop
from exabgp.configuration.flow.parser import redirect_next_hop_ietf
from exabgp.configuration.flow.parser import copy
from exabgp.configuration.flow.parser import mark
from exabgp.configuration.flow.parser import action
Expand Down Expand Up @@ -106,17 +107,18 @@ class AnnounceFlow (ParseAnnounce):
'fragment': fragment,
'flow-label': flow_label,

'accept': accept,
'discard': discard,
'rate-limit': rate_limit,
'redirect': redirect,
'redirect-to-nexthop': redirect_next_hop,
'copy': copy,
'mark': mark,
'action': action,
'community': community,
'large-community': large_community,
'extended-community': extended_community,
'accept': accept,
'discard': discard,
'rate-limit': rate_limit,
'redirect': redirect,
'redirect-to-nexthop': redirect_next_hop,
'redirect-to-nexthop-ietf': redirect_next_hop_ietf,
'copy': copy,
'mark': mark,
'action': action,
'community': community,
'large-community': large_community,
'extended-community': extended_community,

'interface-set': interface_set,
}
Expand Down Expand Up @@ -145,19 +147,19 @@ class AnnounceFlow (ParseAnnounce):
'traffic-class': 'nlri-add',
'flow-label': 'nlri-add',

'accept': 'nop',
'discard': 'attribute-add',
'rate-limit': 'attribute-add',
'redirect': 'nexthop-and-attribute',
'redirect-to-nexthop': 'attribute-add',
'copy': 'nexthop-and-attribute',
'mark': 'attribute-add',
'action': 'attribute-add',
'community': 'attribute-add',
'large-community': 'attribute-add',
'extended-community': 'attribute-add',

'interface-set': 'attribute-add',
'accept': 'nop',
'discard': 'attribute-add',
'rate-limit': 'attribute-add',
'redirect': 'nexthop-and-attribute',
'redirect-to-nexthop': 'attribute-add',
'redirect-to-nexthop-ietf': 'attribute-add',
'copy': 'nexthop-and-attribute',
'mark': 'attribute-add',
'action': 'attribute-add',
'community': 'attribute-add',
'large-community': 'attribute-add',
'extended-community': 'attribute-add',
'interface-set': 'attribute-add',
}

assign = dict()
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7 changes: 7 additions & 0 deletions lib/exabgp/configuration/flow/parser.py
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Expand Up @@ -37,6 +37,7 @@
from exabgp.bgp.message.update.attribute.community.extended import TrafficRedirect
from exabgp.bgp.message.update.attribute.community.extended import TrafficRedirectASN4
from exabgp.bgp.message.update.attribute.community.extended import TrafficMark
from exabgp.bgp.message.update.attribute.community.extended import TrafficNextHopIPv4IETF
from exabgp.bgp.message.update.attribute.community.extended import TrafficNextHopSimpson

from exabgp.bgp.message.update.attribute.community.extended import InterfaceSet
Expand Down Expand Up @@ -296,6 +297,12 @@ def redirect (tokeniser):
def redirect_next_hop (tokeniser):
return ExtendedCommunities().add(TrafficNextHopSimpson(False))

def redirect_next_hop_ietf (tokeniser):
ip = IP.create(tokeniser())
if ip.ipv4():
return ExtendedCommunities().add(TrafficNextHopIPv4IETF(ip, False))
else:
raise ValueError('ipv6 address not supported %s' % ip)

def copy (tokeniser):
return IP.create(tokeniser()),ExtendedCommunities().add(TrafficNextHopSimpson(True))
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47 changes: 25 additions & 22 deletions lib/exabgp/configuration/flow/then.py
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Expand Up @@ -14,6 +14,7 @@
from exabgp.configuration.flow.parser import rate_limit
from exabgp.configuration.flow.parser import redirect
from exabgp.configuration.flow.parser import redirect_next_hop
from exabgp.configuration.flow.parser import redirect_next_hop_ietf
from exabgp.configuration.flow.parser import copy
from exabgp.configuration.flow.parser import mark
from exabgp.configuration.flow.parser import action
Expand Down Expand Up @@ -43,33 +44,35 @@ class ParseFlowThen (Section):
'}' % ';\n '.join(definition)

known = {
'accept': accept,
'discard': discard,
'rate-limit': rate_limit,
'redirect': redirect,
'redirect-to-nexthop': redirect_next_hop,
'copy': copy,
'mark': mark,
'action': action,
'community': community,
'large-community': large_community,
'extended-community': extended_community,
'accept': accept,
'discard': discard,
'rate-limit': rate_limit,
'redirect': redirect,
'redirect-to-nexthop': redirect_next_hop,
'redirect-to-nexthop-ietf': redirect_next_hop_ietf,
'copy': copy,
'mark': mark,
'action': action,
'community': community,
'large-community': large_community,
'extended-community': extended_community,
}

# 'community','extended-community'

action = {
'accept': 'nop',
'discard': 'attribute-add',
'rate-limit': 'attribute-add',
'redirect': 'nexthop-and-attribute',
'redirect-to-nexthop': 'attribute-add',
'copy': 'nexthop-and-attribute',
'mark': 'attribute-add',
'action': 'attribute-add',
'community': 'attribute-add',
'large-community': 'attribute-add',
'extended-community': 'attribute-add',
'accept': 'nop',
'discard': 'attribute-add',
'rate-limit': 'attribute-add',
'redirect': 'nexthop-and-attribute',
'redirect-to-nexthop': 'attribute-add',
'redirect-to-nexthop-ietf': 'attribute-add',
'copy': 'nexthop-and-attribute',
'mark': 'attribute-add',
'action': 'attribute-add',
'community': 'attribute-add',
'large-community': 'attribute-add',
'extended-community': 'attribute-add',
}

name = 'flow/then'
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