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https://github.com/faucetsdn/ryu.git
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bgp: clean up codes which constructs an update message
Signed-off-by: ISHIDA Wataru <ishida.wataru@lab.ntt.co.jp> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
This commit is contained in:
ISHIDA Wataru
FUJITA Tomonori
parent
2eccc5da41
commit
68c13b7fa1
@ -588,14 +588,6 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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"""Construct update message with Outgoing-routes path attribute
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appropriately cloned/copied/updated.
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"""
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if self._neigh_conf.cap_mbgp_ipv4:
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update = self._construct_bgp4_update(outgoing_route)
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else:
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update = self._construct_mpbgp_update(outgoing_route)
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return update
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def _construct_bgp4_update(self, outgoing_route):
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update = None
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path = outgoing_route.path
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# Get copy of path's path attributes.
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@ -603,8 +595,14 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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new_pathattr = []
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if path.is_withdraw:
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update = BGPUpdate(withdrawn_routes=[path.nlri])
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return update
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if self._neigh_conf.cap_mbgp_ipv4:
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update = BGPUpdate(withdrawn_routes=[path.nlri])
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return update
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else:
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mpunreach_attr = BGPPathAttributeMpUnreachNLRI(
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path.route_family.afi, path.route_family.safi, [path.nlri]
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)
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new_pathattr.append(mpunreach_attr)
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else:
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# Supported and un-supported/unknown attributes.
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origin_attr = None
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@ -629,6 +627,15 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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nexthop_attr = BGPPathAttributeNextHop(next_hop)
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assert nexthop_attr, 'Missing NEXTHOP mandatory attribute.'
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if not self._neigh_conf.cap_mbgp_ipv4:
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# We construct mpreach-nlri attribute.
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mpnlri_attr = BGPPathAttributeMpReachNLRI(
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path.route_family.afi,
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path.route_family.safi,
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next_hop,
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nlri_list
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)
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# ORIGIN Attribute.
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# According to RFC this attribute value SHOULD NOT be changed by
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# any other speaker.
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@ -705,12 +712,27 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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if path_extcomm_attr:
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# SOO list can be configured per VRF and/or per Neighbor.
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# NeighborConf has this setting we add this to existing list.
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soo_list = path_extcomm_attr.soo_list
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communities = path_extcomm_attr.communities
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if self._neigh_conf.soo_list:
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soo_list.extend(self._neigh_conf.soo_list)
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#construct extended community
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soo_list = self._neigh_conf.soo_list
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subtype = 0x03
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for soo in soo_list:
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first, second = soo.split(':')
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if '.' in first:
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c = BGPIPv4AddressSpecificExtendedCommunity(
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subtype=subtype,
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ipv4_address=first,
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local_administrator=int(second))
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else:
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c = BGPTwoOctetAsSpecificExtendedCommunity(
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subtype=subtype,
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as_number=int(first),
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local_administrator=int(second))
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communities.append(c)
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extcomm_attr = BGPPathAttributeExtendedCommunities(
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path_extcomm_attr.rt_list,
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soo_list
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communities=communities
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)
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# UNKOWN Attributes.
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@ -720,158 +742,11 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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# Ordering path attributes according to type as RFC says. We set
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# MPReachNLRI first as advised by experts as a new trend in BGP
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# implementation.
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new_pathattr.append(nexthop_attr)
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new_pathattr.append(origin_attr)
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new_pathattr.append(aspath_attr)
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if multi_exit_disc:
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new_pathattr.append(multi_exit_disc)
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if localpref_attr:
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new_pathattr.append(localpref_attr)
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if community_attr:
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new_pathattr.append(community_attr)
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if extcomm_attr:
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new_pathattr.append(extcomm_attr)
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if unkown_opttrans_attrs:
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new_pathattr.extend(unkown_opttrans_attrs.values())
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update = BGPUpdate(path_attributes=new_pathattr,
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nlri=nlri_list)
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return update
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def _construct_mpbgp_update(self, outgoing_route):
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"""Construct update message with Outgoing-routes path attribute
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appropriately cloned/copied/updated.
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"""
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# TODO(PH): Investigate how this case needs to be handled for iBGP.
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update = None
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path = outgoing_route.path
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# Get copy of path's path attributes.
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pathattr_map = path.pathattr_map
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new_pathattr = []
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# If this is withdraw update we copy MpUnReach path-attribute and
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# create new Update message.
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if path.is_withdraw:
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# MP_UNREACH_NLRI Attribute.
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mpunreach_attr = BGPPathAttributeMpUnreachNLRI(
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path.route_family.afi, path.route_family.safi, [path.nlri]
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)
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new_pathattr.append(mpunreach_attr)
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else:
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# Supported and un-supported/unknown attributes.
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origin_attr = None
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aspath_attr = None
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mpnlri_attr = None
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extcomm_attr = None
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community_attr = None
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localpref_attr = None
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unkown_opttrans_attrs = None
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# MP_REACH_NLRI Attribute.
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# By default we use BGPS's interface IP with this peer as next_hop.
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# TODO(PH): change to use protocol's local address.
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# next_hop = self._neigh_conf.host_bind_ip
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next_hop = self._session_next_hop(path.route_family)
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# If this is a iBGP peer.
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if not self.is_ebgp_peer() and path.source is not None:
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# If the path came from a bgp peer and not from NC, according
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# to RFC 4271 we should not modify next_hop.
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next_hop = path.nexthop
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# We construct mpreach-nlri attribute.
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mpnlri_attr = BGPPathAttributeMpReachNLRI(
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path.route_family.afi,
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path.route_family.safi,
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next_hop,
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[path.nlri]
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)
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# ORIGIN Attribute.
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# According to RFC this attribute value SHOULD NOT be changed by
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# any other speaker.
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origin_attr = pathattr_map.get(BGP_ATTR_TYPE_ORIGIN)
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assert origin_attr, 'Missing ORIGIN mandatory attribute.'
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# AS_PATH Attribute.
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# Construct AS-path-attr using paths aspath attr. with local AS as
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# first item.
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path_aspath = pathattr_map.get(BGP_ATTR_TYPE_AS_PATH)
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assert path_aspath, 'Missing AS_PATH mandatory attribute.'
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# Deep copy aspath_attr value
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path_seg_list = path_aspath.path_seg_list
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# If this is a iBGP peer.
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if not self.is_ebgp_peer():
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# When a given BGP speaker advertises the route to an internal
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# peer, the advertising speaker SHALL NOT modify the AS_PATH
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# attribute associated with the route.
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aspath_attr = BGPPathAttributeAsPath(path_seg_list)
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if self._neigh_conf.cap_mbgp_ipv4:
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new_pathattr.append(nexthop_attr)
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else:
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# When a given BGP speaker advertises the route to an external
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# peer, the advertising speaker updates the AS_PATH attribute
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# as follows:
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# 1) if the first path segment of the AS_PATH is of type
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# AS_SEQUENCE, the local system prepends its own AS num as
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# the last element of the sequence (put it in the left-most
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# position with respect to the position of octets in the
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# protocol message). If the act of prepending will cause an
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# overflow in the AS_PATH segment (i.e., more than 255
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# ASes), it SHOULD prepend a new segment of type AS_SEQUENCE
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# and prepend its own AS number to this new segment.
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#
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# 2) if the first path segment of the AS_PATH is of type AS_SET
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# , the local system prepends a new path segment of type
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# AS_SEQUENCE to the AS_PATH, including its own AS number in
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# that segment.
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#
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# 3) if the AS_PATH is empty, the local system creates a path
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# segment of type AS_SEQUENCE, places its own AS into that
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# segment, and places that segment into the AS_PATH.
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if (len(path_seg_list) > 0 and
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isinstance(path_seg_list[0], list) and
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len(path_seg_list[0]) < 255):
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path_seg_list[0].insert(0, self._core_service.asn)
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else:
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path_seg_list.insert(0, [self._core_service.asn])
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aspath_attr = BGPPathAttributeAsPath(path_seg_list)
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new_pathattr.append(mpnlri_attr)
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# MULTI_EXIT_DISC Attribute.
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# For eBGP session we can send multi-exit-disc if configured.
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multi_exit_disc = None
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if self.is_ebgp_peer():
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multi_exit_disc = pathattr_map.get(
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BGP_ATTR_TYPE_MULTI_EXIT_DISC)
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# LOCAL_PREF Attribute.
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if not self.is_ebgp_peer():
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# For iBGP peers we are required to send local-pref attribute
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# for connected or local prefixes. We send default local-pref.
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localpref_attr = pathattr.LocalPref(100)
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# COMMUNITY Attribute.
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community_attr = pathattr_map.get(BGP_ATTR_TYPE_COMMUNITIES)
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# EXTENDED COMMUNITY Attribute.
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# Construct ExtCommunity path-attr based on given.
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path_extcomm_attr = pathattr_map.get(
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BGP_ATTR_TYPE_EXTENDED_COMMUNITIES
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)
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if path_extcomm_attr:
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# SOO list can be configured per VRF and/or per Neighbor.
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# NeighborConf has this setting we add this to existing list.
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soo_list = path_extcomm_attr.soo_list
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if self._neigh_conf.soo_list:
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soo_list.extend(self._neigh_conf.soo_list)
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extcomm_attr = BGPPathAttributeExtendedCommunities(
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path_extcomm_attr.rt_list+soo_list
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)
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# UNKOWN Attributes.
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# Get optional transitive path attributes
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unkown_opttrans_attrs = bgp_utils.get_unknow_opttrans_attr(path)
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# Ordering path attributes according to type as RFC says. We set
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# MPReachNLRI first as advised by experts as a new trend in BGP
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# implementation.
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new_pathattr.append(mpnlri_attr)
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new_pathattr.append(origin_attr)
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new_pathattr.append(aspath_attr)
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if multi_exit_disc:
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@ -885,8 +760,12 @@ class Peer(Source, Sink, NeighborConfListener, Activity):
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if unkown_opttrans_attrs:
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new_pathattr.extend(unkown_opttrans_attrs.values())
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update = BGPUpdate(path_attributes=new_pathattr)
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return update
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if self._neigh_conf.cap_mbgp_ipv4:
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update = BGPUpdate(path_attributes=new_pathattr,
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nlri=nlri_list)
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else:
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update = BGPUpdate(path_attributes=new_pathattr)
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return update
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def _connect_loop(self, client_factory):
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"""In the current greeenlet we try to establish connection with peer.
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