A BGP update-group is dynamically created to group together a set of peers
such that any BGP updates can be formed just once for the entire group and
only the next hop attribute may need to be modified when the update is sent
out to each peer in the group. The update formation code attempts to
determine as much as possible if the next hop will be set to our own IP
address for every peer in the group. This helps to avoid additional checks
at the point of sending the update (which happens on a per-peer basis) and
also because some other attributes may/could vary depending on whether the
next hop is set to our own IP or not. Resetting the next hop to our own IP
address is the most common behavior for EBGP peerings in the absence of
other user-configured or internal (e.g., for l2vpn/evpn) settings and
peerings on a shared subnet.
The code had a flaw in the multiaccess check to see if there are peers in
the update group which are on a shared subnet as the next hop of the path
being announced - the source peer could itself be in the same update group
and cause the check to give an incorrect result. Modify the check to skip
the source peer so that the check is more accurate.
Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by: Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by: Don Slice <dslice@cumulusnetworks.com>
this command is missing, compared with 'match ipv6 next-hop' command
available. Adding it by taking into account the backward compatible
effect when supposing that some people have configured acls with name
being an ipv4 address.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
The bgp reason code was being reset in bgp_best_selection
by rerunning bgp_path_info_cmp multiple times under certain
receiving patterns of data from peers.
This is the debugs that show this issue:
2020/03/16 19:17:22.523780 BGP: 2001:20:1:1::6 rcvd UPDATE w/ attr: nexthop 20.1.1.6, origin i, metric 600, community 1000:1006, path 20
2020/03/16 19:17:22.523819 BGP: 2001:20:1:1::6 rcvd 20.10.0.6/32 IPv4 unicast
2020/03/16 19:17:22.556168 BGP: 20.1.1.6 rcvd UPDATE w/ attr: nexthop 20.1.1.6, origin i, metric 500, community 1000:1006, path 20
2020/03/16 19:17:22.556209 BGP: 20.1.1.6 rcvd 20.10.0.6/32 IPv4 unicast
2020/03/16 19:17:22.572358 BGP: bgp_process_main_one: p=20.10.0.6/32 afi=IPv4, safi=unicast start
2020/03/16 19:17:22.572408 BGP: 20.10.0.6/32: Comparing path 2001:20:1:1::6 flags 0x410 with path 20.1.1.6 flags 0x410
2020/03/16 19:17:22.572415 BGP: 20.10.0.6/32: path 2001:20:1:1::6 loses to path 20.1.1.6 due to MED 600 > 500
2020/03/16 19:17:22.572422 BGP: 20.10.0.6/32: path 20.1.1.6 is the bestpath from AS 20
2020/03/16 19:17:22.572429 BGP: 20.10.0.6/32: path 20.1.1.6 is the initial bestpath
2020/03/16 19:17:22.572435 BGP: bgp_best_selection: pi 0x5627187c66c0 dmed
2020/03/16 19:17:22.572441 BGP: 20.10.0.6/32: After path selection, newbest is path 20.1.1.6 oldbest was NONE
2020/03/16 19:17:22.572447 BGP: 20.10.0.6/32: path 20.1.1.6 is the bestpath, add to the multipath list
2020/03/16 19:17:22.572453 BGP: 20.10.0.6/32: path 2001:20:1:1::6 has the same nexthop as the bestpath, skip it
2020/03/16 19:17:22.572460 BGP: 20.10.0.6/32: starting mpath update, newbest 20.1.1.6 num candidates 1 old-mpath-count 0 old-cum-bw u0
2020/03/16 19:17:22.572466 BGP: 20.10.0.6/32: comparing candidate 20.1.1.6 with existing mpath NONE
2020/03/16 19:17:22.572473 BGP: 20.10.0.6/32: New mpath count (incl newbest) 1 mpath-change NO all_paths_lb 0 cum_bw u0
Effectively if BGP receives 2 paths it could end up running bgp_path_info_cmp multiple times
and in some situations overwrite the reason selected the first time through.
In this example path selection is run and the MED is the reason for the choice.
Then in bgp_best_selection is run again this time clearing new_select
to NULL before calling path selection for the first time. This second
call into path selection resets the reason, since it is only passing in one
path. So save the last reason selected and restore in this case.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
This scenario has been seen against microtik virtual machine with
bfd enabled. When remote microtik bgp reestablishes the bgp session
after a bgp reset, the bgp establishment comes first, then bfd is
initialising.
The second point is true for microtik, but not for frrouting, as the
frrouting, when receiving bfd down messages, is not at init state.
Actually, bfd state is up, and sees the first bfd down packet from
bfd as an issue. Consequently, the BGP session is cleared.
The fix consists in resetting the BFD session, only if bfd status is
considered as up, once BGP comes up.
That permits to align state machines of both local and remote bfd.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
When bgp is updated with local source, the bgp session is reset; bfd
also must be reset. The bgp_stop() handler handles all kind of
unexpected failures, so the placeholder to deregister from bfd should be
ok, providing that when bgp establishes, a similar function in bgp will
recreate bfd context.
Note that the bfd session is not reset on one specific case, where BFD
down event is the last reset. In that case, we must let BFD to monitor
the link.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
If the default BGP instance is importing routes from another instance and
the latter has a router-id update, the update handler needs to handle the
default instance in a special way.
Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by: Chirag Shah <chirag@cumulusnetworks.com>
Reviewed-by: Don Slice <dslice@cumulusnetworks.com>
Ticket: CM-26007
Reviewed By: CCR-9108
Testing Done: Detailed verification in 3.x
Ensure that the late registration for NHT done for IPv4 route exchange
over IPv6 GUA peering is not attempted for peer-groups, only for peers.
Fixes: "bgpd: Late registration of Extended Nexthop"
Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by: Donald Sharp <sharpd@cumulusnetworks.com>
This scenario has been seen against microtik virtual machine with bfd
enabled. When remote microtik bgp reestablishes the bgp session after a
bgp reset, the bgp establishment comes first, then bfd is initialising.
The second point is true for microtik, but not for frrouting, as the
frrouting, when receiving bfd down messages, is not at init state.
Actually, bfd state is up, and sees the first bfd down packet from bfd
as an issue. Consequently, the BGP session is cleared.
The fix consists in resetting the BFD session, once BGP comes up. That
permits to align state machines of both local and remote bfd.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
When bgp is updated with local source, the bgp session is reset; bfd
also must be reset. The bgp_stop() handler handles all kind of
unexpected failures, so the placeholder to deregister from bfd should be
ok, providing that when bgp establishes, a similar function in bgp will
recreate bfd context.
Note that the bfd session is not reset on one specific case, where BFD
down event is the last reset. In that case, we must let BFD to monitor
the link.
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
This fixes a linking issue on Fedora Rawhide:
/usr/bin/ld: bgpd/libbgp.a(bgp_flowspec.o):/home/ruben/src/frr/./bgpd/bgp_attr_evpn.h:37: multiple definition of `eth_tag_id'; bgpd/bgp_btoa-bgp_btoa.o:/home/ruben/src/frr/./bgpd/bgp_attr_evpn.h:37: first defined here
collect2: error: ld returned 1 exit status
Signed-off-by: Ruben Kerkhof <ruben@rubenkerkhof.com>
We were using XMALLOC for these, and only initializing the refcount to 0
on one of them. Let's just use XCALLOC instead...
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
