Refreshement of BGP multi ASNs #16838
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1. bgp coredump is observed when we delete default bgp instance when we have multi-vrf; and route-leaking is enabled between default, non-default vrfs. Removing default router bgp when routes leaked between non-default vrfs. - Routes are leaked from VRF-A to VRF-B - VPN table is created with auto RD/RT in default instance. - Default instance is deleted, we try to unimport the routes from all VRFs - non-default VRF schedules a work-queue to process deleted routes. - Meanwhile default bgp instance clears VPN tables and free the route entries as well, which are still referenced by non-default VRFs which have imported routes. - When work queue process starts to delete imported route in VRF-A it cores as it accesses freed memory. - Whenever we delete bgp in default vrf, we skip deleting routes in the vpn table, import and export lists. - The default hidden bgp instance will not be listed in any of the show commands. - Whenever we create new default instance, handle it with AS number change i.e. old hidden default bgp's AS number is updated and also changing local_as for all peers. 2. A default instance is created with ASN of the vrf with the import statement. This may not be the ASN desired for the default table - First problem with current behavior. Define two vrfs with different ASNs and then add import between. starting without any bgp config (no default instance) A default instance is created with ASN of the vrf with the import statement. This may not be the ASN desired for the default table - Second related problem. Start with a default instance and a vrf in a different ASN. Do an import statement in the vrf for a bgp vrf instance not yet defined and it auto-creates that bgp/vrf instance and it inherits the ASN of the importing vrf - Handle bgp instances with different ASNs and handle ASN for auto created BGP instance Signed-off-by: Kantesh Mundaragi <[email protected]>
While it's okay to allow overwriting the ASN of a bgp vrf/instance that is either hidden or automatically created, it's dangerous to allow it on explicitly defined instances. If that were allowed, a typo entering the bgp config could take down existing peering, which would be a bad thing. Signed-off-by: Don Slice <[email protected]>
When we leak routes and are using a different ASN in the source vrf from the target vrf, it's possible we could create loops because of an incomplete as-path (missing the source vrf ASN). This fix adds the source vrf ASN and stops the importing of a BGP prefix that has the target ASN in the as-path in the source vrf. Signed-off-by: Don Slice <[email protected]>
When a prefix in a vrf is imported into evpn as a type5, copy the asn of the source to make sure it is reflected in the target vrf. Ticket: cumuluslinux-2554562 Signed-off-by: Don Slice <[email protected]>
When we get a update on a route that we already have information on from another router and that route has been leaked ensure that we do not crash when trying to releak the code when we may want to modify the as path. Signed-off-by: Donald Sharp <[email protected]>
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```
==5445==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x7ff4c6bedb19 bp 0x7ffc95f2e400 sp 0x7ffc95f2e3c0 T0)
==5445==The signal is caused by a READ memory access.
==5445==Hint: address points to the zero page.
#0 0x7ff4c6bedb19 in hash_iterate lib/hash.c:246
#1 0x5618f41f5f59 in bgp_evpn_nh_finish bgpd/bgp_evpn_mh.c:4663
#2 0x5618f41dcbe8 in bgp_evpn_vrf_delete bgpd/bgp_evpn.c:7336
#3 0x5618f43bdd35 in bgp_delete bgpd/bgpd.c:4098
#4 0x5618f417ef6e in bgp_exit bgpd/bgp_main.c:206
#5 0x5618f417ef6e in sigint bgpd/bgp_main.c:164
#6 0x7ff4c6cac6c4 in frr_sigevent_process lib/sigevent.c:117
#7 0x7ff4c6cd8258 in event_fetch lib/event.c:1767
#8 0x7ff4c6c0dcbc in frr_run lib/libfrr.c:1230
#9 0x5618f418080d in main bgpd/bgp_main.c:555
#10 0x7ff4c670c249 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#11 0x7ff4c670c304 in __libc_start_main_impl ../csu/libc-start.c:360
#12 0x5618f417ea20 in _start (/usr/lib/frr/bgpd+0x2e4a20)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV lib/hash.c:246 in hash_iterate
```
Signed-off-by: Donatas Abraitis <[email protected]>
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#9079