RE: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s)
To address the risk of somebody exhausting your memory by dumping a ton of routes on you, we added two new options to "soft-reconfiguration inbound" in IOS-XR. RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy. RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy. This was released in 7.3.1 in Feb 2021. The bug CSCwb17937 was fixed in 7.5.2, just released. Fixed a few other things in 7.5.2 also. Tomoya, apologies that you had a terrible time with it. Regards, Jakob. -----Original Message----- Date: Wed, 11 May 2022 14:31:28 -0700 From: Randy Bush <randy@psg.com> To: Pirawat WATANAPONGSE via NANOG <nanog@nanog.org> Subject: Re: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s) and upstream(s) Message-ID: <m2lev7kb7z.wl-randy@psg.com> Content-Type: text/plain; charset=US-ASCII
Is setting 'Soft Reconfiguration' enough for me to keep ROV running?
yes, should be.
If not, is there any other solution?
yes. jakob says he has implemented https://datatracker.ietf.org/doc/draft-ietf-sidrops-rov-no-rr/, though i do not known in what xr image(s) randy
On 5/12/22 23:40, Jakob Heitz (jheitz) via NANOG wrote:
To address the risk of somebody exhausting your memory by dumping a ton of routes on you, we added two new options to "soft-reconfiguration inbound" in IOS-XR.
RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy.
RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy.
This was released in 7.3.1 in Feb 2021.
The bug CSCwb17937 was fixed in 7.5.2, just released. Fixed a few other things in 7.5.2 also. Tomoya, apologies that you had a terrible time with it.
Awesome! Mark.
On Fri, 13 May 2022 at 00:44, Jakob Heitz (jheitz) via NANOG <nanog@nanog.org> wrote:
RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy.
RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy.
What does this mean? If any term refers to validation-state, the route gets stored? Eg. if validation-state is valid then pass else drop a) Would 'RPKI-dropped-only' store everything or nothing? b) Would 'RPKI-tested-only' store everything? -- ++ytti
'RPKI-tested-only' will store all routes that encounter a 'validation-state' test in the inbound route policy. In that case, when an RPKI server updates a VRP to the router, it can re-run the inbound policy from the stored route and not require a refresh request to be sent. This option saves memory if you use a coarse filter in the route-policy before the validation test. For example, you use a peer-locking filter to drop peer routes from your customers before they hit the validation-state test. Then a massive route leak won't chew up soft-reconfiguration memory. If a validation-state test drops a route and that route is not stored by soft-reconfiguration, then when the RPKI server updates any VRP, the router needs to send a route-refresh request. 'RPKI-dropped-only' causes the dropped routes to be stored. This will prevent the unnecessary route-refreshes described above. It does not prevent all route-refreshes, but uses significantly less memory than 'RPKI-tested-only' Regards, Jakob. -----Original Message----- From: Saku Ytti <saku@ytti.fi> Sent: Friday, May 13, 2022 12:36 AM To: Jakob Heitz (jheitz) <jheitz@cisco.com> Cc: nanog@nanog.org Subject: Re: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s) On Fri, 13 May 2022 at 00:44, Jakob Heitz (jheitz) via NANOG <nanog@nanog.org> wrote:
RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy.
RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy.
What does this mean? If any term refers to validation-state, the route gets stored? Eg. if validation-state is valid then pass else drop a) Would 'RPKI-dropped-only' store everything or nothing? b) Would 'RPKI-tested-only' store everything? -- ++ytti
On 5/13/22 23:16, Jakob Heitz (jheitz) via NANOG wrote:
'RPKI-tested-only' will store all routes that encounter a 'validation-state' test in the inbound route policy. In that case, when an RPKI server updates a VRP to the router, it can re-run the inbound policy from the stored route and not require a refresh request to be sent.
This option saves memory if you use a coarse filter in the route-policy before the validation test. For example, you use a peer-locking filter to drop peer routes from your customers before they hit the validation-state test. Then a massive route leak won't chew up soft-reconfiguration memory.
If a validation-state test drops a route and that route is not stored by soft-reconfiguration, then when the RPKI server updates any VRP, the router needs to send a route-refresh request.
'RPKI-dropped-only' causes the dropped routes to be stored. This will prevent the unnecessary route-refreshes described above. It does not prevent all route-refreshes, but uses significantly less memory than 'RPKI-tested-only'
Jakob, thank you and your team for quickly implementing this. It is most appreciated. I hope someone from the IOS XE team is working on it, too :-). Mark.
On Sat, 14 May 2022 at 00:17, Jakob Heitz (jheitz) <jheitz@cisco.com> wrote: Hey Jakob,
'RPKI-tested-only' will store all routes that encounter a 'validation-state' test in the inbound route policy. In that case, when an RPKI server updates a VRP to the router, it can re-run the inbound policy from the stored route and not require a refresh request to be sent.
'RPKI-dropped-only' causes the dropped routes to be stored. This will prevent the unnecessary route-refreshes described above. It does not prevent all route-refreshes, but uses significantly less memory than 'RPKI-tested-only'
I'm sorry, but I am unable to reason what these answers mean in context of question that was: --- if validation-state is valid then pass else drop ---- I am assuming a) RPKI-tested-only would be same normal, and keep every single route b) RPKI-dropped-only would not keep anything (but it also might keep everything and be same as a)) That is, in this specific scenario, as far as I understand, there is no effect on the optimisations. Just to clarify why this type of policy may not be insane. IOS-XR has a 300k prefix limit for prefix-set, this limit is regularly hit by low quality as-set. By low quality I mean almost all as-set expand to unnecessarily large prefix-set, because as-set tend to be 'add only', there is no incentive to remove, so they just grow over time and do not represent in a meaningful manner the set of prefixes neighbours might advertise. And if we abstract what we the operators are actually doing, no one is doing prefix filtering, what everyone does is build AS-tree, by starting recursion from some as-set. So this AS-tree is the source of truth, no prefixes at all, prefixes are almost incentidental. After we have this AS-tree, we flatten it and for each element we ask for a route object with that origin. And then send this list to routers. Understanding what we actually do here, offers a mechanism for config size reduction as well as a standardized way to programmatically deploy those prefix-lists, by (ab)using RTR for this. We can fill all gaps from IRR data that RPKI data leaves us, then send a complete set of DFZ origins to routers, this allows us to accept only valid prefixes. Further the as-graph we created and flattened we can implement per-neighbour, which is trivial size compared to prefix-set size. Now compiling those AS path filters are regexp may not be so cheap, but some NOS offer cheap way to implement such AS filtering at scale: https://www.juniper.net/documentation/us/en/software/junos/routing-policy/to... If we do this 100% complete RTR and AS-set filter per neighbor, then we actually have better routing security than we have in the most canonical way, because we are enforcing origin:prefix relation, which we are not enforcing when we dump larger and low quality prefix-sets to routers. This makes us much less vulnerable to the low quality as-set both in operational manner by not inflating config sizes and cause commits to fail and by improving routing security.
Regards, Jakob.
-----Original Message----- From: Saku Ytti <saku@ytti.fi> Sent: Friday, May 13, 2022 12:36 AM To: Jakob Heitz (jheitz) <jheitz@cisco.com> Cc: nanog@nanog.org Subject: Re: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s)
On Fri, 13 May 2022 at 00:44, Jakob Heitz (jheitz) via NANOG <nanog@nanog.org> wrote:
RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy.
RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy.
What does this mean? If any term refers to validation-state, the route gets stored?
Eg.
if validation-state is valid then pass else drop
a) Would 'RPKI-dropped-only' store everything or nothing? b) Would 'RPKI-tested-only' store everything?
-- ++ytti
-- ++ytti
Saku, You have two questions. I'll address the second one first. Beginning in IOS-XR 7.3.1, there is a new O(log n) scalable way to test for autonomous system numbers (ASN) in route-policy. ASNs can be grouped into an as-set as follows: as-set foo 64496, 64497 end-set ! route-policy bar if not as-path originates-from foo then drop endif pass end-policy The first question: If you use several tests in your route-policy and put the validation-state test last, then any route that gets dropped before the validation-state test is reached will not be saved with "soft-reconfiguration inbound RPKI-tested-only". For example: route-policy bar if not as-path originates-from foo then drop endif if validation-state is invalid then drop endif pass end-policy Regards, Jakob. -----Original Message----- From: Saku Ytti <saku@ytti.fi> Sent: Saturday, May 14, 2022 12:09 AM To: Jakob Heitz (jheitz) <jheitz@cisco.com> Cc: nanog@nanog.org Subject: Re: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s) On Sat, 14 May 2022 at 00:17, Jakob Heitz (jheitz) <jheitz@cisco.com> wrote: Hey Jakob,
'RPKI-tested-only' will store all routes that encounter a 'validation-state' test in the inbound route policy. In that case, when an RPKI server updates a VRP to the router, it can re-run the inbound policy from the stored route and not require a refresh request to be sent.
'RPKI-dropped-only' causes the dropped routes to be stored. This will prevent the unnecessary route-refreshes described above. It does not prevent all route-refreshes, but uses significantly less memory than 'RPKI-tested-only'
I'm sorry, but I am unable to reason what these answers mean in context of question that was: --- if validation-state is valid then pass else drop ---- I am assuming a) RPKI-tested-only would be same normal, and keep every single route b) RPKI-dropped-only would not keep anything (but it also might keep everything and be same as a)) That is, in this specific scenario, as far as I understand, there is no effect on the optimisations. Just to clarify why this type of policy may not be insane. IOS-XR has a 300k prefix limit for prefix-set, this limit is regularly hit by low quality as-set. By low quality I mean almost all as-set expand to unnecessarily large prefix-set, because as-set tend to be 'add only', there is no incentive to remove, so they just grow over time and do not represent in a meaningful manner the set of prefixes neighbours might advertise. And if we abstract what we the operators are actually doing, no one is doing prefix filtering, what everyone does is build AS-tree, by starting recursion from some as-set. So this AS-tree is the source of truth, no prefixes at all, prefixes are almost incentidental. After we have this AS-tree, we flatten it and for each element we ask for a route object with that origin. And then send this list to routers. Understanding what we actually do here, offers a mechanism for config size reduction as well as a standardized way to programmatically deploy those prefix-lists, by (ab)using RTR for this. We can fill all gaps from IRR data that RPKI data leaves us, then send a complete set of DFZ origins to routers, this allows us to accept only valid prefixes. Further the as-graph we created and flattened we can implement per-neighbour, which is trivial size compared to prefix-set size. Now compiling those AS path filters are regexp may not be so cheap, but some NOS offer cheap way to implement such AS filtering at scale: https://www.juniper.net/documentation/us/en/software/junos/routing-policy/to... If we do this 100% complete RTR and AS-set filter per neighbor, then we actually have better routing security than we have in the most canonical way, because we are enforcing origin:prefix relation, which we are not enforcing when we dump larger and low quality prefix-sets to routers. This makes us much less vulnerable to the low quality as-set both in operational manner by not inflating config sizes and cause commits to fail and by improving routing security.
Regards, Jakob.
-----Original Message----- From: Saku Ytti <saku@ytti.fi> Sent: Friday, May 13, 2022 12:36 AM To: Jakob Heitz (jheitz) <jheitz@cisco.com> Cc: nanog@nanog.org Subject: Re: Newbie x Cisco IOS-XR x ROV: BCP to not harassing peer(s)
On Fri, 13 May 2022 at 00:44, Jakob Heitz (jheitz) via NANOG <nanog@nanog.org> wrote:
RPKI-dropped-only Saves a copy of only the routes dropped by an RPKI validation-state test in neighbor-in route-policy.
RPKI-tested-only Saves a copy of only the routes tested in an RPKI validation-state test in neighbor-in route-policy.
What does this mean? If any term refers to validation-state, the route gets stored?
Eg.
if validation-state is valid then pass else drop
a) Would 'RPKI-dropped-only' store everything or nothing? b) Would 'RPKI-tested-only' store everything?
-- ++ytti
-- ++ytti
On 14/05/2022 00:16, Jakob Heitz (jheitz) via NANOG wrote:
'RPKI-dropped-only' causes the dropped routes to be stored. This will prevent the unnecessary route-refreshes described above. It does not prevent all route-refreshes, but uses significantly less memory than 'RPKI-tested-only'
Regards, Jakob.
In the end, the reason for all this RPKI-thingy is to prevent route spoofing by malicious actors. It sure would be nice if someone from the top 20: https://asrank.caida.org/ would be able to have an auto-updated site that showed all RPKI dropped from their end. This would complement https://bgpstream.crosswork.cisco.com/ for those of us who want to know who is trying to hijack our routes at the core. Regards, Hank
Hank Nussbacher wrote on 14/05/2022 19:15:
In the end, the reason for all this RPKI-thingy is to prevent route spoofing by malicious actors.
a malicious actor will spoof the origin AS. The aim of RPKI to help stop mis-origination of prefixes, and the root cause of most of this is accidental. Nick
15.05.22 00:19, Nick Hilliard пише:
a malicious actor will spoof the origin AS. The aim of RPKI to help stop mis-origination of prefixes, and the root cause of most of this is accidental.
To make a working hijack of the routed prefix (for sniffing traffic, DDoS or something similar), you have to announce a more specific prefix(es). It can be denied by RPKI. If you signed RPKI prefix is still unannounced - yes, somebody can hijack it by forging the origin ASN - that's quite easy.
On Tue, 24 May 2022 at 11:23, Max Tulyev <maxtul@netassist.ua> wrote:
To make a working hijack of the routed prefix (for sniffing traffic, DDoS or something similar), you have to announce a more specific prefix(es). It can be denied by RPKI.
If you signed RPKI prefix is still unannounced - yes, somebody can hijack it by forging the origin ASN - that's quite easy.
This axiomatically assumes first come, first serve, which is obviously not complete understanding of BGP best path algorithm. -- ++ytti
In the end, the reason for all this RPKI-thingy is to prevent route spoofing by malicious actors.
sigh. for my quarterly posting of the same many year old text To be clear, as people keep calling BGP security 'RPKI', RPKI The RPKI is an X.509 based hierarchy [RFC 6481] which is congruent with the internet IP address allocation administration, the IANA, RIRs, ISPs, ... It is just a database, but is the substrate on which the next two mechanisms are based. It is currently deployed in all five administrative regions. RPKI-based Origin Validation (ROV) RPKI-based Origin Validation [RFC 6811] uses some of the RPKI data to allow a router to verify that the autonomous system originating an IP address prefix is in fact authorized to do so. This is not crypto checked so can be violated. But it should prevent the vast majority of accidental 'hijackings' on the internet today, e.g. the famous Pakistani accidental announcement of YouTube's address space. RPKI-based origin validation is in shipping code from AlcaLu, Cisco, Juniper, and possibly others. BGPsec RPKI-based Path Validation, AKA BGPsec, a future technology still being designed [draft-ietf-sidr-bgpsec-overview], uses the full crypto information of the RPKI to make up for the embarrassing mistake that, like much of the internet BGP was designed with no thought to securing the BGP protocol itself from being gamed/violated. It allows a receiver of a BGP announcement to cryptographically validate that the autonomous systems through which the announcement passed were indeed those which the sender/forwarder at each hop intended. Sorry to drone on, but these three really need to be differentiated.
participants (7)
-
Hank Nussbacher -
Jakob Heitz (jheitz) -
Mark Tinka -
Max Tulyev -
Nick Hilliard -
Randy Bush -
Saku Ytti