October 2017 - Bird-users

Adding more then one bgp community at once
by Борис Коваленко 05 May '23

05 May '23

Hello! Is this possible to add many communites at once? bgp_community.add([(1,1), (1,2)]) is wrong "Setting clist attribute to non-clist value" Regards, Boris -- С уважением, Борис Коваленко

4 5

manipulating the best path, eBGP, MED?
by Thomas＠PhaseHosting 14 Apr '18

14 Apr '18

Supp, I implemented bird in our Private cloud running proxmox to distribute our public address with eBGP to our serverhost. Through iBGP and a ucarp interface i have a HA gateway, the problem is that our host receives the routes but there are multiple entry points to our subnet ( the proxmox hosts). This makes that a diffrent in & out route doenst work. through following link: https://supportforums.cisco.com/document/126691/understanding-bgp-best-path… I learned that my hosts selects its route based on age ( the bird with the first connection is chosen). Can i send a multi-exit discriminator with my eBGP connection to my host? I googled but could find 2 answers that did't change anything: # your default gateway IP below here protocol bgp eBGP { import none; export where proto = "static_packet"; local as 65000; neighbor 10.80.x.x as 65530; password "SECRET"; #med metric 10; #default bgp_med 10; } (offcourse i tried both without # and waited till export) Or is there an other way to make sure that our host routes always to the first server and so on. -- Thomas Valgaeren thomas(a)phasehosting.io +32477915307

6 8

Re: Decode BGP Shutdown Communication messages (RFC 8203)
by Mikhail Grishin 15 Nov '17

15 Nov '17

Hi, 1) You also implemented enable bgp2 "enable message" This message currently seen only at local side and doesn't seen at remote peer. Scenario: You made maintenance work with the shutdown message "Session will be down from 13:00 till 14:00". Later session was established again. Days after at remote peer side still printed the same message. That's confusing. Suggestion: (May be) To show two different messages? Tx and Rx. To clear Rx message every time when BGP session state changed to established. 2) Is it possible to log such messages and see via syslog? P.S. For russian UTF8 text 128 bytes restriction (RFC) probably not always enough. Ondrej Zajicek пишет 19.09.2017 21:53: > On Thu, Jul 27, 2017 at 05:55:40PM +0200, Job Snijders wrote: >> Hi all, >> >> Here is a patch to decode received BGP shutdown communication messages >> as specified in RFC 8203. In the following example scenario I'm sending >> a shutdown communication with openbgpd: >> >> $ bgpctl neighbor 94.142.241.204 down "TICKET-2331 we are upgrading, back in 30 min" >> request processed > Hi > > Merged with some significant changes, with support for both RX and TX of > shutdown communication: > > https://gitlab.labs.nic.cz/labs/bird/commit/cd1d99611e445c9fe2452d05627ccfc… > > I generalized it a bit, so the message is not specific to BGP, but can be > attached to any protocol, so it makes sense that it can be changed by > general commands like disable, restart. That means it also changed the > output a bit: > > bird> show protocols all bgp2 > name proto table state since info > bgp2 BGP master down 19:39:00 > Description: My BGP session > Message: Planned shutdown, back in 30 min > Preference: 100 > Input filter: ACCEPT > Output filter: (unnamed) > BGP state: Down > Neighbor address: 10.0.1.1 > Neighbor AS: 10 > > Conceptually, it is one-item mailbox, which can be set by either the core > (using enable/disable/restart commands) or the protocol (received BGP > Notification with the RFC 8203 message). I am not sure if it would not be > better to have two separate mailboxes for both directions, but it > probably does not matter. > > The message can be send from BIRD shell: > > birdc> disable bgp1 "hi, we will upgrade to bird 1.6.4" > > Unfortunately, that means that from Unix shell you have to do double qouting: > > birdc disable bgp1 '"hi, we will upgrade to bird 1.6.4"' > > Currently no support for message associated with 'disabled' in bird.conf > or for message associated with BIRD global shutdown. > > > Otherwise, there are some minor changes w.r.t. your patch: > > 1) Your patch requires that RFC 8203 message fills the entire space of > BGP notification (i.e. msg_len + 1 == remaining_len). I do not see any > such requirement in RFC 8203, so i accept if (msg_len + 1 <= remaining_len) > > 2) I reset the message not with any RX notification, but only with > administrative shutdown/reset notification. That prevents message reset > with subsequent errors unrelated to administrative notification. > > 3) Proper handling of zero-length messages (should be handled equally > like no message at all according to RFC 8203). > > 4) Some basic sanitization of received strings to avoid escape-attacks > and newlines in logs. > > Any comments, suggestions, opposition? >

3 4

[PATCH] babel: Ignore Hello TLVs with unicast flag set
by Toke Høiland-Jørgensen 31 Oct '17

31 Oct '17

RFC6126bis introduces a flags field for the Hello TLV, and adds a unicast flag that is used to signify that a hello was sent as unicast. This adds parsing of the flags field and ignores such unicast hellos, which preserves compatibility until we can add a proper implementation of the unicast hello mechanism. Signed-off-by: Toke Høiland-Jørgensen <toke(a)toke.dk> --- proto/babel/packets.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/proto/babel/packets.c b/proto/babel/packets.c index efe05678..597ed60d 100644 --- a/proto/babel/packets.c +++ b/proto/babel/packets.c @@ -40,7 +40,7 @@ struct babel_tlv_ack { struct babel_tlv_hello { u8 type; u8 length; - u16 reserved; + u16 flags; u16 seqno; u16 interval; } PACKED; @@ -104,8 +104,9 @@ struct babel_tlv_seqno_request { } PACKED; -#define BABEL_FLAG_DEF_PREFIX 0x80 -#define BABEL_FLAG_ROUTER_ID 0x40 +#define BABEL_FLAG_DEF_PREFIX 0x80 +#define BABEL_FLAG_ROUTER_ID 0x40 +#define BABEL_FLAG_UNICAST_HELLO 0x8000 struct babel_parse_state { @@ -340,6 +341,12 @@ babel_read_hello(struct babel_tlv *hdr, union babel_msg *m, { struct babel_tlv_hello *tlv = (void *) hdr; struct babel_msg_hello *msg = &m->hello; + u16 flags; + + /* We currently don't support unicast Hello */ + flags = get_u16(&tlv->flags); + if (flags & BABEL_FLAG_UNICAST_HELLO) + return PARSE_IGNORE; msg->type = BABEL_TLV_HELLO; msg->seqno = get_u16(&tlv->seqno); -- 2.14.2

2 2

RE: Bird redundant routers with same AS on same location and prefix delegation to lower router
by Gelderman, Richard 26 Oct '17

26 Oct '17

Hi Andrew, As I am new to Bird I can not find a good example how to create a RR cluster with two routers R1 + R2. Do you have experience with a RR cluster with multiple routers? My biggest question is acquily how to config the sessions between R1 + R2 as clustermembers without creating a loop. Regards, Richard Van: Andrew [mailto:nitr0@seti.kr.ua] Verzonden: donderdag 7 september 2017 16:55 Aan: Gelderman, Richard <r.gelderman(a)rtvoost.nl> Onderwerp: Re: Bird redundant routers with same AS on same location and prefix delegation to lower router You may redistribute all routes between R1 and R2 using RR (both received from R3 and received from uplinks), and redistribute just default to R3 using separate table (with static default and routes peering to main table). On 07.09.2017 17:38, Gelderman, Richard wrote: Hi Adrew, I thought about this option, I don't want to pass a full BGP table towards R3. In other words R1 + R2 should be used for routing for all routes and R3 should only route net A and net B and must route through to reach other networks. Regards, Richard Van: Bird-users [mailto:bird-users-bounces@network.cz] Namens Andrew Verzonden: donderdag 7 september 2017 15:06 Aan: bird-users(a)network.cz<mailto:bird-users@network.cz> Onderwerp: Re: Bird redundant routers with same AS on same location and prefix delegation to lower router Hi. You should configure R1 and R2 as route reflectors. On 07.09.2017 14:17, Gelderman, Richard wrote: I am trying to achieve a redundant routing setup with two routers with the same ASN who do prefix delegation to a lower router. The setup is the following: AS1000 ISP1 ISP2 AS2000 | | | | AS10000 R1 ======== R2 AS10000 prefix /22 \ iBGP / prefix /22 \ / \ / \ / R3 AS65000 / \ / \ net A net B prefix /24 prefix /24 Does anybody has experience with this kind of setup? Regards, Richard

4 4

Dynamic add BGP config
by Magnus Löfqvist 20 Oct '17

20 Oct '17

Hi, It is possible to dynamic add BGP neighbors to the config when a "unknown" tries to estsblish a BGP session? We have a iBGP RR that we connect routers connected to a transport network. It should be nice that we dont need to change the configuration at the RR when we add a new router. To day I have predefined passive neighbors, but maybe it are some better way of doing this? / Magnus Sent from Nine<http://www.9folders.com/>

1 0

conf ch -> kill bird
by Mikhail Mayorov 20 Oct '17

20 Oct '17

bird ~ # birdc BIRD 1.6.3 ready. bird> configure check Reading configuration from /usr/local/etc/bird/bird.conf Configuration OK bird> configure Connection closed by server Can't catch an error in a configuration file. In testing, everything OK. But when you apply all the bad and the bird just falls. In log file I got: Oct 20 17:10:42 bird bird[19609]: Reconfiguring Oct 20 17:10:42 bird bird[19609]: Unknown instruction 8574 in same (~) After start I got: Oct 20 17:10:44 bird bird[19675]: Graceful restart started Oct 20 17:10:44 bird bird[19675]: Started Oct 20 17:10:44 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:44 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:44 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:44 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:44 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:44 bird bird[19675]: ... Oct 20 17:10:56 bird bird[19675]: I/O loop cycle took 11494 ms for 13 events Oct 20 17:10:56 bird bird[19675]: Kernel dropped some netlink messages, will resync on next scan. Oct 20 17:10:56 bird bird[19675]: papa_ipv4: Received: Cease Oct 20 17:10:56 bird bird[19675]: Kernel dropped some netlink messages, will resync on next scan. Oct 20 17:10:56 bird bird[19675]: blockhole_rfc7999_ipv4_bgpin: set RTD_BLACKHOLE for 194.85.16.6/32 from 193.232.140.100 Oct 20 17:10:58 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:58 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:58 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:58 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:58 bird bird[19675]: filters, line 11: ~ applied on unknown type pair Oct 20 17:10:59 bird bird[19675]: ... Oct 20 17:10:59 bird bird[19675]: Kernel dropped some netlink messages, will resync on next scan. I suspect that the error in the file bird-all.functions function tier1. My configuration: BIRD.rndbird bird # cat bird.conf include "bird-all.conf"; include "bird-ipv4.functions"; include "bird-roa4.conf"; [skip] BIRD.rndbird bird # cat bird-all.functions function clear_my_comm() pair set my_comm; { my_comm = [ (49037, *) ]; bgp_community = delete( bgp_community, my_comm ); } function tier1(bgppath cp) { if cp ~ [= * 1 * =] then return true; # Level 3 Communications if cp ~ [= * 209 * =] then return true; # CenturyLink if cp ~ [= * 286 * =] then return true; # KPN International if cp ~ [= * 701 * =] then return true; # Verizon Enterprise Solutions if cp ~ [= * 702 * =] then return true; # Verizon Enterprise Solutions if cp ~ [= * 703 * =] then return true; # Verizon Enterprise Solutions if cp ~ [= * 1239 * =] then return true; # Sprint if cp ~ [= * 1299 * =] then return true; # Telia Carrier if cp ~ [= * 2828 * =] then return true; # Verizon Enterprise Solutions if cp ~ [= * 2914 * =] then return true; # NTT Communications if cp ~ [= * 3257 * =] then return true; # Global Telecom & Technology (GTT) if cp ~ [= * 3320 * =] then return true; # Deutsche Telekom AG (ICSS) if cp ~ [= * 3356 * =] then return true; # Level 3 Communications if cp ~ [= * 3549 * =] then return true; # Level 3 Communications if cp ~ [= * 3561 * =] then return true; # CenturyLink if cp ~ [= * 4436 * =] then return true; # Global Telecom & Technology (GTT) if cp ~ [= * 5511 * =] then return true; # Orange if cp ~ [= * 6453 * =] then return true; # Tata Communications (INDIA) if cp ~ [= * 6461 * =] then return true; # Zayo Group if cp ~ [= * 6762 * =] then return true; # Telecom Italia Sparkle (Seabone) if cp ~ [= * 6830 * =] then return true; # Liberty Global if cp ~ [= * 7018 * =] then return true; # AT&T if cp ~ [= * 12956 * =] then return true; # Telefonica Global Solutions return false; } function aggroute() { if tier1(bgp_path) then return true; return false; } -- Regards, Mikhail V. Majorov Megalink Company, Director of engineering 318, Chehova street, Taganrog, Russia, 347932 tel work: +7 8634 431431 (ext 101) tel mobile: +7 918 5565520 sip: 000101(a)tagan.ru www.tagan.ru

2 2

bgp announce default route to lower router, what is the bird version of default-originate / default-information orginate?
by Gelderman, Richard 20 Oct '17

20 Oct '17

How can I announce a default route to a lower router who does not need a full table. What is de Bird equivalent of "default-orginitate" or "default-information originate". Currently I use a filter with a static blackhole route: protocol static { route 0.0.0.0/0 blackhole; } filter senddefault { if net = 0.0.0.0/0 then accept; reject; } template bgp local_as_ibgp_lowrouter { # export filter senddefault; }

3 2

Issues in Babel
by Ondrej Zajicek 19 Oct '17

19 Oct '17

Hi Toke (and others) I updated Babel to use microsecond timers [1] and during testing i noticed several unrelated issues. 1) Hello expiration was not properly implemented, as i understand RFC, it should reset the timer based on last packet hello interval and time-out repeatedly until hello map is zero. Fixed in [2]. 2) In some setups unicast seqno requests were sent repeatedly and seqno was increased indefinitely due to last case in babel_handle_update(), when the RFC specifies it should be done only if unfeasible route would otherwise become best. Fixed in [3], by this condition handling all unicast seqno requests: if (!feasible && (metric != BABEL_INFINITY) && (!best || (r == best) || (metric < best->metric))) babel_unicast_seqno_request(e, s, nbr); It also changes the behavior by sending seqno request when receiving infeasible update if there is no previous route from that neighbor. 3) Seems like the fix of hello expiration caused that when neighbor disappears, it is no longer removed timely and routes have to wait for route timeout, which is about a minute for 4 s hello interval. It seems that by RFC, we should recompute route metrics whanever rxcost reported by IHU is changed, so IHU expiration should be enough to make all related routes unreachable. Apparently, this is not done in BIRD. 4) Seems like we do not trigger updates when a route update with just increased seqno due to forwarded unicast request is received. That also slows convergence. IMHO we should do in babel_handle_update() something like: if (route_is_selected() && matching_entry_in_seqno_request_cache()) babel_trigger_update() Do you think that my interpretation of these issues and the fixes are correct? [1] https://gitlab.labs.nic.cz/labs/bird/commit/8a76785a6fb23a64fcc93f998336794… [2] https://gitlab.labs.nic.cz/labs/bird/commit/c7fa4efd701716a9c40620f2e3e8f06… [3] https://gitlab.labs.nic.cz/labs/bird/commit/c54526afeb4187d55993c3ab777fcfe… -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago(a)crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."

2 3

Limit on how many neighbors
by Magnus Löfqvist 15 Oct '17

15 Oct '17

Hi, We are running Bird with OSPF between embedded routers (openwrt) (mobile routers). The routers are connected to our main server with openvpn, and we are using bird ontop on openvpn to deliver routes to the end routers. This have worked quite well, but today we notice some glitches. We had some routers that did not finish election (ie, stand in init instead of being full). When we count, there are exactly 100 devices that are in "full", and 3 in init. Are there any limit on how many neighbors/routers? Med vänlig hälsning / Best regards Magnus Löfqvist

4 6