April 2018 - Bird-users - Mailing Lists

BGP route selection
by Arvin Gan 27 Apr '18

27 Apr '18

Hi, I notice that there is a description of route selection algorithm: The global best route selection algorithm is (roughly) as follows: * Preferences of the routes are compared. * Source protocol instance preferences are compared. * If source protocols are the same (e.g. BGP vs. BGP), the protocol's route selection algorithm is invoked. * If source protocols are different (e.g. BGP vs. OSPF), result of the algorithm is undefined. And I also notice that normally the configuration "Administrative Distance" that is mapped to preference under channel in bird is different between eBGP (default value 20) and iBGP (default value 200). My question is : If iBgp preference is lower than eBGP preference that mean iBGP priority higher than eBGP, iBGP route is selected or eBGP route is selected, do anyone know it? But in BGP instance, eGBP is prior than iBGP.... Appreciated in advance! Thanks Arvin

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Community range to match on import filter.
by Osmos City 26 Apr '18

26 Apr '18

Hi there, just wondering how to migrate to Bird configuration this entry from another RR: “regex 65000:50[0-9][0-9]” applied to a BGP import route-map on community match. Tried on Bird: “if ([(65000,5000..5099)]) ~ bgp_community then “action" After that, no prefixes have been imported with those communities. Any idea if it should work or I’ve missed something? Thanks in advance. Regards, Jorge.

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netlink support question for RFC 5549
by Arvin Gan 26 Apr '18

26 Apr '18

Hi All, I notice that BGP can support RFC 5549 using configuration "ext_next_hop", bird can sync with kernel table using netlink assuming kernel support route with IPV4 DIP and IPV6 next hop. Sending route to kernel (nl_add_nexthop()) that don't check address family type that mean bird can send IPV4 NLRI with IPV6 next_hop to kernel if enabled "ext_next_hop". For bird receiving kernel route table, bird parse the gateway with nl_parse_attrs from rtm_attr_want4/rtm_attr_want6 based on address family , that mean if bird received IPV4 NLRI with IPV6 next hop, the gateway is parsed with IPV4 address since address family is IPV4 unicast on this case, does my understand correct ? If yes, this parse process have a bug ? Thanks Arvin

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MP-BGP announcements
by Jan-Philipp Litza 25 Apr '18

25 Apr '18

Hi list, I'm currently implementing a BGP setup with bird 2.0 and was wondering whether it is possible to disable announcing IPv6 support to IPv4 peers: Local capabilities Multiprotocol AF announced: ipv4 ipv6 There is no IPv6 channel configured for the protocol. Also, the situation with IPv6 is as expected: It only announces IPv6 support: Local capabilities Multiprotocol AF announced: ipv6 Any hints? Best regards, Jan-Philipp Litza -- Jan-Philipp Litza PLUTEX GmbH Hermann-Ritter-Str. 108 28197 Bremen Hotline: 0800 100 400 800 Telefon: 0800 100 400 821 Telefax: 0800 100 400 888 E-Mail: support(a)plutex.de Internet: http://www.plutex.de USt-IdNr.: DE 815030856 Handelsregister: Amtsgericht Bremen, HRB 25144 Geschäftsführer: Torben Belz, Hendrik Lilienthal

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Linux routing
by knet solutions 24 Apr '18

24 Apr '18

All, I am facing a strange issue (all routers are linux with bird runnning). My topology(RING Topology) is as below, R1 ------------R2------------R3---------R4 BGP is running on all nodes. R1 to R3 route is going via R1--R2--R3 and the return path is in also in same path (R3--R2----R1), then thing works fine But suppose, R1 to R3 path is R1---R2---R3 and return path is R3----R4---R1. then traffic is not passing. Any configurations i should do in linux ? -- *Regards, * *Suresh* *Knet solutions.* https://github.com/knetsolutions/KNet http://knet-topology-builder.readthedocs.io/ http://knetsolutions.in/

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Debugging bird 1.6.3
by Manel Pérez 24 Apr '18

24 Apr '18

Hi all, I've a problem with a function in bird and I would like to do print for see what it happens (bold). How can i see this prints in the log? log "/var/log/bird.log" all; debug protocols { states, routes, filters, interfaces, events }; ******************************************** # AS1111, used_by client AS1111_1 Client define AS_SET_AS1111_asns = [ 1111 ]; define AS_SET_AS1111_prefixes = [ 1.1.1.1/24 ]; AS-SET for AS1111_1 function origin_as_is_in_AS1111_1_as_set() { if bgp_path.last ~ AS_SET_AS1111_asns then return true; return false; } # R-SET for AS1111_1 function prefix_is_in_AS1111_1_as_set() { if net ~ AS_SET_AS1111_prefixes then return true; return false; } function verify_AS1111_1_irrdb() bool origin_ok; bool prefix_ok; bool validated; { origin_ok = false; prefix_ok = false; validated = false; origin_ok = origin_as_is_in_AS1111_1_as_set(); prefix_ok = prefix_is_in_AS1111_1_as_set(); * print origin_ok;** ** print prefix_ok;* if !origin_ok then { bgp_community.add((65530, 0)); bgp_large_community.add((RSasn, 65530, 0)); } if origin_ok then { bgp_community.add((65530, 1)); bgp_large_community.add((RSasn, 65530, 1)); } if !validated && !origin_ok then { reject "origin ASN [", bgp_path.last, "] not in allowed as-sets - REJECTING ", net; } if !validated && !prefix_ok then { reject "prefix not in client's r_set - REJECTING ", net; } } filter receive_from_AS1111_1{ ....... verify_AS1111_1_irrdb() ....... } ******************************************* Thank you in advance. Manel

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Apply new next-hop
by Titov Stas 24 Apr '18

24 Apr '18

Hello, I have some difficulties with change IPv6 next-hop. I've got ipv6 prefixes in ISP_ISP2 table from rr bgp peer: bird> show route table ISP_ISP2 2a01:230:2:41::a16/128 unreachable [bgp2 2018-04-17 from 2a01:230:3:1::3] * (101/-) [i] 2a01:230:2:41::a17/128 unreachable [bgp2 2018-04-17 from 2a01:230:3:1::3] * (101/-) [i] ... and export in kernel table 11 [root@nvkvm-3 ~]# ip -6 route show table 11 | more unreachable 2a01:230:2:41::2 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::3 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::4 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::6 dev lo proto bird metric 1024 error -113 How I can make their reachable via my gw: 2a01:230:2:53::9? I tried export filter nh_in; filter nh_in { if ( net ~ [ 2a01:230:2:41::/64+ ] ) then { gw = 2a01:230:2:53::9; accept; } } but it make not help me. Can you advise?

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BIRD 2.0.2 and 1.6.4
by Ondrej Filip 23 Apr '18

23 Apr '18

Dear BIRD users, we just released two new versions - 1.6.4 and 2.0.2. There is an important security bugfix in both. Upgrade is highly recommended. Version 2.0.2 (2018-03-22) o Source-specific routing support for Linux kernel and Babel o BGP: New option 'disable after cease' o Filter: Allow silent filter execution o Filter: Fixed stack overflow in BGP mask expressions. o Several bugfixes Notes: Syntax prefix:netmask for IPv4 prefixes was dropped. Just use prefix/pxlen. Version 1.6.4 (2018-03-22) o Basic VRF support o Simplified autoconf scripts o BGP: Shutdown communication (RFC 8203) o BGP: Allow exchanging LOCAL_PREF with eBGP peers o BGP: Allow to specify interface for regular sessions o BGP: New option 'disable after cease' o RAdv: Support for more specific routes (RFC 4191) o RAdv: Proper handling of prefix retraction o Filter: Allow silent filter execution o Filter: Fixed stack overflow in BGP mask expressions. o Several bug fixes Ondrej

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OSPFv3 using Link-Local instead of Global
by Stefan Schultheis (home) 22 Apr '18

22 Apr '18

Hi, it's not a problem as everything works, but I see that OSPFv3 does adjecencies via Link-Local addresses (fe80) instead of global routed ones: $ birdc6 show ospf neigh BIRD 1.6.3 ready. ospf1: Router ID Pri State DTime Interface Router IP 78.xxx.yyy.37 1 Full/PtP 00:17 enp1s0.503 fe80::202:c9ff:fe52:2776 78.xxx.yyy.36 1 Full/PtP 00:19 enp1s0.508 fe80::202:c9ff:fe10:f084 Also, routing in Kernel is using link local address: $ netstat -nr -A inet6 | grep 2a00:11c0 2a00:11c0:47:3::2a/127 fe80::202:c9ff:fe52:2776 UG 1024 2 50 enp1s0.503 Does anyone have a hint on how to easily make it use the global scope IPs instead of Link Local? I don't want to explicitely name IPs in the config if this can be avoided... The config file is as simple as can be: protocol ospf { import all; export all; area 0 { interface "lo" { cost 5; hello 5; retransmit 2; wait 10; dead 20; }; interface "enp1s0.503" { cost 5; type pointopoint; hello 5; retransmit 2; wait 10; dead 20; }; interface "enp1s0.508" { cost 1000; type pointopoint; hello 5; retransmit 2; wait 10; dead 20; }; }; } Thank you! LgS

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How to set another next-hop
by Titov Stas 20 Apr '18

20 Apr '18

Guys, I have some troble with change next-hop. I've got ipv6 prefixes in ISP_ISP2 table from rr bgp peer: bird> show route table ISP_ISP2 2a01:230:2:41::a16/128 unreachable [bgp2 2018-04-17 from 2a01:230:3:1::3] * (101/-) [i] 2a01:230:2:41::a17/128 unreachable [bgp2 2018-04-17 from 2a01:230:3:1::3] * (101/-) [i] ... and export in kernel table 11 [root@nvkvm-3 ~]# ip -6 route show table 11 | more unreachable 2a01:230:2:41::2 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::3 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::4 dev lo proto bird metric 1024 error -113 unreachable 2a01:230:2:41::6 dev lo proto bird metric 1024 error -113 How I can make their reachable via my gw: 2a01:230:2:53::9? I tried export filter nh_in; filter nh_in { if ( net ~ [ 2a01:230:2:41::/64+ ] ) then { gw = 2a01:230:2:53::9; accept; } } but it make not help me.

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