- Bird-users - Mailing Lists

Setting ONLINK flag for arbitrary routes
by Toke Høiland-Jørgensen 29 Apr '18

29 Apr '18

Hi Is it possible to set the ONLINK flag for arbitrary routes? The use case is a common setup in mesh networks: All devices have a /32 assigned to the interface and advertise this as the nexthop for v4 routes. The routing protocol then installs all kernel routes as onlink, allowing routes to be installed even though the nexthop is not in the same subnet as the local link address. Is this possible to configure in Bird currently? -Toke

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Difference between loopback and dummy interfaces for use in Linux routing
by Wilhelm Schuster 28 Apr '18

28 Apr '18

Hi, I’m learning about IP-networking and am in the process of setting up a Linux router using bird. During my research I’ve come across the usage of loopback interfaces. I could gather that this is done, because Ethernet interfaces for example (in contrast to loopbacks) can go down making the addresses configured on them unavailable. In addition, the kernel accepts packets destined to loopbacks addresses on other interfaces making these addresses available on multiple interfaces and not just the loopback. On Linux I found both the lo(opback), and dummy interfaces recommended to achieve the behavior outlined above. What I’m struggling with is understanding the differences between both interface types (besides the obvious difference in packet processing) and when to use which. Searching this mailing list I’ve seen people use lo, on other sites dummy interfaces are recommended. From a quick test (assigning address to lo/dummy; pinging/receiving pings on the host) I wasn’t able to find a difference. When should I use which interface? Cheers, Wilhelm.

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BGP filter
by Arvin Gan 28 Apr '18

28 Apr '18

Hi All, I am implementing a function that send default route to BGP peer, and I am facing an issue about BGP filter, when I use "show route filter" in birdc, the filter result is correct; when I add this filter to config-file and start bird, the bird will occur coredump issue. Does anyone know the reason? Appreciated in advance. 1. bird>show route filter {if format(net) = "0.0.0.0/0" then accept;} //correct result /* show route filter {if net = "0.0.0.0/0" then accept;} // incorrect result */ 2. config-file: filter filter_bgp1{ if format(net) = "0.0.0.0/0" then accept; // "format(net) = ..." , bird coredump ??? /* if net = "0.0.0.0/0" then accept; // " net= ..." , not bird coredump*/ } protocol bgp bgp1 { ...... ipv4 { import all; export filter filter_bgp1; }; ........ } Thanks Arvin

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Incoming connection rejected
by Julien Sansonnens 27 Apr '18

27 Apr '18

Hello all, I'm having a hard time trying to peer with some router over GRE tunnel. I'm using bird 1.6.4 I have many GRE tunnels and BGP sessions is working fine on all of the them except one. Session is locked on "Idle" state. Here are my logs: 2018-04-25 15:22:00 <TRACE> carl: Waiting for fd00:1111::2 to become my neighbor 2018-04-25 15:22:02 <TRACE> carl: Incoming connection from fd00:1111::2 (port 32967) rejected 2018-04-25 15:22:06 <TRACE> carl: Incoming connection from fd00:1111::2 (port 53399) rejected 2018-04-25 15:22:10 <TRACE> carl: Incoming connection from fd00:1111::2 (port 50357) rejected 2018-04-25 15:22:14 <TRACE> carl: Incoming connection from fd00:1111::2 (port 53999) rejected 2018-04-25 15:22:18 <TRACE> carl: Incoming connection from fd00:1111::2 (port 36137) rejected 2018-04-25 15:22:23 <TRACE> carl: Incoming connection from fd00:1111::2 (port 59443) rejected I can ping6 f d00:1111::2 withou problem. Tunnel looks OK to me. No problem with firewall. BGP packets are exchanged through the tunnel: tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on peer-carl, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes 15:26:59.597762 IP6 fd00:1111::2.47991 > fd00:1111::1.bgp: Flags [S], seq 3532263744, win 28320, options [mss 1416,sackOK,TS val 1966373497 ecr 0,nop,wscale 5], length 0 15:26:59.597898 IP6 fd00:1111::1.bgp > fd00:1111::2.47991: Flags [S.], seq 2214438171, ack 3532263745, win 28320, options [mss 1416,nop,wscale 7], length 0 15:26:59.601269 IP6 fd00:1111::2.47991 > fd00:1111::1.bgp: Flags [.], ack 1, win 885, length 0 15:26:59.601442 IP6 fd00:1111::2.47991 > fd00:1111::1.bgp: Flags [P.], seq 1:48, ack 1, win 885, length 47: BGP 15:26:59.601467 IP6 fd00:1111::1.bgp > fd00:1111::2.47991: Flags [.], ack 48, win 222, length 0 15:26:59.602785 IP6 fd00:1111::1.bgp > fd00:1111::2.47991: Flags [R.], seq 1, ack 48, win 222, length 0 15:27:02.621914 IP6 fd00:1111::2.34513 > fd00:1111::1.bgp: Flags [S], seq 1485692031, win 28320, options [mss 1416,sackOK,TS val 1966374253 ecr 0,nop,wscale 5], length 0 15:27:02.622016 IP6 fd00:1111::1.bgp > fd00:1111::2.34513: Flags [S.], seq 3172792013, ack 1485692032, win 28320, options [mss 1416,nop,wscale 7], length 0 15:27:02.625695 IP6 fd00:1111::2.34513 > fd00:1111::1.bgp: Flags [.], ack 1, win 885, length 0 15:27:02.625726 IP6 fd00:1111::2.34513 > fd00:1111::1.bgp: Flags [P.], seq 1:48, ack 1, win 885, length 47: BGP 15:27:02.625736 IP6 fd00:1111::1.bgp > fd00:1111::2.34513: Flags [.], ack 48, win 222, length 0 15:27:02.626707 IP6 fd00:1111::1.bgp > fd00:1111::2.34513: Flags [R.], seq 1, ack 48, win 222, length 0 15:27:08.248676 IP6 fd00:1111::2.42773 > fd00:1111::1.bgp: Flags [S], seq 4186722687, win 28320, options [mss 1416,sackOK,TS val 1966375660 ecr 0,nop,wscale 5], length 0 15:27:08.248777 IP6 fd00:1111::1.bgp > fd00:1111::2.42773: Flags [S.], seq 4273937540, ack 4186722688, win 28320, options [mss 1416,nop,wscale 7], length 0 15:27:08.252422 IP6 fd00:1111::2.42773 > fd00:1111::1.bgp: Flags [.], ack 1, win 885, length 0 15:27:08.252457 IP6 fd00:1111::2.42773 > fd00:1111::1.bgp: Flags [P.], seq 1:48, ack 1, win 885, length 47: BGP 15:27:08.252501 IP6 fd00:1111::1.bgp > fd00:1111::2.42773: Flags [.], ack 48, win 222, length 0 15:27:08.253429 IP6 fd00:1111::1.bgp > fd00:1111::2.42773: Flags [R.], seq 1, ack 48, win 222, length 0 I do not really see where the problem may come from, the same configuration works with all my other peers. Thank you for your help ! -- Julien Sansonnens

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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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