February 2021 - Bird-users

OSPF Flapping
by Délsio Cabá 17 Feb '21

17 Feb '21

Hi all, We have 2 bird 2.0.7 instances rpm package running on vmware with MTU 9000 The only issue I cannot find is why they sessions are flapping: 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.126 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.125 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.126 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.125 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.126 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.125 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done 3w0d: %OSPF-5-ADJCHG: Process 1, Nbr 10.200.2.126 on TenGigabitEthernet0/2/0 from LOADING to FULL, Loading Done Below the relevant confi: 10.200.2.126 protocol ospf OSPF37697 { ipv4 { import none; export none; }; rfc1583compat yes; area 0 { networks {10.200.2.0/25;}; stub no; interface "*" { hello 10; dead 40; #dead count 100; retransmit 5; type ptmp; #real broadcast yes; authentication simple; password "Maputo12"; }; }; }

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No ASN in output when checking invalids ROAs with as-set
by Darren O'Connor 16 Feb '21

16 Feb '21

When checking ROAs, and the source ASN happens to have an AS-SET, bird does not output the ASN itself. Here is an example without an AS-SET: $ birdc 'show route primary table master4 where roa_check(roa_v4, net, bgp_path.last_nonaggregated) = ROA_INVALID' | grep 186.28 186.28.232.0/24 unreachable [BGP1v4 2021-02-11 from 46.30.8.72] * (100) [AS263710i] Here is an example with an AS-SET: $ birdc 'show route primary table master4 where roa_check(roa_v4, net, bgp_path.last_nonaggregated) = ROA_INVALID' | grep 185.186 185.186.206.0/24 unreachable [BGP3v4 2021-02-07 from 192.110.255.57] * (100) [?] The source ASN in the first shows as 263710, but the second shows none at all. This is the actual live prefix for the second: bird> show route all for 185.186.206.0/24 Table master4: 185.186.206.0/24 unreachable [BGP3v4 2021-02-07 from 192.110.255.57] * (100) [?] Type: BGP univ BGP.origin: Incomplete BGP.as_path: 13030 8529 28885 {206350} As the query is specifying last_nonaggregated, I'd expect the output to contain that ASN. Thanks D

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Linux PBR and RIP
by Grant Taylor 14 Feb '21

14 Feb '21

Hi, I'm facing a problem where RIP (v2) isn't originating a default route if it's not in the (kernel) table that RIP is using. The system itself is using Policy Based Routing and does have a default route in a different (kernel) table. PBR is searching multiple (kernel) tables in succession. Is there a way that I can have BIRD v2 originate a default route that doesn't exist in the (kernel) table that RIP is connected to? Or am I facing needing another (BIRD) table that has the main kernel table and a static default route piped into so that RIP sees the default that the kernel isn't using? -- Grant. . . . unix || die

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[PATCH] BGP: Add support for BGP hostname capability
by Vincent Bernat 10 Feb '21

10 Feb '21

This is an implementation of draft-walton-bgp-hostname-capability-02. It's implemented since quite some time for FRR and in datacenter, this gives a nice output to avoid using IP addresses. Currently, it is always enabled. The hostname is retrieved from uname(2) and not configurable. The domain name is never set nor displayed. I don't think being able to set the hostname is very important. I don't think the domain name is useful. However, maybe the capability should not be enabled by default. Also, the case where the capability is supported but hostname is empty is handled as if the capability was not supported. I think this is not worth handling such an edge case. The RFC doesn't say if hostname is optional or not. The return code of uname(2) is not checked, but I think this is not bound to happen and if it happens, this is handled nicely by disabling the capability. The draft is expired but I hope a second implementation could allow to revive it. Output from BIRD: Local capabilities Multiprotocol AF announced: ipv6 Route refresh Graceful restart 4-octet AS numbers Enhanced refresh Long-lived graceful restart Hostname: bird2 Neighbor capabilities Multiprotocol AF announced: ipv6 Route refresh Graceful restart 4-octet AS numbers ADD-PATH RX: ipv6 TX: Hostname: frr1 Output from FRR: Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd PfxSnt bird1(2001:db8::11) 4 65000 548 495 0 0 0 00:03:06 0 0 bird2(2001:db8::12) 4 65000 281 256 0 0 0 00:01:49 0 0 frr2(2001:db8::22) 4 65000 501 501 0 0 0 00:24:56 0 0 Signed-off-by: Vincent Bernat <vincent(a)bernat.ch> --- proto/bgp/bgp.c | 3 +++ proto/bgp/bgp.h | 2 ++ proto/bgp/config.Y | 1 + proto/bgp/packets.c | 38 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 44 insertions(+) diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c index 302d026c0103..d4c15f0538b1 100644 --- a/proto/bgp/bgp.c +++ b/proto/bgp/bgp.c @@ -2415,6 +2415,9 @@ bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps) bgp_show_afis(-1006, " AF supported:", afl1, afn1); bgp_show_afis(-1006, " AF preserved:", afl2, afn2); } + + if (*caps->hostname) + cli_msg(-1006, " Hostname: %s", caps->hostname); } static void diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h index dd7dc28fd03d..3a99bc9667b5 100644 --- a/proto/bgp/bgp.h +++ b/proto/bgp/bgp.h @@ -98,6 +98,7 @@ struct bgp_config { int enable_refresh; /* Enable local support for route refresh [RFC 2918] */ int enable_as4; /* Enable local support for 4B AS numbers [RFC 6793] */ int enable_extended_messages; /* Enable local support for extended messages [draft] */ + int enable_hostname; /* Enable local support for hostname [draft] */ u32 rr_cluster_id; /* Route reflector cluster ID, if different from local ID */ int rr_client; /* Whether neighbor is RR client of me */ int rs_client; /* Whether neighbor is RS client of me */ @@ -225,6 +226,7 @@ struct bgp_caps { u16 gr_time; /* Graceful restart time in seconds */ u8 llgr_aware; /* Long-lived GR capability, RFC draft */ + char hostname[UINT8_MAX + 1]; /* Hostname, RFC draft */ u8 any_ext_next_hop; /* Bitwise OR of per-AF ext_next_hop */ u8 any_add_path; /* Bitwise OR of per-AF add_path */ diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y index 18c3560dfc9b..f8bd4ef03b11 100644 --- a/proto/bgp/config.Y +++ b/proto/bgp/config.Y @@ -62,6 +62,7 @@ bgp_proto_start: proto_start BGP { BGP_CFG->error_delay_time_max = 300; BGP_CFG->enable_refresh = 1; BGP_CFG->enable_as4 = 1; + BGP_CFG->enable_hostname = 1; BGP_CFG->capabilities = 2; BGP_CFG->interpret_communities = 1; BGP_CFG->allow_as_sets = 1; diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c index 78fdd1e006a3..71ab1be48b46 100644 --- a/proto/bgp/packets.c +++ b/proto/bgp/packets.c @@ -11,6 +11,7 @@ #undef LOCAL_DEBUG #include <stdlib.h> +#include <sys/utsname.h> #include "nest/bird.h" #include "nest/iface.h" @@ -221,6 +222,8 @@ bgp_prepare_capabilities(struct bgp_conn *conn) struct bgp_channel *c; struct bgp_caps *caps; struct bgp_af_caps *ac; + struct utsname uts = {}; + size_t length; if (!p->cf->capabilities) { @@ -252,6 +255,16 @@ bgp_prepare_capabilities(struct bgp_conn *conn) if (p->cf->llgr_mode) caps->llgr_aware = 1; + if (p->cf->enable_hostname) + { + uname(&uts); + if ((length = strlen(uts.nodename)) > UINT8_MAX) + length = UINT8_MAX; + memcpy(caps->hostname, uts.nodename, length); + caps->hostname[length] = 0; + } + + /* Allocate and fill per-AF fields */ WALK_LIST(c, p->p.channels) { @@ -295,6 +308,7 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf) struct bgp_af_caps *ac; byte *buf_head = buf; byte *data; + size_t length; /* Create capability list in buffer */ @@ -412,6 +426,24 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf) data[-1] = buf - data; } + if (*caps->hostname) + { + *buf++ = 73; /* Capability 73: Hostname */ + *buf++ = 0; /* Capability data length */ + data = buf; + + /* Hostname */ + length = strlen(caps->hostname); + *buf++ = length; + memcpy(buf, caps->hostname, length); + buf += length; + + /* Domain, not implemented */ + *buf++ = 0; + + data[-1] = buf - data; + } + caps->length = buf - buf_head; return buf; @@ -573,6 +605,12 @@ bgp_read_capabilities(struct bgp_conn *conn, byte *pos, int len) } break; + case 73: /* Hostname, RFC draft */ + if (cl < 2 || cl < 2 + pos[2]) + goto err; + + memcpy(caps->hostname, pos + 3, pos[2]); + /* We can safely ignore all other capabilities */ } -- 2.30.0

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Can't connect new router to OSPF
by ico 09 Feb '21

09 Feb '21

Hello, I am reaching to you bird guys, because I run out of ideas, how to make my new router with bird 2.0.7 connect to the rest of OSPF routers. The server is linux, kernel 5.10.12. IP config of interface connected to entwork: $ ip a ls dev eth0 20: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 38:ea:a7:12:11:f4 brd ff:ff:ff:ff:ff:ff inet 10.10.4.45/24 scope global eth0 valid_lft forever preferred_lft forever This interface is perfectly OK I believe, since I am connecting to the router via this interface. Bird's config (minimal, to show the problem): $ cat /etc/bird/bird.conf log stderr { debug, info, remote, warning, error, auth, fatal, bug }; router id 10.10.4.45; debug protocols all; protocol device { scan time 3; } protocol ospf ospfin { ipv4 { import all; export all; }; tick 2; ecmp no; area 0.0.0.0 { stub no; interface "eth0" { hello 5; retransmit 2; wait 10; dead 20; authentication cryptographic; password "somepass"; check link yes; }; }; } I run the bird 2.0.7 like this: $ bird -c /etc/bird/bird.conf -f 2021-02-09 18:11:04.277 <WARN> Missing broadcast address for interface eth0 2021-02-09 18:11:04.277 <WARN> Missing broadcast address for interface eth1 2021-02-09 18:11:04.277 <INFO> Started ...and that's all, no more logs. Interface eth1 is 2nd interface with IP address on router, but not configured in OSPF. In bird console I see this: bird> show ospf neighbors ospfin: Router ID Pri State DTime Interface Router IP 10.10.4.15 1 Init/Other 15.722 eth0 10.10.4.15 10.10.4.12 1 Init/Other 18.014 eth0 10.10.4.12 Other OSPF routers on network 10.10.4.0/24 (12 of them) communicate without problems. Those routers run bird 1.6.x but that shouldn't be a problem, I also have some birds 2.0.7 in other parts of network. On other routers I don's see this one as a neighbor. Once or twice it was ther, but don't know why... In those times I saw this: router 10.10.4.45 unreachable network [10.10.4.1] metric 10 OK. I suspect the problem has something to do with "Missing broadcast address.." messages. Maybe some misconfiguration? Or some obvious error I don't see. Please point me to error I am doing. Thanks ico

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JSON Route Table Displays
by Jay Hanke 08 Feb '21

08 Feb '21

Is it possible to output the BIRD route table in JSON format from birdc? Jay

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Socket: Permission denied
by shirenn 08 Feb '21

08 Feb '21

Hello, I am setting up bird for my AS. I have two routers A and B and my ISP gives me a peer C to do bgp with. The first session initiate without any problem. but when I start the second one, I get the following error : zayo BGP master start 12:44:11 Active Socket: Permission denied debug doesn't give me more information and I couldn't found online what is this error. Could you help me understand it please :) ? And I had another question about router id, in the configuration file, it is said that the router id should be an IPv6. But when I put my IPv6 in it, I get the following error : bird: /etc/bird/bird6.conf:21:11 Router IDs must be entered as hexadecimal numbers or IPv4 addresses in IPv6 version Bests, -- shirenn

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Re: [PATCH] BGP: Add support for BGP hostname capability
by Job Snijders 03 Feb '21

03 Feb '21

Dear Vincent, Thank you for your contribution, running code always is an excellent way to move specifications for the purpose of interopability forward. I'd like to comment on my favorite topic... *** DEFAULTS **** :-) On Wed Feb 3 19:19:50 CET 202, you wrote: > > However, maybe the capability should not be enabled by default. > Indeed, it should absolutely not be enabled by default. Enabling a feature like this would violate the principle of least astonishment! :) Other than POLA, there are few more reasons it probably shouldn't be enabled by default: i recall the draft's supporters alleged this feature is useful in context of 'datacenter networks' (aka, 'non-Internet'?). This to me means that as only a small subset of users care about it, and the onus is on them to enable it if they wish to use this feature. The draft being in draft status, and not (yet?) been adopted by the IETF IDR working group is another reason not to enable it by default. Thirdly, the semantics of the mechanism are not entirely well aligned with the mechanics of a node's hostname. A node's hostname can change (often?) over the lifetime of the node, while signaling the hostname through a BGP capability effectively limits hostname exchange merely to the OPEN event, a single point in time. Lastly, many have argued that this is what we have Reverse DNS for, and then others argued that in ISIS the hostname also is flooded, so why not in BGP... and so on, making it clear there is no consensus what to do next. I recommend adjusting the patch in such a way that the capability is only exchanged with specific neighbors where the capability has been explicitly enabled through neighbor/group specific configuration. Kind regards, Job

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Order of prefixes in "show" command
by Muzalewska, Klara 03 Feb '21

03 Feb '21

Hi, In which order prefixes are displayed while doing : “show route table <table_name>” ? While doing this command with this same set of prefixes, it will always display in this same order? Best regards, Klara

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Duplicated routes received from Route Reflectors
by Délsio Cabá 02 Feb '21

02 Feb '21

Dear We have a installed 2 BIRD RR (10.200.2.125 and 10.200.2.124) just installed to use as reflectors on our network We noticed the client is adding 2 entries to the routing table. Is this normal? Taking into consideration we do full global BGP is will be too much memory wasted: RR-CLIENT#show ip bgp 0.0.0.0 BGP routing table entry for 0.0.0.0/0, version 0 Paths: (2 available, no best path) Not advertised to any peer Refresh Epoch 1 xxxx 10.200.0.252 (inaccessible) from 10.200.2.125 (10.200.2.125) Origin IGP, metric 0, localpref 350, valid, internal Community: 2470515592 Originator: 10.200.0.252, Cluster list: 10.200.2.125 rx pathid: 0, tx pathid: 0 Refresh Epoch 1 xxxx 10.200.0.252 (inaccessible) from 10.200.2.124 (10.200.2.124) Origin IGP, metric 0, localpref 350, valid, internal Community: 2470515592 Originator: 10.200.0.252, Cluster list: 10.200.2.124 rx pathid: 0, tx pathid: 0 2.125 config: https://pastebin.com/jUh0ZQ6h 2.124 config: https://pastebin.com/5dhx94db

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