- Bird-users - Mailing Lists

A study on community-triggered updates in BGP
by Thomas Krenc 19 Oct '20

19 Oct '20

Dear BIRD users and developers, As a team of researchers from NPS and TU Berlin, we are investigating the impact of BGP community attributes on the update behavior between ASes. We find that when a route is associated with multiple distinct community attributes it does not only lead to multiple announcement at the tagging AS, but also at neighboring ASes, if communities are not filtered properly. This behavior is wide-spread. In order to better understand our observations, we have performed a series of laboratory experiments using Cisco IOS, Junos OS, as well as the BIRD daemon. We find that - by default - all routers generate announcements with changing community attributes, even when other attributes do not change. In addition, when communities are filtered at egress, Cisco und BIRD send duplicate announcements (Juniper does not). Is this side-effect known to the BIRD community and would you consider it a bug or a feature? Since our findings are limited to observations in public data as well as few router implementations, we would like to share our research and kindly ask you to have a look at: https://www.cmand.org/communityexploration/ There, we provide some resources documenting our research, as well as open questions. We greatly appreciate any feedback and insights you can offer. Also, please don't hesitate to contact us directly: communityexploration AT cmand DOT org best regards Thomas Krenc Postdoctoral Researcher Naval Postgraduate School

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roa_check RPKI
by Fabiano D'Agostino 11 Oct '20

11 Oct '20

How does roa_check(roa_table,net,bgp_path.last) work? Having such a ROA as example: origin AS: 64513 prefix: 78.150.40.0/20 max mask: 24 and a BGP announcement: origin AS: 64514 prefix: 78.150.45.0/22 so it's as invalid, but how does this check work? roa_table: validated roa record (validated cache) net: should be the current prefix so 78.150.45.0/22 what is bgp_path.last and how does roa_check function do the check? Thanks, Fabiano

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[Bug] Multiple BFD protocol instances for one VRF should be prohibited
by Wang Shanker 10 Oct '20

10 Oct '20

Hi, all Before commit `f9deedf1`, BFD was implemented allowing only one instance of BFD protocol. The implementation was not prepared for multiple BFD protocol instances. In that commit, to support VRF, the check for multiple BFD instances was removed, which results in the possibility that multiple BFD protocol instances are configured for one VRF. `bfd_add_request()` will success only if given `bfd_proto` and `bfd_request` belong to the same VRF. So for each VRF, only the first BFD protocol instance will take effect. This can be reproduced by the following configuration with the latest commit in branch legacy and similar configuration with the latest commit in branch master: ``` router id 192.168.0.1; protocol bfd bfd1{ interface "eth0" { interval 5s; idle tx interval 5s; }; }; protocol bfd bfd2{ interface "eth1" { interval 10s; idle tx interval 10s; }; }; protocol device { }; protocol static { route 2001:db8::/32 multipath via fe80::1%eth0 bfd via fe80::2%eth1 bfd ; }; ``` As shown in `show bfd session`, the configuration in instance `bfd2` is ignored: ``` # ./birdc -s bird6.ctl sh bfd sess bfd1 BIRD 1.6.8 ready. bfd1: IP address Interface State Since Interval Timeout fe80::2 eth1 Down 03:51:32 1.000 0.000 fe80::1 eth0 Down 03:51:32 5.000 0.000 # ./birdc -s bird6.ctl sh bfd sess bfd2 BIRD 1.6.8 ready. bfd2: IP address Interface State Since Interval Timeout ``` Expected behavior: I suggest such configuration be seen invalid and rejected when parsed. Cheers, Miao Wang

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typo in 2.x bird documentation.
by Sergey Kulikov 05 Oct '20

05 Oct '20

I was writing import filter to use with both v4 and v6 prefixes and set krt_prefsrc, so I need to identify prefix belonging to v4 or v6. So docs saying this: "Whether the address is IPv4 or not may be checked by .is_ip4 which returns a bool." But it's not working, and as I can see from sources in fact correct name for that function is ".is_v4" in config.Y: | term '.' IS_V4 { $$ = f_new_inst(FI_IS_V4, $1); } and it works, is this mailing list correct place to report this typo? Other users can experience issues trying to use ".is_ip4". -- Best regards, Sergey mailto:serg@rangerovers.ru

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Nexthop/nexthop groups question
by Alexander V. Chernikov 03 Oct '20

03 Oct '20

Hi folks, Cumulus people implemented nexthop objects/nexthop groups [1] in Linux kernel some time ago. These changes allow for more efficient communications between kernel and userspace w/ wide multipath & large amount of routes. Initial support landed [2] in FRR in 2019 and has notably improved since then. Are there any plans to support this functionality in bird? [1]: https://linuxplumbersconf.org/event/4/contributions/434/attachments/251/436… [2]: https://github.com/FRRouting/frr/commit/50d8965075cf59744dde685ae01400d9b7e… /Alexander

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Unable to build Bird2 with --with-protocols=bgp
by Nabeel Omer 30 Sep '20

30 Sep '20

Hi Everyone, I am trying to build Bird2 with `./configure --with-protocols=bgp` and it prints the following information: ubuntu@ip-172-26-14-214:~/bird$ make MKDIR -p obj/client obj/conf obj/doc obj/filter obj/lib obj/nest obj/test obj/proto/bgp obj/sysdep/linux obj/sysdep/unix obj/doc m4 -s -P conf/gen_parser.m4 conf/confbase.Y conf/flowspec.Y client/cmds.Y filter/config.Y nest/config.Y proto/bgp/config.Y sysdep/linux/netlink.Y sysdep/unix/config.Y sysdep/unix/krt.Y >obj/conf/cf-parse.y bison -Dparse.lac=full -Dparse.error=verbose -dv -pcf_ -b obj/conf/cf-parse obj/conf/cf-parse.y conf/gen_parser.m4: warning: 11 nonterminals useless in grammar [-Wother] conf/gen_parser.m4: warning: 34 rules useless in grammar [-Wother] conf/confbase.Y:111.13-29: warning: nonterminal useless in grammar: label_stack_start [-Wother] %type <mls> label_stack_start label_stack ^^^^^^^^^^^^^^^^^ conf/confbase.Y:111.31-41: warning: nonterminal useless in grammar: label_stack [-Wother] %type <mls> label_stack_start label_stack ^^^^^^^^^^^ conf/confbase.Y:107.22-25: warning: nonterminal useless in grammar: time [-Wother] %type <time> expr_us time ^^^^ nest/config.Y:94.162-164: warning: nonterminal useless in grammar: tos [-Wother] %token END CLI_MARKER INVALID_TOKEN ELSECOL DDOT ^^^ nest/config.Y:438.1-13: warning: nonterminal useless in grammar: password_list [-Wother] And gets stuck. Does not produce any further output and doesn’t quit. Ctrl+C produces the following output: conf/Makefile:23: recipe for target 'obj/conf/cf-parse.tab.c' failed make: *** [obj/conf/cf-parse.tab.c] Interrupt Does anyone have any idea about why this might be happening? I am able to build successfully without passing --with-protocols=bgp to autoconf. Thanks, Nabeel Omer https://nabeelomer.me

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Reload filter used in protocol?
by Bernd Naumann 30 Sep '20

30 Sep '20

Hi *, Again, I have "such" a question... If I can reload (or restart) a single protocol, would that also re-read the filter used for that protocol? Or would do I need `configure` anyway? Thanks again! Bernd

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Dump/Show current running config?
by Bernd Naumann 29 Sep '20

29 Sep '20

Hi *, Sorry if this was asked before but my googlefu didn't provide me anything. Is there in bird 1.7 (or in 2.0) a feature to show or dump the current loaded/running config? If not: Is this on the roadmap somewhere? (Or is it somehow complicated to translate the config back into the syntax used in the conf-file?) Thanks. Bernd

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[BIRD 1.6.x] Unix: fix compilation with GCC 10
by Vincent Bernat 28 Sep '20

28 Sep '20

GCC 10 will now error when declaring a global variable twice: https://gcc.gnu.org/gcc-10/porting_to.html#common Fix this issue by declaring the variable as `extern' in `krt.h'. The variable is really declared in `krt.c'. LD -r -o all.o cf-parse.tab.o cf-lex.o conf.o /usr/bin/ld: cf-lex.o:/home/bernat/code/exoscale/bird/build~/conf/../lib/krt.h:115: multiple definition of `kif_proto'; cf-parse.tab.o:/home/bernat/code/exoscale/bird/build~/conf/../lib/krt.h:115: first defined here This issue was already fixed in BIRD 2.x. --- sysdep/unix/krt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sysdep/unix/krt.h b/sysdep/unix/krt.h index d4a8717e38ec..fe79efc3717d 100644 --- a/sysdep/unix/krt.h +++ b/sysdep/unix/krt.h @@ -112,7 +112,7 @@ struct kif_proto { struct kif_state sys; /* Sysdep state */ }; -struct kif_proto *kif_proto; +extern struct kif_proto *kif_proto; #define KIF_CF ((struct kif_config *)p->p.cf) -- 2.28.0

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Master ready for 2.0.8?
by Kenth Eriksson 28 Sep '20

28 Sep '20

Hi! Is master ready for a 2.0.8 release? The 2.0.7 release has several bugs that I think are worth a release to a broader audience (seems like they are all in master) * OSPF authentication causes SEGV https://bird.network.cz/pipermail/bird-users/2020-January/014174.html * No LPM on static routes https://bird.network.cz/pipermail/bird-users/2020-May/014563.html * Primary route flag corrupt https://bird.network.cz/pipermail/bird-users/2019-October/013931.html * Incorrect CLI output (fix continuation lines) https://bird.network.cz/pipermail/bird-users/2019-December/014019.html When looking thru master I found the following bug fixes are missing; * Multiple routes to the same network with different preference Looks like this is maintained in branch mq-ordered. Will mq-ordered branch merge into master? https://bird.network.cz/pipermail/bird-users/2019-October/013897.html * Socket close https://bird.network.cz/pipermail/bird-users/2019-June/013465.html * CLI socket buffer full https://bird.network.cz/pipermail/bird-users/2019-June/013464.html Thanks, Kenth

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