December 2016 - Bird-users

Version 1.6.3
by Ondrej Filip 23 Dec '16

23 Dec '16

Dear users, a new version of the 1.6.x branch is out: Version 1.6.3 o Large BGP communities o BFD authentication (MD5, SHA1) o SHA1 and SHA2 authentication for RIP and OSPF o Improved documentation o Several bug fixes This is meant to be a stable version. An upgrade is recommended. Enjoy it! And Merry Xmas! Ondrej

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Re: BIRD patches for IP-in-IP
by Mohammad Banikazemi 22 Dec '16

22 Dec '16

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Dynamic cost?
by Mike Jones 22 Dec '16

22 Dec '16

Hi, I have an OSPF based network using bird for routing the core and it seems to work fine, however the network is geographically diverse and some of the routing is sub-optimal. Specifically, the default route is going shortest hops rather than lowest latency. What I would like to do is have the OSPF cost reflect the latency of the link, however I am having a problem coming up with a scalable/automated way of doing this. As far as I can tell there is no built in "latency to peer" I can reference? I could configure a manual entry for each peer in the config file, however that doesn't seem very manageable, even with some kind of script to generate the config file. >From what I can gather there is no way for a filter to reference an external file/database/script to adjust the routes on import. I even considered a convoluted approach of having a script inject the peers IP address in to a special kernel table and using the route metric to feed numbers in to bird, but couldn't find a way of storing the data and referencing it on a later route lookup. Basically what I want is that when an OSPF peer comes up I ping it then set the cost for all routes received from that neighbour to the latency (with some basic sanity like a min and max). I don't expect the latency to vary much once a link is up, however I do need to auto-discover new peers appearing on the network. Any ideas? Thanks - Mike Jones

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BIRD 1.6.2 removes IPv6 kernel routes
by Robert Sander 21 Dec '16

21 Dec '16

Hi, I have an issue with BIRD 1.6.2 from http://bird.network.cz/debian/ on Debian jessie: When bird6 is running and I "ifup" an interface with a static IPv6 address the address is added but no IPv6 route in the associated network via that interface. When bird6 is not running everything works. It looks like bird6 1.6.2 is eating IPv6 routes set by the kernel. I have not encountered this issue with the IPv4 bird daemon. After downgrading to bird 1.4.5 from Debian jessie everything works as expected. What information do you need? Regards -- Robert Sander Heinlein Support GmbH Schwedter Str. 8/9b, 10119 Berlin http://www.heinlein-support.de Tel: 030 / 405051-43 Fax: 030 / 405051-19 Zwangsangaben lt. §35a GmbHG: HRB 93818 B / Amtsgericht Berlin-Charlottenburg, Geschäftsführer: Peer Heinlein -- Sitz: Berlin

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bird incorrectly merging next hops
by Bernardo Figueiredo 15 Dec '16

15 Dec '16

Hi, At our network we use bird in all our Linux routers so they talk OSPF. Recently we added a new router appliance(not Linux) to the backbone and most of the bird routers showed wrong next hops for some routes. At first we tought that the problem might be caused by a bug in the appliance making it send bad LSAs, but debugging the ospf packets and looking at other non-bird router appliances made us certain that the fault was in bird. After looking through the code we found that the bug is in function 'ospf_ext_spf' in file 'proto/ospf/rt.c'. The variable 'nfa' of type 'struct orta' is not totally cleaned before each start of the 'WALK_SLIST' loop, and can have a wrong value of 'nfa.nhs_reuse = 1' instead of 'nfa.nhs_reuse = 0', which is what triggers the bug. The fix is to put the declaration of 'orta nfa = {};' inside the loop, so the variable is clean at the start of each loop. Alternatively at the start of each loop you could set 'nfa.nhs_reuse = 0'. The bug only occurs when the following options are in bird.conf: ecmp yes; merge external yes; At least from what I saw the bug affects versions '2.0', '1.6.2' and '1.5'. If some of the explanation is not clear please tell me and I'll try to write it better. I'll provide a more in-depth explanation now: the relevant code is: the code is 'tagged' with 'x->' which are the relevant points for trigerring the bug static void ospf_ext_spf(struct ospf_proto *p) { ort *nf1, *nf2; 0->orta nfa = {}; ip_addr rtid; OSPF_TRACE(D_EVENTS, "Starting routing table calculation for ext routes"); WALK_SLIST(en, p->lsal) { /*not showing LSA validation*/ rtid = ipa_from_rid(en->lsa.rt); 1-> nf1 = fib_find(&atmp->rtr, &rtid, MAX_PREFIX_LENGTH); /*not showing other validations*/ if (!rt.fbit) { nf2 = nf1; 2-> nfa.nhs = nf1->n.nhs; br_metric = nf1->n.metric1; } else { nf2 = ospf_fib_route(&p->rtf, rt.fwaddr, MAX_PREFIX_LENGTH); if (!nf2) { continue; } /*not showing some validations*/ nfa.nhs = nf2->n.nhs; br_metric = nf2->n.metric1; if (has_device_nexthops(nfa.nhs)) { nfa.nhs = fix_device_nexthops(p, nfa.nhs, rt.fwaddr); 3-> nfa.nhs_reuse = 1; } } /*not showing setting other attributes in 'nfa'*/ 4-> ri_install_ext(p, rt.ip, rt.pxlen, &nfa); } } static inline void ri_install_ext(struct ospf_proto *p, ip_addr prefix, int pxlen, const orta *new) { 5->ort *old = (ort *) fib_get(&p->rtf, &prefix, pxlen); int cmp = orta_compare_ext(p, new, &old->n); if (cmp > 0) { ort_replace(old, new); } else if (cmp == 0) { 6-> ort_merge_ext(p, old, new); } } static void ort_merge_ext(struct ospf_proto *p, ort *o, const orta *new) { orta *old = &o->n; if (old->nhs != new->nhs) { 7-> old->nhs = mpnh_merge(old->nhs, new->nhs, old->nhs_reuse, new- >nhs_reuse, p->ecmp, p->nhpool); old->nhs_reuse = 1; } /* not showing code that sets other attributes */ } struct mpnh * mpnh_merge(struct mpnh *x, struct mpnh *y, int rx, int ry, int max, linpool *lp) { struct mpnh *root = NULL; struct mpnh **n = &root; while ((x || y) && max--) { int cmp = mpnh_compare_node(x, y); if (cmp < 0) { *n = rx ? x : mpnh_copy_node(x, lp); x = x->next; } else if (cmp > 0) { 8-> *n = ry ? y : mpnh_copy_node(y, lp); y = y->next; } else { 9-> *n = rx ? x : (ry ? y : mpnh_copy_node(x, lp)); x = x->next; y = y->next; } n = &((*n)->next); } *n = NULL; return root; } conditions to trigger the bug: * while in the loop there must be a LSA that has a forwading address which routes satisfy the conditions to trigger 'has_device_nexthops' so 'nfa.nhs_reuse' is set to 1, this corresponds to '3->'. Afterwards the bug could be trigger in any LSA that has the following properties: * LSA forwarding address equal to 0.0.0.0; so we set 'nfa' to the route to the router that sent the LSA. This last route is the one might be corrupted. This corresponds to '1->' and '2->'; * the route passes the validations to be installed in the OSPF routing table. This corresponds to '4->' * the old route that we had for the destination on the LSA is equally good to the new route that we are installing so we decide to merge them. This corresponds to '5->' and '6->' * The routes aren't the same instance so we decide to merge them. '7->' * While merging the next hop list we must compare at least one next hop from the 'new' route higher than a next hop from the 'old' route so we enter '8->' and wrongly not copy the next hop because 'ry = 1' due to 'nfa.nhs_reuse = 1'. This might also happen in '9->' if the next hops compare equal, but I haven't checked.

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LSA ID collision issue is seen with OSPF stub-networks configured and BIRD is acting as ABR
by naveen chowdary Yerramneni 13 Dec '16

13 Dec '16

Hi, *Issue Description*: LSA ID collision issue is seen with OSPF *stub-networks* configured and BIRD is acting as ABR *BIRD OSPF configuration*: · Part of 2 areas (say, area-0 and area-100) · Stub-networks are configured in area-0 *Code Flow*: 1. Stubnets are advertised to area-0 by generating router LSA ( LSA_T_RT). o ospf_disp() -> ospf_update_topology() -> ospf_originate_rt_lsa()->ospf_ originate_lsa() 2. Now, stubnets are added to top graph table (p->gr) with LSA type LSA_T_RT 3. When creating routing table, these stubnets are added to FIB ( p->rtf). o ospf_disp() -> ospf_rt_spf() -> ospf_rt_spfa() -> spfa_process_rt() -> add_network() -> ri_install_net() 4. When BIRD is acting as ABR then, walk through FIB(p->rtf) and send summary LSA (LSA_T_SUM_NET) with LSA mode as LSA_M_RTCALC. Also, nf pointer is set (stores fib node address) in top_hash_entry. o ospf_disp() -> ospf_rt_abr2() -> check_sum_net_lsa() -> ospf_originate_sum_net_lsa() ->ospf_originate_lsa() 5. Now, stubnets are added to top graph table (p->gr) with LSA type LSA_T_SUM_NET 6. Stubnets are removed from FIB(p->rtf) o ospf_disp() -> rt_sync() -> fib_delete() 7. Now, stubnets entries are still present in top graph table (Note: fib_delte() doesn't free the node, it just moves the fib node to free pool, fib_node pointer is still valid) 8. With any change in network, ospf_rt_spf()is called. In ospf_rt_reset(), LSA mode is updated fromLSA_M_RTCALC to LSA_M_STALE. 9. Again, steps 3-6 are repeated. In step-3, fib node pointer is changed and in step-4, fib node pointer comparison fails in ospf_originate_lsa()which is leading to LSA id collision. *Issue is resolved with below code change. *Please review the change and provide your comments. Also, please let me know if any other information is required. diff -rupN bird/proto/ospf/topology.c bird_modified/proto/ospf/topology.c --- bird/proto/ospf/topology.c 2016-11-28 05:14:19.582761752 -0800 +++ bird_modified/proto/ospf/topology.c 2016-11-28 05:14:01.270761752 -0800 @@ -278,7 +278,7 @@ ospf_originate_lsa(struct ospf_proto *p, if (!SNODE_VALID(en)) s_add_tail(&p->lsal, SNODE en); - if (!en->nf || !en->lsa_body) + if (!en->nf || !en->lsa_body || en->mode == LSA_M_STALE) en->nf = lsa->nf; Thanks, Naveen

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How does BIRD detect the connected network type for ospf neighbor
by Wei Huang 13 Dec '16

13 Dec '16

When I set my ospf interface eth1's address to be 10.2.1.2/30, neighbor router ethernet interface IP address to be 10.2.1.1/30, the neighbor shows it's PTP type: bird> sh ospf neighbors ospf_rdomain_0: Router ID Pri State DTime Interface Router IP 172.16.20.76 1 Full/PtP 00:35 vni-0 10.2.1.1 If I change the interfaces' IP address to be 10.2.1.x/24 or I force interface type to be bcast in Bird's ospf config, it shows as bird> sh ospf neighbors ospf_rdomain_0: Router ID Pri State DTime Interface Router IP 172.16.20.76 1 Full/DR 00:35 vni-0 10.2.1.1 My question is how does Bird detect the connected network type? Thanks, Wei

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Multiple RIBs complexity
by Antonio Modesto 11 Dec '16

11 Dec '16

Hi everyone, How efficient is BIRD to calculate the best paths for multiples routing tables? I'm thinking about doing some PBR in our network to avoid some situations, for example: IX | +---------------+ | | AS100 --------- MYAS ------------TRANSIT What happens here is that I'm supposed to provide transit to AS100 directly. The problem arrises when AS100 announces a more specific route to the IX. At this point MYAS starts delivering the traffic throught the IX infraestructure, bypassing bandwidth control. Having a second FIB assigned to the TRANSIT interface that does not contain IX routes would solve the problem. I'm just worried about the CPU utilization for processing the best paths for two different routing tables. Regards. -- Atenciosamente, Antônio Modesto

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bird6 1.6.2 hangs doing recvmsg on netlink socket
by Israel G. Lugo 09 Dec '16

09 Dec '16

Hello, I am getting some random crashes in bird6, running on Debian, version 1.6.2-1~bpo8+1 from your http://bird.network.cz/debian/ repository. I've got a single OSPF instance with 74 routes, one eBGP session receiving a default route, and one iBGP session with another Bird router, which sends me its own default. What happens is that, from time to time, bird6 becomes stuck in an infinite loop doing recvmsg() on a netlink socket, and IPv6 routes are lost. The interval seems random; it's been 3 days, and it's also been 2 weeks. gk1 # strace -p 11465 recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) recvmsg(7, 0x7ffe8cfecb70, 0) = -1 EAGAIN (Resource temporarily unavailable) [...] File descriptor 7 is a netlink socket: gk1 # lsof -p 11465 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME bird6 11465 bird cwd DIR 253,0 4096 2 / bird6 11465 bird rtd DIR 253,0 4096 2 / bird6 11465 bird txt REG 253,0 540648 787381 /usr/sbin/bird6 bird6 11465 bird mem REG 253,0 47712 659204 /lib/x86_64-linux-gnu/libnss_files-2.19.so bird6 11465 bird mem REG 253,0 43592 659208 /lib/x86_64-linux-gnu/libnss_nis-2.19.so bird6 11465 bird mem REG 253,0 89104 659199 /lib/x86_64-linux-gnu/libnsl-2.19.so bird6 11465 bird mem REG 253,0 31632 659200 /lib/x86_64-linux-gnu/libnss_compat-2.19.so bird6 11465 bird mem REG 253,0 1738176 659160 /lib/x86_64-linux-gnu/libc-2.19.so bird6 11465 bird mem REG 253,0 137440 655379 /lib/x86_64-linux-gnu/libpthread-2.19.so bird6 11465 bird mem REG 253,0 140928 655799 /lib/x86_64-linux-gnu/ld-2.19.so bird6 11465 bird 0u CHR 1,3 0t0 1028 /dev/null bird6 11465 bird 1u CHR 1,3 0t0 1028 /dev/null bird6 11465 bird 2u CHR 1,3 0t0 1028 /dev/null bird6 11465 bird 3u unix 0xffff8803269f7c00 0t0 127941139 socket bird6 11465 bird 4u unix 0xffff8803269f7480 0t0 127941145 /run/bird/bird6.ctl bird6 11465 bird 5u netlink 0t0 127906248 ROUTE bird6 11465 bird 6u netlink 0t0 127906249 ROUTE bird6 11465 bird 7u netlink 0t0 127906250 ROUTE bird6 11465 bird 8u IPv6 127906251 0t0 TCP *:bgp (LISTEN) bird6 11465 bird 9u raw6 0t0 127906252 00000000000000000000000000000000:0059->00000000000000000000000000000000:0000 st=07 bird6 11465 bird 10u IPv6 127994711 0t0 TCP e0.gk1:bgp->e0.gk2:39074 (CLOSE_WAIT) bird6 11465 bird 11u IPv6 127965176 0t0 TCP [2001:w:y:x::133]:58268->[2001:w:y:x::1]:bgp (CLOSE_WAIT) Unfortunately I didn't find any debug symbols for this package, so all I could get from gdb was the following: (gdb) bt #0 0x00007f5ad1705e80 in __recvmsg_nocancel () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f5ad1b90428 in ?? () #2 0x00007f5ad1b8956b in ?? () #3 0x00007f5ad1b8a06b in ?? () #4 0x00007f5ad1b3f0c7 in ?? () #5 0x00007f5ad136db45 in __libc_start_main (main=0x7f5ad1b3eb10, argc=5, argv=0x7ffe8cfece28, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffe8cfece18) at libc-start.c:287 #6 0x00007f5ad1b3f3ec in ?? () (gdb) info r rax 0xfffffffffffffff5 -11 rbx 0x7f5ad32aefe0 140028066590688 rcx 0xffffffffffffffff -1 rdx 0x0 0 rsi 0x7ffe8cfecb70 140731263929200 rdi 0x7 7 rbp 0x7f5ad1dba270 0x7f5ad1dba270 rsp 0x7ffe8cfecb18 0x7ffe8cfecb18 r8 0x7f5ad32aefe0 140028066590688 r9 0x0 0 r10 0x1 1 r11 0x246 582 r12 0x0 0 r13 0x7f5ad32c7f60 140028066692960 r14 0x100 256 r15 0x0 0 rip 0x7f5ad1705e80 0x7f5ad1705e80 <__recvmsg_nocancel+7> eflags 0x246 [ PF ZF IF ] cs 0x33 51 ss 0x2b 43 ds 0x0 0 es 0x0 0 fs 0x0 0 gs 0x0 0 Unfortunately, I did not have debug on when this crashed. I had it on for several days, but either I was "lucky" or the debug prevented the crash somehow. I was having several MB worth of debug logs every day, so I ended up disabling debug. I'm not 100% sure that this was installed from your CZ repository, it may have been from Debian backports. But I'm 95% sure it came from CZ. In any case the MD5 is as follows: 56e48e8e5a1380b384f1758df2077e53 bird_1.6.2-1~bpo8+1_amd64.deb I have now upgraded to 1.6.2-3~bpo8+1, from your CZ repository. I can provide the configuration file off-list, if that helps. Regards, Israel

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problem configuring ptmp
by Maria P 08 Dec '16

08 Dec '16

Hi Everyone, I try to get a mixed network of linux and Mikrotik running, useing ptmp interfaces. It worked with quagga, but I wanna switch due to software instabilities. At least with Mikrotik & quagga I understand that a ptmp area means Hellos are propagated by multicasts to 224.0.0.5, the neighbors form ptp relations with each other after they have found themselfs. with my configuration, Bird doesn't send out multicasts, evenso its logging "ospf1: HELLO packet sent via eth0" what am I doing wrong ? Thanks Maria my config ---- log syslog all; router id 172.20.2.33; debug protocols all; protocol direct { interface "*"; # Restrict network interfaces it works with } protocol kernel { persist; # Don't remove routes on bird shutdown scan time 20; # Scan kernel routin export all; # Default is export none } protocol device { scan time 10; # Scan interfaces every 10 seconds } protocol static { import all; export all; } protocol ospf { import all; export all; area 0.0.0.0 { stub no; networks {192.168.23.0/24;}; interface "eth0" { priority 1; type ptmp; authentication simple; password "***deleted***"; cost 2; }; }; }

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