[BMP] BIRD socket best practice

[Maslanka, Pawel]

Hi BIRD team!

We found a case when BMP code is trying to connect with BMP collector service with sk_open(), this causes increasing CPU utilization. To reproduce this case, you have just:

  1.  Server machine where BMP PDU packets will be sent, should be reachable (so it can be pinged).
  2.  BMP collector service itself should not be running on this server.
  3.  Run BIRD with enabled BMP protocol.

After that you should observe that BIRD process has significantly increased CPU utilization. This is related somehow with “BIRD socket” because when I capture network traffic on host machine (where BIRD is running), I can see massive amount of TCP packets which are exchange between BIRD host machine and BMP collector machine. At the moment socket type related with BMP connection is SK_TCP_ACTIVE.
Do you have any idea what is going wrong or how BIRD socket should be properly use?
As a temporary fix, I have provided patch allows to avoid this issue but it is very ugly hack because it frees BIRD socket outside of IO code (sk_free()) and initialize again socket again every time when ECONNREFUSED error is passing to err_hook callback.

I need also a tip if there is a way to get notification from BIRD socket if we lost connection with BMP collector service? One option is to check if sk_send() failed but what in situation when there are no updates to send by longer time and I would like to get a notification ASAP when I lost connection with BMP collector service. Is this possible with current BIRD implementation or I should to add some timer's callback which will check somehow if BMP collector service is alive? This mechanism is needed for me to synchronize/re-send all BMP data to the collector.

Currently we have switched to BMP code provided on bmp branch from gitlab BIRD repo.

Additionally I have a question referring to enclosed code. Can I free list node and node data itself when sk_send() returns value greater or equal to 0 (>= 0), like in the below code?

  WALK_LIST_DELSAFE(tx_data, tx_data_next, p->tx_queue)
  {
    ...
    rv = sk_send(p->sk, data_size);
    if (rv < 0) {
      return;
    }

    mb_free(tx_data->data);
    rem_node((node *) tx_data);
    mb_free(tx_data);
    if (rv == 0) {
      return;
    }
    ...

Or I should to do that only if sk_send() return value greater than 0 (> 0) ? My goal is sending all data from list if there was only "temporary" problem with sk_send().


Thanks,
----


Pawel Maslanka
Senior Software Engineer

[signature_1256476543]


Office: +1.617.444.1234
Cell: +1.617.444.1234

Akamai Technologies
150 Broadway
Cambridge, MA 02142


Connect with Us:

[signature_580743884]<https://community.akamai.com/> [signature_1866338322] <http://blogs.akamai.com/>  [signature_2113959087] <https://twitter.com/akamai>  [signature_447607273] <http://www.facebook.com/AkamaiTechnologies>  [signature_1901210113] <http://www.linkedin.com/company/akamai-technologies>  [signature_1973184621] <http://www.youtube.com/user/akamaitechnologies?feature=results_main>



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 3614 bytes
Desc: image001.jpg
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 780 bytes
Desc: image002.jpg
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment-0001.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.png
Type: image/png
Size: 1445 bytes
Desc: image003.png
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image004.png
Type: image/png
Size: 1254 bytes
Desc: image004.png
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment-0001.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image005.png
Type: image/png
Size: 1238 bytes
Desc: image005.png
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image006.png
Type: image/png
Size: 1148 bytes
Desc: image006.png
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment-0003.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image007.png
Type: image/png
Size: 1307 bytes
Desc: image007.png
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment-0004.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bmp_connect_failed.patch
Type: application/octet-stream
Size: 5766 bytes
Desc: bmp_connect_failed.patch
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20210603/90461e5c/attachment.obj>