Hi Zhang, Awesome! Thanks!
Regards, Florin > On Mar 21, 2023, at 7:41 PM, Zhang Dongya <fortitude.zh...@gmail.com> wrote: > > Hi Florin, > > Thanks a lot, the previous patch and with reset disabled have been running 1 > day without issue. > > I will enable reset and with your new patch, will provide feedback later. > > Florin Coras <fcoras.li...@gmail.com <mailto:fcoras.li...@gmail.com>> > 于2023年3月22日周三 02:12写道： >> Hi, >> >> Okay, resetting of half-opens definitely not supported. I updated the patch >> to just clean them up on forced reset, without sending a reset to make sure >> session lookup table cleanup still happens. >> >> Regards, >> Florin >> >>> On Mar 20, 2023, at 9:13 PM, Zhang Dongya <fortitude.zh...@gmail.com >>> <mailto:fortitude.zh...@gmail.com>> wrote: >>> >>> Hi, >>> >>> After review my code, I found that I have add a flag to the vnet_disconnect >>> API which will call session_reset instead of session_close, the reason I do >>> this is to make intermediate firewall just flush the state and reconstruct >>> if I later reconnect. >>> >>> It seems in session_reset logic, for half open session, it also missing to >>> remove the session from the lookup hash which may cause the issue too. >>> >>> I change my code and will test with your patch along, will provide feedback >>> later. >>> >>> I also noticed the bihash issue discussed in the list recently, I will >>> merge later. >>> >>> Florin Coras <fcoras.li...@gmail.com <mailto:fcoras.li...@gmail.com>> >>> 于2023年3月21日周二 11:56写道： >>>> Hi, >>>> >>>> That last thing is pretty interesting. It’s either the issue fixed by this >>>> patch [1] or sessions are somehow cleaned up multiple times. If it’s the >>>> latter, I’d really like to understand how that happens. >>>> >>>> Regards, >>>> Florin >>>> >>>> [1] https://gerrit.fd.io/r/c/vpp/+/38507 >>>> >>>>> On Mar 20, 2023, at 6:52 PM, Zhang Dongya <fortitude.zh...@gmail.com >>>>> <mailto:fortitude.zh...@gmail.com>> wrote: >>>>> >>>>> Hi, >>>>> >>>>> After merge this patch and update the test environment, the issue still >>>>> persists. >>>>> >>>>> Let me clear my client app config: >>>>> 1. register a reset callback, which will call vnet_disconnect there and >>>>> also trigger reconnect by send event to the ctrl process.) >>>>> 2. register a connected callback, which will handle connect err by >>>>> trigger reconnect, on success, it will record session handle and extract >>>>> tcp sequence for our app usage. >>>>> 3. register a disconnect callback, which basically do same as reset >>>>> callback. >>>>> 4. register a cleanup callback and accept callback, which basically make >>>>> the session layer happy without actually relevant work to do. >>>>> >>>>> There is a ctrl process in mater, which will handle periodically >>>>> reconnect or triggered by event. >>>>> >>>>> BTW, I also see frequently warning 'session %u hash delete rv -3' in >>>>> session_delete in my environment, hope this helps to investigate. >>>>> >>>>> Florin Coras <fcoras.li...@gmail.com <mailto:fcoras.li...@gmail.com>> >>>>> 于2023年3月20日周一 23:29写道： >>>>>> Hi, >>>>>> >>>>>> Understood and yes, connect will synchronously fail if port is not >>>>>> available, so you should be able to retry it later. >>>>>> >>>>>> Regards, >>>>>> Florin >>>>>> >>>>>>> On Mar 20, 2023, at 1:58 AM, Zhang Dongya <fortitude.zh...@gmail.com >>>>>>> <mailto:fortitude.zh...@gmail.com>> wrote: >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> It seems the issue occurs when there are disconnect called because our >>>>>>> network can't guarantee a tcp can't be reset even when 3 ways handshake >>>>>>> is completed (firewall issue :( ). >>>>>>> >>>>>>> When we find the app layer timeout, we will first disconnect (because >>>>>>> we record the session handle, this session might be a half open >>>>>>> session), does vnet session layer guarantee that if we reconnect from >>>>>>> master thread when the half open session still not be released yet (due >>>>>>> to asynchronous logic) that the reconnect fail? if then we can retry >>>>>>> connect later. >>>>>>> >>>>>>> I prefer to not registered half open callback because I think it make >>>>>>> app complicated from a TCP programming prospective. >>>>>>> >>>>>>> For your patch, I think it should be work because I can't delete the >>>>>>> half open session immediately because there is worker configured, so >>>>>>> the half open will be removed from bihash when syn retrans timeout. I >>>>>>> have merged the patch and will provide feedback later. >>>>>>> >>>>>>> Florin Coras <fcoras.li...@gmail.com <mailto:fcoras.li...@gmail.com>> >>>>>>> 于2023年3月20日周一 13:09写道： >>>>>>>> Hi, >>>>>>>> >>>>>>>> Inline. >>>>>>>> >>>>>>>>> On Mar 19, 2023, at 6:47 PM, Zhang Dongya <fortitude.zh...@gmail.com >>>>>>>>> <mailto:fortitude.zh...@gmail.com>> wrote: >>>>>>>>> >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> It can be aborted both in established state or half open state >>>>>>>>> because I will do timeout in our app layer. >>>>>>>> >>>>>>>> [fc] Okay! Is the issue present irrespective of the state of the >>>>>>>> session or does it happen only after a disconnect in hanf-open state? >>>>>>>> More lower. >>>>>>>> >>>>>>>>> >>>>>>>>> Regarding your question, >>>>>>>>> >>>>>>>>> - Yes we add a builtin in app relys on C apis that mainly use >>>>>>>>> vnet_connect/disconnect to connect or disconnect session. >>>>>>>> >>>>>>>> [fc] Understood >>>>>>>> >>>>>>>>> - We call these api in a vpp ctrl process which should be running on >>>>>>>>> the master thread, we never do session setup/teardown on worker >>>>>>>>> thread. (the environment that found this issue is configured with 1 >>>>>>>>> master + 1 worker setup.) >>>>>>>> >>>>>>>> [fc] With vpp latest it’s possible to connect from first workers. It’s >>>>>>>> an optimization meant to avoid 1) worker barrier on syns and 2) >>>>>>>> entering poll mode on main (consume less cpu) >>>>>>>> >>>>>>>>> - We started to develop the app using 22.06 and I keep to merge >>>>>>>>> upstream changes to latest vpp by cherry-picking. The reason for line >>>>>>>>> mismatch is that I added some comment to the session layer code, it >>>>>>>>> should be equal to the master branch now. >>>>>>>> >>>>>>>> [fc] Ack >>>>>>>> >>>>>>>>> >>>>>>>>> When reading the code I understand that we mainly want to cleanup >>>>>>>>> half open from bihash in session_stream_connect_notify, however, in >>>>>>>>> syn-sent state if I choose to close the session, the session might be >>>>>>>>> closed by my app due to session setup timeout (in second scale), in >>>>>>>>> that case, session will be marked as half_open_done and half open >>>>>>>>> session will be freed shortly in the ctrl thread (the 1st worker?). >>>>>>>> >>>>>>>> [fc] Actually, this might be the issue. We did start to provide a >>>>>>>> half-open session handle to apps which if closed does clean up the >>>>>>>> session but apparently it is missing the cleanup of the session lookup >>>>>>>> table. Could you try this patch [1]? It might need additional work. >>>>>>>> >>>>>>>> Having said that, forcing a close/cleanup will not free the port >>>>>>>> synchronously. So, if you’re using fixed ports, you’ll have to wait >>>>>>>> for the half-open cleanup notification. >>>>>>>> >>>>>>>>> >>>>>>>>> Should I also registered half open callback or there are some other >>>>>>>>> reason that lead to this failure? >>>>>>>>> >>>>>>>> >>>>>>>> [fc] Yes, see above. >>>>>>>> >>>>>>>> Regards, >>>>>>>> Florin >>>>>>>> >>>>>>>> [1] https://gerrit.fd.io/r/c/vpp/+/38526 >>>>>>>> >>>>>>>>> >>>>>>>>> Florin Coras <fcoras.li...@gmail.com <mailto:fcoras.li...@gmail.com>> >>>>>>>>> 于2023年3月20日周一 06:22写道： >>>>>>>>>> Hi, >>>>>>>>>> >>>>>>>>>> When you abort the connection, is it fully established or half-open? >>>>>>>>>> Half-opens are cleaned up by the owner thread after a timeout, but >>>>>>>>>> the 5-tuple should be assigned to the fully established session by >>>>>>>>>> that point. tcp_half_open_connection_cleanup does not cleanup the >>>>>>>>>> bihash instead session_stream_connect_notify does once tcp connect >>>>>>>>>> returns either success or failure. >>>>>>>>>> >>>>>>>>>> So a few questions: >>>>>>>>>> - is it accurate to assume you have a builtin vpp app and rely only >>>>>>>>>> on C apis to interact with host stack? >>>>>>>>>> - on what thread (main or first worker) do you call vnet_connect? >>>>>>>>>> - what api do you use to close the session? >>>>>>>>>> - what version of vpp is this because lines don’t match vpp latest? >>>>>>>>>> >>>>>>>>>> Regards, >>>>>>>>>> Florin >>>>>>>>>> >>>>>>>>>> > On Mar 19, 2023, at 2:08 AM, Zhang Dongya >>>>>>>>>> > <fortitude.zh...@gmail.com <mailto:fortitude.zh...@gmail.com>> >>>>>>>>>> > wrote: >>>>>>>>>> > >>>>>>>>>> > Hi list, >>>>>>>>>> > >>>>>>>>>> > recently in our application, we constantly triggered such abrt >>>>>>>>>> > issue which make our connectivity interrupt for a while: >>>>>>>>>> > >>>>>>>>>> > Mar 19 16:11:26 ubuntu vnet[2565933]: received signal SIGABRT, PC >>>>>>>>>> > 0x7fefd3b2000b >>>>>>>>>> > Mar 19 16:11:26 ubuntu vnet[2565933]: >>>>>>>>>> > /home/fortitude/glx/vpp/src/vnet/tcp/tcp_input.c:3004 >>>>>>>>>> > (tcp46_input_inline) assertion `tcp_lookup_is_valid (tc0, b[0], >>>>>>>>>> > tcp_buffer_hdr (b[0]))' fails >>>>>>>>>> > >>>>>>>>>> > Our scenario is quite simple, we will make 4 parallel tcp >>>>>>>>>> > connection (use 4 fixed source ports) to a remote vpp stack (fixed >>>>>>>>>> > ip and port), and will do some keepalive in our application layer, >>>>>>>>>> > since we only use the vpp tcp stack to make the middle box happy >>>>>>>>>> > with the connection, we do not use the data transport of tcp >>>>>>>>>> > statck actually. >>>>>>>>>> > >>>>>>>>>> > However, since the network condition is complex, we have to >>>>>>>>>> > always need to abrt the connection and reconnect. >>>>>>>>>> > >>>>>>>>>> > I keep to merge upstream session and tcp fix however the issue >>>>>>>>>> > still not fixed, what I found now it may be in some case >>>>>>>>>> > tcp_half_open_connection_cleanup may not deleted the half open >>>>>>>>>> > session from the lookup table (bihash) and the session index is >>>>>>>>>> > realloced by other connection. >>>>>>>>>> > >>>>>>>>>> > Hope the list can provide some hint about how to overcome this >>>>>>>>>> > issue, thanks a lot. >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>> >>>> >>>> >>>> >>> >> >> >> >> > >
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