Re: [PATCH] openvswitch: supply a dummy err_handler of gre_cisco_protocol to prevent kernel crash

From: wei zhang
Date: Tue Apr 01 2014 - 20:39:08 EST


AtÂ2014-04-02Â02:27:56,"JesseÂGross"Â<jesse@xxxxxxxxxx>Âwrote:
>OnÂTue,ÂAprÂ1,Â2014ÂatÂ8:24ÂAM,ÂweiÂzhangÂ<asuka.com@xxxxxxx>Âwrote:
>>ÂAtÂ2014-04-01Â08:49:53,"JesseÂGross"Â<jesse@xxxxxxxxxx>Âwrote:
>>>OnÂSun,ÂMarÂ30,Â2014ÂatÂ5:12ÂAM,ÂweiÂzhangÂ<asuka.com@xxxxxxx>Âwrote:
>>>>ÂAtÂ2014-03-29Â06:02:25,"JesseÂGross"Â<jesse@xxxxxxxxxx>Âwrote:
>>
>>>>ÂMaybeÂIÂmisunderstandÂsomething?ÂIÂthinkÂifÂweÂdiscardÂallÂpacketÂpassÂtoÂus
>>>>ÂwhenÂweÂuseÂgreÂvport,ÂnewÂgre_cisco_protocolÂwhichÂhasÂlowerÂpriorityÂcould
>>>>ÂnotÂseeÂtheÂpacketÂintendedÂtoÂit.
>>>
>>>That'sÂtrueÂbutÂinÂthisÂcaseÂitÂwouldÂalsoÂnotÂseeÂanyÂdataÂpackets,
>>>soÂIÂdon'tÂthinkÂthatÂsituationÂwouldÂworkÂwellÂanyways.
>>>
>>>>ÂIÂcheckedÂtheÂimplementationÂofÂtheÂipgre_err(),ÂwhichÂhasÂbeÂcalledÂbefore
>>>>ÂtheÂerr_handlerÂofÂgreÂvport.ÂItÂuseÂtheÂtheÂ(localÂaddress,ÂremoteÂaddress,Âkey)
>>>>ÂtoÂdistinguishÂtheÂpacketÂwhichÂisÂrealyÂintendedÂtoÂit,ÂalthoughÂitÂcouldÂnot
>>>>ÂalwaysÂgetÂtheÂkeyÂfromÂtheÂicmpÂpacket.ÂShouldÂweÂdoÂasÂtheÂsameÂasÂit?
>>>>ÂI'mÂnotÂsureÂthisÂisÂfeasible,ÂanyÂadviceÂisÂappreciate.
>>>
>>>OVSÂdoesÂflowÂbasedÂmatchingÂratherÂthanÂusingÂaÂstaticÂsetÂof
>>>configurationÂparameters,ÂsoÂeverythingÂ"matches"ÂinÂsomeÂway
>>>(althoughÂtheÂresultÂmightÂbeÂtoÂdrop).
>>
>>ÂSoÂtheÂflowÂbasedÂmatchÂcouldÂdynamicallyÂdetermineÂbyÂtheÂovsÂdaemon,ÂweÂcould
>>ÂnotÂfindÂoutÂtheÂbelongingÂofÂtheÂpacketÂasÂfarÂasÂweÂcallÂovs_dp_upcall(),Âisn'tÂit?
>
>That'sÂrightÂ-ÂandÂsinceÂtheÂOVSÂflowÂtableÂalwaysÂhasÂaÂdefault
>behaviorÂ(evenÂifÂitÂisÂdropÂorÂsendÂtoÂcontroller)Âthere'sÂneverÂa
>packetÂthatÂisn'tÂconsideredÂtoÂbeÂdestinedÂtoÂOVSÂonceÂitÂis
>received.
>
>IfÂthisÂmakesÂsenseÂtoÂyou,ÂwouldÂyouÂmindÂsubmittingÂtheÂpatchÂyou
>hadÂearlierÂformallyÂwithÂaÂcommitÂmessageÂandÂsignedÂoffÂbyÂline?

Sure, thank you again as it's my first time to send patch to the kernel, your patient and kind
help give me confidence to do it :)

Regards,
Wei ZhangN‹§²æ¸›yú²X¬¶ÇvØ–)Þ{.nlj·¥Š{±‘êX§¶›¡Ü}©ž²ÆzÚj:+v‰¨¾«‘êZ+€Êzf£¢·hšˆ§~†­†Ûÿû®w¥¢¸?™¨è&¢)ßf”ùy§m…á«a¶Úÿ 0¶ìå