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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Hi All,<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I have written a kernel module using netfilter framework. In my code I’ll do some modifications to the header & payload parts of UDP packet in pre & post hooks.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>After modifying the udp packet, I’m computing ip & udp checksum. This computation is consuming some cpu cycles.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Now, I want to offload this computation to the Ethernet device. For this I have commented the checksum computation in my code and enabled the checksum offload parameters of my Ethernet device.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>While testing, I found that kernel is dropping the packets because of invalid checksums for ip & udp packets.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I have few doubts regarding checksum offload<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Shall I need to do anything in my kernel code.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I’m using the below command to enable checksum offload<o:p></o:p></span></p><p class=MsoListParagraph><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>ethtool –K eth0 rx on tx on<o:p></o:p></span></p><p class=MsoListParagraph><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>Is there anything I need to do apart from this ?<o:p></o:p></span></p><p class=MsoListParagraph><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'>I’m testing my kernel code in kernel-2.6.32.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#17365D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#002060'>Thanks & Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Trebuchet MS","sans-serif";color:#002060'>Murali Annamneni</span><span style='color:#17365D'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div><span style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: gray; FONT-SIZE: 7.5pt; mso-fareast-font-family: 'Times New Roman'">
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