[vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Hi folks, I was going through ip6 code, and observed VPP skips calculating UDP checksum for packets with explicit zero checksum, and process the packet "normally". (This, after disabling HW checksum offload) But, as per RFC-2460, "*IPv6 receivers must discard UDP packets containing a zero checksum, and should log **the error*." Is this expected behavior from VPP? Or will it be modified to be RFC compliant? Thanks Shiva -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15009): https://lists.fd.io/g/vpp-dev/message/15009 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Hi Shiva, > I was going through ip6 code, and observed VPP skips calculating UDP checksum > for packets with explicit zero checksum, and process the packet "normally". > (This, after disabling HW checksum offload) > > But, as per RFC-2460, > "IPv6 receivers must discard UDP packets containing a zero checksum, and > should log the error." > > Is this expected behavior from VPP? Or will it be modified to be RFC > compliant? The IPv6 UDP checksum behaviour was updated with RFC6935 and RFC6936. In VPP we basically leave it up to the application to decide if it requires the UDP checksum or not. Best regards, Ole -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15010): https://lists.fd.io/g/vpp-dev/message/15010 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Hi Ole, Thank you for your reply. I am not using any tunneling protocol in my case(IPV6+UDP+ payload) RFC 6935 says, "The update is specified for use by a tunnel protocol that transports packets that are themselves protected by a checksum." >>> In VPP we basically leave it up to the application to decide if it requires the UDP checksum or not. So, will VPP maintain the same behavior even for non-tunneled IPV6 UDP datagrams? Thanks Shiva On Thu, Jan 2, 2020 at 4:03 PM wrote: > Hi Shiva, > > > I was going through ip6 code, and observed VPP skips calculating UDP > checksum for packets with explicit zero checksum, and process the packet > "normally". (This, after disabling HW checksum offload) > > > > But, as per RFC-2460, > > "IPv6 receivers must discard UDP packets containing a zero checksum, and > should log the error." > > > > Is this expected behavior from VPP? Or will it be modified to be RFC > compliant? > > The IPv6 UDP checksum behaviour was updated with RFC6935 and RFC6936. > In VPP we basically leave it up to the application to decide if it > requires the UDP checksum or not. > > Best regards, > Ole > > -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15011): https://lists.fd.io/g/vpp-dev/message/15011 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Shiva, > I am not using any tunneling protocol in my case(IPV6+UDP+ payload) > > RFC 6935 says, > "The update is specified for use by a tunnel protocol that transports > packets that are themselves protected by a checksum." > > >>> In VPP we basically leave it up to the application to decide if it > >>> requires the UDP checksum or not. > So, will VPP maintain the same behavior even for non-tunneled IPV6 UDP > datagrams? Which application of UDP are you specifically referring to? Cheers, Ole-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15012): https://lists.fd.io/g/vpp-dev/message/15012 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Forgot to add "reply-all", My apologies. Ole, >>> Right, so if you do not want to accept UDP zero checksum packets in your application, add the check in your code. I Agree. Just curious to know the design choice. So, by design, VPP hands over the UDP packet to "registered node" irrespective of the payload. Is that correct? Thanks Shiva On Thu, Jan 2, 2020 at 5:12 PM wrote: > Shiva, > > > I am running a custom VPP node that registers to a specific UDP port > (network is using IP6 protocol). > > Right, so if you do not want to accept UDP zero checksum packets in your > application, add the check in your code. > > Best regards, > Ole > > -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15017): https://lists.fd.io/g/vpp-dev/message/15017 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Hi Shiva, > Forgot to add "reply-all", My apologies. > > Ole, > >>> Right, so if you do not want to accept UDP zero checksum packets in your > >>> application, add the check in your code. > I Agree. Just curious to know the design choice. > > So, by design, VPP hands over the UDP packet to "registered node" > irrespective of the payload. > Is that correct? Yes that's correct. The UDP dispatcher can obviously not know anything about the UDP payload. There is very little to UDP. The VPP local IP handling only provides a demux point based on the destination port. And IP reassembly. The rest is up to the UDP application. https://git.fd.io/vpp/tree/src/vnet/udp/udp_local.c#n57 Best regards, Ole-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15018): https://lists.fd.io/g/vpp-dev/message/15018 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
Re: [vpp-dev] IPv6 UDP Datagrams with Zero Checksum- RFC complaint ?
Ole, Got it. I did go through udp local code previously and found we are doing only UDP dear port based and error handling in the node. Anyway , Thankyou so much for responding patiently. Thanks Shiva On Thu, 2 Jan 2020 at 18:11, wrote: > Hi Shiva, > > > Forgot to add "reply-all", My apologies. > > > > Ole, > > >>> Right, so if you do not want to accept UDP zero checksum packets in > your application, add the check in your code. > > I Agree. Just curious to know the design choice. > > > > So, by design, VPP hands over the UDP packet to "registered node" > irrespective of the payload. > > Is that correct? > > Yes that's correct. The UDP dispatcher can obviously not know anything > about the UDP payload. > There is very little to UDP. The VPP local IP handling only provides a > demux point based on the destination port. > And IP reassembly. > The rest is up to the UDP application. > > https://git.fd.io/vpp/tree/src/vnet/udp/udp_local.c#n57 > > Best regards, > Ole -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#15019): https://lists.fd.io/g/vpp-dev/message/15019 Mute This Topic: https://lists.fd.io/mt/69364719/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
