[virtio-dev] Re: [PATCH 2/2] virtio_net: support inner header hash for GRE-encapsulated packets

[Jason Wang <jasowang@redhat.com>]

On Wed, Nov 9, 2022 at 7:33 PM Heng Qi <hengqi@linux.alibaba.com> wrote:
>
> From: Heng Qi <henqqi@linux.alibaba.com>
>
> When VIRTIO_NET_F_RSS is negotiated and the tunnel is used to
> encapsulate the packets, the hash calculated using the outer header
> of the receive packets is always fixed for the same flow packets,
> i.e. they will be steered to the same receive queue.
>
> We add a VIRTIO_NET_HASH_TYPE_GRE_INNER bitmask in \field{hash_types},
> which instructs the device to calculate the hash using the inner headers
> of GRE-encapsulated packets.
>
> Signed-off-by: Heng Qi <henqqi@linux.alibaba.com>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>  content.tex | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 116 insertions(+)
>
> diff --git a/content.tex b/content.tex
> index 6fabf1d..319d401 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -3883,6 +3883,10 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network
>  #define VIRTIO_NET_HASH_TYPE_TCP_EX            (1 << 7)
>  #define VIRTIO_NET_HASH_TYPE_UDP_EX            (1 << 8)
>  \end{lstlisting}
> +Hash types applicable to inner payloads of GRE-encapsulated packets
> +\begin{lstlisting}
> +#define VIRTIO_NET_HASH_TYPE_GRE_INNER         (1 << 9)
> +\end{lstlisting}
>
>  \subparagraph{IPv4 packets}
>  \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / IPv4 packets}
> @@ -3975,6 +3979,114 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network
>  (see \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / IPv6 packets without extension header}).
>  \end{itemize}
>
> +\subparagraph{Inner payloads of GRE-encapsulated packets}
> +\label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Inner payloads of GRE-encapsulated packets}}
> +VIRTIO_NET_HASH_TYPE_GRE_INNER bit MUST be set at the same time as one of
> +the bits between VIRTIO_NET_HASH_TYPE_IPv4 and VIRTIO_NET_HASH_TYPE_UDP_EX.

"MUST" keyword must belong to the normative section.

> +
> +The device calculates the hash on GRE-encapsulated packets whose inner payloads
> +are IPv4 packets according to 'Enabled hash types' bitmasks as follows:
> +\begin{itemize}
> +  \item If both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_TCPv4 bits
> +      are set, and the GRE-encapsulated packet has an inner TCPv4 header in its
> +      payload, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IP address
> +      \item Inner destination IP address
> +      \item Inner source TCP port
> +      \item Inner destination TCP port
> +    \end{itemsize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_UDPv4
> +      bits are set, and the GRE-encapsulated packet has an inner UDPv4 header in
> +      its payload, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IP address
> +      \item Inner destination IP address
> +      \item Inner source UDP port
> +      \item Inner destination UDP port
> +    \end{itemize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_IPv4
> +      bits are set, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IP address
> +      \item Inner destination IP address
> +    \end{itemsize}
> +  \item Else the device does not calculate the hash
> +\end{itemize}
> +
> +The device calculates the hash on GRE-encapsulated packets whose inner payloads
> +are IPv6 packets without extension headers according to 'Enabled hash types'
> +bitmasks as follows:
> +\begin{itemsize}
> +  \item If both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_TCPv6
> +      bits are set, and the GRE-encapsulated packet has an inner TCPv6 header in
> +      its payload, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IPv6 address
> +      \item Inner destination IPv6 address
> +      \item Inner source TCP port
> +      \item Inner destination TCP port
> +    \end{itemsize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_UDPv6
> +      bits are set, and the GRE-encapsulated packet has an inner UDPv6 header in
> +      its payload, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IPv6 address
> +      \item Inner destination IPv6 address
> +      \item Inner source UDP port
> +      \item Inner destination UDP port
> +    \end{itemize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_IPv6
> +      bits are set, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Inner source IPv6 address
> +      \item Inner destination IPv6 address
> +    \end{itemsize}
> +  \item Else the device does not calculate the hash
> +\end{itemize}
> +
> +The device calculates the hash on GRE-encapsulated packets whose inner payloads
> +are IPv6 packets with extension headers according to 'Enabled hash types'
> +bitmasks as follows:
> +\begin{itemsize}
> +  \item If both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_TCP_EX
> +      bits are set, and the GRE-encapsulated packet has an inner TCPv6 header in
> +      its payload, the hash is calculated over the following fields:
> +    \begin{itemize}
> +      \item Home address from the home address option in the IPv6 destination options

Is this inner or outer?

Thanks

> +          header. If the extension header is not present, use the Source IPv6 address.
> +      \item IPv6 address that is contained in the Routing-Header-Type-2 from the
> +          associated extension header. If the extension header is not present, use
> +          the Destination IPv6 address.
> +      \item Source TCP port
> +      \item Destination TCP port
> +    \end{itemize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_UDP_EX
> +  bits are set, and the GRE-encapsulated packet has an inner UDPv6 header in its
> +  payload, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Home address from the home address option in the IPv6 destination options
> +          header. If the extension header is not present, use the Source IPv6 address.
> +      \item IPv6 address that is contained in the Routing-Header-Type-2 from the
> +          associated extension header. If the extension header is not present, use the
> +          Destination IPv6 address.
> +      \item Source UDP port
> +      \item Destination UDP port
> +    \end{itemize}
> +  \item Else if both VIRTIO_NET_HASH_TYPE_GRE_INNER and VIRTIO_NET_HASH_TYPE_IP_EX
> +      bits are set, the hash is calculated over the following fields:
> +    \begin{itemsize}
> +      \item Home address from the home address option in the IPv6 destination options
> +          header. If the extension header is not present, use the Source IPv6 address.
> +      \item IPv6 address that is contained in the Routing-Header-Type-2 from the
> +          associated extension header. If the extension header is not present, use the
> +          Destination IPv6 address.
> +    \end{itemize}
> +  \item Else skip IPv6 extension headers and calculate the hash as defined for
> +      a GRE-encapsulated packet whose inner payload is an IPv6 packet without
> +      extension headers
> +\end{itemsize}
> +
>  \paragraph{Hash reporting for incoming packets}
>  \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash reporting for incoming packets}
>
> @@ -4005,6 +4117,10 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network
>  #define VIRTIO_NET_HASH_REPORT_UDPv6_EX        9
>  \end{lstlisting}
>
> +VIRTIO_NET_HASH_TYPE_GRE_INNER bit is not included in \field{hash_report},
> +it just indicates that the hash is calculated using the inner header inside
> +the GRE-encapsulated packet.
> +
>  \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue}
>
>  The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
> --
> 2.19.1.6.gb485710b
>


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