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Subject: Re: [PATCH] virtio-net: support the outer source port hash for UDP-encapsulated packets
On Fri, Jul 28, 2023 at 04:46:35PM +0800, Heng Qi wrote: > UDP tunneling protocols usually identify a flow using the outer source UDP > port, which is useful for processing UDP-encapsulated packets, such as > increasing entropy for RSS queue selection or hashing the same flow to the > same receive queue. Therefore, we extend it as a new RSS configuration. > that's not a real motivation is it? it's already included for increasing entropy. the real motivation is ignoring source and destination ip because they can change if tunneling gateway changes, right? > Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> > Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > --- > device-types/net/description.tex | 49 ++++++++++++++++++++++++- > device-types/net/device-conformance.tex | 1 + > 2 files changed, 48 insertions(+), 2 deletions(-) > > diff --git a/device-types/net/description.tex b/device-types/net/description.tex > index 76585b0..366775a 100644 > --- a/device-types/net/description.tex > +++ b/device-types/net/description.tex > @@ -88,6 +88,9 @@ \subsection{Feature bits}\label{sec:Device Types / Network Device / Feature bits > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control > channel. > > +\item[VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT(50)] Device supports outer source port hash > + for UDP-encapsulated packets. > + > \item[VIRTIO_NET_F_HASH_TUNNEL(51)] Device supports inner header hash for encapsulated packets. > > \item[VIRTIO_NET_F_VQ_NOTF_COAL(52)] Device supports virtqueue notification coalescing. > @@ -150,6 +153,7 @@ \subsubsection{Feature bit requirements}\label{sec:Device Types / Network Device > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ. > \item[VIRTIO_NET_F_VQ_NOTF_COAL] Requires VIRTIO_NET_F_CTRL_VQ. > \item[VIRTIO_NET_F_HASH_TUNNEL] Requires VIRTIO_NET_F_CTRL_VQ along with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > +\item[VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT] Requires VIRTIO_NET_F_CTRL_VQ along with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > \end{description} > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits} > @@ -927,11 +931,29 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > #define VIRTIO_NET_HASH_TYPE_UDP_EX (1 << 8) > \end{lstlisting} > > +A UDP-encapsulated packet uses UDP as the transport protocol in the outer header > +\ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / Encapsulated packet}. > +UDP tunneling protocols usually use the outer source UDP port to identify a specific flow. > +The hash calculated over the outer source UDP port > can thus be used by the device to queue these different flows what does this "can be used" mean here is unclear. > +on different receive queues or queue the same specific flow on the same receive queue. different from what? same as what? > + > +If additionally the feature VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT was negotiated, > +the following hash types are applicable for UDP-encapsulated packets: > +\begin{lstlisting} > +#define VIRTIO_NET_HASH_TYPE_UDPv4_TUNNEL_SRCPORT (1 << 9) > +#define VIRTIO_NET_HASH_TYPE_UDPv6_TUNNEL_SRCPORT (1 << 10) > +\end{lstlisting} > + > \subparagraph{IPv4 packets} > \label{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets / IPv4 packets} > The device calculates the hash on IPv4 packets according to 'Enabled hash types' bitmask as follows: > \begin{itemize} > -\item If VIRTIO_NET_HASH_TYPE_TCPv4 is set and the packet has > +\item If additionally VIRTIO_NET_HASH_TYPE_UDPv4_TUNNEL_SRCPORT is set and a received encapsulated what makes the packet "encapsulated" here is unclear. > +packet has an outer UDPv4 header, the hash is calculated over the following fields: > +\begin{itemize} > +\item Outer source UDP port > +\end{itemize} > +\item Else if VIRTIO_NET_HASH_TYPE_TCPv4 is set and the packet has > a TCP header, the hash is calculated over the following fields: > \begin{itemize} > \item Source IP address > @@ -961,7 +983,12 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > The device calculates the hash on IPv6 packets without extension > headers according to 'Enabled hash types' bitmask as follows: > \begin{itemize} > -\item If VIRTIO_NET_HASH_TYPE_TCPv6 is set and the packet has > +\item If additionally VIRTIO_NET_HASH_TYPE_UDPv6_TUNNEL_SRCPORT is set and a received encapsulated > +packet has an outer UDPv6 header, the hash is calculated over the following fields: > +\begin{itemize} > +\item Outer source UDP port > +\end{itemize} > +\item Else if VIRTIO_NET_HASH_TYPE_TCPv6 is set and the packet has > a TCPv6 header, the hash is calculated over the following fields: > \begin{itemize} > \item Source IPv6 address > @@ -991,6 +1018,11 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > The device calculates the hash on IPv6 packets with extension > headers according to 'Enabled hash types' bitmask as follows: > \begin{itemize} > +\item If additionally VIRTIO_NET_HASH_TYPE_UDPv6_TUNNEL_SRCPORT is set and a received encapsulated > +packet has an outer UDPv6 header, the hash is calculated over the following fields: > +\begin{itemize} > +\item Outer source UDP port > +\end{itemize} > \item If VIRTIO_NET_HASH_TYPE_TCP_EX is set and the packet > has a TCPv6 header, the hash is calculated over the following fields: > \begin{itemize} > @@ -1139,8 +1171,21 @@ \subsubsection{Processing of Incoming Packets}\label{sec:Device Types / Network > #define VIRTIO_NET_HASH_REPORT_IPv6_EX 7 > #define VIRTIO_NET_HASH_REPORT_TCPv6_EX 8 > #define VIRTIO_NET_HASH_REPORT_UDPv6_EX 9 > +#define VIRTIO_NET_HASH_REPORT_UDPv4_TUNNEL_SRCPORT 10 /* Only if additionally VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT was negotiated */ > +#define VIRTIO_NET_HASH_REPORT_UDPv6_TUNNEL_SRCPORT 11 /* Only if additionally VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT was negotiated */ > \end{lstlisting} > > +\devicenormative{\subparagraph}{Outer Source UDP Port}{Device Types / Network Device / Device Operation / Outer Source UDP Port} > + > +When all the following cases occur: > +\begin{itemize} > +\item Both VIRTIO_NET_F_HASH_UDP_TUNNEL_SRCPORT and VIRTIO_NET_F_HASH_TUNNEL are negotiated. > +\item A received UDP-encapsulated packet's outer header matches one of the encapsulation types enabled in \field{enabled_tunnel_types}. > +\item VIRTIO_NET_HASH_TYPE_UDPv4_TUNNEL_SRCPORT is set in \field{hash_types} and a received encapsulated packet has an outer UDPv4 header or > + VIRTIO_NET_HASH_TYPE_UDPv6_TUNNEL_SRCPORT is set in \field{hash_types} and a received encapsulated packet has an outer UDPv6 header. > +\end{itemize} > +the device MUST calculate the hash over the inner header rather than the outer source UDP port. > + > \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 > diff --git a/device-types/net/device-conformance.tex b/device-types/net/device-conformance.tex > index f88f48b..4fd036b 100644 > --- a/device-types/net/device-conformance.tex > +++ b/device-types/net/device-conformance.tex > @@ -7,6 +7,7 @@ > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Packet Transmission} > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Setting Up Receive Buffers} > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Processing of Incoming Packets} > +\item \ref{devicenormative:Device Types / Network Device / Device Operation / Outer Source UDP Port} > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering} > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering} > \item \ref{devicenormative:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering} > -- > 2.19.1.6.gb485710b
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