diff options
| -rw-r--r-- | content.tex | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/content.tex b/content.tex index 979dbfc..15a4823 100644 --- a/content.tex +++ b/content.tex @@ -2731,6 +2731,9 @@ features. \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control channel. +\item[VIRTIO_NET_F_RSC_EXT(38)] Device can process duplicated ACKs + and report number of coalesced segments and duplicated ACKs + \item[VIRTIO_NET_F_STANDBY(62)] Device may act as a standby for a primary device with the same MAC address. \end{description} @@ -2756,6 +2759,7 @@ Some networking feature bits require other networking feature bits \item[VIRTIO_NET_F_GUEST_ANNOUNCE] Requires VIRTIO_NET_F_CTRL_VQ. \item[VIRTIO_NET_F_MQ] Requires VIRTIO_NET_F_CTRL_VQ. \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ. +\item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or VIRTIO_NET_F_HOST_TSO6. \end{description} \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits} @@ -2929,6 +2933,7 @@ itself is preceded by a header: struct virtio_net_hdr { #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 #define VIRTIO_NET_HDR_F_DATA_VALID 2 +#define VIRTIO_NET_HDR_F_RSC_INFO 4 u8 flags; #define VIRTIO_NET_HDR_GSO_NONE 0 #define VIRTIO_NET_HDR_GSO_TCPV4 1 @@ -3092,8 +3097,8 @@ been negotiated, the driver SHOULD set \field{hdr_len} to a value not less than the length of the headers, including the transport header. -The driver MUST NOT set the VIRTIO_NET_HDR_F_DATA_VALID bit in -\field{flags}. +The driver MUST NOT set the VIRTIO_NET_HDR_F_DATA_VALID and +VIRTIO_NET_HDR_F_RSC_INFO bits in \field{flags}. \devicenormative{\paragraph}{Packet Transmission}{Device Types / Network Device / Device Operation / Packet Transmission} The device MUST ignore \field{flag} bits that it does not recognize. @@ -3209,18 +3214,25 @@ transmit segmentation offloading and ECN features, as described in \ref{sec:Device Types / Network Device / Device Operation / Packet Transmission}: \begin{enumerate} +\item If the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options were + negotiated, then \field{gso_type} MAY be something other than + VIRTIO_NET_HDR_GSO_NONE, and \field{gso_size} field indicates the + desired MSS (see Packet Transmission point 2). +\item If the VIRTIO_NET_F_RSC_EXT option was negotiated (this + implies one of VIRTIO_NET_F_GUEST_TSO4, TSO6), the + device processes also duplicated ACK segments, reports + number of coalesced TCP segments in \field{csum_start} field and + number of duplicated ACK segments in \field{csum_offset} field + and sets bit VIRTIO_NET_HDR_F_RSC_INFO in \field{flags}. \item If the VIRTIO_NET_F_GUEST_CSUM feature was negotiated, the VIRTIO_NET_HDR_F_NEEDS_CSUM bit in \field{flags} can be set: if so, the packet checksum at offset \field{csum_offset} from \field{csum_start} and any preceding checksums have been validated. The checksum on the packet is incomplete and - \field{csum_start} and \field{csum_offset} indicate how to calculate - it (see Packet Transmission point 1). + if bit VIRTIO_NET_HDR_F_RSC_INFO is not set in \field{flags}, + then \field{csum_start} and \field{csum_offset} indicate how to calculate it + (see Packet Transmission point 1). -\item If the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options were - negotiated, then \field{gso_type} MAY be something other than - VIRTIO_NET_HDR_GSO_NONE, and \field{gso_size} field indicates the - desired MSS (see Packet Transmission point 2). \end{enumerate} \devicenormative{\paragraph}{Processing of Incoming Packets}{Device Types / Network Device / Device Operation / Processing of Incoming Packets} @@ -3285,6 +3297,13 @@ VIRTIO_NET_HDR_GSO_NONE. If \field{gso_type} differs from VIRTIO_NET_HDR_GSO_NONE, then the device MUST also set the VIRTIO_NET_HDR_F_NEEDS_CSUM bit in \field{flags} MUST set \field{gso_size} to indicate the desired MSS. +If VIRTIO_NET_F_RSC_EXT was negotiated, the device MUST also +set VIRTIO_NET_HDR_F_RSC_INFO bit in \field{flags}, +set \field{csum_start} to number of coalesced TCP segments and +set \field{csum_offset} to number of received duplicated ACK segments. + +If VIRTIO_NET_F_RSC_EXT was not negotiated, the device MUST +not set VIRTIO_NET_HDR_F_RSC_INFO bit in \field{flags}. If one of the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options have been negotiated, the device SHOULD set \field{hdr_len} to a value @@ -3303,7 +3322,8 @@ Processing of Incoming Packets} The driver MUST ignore \field{flag} bits that it does not recognize. -If VIRTIO_NET_HDR_F_NEEDS_CSUM bit in \field{flags} is not set, the +If VIRTIO_NET_HDR_F_NEEDS_CSUM bit in \field{flags} is not set or +if VIRTIO_NET_HDR_F_RSC_INFO bit \field{flags} is set, the driver MUST NOT use the \field{csum_start} and \field{csum_offset}. If one of the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options have |