941 lines
34 KiB
C
941 lines
34 KiB
C
/* SPDX-License-Identifier: MIT */
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/******************************************************************************
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* xen_netif.h
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*
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* Unified network-device I/O interface for Xen guest OSes.
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*
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* Copyright (c) 2003-2004, Keir Fraser
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*/
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#ifndef __XEN_PUBLIC_IO_XEN_NETIF_H__
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#define __XEN_PUBLIC_IO_XEN_NETIF_H__
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#include "ring.h"
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#include "../grant_table.h"
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/*
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* Older implementation of Xen network frontend / backend has an
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* implicit dependency on the MAX_SKB_FRAGS as the maximum number of
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* ring slots a skb can use. Netfront / netback may not work as
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* expected when frontend and backend have different MAX_SKB_FRAGS.
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*
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* A better approach is to add mechanism for netfront / netback to
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* negotiate this value. However we cannot fix all possible
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* frontends, so we need to define a value which states the minimum
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* slots backend must support.
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*
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* The minimum value derives from older Linux kernel's MAX_SKB_FRAGS
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* (18), which is proved to work with most frontends. Any new backend
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* which doesn't negotiate with frontend should expect frontend to
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* send a valid packet using slots up to this value.
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*/
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#define XEN_NETIF_NR_SLOTS_MIN 18
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/*
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* Notifications after enqueuing any type of message should be conditional on
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* the appropriate req_event or rsp_event field in the shared ring.
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* If the client sends notification for rx requests then it should specify
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* feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume
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* that it cannot safely queue packets (as it may not be kicked to send them).
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*/
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/*
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* "feature-split-event-channels" is introduced to separate guest TX
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* and RX notification. Backend either doesn't support this feature or
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* advertises it via xenstore as 0 (disabled) or 1 (enabled).
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*
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* To make use of this feature, frontend should allocate two event
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* channels for TX and RX, advertise them to backend as
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* "event-channel-tx" and "event-channel-rx" respectively. If frontend
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* doesn't want to use this feature, it just writes "event-channel"
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* node as before.
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*/
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/*
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* Multiple transmit and receive queues:
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* If supported, the backend will write the key "multi-queue-max-queues" to
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* the directory for that vif, and set its value to the maximum supported
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* number of queues.
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* Frontends that are aware of this feature and wish to use it can write the
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* key "multi-queue-num-queues", set to the number they wish to use, which
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* must be greater than zero, and no more than the value reported by the backend
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* in "multi-queue-max-queues".
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*
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* Queues replicate the shared rings and event channels.
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* "feature-split-event-channels" may optionally be used when using
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* multiple queues, but is not mandatory.
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*
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* Each queue consists of one shared ring pair, i.e. there must be the same
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* number of tx and rx rings.
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*
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* For frontends requesting just one queue, the usual event-channel and
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* ring-ref keys are written as before, simplifying the backend processing
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* to avoid distinguishing between a frontend that doesn't understand the
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* multi-queue feature, and one that does, but requested only one queue.
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*
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* Frontends requesting two or more queues must not write the toplevel
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* event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys,
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* instead writing those keys under sub-keys having the name "queue-N" where
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* N is the integer ID of the queue for which those keys belong. Queues
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* are indexed from zero. For example, a frontend with two queues and split
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* event channels must write the following set of queue-related keys:
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*
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* /local/domain/1/device/vif/0/multi-queue-num-queues = "2"
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* /local/domain/1/device/vif/0/queue-0 = ""
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* /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>"
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* /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>"
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* /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>"
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* /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>"
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* /local/domain/1/device/vif/0/queue-1 = ""
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* /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>"
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* /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1"
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* /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>"
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* /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>"
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*
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* If there is any inconsistency in the XenStore data, the backend may
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* choose not to connect any queues, instead treating the request as an
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* error. This includes scenarios where more (or fewer) queues were
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* requested than the frontend provided details for.
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*
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* Mapping of packets to queues is considered to be a function of the
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* transmitting system (backend or frontend) and is not negotiated
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* between the two. Guests are free to transmit packets on any queue
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* they choose, provided it has been set up correctly. Guests must be
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* prepared to receive packets on any queue they have requested be set up.
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*/
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/*
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* "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum
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* offload off or on. If it is missing then the feature is assumed to be on.
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* "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum
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* offload on or off. If it is missing then the feature is assumed to be off.
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*/
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/*
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* "feature-gso-tcpv4" and "feature-gso-tcpv6" advertise the capability to
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* handle large TCP packets (in IPv4 or IPv6 form respectively). Neither
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* frontends nor backends are assumed to be capable unless the flags are
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* present.
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*/
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/*
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* "feature-multicast-control" and "feature-dynamic-multicast-control"
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* advertise the capability to filter ethernet multicast packets in the
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* backend. If the frontend wishes to take advantage of this feature then
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* it may set "request-multicast-control". If the backend only advertises
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* "feature-multicast-control" then "request-multicast-control" must be set
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* before the frontend moves into the connected state. The backend will
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* sample the value on this state transition and any subsequent change in
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* value will have no effect. However, if the backend also advertises
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* "feature-dynamic-multicast-control" then "request-multicast-control"
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* may be set by the frontend at any time. In this case, the backend will
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* watch the value and re-sample on watch events.
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*
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* If the sampled value of "request-multicast-control" is set then the
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* backend transmit side should no longer flood multicast packets to the
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* frontend, it should instead drop any multicast packet that does not
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* match in a filter list.
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* The list is amended by the frontend by sending dummy transmit requests
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* containing XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL} extra-info fragments as
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* specified below.
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* Note that the filter list may be amended even if the sampled value of
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* "request-multicast-control" is not set, however the filter should only
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* be applied if it is set.
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*/
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/*
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* "xdp-headroom" is used to request that extra space is added
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* for XDP processing. The value is measured in bytes and passed by
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* the frontend to be consistent between both ends.
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* If the value is greater than zero that means that
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* an RX response is going to be passed to an XDP program for processing.
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* XEN_NETIF_MAX_XDP_HEADROOM defines the maximum headroom offset in bytes
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*
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* "feature-xdp-headroom" is set to "1" by the netback side like other features
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* so a guest can check if an XDP program can be processed.
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*/
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#define XEN_NETIF_MAX_XDP_HEADROOM 0x7FFF
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/*
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* Control ring
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* ============
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*
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* Some features, such as hashing (detailed below), require a
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* significant amount of out-of-band data to be passed from frontend to
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* backend. Use of xenstore is not suitable for large quantities of data
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* because of quota limitations and so a dedicated 'control ring' is used.
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* The ability of the backend to use a control ring is advertised by
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* setting:
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*
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* /local/domain/X/backend/<domid>/<vif>/feature-ctrl-ring = "1"
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*
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* The frontend provides a control ring to the backend by setting:
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*
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* /local/domain/<domid>/device/vif/<vif>/ctrl-ring-ref = <gref>
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* /local/domain/<domid>/device/vif/<vif>/event-channel-ctrl = <port>
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*
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* where <gref> is the grant reference of the shared page used to
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* implement the control ring and <port> is an event channel to be used
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* as a mailbox interrupt. These keys must be set before the frontend
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* moves into the connected state.
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*
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* The control ring uses a fixed request/response message size and is
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* balanced (i.e. one request to one response), so operationally it is much
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* the same as a transmit or receive ring.
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* Note that there is no requirement that responses are issued in the same
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* order as requests.
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*/
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/*
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* Hash types
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* ==========
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*
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* For the purposes of the definitions below, 'Packet[]' is an array of
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* octets containing an IP packet without options, 'Array[X..Y]' means a
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* sub-array of 'Array' containing bytes X thru Y inclusive, and '+' is
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* used to indicate concatenation of arrays.
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*/
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/*
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* A hash calculated over an IP version 4 header as follows:
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*
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* Buffer[0..8] = Packet[12..15] (source address) +
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* Packet[16..19] (destination address)
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*
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* Result = Hash(Buffer, 8)
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*/
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#define _XEN_NETIF_CTRL_HASH_TYPE_IPV4 0
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#define XEN_NETIF_CTRL_HASH_TYPE_IPV4 \
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(1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4)
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/*
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* A hash calculated over an IP version 4 header and TCP header as
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* follows:
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*
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* Buffer[0..12] = Packet[12..15] (source address) +
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* Packet[16..19] (destination address) +
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* Packet[20..21] (source port) +
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* Packet[22..23] (destination port)
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*
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* Result = Hash(Buffer, 12)
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*/
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#define _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP 1
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#define XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP \
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(1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
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/*
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* A hash calculated over an IP version 6 header as follows:
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*
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* Buffer[0..32] = Packet[8..23] (source address ) +
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* Packet[24..39] (destination address)
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*
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* Result = Hash(Buffer, 32)
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*/
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#define _XEN_NETIF_CTRL_HASH_TYPE_IPV6 2
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#define XEN_NETIF_CTRL_HASH_TYPE_IPV6 \
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(1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6)
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/*
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* A hash calculated over an IP version 6 header and TCP header as
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* follows:
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*
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* Buffer[0..36] = Packet[8..23] (source address) +
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* Packet[24..39] (destination address) +
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* Packet[40..41] (source port) +
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* Packet[42..43] (destination port)
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*
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* Result = Hash(Buffer, 36)
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*/
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#define _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP 3
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#define XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP \
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(1 << _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
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/*
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* Hash algorithms
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* ===============
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*/
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#define XEN_NETIF_CTRL_HASH_ALGORITHM_NONE 0
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/*
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* Toeplitz hash:
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*/
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#define XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ 1
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/*
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* This algorithm uses a 'key' as well as the data buffer itself.
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* (Buffer[] and Key[] are treated as shift-registers where the MSB of
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* Buffer/Key[0] is considered 'left-most' and the LSB of Buffer/Key[N-1]
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* is the 'right-most').
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*
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* Value = 0
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* For number of bits in Buffer[]
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* If (left-most bit of Buffer[] is 1)
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* Value ^= left-most 32 bits of Key[]
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* Key[] << 1
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* Buffer[] << 1
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*
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* The code below is provided for convenience where an operating system
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* does not already provide an implementation.
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*/
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#ifdef XEN_NETIF_DEFINE_TOEPLITZ
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static uint32_t xen_netif_toeplitz_hash(const uint8_t *key,
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unsigned int keylen,
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const uint8_t *buf, unsigned int buflen)
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{
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unsigned int keyi, bufi;
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uint64_t prefix = 0;
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uint64_t hash = 0;
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/* Pre-load prefix with the first 8 bytes of the key */
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for (keyi = 0; keyi < 8; keyi++) {
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prefix <<= 8;
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prefix |= (keyi < keylen) ? key[keyi] : 0;
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}
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for (bufi = 0; bufi < buflen; bufi++) {
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uint8_t byte = buf[bufi];
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unsigned int bit;
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for (bit = 0; bit < 8; bit++) {
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if (byte & 0x80)
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hash ^= prefix;
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prefix <<= 1;
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byte <<= 1;
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}
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/*
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* 'prefix' has now been left-shifted by 8, so
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* OR in the next byte.
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*/
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prefix |= (keyi < keylen) ? key[keyi] : 0;
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keyi++;
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}
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/* The valid part of the hash is in the upper 32 bits. */
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return hash >> 32;
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}
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#endif /* XEN_NETIF_DEFINE_TOEPLITZ */
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/*
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* Control requests (struct xen_netif_ctrl_request)
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* ================================================
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*
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* All requests have the following format:
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*
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* 0 1 2 3 4 5 6 7 octet
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* +-----+-----+-----+-----+-----+-----+-----+-----+
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* | id | type | data[0] |
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* +-----+-----+-----+-----+-----+-----+-----+-----+
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* | data[1] | data[2] |
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* +-----+-----+-----+-----+-----------------------+
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*
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* id: the request identifier, echoed in response.
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* type: the type of request (see below)
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* data[]: any data associated with the request (determined by type)
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*/
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struct xen_netif_ctrl_request {
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uint16_t id;
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uint16_t type;
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#define XEN_NETIF_CTRL_TYPE_INVALID 0
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#define XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS 1
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#define XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS 2
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#define XEN_NETIF_CTRL_TYPE_SET_HASH_KEY 3
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#define XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE 4
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#define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE 5
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#define XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING 6
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#define XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM 7
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uint32_t data[3];
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};
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/*
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* Control responses (struct xen_netif_ctrl_response)
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* ==================================================
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*
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* All responses have the following format:
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*
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* 0 1 2 3 4 5 6 7 octet
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* +-----+-----+-----+-----+-----+-----+-----+-----+
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* | id | type | status |
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* +-----+-----+-----+-----+-----+-----+-----+-----+
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* | data |
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* +-----+-----+-----+-----+
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*
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* id: the corresponding request identifier
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* type: the type of the corresponding request
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* status: the status of request processing
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* data: any data associated with the response (determined by type and
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* status)
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*/
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struct xen_netif_ctrl_response {
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uint16_t id;
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uint16_t type;
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uint32_t status;
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#define XEN_NETIF_CTRL_STATUS_SUCCESS 0
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#define XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED 1
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#define XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER 2
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#define XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW 3
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uint32_t data;
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};
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/*
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* Control messages
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* ================
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*
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* XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
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* --------------------------------------
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*
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* This is sent by the frontend to set the desired hash algorithm.
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*
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* Request:
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*
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* type = XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM
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* data[0] = a XEN_NETIF_CTRL_HASH_ALGORITHM_* value
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* data[1] = 0
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* data[2] = 0
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*
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* Response:
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*
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* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
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* supported
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* XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - The algorithm is not
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* supported
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* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
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*
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* NOTE: Setting data[0] to XEN_NETIF_CTRL_HASH_ALGORITHM_NONE disables
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* hashing and the backend is free to choose how it steers packets
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* to queues (which is the default behaviour).
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*
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* XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
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* ----------------------------------
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*
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* This is sent by the frontend to query the types of hash supported by
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* the backend.
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*
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* Request:
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*
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* type = XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS
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* data[0] = 0
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* data[1] = 0
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* data[2] = 0
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*
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* Response:
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*
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* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
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* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
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* data = supported hash types (if operation was successful)
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*
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* NOTE: A valid hash algorithm must be selected before this operation can
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* succeed.
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*
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* XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
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* ----------------------------------
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*
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* This is sent by the frontend to set the types of hash that the backend
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* should calculate. (See above for hash type definitions).
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* Note that the 'maximal' type of hash should always be chosen. For
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* example, if the frontend sets both IPV4 and IPV4_TCP hash types then
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* the latter hash type should be calculated for any TCP packet and the
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* former only calculated for non-TCP packets.
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*
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* Request:
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*
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* type = XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS
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* data[0] = bitwise OR of XEN_NETIF_CTRL_HASH_TYPE_* values
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* data[1] = 0
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* data[2] = 0
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*
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* Response:
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*
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* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
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* supported
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* XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - One or more flag
|
|
* value is invalid or
|
|
* unsupported
|
|
* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
|
|
* data = 0
|
|
*
|
|
* NOTE: A valid hash algorithm must be selected before this operation can
|
|
* succeed.
|
|
* Also, setting data[0] to zero disables hashing and the backend
|
|
* is free to choose how it steers packets to queues.
|
|
*
|
|
* XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
|
|
* --------------------------------
|
|
*
|
|
* This is sent by the frontend to set the key of the hash if the algorithm
|
|
* requires it. (See hash algorithms above).
|
|
*
|
|
* Request:
|
|
*
|
|
* type = XEN_NETIF_CTRL_TYPE_SET_HASH_KEY
|
|
* data[0] = grant reference of page containing the key (assumed to
|
|
* start at beginning of grant)
|
|
* data[1] = size of key in octets
|
|
* data[2] = 0
|
|
*
|
|
* Response:
|
|
*
|
|
* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
|
|
* supported
|
|
* XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Key size is invalid
|
|
* XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Key size is larger
|
|
* than the backend
|
|
* supports
|
|
* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
|
|
* data = 0
|
|
*
|
|
* NOTE: Any key octets not specified are assumed to be zero (the key
|
|
* is assumed to be empty by default) and specifying a new key
|
|
* invalidates any previous key, hence specifying a key size of
|
|
* zero will clear the key (which ensures that the calculated hash
|
|
* will always be zero).
|
|
* The maximum size of key is algorithm and backend specific, but
|
|
* is also limited by the single grant reference.
|
|
* The grant reference may be read-only and must remain valid until
|
|
* the response has been processed.
|
|
*
|
|
* XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
|
|
* -----------------------------------------
|
|
*
|
|
* This is sent by the frontend to query the maximum size of mapping
|
|
* table supported by the backend. The size is specified in terms of
|
|
* table entries.
|
|
*
|
|
* Request:
|
|
*
|
|
* type = XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE
|
|
* data[0] = 0
|
|
* data[1] = 0
|
|
* data[2] = 0
|
|
*
|
|
* Response:
|
|
*
|
|
* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not supported
|
|
* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
|
|
* data = maximum number of entries allowed in the mapping table
|
|
* (if operation was successful) or zero if a mapping table is
|
|
* not supported (i.e. hash mapping is done only by modular
|
|
* arithmetic).
|
|
*
|
|
* XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
|
|
* -------------------------------------
|
|
*
|
|
* This is sent by the frontend to set the actual size of the mapping
|
|
* table to be used by the backend. The size is specified in terms of
|
|
* table entries.
|
|
* Any previous table is invalidated by this message and any new table
|
|
* is assumed to be zero filled.
|
|
*
|
|
* Request:
|
|
*
|
|
* type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
|
|
* data[0] = number of entries in mapping table
|
|
* data[1] = 0
|
|
* data[2] = 0
|
|
*
|
|
* Response:
|
|
*
|
|
* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
|
|
* supported
|
|
* XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size is invalid
|
|
* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
|
|
* data = 0
|
|
*
|
|
* NOTE: Setting data[0] to 0 means that hash mapping should be done
|
|
* using modular arithmetic.
|
|
*
|
|
* XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
|
|
* ------------------------------------
|
|
*
|
|
* This is sent by the frontend to set the content of the table mapping
|
|
* hash value to queue number. The backend should calculate the hash from
|
|
* the packet header, use it as an index into the table (modulo the size
|
|
* of the table) and then steer the packet to the queue number found at
|
|
* that index.
|
|
*
|
|
* Request:
|
|
*
|
|
* type = XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING
|
|
* data[0] = grant reference of page containing the mapping (sub-)table
|
|
* (assumed to start at beginning of grant)
|
|
* data[1] = size of (sub-)table in entries
|
|
* data[2] = offset, in entries, of sub-table within overall table
|
|
*
|
|
* Response:
|
|
*
|
|
* status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED - Operation not
|
|
* supported
|
|
* XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER - Table size or content
|
|
* is invalid
|
|
* XEN_NETIF_CTRL_STATUS_BUFFER_OVERFLOW - Table size is larger
|
|
* than the backend
|
|
* supports
|
|
* XEN_NETIF_CTRL_STATUS_SUCCESS - Operation successful
|
|
* data = 0
|
|
*
|
|
* NOTE: The overall table has the following format:
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | mapping[0] | mapping[1] |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | . |
|
|
* | . |
|
|
* | . |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | mapping[N-2] | mapping[N-1] |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* where N is specified by a XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE
|
|
* message and each mapping must specifies a queue between 0 and
|
|
* "multi-queue-num-queues" (see above).
|
|
* The backend may support a mapping table larger than can be
|
|
* mapped by a single grant reference. Thus sub-tables within a
|
|
* larger table can be individually set by sending multiple messages
|
|
* with differing offset values. Specifying a new sub-table does not
|
|
* invalidate any table data outside that range.
|
|
* The grant reference may be read-only and must remain valid until
|
|
* the response has been processed.
|
|
*/
|
|
|
|
DEFINE_RING_TYPES(xen_netif_ctrl,
|
|
struct xen_netif_ctrl_request,
|
|
struct xen_netif_ctrl_response);
|
|
|
|
/*
|
|
* Guest transmit
|
|
* ==============
|
|
*
|
|
* This is the 'wire' format for transmit (frontend -> backend) packets:
|
|
*
|
|
* Fragment 1: xen_netif_tx_request_t - flags = XEN_NETTXF_*
|
|
* size = total packet size
|
|
* [Extra 1: xen_netif_extra_info_t] - (only if fragment 1 flags include
|
|
* XEN_NETTXF_extra_info)
|
|
* ...
|
|
* [Extra N: xen_netif_extra_info_t] - (only if extra N-1 flags include
|
|
* XEN_NETIF_EXTRA_MORE)
|
|
* ...
|
|
* Fragment N: xen_netif_tx_request_t - (only if fragment N-1 flags include
|
|
* XEN_NETTXF_more_data - flags on preceding
|
|
* extras are not relevant here)
|
|
* flags = 0
|
|
* size = fragment size
|
|
*
|
|
* NOTE:
|
|
*
|
|
* This format slightly is different from that used for receive
|
|
* (backend -> frontend) packets. Specifically, in a multi-fragment
|
|
* packet the actual size of fragment 1 can only be determined by
|
|
* subtracting the sizes of fragments 2..N from the total packet size.
|
|
*
|
|
* Ring slot size is 12 octets, however not all request/response
|
|
* structs use the full size.
|
|
*
|
|
* tx request data (xen_netif_tx_request_t)
|
|
* ------------------------------------
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | grant ref | offset | flags |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | id | size |
|
|
* +-----+-----+-----+-----+
|
|
*
|
|
* grant ref: Reference to buffer page.
|
|
* offset: Offset within buffer page.
|
|
* flags: XEN_NETTXF_*.
|
|
* id: request identifier, echoed in response.
|
|
* size: packet size in bytes.
|
|
*
|
|
* tx response (xen_netif_tx_response_t)
|
|
* ---------------------------------
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | id | status | unused |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | unused |
|
|
* +-----+-----+-----+-----+
|
|
*
|
|
* id: reflects id in transmit request
|
|
* status: XEN_NETIF_RSP_*
|
|
*
|
|
* Guest receive
|
|
* =============
|
|
*
|
|
* This is the 'wire' format for receive (backend -> frontend) packets:
|
|
*
|
|
* Fragment 1: xen_netif_rx_request_t - flags = XEN_NETRXF_*
|
|
* size = fragment size
|
|
* [Extra 1: xen_netif_extra_info_t] - (only if fragment 1 flags include
|
|
* XEN_NETRXF_extra_info)
|
|
* ...
|
|
* [Extra N: xen_netif_extra_info_t] - (only if extra N-1 flags include
|
|
* XEN_NETIF_EXTRA_MORE)
|
|
* ...
|
|
* Fragment N: xen_netif_rx_request_t - (only if fragment N-1 flags include
|
|
* XEN_NETRXF_more_data - flags on preceding
|
|
* extras are not relevant here)
|
|
* flags = 0
|
|
* size = fragment size
|
|
*
|
|
* NOTE:
|
|
*
|
|
* This format slightly is different from that used for transmit
|
|
* (frontend -> backend) packets. Specifically, in a multi-fragment
|
|
* packet the size of the packet can only be determined by summing the
|
|
* sizes of fragments 1..N.
|
|
*
|
|
* Ring slot size is 8 octets.
|
|
*
|
|
* rx request (xen_netif_rx_request_t)
|
|
* -------------------------------
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | id | pad | gref |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* id: request identifier, echoed in response.
|
|
* gref: reference to incoming granted frame.
|
|
*
|
|
* rx response (xen_netif_rx_response_t)
|
|
* ---------------------------------
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | id | offset | flags | status |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* id: reflects id in receive request
|
|
* offset: offset in page of start of received packet
|
|
* flags: XEN_NETRXF_*
|
|
* status: -ve: XEN_NETIF_RSP_*; +ve: Rx'ed pkt size.
|
|
*
|
|
* NOTE: Historically, to support GSO on the frontend receive side, Linux
|
|
* netfront does not make use of the rx response id (because, as
|
|
* described below, extra info structures overlay the id field).
|
|
* Instead it assumes that responses always appear in the same ring
|
|
* slot as their corresponding request. Thus, to maintain
|
|
* compatibility, backends must make sure this is the case.
|
|
*
|
|
* Extra Info
|
|
* ==========
|
|
*
|
|
* Can be present if initial request or response has NET{T,R}XF_extra_info,
|
|
* or previous extra request has XEN_NETIF_EXTRA_MORE.
|
|
*
|
|
* The struct therefore needs to fit into either a tx or rx slot and
|
|
* is therefore limited to 8 octets.
|
|
*
|
|
* NOTE: Because extra info data overlays the usual request/response
|
|
* structures, there is no id information in the opposite direction.
|
|
* So, if an extra info overlays an rx response the frontend can
|
|
* assume that it is in the same ring slot as the request that was
|
|
* consumed to make the slot available, and the backend must ensure
|
|
* this assumption is true.
|
|
*
|
|
* extra info (xen_netif_extra_info_t)
|
|
* -------------------------------
|
|
*
|
|
* General format:
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* |type |flags| type specific data |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* | padding for tx |
|
|
* +-----+-----+-----+-----+
|
|
*
|
|
* type: XEN_NETIF_EXTRA_TYPE_*
|
|
* flags: XEN_NETIF_EXTRA_FLAG_*
|
|
* padding for tx: present only in the tx case due to 8 octet limit
|
|
* from rx case. Not shown in type specific entries
|
|
* below.
|
|
*
|
|
* XEN_NETIF_EXTRA_TYPE_GSO:
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* |type |flags| size |type | pad | features |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* type: Must be XEN_NETIF_EXTRA_TYPE_GSO
|
|
* flags: XEN_NETIF_EXTRA_FLAG_*
|
|
* size: Maximum payload size of each segment. For example,
|
|
* for TCP this is just the path MSS.
|
|
* type: XEN_NETIF_GSO_TYPE_*: This determines the protocol of
|
|
* the packet and any extra features required to segment the
|
|
* packet properly.
|
|
* features: EN_XEN_NETIF_GSO_FEAT_*: This specifies any extra GSO
|
|
* features required to process this packet, such as ECN
|
|
* support for TCPv4.
|
|
*
|
|
* XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}:
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* |type |flags| addr |
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* type: Must be XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}
|
|
* flags: XEN_NETIF_EXTRA_FLAG_*
|
|
* addr: address to add/remove
|
|
*
|
|
* XEN_NETIF_EXTRA_TYPE_HASH:
|
|
*
|
|
* A backend that supports teoplitz hashing is assumed to accept
|
|
* this type of extra info in transmit packets.
|
|
* A frontend that enables hashing is assumed to accept
|
|
* this type of extra info in receive packets.
|
|
*
|
|
* 0 1 2 3 4 5 6 7 octet
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
* |type |flags|htype| alg |LSB ---- value ---- MSB|
|
|
* +-----+-----+-----+-----+-----+-----+-----+-----+
|
|
*
|
|
* type: Must be XEN_NETIF_EXTRA_TYPE_HASH
|
|
* flags: XEN_NETIF_EXTRA_FLAG_*
|
|
* htype: Hash type (one of _XEN_NETIF_CTRL_HASH_TYPE_* - see above)
|
|
* alg: The algorithm used to calculate the hash (one of
|
|
* XEN_NETIF_CTRL_HASH_TYPE_ALGORITHM_* - see above)
|
|
* value: Hash value
|
|
*/
|
|
|
|
/* Protocol checksum field is blank in the packet (hardware offload)? */
|
|
#define _XEN_NETTXF_csum_blank (0)
|
|
#define XEN_NETTXF_csum_blank (1U<<_XEN_NETTXF_csum_blank)
|
|
|
|
/* Packet data has been validated against protocol checksum. */
|
|
#define _XEN_NETTXF_data_validated (1)
|
|
#define XEN_NETTXF_data_validated (1U<<_XEN_NETTXF_data_validated)
|
|
|
|
/* Packet continues in the next request descriptor. */
|
|
#define _XEN_NETTXF_more_data (2)
|
|
#define XEN_NETTXF_more_data (1U<<_XEN_NETTXF_more_data)
|
|
|
|
/* Packet to be followed by extra descriptor(s). */
|
|
#define _XEN_NETTXF_extra_info (3)
|
|
#define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info)
|
|
|
|
#define XEN_NETIF_MAX_TX_SIZE 0xFFFF
|
|
struct xen_netif_tx_request {
|
|
grant_ref_t gref;
|
|
uint16_t offset;
|
|
uint16_t flags;
|
|
uint16_t id;
|
|
uint16_t size;
|
|
};
|
|
|
|
/* Types of xen_netif_extra_info descriptors. */
|
|
#define XEN_NETIF_EXTRA_TYPE_NONE (0) /* Never used - invalid */
|
|
#define XEN_NETIF_EXTRA_TYPE_GSO (1) /* u.gso */
|
|
#define XEN_NETIF_EXTRA_TYPE_MCAST_ADD (2) /* u.mcast */
|
|
#define XEN_NETIF_EXTRA_TYPE_MCAST_DEL (3) /* u.mcast */
|
|
#define XEN_NETIF_EXTRA_TYPE_HASH (4) /* u.hash */
|
|
#define XEN_NETIF_EXTRA_TYPE_XDP (5) /* u.xdp */
|
|
#define XEN_NETIF_EXTRA_TYPE_MAX (6)
|
|
|
|
/* xen_netif_extra_info_t flags. */
|
|
#define _XEN_NETIF_EXTRA_FLAG_MORE (0)
|
|
#define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE)
|
|
|
|
/* GSO types */
|
|
#define XEN_NETIF_GSO_TYPE_NONE (0)
|
|
#define XEN_NETIF_GSO_TYPE_TCPV4 (1)
|
|
#define XEN_NETIF_GSO_TYPE_TCPV6 (2)
|
|
|
|
/*
|
|
* This structure needs to fit within both xen_netif_tx_request_t and
|
|
* xen_netif_rx_response_t for compatibility.
|
|
*/
|
|
struct xen_netif_extra_info {
|
|
uint8_t type;
|
|
uint8_t flags;
|
|
union {
|
|
struct {
|
|
uint16_t size;
|
|
uint8_t type;
|
|
uint8_t pad;
|
|
uint16_t features;
|
|
} gso;
|
|
struct {
|
|
uint8_t addr[6];
|
|
} mcast;
|
|
struct {
|
|
uint8_t type;
|
|
uint8_t algorithm;
|
|
uint8_t value[4];
|
|
} hash;
|
|
struct {
|
|
uint16_t headroom;
|
|
uint16_t pad[2];
|
|
} xdp;
|
|
uint16_t pad[3];
|
|
} u;
|
|
};
|
|
|
|
struct xen_netif_tx_response {
|
|
uint16_t id;
|
|
int16_t status;
|
|
};
|
|
|
|
struct xen_netif_rx_request {
|
|
uint16_t id; /* Echoed in response message. */
|
|
uint16_t pad;
|
|
grant_ref_t gref;
|
|
};
|
|
|
|
/* Packet data has been validated against protocol checksum. */
|
|
#define _XEN_NETRXF_data_validated (0)
|
|
#define XEN_NETRXF_data_validated (1U<<_XEN_NETRXF_data_validated)
|
|
|
|
/* Protocol checksum field is blank in the packet (hardware offload)? */
|
|
#define _XEN_NETRXF_csum_blank (1)
|
|
#define XEN_NETRXF_csum_blank (1U<<_XEN_NETRXF_csum_blank)
|
|
|
|
/* Packet continues in the next request descriptor. */
|
|
#define _XEN_NETRXF_more_data (2)
|
|
#define XEN_NETRXF_more_data (1U<<_XEN_NETRXF_more_data)
|
|
|
|
/* Packet to be followed by extra descriptor(s). */
|
|
#define _XEN_NETRXF_extra_info (3)
|
|
#define XEN_NETRXF_extra_info (1U<<_XEN_NETRXF_extra_info)
|
|
|
|
/* Packet has GSO prefix. Deprecated but included for compatibility */
|
|
#define _XEN_NETRXF_gso_prefix (4)
|
|
#define XEN_NETRXF_gso_prefix (1U<<_XEN_NETRXF_gso_prefix)
|
|
|
|
struct xen_netif_rx_response {
|
|
uint16_t id;
|
|
uint16_t offset;
|
|
uint16_t flags;
|
|
int16_t status;
|
|
};
|
|
|
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/*
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* Generate xen_netif ring structures and types.
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*/
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DEFINE_RING_TYPES(xen_netif_tx, struct xen_netif_tx_request,
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struct xen_netif_tx_response);
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DEFINE_RING_TYPES(xen_netif_rx, struct xen_netif_rx_request,
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struct xen_netif_rx_response);
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#define XEN_NETIF_RSP_DROPPED -2
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#define XEN_NETIF_RSP_ERROR -1
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#define XEN_NETIF_RSP_OKAY 0
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/* No response: used for auxiliary requests (e.g., xen_netif_extra_info_t). */
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#define XEN_NETIF_RSP_NULL 1
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#endif
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