| /****************************************************************************** |
| * netif.h |
| * |
| * Unified network-device I/O interface for Xen guest OSes. |
| * |
| * Copyright (c) 2003-2004, Keir Fraser |
| */ |
| |
| #ifndef __XEN_PUBLIC_IO_NETIF_H__ |
| #define __XEN_PUBLIC_IO_NETIF_H__ |
| |
| #include <xen/interface/io/ring.h> |
| #include <xen/interface/grant_table.h> |
| |
| /* |
| * Older implementation of Xen network frontend / backend has an |
| * implicit dependency on the MAX_SKB_FRAGS as the maximum number of |
| * ring slots a skb can use. Netfront / netback may not work as |
| * expected when frontend and backend have different MAX_SKB_FRAGS. |
| * |
| * A better approach is to add mechanism for netfront / netback to |
| * negotiate this value. However we cannot fix all possible |
| * frontends, so we need to define a value which states the minimum |
| * slots backend must support. |
| * |
| * The minimum value derives from older Linux kernel's MAX_SKB_FRAGS |
| * (18), which is proved to work with most frontends. Any new backend |
| * which doesn't negotiate with frontend should expect frontend to |
| * send a valid packet using slots up to this value. |
| */ |
| #define XEN_NETIF_NR_SLOTS_MIN 18 |
| |
| /* |
| * Notifications after enqueuing any type of message should be conditional on |
| * the appropriate req_event or rsp_event field in the shared ring. |
| * If the client sends notification for rx requests then it should specify |
| * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume |
| * that it cannot safely queue packets (as it may not be kicked to send them). |
| */ |
| |
| /* |
| * "feature-split-event-channels" is introduced to separate guest TX |
| * and RX notificaion. Backend either doesn't support this feature or |
| * advertise it via xenstore as 0 (disabled) or 1 (enabled). |
| * |
| * To make use of this feature, frontend should allocate two event |
| * channels for TX and RX, advertise them to backend as |
| * "event-channel-tx" and "event-channel-rx" respectively. If frontend |
| * doesn't want to use this feature, it just writes "event-channel" |
| * node as before. |
| */ |
| |
| /* |
| * Multiple transmit and receive queues: |
| * If supported, the backend will write the key "multi-queue-max-queues" to |
| * the directory for that vif, and set its value to the maximum supported |
| * number of queues. |
| * Frontends that are aware of this feature and wish to use it can write the |
| * key "multi-queue-num-queues", set to the number they wish to use, which |
| * must be greater than zero, and no more than the value reported by the backend |
| * in "multi-queue-max-queues". |
| * |
| * Queues replicate the shared rings and event channels. |
| * "feature-split-event-channels" may optionally be used when using |
| * multiple queues, but is not mandatory. |
| * |
| * Each queue consists of one shared ring pair, i.e. there must be the same |
| * number of tx and rx rings. |
| * |
| * For frontends requesting just one queue, the usual event-channel and |
| * ring-ref keys are written as before, simplifying the backend processing |
| * to avoid distinguishing between a frontend that doesn't understand the |
| * multi-queue feature, and one that does, but requested only one queue. |
| * |
| * Frontends requesting two or more queues must not write the toplevel |
| * event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys, |
| * instead writing those keys under sub-keys having the name "queue-N" where |
| * N is the integer ID of the queue for which those keys belong. Queues |
| * are indexed from zero. For example, a frontend with two queues and split |
| * event channels must write the following set of queue-related keys: |
| * |
| * /local/domain/1/device/vif/0/multi-queue-num-queues = "2" |
| * /local/domain/1/device/vif/0/queue-0 = "" |
| * /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>" |
| * /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>" |
| * /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>" |
| * /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>" |
| * /local/domain/1/device/vif/0/queue-1 = "" |
| * /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>" |
| * /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1" |
| * /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>" |
| * /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>" |
| * |
| * If there is any inconsistency in the XenStore data, the backend may |
| * choose not to connect any queues, instead treating the request as an |
| * error. This includes scenarios where more (or fewer) queues were |
| * requested than the frontend provided details for. |
| * |
| * Mapping of packets to queues is considered to be a function of the |
| * transmitting system (backend or frontend) and is not negotiated |
| * between the two. Guests are free to transmit packets on any queue |
| * they choose, provided it has been set up correctly. Guests must be |
| * prepared to receive packets on any queue they have requested be set up. |
| */ |
| |
| /* |
| * "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum |
| * offload off or on. If it is missing then the feature is assumed to be on. |
| * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum |
| * offload on or off. If it is missing then the feature is assumed to be off. |
| */ |
| |
| /* |
| * "feature-gso-tcpv4" and "feature-gso-tcpv6" advertise the capability to |
| * handle large TCP packets (in IPv4 or IPv6 form respectively). Neither |
| * frontends nor backends are assumed to be capable unless the flags are |
| * present. |
| */ |
| |
| /* |
| * This is the 'wire' format for packets: |
| * Request 1: xen_netif_tx_request -- XEN_NETTXF_* (any flags) |
| * [Request 2: xen_netif_extra_info] (only if request 1 has XEN_NETTXF_extra_info) |
| * [Request 3: xen_netif_extra_info] (only if request 2 has XEN_NETIF_EXTRA_MORE) |
| * Request 4: xen_netif_tx_request -- XEN_NETTXF_more_data |
| * Request 5: xen_netif_tx_request -- XEN_NETTXF_more_data |
| * ... |
| * Request N: xen_netif_tx_request -- 0 |
| */ |
| |
| /* 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; /* Reference to buffer page */ |
| uint16_t offset; /* Offset within buffer page */ |
| uint16_t flags; /* XEN_NETTXF_* */ |
| uint16_t id; /* Echoed in response message. */ |
| uint16_t size; /* Packet size in bytes. */ |
| }; |
| |
| /* 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_MAX (4) |
| |
| /* xen_netif_extra_info 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 netif_tx_request and |
| * netif_rx_response for compatibility. |
| */ |
| struct xen_netif_extra_info { |
| uint8_t type; /* XEN_NETIF_EXTRA_TYPE_* */ |
| uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */ |
| |
| union { |
| struct { |
| /* |
| * Maximum payload size of each segment. For |
| * example, for TCP this is just the path MSS. |
| */ |
| uint16_t size; |
| |
| /* |
| * GSO type. This determines the protocol of |
| * the packet and any extra features required |
| * to segment the packet properly. |
| */ |
| uint8_t type; /* XEN_NETIF_GSO_TYPE_* */ |
| |
| /* Future expansion. */ |
| uint8_t pad; |
| |
| /* |
| * GSO features. This specifies any extra GSO |
| * features required to process this packet, |
| * such as ECN support for TCPv4. |
| */ |
| uint16_t features; /* XEN_NETIF_GSO_FEAT_* */ |
| } gso; |
| |
| struct { |
| uint8_t addr[6]; /* Address to add/remove. */ |
| } mcast; |
| |
| uint16_t pad[3]; |
| } u; |
| }; |
| |
| struct xen_netif_tx_response { |
| uint16_t id; |
| int16_t status; /* XEN_NETIF_RSP_* */ |
| }; |
| |
| struct xen_netif_rx_request { |
| uint16_t id; /* Echoed in response message. */ |
| grant_ref_t gref; /* Reference to incoming granted frame */ |
| }; |
| |
| /* 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) |
| |
| /* GSO Prefix descriptor. */ |
| #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; /* Offset in page of start of received packet */ |
| uint16_t flags; /* XEN_NETRXF_* */ |
| int16_t status; /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */ |
| }; |
| |
| /* |
| * Generate netif ring structures and types. |
| */ |
| |
| DEFINE_RING_TYPES(xen_netif_tx, |
| struct xen_netif_tx_request, |
| struct xen_netif_tx_response); |
| DEFINE_RING_TYPES(xen_netif_rx, |
| struct xen_netif_rx_request, |
| struct xen_netif_rx_response); |
| |
| #define XEN_NETIF_RSP_DROPPED -2 |
| #define XEN_NETIF_RSP_ERROR -1 |
| #define XEN_NETIF_RSP_OKAY 0 |
| /* No response: used for auxiliary requests (e.g., xen_netif_extra_info). */ |
| #define XEN_NETIF_RSP_NULL 1 |
| |
| #endif |