FreeBSD/Linux Kernel Cross Reference
sys/xen/interface/io/netif.h

     /******************************************************************************
      * netif.h
      * 
      * Unified network-device I/O interface for Xen guest OSes.
      * 
      * Permission is hereby granted, free of charge, to any person obtaining a copy
      * of this software and associated documentation files (the "Software"), to
      * deal in the Software without restriction, including without limitation the
      * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     * DEALINGS IN THE SOFTWARE.
     *
     * Copyright (c) 2003-2004, Keir Fraser
     */
    
    #ifndef __XEN_PUBLIC_IO_NETIF_H__
    #define __XEN_PUBLIC_IO_NETIF_H__
    
    #include "ring.h"
    #include "../grant_table.h"
    
    /*
     * 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).
     */
    
    /*
     * This is the 'wire' format for packets:
     *  Request 1: netif_tx_request -- NETTXF_* (any flags)
     * [Request 2: netif_tx_extra] (only if request 1 has NETTXF_extra_info)
     * [Request 3: netif_tx_extra] (only if request 2 has XEN_NETIF_EXTRA_FLAG_MORE)
     *  Request 4: netif_tx_request -- NETTXF_more_data
     *  Request 5: netif_tx_request -- NETTXF_more_data
     *  ...
     *  Request N: netif_tx_request -- 0
     */
    
    /* Protocol checksum field is blank in the packet (hardware offload)? */
    #define _NETTXF_csum_blank     (0)
    #define  NETTXF_csum_blank     (1U<<_NETTXF_csum_blank)
    
    /* Packet data has been validated against protocol checksum. */
    #define _NETTXF_data_validated (1)
    #define  NETTXF_data_validated (1U<<_NETTXF_data_validated)
    
    /* Packet continues in the next request descriptor. */
    #define _NETTXF_more_data      (2)
    #define  NETTXF_more_data      (1U<<_NETTXF_more_data)
    
    /* Packet to be followed by extra descriptor(s). */
    #define _NETTXF_extra_info     (3)
    #define  NETTXF_extra_info     (1U<<_NETTXF_extra_info)
    
    struct netif_tx_request {
        grant_ref_t gref;      /* Reference to buffer page */
        uint16_t offset;       /* Offset within buffer page */
        uint16_t flags;        /* NETTXF_* */
        uint16_t id;           /* Echoed in response message. */
        uint16_t size;         /* For the first request in a packet, the packet 
                                  size in bytes.  For subsequent requests, the 
                                  size of that request's associated data in bytes*/
    };
    typedef struct netif_tx_request netif_tx_request_t;
    
    /* Types of 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)
    
    /* 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 - only TCPv4 currently supported. */
    #define XEN_NETIF_GSO_TYPE_TCPV4        (1)
    
    /*
     * This structure needs to fit within both netif_tx_request and
     * netif_rx_response for compatibility.
     */
    struct netif_extra_info {
        uint8_t type;  /* XEN_NETIF_EXTRA_TYPE_* */
        uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */
   
       union {
           /*
            * XEN_NETIF_EXTRA_TYPE_GSO:
            */
           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;
   
           /*
            * XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}:
            * Backend advertises availability via 'feature-multicast-control'
            * xenbus node containing value '1'.
            * Frontend requests this feature by advertising
            * 'request-multicast-control' xenbus node containing value '1'.
            * If multicast control is requested then multicast flooding is
            * disabled and the frontend must explicitly register its interest
            * in multicast groups using dummy transmit requests containing
            * MCAST_{ADD,DEL} extra-info fragments.
            */
           struct {
               uint8_t addr[6]; /* Address to add/remove. */
           } mcast;
   
           uint16_t pad[3];
       } u;
   };
   typedef struct netif_extra_info netif_extra_info_t;
   
   struct netif_tx_response {
       uint16_t id;
       int16_t  status;       /* NETIF_RSP_* */
   };
   typedef struct netif_tx_response netif_tx_response_t;
   
   struct netif_rx_request {
       uint16_t    id;        /* Echoed in response message.        */
       grant_ref_t gref;      /* Reference to incoming granted frame */
   };
   typedef struct netif_rx_request netif_rx_request_t;
   
   /* Packet data has been validated against protocol checksum. */
   #define _NETRXF_data_validated (0)
   #define  NETRXF_data_validated (1U<<_NETRXF_data_validated)
   
   /* Protocol checksum field is blank in the packet (hardware offload)? */
   #define _NETRXF_csum_blank     (1)
   #define  NETRXF_csum_blank     (1U<<_NETRXF_csum_blank)
   
   /* Packet continues in the next request descriptor. */
   #define _NETRXF_more_data      (2)
   #define  NETRXF_more_data      (1U<<_NETRXF_more_data)
   
   /* Packet to be followed by extra descriptor(s). */
   #define _NETRXF_extra_info     (3)
   #define  NETRXF_extra_info     (1U<<_NETRXF_extra_info)
   
   /* GSO Prefix descriptor. */
   #define _NETRXF_gso_prefix     (4)
   #define  NETRXF_gso_prefix     (1U<<_NETRXF_gso_prefix)
   
   struct netif_rx_response {
       uint16_t id;
       uint16_t offset;       /* Offset in page of start of received packet  */
       uint16_t flags;        /* NETRXF_* */
       int16_t  status;       /* -ve: NETIF_RSP_* ; +ve: Rx'ed response size. */
   };
   typedef struct netif_rx_response netif_rx_response_t;
   
   /*
    * Generate netif ring structures and types.
    */
   
   DEFINE_RING_TYPES(netif_tx, struct netif_tx_request, struct netif_tx_response);
   DEFINE_RING_TYPES(netif_rx, struct netif_rx_request, struct netif_rx_response);
   
   #define NETIF_RSP_DROPPED         -2
   #define NETIF_RSP_ERROR           -1
   #define NETIF_RSP_OKAY             0
   /* No response: used for auxiliary requests (e.g., netif_tx_extra). */
   #define NETIF_RSP_NULL             1
   
   #endif
   
   /*
    * Local variables:
    * mode: C
    * c-set-style: "BSD"
    * c-basic-offset: 4
    * tab-width: 4
    * indent-tabs-mode: nil
    * End:
    */

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