/*-
 * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _IF_VTNETVAR_H
#define _IF_VTNETVAR_H

struct vtnet_statistics {
        uint64_t        mbuf_alloc_failed;

        uint64_t        rx_frame_too_large;
        uint64_t        rx_enq_replacement_failed;
        uint64_t        rx_mergeable_failed;
        uint64_t        rx_csum_bad_ethtype;
        uint64_t        rx_csum_bad_ipproto;
        uint64_t        rx_csum_bad_offset;
        uint64_t        rx_csum_failed;
        uint64_t        rx_csum_offloaded;
        uint64_t        rx_task_rescheduled;

        uint64_t        tx_csum_offloaded;
        uint64_t        tx_tso_offloaded;
        uint64_t        tx_csum_bad_ethtype;
        uint64_t        tx_tso_bad_ethtype;
        uint64_t        tx_defragged;
        uint64_t        tx_defrag_failed;
        uint64_t        tx_task_rescheduled;
};

struct irqmap {
        int irq;
        driver_intr_t *handler;
};

struct vtnet_softc {
        device_t                vtnet_dev;
        struct ifnet            *vtnet_ifp;
        struct lwkt_serialize   vtnet_slz;
        struct lwkt_serialize   vtnet_rx_slz;
        struct lwkt_serialize   vtnet_tx_slz;
        struct lwkt_serialize   *serializes[3];

        uint32_t                vtnet_flags;
#define VTNET_FLAG_LINK         0x0001
#define VTNET_FLAG_SUSPENDED    0x0002
#define VTNET_FLAG_MAC          0x0004
#define VTNET_FLAG_CTRL_VQ      0x0008
#define VTNET_FLAG_CTRL_RX      0x0010
#define VTNET_FLAG_CTRL_MAC     0x0020
#define VTNET_FLAG_VLAN_FILTER  0x0040
#define VTNET_FLAG_TSO_ECN      0x0080
#define VTNET_FLAG_MRG_RXBUFS   0x0100
#define VTNET_FLAG_LRO_NOMRG    0x0200
#define VTNET_FLAG_INDIRECT     0x0400

        struct virtqueue        *vtnet_rx_vq;
        struct virtqueue        *vtnet_tx_vq;
        struct virtqueue        *vtnet_ctrl_vq;

        /* controlq, rx, tx and config_change */
        int                     vtnet_cpus[4];
        int                     vtnet_nintr;

        struct irqmap           vtnet_irqmap[2];
        struct lwkt_serialize   *vtnet_intr_slz[3];

        int                     vtnet_txhdrcount;
        struct vtnet_tx_header  *vtnet_txhdrarea;
        SLIST_HEAD(, vtnet_tx_header)
                                vtnet_txhdr_free;
        struct vtnet_mac_filter *vtnet_macfilter;

        int                     vtnet_hdr_size;
        int                     vtnet_tx_size;
        int                     vtnet_tx_nsegs;
        int                     vtnet_rx_process_limit;
        int                     vtnet_rx_nsegs;
        int                     vtnet_rx_mbuf_size;
        int                     vtnet_rx_mbuf_count;
        int                     vtnet_if_flags;
        struct ifsubq_watchdog  vtnet_tx_watchdog;
        uint64_t                vtnet_features;

        struct vtnet_statistics vtnet_stats;

        eventhandler_tag        vtnet_vlan_attach;
        eventhandler_tag        vtnet_vlan_detach;

        struct ifmedia          vtnet_media;
        /*
         * Fake media type; the host does not provide us with
         * any real media information.
         */
#define VTNET_MEDIATYPE         (IFM_ETHER | IFM_1000_T | IFM_FDX)
        char                    vtnet_hwaddr[ETHER_ADDR_LEN];

        /*
         * During reset, the host's VLAN filtering table is lost. The
         * array below is used to restore all the VLANs configured on
         * this interface after a reset.
         */
#define VTNET_VLAN_SHADOW_SIZE  (4096 / 32)
        int                     vtnet_nvlans;
        uint32_t                vtnet_vlan_shadow[VTNET_VLAN_SHADOW_SIZE];
};

/*
 * When mergeable buffers are not negotiated, the vtnet_rx_header structure
 * below is placed at the beginning of the mbuf data. Use 2 bytes of pad to
 * both keep the VirtIO header and the data non-contiguous and to keep the
 * frame's payload 4 byte aligned.
 *
 * When mergeable buffers are negotiated, the host puts the VirtIO header in
 * the beginning of the first mbuf's data.
 */
#define VTNET_RX_HEADER_PAD     2
struct vtnet_rx_header {
        struct virtio_net_hdr   vrh_hdr;
        char                    vrh_pad[VTNET_RX_HEADER_PAD];
} __packed;

/*
 * For each outgoing frame, the vtnet_tx_header below is allocated from
 * a free-list.
 */
struct vtnet_tx_header {
        union {
                struct virtio_net_hdr           hdr;
                struct virtio_net_hdr_mrg_rxbuf mhdr;
        } vth_uhdr;

        struct mbuf *vth_mbuf;
        SLIST_ENTRY(vtnet_tx_header) link;
};

/*
 * The VirtIO specification does not place a limit on the number of MAC
 * addresses the guest driver may request to be filtered. In practice,
 * the host is constrained by available resources. To simplify this driver,
 * impose a reasonably high limit of MAC addresses we will filter before
 * falling back to promiscuous or all-multicast modes.
 */
#define VTNET_MAX_MAC_ENTRIES   128

struct vtnet_mac_table {
        uint32_t        nentries;
        uint8_t         macs[VTNET_MAX_MAC_ENTRIES][ETHER_ADDR_LEN];
} __packed;

struct vtnet_mac_filter {
        struct vtnet_mac_table  vmf_unicast;
        uint32_t                vmf_pad; /* Make tables non-contiguous. */
        struct vtnet_mac_table  vmf_multicast;
};

#define VTNET_WATCHDOG_TIMEOUT  5
#define VTNET_CSUM_OFFLOAD      (CSUM_TCP | CSUM_UDP)

/* Features desired/implemented by this driver. */
#define VTNET_FEATURES          \
    (VIRTIO_NET_F_MAC           | \
     VIRTIO_NET_F_STATUS        | \
     VIRTIO_NET_F_CTRL_VQ       | \
     VIRTIO_NET_F_CTRL_RX       | \
     VIRTIO_NET_F_CTRL_MAC_ADDR | \
     VIRTIO_NET_F_CTRL_VLAN     | \
     VIRTIO_NET_F_CSUM          | \
     VIRTIO_NET_F_HOST_TSO4     | \
     VIRTIO_NET_F_HOST_TSO6     | \
     VIRTIO_NET_F_HOST_ECN      | \
     VIRTIO_NET_F_GUEST_CSUM    | \
     VIRTIO_NET_F_GUEST_TSO4    | \
     VIRTIO_NET_F_GUEST_TSO6    | \
     VIRTIO_NET_F_GUEST_ECN     | \
     VIRTIO_NET_F_MRG_RXBUF     | \
     VIRTIO_RING_F_INDIRECT_DESC)

/*
 * The VIRTIO_NET_F_GUEST_TSO[46] features permit the host to send us
 * frames larger than 1514 bytes. We do not yet support software LRO
 * via tcp_lro_rx().
 */
#define VTNET_LRO_FEATURES (VIRTIO_NET_F_GUEST_TSO4 | \
                            VIRTIO_NET_F_GUEST_TSO6 | VIRTIO_NET_F_GUEST_ECN)

#define VTNET_MAX_MTU           65536
#define VTNET_MAX_RX_SIZE       65550

/*
 * Used to preallocate the Vq indirect descriptors. The first segment
 * is reserved for the header.
 */
#define VTNET_MRG_RX_SEGS       1
#define VTNET_MIN_RX_SEGS       2
#define VTNET_MAX_RX_SEGS       34
#define VTNET_MIN_TX_SEGS       4
#define VTNET_MAX_TX_SEGS       64

#if 0   /* Copied from FreeBSD's net/if.h at some time, but not usable. */
#define IFCAP_LRO               0x00400 /* can do Large Receive Offload */
#define IFCAP_VLAN_HWFILTER     0x10000 /* interface hw can filter vlan tag */
#define IFCAP_VLAN_HWTSO        0x40000 /* can do IFCAP_TSO on VLANs */
#endif

/*
 * This allows lots of code to at least build, even if it's never executed
 * at the moment.
 */
#ifndef IFCAP_VLAN_HWFILTER
#define IFCAP_VLAN_HWFILTER     0
#endif
#ifndef IFCAP_VLAN_HWTSO
#define IFCAP_VLAN_HWTSO        0
#endif

/*
 * Assert we can receive and transmit the maximum with regular
 * size clusters.
 */
CTASSERT(((VTNET_MAX_RX_SEGS - 1) * MCLBYTES) >= VTNET_MAX_RX_SIZE);
CTASSERT(((VTNET_MAX_TX_SEGS - 1) * MCLBYTES) >= VTNET_MAX_MTU);

/*
 * Determine how many mbufs are in each receive buffer. For LRO without
 * mergeable buffers, we must allocate an mbuf chain large enough to
 * hold both the vtnet_rx_header and the maximum receivable data.
 */
#define VTNET_NEEDED_RX_MBUFS(_sc)                                      \
        ((_sc)->vtnet_flags & VTNET_FLAG_LRO_NOMRG) == 0 ? 1 :          \
        howmany(sizeof(struct vtnet_rx_header) + VTNET_MAX_RX_SIZE,     \
        (_sc)->vtnet_rx_mbuf_size)

#endif /* _IF_VTNETVAR_H */