/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright 2024 OmniOS Community Edition (OmniOSce) Association.
 *
 * 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, 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 AND CONTRIBUTORS``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 OR CONTRIBUTORS
 * 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.
 */

/*
 * The illumos dlpi backend
 */

#include <sys/types.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <net/ethernet.h>
#include <libdlpi.h>

#include "config.h"
#include "debug.h"
#include "iov.h"
#include "mevent.h"
#include "net_backends.h"
#include "net_backends_priv.h"

/*
 * The size of the bounce buffer used to implement the peek callback.
 * This value should be big enough to accommodate the largest of all possible
 * frontend packet lengths. The value here matches the definition of
 * VTNET_MAX_PKT_LEN in pci_virtio_net.c
 */
#define DLPI_BBUF_SIZE (65536 + 64)

typedef struct be_dlpi_priv {
        dlpi_handle_t bdp_dhp;
        struct mevent *bdp_mevp;
        /*
         * A bounce buffer that allows us to implement the peek_recvlen
         * callback. Each structure is only used by a single thread so
         * one is enough.
         */
        uint8_t bdp_bbuf[DLPI_BBUF_SIZE];
        ssize_t bdp_bbuflen;
} be_dlpi_priv_t;

static void
be_dlpi_cleanup(net_backend_t *be)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);

        if (priv->bdp_dhp != NULL)
                dlpi_close(priv->bdp_dhp);
        priv->bdp_dhp = NULL;

        if (priv->bdp_mevp != NULL)
                mevent_delete(priv->bdp_mevp);
        priv->bdp_mevp = NULL;

        priv->bdp_bbuflen = 0;
        be->fd = -1;
}

static void
be_dlpi_err(int ret, const char *dev, char *msg)
{
        EPRINTLN("%s: %s (%s)", dev, msg, dlpi_strerror(ret));
}

static int
be_dlpi_init(net_backend_t *be, const char *devname __unused,
     nvlist_t *nvl, net_be_rxeof_t cb, void *param)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);
        const char *vnic;
        int ret;

        if (cb == NULL) {
                EPRINTLN("dlpi backend requires non-NULL callback");
                return (-1);
        }

        vnic = get_config_value_node(nvl, "vnic");
        if (vnic == NULL) {
                EPRINTLN("dlpi backend requires a VNIC");
                return (-1);
        }

        priv->bdp_bbuflen = 0;

        ret = dlpi_open(vnic, &priv->bdp_dhp, DLPI_RAW);

        if (ret != DLPI_SUCCESS) {
                be_dlpi_err(ret, vnic, "open failed");
                goto error;
        }

        if ((ret = dlpi_bind(priv->bdp_dhp, DLPI_ANY_SAP, NULL)) !=
            DLPI_SUCCESS) {
                be_dlpi_err(ret, vnic, "bind failed");
                goto error;
        }

        if (get_config_bool_node_default(nvl, "promiscrxonly", true)) {
                if ((ret = dlpi_promiscon(priv->bdp_dhp, DL_PROMISC_RX_ONLY)) !=
                    DLPI_SUCCESS) {
                        be_dlpi_err(ret, vnic,
                            "enable promiscuous mode(rxonly) failed");
                        goto error;
                }
        }
        if (get_config_bool_node_default(nvl, "promiscphys", false)) {
                if ((ret = dlpi_promiscon(priv->bdp_dhp, DL_PROMISC_PHYS)) !=
                    DLPI_SUCCESS) {
                        be_dlpi_err(ret, vnic,
                            "enable promiscuous mode(physical) failed");
                        goto error;
                }
        }
        if (get_config_bool_node_default(nvl, "promiscsap", true)) {
                if ((ret = dlpi_promiscon(priv->bdp_dhp, DL_PROMISC_SAP)) !=
                    DLPI_SUCCESS) {
                        be_dlpi_err(ret, vnic,
                            "enable promiscuous mode(SAP) failed");
                        goto error;
                }
        }
        if (get_config_bool_node_default(nvl, "promiscmulti", true)) {
                if ((ret = dlpi_promiscon(priv->bdp_dhp, DL_PROMISC_MULTI)) !=
                    DLPI_SUCCESS) {
                        be_dlpi_err(ret, vnic,
                            "enable promiscuous mode(muticast) failed");
                        goto error;
                }
        }

        be->fd = dlpi_fd(priv->bdp_dhp);

        if (fcntl(be->fd, F_SETFL, O_NONBLOCK) < 0) {
                EPRINTLN("%s: enable O_NONBLOCK failed", vnic);
                goto error;
        }

        priv->bdp_mevp = mevent_add_disabled(be->fd, EVF_READ, cb, param);
        if (priv->bdp_mevp == NULL) {
                EPRINTLN("Could not register event");
                goto error;
        }

        return (0);

error:
        be_dlpi_cleanup(be);
        return (-1);
}

/*
 * Called to send a buffer chain out to the dlpi device
 */
static ssize_t
be_dlpi_send(net_backend_t *be, const struct iovec *iov, int iovcnt)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);
        ssize_t len = 0;
        int ret;

        if (iovcnt == 1) {
                len = iov[0].iov_len;
                ret = dlpi_send(priv->bdp_dhp, NULL, 0, iov[0].iov_base, len,
                    NULL);
        } else {
                void *buf = NULL;

                len = iov_to_buf(iov, iovcnt, &buf);

                if (len <= 0 || buf == NULL)
                        return (-1);

                ret = dlpi_send(priv->bdp_dhp, NULL, 0, buf, len, NULL);
                free(buf);
        }

        if (ret != DLPI_SUCCESS)
                return (-1);

        return (len);
}

static ssize_t
be_dlpi_peek_recvlen(net_backend_t *be)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);
        dlpi_recvinfo_t recv;
        size_t len;
        int ret;

        /*
         * We already have a packet in the bounce buffer.
         * Just return its length.
         */
        if (priv->bdp_bbuflen > 0)
                return (priv->bdp_bbuflen);

        /*
         * Read the next packet (if any) into the bounce buffer, so
         * that we get to know its length and we can return that
         * to the caller.
         */
        len = sizeof (priv->bdp_bbuf);
        ret = dlpi_recv(priv->bdp_dhp, NULL, NULL, priv->bdp_bbuf, &len,
            0, &recv);
        if (ret == DL_SYSERR) {
                if (errno == EWOULDBLOCK)
                        return (0);
                return (-1);
        } else if (ret == DLPI_ETIMEDOUT) {
                return (0);
        } else if (ret != DLPI_SUCCESS) {
                return (-1);
        }

        if (recv.dri_totmsglen > sizeof (priv->bdp_bbuf)) {
                EPRINTLN("DLPI bounce buffer was too small! - needed %x bytes",
                    recv.dri_totmsglen);
        }

        priv->bdp_bbuflen = len;

        return (len);
}

static ssize_t
be_dlpi_recv(net_backend_t *be, const struct iovec *iov, int iovcnt)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);
        size_t len;
        int ret;

        if (priv->bdp_bbuflen > 0) {
                /*
                 * A packet is available in the bounce buffer, so
                 * we read it from there.
                 */
                len = buf_to_iov(priv->bdp_bbuf, priv->bdp_bbuflen,
                    iov, iovcnt);

                /* Mark the bounce buffer as empty. */
                priv->bdp_bbuflen = 0;

                if (len == 0)
                        return (-1);

                return (len);
        }

        len = iov[0].iov_len;
        ret = dlpi_recv(priv->bdp_dhp, NULL, NULL,
            (uint8_t *)iov[0].iov_base, &len, 0, NULL);
        if (ret == DL_SYSERR) {
                if (errno == EWOULDBLOCK)
                        return (0);
                return (-1);
        } else if (ret == DLPI_ETIMEDOUT) {
                return (0);
        } else if (ret != DLPI_SUCCESS) {
                return (-1);
        }

        return (len);
}

static void
be_dlpi_recv_enable(net_backend_t *be)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);

        mevent_enable(priv->bdp_mevp);
}

static void
be_dlpi_recv_disable(net_backend_t *be)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);

        mevent_disable(priv->bdp_mevp);
}

static uint64_t
be_dlpi_get_cap(net_backend_t *be)
{
        return (0); /* no capabilities for now */
}

static int
be_dlpi_set_cap(net_backend_t *be, uint64_t features,
    unsigned vnet_hdr_len)
{
        return ((features || vnet_hdr_len) ? -1 : 0);
}

static int
be_dlpi_get_mac(net_backend_t *be, void *buf, size_t *buflen)
{
        be_dlpi_priv_t *priv = NET_BE_PRIV(be);
        uchar_t physaddr[DLPI_PHYSADDR_MAX];
        size_t physaddrlen = DLPI_PHYSADDR_MAX;
        int ret;

        if ((ret = dlpi_get_physaddr(priv->bdp_dhp, DL_CURR_PHYS_ADDR,
            physaddr, &physaddrlen)) != DLPI_SUCCESS) {
                be_dlpi_err(ret, dlpi_linkname(priv->bdp_dhp),
                    "read MAC address failed");
                return (EINVAL);
        }

        if (physaddrlen != ETHERADDRL) {
                EPRINTLN("%s: bad MAC address len %d",
                    dlpi_linkname(priv->bdp_dhp), physaddrlen);
                return (EINVAL);
        }

        if (physaddrlen > *buflen) {
                EPRINTLN("%s: MAC address too long (%d bytes required)",
                    dlpi_linkname(priv->bdp_dhp), physaddrlen);
                return (ENOMEM);
        }

        *buflen = physaddrlen;
        memcpy(buf, physaddr, *buflen);

        return (0);
}

static struct net_backend dlpi_backend = {
        .prefix = "dlpi",
        .priv_size = sizeof(struct be_dlpi_priv),
        .init = be_dlpi_init,
        .cleanup = be_dlpi_cleanup,
        .send = be_dlpi_send,
        .peek_recvlen = be_dlpi_peek_recvlen,
        .recv = be_dlpi_recv,
        .recv_enable = be_dlpi_recv_enable,
        .recv_disable = be_dlpi_recv_disable,
        .get_cap = be_dlpi_get_cap,
        .set_cap = be_dlpi_set_cap,
        .get_mac = be_dlpi_get_mac,
};

DATA_SET(net_backend_set, dlpi_backend);