/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 *   OWNER 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.
 */

#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/mman.h>
#include <unistd.h>
#include <sys/eventfd.h>

#include "vhost.h"
#include "virtio_user_dev.h"
#include "../virtio_ethdev.h"

static int
virtio_user_create_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
{
	/* Of all per virtqueue MSGs, make sure VHOST_SET_VRING_CALL come
	 * firstly because vhost depends on this msg to allocate virtqueue
	 * pair.
	 */
	int callfd;
	struct vhost_vring_file file;

	/* May use invalid flag, but some backend leverages kickfd and callfd as
	 * criteria to judge if dev is alive. so finally we use real event_fd.
	 */
	callfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
	if (callfd < 0) {
		PMD_DRV_LOG(ERR, "callfd error, %s\n", strerror(errno));
		return -1;
	}
	file.index = queue_sel;
	file.fd = callfd;
	vhost_user_sock(dev->vhostfd, VHOST_USER_SET_VRING_CALL, &file);
	dev->callfds[queue_sel] = callfd;

	return 0;
}

static int
virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
{
	int kickfd;
	struct vhost_vring_file file;
	struct vhost_vring_state state;
	struct vring *vring = &dev->vrings[queue_sel];
	struct vhost_vring_addr addr = {
		.index = queue_sel,
		.desc_user_addr = (uint64_t)(uintptr_t)vring->desc,
		.avail_user_addr = (uint64_t)(uintptr_t)vring->avail,
		.used_user_addr = (uint64_t)(uintptr_t)vring->used,
		.log_guest_addr = 0,
		.flags = 0, /* disable log */
	};

	state.index = queue_sel;
	state.num = vring->num;
	vhost_user_sock(dev->vhostfd, VHOST_USER_SET_VRING_NUM, &state);

	state.num = 0; /* no reservation */
	vhost_user_sock(dev->vhostfd, VHOST_USER_SET_VRING_BASE, &state);

	vhost_user_sock(dev->vhostfd, VHOST_USER_SET_VRING_ADDR, &addr);

	/* Of all per virtqueue MSGs, make sure VHOST_USER_SET_VRING_KICK comes
	 * lastly because vhost depends on this msg to judge if
	 * virtio is ready.
	 */
	kickfd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
	if (kickfd < 0) {
		PMD_DRV_LOG(ERR, "kickfd error, %s\n", strerror(errno));
		return -1;
	}
	file.index = queue_sel;
	file.fd = kickfd;
	vhost_user_sock(dev->vhostfd, VHOST_USER_SET_VRING_KICK, &file);
	dev->kickfds[queue_sel] = kickfd;

	return 0;
}

static int
virtio_user_queue_setup(struct virtio_user_dev *dev,
			int (*fn)(struct virtio_user_dev *, uint32_t))
{
	uint32_t i, queue_sel;

	for (i = 0; i < dev->max_queue_pairs; ++i) {
		queue_sel = 2 * i + VTNET_SQ_RQ_QUEUE_IDX;
		if (fn(dev, queue_sel) < 0) {
			PMD_DRV_LOG(INFO, "setup rx vq fails: %u", i);
			return -1;
		}
	}
	for (i = 0; i < dev->max_queue_pairs; ++i) {
		queue_sel = 2 * i + VTNET_SQ_TQ_QUEUE_IDX;
		if (fn(dev, queue_sel) < 0) {
			PMD_DRV_LOG(INFO, "setup tx vq fails: %u", i);
			return -1;
		}
	}

	return 0;
}

int
virtio_user_start_device(struct virtio_user_dev *dev)
{
	uint64_t features;
	int ret;

	/* Step 0: tell vhost to create queues */
	if (virtio_user_queue_setup(dev, virtio_user_create_queue) < 0)
		goto error;

	/* Step 1: set features
	 * Make sure VHOST_USER_F_PROTOCOL_FEATURES is added if mq is enabled,
	 * VIRTIO_NET_F_MAC and VIRTIO_NET_F_CTRL_VQ is stripped.
	 */
	features = dev->features;
	if (dev->max_queue_pairs > 1)
		features |= VHOST_USER_MQ;
	features &= ~(1ull << VIRTIO_NET_F_MAC);
	features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
	ret = vhost_user_sock(dev->vhostfd, VHOST_USER_SET_FEATURES, &features);
	if (ret < 0)
		goto error;
	PMD_DRV_LOG(INFO, "set features: %" PRIx64, features);

	/* Step 2: share memory regions */
	ret = vhost_user_sock(dev->vhostfd, VHOST_USER_SET_MEM_TABLE, NULL);
	if (ret < 0)
		goto error;

	/* Step 3: kick queues */
	if (virtio_user_queue_setup(dev, virtio_user_kick_queue) < 0)
		goto error;

	/* Step 4: enable queues
	 * we enable the 1st queue pair by default.
	 */
	vhost_user_enable_queue_pair(dev->vhostfd, 0, 1);

	return 0;
error:
	/* TODO: free resource here or caller to check */
	return -1;
}

int virtio_user_stop_device(struct virtio_user_dev *dev)
{
	struct vhost_vring_state state;
	uint32_t i;

	for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
		close(dev->callfds[i]);
		close(dev->kickfds[i]);
	}

	for (i = 0; i < dev->max_queue_pairs; ++i)
		vhost_user_enable_queue_pair(dev->vhostfd, i, 0);

	/* Stop the backend. */
	for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
		state.index = i;
		if (vhost_user_sock(dev->vhostfd, VHOST_USER_GET_VRING_BASE,
					   &state) < 0) {
			PMD_DRV_LOG(ERR, "get_vring_base failed, index=%u\n",
				    i);
			return -1;
		}
	}

	return 0;
}

static inline void
parse_mac(struct virtio_user_dev *dev, const char *mac)
{
	int i, r;
	uint32_t tmp[ETHER_ADDR_LEN];

	if (!mac)
		return;

	r = sscanf(mac, "%x:%x:%x:%x:%x:%x", &tmp[0],
			&tmp[1], &tmp[2], &tmp[3], &tmp[4], &tmp[5]);
	if (r == ETHER_ADDR_LEN) {
		for (i = 0; i < ETHER_ADDR_LEN; ++i)
			dev->mac_addr[i] = (uint8_t)tmp[i];
		dev->mac_specified = 1;
	} else {
		/* ignore the wrong mac, use random mac */
		PMD_DRV_LOG(ERR, "wrong format of mac: %s", mac);
	}
}

int
virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
		     int cq, int queue_size, const char *mac)
{
	uint32_t i;

	snprintf(dev->path, PATH_MAX, "%s", path);
	dev->max_queue_pairs = queues;
	dev->queue_pairs = 1; /* mq disabled by default */
	dev->queue_size = queue_size;
	dev->mac_specified = 0;
	parse_mac(dev, mac);
	dev->vhostfd = -1;

	for (i = 0; i < VIRTIO_MAX_VIRTQUEUES; ++i) {
		dev->kickfds[i] = -1;
		dev->callfds[i] = -1;
	}

	dev->vhostfd = vhost_user_setup(dev->path);
	if (dev->vhostfd < 0) {
		PMD_INIT_LOG(ERR, "backend set up fails");
		return -1;
	}

	if (vhost_user_sock(dev->vhostfd, VHOST_USER_SET_OWNER, NULL) < 0) {
		PMD_INIT_LOG(ERR, "set_owner fails: %s", strerror(errno));
		return -1;
	}

	if (vhost_user_sock(dev->vhostfd, VHOST_USER_GET_FEATURES,
			    &dev->device_features) < 0) {
		PMD_INIT_LOG(ERR, "get_features failed: %s", strerror(errno));
		return -1;
	}
	if (dev->mac_specified)
		dev->device_features |= (1ull << VIRTIO_NET_F_MAC);

	if (cq) {
		/* device does not really need to know anything about CQ,
		 * so if necessary, we just claim to support CQ
		 */
		dev->device_features |= (1ull << VIRTIO_NET_F_CTRL_VQ);
	} else {
		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
		/* Also disable features depends on VIRTIO_NET_F_CTRL_VQ */
		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_RX);
		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
		dev->device_features &= ~(1ull << VIRTIO_NET_F_GUEST_ANNOUNCE);
		dev->device_features &= ~(1ull << VIRTIO_NET_F_MQ);
		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
	}

	if (dev->max_queue_pairs > 1) {
		if (!(dev->features & VHOST_USER_MQ)) {
			PMD_INIT_LOG(ERR, "MQ not supported by the backend");
			return -1;
		}
	}

	return 0;
}

void
virtio_user_dev_uninit(struct virtio_user_dev *dev)
{
	close(dev->vhostfd);
}

static uint8_t
virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs)
{
	uint16_t i;
	uint8_t ret = 0;

	if (q_pairs > dev->max_queue_pairs) {
		PMD_INIT_LOG(ERR, "multi-q config %u, but only %u supported",
			     q_pairs, dev->max_queue_pairs);
		return -1;
	}

	for (i = 0; i < q_pairs; ++i)
		ret |= vhost_user_enable_queue_pair(dev->vhostfd, i, 1);
	for (i = q_pairs; i < dev->max_queue_pairs; ++i)
		ret |= vhost_user_enable_queue_pair(dev->vhostfd, i, 0);

	dev->queue_pairs = q_pairs;

	return ret;
}

static uint32_t
virtio_user_handle_ctrl_msg(struct virtio_user_dev *dev, struct vring *vring,
			    uint16_t idx_hdr)
{
	struct virtio_net_ctrl_hdr *hdr;
	virtio_net_ctrl_ack status = ~0;
	uint16_t i, idx_data, idx_status;
	uint32_t n_descs = 0;

	/* locate desc for header, data, and status */
	idx_data = vring->desc[idx_hdr].next;
	n_descs++;

	i = idx_data;
	while (vring->desc[i].flags == VRING_DESC_F_NEXT) {
		i = vring->desc[i].next;
		n_descs++;
	}

	/* locate desc for status */
	idx_status = i;
	n_descs++;

	hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
	if (hdr->class == VIRTIO_NET_CTRL_MQ &&
	    hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
		uint16_t queues;

		queues = *(uint16_t *)(uintptr_t)vring->desc[idx_data].addr;
		status = virtio_user_handle_mq(dev, queues);
	}

	/* Update status */
	*(virtio_net_ctrl_ack *)(uintptr_t)vring->desc[idx_status].addr = status;

	return n_descs;
}

void
virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
{
	uint16_t avail_idx, desc_idx;
	struct vring_used_elem *uep;
	uint32_t n_descs;
	struct vring *vring = &dev->vrings[queue_idx];

	/* Consume avail ring, using used ring idx as first one */
	while (vring->used->idx != vring->avail->idx) {
		avail_idx = (vring->used->idx) & (vring->num - 1);
		desc_idx = vring->avail->ring[avail_idx];

		n_descs = virtio_user_handle_ctrl_msg(dev, vring, desc_idx);

		/* Update used ring */
		uep = &vring->used->ring[avail_idx];
		uep->id = avail_idx;
		uep->len = n_descs;

		vring->used->idx++;
	}
}