/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 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 <rte_eal.h>

#include <rte_common.h>
#include <rte_debug.h>
#include <rte_errno.h>
#include <rte_ethdev.h>
#include <rte_launch.h>
#include <rte_lcore.h>
#include <rte_log.h>
#include <rte_mbuf.h>
#include <rte_ring.h>

#include <rte_byteorder.h>

#include "args.h"
#include "main.h"
#include "init.h"
#include "../include/conf.h"


#ifdef QW_SOFTWARE_FC
#define SEND_PAUSE_FRAME(port_id, duration) send_pause_frame(port_id, duration)
#else
#define SEND_PAUSE_FRAME(port_id, duration) do { } while(0)
#endif

#define ETHER_TYPE_FLOW_CONTROL 0x8808

struct ether_fc_frame {
	uint16_t opcode;
	uint16_t param;
} __attribute__((__packed__));


int *quota;
unsigned int *low_watermark;
unsigned int *high_watermark;

uint16_t port_pairs[RTE_MAX_ETHPORTS];

struct rte_ring *rings[RTE_MAX_LCORE][RTE_MAX_ETHPORTS];
struct rte_mempool *mbuf_pool;


static void send_pause_frame(uint16_t port_id, uint16_t duration)
{
	struct rte_mbuf *mbuf;
	struct ether_fc_frame *pause_frame;
	struct ether_hdr *hdr;
	struct ether_addr mac_addr;

	RTE_LOG_DP(DEBUG, USER1,
			"Sending PAUSE frame (duration=%d) on port %d\n",
			duration, port_id);

	/* Get a mbuf from the pool */
	mbuf = rte_pktmbuf_alloc(mbuf_pool);
	if (unlikely(mbuf == NULL))
		return;

	/* Prepare a PAUSE frame */
	hdr = rte_pktmbuf_mtod(mbuf, struct ether_hdr *);
	pause_frame = (struct ether_fc_frame *) &hdr[1];

	rte_eth_macaddr_get(port_id, &mac_addr);
	ether_addr_copy(&mac_addr, &hdr->s_addr);

	void *tmp = &hdr->d_addr.addr_bytes[0];
	*((uint64_t *)tmp) = 0x010000C28001ULL;

	hdr->ether_type = rte_cpu_to_be_16(ETHER_TYPE_FLOW_CONTROL);

	pause_frame->opcode = rte_cpu_to_be_16(0x0001);
	pause_frame->param  = rte_cpu_to_be_16(duration);

	mbuf->pkt_len  = 60;
	mbuf->data_len = 60;

	rte_eth_tx_burst(port_id, 0, &mbuf, 1);
}

/**
 * Get the previous enabled lcore ID
 *
 * @param lcore_id
 *   The current lcore ID.
 * @return
 *   The previous enabled lcore_id or -1 if not found.
 */
static unsigned int
get_previous_lcore_id(unsigned int lcore_id)
{
	int i;

	for (i = lcore_id - 1; i >= 0; i--)
		if (rte_lcore_is_enabled(i))
			return i;

	return -1;
}

/**
 * Get the last enabled lcore ID
 *
 * @return
 *   The last enabled lcore_id.
 */
static unsigned int
get_last_lcore_id(void)
{
	int i;

	for (i = RTE_MAX_LCORE; i >= 0; i--)
		if (rte_lcore_is_enabled(i))
			return i;

	return 0;
}

static void
receive_stage(__attribute__((unused)) void *args)
{
	int i, ret;

	uint16_t port_id;
	uint16_t nb_rx_pkts;

	unsigned int lcore_id;
	unsigned int free;

	struct rte_mbuf *pkts[MAX_PKT_QUOTA];
	struct rte_ring *ring;
	enum ring_state ring_state[RTE_MAX_ETHPORTS] = { RING_READY };

	lcore_id = rte_lcore_id();

	RTE_LOG(INFO, USER1,
			"%s() started on core %u\n", __func__, lcore_id);

	while (1) {

		/* Process each port round robin style */
		for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++) {

			if (!is_bit_set(port_id, portmask))
				continue;

			ring = rings[lcore_id][port_id];

			if (ring_state[port_id] != RING_READY) {
				if (rte_ring_count(ring) > *low_watermark)
					continue;
				else
					ring_state[port_id] = RING_READY;
			}

			/* Enqueue received packets on the RX ring */
			nb_rx_pkts = rte_eth_rx_burst(port_id, 0, pkts,
					(uint16_t) *quota);
			ret = rte_ring_enqueue_bulk(ring, (void *) pkts,
					nb_rx_pkts, &free);
			if (RING_SIZE - free > *high_watermark) {
				ring_state[port_id] = RING_OVERLOADED;
				send_pause_frame(port_id, 1337);
			}

			if (ret == 0) {

				/*
				 * Return  mbufs to the pool,
				 * effectively dropping packets
				 */
				for (i = 0; i < nb_rx_pkts; i++)
					rte_pktmbuf_free(pkts[i]);
			}
		}
	}
}

static int
pipeline_stage(__attribute__((unused)) void *args)
{
	int i, ret;
	int nb_dq_pkts;

	uint16_t port_id;

	unsigned int lcore_id, previous_lcore_id;
	unsigned int free;

	void *pkts[MAX_PKT_QUOTA];
	struct rte_ring *rx, *tx;
	enum ring_state ring_state[RTE_MAX_ETHPORTS] = { RING_READY };

	lcore_id = rte_lcore_id();
	previous_lcore_id = get_previous_lcore_id(lcore_id);

	RTE_LOG(INFO, USER1,
			"%s() started on core %u - processing packets from core %u\n",
			__func__, lcore_id, previous_lcore_id);

	while (1) {

		for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++) {

			if (!is_bit_set(port_id, portmask))
				continue;

			tx = rings[lcore_id][port_id];
			rx = rings[previous_lcore_id][port_id];

			if (ring_state[port_id] != RING_READY) {
				if (rte_ring_count(tx) > *low_watermark)
					continue;
				else
					ring_state[port_id] = RING_READY;
			}

			/* Dequeue up to quota mbuf from rx */
			nb_dq_pkts = rte_ring_dequeue_burst(rx, pkts,
					*quota, NULL);
			if (unlikely(nb_dq_pkts < 0))
				continue;

			/* Enqueue them on tx */
			ret = rte_ring_enqueue_bulk(tx, pkts,
					nb_dq_pkts, &free);
			if (RING_SIZE - free > *high_watermark)
				ring_state[port_id] = RING_OVERLOADED;

			if (ret == 0) {

				/*
				 * Return  mbufs to the pool,
				 * effectively dropping packets
				 */
				for (i = 0; i < nb_dq_pkts; i++)
					rte_pktmbuf_free(pkts[i]);
			}
		}
	}

	return 0;
}

static int
send_stage(__attribute__((unused)) void *args)
{
	uint16_t nb_dq_pkts;

	uint16_t port_id;
	uint16_t dest_port_id;

	unsigned int lcore_id, previous_lcore_id;

	struct rte_ring *tx;
	struct rte_mbuf *tx_pkts[MAX_PKT_QUOTA];

	lcore_id = rte_lcore_id();
	previous_lcore_id = get_previous_lcore_id(lcore_id);

	RTE_LOG(INFO, USER1,
			"%s() started on core %u - processing packets from core %u\n",
			__func__, lcore_id, previous_lcore_id);

	while (1) {

		/* Process each ring round robin style */
		for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++) {

			if (!is_bit_set(port_id, portmask))
				continue;

			dest_port_id = port_pairs[port_id];
			tx = rings[previous_lcore_id][port_id];

			if (rte_ring_empty(tx))
				continue;

			/* Dequeue packets from tx and send them */
			nb_dq_pkts = (uint16_t) rte_ring_dequeue_burst(tx,
					(void *) tx_pkts, *quota, NULL);
			rte_eth_tx_burst(dest_port_id, 0, tx_pkts, nb_dq_pkts);

			/* TODO: Check if nb_dq_pkts == nb_tx_pkts? */
		}
	}

	return 0;
}

int
main(int argc, char **argv)
{
	int ret;
	unsigned int lcore_id, master_lcore_id, last_lcore_id;

	uint16_t port_id;

	rte_log_set_global_level(RTE_LOG_INFO);

	ret = rte_eal_init(argc, argv);
	if (ret < 0)
		rte_exit(EXIT_FAILURE, "Cannot initialize EAL\n");

	argc -= ret;
	argv += ret;

	init_dpdk();
	setup_shared_variables();

	*quota = 32;
	*low_watermark = 60 * RING_SIZE / 100;

	last_lcore_id   = get_last_lcore_id();
	master_lcore_id = rte_get_master_lcore();

	/* Parse the application's arguments */
	ret = parse_qw_args(argc, argv);
	if (ret < 0)
		rte_exit(EXIT_FAILURE, "Invalid quota/watermark argument(s)\n");

	/* Create a pool of mbuf to store packets */
	mbuf_pool = rte_pktmbuf_pool_create("mbuf_pool", MBUF_PER_POOL, 32, 0,
			MBUF_DATA_SIZE, rte_socket_id());
	if (mbuf_pool == NULL)
		rte_panic("%s\n", rte_strerror(rte_errno));

	for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++)
		if (is_bit_set(port_id, portmask)) {
			configure_eth_port(port_id);
			init_ring(master_lcore_id, port_id);
		}

	pair_ports();

	/*
	 * Start pipeline_connect() on all the available slave lcores
	 * but the last
	 */
	for (lcore_id = 0 ; lcore_id < last_lcore_id; lcore_id++) {
		if (rte_lcore_is_enabled(lcore_id) &&
				lcore_id != master_lcore_id) {

			for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++)
				if (is_bit_set(port_id, portmask))
					init_ring(lcore_id, port_id);

			rte_eal_remote_launch(pipeline_stage,
					NULL, lcore_id);
		}
	}

	/* Start send_stage() on the last slave core */
	rte_eal_remote_launch(send_stage, NULL, last_lcore_id);

	/* Start receive_stage() on the master core */
	receive_stage(NULL);

	return 0;
}