/*
 * VARCem	Virtual ARchaeological Computer EMulator.
 *		An emulator of (mostly) x86-based PC systems and devices,
 *		using the ISA,EISA,VLB,MCA  and PCI system buses, roughly
 *		spanning the era between 1981 and 1995.
 *
 *		This file is part of the VARCem Project.
 *
 *		Implementation of the network module.
 *
 * NOTE		The definition of the netcard_t is currently not optimal;
 *		it should be malloc'ed and then linked to the NETCARD def.
 *		Will be done later.
 *
 *
 *
 * Author:	Fred N. van Kempen, <decwiz@yahoo.com>
 *
 *		Copyright 2017-2019 Fred N. van Kempen.
 *
 *		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 entire
 *		   above 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.
 *
 *		3. Neither the  name of the copyright holder 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
 * HOLDER 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 <stdarg.h>
#include <stdatomic.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <wchar.h>
#include <time.h>
#include <stdbool.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include <86box/device.h>
#include <86box/timer.h>
#include <86box/plat.h>
#include <86box/thread.h>
#include <86box/ui.h>
#include <86box/timer.h>
#include <86box/network.h>
#include <86box/net_3c503.h>
#include <86box/net_ne2000.h>
#include <86box/net_pcnet.h>
#include <86box/net_plip.h>
#include <86box/net_wd8003.h>

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#endif

static const device_t net_none_device = {
    .name = "None",
    .internal_name = "none",
    .flags = 0,
    .local = NET_TYPE_NONE,
    .init = NULL,
    .close = NULL,
    .reset = NULL,
    { .available = NULL },
    .speed_changed = NULL,
    .force_redraw = NULL,
    .config = NULL
};


static const device_t *net_cards[] = {
    &net_none_device,
    &threec503_device,
    &pcnet_am79c960_device,
    &pcnet_am79c961_device,
    &ne1000_device,
    &ne2000_device,
    &pcnet_am79c960_eb_device,
    &rtl8019as_device,
    &wd8003e_device,
    &wd8003eb_device,
    &wd8013ebt_device,
    &plip_device,
    &ethernext_mc_device,
    &wd8003eta_device,
    &wd8003ea_device,
    &wd8013epa_device,
    &pcnet_am79c973_device,
    &pcnet_am79c970a_device,
    &rtl8029as_device,
    &pcnet_am79c960_vlb_device,
    NULL
};

netcard_conf_t net_cards_conf[NET_CARD_MAX];
int net_card_current = 0;

/* Global variables. */
int		network_ndev;
netdev_t	network_devs[NET_HOST_INTF_MAX];


/* Local variables. */

#ifdef ENABLE_NETWORK_LOG
int network_do_log = ENABLE_NETWORK_LOG;
static FILE *network_dump = NULL;
static mutex_t *network_dump_mutex;


static void
network_log(const char *fmt, ...)
{
    va_list ap;

    if (network_do_log) {
	va_start(ap, fmt);
	pclog_ex(fmt, ap);
	va_end(ap);
    }
}


static void
network_dump_packet(netpkt_t *pkt)
{
    if (!network_dump)
	return;

    struct timeval tv;
    gettimeofday(&tv, NULL);
    struct {
	uint32_t ts_sec, ts_usec, incl_len, orig_len;
    } pcap_packet_hdr = {
	tv.tv_sec, tv.tv_usec, pkt->len, pkt->len
    };

    if (network_dump_mutex)
	thread_wait_mutex(network_dump_mutex);

    size_t written;
    if ((written = fwrite(&pcap_packet_hdr, 1, sizeof(pcap_packet_hdr), network_dump)) < sizeof(pcap_packet_hdr)) {
	network_log("NETWORK: failed to write dump packet header\n");
	fseek(network_dump, -written, SEEK_CUR);
    } else {
	if ((written = fwrite(pkt->data, 1, pkt->len, network_dump)) < pkt->len) {
		network_log("NETWORK: failed to write dump packet data\n");
		fseek(network_dump, -written - sizeof(pcap_packet_hdr), SEEK_CUR);
	}
	fflush(network_dump);
    }

    if (network_dump_mutex)
	thread_release_mutex(network_dump_mutex);
}
#else
#define network_log(fmt, ...)
#define network_dump_packet(pkt)
#endif


#ifdef _WIN32
static void
network_winsock_clean(void)
{
    WSACleanup();
}
#endif

/*
 * Initialize the configured network cards.
 *
 * This function gets called only once, from the System
 * Platform initialization code (currently in pc.c) to
 * set our local stuff to a known state.
 */
void
network_init(void)
{
    int i;

#ifdef _WIN32
    WSADATA Data;
    WSAStartup(MAKEWORD(2, 0), &Data);
    atexit(network_winsock_clean);
#endif

    /* Create a first device entry that's always there, as needed by UI. */
    strcpy(network_devs[0].device, "none");
    strcpy(network_devs[0].description, "None");
    network_ndev = 1;

    /* Initialize the Pcap system module, if present. */
    i = net_pcap_prepare(&network_devs[network_ndev]);
    if (i > 0)
	network_ndev += i;

#ifdef ENABLE_NETWORK_LOG
    /* Start packet dump. */
    network_dump = fopen("network.pcap", "wb");

    struct {
	uint32_t magic_number;
	uint16_t version_major, version_minor;
	int32_t	 thiszone;
	uint32_t sigfigs, snaplen, network;
    } pcap_hdr = {
	0xa1b2c3d4,
	2, 4,
	0,
	0, 65535, 1
    };
    fwrite(&pcap_hdr, sizeof(pcap_hdr), 1, network_dump);
    fflush(network_dump);
#endif
}

static void
network_queue_init(netqueue_t *queue)
{
    queue->size = NET_QUEUE_LEN;
    queue->head = queue->tail = 0;
    for (int i=0; i<queue->size; i++) {
        queue->packets[i].data = calloc(1, NET_MAX_FRAME);
        queue->packets[i].len = 0;
    }

}

static bool
network_queue_full(netqueue_t *queue)
{
    return ((queue->head + 1) % queue->size) == queue->tail;
}

static bool
network_queue_empty(netqueue_t *queue)
{
    return (queue->head == queue->tail);
}

int
network_queue_put(netqueue_t *queue, uint8_t *data, int len)
{
    if (len > NET_MAX_FRAME || network_queue_full(queue)) {
        return 0;
    }

    netpkt_t *pkt = &queue->packets[queue->head];
    memcpy(pkt->data, data, len);
    pkt->len = len;
    queue->head = (queue->head + 1) % queue->size;
    return 1;
}

static int
network_queue_get(netqueue_t *queue, netpkt_t *dst_pkt) {
    if (network_queue_empty(queue))
        return 0;

    netpkt_t *pkt = &queue->packets[queue->tail];
    memcpy(dst_pkt->data, pkt->data, pkt->len);
    dst_pkt->len = pkt->len;
    queue->tail = (queue->tail + 1) % queue->size;

    return 1;
}

static int
network_queue_move(netqueue_t *dst_q, netqueue_t *src_q)
{
    if (network_queue_empty(src_q))
        return 0;

    if (network_queue_full(dst_q)) {
        return 0;
    }

    netpkt_t *src_pkt = &src_q->packets[src_q->tail];
    netpkt_t *dst_pkt = &dst_q->packets[dst_q->head];
    uint8_t *tmp_dat = dst_pkt->data;

    dst_pkt->data = src_pkt->data;
    dst_pkt->len = src_pkt->len;
    dst_q->head = (dst_q->head + 1) % dst_q->size;

    src_pkt->data = tmp_dat;
    src_pkt->len = 0;
    src_q->tail = (src_q->tail + 1) % src_q->size;

    return 1;
}

static void
network_queue_clear(netqueue_t *queue)
{
    for (int i=0; i<queue->size; i++) {
        free(queue->packets[i].data);
        queue->packets[i].len = 0;
    }
    queue->tail = queue->head = 0;
}


static void
network_rx_queue(void *priv)
{
    netcard_t *card = (netcard_t *)priv;
    double timer_period;
    int ret = 0;

    bool activity = false;

    if (card->queued_pkt.len == 0) {
        thread_wait_mutex(card->rx_mutex);
        network_queue_get(&card->queues[NET_QUEUE_RX], &card->queued_pkt);
        thread_release_mutex(card->rx_mutex);
    }

    if (card->queued_pkt.len > 0) {
        network_dump_packet(&card->queued_pkt);
        ret = card->rx(card->card_drv, card->queued_pkt.data, card->queued_pkt.len);
    }

    if (ret) {
        activity = true;
        timer_period = 0.762939453125 * ((card->queued_pkt.len >= 128) ? ((double) card->queued_pkt.len) : 128.0);
        card->queued_pkt.len = 0;
    } else {
        timer_period = 0.762939453125 * 128.0;
    }
    timer_on_auto(&card->timer, timer_period);

    /* Transmission. */
    thread_wait_mutex(card->tx_mutex);
    ret = network_queue_move(&card->queues[NET_QUEUE_TX_HOST], &card->queues[NET_QUEUE_TX_VM]);
    thread_release_mutex(card->tx_mutex);
    if (ret) {
        /* Notify host that a packet is available in the TX queue */
        card->host_drv.notify_in(card->host_drv.priv);
        activity = true;
    }

    ui_sb_update_icon(SB_NETWORK, activity);
}


/*
 * Attach a network card to the system.
 *
 * This function is called by a hardware driver ("card") after it has
 * finished initializing itself, to link itself to the platform support
 * modules.
 */
netcard_t *
network_attach(void *card_drv, uint8_t *mac, NETRXCB rx, NETWAITCB wait, NETSETLINKSTATE set_link_state)
{
    netcard_t *card = calloc(1, sizeof(netcard_t));
    card->queued_pkt.data = calloc(1, NET_MAX_FRAME);
    card->card_drv = card_drv;
    card->rx = rx;
    card->wait = wait;
    card->set_link_state = set_link_state;
    card->tx_mutex = thread_create_mutex();
    card->rx_mutex = thread_create_mutex();

    for (int i=0; i<3; i++) {
        network_queue_init(&card->queues[i]);
    }

    switch (net_cards_conf[net_card_current].net_type) {
        case NET_TYPE_SLIRP:
        default:
            card->host_drv = net_slirp_drv;
            card->host_drv.priv = card->host_drv.init(card, mac, NULL);
            break;

        case NET_TYPE_PCAP:
            card->host_drv = net_pcap_drv;
            card->host_drv.priv = card->host_drv.init(card, mac, net_cards_conf[net_card_current].host_dev_name);
            break;
    }

    if (!card->host_drv.priv) {
        thread_close_mutex(card->tx_mutex);
        thread_close_mutex(card->rx_mutex);
        for (int i=0; i<3; i++) {
            network_queue_clear(&card->queues[i]);
        }

        free(card->queued_pkt.data);
        free(card);
        return NULL;
    }

    timer_add(&card->timer, network_rx_queue, card, 0);
    timer_on_auto(&card->timer, 0.762939453125 * 2.0);

    return card;
}

void
netcard_close(netcard_t *card)
{
    timer_stop(&card->timer);
    card->host_drv.close(card->host_drv.priv);

    thread_close_mutex(card->tx_mutex);
    thread_close_mutex(card->rx_mutex);
    for (int i=0; i<3; i++) {
        network_queue_clear(&card->queues[i]);
    }

    free(card->queued_pkt.data);
    free(card);
}


/* Stop any network activity. */
void
network_close(void)
{
#ifdef ENABLE_NETWORK_LOG
    thread_close_mutex(network_dump_mutex);
    network_dump_mutex = NULL;
#endif

    network_log("NETWORK: closed.\n");
}


/*
 * Reset the network card(s).
 *
 * This function is called each time the system is reset,
 * either a hard reset (including power-up) or a soft reset
 * including C-A-D reset.)  It is responsible for connecting
 * everything together.
 */
void
network_reset(void)
{
    int i = -1;

    ui_sb_update_icon(SB_NETWORK, 0);

#ifdef ENABLE_NETWORK_LOG
    network_dump_mutex = thread_create_mutex();
#endif

    for (i = 0; i < NET_CARD_MAX; i++) {
            if (!net_cards_conf[i].device_num || net_cards_conf[i].net_type == NET_TYPE_NONE || 
                (net_cards_conf[i].net_type == NET_TYPE_PCAP && !strcmp(net_cards_conf[i].host_dev_name, "none"))) {
                continue;
            }

            net_card_current = i;
            device_add_inst(net_cards[net_cards_conf[i].device_num], i + 1);
    }
}


/* Queue a packet for transmission to one of the network providers. */
void
network_tx(netcard_t *card, uint8_t *bufp, int len)
{
    network_queue_put(&card->queues[NET_QUEUE_TX_VM], bufp, len);
}

int network_tx_pop(netcard_t *card, netpkt_t *out_pkt)
{
    int ret = 0;

    thread_wait_mutex(card->tx_mutex);
    ret = network_queue_get(&card->queues[NET_QUEUE_TX_HOST], out_pkt);
    thread_release_mutex(card->tx_mutex);

    return ret;
}

int network_rx_put(netcard_t *card, uint8_t *bufp, int len)
{
    int ret = 0;

    thread_wait_mutex(card->rx_mutex);
    ret = network_queue_put(&card->queues[NET_QUEUE_RX], bufp, len);
    thread_release_mutex(card->rx_mutex);

    return ret;
}

int
network_dev_to_id(char *devname)
{
    int i = 0;

    for (i=0; i<network_ndev; i++) {
	if (! strcmp((char *)network_devs[i].device, devname)) {
		return(i);
	}
    }

    /* If no match found, assume "none". */
    return(0);
}


/* UI */
int
network_available(void)
{
    int available = 0;

    for (int i = 0; i < NET_CARD_MAX; i ++) {
        available |= (net_cards_conf[i].device_num > 0) && (net_cards_conf[i].net_type != NET_TYPE_NONE);
    }

    return available;
}


/* UI */
int
network_card_available(int card)
{
    if (net_cards[card])
	return(device_available(net_cards[card]));

    return(1);
}


/* UI */
const device_t *
network_card_getdevice(int card)
{
    return(net_cards[card]);
}


/* UI */
int
network_card_has_config(int card)
{
    if (!net_cards[card]) return(0);

    return(device_has_config(net_cards[card]) ? 1 : 0);
}


/* UI */
char *
network_card_get_internal_name(int card)
{
    return device_get_internal_name(net_cards[card]);
}


/* UI */
int
network_card_get_from_internal_name(char *s)
{
    int c = 0;

    while (net_cards[c] != NULL) {
	if (! strcmp((char *)net_cards[c]->internal_name, s))
		return(c);
	c++;
    }

    return 0;
}