/*
 * rawnetarch.c - raw ethernet interface,
 *                 architecture-dependant stuff
 *
 * Written by
 *  Spiro Trikaliotis <Spiro.Trikaliotis@gmx.de>
 * 
 * This file is part of VICE, the Versatile Commodore Emulator.
 * See README for copyright notice.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307  USA.
 *
 */

#include "vice.h"

#ifdef HAVE_PCAP 

/* #define WPCAP */

#include "pcap.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lib.h"
#include "log.h"
#include "rawnet.h"
#include "rawnetarch.h"

typedef pcap_t *(*pcap_open_live_t)(const char *, int, int, int, char *);
typedef int (*pcap_dispatch_t)(pcap_t *, int, pcap_handler, u_char *);
typedef int (*pcap_setnonblock_t)(pcap_t *, int, char *);
typedef int (*pcap_datalink_t)(pcap_t *);
typedef int (*pcap_findalldevs_t)(pcap_if_t **, char *);
typedef void (*pcap_freealldevs_t)(pcap_if_t *);
typedef int (*pcap_sendpacket_t)(pcap_t *p, u_char *buf, int size);
typedef char *(*pcap_lookupdev_t)(char *);

/** #define RAWNET_DEBUG_ARCH 1 **/
/** #define RAWNET_DEBUG_PKTDUMP 1 **/

/* #define RAWNET_DEBUG_FRAMES - might be defined in rawnetarch.h ! */

#define RAWNET_DEBUG_WARN 1 /* this should not be deactivated */

static pcap_open_live_t p_pcap_open_live;
static pcap_dispatch_t p_pcap_dispatch;
static pcap_setnonblock_t p_pcap_setnonblock;
static pcap_findalldevs_t p_pcap_findalldevs;
static pcap_freealldevs_t p_pcap_freealldevs;
static pcap_sendpacket_t p_pcap_sendpacket;
static pcap_datalink_t p_pcap_datalink;
static pcap_lookupdev_t p_pcap_lookupdev;

static HINSTANCE pcap_library = NULL;

/* ------------------------------------------------------------------------- */
/*    variables needed                                                       */

static log_t rawnet_arch_log = LOG_ERR;

static pcap_if_t *EthernetPcapNextDev = NULL;
static pcap_if_t *EthernetPcapAlldevs = NULL;
static pcap_t *EthernetPcapFP = NULL;

static char EthernetPcapErrbuf[PCAP_ERRBUF_SIZE];

#ifdef RAWNET_DEBUG_PKTDUMP

static void debug_output(const char *text, BYTE *what, int count)
{
    char buffer[256];
    char *p = buffer;
    char *pbuffer1 = what;
    int len1 = count;
    int i;

    sprintf(buffer, "\n%s: length = %u\n", text, len1);
    OutputDebugString(buffer);
    do {
        p = buffer;
        for (i = 0; (i < 8) && len1 > 0; len1--, i++) {
            sprintf( p, "%02x ", (unsigned int)(unsigned char)*pbuffer1++);
            p += 3;
        }
        *(p - 1) = '\n';
        *p = 0;
        OutputDebugString(buffer);
    } while (len1 > 0);
}
#endif /* #ifdef RAWNET_DEBUG_PKTDUMP */


static void EthernetPcapFreeLibrary(void)
{
    if (pcap_library) {
        if (!FreeLibrary(pcap_library)) {
            log_message(rawnet_arch_log, "FreeLibrary WPCAP.DLL failed!");
        }
        pcap_library = NULL;

        p_pcap_open_live = NULL;
        p_pcap_dispatch = NULL;
        p_pcap_setnonblock = NULL;
        p_pcap_findalldevs = NULL;
        p_pcap_freealldevs = NULL;
        p_pcap_sendpacket = NULL;
        p_pcap_datalink = NULL;
        p_pcap_lookupdev = NULL;
    }
}

/* since I don't like typing too much... */
#define GET_PROC_ADDRESS_AND_TEST( _name_ )                              \
    p_##_name_ = (_name_##_t) GetProcAddress(pcap_library, #_name_);     \
    if (!p_##_name_ ) {                                                  \
        log_message(rawnet_arch_log, "GetProcAddress " #_name_ " failed!"); \
        EthernetPcapFreeLibrary();                                            \
        return FALSE;                                                    \
    } 

static BOOL EthernetPcapLoadLibrary(void)
{
    if (!pcap_library) {
        pcap_library = LoadLibrary(TEXT("wpcap.dll"));

        if (!pcap_library) {
            log_message(rawnet_arch_log, "LoadLibrary WPCAP.DLL failed!");
            return FALSE;
        }

        GET_PROC_ADDRESS_AND_TEST(pcap_open_live);
        GET_PROC_ADDRESS_AND_TEST(pcap_dispatch);
        GET_PROC_ADDRESS_AND_TEST(pcap_setnonblock);
        GET_PROC_ADDRESS_AND_TEST(pcap_findalldevs);
        GET_PROC_ADDRESS_AND_TEST(pcap_freealldevs);
        GET_PROC_ADDRESS_AND_TEST(pcap_sendpacket);
        GET_PROC_ADDRESS_AND_TEST(pcap_datalink);
        GET_PROC_ADDRESS_AND_TEST(pcap_lookupdev);
    }

    return TRUE;
}

#undef GET_PROC_ADDRESS_AND_TEST


/*
 These functions let the UI enumerate the available interfaces.

 First, rawnet_arch_enumadapter_open() is used to start enumeration.

 rawnet_arch_enumadapter is then used to gather information for each adapter present
 on the system, where:

   ppname points to a pointer which will hold the name of the interface
   ppdescription points to a pointer which will hold the description of the interface

   For each of these parameters, new memory is allocated, so it has to be
   freed with lib_free().

 rawnet_arch_enumadapter_close() must be used to stop processing.

 Each function returns 1 on success, and 0 on failure.
 rawnet_arch_enumadapter() only fails if there is no more adpater; in this case,
   *ppname and *ppdescription are not altered.
*/
int rawnet_arch_enumadapter_open(void)
{
    if (!EthernetPcapLoadLibrary()) {
        return 0;
    }

    if ((*p_pcap_findalldevs)(&EthernetPcapAlldevs, EthernetPcapErrbuf) == -1) {
        log_message(rawnet_arch_log, "ERROR in rawnet_arch_enumadapter_open: pcap_findalldevs: '%s'", EthernetPcapErrbuf);
        return 0;
    }

    if (!EthernetPcapAlldevs) {
        log_message(rawnet_arch_log, "ERROR in rawnet_arch_enumadapter_open, finding all pcap devices - Do we have the necessary privilege rights?");
        return 0;
    }

    EthernetPcapNextDev = EthernetPcapAlldevs;

    return 1;
}

int rawnet_arch_enumadapter(char **ppname, char **ppdescription)
{
    if (!EthernetPcapNextDev) {
        return 0;
    }

    *ppname = lib_stralloc(EthernetPcapNextDev->name);
    *ppdescription = lib_stralloc(EthernetPcapNextDev->description);

    EthernetPcapNextDev = EthernetPcapNextDev->next;

    return 1;
}

int rawnet_arch_enumadapter_close(void)
{
    if (EthernetPcapAlldevs) {
        (*p_pcap_freealldevs)(EthernetPcapAlldevs);
        EthernetPcapAlldevs = NULL;
    }
    return 1;
}

static BOOL EthernetPcapOpenAdapter(const char *interface_name) 
{
    pcap_if_t *EthernetPcapDevice = NULL;

    if (!rawnet_enumadapter_open()) {
        return FALSE;
    } else {
        /* look if we can find the specified adapter */
        char *pname;
        char *pdescription;
        BOOL  found = FALSE;

        if (interface_name) {
            /* we have an interface name, try it */
            EthernetPcapDevice = EthernetPcapAlldevs;

            while (rawnet_enumadapter(&pname, &pdescription)) {
                if (strcmp(pname, interface_name) == 0) {
                    found = TRUE;
                }
                lib_free(pname);
                lib_free(pdescription);
                if (found) break;
                EthernetPcapDevice = EthernetPcapNextDev;
            }
        }

        if (!found) {
            /* just take the first adapter */
            EthernetPcapDevice = EthernetPcapAlldevs;
        }
    }

    EthernetPcapFP = (*p_pcap_open_live)(EthernetPcapDevice->name, 1700, 1, 20, EthernetPcapErrbuf);
    if (EthernetPcapFP == NULL) {
        log_message(rawnet_arch_log, "ERROR opening adapter: '%s'", EthernetPcapErrbuf);
        rawnet_enumadapter_close();
        return FALSE;
    }

    if ((*p_pcap_setnonblock)(EthernetPcapFP, 1, EthernetPcapErrbuf) < 0) {
        log_message(rawnet_arch_log, "WARNING: Setting PCAP to non-blocking failed: '%s'", EthernetPcapErrbuf);
    }

    /* Check the link layer. We support only Ethernet for simplicity. */
    if ((*p_pcap_datalink)(EthernetPcapFP) != DLT_EN10MB) {
        log_message(rawnet_arch_log, "ERROR: Ethernet works only on Ethernet networks.");
        rawnet_enumadapter_close();
        return FALSE;
    }

    rawnet_enumadapter_close();
    return TRUE;
}

/* ------------------------------------------------------------------------- */
/*    the architecture-dependend functions                                   */

int rawnet_arch_init(void)
{
    rawnet_arch_log = log_open("EthernetARCH");

    if (!EthernetPcapLoadLibrary()) {
        return 0;
    }

    return 1;
}

void rawnet_arch_pre_reset( void )
{
#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_pre_reset().");
#endif
}

void rawnet_arch_post_reset( void )
{
#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_post_reset().");
#endif
}

int rawnet_arch_activate(const char *interface_name)
{
#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_activate().");
#endif
    if (!EthernetPcapOpenAdapter(interface_name)) {
        return 0;
    }
    return 1;
}

void rawnet_arch_deactivate( void )
{
#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_deactivate().");
#endif
}

void rawnet_arch_set_mac( const BYTE mac[6] )
{
#if defined(RAWNET_DEBUG_ARCH) || defined(RAWNET_DEBUG_FRAMES)
    log_message(rawnet_arch_log, "New MAC address set: %02X:%02X:%02X:%02X:%02X:%02X.", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
#endif
}

void rawnet_arch_set_hashfilter(const DWORD hash_mask[2])
{
#if defined(RAWNET_DEBUG_ARCH) || defined(RAWNET_DEBUG_FRAMES)
    log_message(rawnet_arch_log, "New hash filter set: %08X:%08X.", hash_mask[1], hash_mask[0]);
#endif
}

/* int bBroadcast   - broadcast */
/* int bIA          - individual address (IA) */
/* int bMulticast   - multicast if address passes the hash filter */
/* int bCorrect     - accept correct frames */
/* int bPromiscuous - promiscuous mode */
/* int bIAHash      - accept if IA passes the hash filter */


void rawnet_arch_recv_ctl(int bBroadcast, int bIA, int bMulticast, int bCorrect, int bPromiscuous, int bIAHash)
{
#if defined(RAWNET_DEBUG_ARCH) || defined(RAWNET_DEBUG_FRAMES)
    log_message(rawnet_arch_log, "rawnet_arch_recv_ctl() called with the following parameters:" );
    log_message(rawnet_arch_log, "\tbBroadcast   = %s", bBroadcast ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbIA          = %s", bIA ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbMulticast   = %s", bMulticast ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbCorrect     = %s", bCorrect ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbPromiscuous = %s", bPromiscuous ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbIAHash      = %s", bIAHash ? "TRUE" : "FALSE" );
#endif
}

void rawnet_arch_line_ctl(int bEnableTransmitter, int bEnableReceiver)
{
#if defined(RAWNET_DEBUG_ARCH) || defined(RAWNET_DEBUG_FRAMES)
    log_message(rawnet_arch_log, "rawnet_arch_line_ctl() called with the following parameters:" );
    log_message(rawnet_arch_log, "\tbEnableTransmitter = %s", bEnableTransmitter ? "TRUE" : "FALSE" );
    log_message(rawnet_arch_log, "\tbEnableReceiver    = %s", bEnableReceiver ? "TRUE" : "FALSE" );
#endif
}

typedef struct Ethernet_PCAP_internal_s {
    unsigned int len;
    BYTE *buffer;
} Ethernet_PCAP_internal_t;

/* Callback function invoked by libpcap for every incoming packet */
static void EthernetPcapPacketHandler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data)
{
    Ethernet_PCAP_internal_t *pinternal = (void*)param;

    /* determine the count of bytes which has been returned, 
     * but make sure not to overrun the buffer 
     */
    if (header->caplen < pinternal->len) {
        pinternal->len = header->caplen;
    }

    memcpy(pinternal->buffer, pkt_data, pinternal->len);
}

/* the following function receives a frame.

   If there's none, it returns a -1.
   If there is one, it returns the length of the frame in bytes.

   It copies the frame to *buffer and returns the number of copied 
   bytes as return value.

   At most 'len' bytes are copied.
*/
static int rawnet_arch_receive_frame(Ethernet_PCAP_internal_t *pinternal)
{
    int ret = -1;

    /* check if there is something to receive */
    if ((*p_pcap_dispatch)(EthernetPcapFP, 1, EthernetPcapPacketHandler, (void*)pinternal) != 0) {
        /* Something has been received */
        ret = pinternal->len;
    }

#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_receive_frame() called, returns %d.", ret);
#endif

    return ret;
}

/* int force       - FORCE: Delete waiting frames in transmit buffer */
/* int onecoll     - ONECOLL: Terminate after just one collision */
/* int inhibit_crc - INHIBITCRC: Do not append CRC to the transmission */
/* int tx_pad_dis  - TXPADDIS: Disable padding to 60 Bytes */
/* int txlength    - Frame length */
/* BYTE *txframe   - Pointer to the frame to be transmitted */

void rawnet_arch_transmit(int force, int onecoll, int inhibit_crc, int tx_pad_dis, int txlength, BYTE *txframe)
{
#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_transmit() called, with: force = %s, onecoll = %s, inhibit_crc=%s, tx_pad_dis=%s, txlength=%u",
                force ? "TRUE" : "FALSE",
                onecoll ? "TRUE" : "FALSE",
                inhibit_crc ? "TRUE" : "FALSE",
                tx_pad_dis ?  "TRUE" : "FALSE",
                txlength);
#endif

#ifdef RAWNET_DEBUG_PKTDUMP
    debug_output("Transmit frame: ", txframe, txlength);
#endif /* #ifdef RAWNET_DEBUG_PKTDUMP */

    if ((*p_pcap_sendpacket)(EthernetPcapFP, txframe, txlength) == -1) {
        log_message(rawnet_arch_log, "WARNING! Could not send packet!");
    }
}

/*
  rawnet_arch_receive()

  This function checks if there was a frame received.
  If so, it returns 1, else 0.

  If there was no frame, none of the parameters is changed!

  If there was a frame, the following actions are done:

  - at maximum *plen byte are transferred into the buffer given by pbuffer
  - *plen gets the length of the received frame, EVEN if this is more
    than has been copied to pbuffer!
  - if the dest. address was accepted by the hash filter, *phashed is set, else
    cleared.
  - if the dest. address was accepted by the hash filter, *phash_index is
    set to the number of the rule leading to the acceptance
  - if the receive was ok (good CRC and valid length), *prx_ok is set, 
    else cleared.
  - if the dest. address was accepted because it's exactly our MAC address
    (set by rawnet_arch_set_mac()), *pcorrect_mac is set, else cleared.
  - if the dest. address was accepted since it was a broadcast address,
    *pbroadcast is set, else cleared.
  - if the received frame had a crc error, *pcrc_error is set, else cleared
*/

/* BYTE *pbuffer     - where to store a frame */
/* int *plen         - IN: maximum length of frame to copy; 
                       OUT: length of received frame 
                            OUT can be bigger than IN if received frame was
                            longer than supplied buffer */
/* int *phashed      - set if the dest. address is accepted by the hash filter */
/* int *phash_index  - hash table index if hashed == TRUE */
/* int *prx_ok       - set if good CRC and valid length */
/* int *pcorrect_mac - set if dest. address is exactly our IA */
/* int *pbroadcast   - set if dest. address is a broadcast address */
/* int *pcrc_error   - set if received frame had a CRC error */

int rawnet_arch_receive(BYTE *pbuffer, int *plen, int *phashed, int *phash_index, int *prx_ok, int *pcorrect_mac, int *pbroadcast, int *pcrc_error)
{
    int len;

    Ethernet_PCAP_internal_t internal;

    internal.len = *plen;
    internal.buffer = pbuffer;

#ifdef RAWNET_DEBUG_ARCH
    log_message(rawnet_arch_log, "rawnet_arch_receive() called, with *plen=%u.", *plen);
#endif

    assert((*plen & 1) == 0);

    len = rawnet_arch_receive_frame(&internal);

    if (len != -1) {

#ifdef RAWNET_DEBUG_PKTDUMP
        debug_output("Received frame: ", internal.buffer, internal.len);
#endif /* #ifdef RAWNET_DEBUG_PKTDUMP */

        if (len & 1) {
            ++len;
        }

        *plen = len;

        /* we don't decide if this frame fits the needs;
         * by setting all zero, we let ethernet.c do the work
         * for us
         */
        *phashed = *phash_index = *pbroadcast = *pcorrect_mac = *pcrc_error = 0;

        /* this frame has been received correctly */
        *prx_ok = 1;

        return 1;
    }

    return 0;
}

char *rawnet_arch_get_standard_interface(void)
{
    char *dev, errbuf[PCAP_ERRBUF_SIZE];

    if (!EthernetPcapLoadLibrary()) {
        return NULL;
    }

    dev = (*p_pcap_lookupdev)(errbuf);

    return dev;
}
#endif /* #ifdef HAVE_PCAP */
