B0[0] &= 0x07;    B0[14] = B0[15] = 0;    aes_encrypt( &aes_ctx, B0, B );    XOR( h80211 + caplen - 8, B, 8 );    blocks = ( data_len + 16 - 1 ) / 16;    last = data_len % 16;    offset = z + 8;    for( i = 1; i <= blocks; i++ )    {        n = ( last > 0 && i == blocks ) ? last : 16;        B0[14] = ( i >> 8 ) & 0xFF;        B0[15] =   i & 0xFF;        aes_encrypt( &aes_ctx, B0, B );        XOR( h80211 + offset, B, n );        XOR( MIC, h80211 + offset, n );        aes_encrypt( &aes_ctx, MIC, MIC );        offset += n;    }    return( memcmp( h80211 + offset, MIC, 8 ) == 0 );}struct decap_stats{    unsigned long nb_read;      /* # of packets read       */    unsigned long nb_wep;       /* # of WEP data packets   */    unsigned long nb_wpa;       /* # of WPA data packets   */    unsigned long nb_plain;     /* # of plaintext packets  */    unsigned long nb_unwep;     /* # of decrypted WEP pkt  */    unsigned long nb_unwpa;     /* # of decrypted WPA pkt  */}stats;struct options{    int no_convert;    char essid[36];    char passphrase[65];    uchar bssid[6];    uchar pmk[40];    uchar wepkey[64];    int weplen, crypt;}opt;uchar buffer[65536];/* this routine handles to 802.11 to Ethernet translation */int write_packet( FILE *f_out, struct pcap_pkthdr *pkh, uchar *h80211 ){    int n;    uchar arphdr[12];    if( opt.no_convert )    {        if( buffer != h80211 )            memcpy( buffer, h80211, pkh->caplen );    }    else    {        /* create the Ethernet link layer (MAC dst+src) */        switch( h80211[1] & 3 )        {            case  0:    /* To DS = 0, From DS = 0: DA, SA, BSSID */                memcpy( arphdr + 0, h80211 +  4, 6 );                memcpy( arphdr + 6, h80211 + 10, 6 );                break;            case  1:    /* To DS = 1, From DS = 0: BSSID, SA, DA */                memcpy( arphdr + 0, h80211 + 16, 6 );                memcpy( arphdr + 6, h80211 + 10, 6 );                break;            case  2:    /* To DS = 0, From DS = 1: DA, BSSID, SA */                memcpy( arphdr + 0, h80211 +  4, 6 );                memcpy( arphdr + 6, h80211 + 16, 6 );                break;            default:    /* To DS = 1, From DS = 1: RA, TA, DA, SA */                memcpy( arphdr + 0, h80211 + 16, 6 );                memcpy( arphdr + 6, h80211 + 24, 6 );                break;        }        /* remove the 802.11 + LLC header */        if( ( h80211[1] & 3 ) != 3 )        {            pkh->len    -= 24 + 6;            pkh->caplen -= 24 + 6;            memcpy( buffer + 12, h80211 + 30, pkh->caplen );        }        else        {            pkh->len    -= 30 + 6;            pkh->caplen -= 30 + 6;            memcpy( buffer + 12, h80211 + 36, pkh->caplen );        }        memcpy( buffer, arphdr, 12 );        pkh->len    += 12;        pkh->caplen += 12;    }    n = sizeof( struct pcap_pkthdr );    if( fwrite( pkh, 1, n, f_out ) != (size_t) n )    {        perror( "fwrite(packet header) failed" );        return( 1 );    }    n = pkh->caplen;    if( fwrite( buffer, 1, n, f_out ) != (size_t) n )    {        perror( "fwrite(packet data) failed" );        return( 1 );    }    return( 0 );}int main( int argc, char *argv[] ){    time_t tt;    uint magic;    char *s, buf[128];    FILE *f_in, *f_out;    unsigned long crc;    int i = 0, n, z, linktype;    uchar ZERO[32], *h80211;    uchar bssid[6], stmac[6];    struct ST_info *st_1st;    struct ST_info *st_cur;    struct ST_info *st_prv;    struct pcap_file_header pfh;    struct pcap_pkthdr pkh;    /* parse the arguments */    memset( ZERO, 0, sizeof( ZERO ) );    memset( &opt, 0, sizeof( opt  ) );    while( 1 )    {        int option = getopt( argc, argv, "lb:k:e:p:w:" );        if( option < 0 ) break;        switch( option )        {            case 'l' :                opt.no_convert = 1;                break;            case 'b' :                i = 0;                s = optarg;                while( sscanf( s, "%x", &n ) == 1 )                {                    if( n < 0 || n > 255 )                    {                        printf( "Invalid BSSID (not a MAC).\n" );                        return( 1 );                    }                    opt.bssid[i] = n;                    if( ++i > 6 ) break;                    if( ! ( s = strchr( s, ':' ) ) )                        break;                    s++;                }                if( i != 6 )                {                    printf( "Invalid BSSID (not a MAC).\n" );                    return( 1 );                }                break;            case 'k' :                if( opt.crypt != CRYPT_NONE )                {                    printf( "Encryption key already specified.\n" );                    return( 1 );                }                opt.crypt = CRYPT_WPA;                i = 0;                s = optarg;                buf[0] = s[0];                buf[1] = s[1];                buf[2] = '\0';                while( sscanf( buf, "%x", &n ) == 1 )                {                    if( n < 0 || n > 255 )                    {                        printf( "Invalid WPA PMK.\n" );                        return( 1 );                    }                    opt.pmk[i++] = n;                    if( i >= 32 ) break;                    s += 2;                    if( s[0] == ':' || s[0] == '-' )                        s++;                    if( s[0] == '\0' || s[1] == '\0' )                        break;                    buf[0] = s[0];                    buf[1] = s[1];                }                if( i != 32 )                {                    printf( "Invalid WPA PMK.\n" );                    return( 1 );                }                break;            case 'e' :				if ( opt.essid[0])				{					printf( "ESSID already specified.\n" );                    return( 1 );				}                memset(  opt.essid, 0, sizeof( opt.essid ) );                strncpy( opt.essid, optarg, sizeof( opt.essid ) - 1 );                break;            case 'p' :                if( opt.crypt != CRYPT_NONE )                {                    printf( "Encryption key already specified.\n" );                    return( 1 );                }                opt.crypt = CRYPT_WPA;                memset(  opt.passphrase, 0, sizeof( opt.passphrase ) );                strncpy( opt.passphrase, optarg, sizeof( opt.passphrase ) - 1 );                break;            case 'w' :                if( opt.crypt != CRYPT_NONE )                {                    printf( "Encryption key already specified.\n" );                    return( 1 );                }                opt.crypt = CRYPT_WEP;                i = 0;                s = optarg;                buf[0] = s[0];                buf[1] = s[1];                buf[2] = '\0';                while( sscanf( buf, "%x", &n ) == 1 )                {                    if( n < 0 || n > 255 )                    {                        printf( "Invalid WEP key.\n" );                        return( 1 );                    }                    opt.wepkey[i++] = n;                    if( i >= 64 ) break;                    s += 2;                    if( s[0] == ':' || s[0] == '-' )                        s++;                    if( s[0] == '\0' || s[1] == '\0' )                        break;                    buf[0] = s[0];                    buf[1] = s[1];                }                if( i != 5 && i != 13 && i != 16 && i != 29 && i != 61 )                {                    printf( "Invalid WEP key length.\n" );                    return( 1 );                }                opt.weplen = i;                break;            default : goto usage;        }    }    if( argc - optind != 1 )    {    usage:        printf( usage, getVersion("Airdecap-ng", _MAJ, _MIN, _SUB_MIN, _BETA)  );        return( 1 );    }    if( opt.crypt == CRYPT_WPA )    {        if( opt.passphrase[0] != '\0' )        {            /* compute the Pairwise Master Key */            if( opt.essid[0] == '\0' )            {                printf( "You must also specify the ESSID (-e).\n" );                return( 1 );            }            calc_pmk( opt.passphrase, opt.essid, opt.pmk );        }    }    /* open the input and output pcap files */    if( ( f_in = fopen( argv[optind], "rb" ) ) == NULL )    {        perror( "fopen failed\n" );        printf( "Could not open \"%s\".\n", argv[optind] );        return( 1 );    }    n = sizeof( pfh );    if( fread( &pfh, 1, n, f_in ) != (size_t) n )    {        perror( "fread(pcap file header) failed" );        return( 1 );    }    if( pfh.magic != TCPDUMP_MAGIC &&        pfh.magic != TCPDUMP_CIGAM )    {        printf( "\"%s\" isn't a pcap file (expected "                "TCPDUMP_MAGIC).\n", argv[optind] );        return( 1 );    }    if( ( magic = pfh.magic ) == TCPDUMP_CIGAM )        SWAP32( pfh.linktype );    if( pfh.linktype != LINKTYPE_IEEE802_11 &&        pfh.linktype != LINKTYPE_PRISM_HEADER &&        pfh.linktype != LINKTYPE_RADIOTAP_HDR )    {        printf( "\"%s\" isn't a regular 802.11 "                "(wireless) capture.\n", argv[optind] );        return( 1 );    }    linktype = pfh.linktype;    n = strlen( argv[optind] );    if( n > 4 && ( n + 5 < (int) sizeof( buffer ) ) &&        argv[optind][n - 4] == '.' )    {        memcpy( buffer, argv[optind], n - 4 );