src/cdp.c

   1 /*
   2  * Mausezahn - A fast versatile traffic generator
   3  * Copyright (C) 2008 Herbert Haas
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License version 2 as published by the
   7  * Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
  12  * details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, see http://www.gnu.org/licenses/gpl-2.0.html
  16  *
  17 */
  18
  19 /////////////////////////////////////////////////////////////////////
  20 //
  21 //  Send CDP packets
  22 //
  23 /////////////////////////////////////////////////////////////////////
  24
  25
  26 #include "mz.h"
  27 #include "cli.h"
  28
  29
  30 #define MZ_CDP_HELP \
  31                 "| CDP type: Send arbitrary CDP packets.\n" \
  32                 "| Note:\n" \
  33                 "| - The Ethernet dst and src MAC addresses can be specified but can be also 'rand'.\n" \
  34                 "| - If dst and src are NOT specified then practical defaults are used (src=own MAC, dst=01:00:0C:CC:CC:CC).\n" \
  35                 "|\n" \
  36                 "|  ARGUMENT SYNTAX: -t cdp [arguments]\n" \
  37                 "|\n" \
  38                 "|  ARGUMENTS:\n" \
  39                 "|\n" \
  40                 "|    version ...... 0-255, default: 2\n" \
  41                 "|    ttl     ...... 0-255, default: 180 s\n" \
  42                 "|    sum     ...... 0000-ffff, default: automatically computed\n" \
  43                 "|\n" \
  44                 "|   TLVs:                  Description:                           Example:\n" \
  45                 "|\n" \
  46                 "|    tlv_id        ....... Device ID                              Mausezahn station\n" \
  47                 "|    tlv_address   ....... Sending interface address              10.1.1.2\n" \
  48                 "|    tlv_portid    ....... Port Identifier                        2/23\n" \
  49                 "|    tlv_cap       ....... Capabilities (hex<7f)                  2a\n" \
  50                 "|    tlv_version   ....... Software Version                       ver3.0\n" \
  51                 "|    tlv_platform  ....... Hardware Platform                      WS-C6509-E\n" \
  52                 "|    tlv_vtpdomain ....... VTP Management Domain                  MyVTPdomain\n" \
  53                 "|    tlv_native    ....... Native VLAN number (0-4095)            42\n" \
  54                 "|    tlv_duplex    ....... Full or half duplex                    full\n" \
  55                 "|    tlv_mgmt      ....... Management IP address                  192.168.1.2\n" \
  56                 "|\n" \
  57                 "|    tlv        .......... Create ANY TLV using the format: tlv=<type>/<value>, such as tlv=42/mausezahn\n" \
  58                 "|                    Note: Currently you must omit spaces within <value>! Use underscore instead.\n" \
  59                 "|    tlvhex     .......... Create ANY TLV and specify the value in hexformat, such as tlv=42/ca:fe:ba:be\n" \
  60                 "|    payload|p  .......... Optional additional TLVs or any other bytes specified in hex\n" \
  61                 "|\n" \
  62                 "|    When the tlv* arguments are used, the TLV length parameter is automatically set.\n" \
  63                 "|\n" \
  64                 "|    The capability flags from MSB to LSB are:\n" \
  65                 "|      0 - Repeater - IGMP - Host - Switch - SrcRouteBrdg - TranspBrdg - Router\n" \
  66                 "|\n" \
  67                 "|    Optionally the keyword 'change' will create a different System name TLV every time a CDP\n" \
  68                 "|    packet is sent. This can be used to fill up a CDP database with different test values.\n" \
  69                 "|    Additionally use the '-a rand' command to use different source MAC addresses.\n" \
  70                 "|\n" \
  71                 "| EXAMPLES:\n" \
  72                 "|\n" \
  73                 "|    Announce Device ID 'Espresso3000', Capabilities: Router, native VLAN 301:\n" \
  74                 "|    mz eth0 -t cdp \"tlv_id=Espresso3000, tlv_cap=01, tlv_native=301\"\n" \
  75                 "|\n" \
  76                 "|    Create another TLV using the payload interface (here voice VLAN 400):\n" \
  77                 "|    mz eth0 -t cdp p=00:0e:00:07:01:01:90\n"
  78
  79
  80
  81
  82
  83 u_int16_t checksum16 (u_int16_t len, u_int8_t buff[])
  84 {
  85
  86    u_int16_t word16;
  87    u_int32_t sum=0;
  88    u_int16_t i;
  89
  90    // make 16 bit words out of every two adjacent 8 bit words in the packet and add them up
  91    for (i=0; i<len; i=i+2)
  92      {
  93         word16 =((buff[i]<<8)&0xFF00)+(buff[i+1]&0xFF);
  94         sum = sum + (u_int32_t) word16;
  95      }
  96
  97    // take only 16 bits out of the 32 bit sum and add up the carries
  98    while (sum>>16)
  99      sum = (sum & 0xFFFF)+(sum >> 16);
 100
 101    // one's complement the result
 102    sum = ~sum;
 103
 104    return ((u_int16_t) sum);
 105 }
 106
 107
 108 // Creates a TLV and returns the whole length of the TLV
 109 unsigned int create_tlv (u_int16_t        type,       // The 16-bit TYPE number
 110                          u_int8_t        *value,      // The VALUE as prepared hex-array
 111                          unsigned int     value_len,  // needed because VALUE maybe not \0 terminated
 112                          u_int8_t        *target)     // the RESULT i. e. the complete TLV
 113 {
 114    unsigned int tlvlen;
 115    u_int8_t *x;
 116
 117    x = (u_int8_t*) &type;    // set TYPE
 118    target[0] = *(x+1);
 119    target[1] = *(x);
 120
 121    tlvlen = value_len + 4;   // set VALUE
 122    x = (u_int8_t*) &tlvlen;
 123    target[2] = *(x+1);
 124    target[3] = *(x);
 125
 126    target+=4;
 127    memcpy((void*) target, (void*) value, (size_t) value_len);
 128
 129    return tlvlen;
 130 }
 131
 132
 133
 134
 135 // NOTE: The Length field indicates the total length, in bytes, of the type, length, and value fields!
 136 //
 137 // Interesting TLVs:
 138 //
 139 // TYPE VALUE
 140 // 0001 Device-ID
 141 // 0002 IP Addresses
 142 // 0003 Port ID such as 2/22
 143 // 0004 Capabilities (Len=8, consists of flags only: Router, TBrdg, SRBrdgm, Switch, Host, IGMP, Repeater)
 144 // 0005 SW Version
 145 // 0006 Platform
 146 // 0009 VTP Domain
 147 // 000a Native VLAN, e.g. 00:0a 00:06 01:2d identifies native VLAN number 301 (=01:2d)
 148 // 000b Duplex
 149 // 000e VoIP VLAN, e.g. 00:0e 00:07 01 01:90 identifies DATA (=01) and VLAN 400 (=01:90)
 150 // 0012 Trust Bitmap
 151 // 0013 Untrusted Port CoS
 152 // 0014 System Name (!!!)
 153 // 0015 System Object Identifier
 154 // 0016 Management Address (!!!), e.g. 0016 0011(=len 17) 00-00-00-01(=one IP only) 01-01-cc-00-04-90-fe-f8-10(=144.254.248.16)
 155 // 0017 Location
 156 // 001a Unknown (???)
 157 //
 158 // The IP address format is a bit strange as 0016 for example demonstrates...
 159
 160
 161
 162 int send_cdp ()
 163 {
 164    libnet_t             *l;
 165    libnet_ptag_t         t;
 166    char
 167      errbuf[LIBNET_ERRBUF_SIZE],
 168      argval[1024];
 169
 170    u_int8_t
 171      packet[MAX_PAYLOAD_SIZE], // this one will finally contain the whole cdp packet (without LLC/SNAP!)
 172      *x,
 173      value[1024],   // USE THIS FOR ANYTHING YOU LIKE !!!
 174      value1[1024],  // This one is reserved for some code - Don't use it again!
 175      value2[1024],  // This one is reserved for some code - Don't use it again!
 176      tlv[1024],
 177      default_id[15] = "Mausezahn rules",
 178      llcsnap[8]=
 179      {
 180         0xaa, 0xaa, 0x03, 0x00, 0x00, 0x0c, 0x20, 0x00
 181      };
 182
 183    unsigned int
 184      len=0,
 185      len1=0,
 186      len2=0,
 187      type1,
 188      type2;
 189
 190    u_int16_t
 191      dummy16=0,
 192      tlv_len=0;
 193
 194    u_int32_t
 195      next_pbyte=0, // points to the next free byte in tx.cdp_payload
 196      dummy32=0,
 197      packet_s;
 198
 199    char
 200      pld[2048];
 201
 202
 203    unsigned int i=0, count, delay;
 204    int
 205      eth_src_rand=0,
 206      change_value=0;
 207    long int j=0;
 208
 209
 210    if (tx.dot1Q)
 211      {
 212         fprintf(stderr," Note: CDP mode does not support 802.1Q builder.\n");
 213         exit(1);
 214      }
 215
 216    if (tx.mpls)
 217      {
 218         fprintf(stderr," Note: CDP mode does not support MPLS builder.\n");
 219         exit(1);
 220      }
 221
 222
 223    if (getarg(tx.arg_string,"help", NULL)==1)
 224      {
 225         if (mz_port)
 226           {
 227              cli_print(gcli, "%s", MZ_CDP_HELP);
 228              return -1;
 229           }
 230         else
 231           {
 232              fprintf(stderr,"\n"
 233                      MAUSEZAHN_VERSION
 234                      "\n%s", MZ_CDP_HELP);
 235              exit(0);
 236           }
 237
 238      }
 239
 240    ///////////////////////////////////////////////////////////////////////
 241    // initial defaults:
 242    if (tx.cdp_ttl==0) tx.cdp_ttl=0xb4; // 180 seconds
 243
 244    if (tx.cdp_version==0) tx.cdp_version = 0x02;
 245
 246    // The ID is the only required TLV
 247    // If another function already specified it then it must also set the lenght:
 248    if (tx.cdp_tlv_id_len==0) // not set
 249      {
 250         memcpy((void*) tx.cdp_tlv_id, (void*) default_id, 15);
 251         tx.cdp_tlv_id_len=15;
 252      }
 253
 254
 255
 256
 257    ///////////////////////////////////////////////////////////////////////
 258    //
 259    // Now check for user arguments:
 260
 261
 262    if ( (getarg(tx.arg_string,"version", argval)==1) || (getarg(tx.arg_string,"ver", argval)==1) )
 263      {
 264         if (str2int(argval)>255)
 265           {
 266              fprintf(stderr," mz/send_cdp: version range exceeded, adjusted to max value.\n");
 267              tx.cdp_version = 0xff;
 268           }
 269         else
 270           {
 271              tx.cdp_version = (u_int8_t) str2int(argval);
 272           }
 273      }
 274
 275
 276    if (getarg(tx.arg_string,"ttl", argval)==1)
 277      {
 278         if (str2int(argval)>255)
 279           {
 280              fprintf(stderr," mz/send_cdp: TTL range exceeded, adjusted to max value.\n");
 281              tx.cdp_ttl = 0xff;
 282           }
 283         else
 284           {
 285              tx.cdp_ttl = (u_int8_t) str2int(argval);
 286           }
 287      }
 288
 289    if (getarg(tx.arg_string,"sum", argval)==1)
 290      {
 291
 292         if (strtol(argval,NULL,16)>65535)
 293           {
 294              fprintf(stderr," mz/send_cdp: checksum range exceeded, adjusted to max value.\n");
 295              tx.cdp_sum = 0xffff;
 296           }
 297         else
 298           {
 299              tx.cdp_sum = (u_int16_t) strtol(argval,NULL,16);
 300           }
 301      }
 302
 303    ////////
 304    //
 305    // Provide a basic interface for the most important TLVs:
 306    //
 307
 308    if (getarg(tx.arg_string,"tlv_id", argval)==1)
 309      {
 310         // simply overwrite current content in tx.cdp_tlv_id
 311         tx.cdp_tlv_id[0] = '\0';
 312         strncpy((char*) tx.cdp_tlv_id, argval,2048);
 313         tx.cdp_tlv_id_len = strlen ((char*)tx.cdp_tlv_id);
 314      }
 315
 316
 317    //
 318    // This is something ugly ;-)
 319    //
 320
 321    if (getarg(tx.arg_string,"change", NULL)==1)
 322      {
 323         memcpy((void*) tx.cdp_tlv_id, (void*) "Mausezahn 00000000000", 21);
 324         tx.cdp_tlv_id_len=21;
 325         change_value = 1;
 326      }
 327
 328
 329    //
 330    // NOW write the ID-TLV;  this is the only REQUIRED TLV !!!
 331    // and this TLV should be the FIRST one - that's why we
 332    // write it immediately here now:
 333    //
 334    tlv_len = create_tlv (1, tx.cdp_tlv_id, tx.cdp_tlv_id_len, tlv);
 335    memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 336    next_pbyte += tlv_len;
 337
 338    //
 339    // Now the other TLVs may follow:
 340    //
 341
 342    //  Format: Type=2, Len=17, NrOfAddr=00:00:00:01, Protocol=01:01:cc:00, AddrLen=4, IP_Address
 343    // Example: tlv_address = 192.168.1.10
 344    //    Note: currently only one address supported
 345    if (getarg(tx.arg_string,"tlv_address", argval)==1)
 346      {
 347         dummy32 = str2ip32 (argval);
 348         x = (u_int8_t*) &dummy32;
 349         value[0] = 0x00; // NrOfAddr
 350         value[1] = 0x00;
 351         value[2] = 0x00;
 352         value[3] = 0x01;
 353
 354         value[4] = 0x01; // Protocol
 355         value[5] = 0x01;
 356         value[6] = 0xcc;
 357         value[7] = 0x00;
 358
 359         value[8] = 0x04; // AddrLen
 360
 361         value[9] = *(x+3);
 362         value[10] = *(x+2);
 363         value[11] = *(x+1);
 364         value[12] = *(x);
 365
 366         tlv_len = create_tlv (2, value, 13, tlv);
 367         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 368         next_pbyte += tlv_len;
 369      }
 370
 371
 372
 373    //  Format: Type=3
 374    // Example: tlv_portid = 2/23
 375    //    Note:
 376    if (getarg(tx.arg_string,"tlv_portid", argval)==1)
 377      {
 378         tlv_len = create_tlv (3, (u_int8_t*) argval, strlen(argval), tlv);
 379         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 380         next_pbyte += tlv_len;
 381      }
 382
 383    //  Format: Type=4
 384    // Example: "tlv_cap = 2a"    (= 0010 1010)
 385    //   Flags: MSB=0 - Repeater - IGMP - Host - Switch - SrcRouteBrdg - TranspBrdg - Router(LSB)
 386    if (getarg(tx.arg_string,"tlv_cap", argval)==1)
 387      {
 388         if (strlen(argval)>2)
 389           {
 390              fprintf(stderr," mz/send_cdp: Capability value must be specified as a two-digit hexadecimal value!\n");
 391              exit(1);
 392           }
 393         else
 394           {
 395              str2hex(argval, value+3, 1020);
 396              if (value[3]>0x7f)
 397                {
 398                   fprintf(stderr," mz/send_cdp: Capability value must not exceed 7F(hex)\n");
 399                   exit(1);
 400                }
 401           }
 402
 403         value[0]=0x00;
 404         value[1]=0x00;
 405         value[2]=0x00;
 406         tlv_len = create_tlv (4, value, 4, tlv);
 407         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 408         next_pbyte += tlv_len;
 409      }
 410
 411
 412    //  Format: Type=5
 413    // Example: tlv_version = Mausezahn_version_xyz
 414    //    Note: Avoid spaces, use underscore instead
 415    if (getarg(tx.arg_string,"tlv_version", argval)==1)
 416      {
 417         tlv_len = create_tlv (5, (u_int8_t*) argval, strlen(argval), tlv);
 418         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 419         next_pbyte += tlv_len;
 420      }
 421
 422
 423    //  Format: Type=6
 424    // Example: tlv_platform = WS-C6509-E
 425    //    Note:
 426    if (getarg(tx.arg_string,"tlv_platform", argval)==1)
 427      {
 428         tlv_len = create_tlv (6, (u_int8_t*) argval, strlen(argval), tlv);
 429         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 430         next_pbyte += tlv_len;
 431      }
 432
 433    //  Format: Type=9
 434    // Example: tlv_vtpdomain = MyVTPdomain
 435    //    Note:
 436    if (getarg(tx.arg_string,"tlv_vtpdomain", argval)==1)
 437      {
 438         tlv_len = create_tlv (9, (u_int8_t*) argval, strlen(argval), tlv);
 439         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 440         next_pbyte += tlv_len;
 441      }
 442
 443
 444    //  Format: Type=10, Len=17
 445    // Example: tlv_native = 100
 446    //    Note:
 447    if (getarg(tx.arg_string,"tlv_native", argval)==1)
 448      {
 449         dummy16 = (u_int16_t) str2int(argval);
 450         if (dummy16>4095)
 451           {
 452              fprintf(stderr," mz/WARNING: native VLAN value exceeds max value (4095) - hope you know what you do!\n");
 453           }
 454
 455         x = (u_int8_t*) &dummy16;
 456         value[0] = *(x+1);
 457         value[1] = *(x);
 458         tlv_len = create_tlv (10, value, 2, tlv);
 459         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 460         next_pbyte += tlv_len;
 461      }
 462
 463    //  Format: Type=11
 464    // Example: tlv_duplex = full | half
 465    //    Note:
 466    if (getarg(tx.arg_string,"tlv_duplex", argval)==1)
 467      {
 468         if (strncmp(argval,"full",10)==0)
 469           {
 470              value[0]=0x01;
 471           }
 472         else if (strncmp(argval,"half",10)==0)
 473           {
 474              value[0]=0x00;
 475           }
 476         else
 477           {
 478              value[0]=(u_int8_t) str2int(argval);
 479              if (!quiet)
 480                {
 481                   fprintf(stderr," mz/Warning: Only keywords 'half' or 'full' supported."
 482                                  " Will interprete input as integer.\n");
 483                }
 484
 485           }
 486
 487         tlv_len = create_tlv (11, value, 1, tlv);
 488         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 489         next_pbyte += tlv_len;
 490      }
 491
 492    //  Format: Type=22, Len=17, NrOfAddr=00:00:00:01, Protocol=01:01:cc:00, AddrLen=4, IP_Address
 493    // Example: tlv_mgmt = 10.1.1.99
 494    //    Note: Same format as tlv_address
 495    if (getarg(tx.arg_string,"tlv_mgmt", argval)==1)
 496      {
 497         dummy32 = str2ip32 (argval);
 498         x = (u_int8_t*) &dummy32;
 499         value[0] = 0x00; // NrOfAddr
 500         value[1] = 0x00;
 501         value[2] = 0x00;
 502         value[3] = 0x01;
 503
 504         value[4] = 0x01; // Protocol
 505         value[5] = 0x01;
 506         value[6] = 0xcc;
 507         value[7] = 0x00;
 508
 509         value[8] = 0x04; // AddrLen
 510
 511         value[9] = *(x+3);
 512         value[10] = *(x+2);
 513         value[11] = *(x+1);
 514         value[12] = *(x);
 515
 516         tlv_len = create_tlv (22, value, 13, tlv);
 517         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 518         next_pbyte += tlv_len;
 519
 520      }
 521
 522
 523
 524    //
 525    // Eventually there are two generic TLV interfaces: tlv and tlvhex
 526    //
 527
 528    if (getarg(tx.arg_string,"tlv", argval)==1)
 529      {
 530         // split in TYPE and VALUE
 531         sscanf(argval, "%u/%s",  &type1, value1);
 532         len1 = strlen((const char*) value1);
 533
 534      }
 535
 536    if (getarg(tx.arg_string,"tlvhex", argval)==1)
 537      {
 538         // split in TYPE and VALUE
 539         sscanf(argval, "%u/%s",  &type2, pld);
 540         len2 = str2hex(pld, value2, 1023);
 541      }
 542
 543
 544    //
 545    // Finally the optional payload interface allows to specify subsequent TLVs or any other bytes:
 546    //
 547    if ( (getarg(tx.arg_string,"payload", argval)==1) || (getarg(tx.arg_string,"p", argval)==1))
 548      {
 549         len = str2hex (argval, value, 1023);
 550         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) value, len);
 551         next_pbyte += len;
 552      }
 553
 554
 555
 556    ///////////////////////////////////////////////////////////////
 557
 558
 559
 560    // Write other TLVs: First the ASCII specified:
 561    if (len1)
 562      {
 563         tlv_len = create_tlv (type1, value1, len1 , tlv);
 564         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 565         next_pbyte += tlv_len;
 566      }
 567
 568    // Write other TLVs: Then the HEX specified:
 569    if (len2)
 570      {
 571         tlv_len = create_tlv (type2, value2, len2 , tlv);
 572         memcpy((void*) tx.cdp_payload+next_pbyte, (void*) tlv, tlv_len);
 573         next_pbyte += tlv_len;
 574      }
 575
 576
 577    tx.cdp_payload_s = next_pbyte;
 578
 579    // CHECK:
 580    //   bs2str(tx.cdp_payload, pld, tx.cdp_payload_s);
 581    //   printf("PAYLOAD= %s\n",pld);
 582
 583
 584 ////////////////////////////
 585 //
 586
 587    // Open the link - for the intermediate CDP/LLC frame
 588    l = libnet_init(LIBNET_LINK_ADV, tx.device, errbuf);
 589
 590    if (l == NULL)
 591      {
 592         fprintf(stderr, "%s", errbuf);
 593         exit(EXIT_FAILURE);
 594      }
 595
 596    if (check_eth_mac_txt(ETH_DST))  // if '1' then user did not set MAC address (or problem occurred)
 597      {
 598         str2hex("01:00:0C:CC:CC:CC", tx.eth_dst, 6);
 599      }
 600
 601    if (check_eth_mac_txt(ETH_SRC))  // if '1' then user did not set MAC address (or problem occurred)
 602      {
 603         // own mac per default (see init.c)
 604      }
 605
 606    count = tx.count;
 607    eth_src_rand = tx.eth_src_rand;
 608    delay = tx.delay;
 609
 610    // ---------------------------------------------------
 611    // If you want to change CDP fields during a LOOP then
 612    // START the loop from HERE:
 613    //
 614
 615    ////////////////////////////////////
 616    // Now create the whole CDP packet:
 617
 618    packet[0] = tx.cdp_version;            // VERSION
 619    packet[1] = tx.cdp_ttl;                // TTL
 620    packet[2] = 0x00;                      // CHECKSUM
 621    packet[3] = 0x00;
 622
 623    // Now add the TLVs
 624    memcpy ((void*) packet+4, (void*) tx.cdp_payload, tx.cdp_payload_s);
 625    packet_s = tx.cdp_payload_s + 4;
 626
 627    // Check whether packet is an even length (i.e. is a multiple of 16 bits = 2 bytes);
 628    if (packet_s%2>0)
 629      {
 630         packet[packet_s++]=0x00;
 631         packet[packet_s++]=0x17;
 632         packet[packet_s++]=0x00;
 633         packet[packet_s++]=0x05;
 634         packet[packet_s++]=0x00;
 635      }
 636
 637
 638    // Now update the checksum:
 639    if (tx.cdp_sum == 0) // Otherwise user specified the checksum (usually a wrong one ;-))
 640      {
 641         tx.cdp_sum = checksum16(packet_s, packet);
 642      }
 643    x = (u_int8_t *) &tx.cdp_sum;
 644    packet[2] = *(x+1);
 645    packet[3] = *(x);
 646
 647    // CHECK the CDP packet
 648    //bs2str(packet, pld, packet_s);
 649    //printf("CDP= %s\n",pld);
 650
 651
 652 //   printf("Len = %u Checksum = %04x \n", packet_s-8, tx.cdp_sum);
 653
 654
 655    ///////////////////////////////////////////////////////////////
 656    // Now create the whole tx.eth_payload = LLC/SNAP + CDP packet
 657    // First the LLC/SNAP header:
 658    memcpy ((void*) tx.eth_payload, (void*) llcsnap, 8);
 659    memcpy ((void*) tx.eth_payload+8, (void*) packet, packet_s);
 660    tx.eth_payload_s = packet_s +8;
 661
 662
 663    // CHECK the whole 802.3 payload
 664    // bs2str(tx.eth_payload, pld, tx.eth_payload_s);
 665    // printf("PACKET = %s\n",pld);
 666
 667
 668    t = libnet_build_802_3 (tx.eth_dst,
 669                            tx.eth_src,
 670                            tx.eth_payload_s,
 671                            tx.eth_payload,
 672                            tx.eth_payload_s,
 673                            l,
 674                            0);
 675
 676
 677
 678    // this is for the statistics:
 679    mz_start = clock();
 680    total_d = tx.count;
 681
 682    if (!count) goto AGAIN;
 683
 684    for (i=0; i<count; i++)
 685      {
 686         AGAIN:
 687
 688         if (eth_src_rand)
 689           {
 690              tx.eth_src[0] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256) & 0xFE; // keeps bcast-bit zero
 691              tx.eth_src[1] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256);
 692              tx.eth_src[2] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256);
 693              tx.eth_src[3] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256);
 694              tx.eth_src[4] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256);
 695              tx.eth_src[5] = (u_int8_t) ( ((float) rand()/RAND_MAX)*256);
 696
 697              t = libnet_build_802_3 (tx.eth_dst,
 698                                      tx.eth_src,
 699                                      tx.eth_payload_s,
 700                                      tx.eth_payload,
 701                                      tx.eth_payload_s,
 702                                      l,
 703                                      t);
 704
 705           }
 706
 707
 708         libnet_write(l);
 709
 710         if (verbose)
 711           {
 712              bs2str(tx.eth_payload+8, pld, tx.eth_payload_s-8);
 713              fprintf(stderr," Sent CDP: (Ver=%u, TTL=%u) %s\n", tx.cdp_version, tx.cdp_ttl, pld);
 714           }
 715
 716         if (delay) SLEEP (delay);
 717
 718         if (change_value)
 719           {
 720              // Note: this only works when default_id has been used
 721              //       because otherwise the TLV with the ID might be too short!!!
 722
 723              // Offset 26-36 contains 00000000000 (of the default id)
 724              // ASCII 0x30-0x39 contain numbers 0-9
 725
 726              tx.eth_payload[26] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 727              tx.eth_payload[27] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 728              tx.eth_payload[28] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 729              tx.eth_payload[29] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 730              tx.eth_payload[30] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 731              tx.eth_payload[31] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 732              tx.eth_payload[32] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 733              tx.eth_payload[33] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 734              tx.eth_payload[34] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 735              tx.eth_payload[35] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 736              tx.eth_payload[36] = (u_int8_t) (0x30+ ((float) rand()/RAND_MAX)*10);
 737
 738              tx.eth_payload[10] = 0x00;  // reset the checksum
 739              tx.eth_payload[11] = 0x00;
 740              tx.cdp_sum = checksum16(tx.eth_payload_s-8, tx.eth_payload+8);
 741              x = (u_int8_t *) &tx.cdp_sum;
 742              tx.eth_payload[10] = *(x+1);
 743              tx.eth_payload[11] = *(x);
 744
 745              t = libnet_build_802_3 (tx.eth_dst,
 746                                      tx.eth_src,
 747                                      tx.eth_payload_s,
 748                                      tx.eth_payload,
 749                                      tx.eth_payload_s,
 750                                      l,
 751                                      t);
 752
 753              j++;
 754
 755           }
 756
 757         if (!count) goto AGAIN;
 758      }
 759
 760
 761    // Destroy contexts
 762    libnet_destroy(l);
 763
 764
 765
 766    return t;
 767
 768
 769 }