src/mops_ip.c

   1 /*
   2  * Mausezahn - A fast versatile traffic generator
   3  * Copyright (C) 2008-2010 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 #include "mz.h"
  21 #include "mops.h"
  22 #include "cli.h"
  23
  24
  25 // PURPOSE
  26 //
  27 //   Determine destination MAC address to provide direct or indirect
  28 //   delivery of IP packets, depending on which is appropriate.
  29 //
  30 //   Doing this, the caller must provide
  31 //     1) A pointer to the interface (within the device_list)
  32 //     2) The destination IP address
  33 //     3) A pointer to the destination MAC address
  34 //
  35 //   If a Class D (multicast) address is given, a proper IEEE multicast MAC
  36 //   address is derived.
  37 //
  38 // EXAMPLE
  39 //
  40 //    u_int8_t ip[4],
  41 //             mac[6];
  42 //
  43 //    mops_hton4 (mp->ip_src, ip);
  44 //
  45 //    mops_ip_get_dst_mac(&device_list[0], ip, mac);
  46 //
  47 // RETURN VALUES
  48 //
  49 //    0 upon success
  50 //    1 upon error
  51 //
  52 int mops_ip_get_dst_mac(struct device_struct *dev, u_int8_t *ip, u_int8_t *mac)
  53 {
  54         int i;
  55         u_int8_t dst_net[4];
  56
  57         if ((dev==NULL)||(ip==NULL)||(mac==NULL)) return 1;
  58
  59         // Multicast address?
  60         if ((0xe0 & ip[0]) == 0xe0) {
  61                 mac[0] = 0x01;
  62                 mac[1] = 0x00;
  63                 mac[2] = 0x5e;
  64                 mac[3] = ip[1] & 127;
  65                 mac[4] = ip[2];
  66                 mac[5] = ip[3];
  67                 return 0;
  68         }
  69
  70         // Is destination network == local network?
  71         for (i=0; i<4; i++) {
  72                 dst_net[i] = ip[i] & (u_int8_t) dev->mask[i];
  73         }
  74
  75         if (compare_ip(dst_net, dev->net)==0) {
  76                 // dst is on local LAN => resolve MAC!
  77                 service_arp(dev->dev, ip, mac);
  78         } else { // dst is on a remote network => use default gw!
  79                 for (i=0; i<6; i++) mac[i] = dev->mac_gw[i];
  80         }
  81
  82         return 0;
  83 }
  84
  85
  86 ///////////////////////////////////////////////////////////////////////////////////
  87 //
  88 // PURPOSE
  89 //
  90 //   Accept a DSCP specification as string argument
  91 //   and configure the IP-ToS field accordingly.
  92 //
  93 // EXAMPLE STRINGS
  94 //
  95 //   AF32        .... specify AF codepoint with class 3 and drop probability 2
  96 //   EF          .... specify Expedited Forwarding
  97 //   CS7         .... specify Code Selector 7
  98 //   101110      .... specify the DSCP in binary
  99 //   56          .... specify the DSCP in decimal
 100 //
 101 // RETURN VALUES
 102 //
 103 //  -1   general bad argument format
 104 //   0   upon success
 105 //   1   Invalid AF format (Format: AFxy, e. g. af31 or AF23)
 106 //   2   Invalid CS format
 107 //   3   Invalid decimal DSCP value
 108 //
 109 int mops_ip_dscp (struct mops* mp, char *argv)
 110 {
 111    int i;
 112    char cs[4], ps[4], str[16];
 113    u_int8_t c=0, p=0, dscp=0;
 114
 115    if (strlen(argv)==0) return -1;
 116    strncpy(str,argv,15);
 117
 118    if (strncasecmp(str, "af", 2)==0)    // e.g. 'AF32' or 'af41'
 119      {
 120         if (strlen(str)!=4)  return 1; // ERROR: Invalid AF codepoint
 121         i=sscanf(str, "%*[afAF]%c%c", cs, ps);
 122         cs[1]=0x00; ps[1]=0x00;
 123         c=(u_int8_t) str2int(cs);
 124         p=(u_int8_t) str2int(ps);
 125         if ((c<1)||(c>4)||(p<1)||(p>3)) return 1;
 126         // Now create correct ToS-byte representation: This is simple, since if a=3 and b=1
 127         // we have in binary already a=0000 0011 and b=0000 0001 and with bit-shifting we
 128         // get the desired dscp=011 01 000 (the least signfificant three bits are always 0).
 129         c <<=5;
 130         p <<=3;
 131         dscp = c | p;
 132      }
 133    else if (strncasecmp(str, "cs", 2)==0)    // e.g. 'CS7' or 'cs4'
 134      {
 135         if (strlen(str)!=2)  return 2; // ERROR: Invalid Code Selector
 136         i=sscanf(str, "%*[afAF]%c", cs);
 137         cs[1]=0x00;
 138         c=(u_int8_t) str2int(cs);
 139         if (c>7) return 2;
 140         c <<=5;
 141         dscp = c;
 142      }
 143    else if (mz_strcmp(str, "ef", 2)==0) // e.g. 'ef' or 'EF'
 144      {
 145         dscp = 0xb8;  // = DSCP 46 = 101110 00 or 1011 1000
 146      }
 147    else if (mz_strisbinary(str)==6)  // binary, e. g. 101110
 148      {
 149         for (i=0; i<6; i++) if (str[i]=='1') dscp |= ( 0x01 << (5-i) );
 150         dscp <<= 2;
 151      }
 152    else if (strlen(str)==2) // decimal DSCP value
 153      {
 154         if ( !(isdigit(str[0])) || !(isdigit(str[1]))) return 3;
 155         dscp = (u_int8_t) str2int(str);
 156         if (dscp>63) return 3;
 157         dscp <<= 2;
 158      }
 159    else return -1;
 160
 161    // TEST: printf("dscp=%02x\n",dscp);
 162    mp->ip_tos = dscp;
 163
 164    return 0;
 165 }
 166
 167
 168
 169
 170
 171
 172
 173
 174 //
 175 // IP TOS-FIELD FORMAT
 176 //
 177 //      MSB                                       LSB
 178 //       0     1     2     3     4     5     6     7
 179 //    +-----+-----+-----+-----+-----+-----+-----+-----+   Note that the bit numbering is usually from right
 180 //    |                 | Del   Trp   Rel   Cst |     |   to left, but here is the original pic of the RFC
 181 //    |   PRECEDENCE    |          TOS          | MBZ |   1349. Also here, the MSB is left (strangely bit 0)
 182 //    |                 |                       |     |   and the LSB is right (strangely bit 7).
 183 //    +-----+-----+-----+-----+-----+-----+-----+-----+
 184 //
 185 // ARGUMENTS
 186 //                                               if unused
 187 //   ipp  ... IP Precedence (0..7)                  or -1
 188 //   tos  ... Type of Service (0..15)               or -1
 189 //   mbz  ... if 1 sets MBZ                         or 0
 190 int mops_ip_tos (struct mops* mp, int ipp, int tos, int mbz)
 191 {
 192    u_int8_t TOS=0;
 193
 194    if (ipp!=-1)
 195      {
 196         if (ipp>7) return 1; // Invalid IPP value
 197         TOS |= (ipp << 5);
 198      }
 199
 200    if (tos!=-1)
 201      {
 202         if (tos>15) return 2; // Invalid ToS value
 203         TOS |= (tos << 1);
 204      }
 205
 206    if (mbz==1) // not used if mbz is either 0 or -1
 207      {
 208         TOS |= 0x01; // set
 209      }
 210
 211    mp->ip_tos = TOS;
 212
 213    return 0;
 214 }
 215
 216
 217
 218 //
 219 //
 220 // =================== ONLY IP OPTION HANDLING FUNCTION BELOW ================
 221 //
 222 ///////////////////////////////////////////////////////////////////////////////
 223
 224
 225
 226 ///////////////////////////////////////////////////////////////////////////////
 227 //
 228 // There are two cases for the format of an option:
 229 //
 230 //   Case 1:  A single octet of option-type.
 231 //   Case 2:  An option-type octet, an option-length octet, and the
 232 //            actual option-data octets.
 233 //
 234 //  The option-length octet counts the WHOLE number of bytes of the option
 235 //
 236 //  The option-type consists of:
 237 //
 238 //  +--------+--------+--------+--------+--------+--------+--------+--------+
 239 //  | copied |  option class   |         number (identifies option)         |
 240 //  |  flag  |                 |                                            |
 241 //  +--------+-----------------+--------------------------------------------+
 242 //
 243 //
 244 // The following Internet options are defined in RFC 791:
 245 //
 246 //        CLASS NUMBER LENGTH DESCRIPTION
 247 //        ----- ------ ------ -----------
 248 //          0     0      -    End of Option list.  This option occupies only
 249 //                            1 octet; it has no length octet.
 250 //          0     1      -    No Operation.  This option occupies only 1
 251 //                            octet; it has no length octet.
 252 //          0     2     11    Security.  Used to carry Security,
 253 //                            Compartmentation, User Group (TCC), and
 254 //                            Handling Restriction Codes compatible with DOD
 255 //                            requirements.
 256 //          0     3     var.  Loose Source Routing.  Used to route the
 257 //                            internet datagram based on information
 258 //                            supplied by the source.
 259 //          0     9     var.  Strict Source Routing.  Used to route the
 260 //                            internet datagram based on information
 261 //                            supplied by the source.
 262 //          0     7     var.  Record Route.  Used to trace the route an
 263 //                            internet datagram takes.
 264 //          0     8      4    Stream ID.  Used to carry the stream
 265 //                            identifier.
 266 //          2     4     var.  Internet Timestamp.
 267 //
 268 //
 269 // Possible options and associated number in mp->ip_option_used
 270 //
 271 //   1 - Security and handling restrictions (for military applications)
 272 //   2 - Record route
 273 //   4 - Timestamp
 274 //   8 - Loose source routing
 275 //  16 - Strict source routing
 276 //
 277 //
 278
 279 // *** See RFCs 791, 1071, 1108 ***
 280
 281 // Remove all options
 282 int mops_ip_option_remove_all (struct mops* mp)
 283 {
 284         mp->ip_option_used = 0;
 285         mp->ip_option_s = 0;
 286    return 0;
 287 }
 288
 289
 290 // Add no-option
 291 int mops_ip_option_nop (struct mops* mp)
 292 {
 293
 294    return 0;
 295 }
 296
 297 // Add end of option list
 298 int mops_ip_option_eol (struct mops* mp)
 299 {
 300
 301    return 0;
 302 }
 303
 304
 305
 306 // Add loose source route option
 307 int mops_ip_option_lsr (struct mops* mp)
 308 {
 309
 310    return 0;
 311 }
 312
 313 // Add strict source route option
 314 int mops_ip_option_ssr (struct mops* mp)
 315 {
 316
 317    return 0;
 318 }
 319
 320 // Add record route option
 321 int mops_ip_option_rr (struct mops* mp)
 322 {
 323
 324    return 0;
 325 }
 326
 327 // Add time stamp option
 328 int mops_ip_option_ts (struct mops* mp)
 329 {
 330
 331    return 0;
 332 }
 333
 334
 335
 336 // Add security option.
 337 //
 338 // This option provides a way for hosts to send security, compartmentation,
 339 // handling restrictions, and TCC (closed user group) parameters.  The format
 340 // for this option is as follows:
 341 //
 342 //          +--------+--------+---//---+---//---+---//---+---//---+
 343 //          |10000010|00001011|SSS  SSS|CCC  CCC|HHH  HHH|  TCC   |
 344 //          +--------+--------+---//---+---//---+---//---+---//---+
 345 //           Type=130 Length=11
 346 //
 347 //        Security (S field):  16 bits
 348 //
 349 //          Specifies one of 16 levels of security (eight of which are
 350 //          reserved for future use).
 351 //
 352 //            00000000 00000000 - Unclassified
 353 //            11110001 00110101 - Confidential
 354 //            01111000 10011010 - EFTO
 355 //            10111100 01001101 - MMMM
 356 //            01011110 00100110 - PROG
 357 //            10101111 00010011 - Restricted
 358 //            11010111 10001000 - Secret
 359 //            01101011 11000101 - Top Secret
 360 //            00110101 11100010 - (Reserved for future use)
 361 //            10011010 11110001 - (Reserved for future use)
 362 //            01001101 01111000 - (Reserved for future use)
 363 //            00100100 10111101 - (Reserved for future use)
 364 //            00010011 01011110 - (Reserved for future use)
 365 //            10001001 10101111 - (Reserved for future use)
 366 //            11000100 11010110 - (Reserved for future use)
 367 //            11100010 01101011 - (Reserved for future use)
 368 //
 369 //
 370 //        Compartments (C field):  16 bits
 371 //
 372 //          An all zero value is used when the information transmitted is not
 373 //          compartmented.  Other values for the compartments field may be obtained
 374 //          from the Defense Intelligence Agency.
 375 //
 376 //        Handling Restrictions (H field):  16 bits
 377 //
 378 //          The values for the control and release markings are alphanumeric digraphs
 379 //          and are defined in the Defense Intelligence Agency Manual DIAM 65-19,
 380 //          "Standard Security Markings".
 381 //
 382 //        Transmission Control Code (TCC field):  24 bits
 383 //
 384 //          Provides a means to segregate traffic and define controlled communities
 385 //          of interest among subscribers. The TCC values are trigraphs, and are available
 386 //          from HQ DCA Code 530.
 387 //
 388 //        Must be copied on fragmentation.  This option appears at most
 389 //        once in a datagram.
 390
 391 int mops_ip_option_sec (struct mops* mp)
 392 {
 393
 394    return 0;
 395 }
 396
 397
 398 // Add the IP Router Alert Option - a method to efficiently signal
 399 // transit routers to more closely examine the contents of an IP packet.
 400 // See RFC 2113, and FYI also 3175 (RSVP Aggregation), and RFC 5350
 401 // (new IANA-defined Router Alert Options (RAO)).
 402 //
 403 // The Router Alert option has the following format:
 404 //
 405 //     +--------+--------+--------+--------+
 406 //     |10010100|00000100|  2 octet value  |
 407 //     +--------+--------+--------+--------+
 408 //
 409 // Type:
 410 //   Copied flag:  1 (all fragments must carry the option)
 411 //   Option class: 0 (control)
 412 //   Option number: 20 (decimal)
 413 //
 414 // Length: 4
 415 //
 416 // Value:  A two octet code with the following values:
 417 //   0 - Router shall examine packet
 418 //   1-65535 - Reserved
 419 //
 420 // RETURN VALUE: 0 upon success
 421 //               1 upon failure
 422 //
 423 int mops_ip_option_ra (struct mops* mp, int value)
 424 {
 425         int ptr;
 426         u_int16_t val;
 427
 428         if ((mp==NULL) || (value>0xffff)) return 1;
 429
 430         val = (u_int16_t) value;
 431
 432         ptr = mp->ip_option_s; // add option at the end of existing option list (if any)
 433         mp->ip_option_used=20;
 434
 435         // create option header
 436         mp->ip_option[ptr] = 0x94;
 437
 438         ptr++;
 439         mp->ip_option[ptr] = 0x04;
 440
 441         ptr++;
 442         mops_hton2 (&val, &mp->ip_option[ptr]);
 443         ptr+=2;
 444         mp->ip_option_s=4;
 445
 446         return 0;
 447 }