The Tcpdump Group git mirrors - tcpdump/blob - util.c

   1 /*
   2  * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <tcpdump-stdinc.h>
  27
  28 #include <sys/stat.h>
  29
  30 #include <errno.h>
  31 #ifdef HAVE_FCNTL_H
  32 #include <fcntl.h>
  33 #endif
  34 #include <stdio.h>
  35 #include <stdarg.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include "interface.h"
  40
  41 /*
  42  * Print out a null-terminated filename (or other ascii string).
  43  * If ep is NULL, assume no truncation check is needed.
  44  * Return true if truncated.
  45  */
  46 int
  47 fn_print(register const u_char *s, register const u_char *ep)
  48 {
  49         register int ret;
  50         register u_char c;
  51
  52         ret = 1;                        /* assume truncated */
  53         while (ep == NULL || s < ep) {
  54                 c = *s++;
  55                 if (c == '\0') {
  56                         ret = 0;
  57                         break;
  58                 }
  59                 if (!ND_ISASCII(c)) {
  60                         c = ND_TOASCII(c);
  61                         putchar('M');
  62                         putchar('-');
  63                 }
  64                 if (!ND_ISPRINT(c)) {
  65                         c ^= 0x40;      /* DEL to ?, others to alpha */
  66                         putchar('^');
  67                 }
  68                 putchar(c);
  69         }
  70         return(ret);
  71 }
  72
  73 /*
  74  * Print out a counted filename (or other ascii string).
  75  * If ep is NULL, assume no truncation check is needed.
  76  * Return true if truncated.
  77  */
  78 int
  79 fn_printn(register const u_char *s, register u_int n,
  80           register const u_char *ep)
  81 {
  82         register u_char c;
  83
  84         while (n > 0 && (ep == NULL || s < ep)) {
  85                 n--;
  86                 c = *s++;
  87                 if (!ND_ISASCII(c)) {
  88                         c = ND_TOASCII(c);
  89                         putchar('M');
  90                         putchar('-');
  91                 }
  92                 if (!ND_ISPRINT(c)) {
  93                         c ^= 0x40;      /* DEL to ?, others to alpha */
  94                         putchar('^');
  95                 }
  96                 putchar(c);
  97         }
  98         return (n == 0) ? 0 : 1;
  99 }
 100
 101 /*
 102  * Print out a null-padded filename (or other ascii string).
 103  * If ep is NULL, assume no truncation check is needed.
 104  * Return true if truncated.
 105  */
 106 int
 107 fn_printzp(register const u_char *s, register u_int n,
 108           register const u_char *ep)
 109 {
 110         register int ret;
 111         register u_char c;
 112
 113         ret = 1;                        /* assume truncated */
 114         while (n > 0 && (ep == NULL || s < ep)) {
 115                 n--;
 116                 c = *s++;
 117                 if (c == '\0') {
 118                         ret = 0;
 119                         break;
 120                 }
 121                 if (!ND_ISASCII(c)) {
 122                         c = ND_TOASCII(c);
 123                         putchar('M');
 124                         putchar('-');
 125                 }
 126                 if (!ND_ISPRINT(c)) {
 127                         c ^= 0x40;      /* DEL to ?, others to alpha */
 128                         putchar('^');
 129                 }
 130                 putchar(c);
 131         }
 132         return (n == 0) ? 0 : ret;
 133 }
 134
 135 /*
 136  * Format the timestamp
 137  */
 138 static char *
 139 ts_format(register int sec, register int usec)
 140 {
 141         static char buf[sizeof("00:00:00.000000")];
 142         (void)snprintf(buf, sizeof(buf), "%02d:%02d:%02d.%06u",
 143                sec / 3600, (sec % 3600) / 60, sec % 60, usec);
 144
 145         return buf;
 146 }
 147
 148 /*
 149  * Print the timestamp
 150  */
 151 void
 152 ts_print(netdissect_options *ndo,
 153          register const struct timeval *tvp)
 154 {
 155         register int s;
 156         struct tm *tm;
 157         time_t Time;
 158         static unsigned b_sec;
 159         static unsigned b_usec;
 160         int d_usec;
 161         int d_sec;
 162
 163         switch (ndo->ndo_tflag) {
 164
 165         case 0: /* Default */
 166                 s = (tvp->tv_sec + thiszone) % 86400;
 167                 ND_PRINT((ndo, "%s ", ts_format(s, tvp->tv_usec)));
 168                 break;
 169
 170         case 1: /* No time stamp */
 171                 break;
 172
 173         case 2: /* Unix timeval style */
 174                 ND_PRINT((ndo, "%u.%06u ",
 175                              (unsigned)tvp->tv_sec,
 176                              (unsigned)tvp->tv_usec));
 177                 break;
 178
 179         case 3: /* Microseconds since previous packet */
 180         case 5: /* Microseconds since first packet */
 181                 if (b_sec == 0) {
 182                         /* init timestamp for first packet */
 183                         b_usec = tvp->tv_usec;
 184                         b_sec = tvp->tv_sec;
 185                 }
 186
 187                 d_usec = tvp->tv_usec - b_usec;
 188                 d_sec = tvp->tv_sec - b_sec;
 189
 190                 while (d_usec < 0) {
 191                     d_usec += 1000000;
 192                     d_sec--;
 193                 }
 194
 195                 ND_PRINT((ndo, "%s ", ts_format(d_sec, d_usec)));
 196
 197                 if (ndo->ndo_tflag == 3) { /* set timestamp for last packet */
 198                     b_sec = tvp->tv_sec;
 199                     b_usec = tvp->tv_usec;
 200                 }
 201                 break;
 202
 203         case 4: /* Default + Date*/
 204                 s = (tvp->tv_sec + thiszone) % 86400;
 205                 Time = (tvp->tv_sec + thiszone) - s;
 206                 tm = gmtime (&Time);
 207                 if (!tm)
 208                         ND_PRINT((ndo, "Date fail  "));
 209                 else
 210                         ND_PRINT((ndo, "%04d-%02d-%02d %s ",
 211                                tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
 212                                ts_format(s, tvp->tv_usec)));
 213                 break;
 214         }
 215 }
 216
 217 /*
 218  * Print a relative number of seconds (e.g. hold time, prune timer)
 219  * in the form 5m1s.  This does no truncation, so 32230861 seconds
 220  * is represented as 1y1w1d1h1m1s.
 221  */
 222 void
 223 relts_print(netdissect_options *ndo,
 224             int secs)
 225 {
 226         static const char *lengths[] = {"y", "w", "d", "h", "m", "s"};
 227         static const int seconds[] = {31536000, 604800, 86400, 3600, 60, 1};
 228         const char **l = lengths;
 229         const int *s = seconds;
 230
 231         if (secs == 0) {
 232                 ND_PRINT((ndo, "0s"));
 233                 return;
 234         }
 235         if (secs < 0) {
 236                 ND_PRINT((ndo, "-"));
 237                 secs = -secs;
 238         }
 239         while (secs > 0) {
 240                 if (secs >= *s) {
 241                         ND_PRINT((ndo, "%d%s", secs / *s, *l));
 242                         secs -= (secs / *s) * *s;
 243                 }
 244                 s++;
 245                 l++;
 246         }
 247 }
 248
 249 /*
 250  *  this is a generic routine for printing unknown data;
 251  *  we pass on the linefeed plus indentation string to
 252  *  get a proper output - returns 0 on error
 253  */
 254
 255 int
 256 print_unknown_data(netdissect_options *ndo, const u_char *cp,const char *ident,int len)
 257 {
 258         if (len < 0) {
 259           ND_PRINT((ndo,"%sDissector error: print_unknown_data called with negative length",
 260                     ident));
 261                 return(0);
 262         }
 263         if (ndo->ndo_snapend - cp < len)
 264                 len = ndo->ndo_snapend - cp;
 265         if (len < 0) {
 266           ND_PRINT((ndo,"%sDissector error: print_unknown_data called with pointer past end of packet",
 267                     ident));
 268                 return(0);
 269         }
 270         hex_print(ndo, ident,cp,len);
 271         return(1); /* everything is ok */
 272 }
 273
 274 /*
 275  * Convert a token value to a string; use "fmt" if not found.
 276  */
 277 const char *
 278 tok2strbuf(register const struct tok *lp, register const char *fmt,
 279            register u_int v, char *buf, size_t bufsize)
 280 {
 281         if (lp != NULL) {
 282                 while (lp->s != NULL) {
 283                         if (lp->v == v)
 284                                 return (lp->s);
 285                         ++lp;
 286                 }
 287         }
 288         if (fmt == NULL)
 289                 fmt = "#%d";
 290
 291         (void)snprintf(buf, bufsize, fmt, v);
 292         return (const char *)buf;
 293 }
 294
 295 /*
 296  * Convert a token value to a string; use "fmt" if not found.
 297  */
 298 const char *
 299 tok2str(register const struct tok *lp, register const char *fmt,
 300         register int v)
 301 {
 302         static char buf[4][128];
 303         static int idx = 0;
 304         char *ret;
 305
 306         ret = buf[idx];
 307         idx = (idx+1) & 3;
 308         return tok2strbuf(lp, fmt, v, ret, sizeof(buf[0]));
 309 }
 310
 311 /*
 312  * Convert a bit token value to a string; use "fmt" if not found.
 313  * this is useful for parsing bitfields, the output strings are seperated
 314  * if the s field is positive.
 315  */
 316 static char *
 317 bittok2str_internal(register const struct tok *lp, register const char *fmt,
 318            register int v, register int sep)
 319 {
 320         static char buf[256]; /* our stringbuffer */
 321         int buflen=0;
 322         register int rotbit; /* this is the bit we rotate through all bitpositions */
 323         register int tokval;
 324
 325         while (lp != NULL && lp->s != NULL) {
 326             tokval=lp->v;   /* load our first value */
 327             rotbit=1;
 328             while (rotbit != 0) {
 329                 /*
 330                  * lets AND the rotating bit with our token value
 331                  * and see if we have got a match
 332                  */
 333                 if (tokval == (v&rotbit)) {
 334                     /* ok we have found something */
 335                     buflen+=snprintf(buf+buflen, sizeof(buf)-buflen, "%s%s",
 336                                      lp->s, sep ? ", " : "");
 337                     break;
 338                 }
 339                 rotbit=rotbit<<1; /* no match - lets shift and try again */
 340             }
 341             lp++;
 342         }
 343
 344         /* user didn't want string seperation - no need to cut off trailing seperators */
 345         if (!sep) {
 346             return (buf);
 347         }
 348
 349         if (buflen != 0) { /* did we find anything */
 350             /* yep, set the trailing zero 2 bytes before to eliminate the last comma & whitespace */
 351             buf[buflen-2] = '\0';
 352             return (buf);
 353         }
 354         else {
 355             /* bummer - lets print the "unknown" message as advised in the fmt string if we got one */
 356             if (fmt == NULL)
 357                 fmt = "#%d";
 358             (void)snprintf(buf, sizeof(buf), fmt, v);
 359             return (buf);
 360         }
 361 }
 362
 363 /*
 364  * Convert a bit token value to a string; use "fmt" if not found.
 365  * this is useful for parsing bitfields, the output strings are not seperated.
 366  */
 367 char *
 368 bittok2str_nosep(register const struct tok *lp, register const char *fmt,
 369            register int v)
 370 {
 371     return (bittok2str_internal(lp, fmt, v, 0));
 372 }
 373
 374 /*
 375  * Convert a bit token value to a string; use "fmt" if not found.
 376  * this is useful for parsing bitfields, the output strings are comma seperated.
 377  */
 378 char *
 379 bittok2str(register const struct tok *lp, register const char *fmt,
 380            register int v)
 381 {
 382     return (bittok2str_internal(lp, fmt, v, 1));
 383 }
 384
 385 /*
 386  * Convert a value to a string using an array; the macro
 387  * tok2strary() in <interface.h> is the public interface to
 388  * this function and ensures that the second argument is
 389  * correct for bounds-checking.
 390  */
 391 const char *
 392 tok2strary_internal(register const char **lp, int n, register const char *fmt,
 393         register int v)
 394 {
 395         static char buf[128];
 396
 397         if (v >= 0 && v < n && lp[v] != NULL)
 398                 return lp[v];
 399         if (fmt == NULL)
 400                 fmt = "#%d";
 401         (void)snprintf(buf, sizeof(buf), fmt, v);
 402         return (buf);
 403 }
 404
 405 /*
 406  * Convert a 32-bit netmask to prefixlen if possible
 407  * the function returns the prefix-len; if plen == -1
 408  * then conversion was not possible;
 409  */
 410
 411 int
 412 mask2plen(u_int32_t mask)
 413 {
 414         u_int32_t bitmasks[33] = {
 415                 0x00000000,
 416                 0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
 417                 0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
 418                 0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
 419                 0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
 420                 0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
 421                 0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
 422                 0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
 423                 0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
 424         };
 425         int prefix_len = 32;
 426
 427         /* let's see if we can transform the mask into a prefixlen */
 428         while (prefix_len >= 0) {
 429                 if (bitmasks[prefix_len] == mask)
 430                         break;
 431                 prefix_len--;
 432         }
 433         return (prefix_len);
 434 }
 435
 436 #ifdef INET6
 437 int
 438 mask62plen(const u_char *mask)
 439 {
 440         u_char bitmasks[9] = {
 441                 0x00,
 442                 0x80, 0xc0, 0xe0, 0xf0,
 443                 0xf8, 0xfc, 0xfe, 0xff
 444         };
 445         int byte;
 446         int cidr_len = 0;
 447
 448         for (byte = 0; byte < 16; byte++) {
 449                 u_int bits;
 450
 451                 for (bits = 0; bits < (sizeof (bitmasks) / sizeof (bitmasks[0])); bits++) {
 452                         if (mask[byte] == bitmasks[bits]) {
 453                                 cidr_len += bits;
 454                                 break;
 455                         }
 456                 }
 457
 458                 if (mask[byte] != 0xff)
 459                         break;
 460         }
 461         return (cidr_len);
 462 }
 463 #endif /* INET6 */
 464
 465 /* VARARGS */
 466 void
 467 error(const char *fmt, ...)
 468 {
 469         va_list ap;
 470
 471         (void)fprintf(stderr, "%s: ", program_name);
 472         va_start(ap, fmt);
 473         (void)vfprintf(stderr, fmt, ap);
 474         va_end(ap);
 475         if (*fmt) {
 476                 fmt += strlen(fmt);
 477                 if (fmt[-1] != '\n')
 478                         (void)fputc('\n', stderr);
 479         }
 480         exit(1);
 481         /* NOTREACHED */
 482 }
 483
 484 /* VARARGS */
 485 void
 486 warning(const char *fmt, ...)
 487 {
 488         va_list ap;
 489
 490         (void)fprintf(stderr, "%s: WARNING: ", program_name);
 491         va_start(ap, fmt);
 492         (void)vfprintf(stderr, fmt, ap);
 493         va_end(ap);
 494         if (*fmt) {
 495                 fmt += strlen(fmt);
 496                 if (fmt[-1] != '\n')
 497                         (void)fputc('\n', stderr);
 498         }
 499 }
 500
 501 /*
 502  * Copy arg vector into a new buffer, concatenating arguments with spaces.
 503  */
 504 char *
 505 copy_argv(register char **argv)
 506 {
 507         register char **p;
 508         register u_int len = 0;
 509         char *buf;
 510         char *src, *dst;
 511
 512         p = argv;
 513         if (*p == 0)
 514                 return 0;
 515
 516         while (*p)
 517                 len += strlen(*p++) + 1;
 518
 519         buf = (char *)malloc(len);
 520         if (buf == NULL)
 521                 error("copy_argv: malloc");
 522
 523         p = argv;
 524         dst = buf;
 525         while ((src = *p++) != NULL) {
 526                 while ((*dst++ = *src++) != '\0')
 527                         ;
 528                 dst[-1] = ' ';
 529         }
 530         dst[-1] = '\0';
 531
 532         return buf;
 533 }
 534
 535 /*
 536  * On Windows, we need to open the file in binary mode, so that
 537  * we get all the bytes specified by the size we get from "fstat()".
 538  * On UNIX, that's not necessary.  O_BINARY is defined on Windows;
 539  * we define it as 0 if it's not defined, so it does nothing.
 540  */
 541 #ifndef O_BINARY
 542 #define O_BINARY        0
 543 #endif
 544
 545 char *
 546 read_infile(char *fname)
 547 {
 548         register int i, fd, cc;
 549         register char *cp;
 550         struct stat buf;
 551
 552         fd = open(fname, O_RDONLY|O_BINARY);
 553         if (fd < 0)
 554                 error("can't open %s: %s", fname, pcap_strerror(errno));
 555
 556         if (fstat(fd, &buf) < 0)
 557                 error("can't stat %s: %s", fname, pcap_strerror(errno));
 558
 559         cp = malloc((u_int)buf.st_size + 1);
 560         if (cp == NULL)
 561                 error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
 562                         fname, pcap_strerror(errno));
 563         cc = read(fd, cp, (u_int)buf.st_size);
 564         if (cc < 0)
 565                 error("read %s: %s", fname, pcap_strerror(errno));
 566         if (cc != buf.st_size)
 567                 error("short read %s (%d != %d)", fname, cc, (int)buf.st_size);
 568
 569         close(fd);
 570         /* replace "# comment" with spaces */
 571         for (i = 0; i < cc; i++) {
 572                 if (cp[i] == '#')
 573                         while (i < cc && cp[i] != '\n')
 574                                 cp[i++] = ' ';
 575         }
 576         cp[cc] = '\0';
 577         return (cp);
 578 }
 579
 580 void
 581 safeputs(netdissect_options *ndo,
 582          const u_char *s, const u_int maxlen)
 583 {
 584         u_int idx = 0;
 585
 586         while (*s && idx < maxlen) {
 587                 safeputchar(ndo, *s);
 588                 idx++;
 589                 s++;
 590         }
 591 }
 592
 593 void
 594 safeputchar(netdissect_options *ndo,
 595             const u_char c)
 596 {
 597         ND_PRINT((ndo, (c < 0x80 && ND_ISPRINT(c)) ? "%c" : "\\0x%02x", c));
 598 }
 599
 600 #ifdef LBL_ALIGN
 601 /*
 602  * Some compilers try to optimize memcpy(), using the alignment constraint
 603  * on the argument pointer type.  by using this function, we try to avoid the
 604  * optimization.
 605  */
 606 void
 607 unaligned_memcpy(void *p, const void *q, size_t l)
 608 {
 609         memcpy(p, q, l);
 610 }
 611
 612 /* As with memcpy(), so with memcmp(). */
 613 int
 614 unaligned_memcmp(const void *p, const void *q, size_t l)
 615 {
 616         return (memcmp(p, q, l));
 617 }
 618 #endif