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      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 #ifndef lint
     23 static const char rcsid[] _U_ =
     24     "@(#) $Header: /tcpdump/master/tcpdump/util.c,v 1.109 2007-01-29 09:59:42 hannes Exp $ (LBL)";
     25 #endif
     26 
     27 #ifdef HAVE_CONFIG_H
     28 #include "config.h"
     29 #endif
     30 
     31 #include <tcpdump-stdinc.h>
     32 
     33 #include <sys/stat.h>
     34 
     35 #include <errno.h>
     36 #ifdef HAVE_FCNTL_H
     37 #include <fcntl.h>
     38 #endif
     39 #include <pcap.h>
     40 #include <stdio.h>
     41 #include <stdarg.h>
     42 #include <stdlib.h>
     43 #include <string.h>
     44 
     45 #include "interface.h"
     46 
     47 char * ts_format(register int, register int);
     48 
     49 /*
     50  * Print out a null-terminated filename (or other ascii string).
     51  * If ep is NULL, assume no truncation check is needed.
     52  * Return true if truncated.
     53  */
     54 int
     55 fn_print(register const u_char *s, register const u_char *ep)
     56 {
     57 	register int ret;
     58 	register u_char c;
     59 
     60 	ret = 1;			/* assume truncated */
     61 	while (ep == NULL || s < ep) {
     62 		c = *s++;
     63 		if (c == '\0') {
     64 			ret = 0;
     65 			break;
     66 		}
     67 		if (!ND_ISASCII(c)) {
     68 			c = ND_TOASCII(c);
     69 			putchar('M');
     70 			putchar('-');
     71 		}
     72 		if (!ND_ISPRINT(c)) {
     73 			c ^= 0x40;	/* DEL to ?, others to alpha */
     74 			putchar('^');
     75 		}
     76 		putchar(c);
     77 	}
     78 	return(ret);
     79 }
     80 
     81 /*
     82  * Print out a counted filename (or other ascii string).
     83  * If ep is NULL, assume no truncation check is needed.
     84  * Return true if truncated.
     85  */
     86 int
     87 fn_printn(register const u_char *s, register u_int n,
     88 	  register const u_char *ep)
     89 {
     90 	register u_char c;
     91 
     92 	while (n > 0 && (ep == NULL || s < ep)) {
     93 		n--;
     94 		c = *s++;
     95 		if (!ND_ISASCII(c)) {
     96 			c = ND_TOASCII(c);
     97 			putchar('M');
     98 			putchar('-');
     99 		}
    100 		if (!ND_ISPRINT(c)) {
    101 			c ^= 0x40;	/* DEL to ?, others to alpha */
    102 			putchar('^');
    103 		}
    104 		putchar(c);
    105 	}
    106 	return (n == 0) ? 0 : 1;
    107 }
    108 
    109 /*
    110  * Print out a null-padded filename (or other ascii string).
    111  * If ep is NULL, assume no truncation check is needed.
    112  * Return true if truncated.
    113  */
    114 int
    115 fn_printzp(register const u_char *s, register u_int n,
    116 	  register const u_char *ep)
    117 {
    118 	register int ret;
    119 	register u_char c;
    120 
    121 	ret = 1;			/* assume truncated */
    122 	while (n > 0 && (ep == NULL || s < ep)) {
    123 		n--;
    124 		c = *s++;
    125 		if (c == '\0') {
    126 			ret = 0;
    127 			break;
    128 		}
    129 		if (!ND_ISASCII(c)) {
    130 			c = ND_TOASCII(c);
    131 			putchar('M');
    132 			putchar('-');
    133 		}
    134 		if (!ND_ISPRINT(c)) {
    135 			c ^= 0x40;	/* DEL to ?, others to alpha */
    136 			putchar('^');
    137 		}
    138 		putchar(c);
    139 	}
    140 	return (n == 0) ? 0 : ret;
    141 }
    142 
    143 /*
    144  * Format the timestamp
    145  */
    146 char *
    147 ts_format(register int sec, register int usec)
    148 {
    149         static char buf[sizeof("00:00:00.000000")];
    150         (void)snprintf(buf, sizeof(buf), "%02d:%02d:%02d.%06u",
    151                sec / 3600, (sec % 3600) / 60, sec % 60, usec);
    152 
    153         return buf;
    154 }
    155 
    156 /*
    157  * Print the timestamp
    158  */
    159 void
    160 ts_print(register const struct timeval *tvp)
    161 {
    162 	register int s;
    163 	struct tm *tm;
    164 	time_t Time;
    165 	static unsigned b_sec;
    166 	static unsigned b_usec;
    167 	int d_usec;
    168 	int d_sec;
    169 
    170 	switch (tflag) {
    171 
    172 	case 0: /* Default */
    173 		s = (tvp->tv_sec + thiszone) % 86400;
    174                 (void)printf("%s ", ts_format(s, tvp->tv_usec));
    175 		break;
    176 
    177 	case 1: /* No time stamp */
    178 		break;
    179 
    180 	case 2: /* Unix timeval style */
    181 		(void)printf("%u.%06u ",
    182 			     (unsigned)tvp->tv_sec,
    183 			     (unsigned)tvp->tv_usec);
    184 		break;
    185 
    186 	case 3: /* Microseconds since previous packet */
    187         case 5: /* Microseconds since first packet */
    188 		if (b_sec == 0) {
    189                         /* init timestamp for first packet */
    190                         b_usec = tvp->tv_usec;
    191                         b_sec = tvp->tv_sec;
    192                 }
    193 
    194                 d_usec = tvp->tv_usec - b_usec;
    195                 d_sec = tvp->tv_sec - b_sec;
    196 
    197                 while (d_usec < 0) {
    198                     d_usec += 1000000;
    199                     d_sec--;
    200                 }
    201 
    202                 (void)printf("%s ", ts_format(d_sec, d_usec));
    203 
    204                 if (tflag == 3) { /* set timestamp for last packet */
    205                     b_sec = tvp->tv_sec;
    206                     b_usec = tvp->tv_usec;
    207                 }
    208 		break;
    209 
    210 	case 4: /* Default + Date*/
    211 		s = (tvp->tv_sec + thiszone) % 86400;
    212 		Time = (tvp->tv_sec + thiszone) - s;
    213 		tm = gmtime (&Time);
    214 		if (!tm)
    215 			printf("Date fail  ");
    216 		else
    217 			printf("%04d-%02d-%02d %s ",
    218                                tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
    219                                ts_format(s, tvp->tv_usec));
    220 		break;
    221 	}
    222 }
    223 
    224 /*
    225  * Print a relative number of seconds (e.g. hold time, prune timer)
    226  * in the form 5m1s.  This does no truncation, so 32230861 seconds
    227  * is represented as 1y1w1d1h1m1s.
    228  */
    229 void
    230 relts_print(int secs)
    231 {
    232 	static const char *lengths[] = {"y", "w", "d", "h", "m", "s"};
    233 	static const int seconds[] = {31536000, 604800, 86400, 3600, 60, 1};
    234 	const char **l = lengths;
    235 	const int *s = seconds;
    236 
    237 	if (secs == 0) {
    238 		(void)printf("0s");
    239 		return;
    240 	}
    241 	if (secs < 0) {
    242 		(void)printf("-");
    243 		secs = -secs;
    244 	}
    245 	while (secs > 0) {
    246 		if (secs >= *s) {
    247 			(void)printf("%d%s", secs / *s, *l);
    248 			secs -= (secs / *s) * *s;
    249 		}
    250 		s++;
    251 		l++;
    252 	}
    253 }
    254 
    255 /*
    256  *  this is a generic routine for printing unknown data;
    257  *  we pass on the linefeed plus indentation string to
    258  *  get a proper output - returns 0 on error
    259  */
    260 
    261 int
    262 print_unknown_data(const u_char *cp,const char *ident,int len)
    263 {
    264 	if (len < 0) {
    265 		printf("%sDissector error: print_unknown_data called with negative length",
    266 		    ident);
    267 		return(0);
    268 	}
    269 	if (snapend - cp < len)
    270 		len = snapend - cp;
    271 	if (len < 0) {
    272 		printf("%sDissector error: print_unknown_data called with pointer past end of packet",
    273 		    ident);
    274 		return(0);
    275 	}
    276         hex_print(ident,cp,len);
    277 	return(1); /* everything is ok */
    278 }
    279 
    280 /*
    281  * Convert a token value to a string; use "fmt" if not found.
    282  */
    283 const char *
    284 tok2strbuf(register const struct tok *lp, register const char *fmt,
    285 	   register int v, char *buf, size_t bufsize)
    286 {
    287 	if (lp != NULL) {
    288 		while (lp->s != NULL) {
    289 			if (lp->v == v)
    290 				return (lp->s);
    291 			++lp;
    292 		}
    293 	}
    294 	if (fmt == NULL)
    295 		fmt = "#%d";
    296 
    297 	(void)snprintf(buf, bufsize, fmt, v);
    298 	return (const char *)buf;
    299 }
    300 
    301 /*
    302  * Convert a token value to a string; use "fmt" if not found.
    303  */
    304 const char *
    305 tok2str(register const struct tok *lp, register const char *fmt,
    306 	register int v)
    307 {
    308 	static char buf[4][128];
    309 	static int idx = 0;
    310 	char *ret;
    311 
    312 	ret = buf[idx];
    313 	idx = (idx+1) & 3;
    314 	return tok2strbuf(lp, fmt, v, ret, sizeof(buf[0]));
    315 }
    316 
    317 /*
    318  * Convert a bit token value to a string; use "fmt" if not found.
    319  * this is useful for parsing bitfields, the output strings are seperated
    320  * if the s field is positive.
    321  */
    322 static char *
    323 bittok2str_internal(register const struct tok *lp, register const char *fmt,
    324 	   register int v, register int sep)
    325 {
    326         static char buf[256]; /* our stringbuffer */
    327         int buflen=0;
    328         register int rotbit; /* this is the bit we rotate through all bitpositions */
    329         register int tokval;
    330 
    331 	while (lp != NULL && lp->s != NULL) {
    332             tokval=lp->v;   /* load our first value */
    333             rotbit=1;
    334             while (rotbit != 0) {
    335                 /*
    336                  * lets AND the rotating bit with our token value
    337                  * and see if we have got a match
    338                  */
    339 		if (tokval == (v&rotbit)) {
    340                     /* ok we have found something */
    341                     buflen+=snprintf(buf+buflen, sizeof(buf)-buflen, "%s%s",
    342                                      lp->s, sep ? ", " : "");
    343                     break;
    344                 }
    345                 rotbit=rotbit<<1; /* no match - lets shift and try again */
    346             }
    347             lp++;
    348 	}
    349 
    350         /* user didn't want string seperation - no need to cut off trailing seperators */
    351         if (!sep) {
    352             return (buf);
    353         }
    354 
    355         if (buflen != 0) { /* did we find anything */
    356             /* yep, set the the trailing zero 2 bytes before to eliminate the last comma & whitespace */
    357             buf[buflen-2] = '\0';
    358             return (buf);
    359         }
    360         else {
    361             /* bummer - lets print the "unknown" message as advised in the fmt string if we got one */
    362             if (fmt == NULL)
    363 		fmt = "#%d";
    364             (void)snprintf(buf, sizeof(buf), fmt, v);
    365             return (buf);
    366         }
    367 }
    368 
    369 /*
    370  * Convert a bit token value to a string; use "fmt" if not found.
    371  * this is useful for parsing bitfields, the output strings are not seperated.
    372  */
    373 char *
    374 bittok2str_nosep(register const struct tok *lp, register const char *fmt,
    375 	   register int v)
    376 {
    377     return (bittok2str_internal(lp, fmt, v, 0));
    378 }
    379 
    380 /*
    381  * Convert a bit token value to a string; use "fmt" if not found.
    382  * this is useful for parsing bitfields, the output strings are comma seperated.
    383  */
    384 char *
    385 bittok2str(register const struct tok *lp, register const char *fmt,
    386 	   register int v)
    387 {
    388     return (bittok2str_internal(lp, fmt, v, 1));
    389 }
    390 
    391 /*
    392  * Convert a value to a string using an array; the macro
    393  * tok2strary() in <interface.h> is the public interface to
    394  * this function and ensures that the second argument is
    395  * correct for bounds-checking.
    396  */
    397 const char *
    398 tok2strary_internal(register const char **lp, int n, register const char *fmt,
    399 	register int v)
    400 {
    401 	static char buf[128];
    402 
    403 	if (v >= 0 && v < n && lp[v] != NULL)
    404 		return lp[v];
    405 	if (fmt == NULL)
    406 		fmt = "#%d";
    407 	(void)snprintf(buf, sizeof(buf), fmt, v);
    408 	return (buf);
    409 }
    410 
    411 /*
    412  * Convert a 32-bit netmask to prefixlen if possible
    413  * the function returns the prefix-len; if plen == -1
    414  * then conversion was not possible;
    415  */
    416 
    417 int
    418 mask2plen(u_int32_t mask)
    419 {
    420 	u_int32_t bitmasks[33] = {
    421 		0x00000000,
    422 		0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
    423 		0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
    424 		0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
    425 		0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
    426 		0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
    427 		0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
    428 		0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
    429 		0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
    430 	};
    431 	int prefix_len = 32;
    432 
    433 	/* let's see if we can transform the mask into a prefixlen */
    434 	while (prefix_len >= 0) {
    435 		if (bitmasks[prefix_len] == mask)
    436 			break;
    437 		prefix_len--;
    438 	}
    439 	return (prefix_len);
    440 }
    441 
    442 #ifdef INET6
    443 int
    444 mask62plen(const u_char *mask)
    445 {
    446 	u_char bitmasks[9] = {
    447 		0x00,
    448 		0x80, 0xc0, 0xe0, 0xf0,
    449 		0xf8, 0xfc, 0xfe, 0xff
    450 	};
    451 	int byte;
    452 	int cidr_len = 0;
    453 
    454 	for (byte = 0; byte < 16; byte++) {
    455 		u_int bits;
    456 
    457 		for (bits = 0; bits < (sizeof (bitmasks) / sizeof (bitmasks[0])); bits++) {
    458 			if (mask[byte] == bitmasks[bits]) {
    459 				cidr_len += bits;
    460 				break;
    461 			}
    462 		}
    463 
    464 		if (mask[byte] != 0xff)
    465 			break;
    466 	}
    467 	return (cidr_len);
    468 }
    469 #endif /* INET6 */
    470 
    471 /* VARARGS */
    472 void
    473 error(const char *fmt, ...)
    474 {
    475 	va_list ap;
    476 
    477 	(void)fprintf(stderr, "%s: ", program_name);
    478 	va_start(ap, fmt);
    479 	(void)vfprintf(stderr, fmt, ap);
    480 	va_end(ap);
    481 	if (*fmt) {
    482 		fmt += strlen(fmt);
    483 		if (fmt[-1] != '\n')
    484 			(void)fputc('\n', stderr);
    485 	}
    486 	exit(1);
    487 	/* NOTREACHED */
    488 }
    489 
    490 /* VARARGS */
    491 void
    492 warning(const char *fmt, ...)
    493 {
    494 	va_list ap;
    495 
    496 	(void)fprintf(stderr, "%s: WARNING: ", program_name);
    497 	va_start(ap, fmt);
    498 	(void)vfprintf(stderr, fmt, ap);
    499 	va_end(ap);
    500 	if (*fmt) {
    501 		fmt += strlen(fmt);
    502 		if (fmt[-1] != '\n')
    503 			(void)fputc('\n', stderr);
    504 	}
    505 }
    506 
    507 /*
    508  * Copy arg vector into a new buffer, concatenating arguments with spaces.
    509  */
    510 char *
    511 copy_argv(register char **argv)
    512 {
    513 	register char **p;
    514 	register u_int len = 0;
    515 	char *buf;
    516 	char *src, *dst;
    517 
    518 	p = argv;
    519 	if (*p == 0)
    520 		return 0;
    521 
    522 	while (*p)
    523 		len += strlen(*p++) + 1;
    524 
    525 	buf = (char *)malloc(len);
    526 	if (buf == NULL)
    527 		error("copy_argv: malloc");
    528 
    529 	p = argv;
    530 	dst = buf;
    531 	while ((src = *p++) != NULL) {
    532 		while ((*dst++ = *src++) != '\0')
    533 			;
    534 		dst[-1] = ' ';
    535 	}
    536 	dst[-1] = '\0';
    537 
    538 	return buf;
    539 }
    540 
    541 /*
    542  * On Windows, we need to open the file in binary mode, so that
    543  * we get all the bytes specified by the size we get from "fstat()".
    544  * On UNIX, that's not necessary.  O_BINARY is defined on Windows;
    545  * we define it as 0 if it's not defined, so it does nothing.
    546  */
    547 #ifndef O_BINARY
    548 #define O_BINARY	0
    549 #endif
    550 
    551 char *
    552 read_infile(char *fname)
    553 {
    554 	register int i, fd, cc;
    555 	register char *cp;
    556 	struct stat buf;
    557 
    558 	fd = open(fname, O_RDONLY|O_BINARY);
    559 	if (fd < 0)
    560 		error("can't open %s: %s", fname, pcap_strerror(errno));
    561 
    562 	if (fstat(fd, &buf) < 0)
    563 		error("can't stat %s: %s", fname, pcap_strerror(errno));
    564 
    565 	cp = malloc((u_int)buf.st_size + 1);
    566 	if (cp == NULL)
    567 		error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
    568 			fname, pcap_strerror(errno));
    569 	cc = read(fd, cp, (u_int)buf.st_size);
    570 	if (cc < 0)
    571 		error("read %s: %s", fname, pcap_strerror(errno));
    572 	if (cc != buf.st_size)
    573 		error("short read %s (%d != %d)", fname, cc, (int)buf.st_size);
    574 
    575 	close(fd);
    576 	/* replace "# comment" with spaces */
    577 	for (i = 0; i < cc; i++) {
    578 		if (cp[i] == '#')
    579 			while (i < cc && cp[i] != '\n')
    580 				cp[i++] = ' ';
    581 	}
    582 	cp[cc] = '\0';
    583 	return (cp);
    584 }
    585 
    586 void
    587 safeputs(const char *s, int maxlen)
    588 {
    589 	int idx = 0;
    590 
    591 	while (*s && idx < maxlen) {
    592 		safeputchar(*s);
    593                 idx++;
    594 		s++;
    595 	}
    596 }
    597 
    598 void
    599 safeputchar(int c)
    600 {
    601 	unsigned char ch;
    602 
    603 	ch = (unsigned char)(c & 0xff);
    604 	if (ch < 0x80 && ND_ISPRINT(ch))
    605 		printf("%c", ch);
    606 	else
    607 		printf("\\0x%02x", ch);
    608 }
    609 
    610 #ifdef LBL_ALIGN
    611 /*
    612  * Some compilers try to optimize memcpy(), using the alignment constraint
    613  * on the argument pointer type.  by using this function, we try to avoid the
    614  * optimization.
    615  */
    616 void
    617 unaligned_memcpy(void *p, const void *q, size_t l)
    618 {
    619 	memcpy(p, q, l);
    620 }
    621 
    622 /* As with memcpy(), so with memcmp(). */
    623 int
    624 unaligned_memcmp(const void *p, const void *q, size_t l)
    625 {
    626 	return (memcmp(p, q, l));
    627 }
    628 #endif
    629