2 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
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
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.
23 * txtproto_print() derived from original code by Hannes Gredler
24 * (hannes@gredler.at):
26 * Redistribution and use in source and binary forms, with or without
27 * modification, are permitted provided that: (1) source code
28 * distributions retain the above copyright notice and this paragraph
29 * in its entirety, and (2) distributions including binary code include
30 * the above copyright notice and this paragraph in its entirety in
31 * the documentation or other materials provided with the distribution.
32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
33 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
34 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
35 * FOR A PARTICULAR PURPOSE.
42 #include "netdissect-stdinc.h"
54 #include "netdissect-ctype.h"
56 #include "netdissect.h"
58 #include "ascii_strcasecmp.h"
59 #include "timeval-operations.h"
61 #define TOKBUFSIZE 128
63 enum date_flag
{ WITHOUT_DATE
= 0, WITH_DATE
= 1 };
64 enum time_flag
{ UTC_TIME
= 0, LOCAL_TIME
= 1 };
67 * Print out a character, filtering out the non-printable ones
70 fn_print_char(netdissect_options
*ndo
, u_char c
)
76 if (!ND_ASCII_ISPRINT(c
)) {
77 c
^= 0x40; /* DEL to ?, others to alpha */
84 * Print a null-terminated string, filtering out non-printable characters.
85 * DON'T USE IT with a pointer on the packet buffer because there is no
86 * truncation check. For this use, see the nd_printX() functions below.
89 fn_print_str(netdissect_options
*ndo
, const u_char
*s
)
92 fn_print_char(ndo
, *s
);
98 * Print out a null-terminated filename (or other ASCII string), part of
100 * If ep is NULL, assume no truncation check is needed.
101 * Return true if truncated.
102 * Stop at ep (if given) or before the null char, whichever is first.
105 nd_print(netdissect_options
*ndo
,
106 const u_char
*s
, const u_char
*ep
)
111 ret
= 1; /* assume truncated */
112 while (ep
== NULL
|| s
< ep
) {
119 fn_print_char(ndo
, c
);
125 * Print out a null-terminated filename (or other ASCII string) from
126 * a fixed-length field in the packet buffer, or from what remains of
129 * n is the length of the fixed-length field, or the number of bytes
130 * remaining in the packet based on its on-the-network length.
132 * If ep is non-null, it should point just past the last captured byte
133 * of the packet, e.g. ndo->ndo_snapend. If ep is NULL, we assume no
134 * truncation check, other than the checks of the field length/remaining
135 * packet data length, is needed.
137 * Return the number of bytes of string processed, including the
138 * terminating null, if not truncated; as the terminating null is
139 * included in the count, and as there must be a terminating null,
140 * this will always be non-zero. Return 0 if truncated.
143 nd_printztn(netdissect_options
*ndo
,
144 const u_char
*s
, u_int n
, const u_char
*ep
)
151 if (n
== 0 || (ep
!= NULL
&& s
>= ep
)) {
153 * Truncated. This includes "no null before we
154 * got to the end of the fixed-length buffer or
155 * the end of the packet".
157 * XXX - BOOTP says "null-terminated", which
158 * means the maximum length of the string, in
159 * bytes, is 1 less than the size of the buffer,
160 * as there must always be a terminating null.
174 fn_print_char(ndo
, c
);
180 * Print out a counted filename (or other ASCII string), part of
182 * If ep is NULL, assume no truncation check is needed.
183 * Return true if truncated.
184 * Stop at ep (if given) or after n bytes, whichever is first.
187 nd_printn(netdissect_options
*ndo
,
188 const u_char
*s
, u_int n
, const u_char
*ep
)
192 while (n
> 0 && (ep
== NULL
|| s
< ep
)) {
196 fn_print_char(ndo
, c
);
198 return (n
== 0) ? 0 : 1;
202 * Print out a null-padded filename (or other ASCII string), part of
204 * If ep is NULL, assume no truncation check is needed.
205 * Return true if truncated.
206 * Stop at ep (if given) or after n bytes or before the null char,
207 * whichever is first.
210 nd_printzp(netdissect_options
*ndo
,
211 const u_char
*s
, u_int n
,
217 ret
= 1; /* assume truncated */
218 while (n
> 0 && (ep
== NULL
|| s
< ep
)) {
226 fn_print_char(ndo
, c
);
228 return (n
== 0) ? 0 : ret
;
232 * Print the timestamp .FRAC part (Microseconds/nanoseconds)
235 ts_frac_print(netdissect_options
*ndo
, long usec
)
237 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
238 switch (ndo
->ndo_tstamp_precision
) {
240 case PCAP_TSTAMP_PRECISION_MICRO
:
241 ND_PRINT(".%06u", (unsigned)usec
);
244 case PCAP_TSTAMP_PRECISION_NANO
:
245 ND_PRINT(".%09u", (unsigned)usec
);
249 ND_PRINT(".{unknown}");
253 ND_PRINT(".%06u", (unsigned)usec
);
258 * Print the timestamp as [YY:MM:DD] HH:MM:SS.FRAC.
259 * if time_flag == LOCAL_TIME print local time else UTC/GMT time
260 * if date_flag == WITH_DATE print YY:MM:DD before HH:MM:SS.FRAC
263 ts_date_hmsfrac_print(netdissect_options
*ndo
, long sec
, long usec
,
264 enum date_flag date_flag
, enum time_flag time_flag
)
270 if ((unsigned)sec
& 0x80000000) {
271 ND_PRINT("[Error converting time]");
275 if (time_flag
== LOCAL_TIME
)
276 tm
= localtime(&Time
);
281 ND_PRINT("[Error converting time]");
284 if (date_flag
== WITH_DATE
)
285 strftime(timestr
, sizeof(timestr
), "%Y-%m-%d %H:%M:%S", tm
);
287 strftime(timestr
, sizeof(timestr
), "%H:%M:%S", tm
);
288 ND_PRINT("%s", timestr
);
290 ts_frac_print(ndo
, usec
);
294 * Print the timestamp - Unix timeval style, as SECS.FRAC.
297 ts_unix_print(netdissect_options
*ndo
, long sec
, long usec
)
299 if ((unsigned)sec
& 0x80000000) {
300 ND_PRINT("[Error converting time]");
304 ND_PRINT("%u", (unsigned)sec
);
305 ts_frac_print(ndo
, usec
);
309 * Print the timestamp
312 ts_print(netdissect_options
*ndo
,
313 const struct timeval
*tvp
)
315 static struct timeval tv_ref
;
316 struct timeval tv_result
;
320 switch (ndo
->ndo_tflag
) {
322 case 0: /* Default */
323 ts_date_hmsfrac_print(ndo
, tvp
->tv_sec
, tvp
->tv_usec
,
324 WITHOUT_DATE
, LOCAL_TIME
);
328 case 1: /* No time stamp */
331 case 2: /* Unix timeval style */
332 ts_unix_print(ndo
, tvp
->tv_sec
, tvp
->tv_usec
);
336 case 3: /* Microseconds/nanoseconds since previous packet */
337 case 5: /* Microseconds/nanoseconds since first packet */
338 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
339 switch (ndo
->ndo_tstamp_precision
) {
340 case PCAP_TSTAMP_PRECISION_MICRO
:
343 case PCAP_TSTAMP_PRECISION_NANO
:
353 if (!(netdissect_timevalisset(&tv_ref
)))
354 tv_ref
= *tvp
; /* set timestamp for first packet */
356 negative_offset
= netdissect_timevalcmp(tvp
, &tv_ref
, <);
358 netdissect_timevalsub(&tv_ref
, tvp
, &tv_result
, nano_prec
);
360 netdissect_timevalsub(tvp
, &tv_ref
, &tv_result
, nano_prec
);
362 ND_PRINT((negative_offset
? "-" : " "));
363 ts_date_hmsfrac_print(ndo
, tv_result
.tv_sec
, tv_result
.tv_usec
,
364 WITHOUT_DATE
, UTC_TIME
);
367 if (ndo
->ndo_tflag
== 3)
368 tv_ref
= *tvp
; /* set timestamp for previous packet */
371 case 4: /* Date + Default */
372 ts_date_hmsfrac_print(ndo
, tvp
->tv_sec
, tvp
->tv_usec
,
373 WITH_DATE
, LOCAL_TIME
);
380 * Print an unsigned relative number of seconds (e.g. hold time, prune timer)
381 * in the form 5m1s. This does no truncation, so 32230861 seconds
382 * is represented as 1y1w1d1h1m1s.
385 unsigned_relts_print(netdissect_options
*ndo
,
388 static const char *lengths
[] = {"y", "w", "d", "h", "m", "s"};
389 static const u_int seconds
[] = {31536000, 604800, 86400, 3600, 60, 1};
390 const char **l
= lengths
;
391 const u_int
*s
= seconds
;
399 ND_PRINT("%u%s", secs
/ *s
, *l
);
400 secs
-= (secs
/ *s
) * *s
;
408 * Print a signed relative number of seconds (e.g. hold time, prune timer)
409 * in the form 5m1s. This does no truncation, so 32230861 seconds
410 * is represented as 1y1w1d1h1m1s.
413 signed_relts_print(netdissect_options
*ndo
,
418 if (secs
== INT32_MIN
) {
420 * -2^31; you can't fit its absolute value into
421 * a 32-bit signed integer.
423 * Just directly pass said absolute value to
424 * unsigned_relts_print() directly.
426 * (XXX - does ISO C guarantee that -(-2^n),
427 * when calculated and cast to an n-bit unsigned
428 * integer type, will have the value 2^n?)
430 unsigned_relts_print(ndo
, 2147483648U);
433 * We now know -secs will fit into an int32_t;
434 * negate it and pass that to unsigned_relts_print().
436 unsigned_relts_print(ndo
, -secs
);
440 unsigned_relts_print(ndo
, secs
);
443 /* Print the truncated string */
444 void nd_print_trunc(netdissect_options
*ndo
)
446 ND_PRINT(" [|%s]", ndo
->ndo_protocol
);
449 /* Print the protocol name */
450 void nd_print_protocol(netdissect_options
*ndo
)
452 ND_PRINT("%s", ndo
->ndo_protocol
);
455 /* Print the protocol name in caps (uppercases) */
456 void nd_print_protocol_caps(netdissect_options
*ndo
)
459 for (p
= ndo
->ndo_protocol
; *p
!= '\0'; p
++)
460 ND_PRINT("%c", ND_ASCII_TOUPPER(*p
));
463 /* Print the invalid string */
464 void nd_print_invalid(netdissect_options
*ndo
)
466 ND_PRINT(" (invalid)");
470 * this is a generic routine for printing unknown data;
471 * we pass on the linefeed plus indentation string to
472 * get a proper output - returns 0 on error
476 print_unknown_data(netdissect_options
*ndo
, const u_char
*cp
,
477 const char *ident
, u_int len
)
482 if (!ND_TTEST_LEN(cp
, 0)) {
483 ND_PRINT("%sDissector error: print_unknown_data called with pointer past end of packet",
487 if (ND_BYTES_AVAILABLE_AFTER(cp
) < len_to_print
)
488 len_to_print
= ND_BYTES_AVAILABLE_AFTER(cp
);
489 hex_print(ndo
, ident
, cp
, len_to_print
);
490 return(1); /* everything is ok */
494 * Convert a token value to a string; use "fmt" if not found.
497 tok2strbuf(const struct tok
*lp
, const char *fmt
,
498 u_int v
, char *buf
, size_t bufsize
)
501 while (lp
->s
!= NULL
) {
510 (void)snprintf(buf
, bufsize
, fmt
, v
);
511 return (const char *)buf
;
515 * Convert a token value to a string; use "fmt" if not found.
516 * Uses tok2strbuf() on one of four local static buffers of size TOKBUFSIZE
517 * in round-robin fashion.
520 tok2str(const struct tok
*lp
, const char *fmt
,
523 static char buf
[4][TOKBUFSIZE
];
529 return tok2strbuf(lp
, fmt
, v
, ret
, sizeof(buf
[0]));
533 * Convert a bit token value to a string; use "fmt" if not found.
534 * this is useful for parsing bitfields, the output strings are separated
535 * if the s field is positive.
538 bittok2str_internal(const struct tok
*lp
, const char *fmt
,
539 u_int v
, const char *sep
)
541 static char buf
[1024+1]; /* our string buffer */
543 size_t space_left
= sizeof(buf
), string_size
;
544 u_int rotbit
; /* this is the bit we rotate through all bitpositions */
546 const char * sepstr
= "";
548 while (lp
!= NULL
&& lp
->s
!= NULL
) {
549 tokval
=lp
->v
; /* load our first value */
551 while (rotbit
!= 0) {
553 * lets AND the rotating bit with our token value
554 * and see if we have got a match
556 if (tokval
== (v
&rotbit
)) {
557 /* ok we have found something */
559 return (buf
); /* only enough room left for NUL, if that */
560 string_size
= strlcpy(bufp
, sepstr
, space_left
);
561 if (string_size
>= space_left
)
562 return (buf
); /* we ran out of room */
564 space_left
-= string_size
;
566 return (buf
); /* only enough room left for NUL, if that */
567 string_size
= strlcpy(bufp
, lp
->s
, space_left
);
568 if (string_size
>= space_left
)
569 return (buf
); /* we ran out of room */
571 space_left
-= string_size
;
575 rotbit
=rotbit
<<1; /* no match - lets shift and try again */
581 /* bummer - lets print the "unknown" message as advised in the fmt string if we got one */
582 (void)snprintf(buf
, sizeof(buf
), fmt
== NULL
? "#%08x" : fmt
, v
);
587 * Convert a bit token value to a string; use "fmt" if not found.
588 * this is useful for parsing bitfields, the output strings are not separated.
591 bittok2str_nosep(const struct tok
*lp
, const char *fmt
,
594 return (bittok2str_internal(lp
, fmt
, v
, ""));
598 * Convert a bit token value to a string; use "fmt" if not found.
599 * this is useful for parsing bitfields, the output strings are comma separated.
602 bittok2str(const struct tok
*lp
, const char *fmt
,
605 return (bittok2str_internal(lp
, fmt
, v
, ", "));
609 * Convert a value to a string using an array; the macro
610 * tok2strary() in <netdissect.h> is the public interface to
611 * this function and ensures that the second argument is
612 * correct for bounds-checking.
615 tok2strary_internal(const char **lp
, int n
, const char *fmt
,
618 static char buf
[TOKBUFSIZE
];
620 if (v
>= 0 && v
< n
&& lp
[v
] != NULL
)
624 (void)snprintf(buf
, sizeof(buf
), fmt
, v
);
629 * Convert a 32-bit netmask to prefixlen if possible
630 * the function returns the prefix-len; if plen == -1
631 * then conversion was not possible;
635 mask2plen(uint32_t mask
)
637 uint32_t bitmasks
[33] = {
639 0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
640 0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
641 0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
642 0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
643 0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
644 0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
645 0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
646 0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
650 /* let's see if we can transform the mask into a prefixlen */
651 while (prefix_len
>= 0) {
652 if (bitmasks
[prefix_len
] == mask
)
660 mask62plen(const u_char
*mask
)
662 u_char bitmasks
[9] = {
664 0x80, 0xc0, 0xe0, 0xf0,
665 0xf8, 0xfc, 0xfe, 0xff
670 for (byte
= 0; byte
< 16; byte
++) {
673 for (bits
= 0; bits
< (sizeof (bitmasks
) / sizeof (bitmasks
[0])); bits
++) {
674 if (mask
[byte
] == bitmasks
[bits
]) {
680 if (mask
[byte
] != 0xff)
687 * Routine to print out information for text-based protocols such as FTP,
688 * HTTP, SMTP, RTSP, SIP, ....
690 #define MAX_TOKEN 128
693 * Fetch a token from a packet, starting at the specified index,
694 * and return the length of the token.
696 * Returns 0 on error; yes, this is indistinguishable from an empty
697 * token, but an "empty token" isn't a valid token - it just means
698 * either a space character at the beginning of the line (this
699 * includes a blank line) or no more tokens remaining on the line.
702 fetch_token(netdissect_options
*ndo
, const u_char
*pptr
, u_int idx
, u_int len
,
703 u_char
*tbuf
, size_t tbuflen
)
708 for (; idx
< len
; idx
++) {
709 if (!ND_TTEST_1(pptr
+ idx
)) {
710 /* ran past end of captured data */
713 c
= GET_U_1(pptr
+ idx
);
714 if (!ND_ISASCII(c
)) {
715 /* not an ASCII character */
718 if (c
== ' ' || c
== '\t' || c
== '\r' || c
== '\n') {
722 if (!ND_ASCII_ISPRINT(c
)) {
723 /* not part of a command token or response code */
726 if (toklen
+ 2 > tbuflen
) {
727 /* no room for this character and terminating '\0' */
740 * Skip past any white space after the token, until we see
741 * an end-of-line (CR or LF).
743 for (; idx
< len
; idx
++) {
744 if (!ND_TTEST_1(pptr
+ idx
)) {
745 /* ran past end of captured data */
748 c
= GET_U_1(pptr
+ idx
);
749 if (c
== '\r' || c
== '\n') {
753 if (!ND_ASCII_ISPRINT(c
)) {
754 /* not a printable ASCII character */
757 if (c
!= ' ' && c
!= '\t' && c
!= '\r' && c
!= '\n') {
758 /* beginning of next token */
766 * Scan a buffer looking for a line ending - LF or CR-LF.
767 * Return the index of the character after the line ending or 0 if
768 * we encounter a non-ASCII or non-printable character or don't find
772 print_txt_line(netdissect_options
*ndo
, const char *prefix
,
773 const u_char
*pptr
, u_int idx
, u_int len
)
781 c
= GET_U_1(pptr
+ idx
);
784 * LF without CR; end of line.
785 * Skip the LF and print the line, with the
786 * exception of the LF.
788 linelen
= idx
- startidx
;
791 } else if (c
== '\r') {
793 if ((idx
+1) >= len
) {
794 /* not in this packet */
797 if (GET_U_1(pptr
+ idx
+ 1) == '\n') {
799 * CR-LF; end of line.
800 * Skip the CR-LF and print the line, with
801 * the exception of the CR-LF.
803 linelen
= idx
- startidx
;
809 * CR followed by something else; treat this
810 * as if it were binary data, and don't print
814 } else if (!ND_ASCII_ISPRINT(c
) && c
!= '\t') {
816 * Not a printable ASCII character and not a tab;
817 * treat this as if it were binary data, and
826 * All printable ASCII, but no line ending after that point
827 * in the buffer; treat this as if it were truncated.
829 linelen
= idx
- startidx
;
830 ND_PRINT("%s%.*s", prefix
, (int)linelen
, pptr
+ startidx
);
835 ND_PRINT("%s%.*s", prefix
, (int)linelen
, pptr
+ startidx
);
839 /* Assign needed before calling txtproto_print(): ndo->ndo_protocol = "proto" */
841 txtproto_print(netdissect_options
*ndo
, const u_char
*pptr
, u_int len
,
842 const char **cmds
, u_int flags
)
845 u_char token
[MAX_TOKEN
+1];
851 * This protocol has more than just request and
852 * response lines; see whether this looks like a
853 * request or response and, if so, print it and,
854 * in verbose mode, print everything after it.
856 * This is for HTTP-like protocols, where we
857 * want to print requests and responses, but
858 * don't want to print continuations of request
859 * or response bodies in packets that don't
860 * contain the request or response line.
862 idx
= fetch_token(ndo
, pptr
, 0, len
, token
, sizeof(token
));
864 /* Is this a valid request name? */
865 while ((cmd
= *cmds
++) != NULL
) {
866 if (ascii_strcasecmp((const char *)token
, cmd
) == 0) {
874 * No - is this a valid response code (3 digits)?
876 * Is this token the response code, or is the next
877 * token the response code?
879 if (flags
& RESP_CODE_SECOND_TOKEN
) {
881 * Next token - get it.
883 idx
= fetch_token(ndo
, pptr
, idx
, len
, token
,
887 if (ND_ASCII_ISDIGIT(token
[0]) && ND_ASCII_ISDIGIT(token
[1]) &&
888 ND_ASCII_ISDIGIT(token
[2]) && token
[3] == '\0') {
898 * 1) This protocol has only request and response lines
899 * (e.g., FTP, where all the data goes over a different
900 * connection); assume the payload is a request or
905 * 2) This protocol is just text, so that we should
906 * always, at minimum, print the first line and,
907 * in verbose mode, print all lines.
912 nd_print_protocol_caps(ndo
);
916 * In non-verbose mode, just print the protocol, followed
919 * In verbose mode, print lines as text until we run out
920 * of characters or see something that's not a
921 * printable-ASCII line.
923 if (ndo
->ndo_vflag
) {
925 * We're going to print all the text lines in the
926 * request or response; just print the length
927 * on the first line of the output.
929 ND_PRINT(", length: %u", len
);
931 idx
< len
&& (eol
= print_txt_line(ndo
, "\n\t", pptr
, idx
, len
)) != 0;
936 * Just print the first text line.
938 print_txt_line(ndo
, ": ", pptr
, 0, len
);
943 #if (defined(__i386__) || defined(_M_IX86) || defined(__X86__) || defined(__x86_64__) || defined(_M_X64)) || \
944 (defined(__arm__) || defined(_M_ARM) || defined(__aarch64__)) || \
945 (defined(__m68k__) && (!defined(__mc68000__) && !defined(__mc68010__))) || \
946 (defined(__ppc__) || defined(__ppc64__) || defined(_M_PPC) || defined(_ARCH_PPC) || defined(_ARCH_PPC64)) || \
947 (defined(__s390__) || defined(__s390x__) || defined(__zarch__)) || \
950 * The procesor natively handles unaligned loads, so just use memcpy()
951 * and memcmp(), to enable those optimizations.
953 * XXX - are those all the x86 tests we need?
954 * XXX - do we need to worry about ARMv1 through ARMv5, which didn't
955 * support unaligned loads, and, if so, do we need to worry about all
956 * of them, or just some of them, e.g. ARMv5?
957 * XXX - are those the only 68k tests we need not to generated
958 * unaligned accesses if the target is the 68000 or 68010?
959 * XXX - are there any tests we don't need, because some definitions are for
960 * compilers that also predefine the GCC symbols?
961 * XXX - do we need to test for both 32-bit and 64-bit versions of those
962 * architectures in all cases?
966 * The processor doesn't natively handle unaligned loads,
967 * and the compiler might "helpfully" optimize memcpy()
968 * and memcmp(), when handed pointers that would normally
969 * be properly aligned, into sequences that assume proper
972 * Do copies and compares of possibly-unaligned data by
973 * calling routines that wrap memcpy() and memcmp(), to
974 * prevent that optimization.
977 unaligned_memcpy(void *p
, const void *q
, size_t l
)
982 /* As with memcpy(), so with memcmp(). */
984 unaligned_memcmp(const void *p
, const void *q
, size_t l
)
986 return (memcmp(p
, q
, l
));