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7ed1ac6da3
And reformat to GNU style, and eliminate the labellen function. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
203 lines
5.8 KiB
C
203 lines
5.8 KiB
C
/* Compression of DNS domain names.
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996,1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <arpa/nameser.h>
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#include <errno.h>
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#include <string.h>
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#include <shlib-compat.h>
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/* Thinking in noninternationalized USASCII (per the DNS spec),
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convert this character to lower case if it's upper case. */
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static int
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mklower (int ch)
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{
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if (ch >= 'A' && ch <= 'Z')
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return ch - 'A' + 'a';
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return ch;
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}
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/* Search for the counted-label name in an array of compressed names.
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Returns the offset from MSG if found, or -1.
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DNPTRS is the pointer to the first name on the list, not the
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pointer to the start of the message. */
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static int
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dn_find (const unsigned char *domain, const unsigned char *msg,
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const unsigned char **dnptrs,
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const unsigned char **lastdnptr)
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{
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const unsigned char *dn, *cp, *sp;
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const unsigned char **cpp;
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unsigned int n;
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for (cpp = dnptrs; cpp < lastdnptr; cpp++)
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{
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sp = *cpp;
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/* Terminate search on: root label, compression pointer, unusable
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offset. */
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while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 && (sp - msg) < 0x4000)
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{
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dn = domain;
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cp = sp;
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while ((n = *cp++) != 0)
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{
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/* Check for indirection. */
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switch (n & NS_CMPRSFLGS)
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{
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case 0: /* Normal case, n == len. */
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if (n != *dn++)
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goto next;
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for (; n > 0; n--)
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if (mklower (*dn++) != mklower (*cp++))
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goto next;
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/* Is next root for both? */
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if (*dn == '\0' && *cp == '\0')
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return sp - msg;
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if (*dn)
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continue;
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goto next;
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case NS_CMPRSFLGS: /* Indirection. */
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cp = msg + (((n & 0x3f) << 8) | *cp);
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break;
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default: /* Illegal type. */
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__set_errno (EMSGSIZE);
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return -1;
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}
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}
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next: ;
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sp += *sp + 1;
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}
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}
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__set_errno (ENOENT);
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return -1;
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}
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/* Packs domain name SRC into DST. Returns size of the compressed
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name, or -1.
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DNPTRS is an array of pointers to previous compressed names.
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DNPTRS[0] is a pointer to the beginning of the message. The array
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ends with NULL. LASTDNPTR is a pointer to the end of the array
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pointed to by 'dnptrs'.
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The list of pointers in DNPTRS is updated for labels inserted into
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the message as we compress the name. If DNPTRS is NULL, we don't
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try to compress names. If LASTDNPTR is NULL, we don't update the
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list. */
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int
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___ns_name_pack (const unsigned char *src, unsigned char *dst, int dstsiz,
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const unsigned char **dnptrs, const unsigned char **lastdnptr)
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{
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unsigned char *dstp;
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const unsigned char **cpp, **lpp, *eob, *msg;
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const unsigned char *srcp;
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int n, l, first = 1;
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srcp = src;
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dstp = dst;
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eob = dstp + dstsiz;
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lpp = cpp = NULL;
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if (dnptrs != NULL)
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{
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if ((msg = *dnptrs++) != NULL)
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{
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for (cpp = dnptrs; *cpp != NULL; cpp++)
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;
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lpp = cpp; /* End of list to search. */
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}
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}
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else
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msg = NULL;
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/* Make sure the domain we are about to add is legal. */
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l = 0;
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do
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{
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n = *srcp;
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if (n >= 64)
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{
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__set_errno (EMSGSIZE);
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return -1;
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}
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l += n + 1;
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if (l > MAXCDNAME)
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{
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__set_errno (EMSGSIZE);
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return -1;
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}
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srcp += n + 1;
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}
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while (n != 0);
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/* from here on we need to reset compression pointer array on error */
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srcp = src;
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do
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{
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/* Look to see if we can use pointers. */
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n = *srcp;
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if (n != 0 && msg != NULL)
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{
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l = dn_find (srcp, msg, dnptrs, lpp);
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if (l >= 0)
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{
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if (eob - dstp <= 1)
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goto cleanup;
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*dstp++ = (l >> 8) | NS_CMPRSFLGS;
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*dstp++ = l % 256;
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return dstp - dst;
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}
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/* Not found, save it. */
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if (lastdnptr != NULL && cpp < lastdnptr - 1
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&& (dstp - msg) < 0x4000 && first)
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{
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*cpp++ = dstp;
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*cpp = NULL;
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first = 0;
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}
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}
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/* Copy label to buffer. */
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if (n >= 64)
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/* Should not happen. */
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goto cleanup;
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if (n + 1 > eob - dstp)
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goto cleanup;
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memcpy (dstp, srcp, n + 1);
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srcp += n + 1;
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dstp += n + 1;
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}
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while (n != 0);
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if (dstp > eob)
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{
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cleanup:
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if (msg != NULL)
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*lpp = NULL;
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__set_errno (EMSGSIZE);
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return -1;
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}
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return dstp - dst;
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}
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versioned_symbol (libc, ___ns_name_pack, ns_name_pack, GLIBC_2_34);
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versioned_symbol (libc, ___ns_name_pack, __ns_name_pack, GLIBC_PRIVATE);
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libc_hidden_ver (___ns_name_pack, __ns_name_pack)
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#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_9, GLIBC_2_34)
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compat_symbol (libresolv, ___ns_name_pack, ns_name_pack, GLIBC_2_9);
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#endif
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