diff options
Diffstat (limited to 'resolv/res_comp.c')
| -rw-r--r-- | resolv/res_comp.c | 924 |
1 files changed, 683 insertions, 241 deletions
diff --git a/resolv/res_comp.c b/resolv/res_comp.c index 94a6270b6e..2661963632 100644 --- a/resolv/res_comp.c +++ b/resolv/res_comp.c @@ -63,9 +63,10 @@ static char rcsid[] = "$Id$"; #include <netinet/in.h> #include <arpa/nameser.h> -#include <stdio.h> -#include <resolv.h> #include <ctype.h> +#include <errno.h> +#include <resolv.h> +#include <stdio.h> #if defined(BSD) && (BSD >= 199103) # include <unistd.h> @@ -74,8 +75,17 @@ static char rcsid[] = "$Id$"; # include "../conf/portability.h" #endif -static int dn_find __P((u_char *exp_dn, u_char *msg, - u_char **dnptrs, u_char **lastdnptr)); +static int ns_name_ntop __P((const u_char *, char *, size_t)); +static int ns_name_pton __P((const char *, u_char *, size_t)); +static int ns_name_unpack __P((const u_char *, const u_char *, + const u_char *, u_char *, size_t)); +static int ns_name_pack __P((const u_char *, u_char *, int, + const u_char **, const u_char **)); +static int ns_name_uncompress __P((const u_char *, const u_char *, + const u_char *, char *, size_t)); +static int ns_name_compress __P((const char *, u_char *, size_t, + const u_char **, const u_char **)); +static int ns_name_skip __P((const u_char **, const u_char *)); /* * Expand compressed domain name 'comp_dn' to full domain name. @@ -85,261 +95,51 @@ static int dn_find __P((u_char *exp_dn, u_char *msg, * Return size of compressed name or -1 if there was an error. */ int -dn_expand(msg, eomorig, comp_dn, exp_dn, length) - const u_char *msg, *eomorig, *comp_dn; - char *exp_dn; - int length; +dn_expand(msg, eom, src, dst, dstsiz) + const u_char *msg; + const u_char *eom; + const u_char *src; + char *dst; + int dstsiz; { - register const u_char *cp; - register char *dn; - register int n, c; - char *eom; - int len = -1, checked = 0, octets = 0; - - dn = exp_dn; - cp = comp_dn; - eom = exp_dn + length; - /* - * fetch next label in domain name - */ - while (n = *cp++) { - /* - * Check for indirection - */ - switch (n & INDIR_MASK) { - case 0: - octets += (n + 1); - if (octets > MAXCDNAME) - return (-1); - if (dn != exp_dn) { - if (dn >= eom) - return (-1); - *dn++ = '.'; - } - if (dn+n >= eom) - return (-1); - checked += n + 1; - while (--n >= 0) { - if (((c = *cp++) == '.') || (c == '\\')) { - if (dn + n + 2 >= eom) - return (-1); - *dn++ = '\\'; - } - *dn++ = c; - if (cp >= eomorig) /* out of range */ - return (-1); - } - break; + int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz); - case INDIR_MASK: - if (len < 0) - len = cp - comp_dn + 1; - cp = msg + (((n & 0x3f) << 8) | (*cp & 0xff)); - if (cp < msg || cp >= eomorig) /* out of range */ - return (-1); - checked += 2; - /* - * Check for loops in the compressed name; - * if we've looked at the whole message, - * there must be a loop. - */ - if (checked >= eomorig - msg) - return (-1); - break; - - default: - return (-1); /* flag error */ - } - } - *dn = '\0'; - if (len < 0) - len = cp - comp_dn; - return (len); + if (n > 0 && dst[0] == '.') + dst[0] = '\0'; + return (n); } /* - * Compress domain name 'exp_dn' into 'comp_dn'. + * Pack domain name 'exp_dn' in presentation form into 'comp_dn'. * Return the size of the compressed name or -1. * 'length' is the size of the array pointed to by 'comp_dn'. - * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0] - * is a pointer to the beginning of the message. The list ends with NULL. - * 'lastdnptr' is a pointer to the end of the array pointed to - * by 'dnptrs'. Side effect is to update the list of pointers for - * labels inserted into the message as we compress the name. - * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' - * is NULL, we don't update the list. */ int -dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr) - const char *exp_dn; - u_char *comp_dn, **dnptrs, **lastdnptr; - int length; +dn_comp(src, dst, dstsiz, dnptrs, lastdnptr) + const char *src; + u_char *dst; + int dstsiz; + u_char **dnptrs; + u_char **lastdnptr; { - register u_char *cp, *dn; - register int c, l; - u_char **cpp, **lpp, *sp, *eob; - u_char *msg; - - dn = (u_char *)exp_dn; - cp = comp_dn; - if (length > MAXCDNAME) - length = MAXCDNAME; - eob = cp + length; - lpp = cpp = NULL; - if (dnptrs != NULL) { - if ((msg = *dnptrs++) != NULL) { - for (cpp = dnptrs; *cpp != NULL; cpp++) - ; - lpp = cpp; /* end of list to search */ - } - } else - msg = NULL; - for (c = *dn++; c != '\0'; ) { - /* look to see if we can use pointers */ - if (msg != NULL) { - if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) { - if (cp+1 >= eob) - return (-1); - *cp++ = (l >> 8) | INDIR_MASK; - *cp++ = l % 256; - return (cp - comp_dn); - } - /* not found, save it */ - if (lastdnptr != NULL && cpp < lastdnptr-1) { - *cpp++ = cp; - *cpp = NULL; - } - } - sp = cp++; /* save ptr to length byte */ - do { - if (c == '.') { - c = *dn++; - break; - } - if (c == '\\') { - if ((c = *dn++) == '\0') - break; - } - if (cp >= eob) { - if (msg != NULL) - *lpp = NULL; - return (-1); - } - *cp++ = c; - } while ((c = *dn++) != '\0'); - /* catch trailing '.'s but not '..' */ - if ((l = cp - sp - 1) == 0 && c == '\0') { - cp--; - break; - } - if (l <= 0 || l > MAXLABEL) { - if (msg != NULL) - *lpp = NULL; - return (-1); - } - *sp = l; - } - if (cp >= eob) { - if (msg != NULL) - *lpp = NULL; - return (-1); - } - *cp++ = '\0'; - return (cp - comp_dn); + return (ns_name_compress(src, dst, (size_t)dstsiz, + (const u_char **)dnptrs, + (const u_char **)lastdnptr)); } /* * Skip over a compressed domain name. Return the size or -1. */ int -__dn_skipname(comp_dn, eom) - const u_char *comp_dn, *eom; +__dn_skipname(ptr, eom) + const u_char *ptr; + const u_char *eom; { - register const u_char *cp; - register int n; - - cp = comp_dn; - while (cp < eom && (n = *cp++)) { - /* - * check for indirection - */ - switch (n & INDIR_MASK) { - case 0: /* normal case, n == len */ - cp += n; - continue; - case INDIR_MASK: /* indirection */ - cp++; - break; - default: /* illegal type */ - return (-1); - } - break; - } - if (cp > eom) - return (-1); - return (cp - comp_dn); -} - -static int -mklower(ch) - register int ch; -{ - if (isascii(ch) && isupper(ch)) - return (tolower(ch)); - return (ch); -} - -/* - * Search for expanded name from a list of previously compressed names. - * Return the offset from msg if found or -1. - * dnptrs is the pointer to the first name on the list, - * not the pointer to the start of the message. - */ -static int -dn_find(exp_dn, msg, dnptrs, lastdnptr) - u_char *exp_dn, *msg; - u_char **dnptrs, **lastdnptr; -{ - register u_char *dn, *cp, **cpp; - register int n; - u_char *sp; + const u_char *saveptr = ptr; - for (cpp = dnptrs; cpp < lastdnptr; cpp++) { - dn = exp_dn; - sp = cp = *cpp; - while (n = *cp++) { - /* - * check for indirection - */ - switch (n & INDIR_MASK) { - case 0: /* normal case, n == len */ - while (--n >= 0) { - if (*dn == '.') - goto next; - if (*dn == '\\') - dn++; - if (mklower(*dn++) != mklower(*cp++)) - goto next; - } - if ((n = *dn++) == '\0' && *cp == '\0') - return (sp - msg); - if (n == '.') - continue; - goto next; - - case INDIR_MASK: /* indirection */ - cp = msg + (((n & 0x3f) << 8) | *cp); - break; - - default: /* illegal type */ - return (-1); - } - } - if (*dn == '\0') - return (sp - msg); - next: ; - } - return (-1); + if (ns_name_skip(&ptr, eom) == -1) + return (-1); + return (ptr - saveptr); } /* @@ -510,3 +310,645 @@ __putlong(l, msgp) { PUTLONG(l, msgp); } + +/* ++ From BIND 8.1.1. ++ */ +/* + * Copyright (c) 1996 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS + * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE + * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + */ + +/*"Id: ns_name.c,v 1.1 1997/12/13 02:41:13 vixie Exp vixie"*/ + +/*#include "port_before.h"*/ + +/*#include <sys/types.h>*/ + +/*#include <netinet/in.h>*/ +/*#include <arpa/nameser.h>*/ + +/*#include <errno.h>*/ +/*#include <resolv.h>*/ +/*#include <string.h>*/ + +/*#include "port_after.h"*/ + +#define NS_CMPRSFLGS 0xc0 /* Flag bits indicating name compression. */ +#define NS_MAXCDNAME 255 /* maximum compressed domain name */ + +/* Data. */ + +static char digits[] = "0123456789"; + +/* Forward. */ + +static int special(int); +static int printable(int); +static int dn_find(const u_char *, const u_char *, + const u_char * const *, + const u_char * const *); + +/* Public. */ + +/* + * ns_name_ntop(src, dst, dstsiz) + * Convert an encoded domain name to printable ascii as per RFC1035. + * return: + * Number of bytes written to buffer, or -1 (with errno set) + * notes: + * The root is returned as "." + * All other domains are returned in non absolute form + */ +static int +ns_name_ntop(src, dst, dstsiz) + const u_char *src; + char *dst; + size_t dstsiz; +{ + const u_char *cp; + char *dn, *eom; + u_char c; + u_int n; + + cp = src; + dn = dst; + eom = dst + dstsiz; + + while ((n = *cp++) != 0) { + if ((n & NS_CMPRSFLGS) != 0) { + /* Some kind of compression pointer. */ + __set_errno (EMSGSIZE); + return (-1); + } + if (dn != dst) { + if (dn >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = '.'; + } + if (dn + n >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + for ((void)NULL; n > 0; n--) { + c = *cp++; + if (special(c)) { + if (dn + 1 >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = '\\'; + *dn++ = (char)c; + } else if (!printable(c)) { + if (dn + 3 >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = '\\'; + *dn++ = digits[c / 100]; + *dn++ = digits[(c % 100) / 10]; + *dn++ = digits[c % 10]; + } else { + if (dn >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = (char)c; + } + } + } + if (dn == dst) { + if (dn >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = '.'; + } + if (dn >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *dn++ = '\0'; + return (dn - dst); +} + +/* + * ns_name_pton(src, dst, dstsiz) + * Convert a ascii string into an encoded domain name as per RFC1035. + * return: + * -1 if it fails + * 1 if string was fully qualified + * 0 is string was not fully qualified + * notes: + * Enforces label and domain length limits. + */ + +static int +ns_name_pton(src, dst, dstsiz) + const char *src; + u_char *dst; + size_t dstsiz; +{ + u_char *label, *bp, *eom; + int c, n, escaped; + char *cp; + + escaped = 0; + bp = dst; + eom = dst + dstsiz; + label = bp++; + + while ((c = *src++) != 0) { + if (escaped) { + if ((cp = strchr(digits, c)) != NULL) { + n = (cp - digits) * 100; + if ((c = *src++) == 0 || + (cp = strchr(digits, c)) == NULL) { + __set_errno (EMSGSIZE); + return (-1); + } + n += (cp - digits) * 10; + if ((c = *src++) == 0 || + (cp = strchr(digits, c)) == NULL) { + __set_errno (EMSGSIZE); + return (-1); + } + n += (cp - digits); + if (n > 255) { + __set_errno (EMSGSIZE); + return (-1); + } + c = n; + } + escaped = 0; + } else if (c == '\\') { + escaped = 1; + continue; + } else if (c == '.') { + c = (bp - label - 1); + if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */ + __set_errno (EMSGSIZE); + return (-1); + } + if (label >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *label = c; + /* Fully qualified ? */ + if (*src == '\0') { + if (c != 0) { + if (bp >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *bp++ = '\0'; + } + if ((bp - dst) > MAXCDNAME) { + __set_errno (EMSGSIZE); + return (-1); + } + return (1); + } + if (c == 0) { + __set_errno (EMSGSIZE); + return (-1); + } + label = bp++; + continue; + } + if (bp >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *bp++ = (u_char)c; + } + c = (bp - label - 1); + if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */ + __set_errno (EMSGSIZE); + return (-1); + } + if (label >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *label = c; + if (c != 0) { + if (bp >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *bp++ = 0; + } + if ((bp - dst) > MAXCDNAME) { /* src too big */ + __set_errno (EMSGSIZE); + return (-1); + } + return (0); +} + +/* + * ns_name_unpack(msg, eom, src, dst, dstsiz) + * Unpack a domain name from a message, source may be compressed. + * return: + * -1 if it fails, or consumed octets if it succeeds. + */ +static int +ns_name_unpack(msg, eom, src, dst, dstsiz) + const u_char *msg; + const u_char *eom; + const u_char *src; + u_char *dst; + size_t dstsiz; +{ + const u_char *srcp, *dstlim; + u_char *dstp; +#ifdef _LIBC + /* We don't want warnings! */ + int n, len, checked; +#else + int n, c, len, checked; +#endif + + len = -1; + checked = 0; + dstp = dst; + srcp = src; + dstlim = dst + dstsiz; + if (srcp < msg || srcp >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + /* Fetch next label in domain name. */ + while ((n = *srcp++) != 0) { + /* Check for indirection. */ + switch (n & NS_CMPRSFLGS) { + case 0: + /* Limit checks. */ + if (dstp + n + 1 >= dstlim || srcp + n >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + checked += n + 1; + *dstp++ = n; + memcpy(dstp, srcp, n); + dstp += n; + srcp += n; + break; + + case NS_CMPRSFLGS: + if (srcp >= eom) { + __set_errno (EMSGSIZE); + return (-1); + } + if (len < 0) + len = srcp - src + 1; + srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff)); + if (srcp < msg || srcp >= eom) { /* Out of range. */ + __set_errno (EMSGSIZE); + return (-1); + } + checked += 2; + /* + * Check for loops in the compressed name; + * if we've looked at the whole message, + * there must be a loop. + */ + if (checked >= eom - msg) { + __set_errno (EMSGSIZE); + return (-1); + } + break; + + default: + __set_errno (EMSGSIZE); + return (-1); /* flag error */ + } + } + *dstp = '\0'; + if (len < 0) + len = srcp - src; + return (len); +} + +/* + * ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr) + * Pack domain name 'domain' into 'comp_dn'. + * return: + * Size of the compressed name, or -1. + * notes: + * 'dnptrs' is an array of pointers to previous compressed names. + * dnptrs[0] is a pointer to the beginning of the message. The array + * ends with NULL. + * 'lastdnptr' is a pointer to the end of the array pointed to + * by 'dnptrs'. + * Side effects: + * The list of pointers in dnptrs is updated for labels inserted into + * the message as we compress the name. If 'dnptr' is NULL, we don't + * try to compress names. If 'lastdnptr' is NULL, we don't update the + * list. + */ +static int +ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr) + const u_char *src; + u_char *dst; + int dstsiz; + const u_char **dnptrs; + const u_char **lastdnptr; +{ + u_char *dstp; + const u_char **cpp, **lpp, *eob, *msg; + const u_char *srcp; + int n, l; + + srcp = src; + dstp = dst; + eob = dstp + dstsiz; + lpp = cpp = NULL; + if (dnptrs != NULL) { + if ((msg = *dnptrs++) != NULL) { + for (cpp = dnptrs; *cpp != NULL; cpp++) + (void)NULL; + lpp = cpp; /* end of list to search */ + } + } else + msg = NULL; + + /* make sure the domain we are about to add is legal */ + l = 0; + do { + n = *srcp; + if ((n & NS_CMPRSFLGS) != 0) { + __set_errno (EMSGSIZE); + return (-1); + } + l += n + 1; + if (l > MAXCDNAME) { + __set_errno (EMSGSIZE); + return (-1); + } + srcp += n + 1; + } while (n != 0); + + srcp = src; + do { + /* Look to see if we can use pointers. */ + n = *srcp; + if (n != 0 && msg != NULL) { + l = dn_find(srcp, msg, (const u_char * const *)dnptrs, + (const u_char * const *)lpp); + if (l >= 0) { + if (dstp + 1 >= eob) { + __set_errno (EMSGSIZE); + return (-1); + } + *dstp++ = (l >> 8) | NS_CMPRSFLGS; + *dstp++ = l % 256; + return (dstp - dst); + } + /* Not found, save it. */ + if (lastdnptr != NULL && cpp < lastdnptr - 1 && + (dstp - msg) < 0x4000) { + *cpp++ = dstp; + *cpp = NULL; + } + } + /* copy label to buffer */ + if (n & NS_CMPRSFLGS) { /* Should not happen. */ + __set_errno (EMSGSIZE); + return (-1); + } + if (dstp + 1 + n >= eob) { + __set_errno (EMSGSIZE); + return (-1); + } + memcpy(dstp, srcp, n + 1); + srcp += n + 1; + dstp += n + 1; + } while (n != 0); + + if (dstp > eob) { + if (msg != NULL) + *lpp = NULL; + __set_errno (EMSGSIZE); + return (-1); + } + return (dstp - dst); +} + +/* + * ns_name_uncompress(msg, eom, src, dst, dstsiz) + * Expand compressed domain name to presentation format. + * return: + * Number of bytes read out of `src', or -1 (with errno set). + * note: + * Root domain returns as "." not "". + */ +static int +ns_name_uncompress(msg, eom, src, dst, dstsiz) + const u_char *msg; + const u_char *eom; + const u_char *src; + char *dst; + size_t dstsiz; +{ + u_char tmp[NS_MAXCDNAME]; + int n; + + if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1) + return (-1); + if (ns_name_ntop(tmp, dst, dstsiz) == -1) + return (-1); + return (n); +} + +/* + * ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr) + * Compress a domain name into wire format, using compression pointers. + * return: + * Number of bytes consumed in `dst' or -1 (with errno set). + * notes: + * 'dnptrs' is an array of pointers to previous compressed names. + * dnptrs[0] is a pointer to the beginning of the message. + * The list ends with NULL. 'lastdnptr' is a pointer to the end of the + * array pointed to by 'dnptrs'. Side effect is to update the list of + * pointers for labels inserted into the message as we compress the name. + * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' + * is NULL, we don't update the list. + */ +static int +ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr) + const char *src; + u_char *dst; + size_t dstsiz; + const u_char **dnptrs; + const u_char **lastdnptr; +{ + u_char tmp[NS_MAXCDNAME]; + + if (ns_name_pton(src, tmp, sizeof tmp) == -1) + return (-1); + return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr)); +} + +/* + * ns_name_skip(ptrptr, eom) + * Advance *ptrptr to skip over the compressed name it points at. + * return: + * 0 on success, -1 (with errno set) on failure. + */ +static int +ns_name_skip(ptrptr, eom) + const u_char **ptrptr; + const u_char *eom; +{ + const u_char *cp; + u_int n; + + cp = *ptrptr; + while (cp < eom && (n = *cp++) != 0) { + /* Check for indirection. */ + switch (n & NS_CMPRSFLGS) { + case 0: /* normal case, n == len */ + cp += n; + continue; + case NS_CMPRSFLGS: /* indirection */ + cp++; + break; + default: /* illegal type */ + __set_errno (EMSGSIZE); + return (-1); + } + break; + } + if (cp > eom) { + __set_errno (EMSGSIZE); + return (-1); + } + *ptrptr = cp; + return (0); +} + +/* Private. */ + +/* + * special(ch) + * Thinking in noninternationalized USASCII (per the DNS spec), + * is this characted special ("in need of quoting") ? + * return: + * boolean. + */ +static int +special(ch) + int ch; +{ + switch (ch) { + case 0x22: /* '"' */ + case 0x2E: /* '.' */ + case 0x3B: /* ';' */ + case 0x5C: /* '\\' */ + /* Special modifiers in zone files. */ + case 0x40: /* '@' */ + case 0x24: /* '$' */ + return (1); + default: + return (0); + } +} + +/* + * printable(ch) + * Thinking in noninternationalized USASCII (per the DNS spec), + * is this character visible and not a space when printed ? + * return: + * boolean. + */ +static int +printable(ch) + int ch; +{ + return (ch > 0x20 && ch < 0x7f); +} + +/* + * Thinking in noninternationalized USASCII (per the DNS spec), + * convert this character to lower case if it's upper case. + */ +static int +mklower(ch) + int ch; +{ + if (ch >= 0x41 && ch <= 0x5A) + return (ch + 0x20); + return (ch); +} + +/* + * dn_find(domain, msg, dnptrs, lastdnptr) + * Search for the counted-label name in an array of compressed names. + * return: + * offset from msg if found, or -1. + * notes: + * dnptrs is the pointer to the first name on the list, + * not the pointer to the start of the message. + */ +static int +dn_find(domain, msg, dnptrs, lastdnptr) + const u_char *domain; + const u_char *msg; + const u_char * const *dnptrs; + const u_char * const *lastdnptr; +{ + const u_char *dn, *cp, *sp; + const u_char * const *cpp; + u_int n; + + for (cpp = dnptrs; cpp < lastdnptr; cpp++) { + dn = domain; + sp = cp = *cpp; + while ((n = *cp++) != 0) { + /* + * check for indirection + */ + switch (n & NS_CMPRSFLGS) { + case 0: /* normal case, n == len */ + if (n != *dn++) + goto next; + for ((void)NULL; n > 0; n--) + if (mklower(*dn++) != mklower(*cp++)) + goto next; + /* Is next root for both ? */ + if (*dn == '\0' && *cp == '\0') + return (sp - msg); + if (*dn) + continue; + goto next; + + case NS_CMPRSFLGS: /* indirection */ + cp = msg + (((n & 0x3f) << 8) | *cp); + break; + + default: /* illegal type */ + __set_errno (EMSGSIZE); + return (-1); + } + } + next: ; + } + __set_errno (ENOENT); + return (-1); +} + +/* -- From BIND 8.1.1. -- */ |