| /* |
| * Copyright (c) 1996,1999 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. |
| */ |
| |
| #include "config.h" |
| |
| #ifdef HAVE_RESOLV |
| |
| #include <sys/types.h> |
| |
| #ifdef HAVE_NETINET_IN_H |
| # include <netinet/in.h> |
| #endif |
| #ifdef HAVE_ARPA_NAMESER_H |
| # include <arpa/nameser.h> |
| #endif |
| |
| #include <ctype.h> |
| #include <errno.h> |
| #ifdef HAVE_RESOLV_H |
| # include <resolv.h> |
| #endif |
| #include <string.h> |
| |
| /* Data. */ |
| |
| static const char digits[] = "0123456789"; |
| |
| /* Private. */ |
| |
| /* |
| * special(ch) |
| * Thinking in noninternationalized USASCII (per the DNS spec), |
| * is this character special ("in need of quoting") ? |
| * return: |
| * boolean. |
| */ |
| static int |
| special(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(int ch) { |
| return (ch > 0x20 && ch < 0x7f); |
| } |
| |
| /* Public. */ |
| |
| /* |
| * dns_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 |
| dns_ns_name_ntop(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 && n != 0x41) { |
| /* Some kind of compression pointer. */ |
| return (-1); |
| } |
| if (dn != dst) { |
| if (dn >= eom) { |
| return (-1); |
| } |
| *dn++ = '.'; |
| } |
| |
| if (n == 0x41) { |
| n = *cp++ / 8; |
| if (dn + n * 2 + 4 >= eom) { |
| return (-1); |
| } |
| *dn++ = '\\'; |
| *dn++ = '['; |
| *dn++ = 'x'; |
| |
| while (n-- > 0) { |
| unsigned u; |
| c = *cp++; |
| u = c >> 4; |
| *dn++ = u > 9 ? 'a' + u - 10 : '0' + u; |
| u = c & 0xf; |
| *dn++ = u > 9 ? 'a' + u - 10 : '0' + u; |
| } |
| |
| *dn++ = ']'; |
| continue; |
| } |
| |
| if (dn + n >= eom) { |
| return (-1); |
| } |
| while (n-- > 0) { |
| c = *cp++; |
| if (special(c)) { |
| if (dn + 1 >= eom) { |
| return (-1); |
| } |
| *dn++ = '\\'; |
| *dn++ = (char)c; |
| } else if (!printable(c)) { |
| if (dn + 3 >= eom) { |
| return (-1); |
| } |
| *dn++ = '\\'; |
| *dn++ = digits[c / 100]; |
| *dn++ = digits[(c % 100) / 10]; |
| *dn++ = digits[c % 10]; |
| } else { |
| if (dn >= eom) { |
| return (-1); |
| } |
| *dn++ = (char)c; |
| } |
| } |
| } |
| if (dn == dst) { |
| if (dn >= eom) { |
| return (-1); |
| } |
| *dn++ = '.'; |
| } |
| if (dn >= eom) { |
| return (-1); |
| } |
| *dn++ = '\0'; |
| return (dn - dst); |
| } |
| |
| |
| /* |
| * dns_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 |
| dns_ns_name_unpack(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; |
| int n, len, checked; |
| |
| len = -1; |
| checked = 0; |
| dstp = dst; |
| srcp = src; |
| dstlim = dst + dstsiz; |
| if (srcp < msg || srcp >= eom) { |
| return (-1); |
| } |
| /* Fetch next label in domain name. */ |
| while ((n = *srcp++) != 0) { |
| /* Check for indirection. */ |
| switch (n & NS_CMPRSFLGS) { |
| case 0x40: |
| if (n == 0x41) { |
| if (dstp + 1 >= dstlim) { |
| return (-1); |
| } |
| *dstp++ = 0x41; |
| n = *srcp++ / 8; |
| ++checked; |
| } else { |
| return (-1); /* flag error */ |
| } |
| /* FALLTHROUGH */ |
| case 0: |
| /* Limit checks. */ |
| if (dstp + n + 1 >= dstlim || srcp + n >= eom) { |
| return (-1); |
| } |
| checked += n + 1; |
| dstp = memcpy(dstp, srcp - 1, n + 1); |
| dstp += n + 1; |
| srcp += n; |
| break; |
| |
| case NS_CMPRSFLGS: |
| if (srcp >= eom) { |
| return (-1); |
| } |
| if (len < 0) |
| len = srcp - src + 1; |
| srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff)); |
| if (srcp < msg || srcp >= eom) { /* 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 >= eom - msg) { |
| return (-1); |
| } |
| break; |
| |
| default: |
| return (-1); /* flag error */ |
| } |
| } |
| *dstp = '\0'; |
| if (len < 0) |
| len = srcp - src; |
| return (len); |
| } |
| |
| |
| /* |
| * dns_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 "". |
| */ |
| int |
| dns_ns_name_uncompress(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 = dns_ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1) |
| return (-1); |
| if (dns_ns_name_ntop(tmp, dst, dstsiz) == -1) |
| return (-1); |
| return (n); |
| } |
| |
| |
| /* |
| * dns_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. |
| */ |
| int |
| dns_ns_name_skip(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 */ |
| return (-1); |
| } |
| break; |
| } |
| if (cp > eom) { |
| return (-1); |
| } |
| *ptrptr = cp; |
| return (0); |
| } |
| |
| #endif /* HAVE_RESOLV */ |