RCS_ID_C="$Id: res_comp.c,v 1.3 1993/06/04 11:16:15 jraja Exp $"; /* * Copyright (c) 1993 AmiTCP/IP Group, * Helsinki University of Technology, Finland. * All rights reserved. * * Last modified: Fri Jun 4 00:33:20 1993 jraja * * HISTORY * $Log: res_comp.c,v $ * Revision 1.3 1993/06/04 11:16:15 jraja * Fixes for first public release. * * Revision 1.2 1993/06/02 19:26:17 too * Moved resolver stuff here from kern/ -directory * * Revision 1.1 1993/06/01 16:30:33 too * Initial revision * * Revision 1.1 93/04/25 12:46:13 12:46:13 too (Tomi Ollila) * Initial revision * * */ /* * Copyright (c) 1985 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)res_comp.c 6.22 (Berkeley) 3/19/91"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #include #include static int dn_find(u_char *exp_dn, u_char *msg, u_char **dnptrs, u_char **lastdnptr); /* * Expand compressed domain name 'comp_dn' to full domain name. * 'msg' is a pointer to the begining of the message, * 'eomorig' points to the first location after the message, * 'exp_dn' is a pointer to a buffer of size 'length' for the result. * Return size of compressed name or -1 if there was an error. */ int dn_expand(const u_char *msg, const u_char *eomorig, const u_char *comp_dn, u_char *exp_dn, int length) { register u_char *cp, *dn; register int n, c; u_char *eom; int len = -1, checked = 0; dn = exp_dn; cp = (u_char *)comp_dn; eom = exp_dn + length; /* * fetch next label in domain name */ while (n = *cp++) { /* * Check for indirection */ switch (n & INDIR_MASK) { case 0: 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++) == '.') { if (dn + n + 2 >= eom) return (-1); *dn++ = '\\'; } *dn++ = c; if (cp >= eomorig) /* out of range */ return(-1); } break; case INDIR_MASK: if (len < 0) len = cp - comp_dn + 1; cp = (u_char *)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); } /* * Compress domain name 'exp_dn' 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 arrary 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(const u_char *exp_dn, u_char *comp_dn, int length, 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; eob = cp + length; 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); } /* * Skip over a compressed domain name. Return the size or -1. */ int __dn_skipname(const u_char *comp_dn, const u_char *eom) { register u_char *cp; register int n; cp = (u_char *)comp_dn; while (cp < eom && (n = *cp++)) { /* * check for indirection */ switch (n & INDIR_MASK) { case 0: /* normal case, n == len */ cp += n; continue; default: /* illegal type */ return (-1); case INDIR_MASK: /* indirection */ cp++; } break; } return (cp - comp_dn); } /* * 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(u_char *exp_dn, u_char *msg, u_char **dnptrs, u_char **lastdnptr) { register u_char *dn, *cp, **cpp; register int n; u_char *sp; 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 (*dn++ != *cp++) goto next; } if ((n = *dn++) == '\0' && *cp == '\0') return (sp - msg); if (n == '.') continue; goto next; default: /* illegal type */ return (-1); case INDIR_MASK: /* indirection */ cp = msg + (((n & 0x3f) << 8) | *cp); } } if (*dn == '\0') return (sp - msg); next: ; } return (-1); } /* * Routines to insert/extract short/long's. Must account for byte * order and non-alignment problems. This code at least has the * advantage of being portable. * * used by sendmail. */ u_short _getshort(u_char *msgp) { register u_char *p = (u_char *) msgp; register u_short u; u = *p++ << 8; return ((u_short)(u | *p)); } u_long _getlong(u_char *msgp) { register u_char *p = (u_char *) msgp; register u_long u; u = *p++; u <<= 8; u |= *p++; u <<= 8; u |= *p++; u <<= 8; return (u | *p); } void __putshort(register u_short s, register u_char *msgp) { msgp[1] = s; msgp[0] = s >> 8; } void __putlong(register u_long l, register u_char *msgp) { msgp[3] = l; msgp[2] = (l >>= 8); msgp[1] = (l >>= 8); msgp[0] = l >> 8; }