/***************************************************************** ** ** @(#) domaincmp.c -- compare two domain names ** ** Copyright (c) Aug 2005, Karle Boss, Holger Zuleger (kaho). ** isparentdomain() (c) Mar 2010 by Holger Zuleger ** All rights reserved. ** ** This software is open source. ** ** Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions ** are met: ** ** Redistributions of source code must retain the above copyright notice, ** this list of conditions and the following disclaimer. ** ** 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. ** ** Neither the name of Karle Boss or Holger Zuleger (kaho) 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 COPYRIGHT HOLDERS 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. ** *****************************************************************/ # include <stdio.h> # include <string.h> # include <assert.h> # include <ctype.h> #define extern # include "domaincmp.h" #undef extern #define goto_labelstart(str, p) while ( (p) > (str) && *((p)-1) != '.' ) \ (p)-- /***************************************************************** ** int domaincmp (a, b) ** compare a and b as fqdns. ** return <0 | 0 | >0 as in strcmp ** A subdomain is less than the corresponding parent domain, ** thus domaincmp ("z.example.net", "example.net") return < 0 !! *****************************************************************/ int domaincmp (const char *a, const char *b) { return domaincmp_dir (a, b, 1); } /***************************************************************** ** int domaincmp_dir (a, b, subdomain_above) ** compare a and b as fqdns. ** return <0 | 0 | >0 as in strcmp ** A subdomain is less than the corresponding parent domain, ** thus domaincmp ("z.example.net", "example.net") return < 0 !! *****************************************************************/ int domaincmp_dir (const char *a, const char *b, int subdomain_above) { register const char *pa; register const char *pb; int dir; if ( a == NULL ) return -1; if ( b == NULL ) return 1; if ( subdomain_above ) dir = 1; else dir = -1; if ( *a == '.' ) /* skip a leading dot */ a++; if ( *b == '.' ) /* same at the other string */ b++; /* let pa and pb point to the last non dot char */ pa = a + strlen (a); do pa--; while ( pa > a && *pa == '.' ); pb = b + strlen (b); do pb--; while ( pb > b && *pb == '.' ); /* cmp both domains starting at the end */ while ( *pa == *pb && pa > a && pb > b ) pa--, pb--; if ( *pa != *pb ) /* both domains are different ? */ { if ( *pa == '.' ) pa++; /* set to beginning of next label */ else goto_labelstart (a, pa); /* find begin of current label */ if ( *pb == '.' ) pb++; /* set to beginning of next label */ else goto_labelstart (b, pb); /* find begin of current label */ } else /* maybe one of them has a subdomain */ { if ( pa > a ) if ( pa[-1] == '.' ) return -1 * dir; else goto_labelstart (a, pa); else if ( pb > b ) if ( pb[-1] == '.' ) return 1 * dir; else goto_labelstart (b, pb); else return 0; /* both are at the beginning, so they are equal */ } /* both domains are definitly unequal */ while ( *pa == *pb ) /* so we have to look at the point where they differ */ pa++, pb++; return *pa - *pb; } /***************************************************************** ** ** int issubdomain ("child", "parent") ** ** "child" and "parent" are standardized domain names in such ** a way that even both domain names are ending with a dot, ** or none of them. ** ** returns 1 if "child" is a subdomain of "parent" ** returns 0 if "child" is not a subdomain of "parent" ** *****************************************************************/ int issubdomain (const char *child, const char *parent) { const char *p; const char *cdot; const char *pdot; int ccnt; int pcnt; if ( !child || !parent || *child == '\0' || *parent == '\0' ) return 0; pdot = cdot = NULL; pcnt = 0; for ( p = parent; *p; p++ ) if ( *p == '.' ) { if ( pcnt == 0 ) pdot = p; pcnt++; } ccnt = 0; for ( p = child; *p; p++ ) if ( *p == '.' ) { if ( ccnt == 0 ) cdot = p; ccnt++; } if ( ccnt == 0 ) /* child is not a fqdn or is not deep enough ? */ return 0; if ( pcnt == 0 ) /* parent is not a fqdn ? */ return 0; if ( pcnt >= ccnt ) /* parent has more levels than child ? */ return 0; /* is child a (one level) subdomain of parent ? */ if ( strcmp (cdot+1, parent) == 0 ) /* the domains are equal ? */ return 1; return 0; } /***************************************************************** ** ** int isparentdomain ("child", "parent", level) ** ** "child" and "parent" are standardized domain names in such ** a way that even both domain names are ending with a dot, ** or none of them. ** ** returns 1 if "child" is a subdomain of "parent" ** returns 0 if "child" is not a subdomain of "parent" ** returns -1 if "child" and "parent" are the same domain ** *****************************************************************/ int isparentdomain (const char *child, const char *parent, int level) { const char *p; const char *cdot; const char *pdot; int ccnt; int pcnt; if ( !child || !parent || *child == '\0' || *parent == '\0' ) return 0; pdot = cdot = NULL; pcnt = 0; for ( p = parent; *p; p++ ) if ( *p == '.' ) { if ( pcnt == 0 ) pdot = p; pcnt++; } ccnt = 0; for ( p = child; *p; p++ ) if ( *p == '.' ) { if ( ccnt == 0 ) cdot = p; ccnt++; } if ( ccnt == 0 || ccnt < level ) /* child is not a fqdn or is not deep enough ? */ return 0; if ( pcnt == 0 ) /* parent is not a fqdn ? */ return 0; if ( pcnt > ccnt ) /* parent has more levels than child ? */ return 0; if ( pcnt == ccnt ) /* both are at the same level ? */ { /* let's check the domain part */ if ( strcmp (cdot, pdot) == 0 ) /* the domains are equal ? */ return -1; return 0; } if ( pcnt > ccnt ) /* parent has more levels than child ? */ return 0; /* is child a (one level) subdomain of parent ? */ if ( strcmp (cdot+1, parent) == 0 ) /* the domains are equal ? */ return 1; return 0; } #ifdef DOMAINCMP_TEST static struct { char *a; char *b; int res; } ex[] = { { ".", ".", 0 }, { "test", "", 1 }, { "", "test2", -1 }, { "", "", 0 }, { "de", "de", 0 }, { ".de", "de", 0 }, { "de.", "de.", 0 }, { ".de", ".de", 0 }, { ".de.", ".de.", 0 }, { ".de", "zde", -1 }, { ".de", "ade", 1 }, { "zde", ".de", 1 }, { "ade", ".de", -1 }, { "a.de", ".de", -1 }, { ".de", "a.de", 1 }, { "a.de", "b.de", -1 }, { "a.de.", "b.de", -1 }, { "a.de", "b.de.", -1 }, { "a.de", "a.de.", 0 }, { "aa.de", "b.de", -1 }, { "ba.de", "b.de", 1 }, { "a.de", "a.dk", -1 }, { "anna.example.de", "anna.example.de", 0 }, { "anna.example.de", "annamirl.example.de", -1 }, { "anna.example.de", "ann.example.de", 1 }, { "example.de.", "xy.example.de.", 1 }, { "example.de.", "ab.example.de.", 1 }, { "example.de", "ab.example.de", 1 }, { "xy.example.de.", "example.de.", -1 }, { "ab.example.de.", "example.de.", -1 }, { "ab.example.de", "example.de", -1 }, { "ab.mast.de", "axt.de", 1 }, { "ab.mast.de", "obt.de", -1 }, { "abc.example.de.", "xy.example.de.", -1 }, { NULL, NULL, 0 } }; const char *progname; main (int argc, char *argv[]) { int expect; int res; int c; int i; progname = *argv; for ( i = 0; ex[i].a; i++ ) { expect = ex[i].res; if ( expect < 0 ) c = '<'; else if ( expect > 0 ) c = '>'; else c = '='; printf ("%-20s %-20s ", ex[i].a, ex[i].b); printf ("%3d ", issubdomain (ex[i].a, ex[i].b)); printf ("\t==> 0 %c ", c); fflush (stdout); res = domaincmp (ex[i].a, ex[i].b); printf ("%3d ", res); if ( res < 0 && expect < 0 || res > 0 && expect > 0 || res == 0 && expect == 0 ) puts ("ok"); else puts ("not ok"); } } #endif