/** BEGIN COPYRIGHT BLOCK
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; version 2 of the License.
 * 
 * This Program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this Program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA.
 * 
 * In addition, as a special exception, Red Hat, Inc. gives You the additional
 * right to link the code of this Program with code not covered under the GNU
 * General Public License ("Non-GPL Code") and to distribute linked combinations
 * including the two, subject to the limitations in this paragraph. Non-GPL Code
 * permitted under this exception must only link to the code of this Program
 * through those well defined interfaces identified in the file named EXCEPTION
 * found in the source code files (the "Approved Interfaces"). The files of
 * Non-GPL Code may instantiate templates or use macros or inline functions from
 * the Approved Interfaces without causing the resulting work to be covered by
 * the GNU General Public License. Only Red Hat, Inc. may make changes or
 * additions to the list of Approved Interfaces. You must obey the GNU General
 * Public License in all respects for all of the Program code and other code used
 * in conjunction with the Program except the Non-GPL Code covered by this
 * exception. If you modify this file, you may extend this exception to your
 * version of the file, but you are not obligated to do so. If you do not wish to
 * provide this exception without modification, you must delete this exception
 * statement from your version and license this file solely under the GPL without
 * exception. 
 * 
 * 
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif


/*	lasdns.c
 *	This file contains the DNS LAS code.
 */

#include <stdio.h>
#include <string.h>

#ifdef	XP_WIN32
/* #include <winsock2.h> */
#include <winsock.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif

#include <netsite.h>
extern "C" {
#include <prnetdb.h>
}
#include <base/plist.h>
#include <base/pool.h>
#include <libaccess/nserror.h>
#include <libaccess/nsauth.h>
#include <libaccess/acl.h>
#include "aclpriv.h"
#include <libaccess/aclproto.h>
#include <libaccess/las.h>
#include "lasdns.h"
#include "aclutil.h"
#include "aclcache.h"
#include "permhash.h"
#include <libaccess/dbtlibaccess.h>
#include <libaccess/aclerror.h>
#include "access_plhash.h"
extern "C" {
#include <nspr.h>
}

#ifdef	UTEST
extern int LASDnsGetDns(char **dnsv);
#endif

/*    LASDnsMatch
 *    Given an array of fully-qualified dns names, tries to match them 
 *    against a given hash table.
 *    INPUT
 *    dns	DNS string	
 *    context	pointer to an LAS DNS context structure
 *
 *				In our usage, this context is derived from
 *				an acllist cache, which is a representation of
 *				of some global acis--in other words it's a global thing
 *				shared between threads--hence the use
 *				of the "read-only" hash lookup routines here.
 */
int
LASDnsMatch(char *token, LASDnsContext_t *context)
{

    /* Test for the unusual case where "*" is allowed */
    if (ACL_HashTableLookup_const(context->Table, "*"))
        return LAS_EVAL_TRUE;

    /*  Start with the full name.  Then strip off each component
     *  leaving the remainder starting with a period.  E.g.
     *    splash.mcom.com
     *    .mcom.com
     *    .com
     *  Search the hash table for each remaining portion.  Remember that
     *  wildcards were put in with the leading period intact.
     */
    do {
	if (ACL_HashTableLookup_const(context->Table, token))
            return LAS_EVAL_TRUE;

        token = strchr(&token[1], '.');
    } while (token != NULL);

    return LAS_EVAL_FALSE;

}

/*  LASDNSBuild
 *  Builds a hash table of all the hostnames provided (plus their aliases
 *  if aliasflg is true).  Wildcards are only permitted in the leftmost
 *  field.  They're represented in the hash table by a leading period.
 *  E.g. ".mcom.com".
 *
 *  RETURNS	Zero on success, else LAS_EVAL_INVALID
 */
int
LASDnsBuild(NSErr_t *errp, char *attr_pattern, LASDnsContext_t *context, int aliasflg)
{
    size_t	delimiter;    	/* length of valid token	*/
    char	token[256];    	/* max length dns name		*/
    int		i;
    int		ipcnt = 0;
    char	**p;
    unsigned long	*ipaddrs=0;
    pool_handle_t *pool;
    PRStatus	error=PR_SUCCESS;
    char	buffer[PR_NETDB_BUF_SIZE];
#ifdef	UTEST
    struct hostent *he, host;
#else
    PRHostEnt *he, host;
#endif

    if (attr_pattern == NULL) {
	nserrGenerate(errp, ACLERRINVAL, ACLERR4770, ACL_Program, 1, 
		      XP_GetAdminStr(DBT_lasdnsbuildInvalidAttributePattern_));
        return LAS_EVAL_INVALID;
    }

    context->Table = PR_NewHashTable(0,
				     PR_HashCaseString,
				     PR_CompareCaseStrings,
				     PR_CompareValues,
				     &ACLPermAllocOps,
				     NULL);
    pool = pool_create();
    context->pool = pool;
    if ((!context->Table) || (!context->pool)) {
	nserrGenerate(errp, ACLERRNOMEM, ACLERR4700, ACL_Program, 1, 
		      XP_GetAdminStr(DBT_lasdnsbuildUnableToAllocateHashT_));
        return LAS_EVAL_INVALID;
    }

    do {
		size_t maxsize = sizeof(token);
	/*  Get a single hostname from the pattern string	*/
        delimiter    = strcspn(attr_pattern, ", \t");
		if (delimiter >= maxsize) {
			delimiter = maxsize-1;
		}
        PL_strncpyz(token, attr_pattern, delimiter + 1);
        token[delimiter] = '\0';

        /*  Skip any white space after the token 		*/
        attr_pattern     += delimiter;
        attr_pattern    += strspn(attr_pattern, ", \t");

        /*  If there's a wildcard, strip it off but leave the "."
	 *  Can't have aliases for a wildcard pattern.
	 *  Treat "*" as a special case.  If so, go ahead and hash it.
	 */
        if (token[0] == '*') {
	    if (token[1] != '\0') {
	        if (!PR_HashTableAdd(context->Table, pool_strdup(pool, &token[1]), (void *)-1)) {
		    nserrGenerate(errp, ACLERRFAIL, ACLERR4710, ACL_Program, 2, 
				  XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), token);
	            return LAS_EVAL_INVALID;
	        }
	    } else {
	        if (!PR_HashTableAdd(context->Table, pool_strdup(pool, token), (void *)-1)) {
		    nserrGenerate(errp, ACLERRFAIL, ACLERR4720, ACL_Program, 2, XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), token);
	            return LAS_EVAL_INVALID;
	        }
	    }
	} else  {
	/*  This is a single hostname add it to the hash table	*/
	  if (!PR_HashTableAdd(context->Table, pool_strdup(pool, &token[0]), (void *)-1)) {
	    nserrGenerate(errp, ACLERRFAIL, ACLERR4730, ACL_Program, 2, XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), token);
	    return LAS_EVAL_INVALID;
	  }

	  if (aliasflg) {
	    /*		memset(buffer, '\0', PR_NETDB_BUF_SIZE);
	     */
#ifdef	UTEST
	    he = gethostbyname(token);
#else
	    error = PR_GetHostByName(token, 
				     buffer, 
				     PR_NETDB_BUF_SIZE, 
				     &host);
	    if (error == PR_SUCCESS) he = &host;
	    else he = NULL;
#endif
	    if (he) {
	      /* Make a copy of the list of IP addresses if any */
	      if (he->h_addr_list && he->h_addr_list[0]) {
 
		/* Count the IP addresses */
		for (p = he->h_addr_list, ipcnt = 0; *p; ++p) {
		  ++ipcnt;
		}
                 
		/* Allocate space */
		ipaddrs = (unsigned long *)PERM_MALLOC(ipcnt * sizeof(unsigned long));
 
		/* Copy IP addresses */
		for (i = 0; i < ipcnt; ++i) {
		  ipaddrs[i] = 0;
		  memcpy((void *)&ipaddrs[i], he->h_addr_list[i], 4);
		}
	      }
                 
	      /* Add each of the aliases to the list */
	      if (he->h_aliases && he->h_aliases[0]) {
                 
		for (p = he->h_aliases; *p; ++p) {
		  /*  Add it to the hash table			*/
		  if (!PR_HashTableAdd(context->Table, pool_strdup(pool, *p), (void*)-1)) {
		    nserrGenerate(errp, ACLERRFAIL, ACLERR4740, ACL_Program, 2, 
				  XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), *p);
		    PERM_FREE(ipaddrs);
		    return LAS_EVAL_INVALID;
		  }
		}
	      }
                 
	      for (i = 0; i < ipcnt; ++i) {

#ifdef UTEST
		he = gethostbyaddr((char *)&ipaddrs[i], 4, AF_INET);
#else
		error = PR_GetHostByAddr((PRNetAddr *)&ipaddrs[i], 
					    buffer, 
					    PR_NETDB_BUF_SIZE, 
					    &host);
		if (error == PR_SUCCESS) he = &host;
		else he = NULL;
#endif
		if (he) {
		  if (he->h_name) {
		    /*  Add it to the hash table			*/
		    if (!PR_HashTableAdd(context->Table, pool_strdup(pool, he->h_name),
					 (void *)-1)) {
		      nserrGenerate(errp, ACLERRFAIL, ACLERR4750, ACL_Program, 2, 
				    XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), he->h_name);
		      PERM_FREE(ipaddrs);
		      return LAS_EVAL_INVALID;
		    }
		  }
                 
		  if (he->h_aliases && he->h_aliases[0]) {
		    for (p = he->h_aliases; *p; ++p) {
		      /*  Add it to the hash table			*/
		      if (!PR_HashTableAdd(context->Table, pool_strdup(pool, *p), (void *)-1)) {
			nserrGenerate(errp, ACLERRFAIL, ACLERR4760, ACL_Program, 2,
				      XP_GetAdminStr(DBT_lasdnsbuildUnableToAddKeySN_), *p);
			PERM_FREE(ipaddrs);
			return LAS_EVAL_INVALID;
		      }
		    }
		  }
		}
	      }

	      PERM_FREE(ipaddrs);
	      ipaddrs = NULL;

	    }	/* if he */


	  }	/* if aliasflg */

	}	/* else - single hostname */


    } while ((attr_pattern != NULL) && 
	     (attr_pattern[0] != '\0') && 
	     (delimiter != 0));

    return 0;
}

/*  LASDnsFlush
 *  Given the address of a las_cookie for a DNS expression entry, frees up 
 *  all allocated memory for it.  This includes the hash table, plus the
 *  context structure.
 */
void
LASDnsFlush(void **las_cookie)
{
    if (*las_cookie == NULL)
        return;

    pool_destroy(((LASDnsContext_t *)*las_cookie)->pool);
    PR_HashTableDestroy(((LASDnsContext_t *)*las_cookie)->Table);
    PERM_FREE(*las_cookie);
    *las_cookie = NULL;
    return;
}

/*
 *	LASDnsEval
 *	INPUT
 *	attr_name	The string "dns" - in lower case.
 *	comparator	CMP_OP_EQ or CMP_OP_NE only
 *	attr_pattern	A comma-separated list of DNS names
 *			Any segment(s) in a DNS name can be wildcarded using
 *			"*".  Note that this is not a true Regular Expression
 *			form.
 *	*cachable	Always set to ACL_INDEF_CACHE
 *      subject		Subject property list
 *      resource 	Resource property list
 *      auth_info	Authentication info, if any
 *	RETURNS
 *	ret code	The usual LAS return codes.
 */
int LASDnsEval(NSErr_t *errp, char *attr_name, CmpOp_t comparator,
           char *attr_pattern, ACLCachable_t *cachable, void **LAS_cookie,
           PList_t subject, PList_t resource,
           PList_t auth_info, PList_t global_auth)
{
    int			result;
    int			aliasflg;
    char		*my_dns;
    LASDnsContext_t 	*context = NULL;
    int			rv;

    *cachable = ACL_INDEF_CACHABLE;

    if (strcmp(attr_name, "dns") == 0) 
	aliasflg = 0;
    else if (strcmp(attr_name, "dnsalias") == 0)
	aliasflg = 1;
    else {
	nserrGenerate(errp, ACLERRINVAL, ACLERR4800, ACL_Program, 2, XP_GetAdminStr(DBT_lasDnsBuildReceivedRequestForAtt_), attr_name);
    	return LAS_EVAL_INVALID;
    }

    if ((comparator != CMP_OP_EQ) && (comparator != CMP_OP_NE)) {
	nserrGenerate(errp, ACLERRINVAL, ACLERR4810, ACL_Program, 2, XP_GetAdminStr(DBT_lasdnsevalIllegalComparatorDN_), comparator_string(comparator));
    	return LAS_EVAL_INVALID;
    }

    /* If this is the first time through, build the pattern tree first.  */
    if (*LAS_cookie == NULL) {
        ACL_CritEnter();
        if (*LAS_cookie == NULL) {	/* Must check again */
            *LAS_cookie = context = 
                (LASDnsContext_t *)PERM_MALLOC(sizeof(LASDnsContext_t));
            if (context == NULL) {
                nserrGenerate(errp, ACLERRNOMEM, ACLERR4820, ACL_Program, 1, XP_GetAdminStr(DBT_lasdnsevalUnableToAllocateContex_));
                ACL_CritExit();
                return LAS_EVAL_FAIL;
            }
            context->Table = NULL;
            LASDnsBuild(errp, attr_pattern, context, aliasflg);
        } else {
            context = (LASDnsContext *) *LAS_cookie;
        }
        ACL_CritExit();
    } else {
        ACL_CritEnter();
        context = (LASDnsContext *) *LAS_cookie;
        ACL_CritExit();
    }

    /* Call the DNS attribute getter */
#ifdef  UTEST
    LASDnsGetDns(&my_dns);      /* gets stuffed on return       */
#else
    rv = ACL_GetAttribute(errp, ACL_ATTR_DNS, (void **)&my_dns,
			  subject, resource, auth_info, global_auth);

    if (rv != LAS_EVAL_TRUE) {
        if (subject || resource) {	
	    char rv_str[16];
            /* Don't ereport if called from ACL_CachableAclList */
	    sprintf(rv_str, "%d", rv);
	    nserrGenerate(errp, ACLERRINVAL, ACLERR4830, ACL_Program, 2, XP_GetAdminStr(DBT_lasdnsevalUnableToGetDnsErrorDN_), rv_str);
        }
	return LAS_EVAL_FAIL;
    }
#endif

    result = LASDnsMatch(my_dns, context);

    if (comparator == CMP_OP_NE) {
    	if (result == LAS_EVAL_FALSE)
            return LAS_EVAL_TRUE;
        else if (result == LAS_EVAL_TRUE)
            return LAS_EVAL_FALSE;
    }
    return (result);
}