usr/src/lib/gss_mechs/mech_krb5/krb5/os/dnsglue.h

   1 /*
   2  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6 /*
   7  * lib/krb5/os/dnsglue.h
   8  *
   9  * Copyright 2004 by the Massachusetts Institute of Technology.
  10  * All Rights Reserved.
  11  *
  12  * Export of this software from the United States of America may
  13  *   require a specific license from the United States Government.
  14  *   It is the responsibility of any person or organization contemplating
  15  *   export to obtain such a license before exporting.
  16  *
  17  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  18  * distribute this software and its documentation for any purpose and
  19  * without fee is hereby granted, provided that the above copyright
  20  * notice appear in all copies and that both that copyright notice and
  21  * this permission notice appear in supporting documentation, and that
  22  * the name of M.I.T. not be used in advertising or publicity pertaining
  23  * to distribution of the software without specific, written prior
  24  * permission.  Furthermore if you modify this software you must label
  25  * your software as modified software and not distribute it in such a
  26  * fashion that it might be confused with the original M.I.T. software.
  27  * M.I.T. makes no representations about the suitability of
  28  * this software for any purpose.  It is provided "as is" without express
  29  * or implied warranty.
  30  *
  31  * Glue layer for DNS resolver, to make parsing of replies easier
  32  * whether we are using BIND 4, 8, or 9.
  33  */
  34
  35 /*
  36  * BIND 4 doesn't have the ns_initparse() API, so we need to do some
  37  * manual parsing via the HEADER struct.  BIND 8 does have
  38  * ns_initparse(), but has enums for the various protocol constants
  39  * rather than the BIND 4 macros.  BIND 9 (at least on Mac OS X
  40  * Panther) appears to disable res_nsearch() if BIND_8_COMPAT is
  41  * defined (which is necessary to obtain the HEADER struct).
  42  *
  43  * We use ns_initparse() if available at all, and never define
  44  * BIND_8_COMPAT.  If there is no ns_initparse(), we do manual parsing
  45  * by using the HEADER struct.
  46  */
  47
  48 #ifndef KRB5_DNSGLUE_H
  49 #define KRB5_DNSGLUE_H
  50
  51 #include "autoconf.h"
  52 #ifdef KRB5_DNS_LOOKUP
  53
  54 #include "k5-int.h"
  55 #include "os-proto.h"
  56 #ifdef WSHELPER
  57 #include <wshelper.h>
  58 #else /* WSHELPER */
  59 #include <netinet/in.h>
  60 #include <arpa/inet.h>
  61 #include <arpa/nameser.h>
  62 #include <resolv.h>
  63 #include <netdb.h>
  64 #endif /* WSHELPER */
  65
  66 #if HAVE_SYS_PARAM_H
  67 #include <sys/param.h>          /* for MAXHOSTNAMELEN */
  68 #endif
  69
  70 #ifndef MAXHOSTNAMELEN
  71 #define MAXHOSTNAMELEN 64       /* if we can't find it elswhere */
  72 #endif
  73
  74 #ifndef MAXDNAME
  75
  76 #ifdef NS_MAXDNAME
  77 #define MAXDNAME NS_MAXDNAME
  78 #else
  79 #ifdef MAXLABEL
  80 #define MAXDNAME (16 * MAXLABEL)
  81 #else
  82 #define MAXDNAME (16 * MAXHOSTNAMELEN)
  83 #endif
  84 #endif
  85
  86 #endif
  87
  88 #if HAVE_NS_INITPARSE
  89 /*
  90  * Solaris 7 has ns_rr_cl rather than ns_rr_class.
  91  */
  92 #if !defined(ns_rr_class) && defined(ns_rr_cl)
  93 #define ns_rr_class ns_rr_cl
  94 #endif
  95 #endif
  96
  97 #if HAVE_RES_NSEARCH
  98 /*
  99  * Some BIND 8 / BIND 9 implementations disable the BIND 4 style
 100  * constants.
 101  */
 102 #ifndef C_IN
 103 #define C_IN ns_c_in
 104 #endif
 105 #ifndef T_SRV
 106 #define T_SRV ns_t_srv
 107 #endif
 108 #ifndef T_TXT
 109 #define T_TXT ns_t_txt
 110 #endif
 111
 112 #else  /* !HAVE_RES_NSEARCH */
 113
 114 /*
 115  * Some BIND implementations might be old enough to lack these.
 116  */
 117 #ifndef T_TXT
 118 #define T_TXT 15
 119 #endif
 120 #ifndef T_SRV
 121 #define T_SRV 33
 122 #endif
 123
 124 #endif /* HAVE_RES_NSEARCH */
 125
 126 /*
 127  * INCR_OK
 128  *
 129  * Given moving pointer PTR offset from BASE, return true if adding
 130  * INCR to PTR doesn't move it PTR than MAX bytes from BASE.
 131  */
 132 #define INCR_OK(base, max, ptr, incr)                           \
 133     ((incr) <= (max) - ((const unsigned char *)(ptr)            \
 134                         - (const unsigned char *)(base)))
 135
 136 /*
 137  * SAFE_GETUINT16
 138  *
 139  * Given PTR offset from BASE, if at least INCR bytes are safe to
 140  * read, get network byte order uint16 into S, and increment PTR.  On
 141  * failure, goto LABEL.
 142  */
 143
 144 /* Solaris Kerberos */
 145 #define SAFE_GETUINT16(base, max, ptr, incr, s, label)  \
 146     do {                                                \
 147         if (!INCR_OK(base, max, ptr, incr)) goto label; \
 148         (s) = (unsigned short)(ptr)[0] << 8             \
 149             | (unsigned short)(ptr)[1];                 \
 150         (ptr) += (incr);                                        \
 151     } while (0)
 152
 153 struct krb5int_dns_state;
 154
 155 int krb5int_dns_init(struct krb5int_dns_state **, char *, int, int);
 156 int krb5int_dns_nextans(struct krb5int_dns_state *,
 157                         const unsigned char **, int *);
 158 int krb5int_dns_expand(struct krb5int_dns_state *,
 159                        const unsigned char *, char *, int);
 160 void krb5int_dns_fini(struct krb5int_dns_state *);
 161
 162 #endif /* KRB5_DNS_LOOKUP */
 163 #endif /* !defined(KRB5_DNSGLUE_H) */