usr/src/lib/gss_mechs/mech_krb5/include/cache-addrinfo.h

   1
   2 /*
   3  * Copyright (C) 2004 by the Massachusetts Institute of Technology,
   4  * Cambridge, MA, USA.  All Rights Reserved.
   5  *
   6  * This software is being provided to you, the LICENSEE, by the
   7  * Massachusetts Institute of Technology (M.I.T.) under the following
   8  * license.  By obtaining, using and/or copying this software, you agree
   9  * that you have read, understood, and will comply with these terms and
  10  * conditions:
  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 distribute
  18  * this software and its documentation for any purpose and without fee or
  19  * royalty is hereby granted, provided that you agree to comply with the
  20  * following copyright notice and statements, including the disclaimer, and
  21  * that the same appear on ALL copies of the software and documentation,
  22  * including modifications that you make for internal use or for
  23  * distribution:
  24  *
  25  * THIS SOFTWARE IS PROVIDED "AS IS", AND M.I.T. MAKES NO REPRESENTATIONS
  26  * OR WARRANTIES, EXPRESS OR IMPLIED.  By way of example, but not
  27  * limitation, M.I.T. MAKES NO REPRESENTATIONS OR WARRANTIES OF
  28  * MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF
  29  * THE LICENSED SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
  30  * PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
  31  *
  32  * The name of the Massachusetts Institute of Technology or M.I.T. may NOT
  33  * be used in advertising or publicity pertaining to distribution of the
  34  * software.  Title to copyright in this software and any associated
  35  * documentation shall at all times remain with M.I.T., and USER agrees to
  36  * preserve same.
  37  *
  38  * Furthermore if you modify this software you must label
  39  * your software as modified software and not distribute it in such a
  40  * fashion that it might be confused with the original M.I.T. software.
  41  */
  42
  43 /* Approach overview:
  44
  45    If a system version is available but buggy, save handles to it,
  46    redefine the names to refer to static functions defined here, and
  47    in those functions, call the system versions and fix up the
  48    returned data.  Use the native data structures and flag values.
  49
  50    If no system version exists, use gethostby* and fake it.  Define
  51    the data structures and flag values locally.
  52
  53
  54    On Mac OS X, getaddrinfo results aren't cached (though
  55    gethostbyname results are), so we need to build a cache here.  Now
  56    things are getting really messy.  Because the cache is in use, we
  57    use getservbyname, and throw away thread safety.  (Not that the
  58    cache is thread safe, but when we get locking support, that'll be
  59    dealt with.)  This code needs tearing down and rebuilding, soon.
  60
  61
  62    Note that recent Windows developers' code has an interesting hack:
  63    When you include the right header files, with the right set of
  64    macros indicating system versions, you'll get an inline function
  65    that looks for getaddrinfo (or whatever) in the system library, and
  66    calls it if it's there.  If it's not there, it fakes it with
  67    gethostby* calls.
  68
  69    We're taking a simpler approach: A system provides these routines or
  70    it does not.
  71
  72    Someday, we may want to take into account different versions (say,
  73    different revs of GNU libc) where some are broken in one way, and
  74    some work or are broken in another way.  Cross that bridge when we
  75    come to it.  */
  76
  77 /* To do, maybe:
  78
  79    + For AIX 4.3.3, using the RFC 2133 definition: Implement
  80      AI_NUMERICHOST.  It's not defined in the header file.
  81
  82      For certain (old?) versions of GNU libc, AI_NUMERICHOST is
  83      defined but not implemented.
  84
  85    + Use gethostbyname2, inet_aton and other IPv6 or thread-safe
  86      functions if available.  But, see
  87      http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=135182 for one
  88      gethostbyname2 problem on Linux.  And besides, if a platform is
  89      supporting IPv6 at all, they really should be doing getaddrinfo
  90      by now.
  91
  92    + inet_ntop, inet_pton
  93
  94    + Conditionally export/import the function definitions, so a
  95      library can have a single copy instead of multiple.
  96
  97    + Upgrade host requirements to include working implementations of
  98      these functions, and throw all this away.  Pleeease?  :-)  */
  99
 100 #include "port-sockets.h"
 101 #include "socket-utils.h"
 102 #include "k5-platform.h"
 103 #include "k5-thread.h"
 104
 105 #include "fake-addrinfo.h"
 106
 107 #if defined (__APPLE__) && defined (__MACH__)
 108 #define FAI_CACHE
 109 #endif
 110
 111 struct face {
 112     struct in_addr *addrs4;
 113     struct in6_addr *addrs6;
 114     unsigned int naddrs4, naddrs6;
 115     time_t expiration;
 116     char *canonname, *name;
 117     struct face *next;
 118 };
 119
 120 /* fake addrinfo cache */
 121 struct fac {
 122     k5_mutex_t lock;
 123     struct face *data;
 124 };
 125
 126 extern struct fac krb5int_fac;
 127
 128 extern int krb5int_init_fac (void);
 129 extern void krb5int_fini_fac (void);