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); 130