mDNSPosix/Client.c

   1 /*
   2  * Copyright (c) 2002-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24
  25     Change History (most recent first):
  26
  27 $Log: Client.c,v $
  28 Revision 1.11  2003/11/17 20:14:32  cheshire
  29 Typo: Wrote "domC" where it should have said "domainC"
  30
  31 Revision 1.10  2003/11/14 21:27:09  cheshire
  32 <rdar://problem/3484766>: Security: Crashing bug in mDNSResponder
  33 Fix code that should use buffer size MAX_ESCAPED_DOMAIN_NAME (1005) instead of 256-byte buffers.
  34
  35 Revision 1.9  2003/08/14 02:19:55  cheshire
  36 <rdar://problem/3375491> Split generic ResourceRecord type into two separate types: AuthRecord and CacheRecord
  37
  38 Revision 1.8  2003/08/12 19:56:26  cheshire
  39 Update to APSL 2.0
  40
  41 Revision 1.7  2003/07/02 21:19:58  cheshire
  42 <rdar://problem/3313413> Update copyright notices, etc., in source code comments
  43
  44 Revision 1.6  2003/06/18 05:48:41  cheshire
  45 Fix warnings
  46
  47 Revision 1.5  2003/05/06 00:00:50  cheshire
  48 <rdar://problem/3248914> Rationalize naming of domainname manipulation functions
  49
  50 Revision 1.4  2002/12/23 22:13:31  jgraessl
  51
  52 Reviewed by: Stuart Cheshire
  53 Initial IPv6 support for mDNSResponder.
  54
  55 Revision 1.3  2002/09/21 20:44:53  zarzycki
  56 Added APSL info
  57
  58 Revision 1.2  2002/09/19 04:20:44  cheshire
  59 Remove high-ascii characters that confuse some systems
  60
  61 Revision 1.1  2002/09/17 06:24:35  cheshire
  62 First checkin
  63
  64 */
  65
  66 #include <assert.h>
  67 #include <signal.h>
  68 #include <stdio.h>
  69 #include <string.h>
  70 #include <unistd.h>
  71 #include <stdlib.h>
  72
  73 #include "mDNSClientAPI.h"// Defines the interface to the mDNS core code
  74 #include "mDNSPosix.h"    // Defines the specific types needed to run mDNS on this platform
  75 #include "ExampleClientApp.h"
  76
  77 // Globals
  78 static mDNS mDNSStorage;       // mDNS core uses this to store its globals
  79 static mDNS_PlatformSupport PlatformStorage;  // Stores this platform's globals
  80 #define RR_CACHE_SIZE 500
  81 static CacheRecord gRRCache[RR_CACHE_SIZE];
  82
  83 static const char *gProgramName = "mDNSResponderPosix";
  84
  85 static void BrowseCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, mDNSBool AddRecord)
  86     // A callback from the core mDNS code that indicates that we've received a
  87     // response to our query.  Note that this code runs on the main thread
  88     // (in fact, there is only one thread!), so we can safely printf the results.
  89 {
  90     domainlabel name;
  91     domainname  type;
  92     domainname  domain;
  93         char nameC  [MAX_DOMAIN_LABEL+1];                       // Unescaped name: up to 63 bytes plus C-string terminating NULL.
  94         char typeC  [MAX_ESCAPED_DOMAIN_NAME];
  95         char domainC[MAX_ESCAPED_DOMAIN_NAME];
  96     const char *state;
  97
  98         (void)m;                // Unused
  99         (void)question; // Unused
 100
 101     assert(answer->rrtype == kDNSType_PTR);
 102
 103     DeconstructServiceName(&answer->rdata->u.name, &name, &type, &domain);
 104
 105     ConvertDomainLabelToCString_unescaped(&name, nameC);
 106     ConvertDomainNameToCString(&type, typeC);
 107     ConvertDomainNameToCString(&domain, domainC);
 108
 109     // If the TTL has hit 0, the service is no longer available.
 110     if (!AddRecord) {
 111         state = "Lost ";
 112     } else {
 113         state = "Found";
 114     }
 115     fprintf(stderr, "*** %s name = '%s', type = '%s', domain = '%s'\n", state, nameC, typeC, domainC);
 116 }
 117
 118 static mDNSBool CheckThatServiceTypeIsUsable(const char *serviceType, mDNSBool printExplanation)
 119     // Checks that serviceType is a reasonable service type
 120     // label and, if it isn't and printExplanation is true, prints
 121     // an explanation of why not.
 122 {
 123     mDNSBool result;
 124
 125     result = mDNStrue;
 126     if (result && strlen(serviceType) > 63) {
 127         if (printExplanation) {
 128             fprintf(stderr,
 129                     "%s: Service type specified by -t is too long (must be 63 characters or less)\n",
 130                     gProgramName);
 131         }
 132         result = mDNSfalse;
 133     }
 134     if (result && serviceType[0] == 0) {
 135         if (printExplanation) {
 136             fprintf(stderr,
 137                     "%s: Service type specified by -t can't be empty\n",
 138                     gProgramName);
 139         }
 140         result = mDNSfalse;
 141     }
 142     return result;
 143 }
 144
 145 static const char kDefaultServiceType[] = "_afpovertcp._tcp.";
 146
 147 static void PrintUsage()
 148 {
 149     fprintf(stderr,
 150             "Usage: %s [-v level] [-t type]\n",
 151             gProgramName);
 152     fprintf(stderr, "          -v verbose mode, level is a number from 0 to 2\n");
 153     fprintf(stderr, "             0 = no debugging info (default)\n");
 154     fprintf(stderr, "             1 = standard debugging info\n");
 155     fprintf(stderr, "             2 = intense debugging info\n");
 156     fprintf(stderr, "          -t uses 'type' as the service type (default is '%s')\n", kDefaultServiceType);
 157 }
 158
 159 static const char *gServiceType      = kDefaultServiceType;
 160
 161 static void ParseArguments(int argc, char **argv)
 162     // Parses our command line arguments into the global variables
 163     // listed above.
 164 {
 165     int ch;
 166
 167     // Set gProgramName to the last path component of argv[0]
 168
 169     gProgramName = strrchr(argv[0], '/');
 170     if (gProgramName == NULL) {
 171         gProgramName = argv[0];
 172     } else {
 173         gProgramName += 1;
 174     }
 175
 176     // Parse command line options using getopt.
 177
 178     do {
 179         ch = getopt(argc, argv, "v:t:");
 180         if (ch != -1) {
 181             switch (ch) {
 182                 case 'v':
 183                     gMDNSPlatformPosixVerboseLevel = atoi(optarg);
 184                     if (gMDNSPlatformPosixVerboseLevel < 0 || gMDNSPlatformPosixVerboseLevel > 2) {
 185                         fprintf(stderr,
 186                                 "%s: Verbose mode must be in the range 0..2\n",
 187                                 gProgramName);
 188                         exit(1);
 189                     }
 190                     break;
 191                 case 't':
 192                     gServiceType = optarg;
 193                     if ( ! CheckThatServiceTypeIsUsable(gServiceType, mDNStrue) ) {
 194                         exit(1);
 195                     }
 196                     break;
 197                 case '?':
 198                 default:
 199                     PrintUsage();
 200                     exit(1);
 201                     break;
 202             }
 203         }
 204     } while (ch != -1);
 205
 206     // Check for any left over command line arguments.
 207
 208     if (optind != argc) {
 209         fprintf(stderr, "%s: Unexpected argument '%s'\n", gProgramName, argv[optind]);
 210         exit(1);
 211     }
 212 }
 213
 214 int main(int argc, char **argv)
 215     // The program's main entry point.  The program does a trivial
 216     // mDNS query, looking for all AFP servers in the local domain.
 217 {
 218     int     result;
 219     mStatus     status;
 220     DNSQuestion question;
 221     domainname  type;
 222     domainname  domain;
 223
 224     // Parse our command line arguments.  This won't come back if there's an error.
 225     ParseArguments(argc, argv);
 226
 227     // Initialise the mDNS core.
 228         status = mDNS_Init(&mDNSStorage, &PlatformStorage,
 229         gRRCache, RR_CACHE_SIZE,
 230         mDNS_Init_DontAdvertiseLocalAddresses,
 231         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 232     if (status == mStatus_NoError) {
 233
 234         // Construct and start the query.
 235
 236         MakeDomainNameFromDNSNameString(&type, gServiceType);
 237         MakeDomainNameFromDNSNameString(&domain, "local.");
 238
 239         status = mDNS_StartBrowse(&mDNSStorage, &question, &type, &domain, mDNSInterface_Any, BrowseCallback, NULL);
 240
 241         // Run the platform main event loop until the user types ^C.
 242         // The BrowseCallback routine is responsible for printing
 243         // any results that we find.
 244
 245         if (status == mStatus_NoError) {
 246             fprintf(stderr, "Hit ^C when you're bored waiting for responses.\n");
 247                 ExampleClientEventLoop(&mDNSStorage);
 248             mDNS_StopQuery(&mDNSStorage, &question);
 249                         mDNS_Close(&mDNSStorage);
 250         }
 251     }
 252
 253     if (status == mStatus_NoError) {
 254         result = 0;
 255     } else {
 256         result = 2;
 257     }
 258     if ( (result != 0) || (gMDNSPlatformPosixVerboseLevel > 0) ) {
 259         fprintf(stderr, "%s: Finished with status %ld, result %d\n", gProgramName, status, result);
 260     }
 261
 262     return 0;
 263 }