mDNSPosix/Client.c

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