mDNSPosix/Client.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved.
   4  *
   5  * @APPLE_LICENSE_HEADER_START@
   6  *
   7  * This file contains Original Code and/or Modifications of Original Code
   8  * as defined in and that are subject to the Apple Public Source License
   9  * Version 2.0 (the 'License'). You may not use this file except in
  10  * compliance with the License. Please obtain a copy of the License at
  11  * http://www.opensource.apple.com/apsl/ and read it before using this
  12  * file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23
  24     Change History (most recent first):
  25
  26 $Log: Client.c,v $
  27 Revision 1.15  2004/12/16 20:17:11  cheshire
  28 <rdar://problem/3324626> Cache memory management improvements
  29
  30 Revision 1.14  2004/11/30 22:37:00  cheshire
  31 Update copyright dates and add "Mode: C; tab-width: 4" headers
  32
  33 Revision 1.13  2004/10/19 21:33:20  cheshire
  34 <rdar://problem/3844991> Cannot resolve non-local registrations using the mach API
  35 Added flag 'kDNSServiceFlagsForceMulticast'. Passing through an interface id for a unicast name
  36 doesn't force multicast unless you set this flag to indicate explicitly that this is what you want
  37
  38 Revision 1.12  2004/09/17 01:08:53  cheshire
  39 Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
  40   The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
  41   declared in that file are ONLY appropriate to single-address-space embedded applications.
  42   For clients on general-purpose computers, the interfaces defined in dns_sd.h should be used.
  43
  44 Revision 1.11  2003/11/17 20:14:32  cheshire
  45 Typo: Wrote "domC" where it should have said "domainC"
  46
  47 Revision 1.10  2003/11/14 21:27:09  cheshire
  48 <rdar://problem/3484766>: Security: Crashing bug in mDNSResponder
  49 Fix code that should use buffer size MAX_ESCAPED_DOMAIN_NAME (1005) instead of 256-byte buffers.
  50
  51 Revision 1.9  2003/08/14 02:19:55  cheshire
  52 <rdar://problem/3375491> Split generic ResourceRecord type into two separate types: AuthRecord and CacheRecord
  53
  54 Revision 1.8  2003/08/12 19:56:26  cheshire
  55 Update to APSL 2.0
  56
  57 Revision 1.7  2003/07/02 21:19:58  cheshire
  58 <rdar://problem/3313413> Update copyright notices, etc., in source code comments
  59
  60 Revision 1.6  2003/06/18 05:48:41  cheshire
  61 Fix warnings
  62
  63 Revision 1.5  2003/05/06 00:00:50  cheshire
  64 <rdar://problem/3248914> Rationalize naming of domainname manipulation functions
  65
  66 Revision 1.4  2002/12/23 22:13:31  jgraessl
  67
  68 Reviewed by: Stuart Cheshire
  69 Initial IPv6 support for mDNSResponder.
  70
  71 Revision 1.3  2002/09/21 20:44:53  zarzycki
  72 Added APSL info
  73
  74 Revision 1.2  2002/09/19 04:20:44  cheshire
  75 Remove high-ascii characters that confuse some systems
  76
  77 Revision 1.1  2002/09/17 06:24:35  cheshire
  78 First checkin
  79
  80 */
  81
  82 #include <assert.h>
  83 #include <signal.h>
  84 #include <stdio.h>
  85 #include <string.h>
  86 #include <unistd.h>
  87 #include <stdlib.h>
  88
  89 #include "mDNSEmbeddedAPI.h"// Defines the interface to the mDNS core code
  90 #include "mDNSPosix.h"    // Defines the specific types needed to run mDNS on this platform
  91 #include "ExampleClientApp.h"
  92
  93 // Globals
  94 static mDNS mDNSStorage;       // mDNS core uses this to store its globals
  95 static mDNS_PlatformSupport PlatformStorage;  // Stores this platform's globals
  96 #define RR_CACHE_SIZE 500
  97 static CacheEntity gRRCache[RR_CACHE_SIZE];
  98
  99 static const char *gProgramName = "mDNSResponderPosix";
 100
 101 static void BrowseCallback(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, mDNSBool AddRecord)
 102     // A callback from the core mDNS code that indicates that we've received a
 103     // response to our query.  Note that this code runs on the main thread
 104     // (in fact, there is only one thread!), so we can safely printf the results.
 105 {
 106     domainlabel name;
 107     domainname  type;
 108     domainname  domain;
 109         char nameC  [MAX_DOMAIN_LABEL+1];                       // Unescaped name: up to 63 bytes plus C-string terminating NULL.
 110         char typeC  [MAX_ESCAPED_DOMAIN_NAME];
 111         char domainC[MAX_ESCAPED_DOMAIN_NAME];
 112     const char *state;
 113
 114         (void)m;                // Unused
 115         (void)question; // Unused
 116
 117     assert(answer->rrtype == kDNSType_PTR);
 118
 119     DeconstructServiceName(&answer->rdata->u.name, &name, &type, &domain);
 120
 121     ConvertDomainLabelToCString_unescaped(&name, nameC);
 122     ConvertDomainNameToCString(&type, typeC);
 123     ConvertDomainNameToCString(&domain, domainC);
 124
 125     // If the TTL has hit 0, the service is no longer available.
 126     if (!AddRecord) {
 127         state = "Lost ";
 128     } else {
 129         state = "Found";
 130     }
 131     fprintf(stderr, "*** %s name = '%s', type = '%s', domain = '%s'\n", state, nameC, typeC, domainC);
 132 }
 133
 134 static mDNSBool CheckThatServiceTypeIsUsable(const char *serviceType, mDNSBool printExplanation)
 135     // Checks that serviceType is a reasonable service type
 136     // label and, if it isn't and printExplanation is true, prints
 137     // an explanation of why not.
 138 {
 139     mDNSBool result;
 140
 141     result = mDNStrue;
 142     if (result && strlen(serviceType) > 63) {
 143         if (printExplanation) {
 144             fprintf(stderr,
 145                     "%s: Service type specified by -t is too long (must be 63 characters or less)\n",
 146                     gProgramName);
 147         }
 148         result = mDNSfalse;
 149     }
 150     if (result && serviceType[0] == 0) {
 151         if (printExplanation) {
 152             fprintf(stderr,
 153                     "%s: Service type specified by -t can't be empty\n",
 154                     gProgramName);
 155         }
 156         result = mDNSfalse;
 157     }
 158     return result;
 159 }
 160
 161 static const char kDefaultServiceType[] = "_afpovertcp._tcp.";
 162
 163 static void PrintUsage()
 164 {
 165     fprintf(stderr,
 166             "Usage: %s [-v level] [-t type]\n",
 167             gProgramName);
 168     fprintf(stderr, "          -v verbose mode, level is a number from 0 to 2\n");
 169     fprintf(stderr, "             0 = no debugging info (default)\n");
 170     fprintf(stderr, "             1 = standard debugging info\n");
 171     fprintf(stderr, "             2 = intense debugging info\n");
 172     fprintf(stderr, "          -t uses 'type' as the service type (default is '%s')\n", kDefaultServiceType);
 173 }
 174
 175 static const char *gServiceType      = kDefaultServiceType;
 176
 177 static void ParseArguments(int argc, char **argv)
 178     // Parses our command line arguments into the global variables
 179     // listed above.
 180 {
 181     int ch;
 182
 183     // Set gProgramName to the last path component of argv[0]
 184
 185     gProgramName = strrchr(argv[0], '/');
 186     if (gProgramName == NULL) {
 187         gProgramName = argv[0];
 188     } else {
 189         gProgramName += 1;
 190     }
 191
 192     // Parse command line options using getopt.
 193
 194     do {
 195         ch = getopt(argc, argv, "v:t:");
 196         if (ch != -1) {
 197             switch (ch) {
 198                 case 'v':
 199                     gMDNSPlatformPosixVerboseLevel = atoi(optarg);
 200                     if (gMDNSPlatformPosixVerboseLevel < 0 || gMDNSPlatformPosixVerboseLevel > 2) {
 201                         fprintf(stderr,
 202                                 "%s: Verbose mode must be in the range 0..2\n",
 203                                 gProgramName);
 204                         exit(1);
 205                     }
 206                     break;
 207                 case 't':
 208                     gServiceType = optarg;
 209                     if ( ! CheckThatServiceTypeIsUsable(gServiceType, mDNStrue) ) {
 210                         exit(1);
 211                     }
 212                     break;
 213                 case '?':
 214                 default:
 215                     PrintUsage();
 216                     exit(1);
 217                     break;
 218             }
 219         }
 220     } while (ch != -1);
 221
 222     // Check for any left over command line arguments.
 223
 224     if (optind != argc) {
 225         fprintf(stderr, "%s: Unexpected argument '%s'\n", gProgramName, argv[optind]);
 226         exit(1);
 227     }
 228 }
 229
 230 int main(int argc, char **argv)
 231     // The program's main entry point.  The program does a trivial
 232     // mDNS query, looking for all AFP servers in the local domain.
 233 {
 234     int     result;
 235     mStatus     status;
 236     DNSQuestion question;
 237     domainname  type;
 238     domainname  domain;
 239
 240     // Parse our command line arguments.  This won't come back if there's an error.
 241     ParseArguments(argc, argv);
 242
 243     // Initialise the mDNS core.
 244         status = mDNS_Init(&mDNSStorage, &PlatformStorage,
 245         gRRCache, RR_CACHE_SIZE,
 246         mDNS_Init_DontAdvertiseLocalAddresses,
 247         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 248     if (status == mStatus_NoError) {
 249
 250         // Construct and start the query.
 251
 252         MakeDomainNameFromDNSNameString(&type, gServiceType);
 253         MakeDomainNameFromDNSNameString(&domain, "local.");
 254
 255         status = mDNS_StartBrowse(&mDNSStorage, &question, &type, &domain, mDNSInterface_Any, mDNSfalse, BrowseCallback, NULL);
 256
 257         // Run the platform main event loop until the user types ^C.
 258         // The BrowseCallback routine is responsible for printing
 259         // any results that we find.
 260
 261         if (status == mStatus_NoError) {
 262             fprintf(stderr, "Hit ^C when you're bored waiting for responses.\n");
 263                 ExampleClientEventLoop(&mDNSStorage);
 264             mDNS_StopQuery(&mDNSStorage, &question);
 265                         mDNS_Close(&mDNSStorage);
 266         }
 267     }
 268
 269     if (status == mStatus_NoError) {
 270         result = 0;
 271     } else {
 272         result = 2;
 273     }
 274     if ( (result != 0) || (gMDNSPlatformPosixVerboseLevel > 0) ) {
 275         fprintf(stderr, "%s: Finished with status %ld, result %d\n", gProgramName, status, result);
 276     }
 277
 278     return 0;
 279 }