mDNSPosix/ProxyResponder.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 #include <stdio.h>              // For printf()
  19 #include <stdlib.h>             // For exit() etc.
  20 #include <string.h>             // For strlen() etc.
  21 #include <unistd.h>             // For select()
  22 #include <signal.h>             // For SIGINT, SIGTERM
  23 #include <errno.h>              // For errno, EINTR
  24 #include <netinet/in.h>         // For INADDR_NONE
  25 #include <arpa/inet.h>          // For inet_addr()
  26 #include <netdb.h>              // For gethostbyname()
  27
  28 #include "mDNSEmbeddedAPI.h"    // Defines the interface to the client layer above
  29 #include "mDNSPosix.h"          // Defines the specific types needed to run mDNS on this platform
  30 #include "ExampleClientApp.h"
  31
  32 // Compatibility workaround: Solaris 2.5 has no INADDR_NONE
  33 #ifndef INADDR_NONE
  34 #define INADDR_NONE (mDNSu32)0xffffffff
  35 #endif
  36
  37 //*************************************************************************************************************
  38 // Globals
  39 static mDNS mDNSStorage;       // mDNS core uses this to store its globals
  40 static mDNS_PlatformSupport PlatformStorage;  // Stores this platform's globals
  41 mDNSexport const char ProgramName[] = "mDNSProxyResponderPosix";
  42
  43 //*************************************************************************************************************
  44 // Proxy Host Registration
  45
  46 typedef struct
  47 {
  48     mDNSv4Addr ip;
  49     domainlabel hostlabel;      // Conforms to standard DNS letter-digit-hyphen host name rules
  50     AuthRecord RR_A;        // 'A' (address) record for our ".local" name
  51     AuthRecord RR_PTR;      // PTR (reverse lookup) record
  52 } ProxyHost;
  53
  54 mDNSlocal void HostNameCallback(mDNS *const m, AuthRecord *const rr, mStatus result)
  55 {
  56     ProxyHost *f = (ProxyHost*)rr->RecordContext;
  57     if (result == mStatus_NoError)
  58         debugf("Host name successfully registered: %##s", rr->resrec.name->c);
  59     else
  60     {
  61         debugf("Host name conflict for %##s", rr->resrec.name->c);
  62         mDNS_Deregister(m, &f->RR_A);
  63         mDNS_Deregister(m, &f->RR_PTR);
  64         exit(-1);
  65     }
  66 }
  67
  68 mDNSlocal mStatus mDNS_RegisterProxyHost(mDNS *m, ProxyHost *p)
  69 {
  70     char buffer[32];
  71
  72     mDNS_SetupResourceRecord(&p->RR_A,   mDNSNULL, mDNSInterface_Any, kDNSType_A,   60, kDNSRecordTypeUnique,      AuthRecordAny, HostNameCallback, p);
  73     mDNS_SetupResourceRecord(&p->RR_PTR, mDNSNULL, mDNSInterface_Any, kDNSType_PTR, 60, kDNSRecordTypeKnownUnique, AuthRecordAny, HostNameCallback, p);
  74
  75     p->RR_A.namestorage.c[0] = 0;
  76     AppendDomainLabel(&p->RR_A.namestorage, &p->hostlabel);
  77     AppendLiteralLabelString(&p->RR_A.namestorage, "local");
  78
  79     // Note: This is reverse order compared to a normal dotted-decimal IP address, so we can't use our customary "%.4a" format code
  80     mDNS_snprintf(buffer, sizeof(buffer), "%d.%d.%d.%d.in-addr.arpa.", p->ip.b[3], p->ip.b[2], p->ip.b[1], p->ip.b[0]);
  81     MakeDomainNameFromDNSNameString(&p->RR_PTR.namestorage, buffer);
  82     p->RR_PTR.ForceMCast = mDNStrue; // This PTR points to our dot-local name, so don't ever try to write it into a uDNS server
  83
  84     p->RR_A.resrec.rdata->u.ipv4 = p->ip;
  85     AssignDomainName(&p->RR_PTR.resrec.rdata->u.name, p->RR_A.resrec.name);
  86
  87     mDNS_Register(m, &p->RR_A);
  88     mDNS_Register(m, &p->RR_PTR);
  89
  90     debugf("Made Proxy Host Records for %##s", p->RR_A.resrec.name->c);
  91
  92     return(mStatus_NoError);
  93 }
  94
  95 //*************************************************************************************************************
  96 // Service Registration
  97
  98 // This sample ServiceCallback just calls mDNS_RenameAndReregisterService to automatically pick a new
  99 // unique name for the service. For a device such as a printer, this may be appropriate.
 100 // For a device with a user interface, and a screen, and a keyboard, the appropriate
 101 // response may be to prompt the user and ask them to choose a new name for the service.
 102 mDNSlocal void ServiceCallback(mDNS *const m, ServiceRecordSet *const sr, mStatus result)
 103 {
 104     switch (result)
 105     {
 106     case mStatus_NoError:      debugf("Callback: %##s Name Registered",    sr->RR_SRV.resrec.name->c); break;
 107     case mStatus_NameConflict: debugf("Callback: %##s Name Conflict",      sr->RR_SRV.resrec.name->c); break;
 108     case mStatus_MemFree:      debugf("Callback: %##s Memory Free",        sr->RR_SRV.resrec.name->c); break;
 109     default:                   debugf("Callback: %##s Unknown Result %ld", sr->RR_SRV.resrec.name->c, result); break;
 110     }
 111
 112     if (result == mStatus_NoError)
 113     {
 114         char buffer[MAX_ESCAPED_DOMAIN_NAME];
 115         ConvertDomainNameToCString(sr->RR_SRV.resrec.name, buffer);
 116         printf("Service %s now registered and active\n", buffer);
 117     }
 118
 119     if (result == mStatus_NameConflict)
 120     {
 121         char buffer1[MAX_ESCAPED_DOMAIN_NAME], buffer2[MAX_ESCAPED_DOMAIN_NAME];
 122         ConvertDomainNameToCString(sr->RR_SRV.resrec.name, buffer1);
 123         mDNS_RenameAndReregisterService(m, sr, mDNSNULL);
 124         ConvertDomainNameToCString(sr->RR_SRV.resrec.name, buffer2);
 125         printf("Name Conflict! %s renamed as %s\n", buffer1, buffer2);
 126     }
 127 }
 128
 129 // RegisterService() is a simple wrapper function which takes C string
 130 // parameters, converts them to domainname parameters, and calls mDNS_RegisterService()
 131 mDNSlocal void RegisterService(mDNS *m, ServiceRecordSet *recordset,
 132                                const char name[], const char type[], const char domain[],
 133                                const domainname *host, mDNSu16 PortAsNumber, int argc, char **argv)
 134 {
 135     domainlabel n;
 136     domainname t, d;
 137     unsigned char txtbuffer[1024], *bptr = txtbuffer;
 138     char buffer[MAX_ESCAPED_DOMAIN_NAME];
 139
 140     MakeDomainLabelFromLiteralString(&n, name);
 141     MakeDomainNameFromDNSNameString(&t, type);
 142     MakeDomainNameFromDNSNameString(&d, domain);
 143     while (argc)
 144     {
 145         int len = strlen(argv[0]);
 146         if (len > 255 || bptr + 1 + len >= txtbuffer + sizeof(txtbuffer)) break;
 147         printf("STR: %s\n", argv[0]);
 148         bptr[0] = len;
 149         strcpy((char*)(bptr+1), argv[0]);
 150         bptr += 1 + len;
 151         argc--;
 152         argv++;
 153     }
 154
 155     mDNS_RegisterService(m, recordset,
 156                          &n, &t, &d, // Name, type, domain
 157                          host, mDNSOpaque16fromIntVal(PortAsNumber),
 158                          txtbuffer, bptr-txtbuffer, // TXT data, length
 159                          mDNSNULL, 0, // Subtypes
 160                          mDNSInterface_Any, // Interface ID
 161                          ServiceCallback, mDNSNULL, 0); // Callback, context, flags
 162
 163     ConvertDomainNameToCString(recordset->RR_SRV.resrec.name, buffer);
 164     printf("Made Service Records for %s\n", buffer);
 165 }
 166
 167 //*************************************************************************************************************
 168 // Service non-existence assertion
 169 // (claiming a service name without actually providing a service at that name, to prevent anyone else using that name)
 170 // This is useful to avoid confusion between similar services
 171 // e.g. A printer that implements IPP printing service using the name "My Printer", but doesn't implement LPR service,
 172 // should also claim the LPR service name "My Printer" to stop a different printer offering LPR service under the same name,
 173 // since it would be confusing to users to have two equivalent services with the same name.
 174
 175 mDNSlocal void NoSuchServiceCallback(mDNS *const m, AuthRecord *const rr, mStatus result)
 176 {
 177     const domainname *proxyhostname = (const domainname *)rr->RecordContext;
 178     switch (result)
 179     {
 180     case mStatus_NoError:      debugf("Callback: %##s Name Registered",    rr->resrec.name->c); break;
 181     case mStatus_NameConflict: debugf("Callback: %##s Name Conflict",      rr->resrec.name->c); break;
 182     case mStatus_MemFree:      debugf("Callback: %##s Memory Free",        rr->resrec.name->c); break;
 183     default:                   debugf("Callback: %##s Unknown Result %ld", rr->resrec.name->c, result); break;
 184     }
 185
 186     if (result == mStatus_NoError)
 187     {
 188         char buffer[MAX_ESCAPED_DOMAIN_NAME];
 189         ConvertDomainNameToCString(rr->resrec.name, buffer);
 190         printf("Non-existence assertion %s now registered and active\n", buffer);
 191     }
 192
 193     if (result == mStatus_NameConflict)
 194     {
 195         domainlabel n;
 196         domainname t, d;
 197         char buffer1[MAX_ESCAPED_DOMAIN_NAME], buffer2[MAX_ESCAPED_DOMAIN_NAME];
 198         ConvertDomainNameToCString(rr->resrec.name, buffer1);
 199         DeconstructServiceName(rr->resrec.name, &n, &t, &d);
 200         IncrementLabelSuffix(&n, mDNStrue);
 201         mDNS_RegisterNoSuchService(m, rr, &n, &t, &d, proxyhostname, mDNSInterface_Any, NoSuchServiceCallback, mDNSNULL, 0);
 202         ConvertDomainNameToCString(rr->resrec.name, buffer2);
 203         printf("Name Conflict! %s renamed as %s\n", buffer1, buffer2);
 204     }
 205 }
 206
 207 mDNSlocal void RegisterNoSuchService(mDNS *m, AuthRecord *const rr, domainname *proxyhostname,
 208                                      const char name[], const char type[], const char domain[])
 209 {
 210     domainlabel n;
 211     domainname t, d;
 212     char buffer[MAX_ESCAPED_DOMAIN_NAME];
 213     MakeDomainLabelFromLiteralString(&n, name);
 214     MakeDomainNameFromDNSNameString(&t, type);
 215     MakeDomainNameFromDNSNameString(&d, domain);
 216     mDNS_RegisterNoSuchService(m, rr, &n, &t, &d, proxyhostname, mDNSInterface_Any, NoSuchServiceCallback, proxyhostname, 0);
 217     ConvertDomainNameToCString(rr->resrec.name, buffer);
 218     printf("Made Non-existence Record for %s\n", buffer);
 219 }
 220
 221 //*************************************************************************************************************
 222 // Main
 223
 224 mDNSexport int main(int argc, char **argv)
 225 {
 226     mStatus status;
 227     sigset_t signals;
 228
 229     if (argc < 3) goto usage;
 230
 231     status = mDNS_Init(&mDNSStorage, &PlatformStorage,
 232                        mDNS_Init_NoCache, mDNS_Init_ZeroCacheSize,
 233                        mDNS_Init_DontAdvertiseLocalAddresses,
 234                        mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 235     if (status) { fprintf(stderr, "Daemon start: mDNS_Init failed %d\n", (int)status); return(status); }
 236
 237     mDNSPosixListenForSignalInEventLoop(SIGINT);
 238     mDNSPosixListenForSignalInEventLoop(SIGTERM);
 239
 240     if (!strcmp(argv[1], "-"))
 241     {
 242         domainname proxyhostname;
 243         AuthRecord proxyrecord;
 244         if (argc < 5) goto usage;
 245         proxyhostname.c[0] = 0;
 246         AppendLiteralLabelString(&proxyhostname, argv[2]);
 247         AppendLiteralLabelString(&proxyhostname, "local");
 248         RegisterNoSuchService(&mDNSStorage, &proxyrecord, &proxyhostname, argv[3], argv[4], "local.");
 249     }
 250     else
 251     {
 252         ProxyHost proxyhost;
 253         ServiceRecordSet proxyservice;
 254
 255         proxyhost.ip.NotAnInteger = inet_addr(argv[1]);
 256         if (proxyhost.ip.NotAnInteger == INADDR_NONE)   // INADDR_NONE is 0xFFFFFFFF
 257         {
 258             struct hostent *h = gethostbyname(argv[1]);
 259             if (h) proxyhost.ip.NotAnInteger = *(long*)h->h_addr;
 260         }
 261         if (proxyhost.ip.NotAnInteger == INADDR_NONE)   // INADDR_NONE is 0xFFFFFFFF
 262         {
 263             fprintf(stderr, "%s is not valid host address\n", argv[1]);
 264             return(-1);
 265         }
 266
 267         MakeDomainLabelFromLiteralString(&proxyhost.hostlabel, argv[2]);
 268
 269         mDNS_RegisterProxyHost(&mDNSStorage, &proxyhost);
 270
 271         if (argc >=6)
 272             RegisterService(&mDNSStorage, &proxyservice, argv[3], argv[4], "local.",
 273                             proxyhost.RR_A.resrec.name, atoi(argv[5]), argc-6, &argv[6]);
 274     }
 275
 276     do
 277     {
 278         struct timeval timeout = { 0x3FFFFFFF, 0 };     // wait until SIGINT or SIGTERM
 279         mDNSBool gotSomething;
 280         mDNSPosixRunEventLoopOnce(&mDNSStorage, &timeout, &signals, &gotSomething);
 281     }
 282     while ( !( sigismember( &signals, SIGINT) || sigismember( &signals, SIGTERM)));
 283
 284     mDNS_Close(&mDNSStorage);
 285
 286     return(0);
 287
 288 usage:
 289     fprintf(stderr, "%s ip hostlabel [srvname srvtype port txt [txt ...]]\n", argv[0]);
 290     fprintf(stderr, "ip        Real IP address (or valid host name) of the host where the service actually resides\n");
 291     fprintf(stderr, "hostlabel First label of the dot-local host name to create for this host, e.g. \"foo\" for \"foo.local.\"\n");
 292     fprintf(stderr, "srvname   Descriptive name of service, e.g. \"Stuart's Ink Jet Printer\"\n");
 293     fprintf(stderr, "srvtype   IANA service type, e.g. \"_ipp._tcp\" or \"_ssh._tcp\", etc.\n");
 294     fprintf(stderr, "port      Port number where the service resides (1-65535)\n");
 295     fprintf(stderr, "txt       Additional name/value pairs specified in service definition, e.g. \"pdl=application/postscript\"\n");
 296     fprintf(stderr, "e.g. %s 169.254.12.34 thehost                                (just create a dot-local host name)\n", argv[0]);
 297     fprintf(stderr, "or   %s 169.254.12.34 thehost \"My Printer\" _printer._tcp. 515 rp=lpt1 pdl=application/postscript\n", argv[0]);
 298     fprintf(stderr, "or   %s -             thehost \"My Printer\" _printer._tcp.           (assertion of non-existence)\n", argv[0]);
 299     return(-1);
 300 }