etc/afpd/afp_mdns.c

   1 /*
   2  * Author:   Lee Essen <lee.essen@nowonline.co.uk>
   3  * Based on: avahi support from Daniel S. Haischt <me@daniel.stefan.haischt.name>
   4  * Purpose:  mdns based Zeroconf support
   5  *
   6  */
   7
   8 #ifdef HAVE_CONFIG_H
   9 #include <config.h>
  10 #endif
  11
  12 #ifdef HAVE_MDNS
  13
  14 #include <unistd.h>
  15 #include <time.h>
  16 #include <pthread.h>
  17 #include <poll.h>
  18
  19 #include <atalk/logger.h>
  20 #include <atalk/util.h>
  21 #include <atalk/dsi.h>
  22 #include <atalk/unicode.h>
  23 #include <atalk/netatalk_conf.h>
  24
  25 #include "afp_zeroconf.h"
  26 #include "afp_mdns.h"
  27
  28 /*
  29  * We'll store all the DNSServiceRef's here so that we can
  30  * deallocate them later
  31  */
  32 static DNSServiceRef   *svc_refs = NULL;
  33 static int             svc_ref_count = 0;
  34 static pthread_t       poller;
  35
  36 /*
  37  * Its easier to use asprintf to set the TXT record values
  38  */
  39 #define TXTRecordPrintf(rec, key, args...) {            \
  40         char *str;                                      \
  41         asprintf(&str, args);                           \
  42         TXTRecordSetValue(rec, key, strlen(str), str);  \
  43         free(str);                                      \
  44     }
  45 #define TXTRecordKeyPrintf(rec, k, var, args...) {      \
  46         char *key, *str;                                \
  47         asprintf(&key, k, var);                         \
  48         asprintf(&str, args);                           \
  49         TXTRecordSetValue(rec, key, strlen(str), str);  \
  50         free(str); free(key);                           \
  51     }
  52
  53 static struct pollfd *fds;
  54
  55 /*
  56  * This is the thread that polls the filehandles
  57  */
  58 static void *polling_thread(void *arg) {
  59     // First we loop through getting the filehandles and adding them to our poll, we
  60     // need to allocate our pollfd's
  61     DNSServiceErrorType error;
  62     fds = calloc(svc_ref_count, sizeof(struct pollfd));
  63     assert(fds);
  64
  65     for(int i=0; i < svc_ref_count; i++) {
  66         int fd = DNSServiceRefSockFD(svc_refs[i]);
  67         fds[i].fd = fd;
  68         fds[i].events = POLLIN;
  69     }
  70
  71     // Now we can poll and process the results...
  72     while(poll(fds, svc_ref_count, -1) > 0) {
  73         for(int i=0; i < svc_ref_count; i++) {
  74             if(fds[i].revents & POLLIN) {
  75                 error = DNSServiceProcessResult(svc_refs[i]);
  76             }
  77         }
  78     }
  79     return(NULL);
  80 }
  81
  82 /*
  83  * This is the callback for the service register function ... actually there isn't a lot
  84  * we can do if we get problems, so we don't really need to do anything other than report
  85  * the issue.
  86  */
  87 static void RegisterReply(DNSServiceRef sdRef, DNSServiceFlags flags, DNSServiceErrorType errorCode,
  88                           const char *name, const char *regtype, const char *domain, void *context)
  89 {
  90     if (errorCode != kDNSServiceErr_NoError) {
  91         LOG(log_error, logtype_afpd, "Failed to register mDNS service: %s%s%s: code=%d",
  92             name, regtype, domain, errorCode);
  93     }
  94 }
  95
  96 /*
  97  * This function unregisters anything we have already
  98  * registered and frees associated memory
  99  */
 100 static void unregister_stuff() {
 101     pthread_cancel(poller);
 102
 103     for (int i = 0; i < svc_ref_count; i++)
 104         close(fds[i].fd);
 105     free(fds);
 106     fds = NULL;
 107
 108     if(svc_refs) {
 109         for(int i=0; i < svc_ref_count; i++) {
 110             DNSServiceRefDeallocate(svc_refs[i]);
 111         }
 112         free(svc_refs);
 113         svc_refs = NULL;
 114         svc_ref_count = 0;
 115     }
 116 }
 117
 118 /*
 119  * This function tries to register the AFP DNS
 120  * SRV service type.
 121  */
 122 static void register_stuff(const AFPObj *obj) {
 123     uint                                        port;
 124     const struct vol                *volume;
 125     DSI                                         *dsi;
 126     char                                        name[MAXINSTANCENAMELEN+1];
 127     DNSServiceErrorType         error;
 128     TXTRecordRef                        txt_adisk;
 129     TXTRecordRef                        txt_devinfo;
 130     char                                        tmpname[256];
 131
 132     // If we had already registered, then we will unregister and re-register
 133     if(svc_refs) unregister_stuff();
 134
 135     /* Register our service, prepare the TXT record */
 136     TXTRecordCreate(&txt_adisk, 0, NULL);
 137     TXTRecordPrintf(&txt_adisk, "sys", "waMa=0,adVF=0x100");
 138
 139     /* Build AFP volumes list */
 140     int i = 0;
 141
 142     for (volume = getvolumes(); volume; volume = volume->v_next) {
 143
 144         if (convert_string(CH_UCS2, CH_UTF8_MAC, volume->v_u8mname, -1, tmpname, 255) <= 0) {
 145             LOG ( log_error, logtype_afpd, "Could not set Zeroconf volume name for TimeMachine");
 146             goto fail;
 147         }
 148
 149         if (volume->v_flags & AFPVOL_TM) {
 150             if (volume->v_uuid) {
 151                 LOG(log_info, logtype_afpd, "Registering volume '%s' with UUID: '%s' for TimeMachine",
 152                     volume->v_localname, volume->v_uuid);
 153                 TXTRecordKeyPrintf(&txt_adisk, "dk%u", i++, "adVN=%s,adVF=0xa1,adVU=%s",
 154                                    tmpname, volume->v_uuid);
 155             } else {
 156                 LOG(log_warning, logtype_afpd, "Registering volume '%s' for TimeMachine. But UUID is invalid.",
 157                     volume->v_localname);
 158                 TXTRecordKeyPrintf(&txt_adisk, "dk%u", i++, "adVN=%s,adVF=0xa1", tmpname);
 159             }
 160         }
 161     }
 162
 163     // Now we can count the configs so we know how many service
 164     // records to allocate
 165     for (dsi = obj->dsi; dsi; dsi = dsi->next) {
 166         svc_ref_count++;                    // AFP_DNS_SERVICE_TYPE
 167         if (i) svc_ref_count++;      // ADISK_SERVICE_TYPE
 168         if (obj->options.mimicmodel) svc_ref_count++;        // DEV_INFO_SERVICE_TYPE
 169     }
 170
 171     // Allocate the memory to store our service refs
 172     svc_refs = calloc(svc_ref_count, sizeof(DNSServiceRef));
 173     assert(svc_ref);
 174     svc_ref_count = 0;
 175
 176     /* AFP server */
 177     for (dsi = obj->dsi; dsi; dsi = dsi->next) {
 178
 179         port = getip_port((struct sockaddr *)&dsi->server);
 180
 181         if (convert_string(obj->options.unixcharset,
 182                            CH_UTF8,
 183                            obj->options.hostname,
 184                            -1,
 185                            name,
 186                            MAXINSTANCENAMELEN) <= 0) {
 187             LOG(log_error, logtype_afpd, "Could not set Zeroconf instance name");
 188             goto fail;
 189         }
 190         if ((dsi->bonjourname = strdup(name)) == NULL) {
 191             LOG(log_error, logtype_afpd, "Could not set Zeroconf instance name");
 192             goto fail;
 193
 194         }
 195         LOG(log_info, logtype_afpd, "Registering server '%s' with Bonjour",
 196             dsi->bonjourname);
 197
 198         error = DNSServiceRegister(&svc_refs[svc_ref_count++],
 199                                    0,               // no flags
 200                                    0,               // all network interfaces
 201                                    dsi->bonjourname,
 202                                    AFP_DNS_SERVICE_TYPE,
 203                                    "",            // default domains
 204                                    NULL,            // default host name
 205                                    htons(port),
 206                                    0,               // length of TXT
 207                                    NULL,            // no TXT
 208                                    RegisterReply,           // callback
 209                                    NULL);       // no context
 210         if(error != kDNSServiceErr_NoError) {
 211             LOG(log_error, logtype_afpd, "Failed to add service: %s, error=%d",
 212                 AFP_DNS_SERVICE_TYPE, error);
 213             goto fail;
 214         }
 215
 216         if(i) {
 217             error = DNSServiceRegister(&svc_refs[svc_ref_count++],
 218                                        0,               // no flags
 219                                        0,               // all network interfaces
 220                                        dsi->bonjourname,
 221                                        ADISK_SERVICE_TYPE,
 222                                        "",            // default domains
 223                                        NULL,            // default host name
 224                                        htons(port),
 225                                        TXTRecordGetLength(&txt_adisk),
 226                                        TXTRecordGetBytesPtr(&txt_adisk),
 227                                        RegisterReply,           // callback
 228                                        NULL);       // no context
 229             if(error != kDNSServiceErr_NoError) {
 230                 LOG(log_error, logtype_afpd, "Failed to add service: %s, error=%d",
 231                     ADISK_SERVICE_TYPE, error);
 232                 goto fail;
 233             }
 234         }
 235
 236         if (obj->options.mimicmodel) {
 237             LOG(log_info, logtype_afpd, "Registering server '%s' with model '%s'",
 238                 dsi->bonjourname, obj->options.mimicmodel);
 239             TXTRecordCreate(&txt_devinfo, 0, NULL);
 240             TXTRecordPrintf(&txt_devinfo, "model", obj->options.mimicmodel);
 241             error = DNSServiceRegister(&svc_refs[svc_ref_count++],
 242                                        0,               // no flags
 243                                        0,               // all network interfaces
 244                                        dsi->bonjourname,
 245                                        DEV_INFO_SERVICE_TYPE,
 246                                        "",            // default domains
 247                                        NULL,            // default host name
 248                                        /*
 249                                         * We would probably use port 0 zero, but we can't, from man DNSServiceRegister:
 250                                         *   "A value of 0 for a port is passed to register placeholder services.
 251                                         *    Place holder services are not found  when browsing, but other
 252                                         *    clients cannot register with the same name as the placeholder service."
 253                                         * We therefor use port 9 which is used by the adisk service type.
 254                                         */
 255                                        htons(9),
 256                                        TXTRecordGetLength(&txt_devinfo),
 257                                        TXTRecordGetBytesPtr(&txt_devinfo),
 258                                        RegisterReply,           // callback
 259                                        NULL);       // no context
 260             TXTRecordDeallocate(&txt_devinfo);
 261             if(error != kDNSServiceErr_NoError) {
 262                 LOG(log_error, logtype_afpd, "Failed to add service: %s, error=%d",
 263                     DEV_INFO_SERVICE_TYPE, error);
 264                 goto fail;
 265             }
 266         } /* if (config->obj.options.mimicmodel) */
 267     }   /* for config*/
 268
 269         /*
 270          * Now we can create the thread that will poll for the results
 271          * and handle the calling of the callbacks
 272          */
 273     if(pthread_create(&poller, NULL, polling_thread, NULL) != 0) {
 274         LOG(log_error, logtype_afpd, "Unable to start mDNS polling thread");
 275         goto fail;
 276     }
 277
 278 fail:
 279     TXTRecordDeallocate(&txt_adisk);
 280     return;
 281 }
 282
 283 /************************************************************************
 284  * Public funcions
 285  ************************************************************************/
 286
 287 /*
 288  * Tries to setup the Zeroconf thread and any
 289  * neccessary config setting.
 290  */
 291 void md_zeroconf_register(const AFPObj *obj) {
 292     int error;
 293
 294     register_stuff(obj);
 295     return;
 296 }
 297
 298 /*
 299  * Tries to shutdown this loop impl.
 300  * Call this function from inside this thread.
 301  */
 302 int md_zeroconf_unregister() {
 303     unregister_stuff();
 304     return 0;
 305 }
 306
 307 #endif /* USE_MDNS */
 308