lisp/net/zeroconf.el

   1 ;;; zeroconf.el --- Service browser using Avahi.
   2
   3 ;; Copyright (C) 2008-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: Michael Albinus <michael.albinus@gmx.de>
   6 ;; Keywords: comm, hardware
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; This package provides an interface to the Avahi, the zeroconf
  26 ;; daemon under GNU/Linux.  The communication mean with Avahi is
  27 ;; D-Bus.
  28
  29 ;; In order to activate this package, you must add the following code
  30 ;; into your .emacs:
  31
  32 ;;   (require 'zeroconf)
  33 ;;   (zeroconf-init "dns-sd.org")
  34
  35 ;; "dns-sd.org" is an example the domain you wish to resolve services
  36 ;; for.  It can also be nil or "", which means the default local
  37 ;; domain "local".
  38
  39 ;; The `zeroconf-init' function installs several handlers, which are
  40 ;; activated by D-Bus signals sent from the Avahi daemon.
  41 ;; Immediately, when a service is added or removed in the domain, a
  42 ;; corresponding handler in Emacs is called.
  43
  44 ;; Service Discovery
  45 ;; -----------------
  46
  47 ;; The main purpose of zeroconf is service discovery.  This means,
  48 ;; that services are detected as soon as they appear or disappear in a
  49 ;; given domain.  A service is offered by a network device.  It is
  50 ;; assigned to a service type.
  51
  52 ;; In order to see all offered service types of the initialized
  53 ;; domain, you can call
  54
  55 ;;   (zeroconf-list-service-types)
  56
  57 ;; Service types are described at <http://www.dns-sd.org/ServiceTypes.html>.
  58 ;; Detected services for a given service type, let's say "_ipp._tcp",
  59 ;; are listed by
  60
  61 ;;   (zeroconf-list-services "_ipp._tcp")
  62
  63 ;; It is possible to register an own handler (function) to be called
  64 ;; when a service has been added or removed in the domain.  The
  65 ;; service type "_ipp._tcp" is used for printer services supporting
  66 ;; the Internet Printing Protocol.
  67
  68 ;;   (defun my-add-printer (service)
  69 ;;     (message "Printer `%s' detected" (zeroconf-service-name service)))
  70
  71 ;;   (defun my-remove-printer (service)
  72 ;;     (message "Printer `%s' removed" (zeroconf-service-name service)))
  73
  74 ;;   (zeroconf-service-add-hook "_ipp._tcp" :new     'my-add-printer)
  75 ;;   (zeroconf-service-add-hook "_ipp._tcp" :removed 'my-remove-printer)
  76
  77 ;; There are several functions returning information about a service,
  78 ;; see the doc string of `zeroconf-service-add-hook'.
  79
  80 ;; Service Publishing
  81 ;; ------------------
  82
  83 ;; The function `zeroconf-publish-service' publishes a new service to
  84 ;; the Avahi daemon.  Although the domain, where to the service is
  85 ;; published, can be specified by this function, it is usually the
  86 ;; default domain "local" (also written as nil or "").
  87
  88 ;;   (zeroconf-publish-service
  89 ;;    "Example service" ;; Service name.
  90 ;;    "_example._tcp"   ;; Service type.
  91 ;;    nil               ;; Default domain ("local").
  92 ;;    nil               ;; Default host (concat (getenv "HOST") ".local").
  93 ;;    111               ;; Port number of the host, the service is offered.
  94 ;;    "1.2.3.4"         ;; IPv4 address of the host.
  95 ;;    '("version=1.0"   ;; TXT fields describing the service.
  96 ;;      "abc=456"))
  97
  98 ;; The lifetime of a published service is the lifetime of Emacs.
  99
 100 ;;; Code:
 101
 102 ;;  Pacify byte-compiler.  D-Bus support in the Emacs core can be
 103 ;; disabled with configuration option "--without-dbus".  Declare used
 104 ;; subroutines and variables of `dbus' therefore.
 105 (eval-when-compile
 106   (require 'cl))
 107
 108 (declare-function dbus-call-method "dbusbind.c")
 109 (declare-function dbus-register-signal "dbusbind.c")
 110 (defvar dbus-debug)
 111
 112 (require 'dbus)
 113
 114 (defvar zeroconf-debug nil
 115   "Write messages during service discovery")
 116
 117 (defconst zeroconf-service-avahi "org.freedesktop.Avahi"
 118   "The D-Bus name used to talk to Avahi.")
 119
 120 (defconst zeroconf-path-avahi "/"
 121   "The D-Bus root object path used to talk to Avahi.")
 122
 123 (defvar zeroconf-path-avahi-service-type-browser nil
 124   "The D-Bus object path used to talk to the Avahi service type browser.")
 125
 126 (defvar zeroconf-path-avahi-service-browser-hash (make-hash-table :test 'equal)
 127   "The D-Bus object paths used to talk to the Avahi service browser.")
 128
 129 (defvar zeroconf-path-avahi-service-resolver-hash (make-hash-table :test 'equal)
 130   "The D-Bus object paths used to talk to the Avahi service resolver.")
 131
 132 ;; Methods: "Free", "Commit", "Reset", "GetState", "IsEmpty",
 133 ;; "AddService", "AddServiceSubtype", "UpdateServiceTxt", "AddAddress"
 134 ;; and "AddRecord".
 135 ;; Signals: "StateChanged".
 136 (defconst zeroconf-interface-avahi-entry-group
 137   (concat zeroconf-service-avahi ".EntryGroup")
 138   "The D-Bus entry group interface exported by Avahi.")
 139
 140 ;; Methods: "GetVersionString", "GetAPIVersion", "GetHostName",
 141 ;; "SetHostName", "GetHostNameFqdn", "GetDomainName",
 142 ;; "IsNSSSupportAvailable", "GetState", "GetLocalServiceCookie",
 143 ;; "GetAlternativeHostName", "GetAlternativeServiceName",
 144 ;; "GetNetworkInterfaceNameByIndex", "GetNetworkInterfaceIndexByName",
 145 ;; "ResolveHostName", "ResolveAddress", "ResolveService",
 146 ;; "EntryGroupNew", "DomainBrowserNew", "ServiceTypeBrowserNew",
 147 ;; "ServiceBrowserNew", "ServiceResolverNew", "HostNameResolverNew",
 148 ;; "AddressResolverNew" and "RecordBrowserNew".
 149 ;; Signals: "StateChanged".
 150 (defconst zeroconf-interface-avahi-server
 151   (concat zeroconf-service-avahi ".Server")
 152   "The D-Bus server interface exported by Avahi.")
 153
 154 ;; Methods: "Free".
 155 ;; Signals: "ItemNew", "ItemRemove", "CacheExhausted", "AllForNow" and
 156 ;; "Failure".
 157 (defconst zeroconf-interface-avahi-service-type-browser
 158   (concat zeroconf-service-avahi ".ServiceTypeBrowser")
 159   "The D-Bus service type browser interface exported by Avahi.")
 160
 161 ;; Methods: "Free".
 162 ;; Signals: "ItemNew", "ItemRemove", "CacheExhausted", "AllForNow" and
 163 ;; "Failure".
 164 (defconst zeroconf-interface-avahi-service-browser
 165   (concat zeroconf-service-avahi ".ServiceBrowser")
 166   "The D-Bus service browser interface exported by Avahi.")
 167
 168 ;; Methods: "Free".
 169 ;; Available signals are "Found" and "Failure".
 170 (defconst zeroconf-interface-avahi-service-resolver
 171   (concat zeroconf-service-avahi ".ServiceResolver")
 172   "The D-Bus service resolver interface exported by Avahi.")
 173
 174 (defconst zeroconf-avahi-interface-unspec -1
 175   "Wildcard Avahi interface spec.")
 176
 177 (defconst zeroconf-avahi-protocol-unspec -1
 178   "Wildcard Avahi protocol spec.")
 179
 180 (defconst zeroconf-avahi-protocol-inet4 0
 181   "Avahi INET4 address protocol family.")
 182
 183 (defconst zeroconf-avahi-protocol-inet6 1
 184   "Avahi INET6 address protocol family.")
 185
 186 (defconst zeroconf-avahi-domain-unspec ""
 187   "Empty Avahi domain.")
 188
 189 (defvar zeroconf-avahi-current-domain zeroconf-avahi-domain-unspec
 190   "Domain name services are resolved for.")
 191
 192 (defconst zeroconf-avahi-flags-unspec 0
 193   "No Avahi flags.")
 194
 195 \f
 196 ;;; Services retrieval.
 197
 198 (defvar zeroconf-services-hash (make-hash-table :test 'equal)
 199   "Hash table of discovered Avahi services.
 200
 201 The key of an entry is the concatenation of the service name and
 202 service type of a discovered service.  The value is the service
 203 itself.  The format of a service is
 204
 205   \(INTERFACE PROTOCOL NAME TYPE DOMAIN FLAGS\)
 206
 207 The INTERFACE is a number, which represents the network interface
 208 the service is located at.  The corresponding network interface
 209 name, like \"eth0\", can be retrieved with the function
 210 `zeroconf-get-interface-name'.
 211
 212 PROTOCOL describes the used network protocol family the service
 213 can be accessed.  `zeroconf-avahi-protocol-inet4' means INET4,
 214 `zeroconf-avahi-protocol-inet6' means INET6.  An unspecified
 215 protocol family is coded with `zeroconf-avahi-protocol-unspec'.
 216
 217 NAME is the string the service is known at Avahi.  A service can
 218 be known under the same name for different service types.
 219
 220 Each TYPE stands for a discovered service type of Avahi.  The
 221 format is described in RFC 2782.  It is of the form
 222
 223   \"_APPLICATION-PROTOCOL._TRANSPORT-PROTOCOL\".
 224
 225 TRANSPORT-PROTOCOL must be either \"tcp\" or \"udp\".
 226 APPLICATION-PROTOCOL must be a protocol name as specified in URL
 227 `http://www.dns-sd.org/ServiceTypes.html'.  Typical service types
 228 are \"_workstation._tcp\" or \"_printer._tcp\".
 229
 230 DOMAIN is the domain name the service is registered in, like \"local\".
 231
 232 FLAGS, an integer, is used inside Avahi.  When publishing a
 233 service (see `zeroconf-publish-service', the flag 0 is used.")
 234
 235 (defvar zeroconf-resolved-services-hash (make-hash-table :test 'equal)
 236   "Hash table of resolved Avahi services.
 237 The key of an entry is the concatenation of the service name and
 238 service type of a resolved service.  The value is the service
 239 itself.  The format of a service is
 240
 241   \(INTERFACE PROTOCOL NAME TYPE DOMAIN HOST APROTOCOL ADDRESS PORT TXT FLAGS\)
 242
 243 INTERFACE, PROTOCOL, NAME, TYPE, DOMAIN and FLAGS have the same
 244 meaning as in `zeroconf-services-hash'.
 245
 246 HOST is the host name the service is registered.  It is a fully
 247 qualified name, i.e., it contains DOMAIN.
 248
 249 APROTOCOL stands for the network protocol family ADDRESS is
 250 encoded (`zeroconf-avahi-protocol-inet4' means INET4,
 251 `zeroconf-avahi-protocol-inet6' means INET6).  It can be
 252 different from PROTOCOL, when an address resolution has been
 253 requested for another protocol family but the default one.
 254
 255 ADDRESS is the service address, encoded according to the
 256 APROTOCOL network protocol family.  PORT is the corresponding
 257 port the service can be reached on ADDRESS.
 258
 259 TXT is an array of strings, describing additional attributes of
 260 the service.  Usually, every string is a key=value pair.  The
 261 supported keys depend on the service type.")
 262
 263 (defun zeroconf-list-service-names ()
 264   "Returns all discovered Avahi service names as list."
 265   (let (result)
 266     (maphash
 267      (lambda (key value) (add-to-list 'result (zeroconf-service-name value)))
 268      zeroconf-services-hash)
 269     result))
 270
 271 (defun zeroconf-list-service-types ()
 272   "Returns all discovered Avahi service types as list."
 273   (let (result)
 274     (maphash
 275      (lambda (key value) (add-to-list 'result (zeroconf-service-type value)))
 276      zeroconf-services-hash)
 277     result))
 278
 279 (defun zeroconf-list-services (type)
 280   "Returns all discovered Avahi services for a given service type TYPE.
 281 The service type is one of the returned values of
 282 `zeroconf-list-service-types'.  The return value is a list
 283 \(SERVICE1 SERVICE2 ...\).  See `zeroconf-services-hash' for the
 284 format of SERVICE."
 285   (let (result)
 286     (maphash
 287      (lambda (key value)
 288        (when (equal type (zeroconf-service-type value))
 289          (add-to-list 'result value)))
 290      zeroconf-services-hash)
 291     result))
 292
 293 (defvar zeroconf-service-added-hooks-hash (make-hash-table :test 'equal)
 294   "Hash table of hooks for newly added services.
 295 The key of an entry is a service type.")
 296
 297 (defvar zeroconf-service-removed-hooks-hash (make-hash-table :test 'equal)
 298   "Hash table of hooks for removed services.
 299 The key of an entry is a service type.")
 300
 301 (defun zeroconf-service-add-hook (type event function)
 302   "Add FUNCTION to the hook of service type TYPE.
 303
 304 EVENT must be either :new or :removed, indicating whether
 305 FUNCTION shall be called when a new service has been newly
 306 detected, or removed.
 307
 308 FUNCTION must accept one argument SERVICE, which identifies the
 309 new service.  Initially, when EVENT is :new, FUNCTION is called
 310 for all already detected services of service type TYPE.
 311
 312 The attributes of SERVICE can be retrieved via the functions
 313
 314   `zeroconf-service-interface'
 315   `zeroconf-service-protocol'
 316   `zeroconf-service-name'
 317   `zeroconf-service-type'
 318   `zeroconf-service-domain'
 319   `zeroconf-service-flags'
 320   `zeroconf-service-host'
 321   `zeroconf-service-aprotocol'
 322   `zeroconf-service-address'
 323   `zeroconf-service-port'
 324   `zeroconf-service-txt'"
 325
 326   (cond
 327    ((equal event :new)
 328     (let ((l-hook (gethash type zeroconf-service-added-hooks-hash nil)))
 329       (add-hook 'l-hook function)
 330       (puthash type l-hook zeroconf-service-added-hooks-hash)
 331       (dolist (service (zeroconf-list-services type))
 332         (funcall function service))))
 333    ((equal event :removed)
 334     (let ((l-hook (gethash type zeroconf-service-removed-hooks-hash nil)))
 335       (add-hook 'l-hook function)
 336       (puthash type l-hook zeroconf-service-removed-hooks-hash)))
 337    (t (error "EVENT must be either `:new' or `:removed'"))))
 338
 339 (defun zeroconf-service-remove-hook (type event function)
 340   "Remove FUNCTION from the hook of service type TYPE.
 341
 342 EVENT must be either :new or :removed and has to match the event
 343 type used when registering FUNCTION."
 344   (let* ((table (cond
 345                  ((equal event :new)
 346                   zeroconf-service-added-hooks-hash)
 347                  ((equal event :removed)
 348                   zeroconf-service-removed-hooks-hash)
 349                  (t (error "EVENT must be either `:new' or `:removed'"))))
 350          (l-hook (gethash type table nil)))
 351     (remove-hook 'l-hook function)
 352     (if l-hook
 353         (puthash type l-hook table)
 354       (remhash type table))))
 355
 356 (defun zeroconf-get-host ()
 357   "Returns the local host name as string."
 358   (dbus-call-method
 359    :system zeroconf-service-avahi zeroconf-path-avahi
 360    zeroconf-interface-avahi-server "GetHostName"))
 361
 362 (defun zeroconf-get-domain ()
 363   "Returns the domain name as string."
 364   (dbus-call-method
 365    :system zeroconf-service-avahi zeroconf-path-avahi
 366    zeroconf-interface-avahi-server "GetDomainName"))
 367
 368 (defun zeroconf-get-host-domain ()
 369   "Returns the local host name FQDN as string."
 370   (dbus-call-method
 371    :system zeroconf-service-avahi zeroconf-path-avahi
 372    zeroconf-interface-avahi-server "GetHostNameFqdn"))
 373
 374 (defun zeroconf-get-interface-name (number)
 375   "Return the interface name of internal interface NUMBER."
 376   (dbus-call-method
 377    :system zeroconf-service-avahi zeroconf-path-avahi
 378    zeroconf-interface-avahi-server "GetNetworkInterfaceNameByIndex"
 379    :int32 number))
 380
 381 (defun zeroconf-get-interface-number (name)
 382   "Return the internal interface number of interface NAME."
 383   (dbus-call-method
 384    :system zeroconf-service-avahi zeroconf-path-avahi
 385    zeroconf-interface-avahi-server "GetNetworkInterfaceIndexByName"
 386    name))
 387
 388 (defun zeroconf-get-service (name type)
 389   "Return the service description of service NAME as list.
 390 NAME must be a string.  The service must be of service type
 391 TYPE. The resulting list has the format
 392
 393   \(INTERFACE PROTOCOL NAME TYPE DOMAIN FLAGS\)."
 394   ;; Due to the service browser, all known services are kept in
 395   ;; `zeroconf-services-hash'.
 396   (gethash (concat name "/" type) zeroconf-services-hash nil))
 397
 398 (defun zeroconf-resolve-service (service)
 399   "Return all service attributes SERVICE as list.
 400 NAME must be a string.  The service must be of service type
 401 TYPE. The resulting list has the format
 402
 403   \(INTERFACE PROTOCOL NAME TYPE DOMAIN HOST APROTOCOL ADDRESS PORT TXT FLAGS\)."
 404   (let* ((name (zeroconf-service-name service))
 405          (type (zeroconf-service-type service))
 406          (key (concat name "/" type)))
 407
 408     (or
 409      ;; Check whether we know this service already.
 410      (gethash key zeroconf-resolved-services-hash nil)
 411
 412      ;; Resolve the service.  We don't propagate D-Bus errors.
 413      (dbus-ignore-errors
 414        (let* ((result
 415                (dbus-call-method
 416                 :system zeroconf-service-avahi zeroconf-path-avahi
 417                 zeroconf-interface-avahi-server "ResolveService"
 418                 zeroconf-avahi-interface-unspec
 419                 zeroconf-avahi-protocol-unspec
 420                 name type
 421                 zeroconf-avahi-current-domain
 422                 zeroconf-avahi-protocol-unspec
 423                 zeroconf-avahi-flags-unspec))
 424               (elt (nth 9 result))) ;; TXT.
 425          ;; The TXT field has the signature "aay".  Transform to "as".
 426          (while elt
 427            (setcar elt (dbus-byte-array-to-string (car elt)))
 428            (setq elt (cdr elt)))
 429
 430          (when nil ;; We discard it, no use so far.
 431          ;; Register a service resolver.
 432          (let ((object-path (zeroconf-register-service-resolver name type)))
 433            ;; Register the signals.
 434            (dolist (member '("Found" "Failure"))
 435              (dbus-register-signal
 436               :system zeroconf-service-avahi object-path
 437               zeroconf-interface-avahi-service-resolver member
 438               'zeroconf-service-resolver-handler)))
 439          )
 440
 441          ;; Return the resolved service.
 442          (puthash key result zeroconf-resolved-services-hash))))))
 443
 444 (defun zeroconf-service-interface (service)
 445   "Return the internal interface number of SERVICE."
 446   (nth 0 service))
 447
 448 (defun zeroconf-service-protocol (service)
 449   "Return the protocol number of SERVICE."
 450   (nth 1 service))
 451
 452 (defun zeroconf-service-name (service)
 453   "Return the service name of SERVICE."
 454   (nth 2 service))
 455
 456 (defun zeroconf-service-type (service)
 457   "Return the type name of SERVICE."
 458   (nth 3 service))
 459
 460 (defun zeroconf-service-domain (service)
 461   "Return the domain name of SERVICE."
 462   (nth 4 service))
 463
 464 (defun zeroconf-service-flags (service)
 465   "Return the flags of SERVICE."
 466   (nth 5 service))
 467
 468 (defun zeroconf-service-host (service)
 469   "Return the host name of SERVICE."
 470   (nth 5 (zeroconf-resolve-service service)))
 471
 472 (defun zeroconf-service-aprotocol (service)
 473   "Return the aprotocol number of SERVICE."
 474   (nth 6 (zeroconf-resolve-service service)))
 475
 476 (defun zeroconf-service-address (service)
 477   "Return the IP address of SERVICE."
 478   (nth 7 (zeroconf-resolve-service service)))
 479
 480 (defun zeroconf-service-port (service)
 481   "Return the port number of SERVICE."
 482   (nth 8 (zeroconf-resolve-service service)))
 483
 484 (defun zeroconf-service-txt (service)
 485   "Return the text strings of SERVICE."
 486   (nth 9 (zeroconf-resolve-service service)))
 487
 488 \f
 489 ;;; Services signaling.
 490
 491 ;; Register for the service type browser.  Service registrations will
 492 ;; happen in `zeroconf-service-type-browser-handler', when there is an
 493 ;; "ItemNew" signal from the service type browser.
 494 (defun zeroconf-init (&optional domain)
 495   "Instantiate an Avahi service type browser for domain DOMAIN.
 496 DOMAIN is a string, like \"dns-sd.org\" or \"local\".  When
 497 DOMAIN is nil, the local domain is used."
 498   (when (and (or (null domain) (stringp domain))
 499              (dbus-ping :system zeroconf-service-avahi)
 500              (dbus-call-method
 501               :system zeroconf-service-avahi zeroconf-path-avahi
 502               zeroconf-interface-avahi-server "GetVersionString"))
 503
 504     ;; Reset all stored values.
 505     (setq zeroconf-path-avahi-service-type-browser nil
 506           zeroconf-avahi-current-domain (or domain
 507                                             zeroconf-avahi-domain-unspec))
 508     (clrhash zeroconf-path-avahi-service-browser-hash)
 509     (clrhash zeroconf-path-avahi-service-resolver-hash)
 510     (clrhash zeroconf-services-hash)
 511     (clrhash zeroconf-resolved-services-hash)
 512     (clrhash zeroconf-service-added-hooks-hash)
 513     (clrhash zeroconf-service-removed-hooks-hash)
 514
 515     ;; Register a service type browser.
 516     (let ((object-path (zeroconf-register-service-type-browser)))
 517       ;; Register the signals.
 518       (dolist (member '("ItemNew" "ItemRemove" "Failure"))
 519         (dbus-register-signal
 520          :system zeroconf-service-avahi object-path
 521          zeroconf-interface-avahi-service-type-browser member
 522          'zeroconf-service-type-browser-handler)))
 523
 524     ;; Register state changed signal.
 525     (dbus-register-signal
 526      :system zeroconf-service-avahi zeroconf-path-avahi
 527      zeroconf-interface-avahi-service-type-browser "StateChanged"
 528      'zeroconf-service-type-browser-handler)))
 529
 530 (defun zeroconf-register-service-type-browser ()
 531   "Register a service type browser at the Avahi daemon."
 532   (or zeroconf-path-avahi-service-type-browser
 533       (setq zeroconf-path-avahi-service-type-browser
 534             (dbus-call-method
 535              :system zeroconf-service-avahi zeroconf-path-avahi
 536              zeroconf-interface-avahi-server "ServiceTypeBrowserNew"
 537              zeroconf-avahi-interface-unspec
 538              zeroconf-avahi-protocol-unspec
 539              zeroconf-avahi-current-domain
 540              zeroconf-avahi-flags-unspec))))
 541
 542 (defun zeroconf-service-type-browser-handler (&rest val)
 543   "Registered service type browser handler at the Avahi daemon."
 544   (when zeroconf-debug
 545     (message "zeroconf-service-type-browser-handler: %s %S"
 546              (dbus-event-member-name last-input-event) val))
 547   (cond
 548    ((string-equal (dbus-event-member-name last-input-event) "ItemNew")
 549     ;; Parameters: (interface protocol type domain flags)
 550     ;; Register a service browser.
 551     (let ((object-path (zeroconf-register-service-browser (nth-value 2 val))))
 552       ;; Register the signals.
 553       (dolist (member '("ItemNew" "ItemRemove" "Failure"))
 554         (dbus-register-signal
 555          :system zeroconf-service-avahi object-path
 556          zeroconf-interface-avahi-service-browser member
 557          'zeroconf-service-browser-handler))))))
 558
 559 (defun zeroconf-register-service-browser (type)
 560   "Register a service browser at the Avahi daemon."
 561   (or (gethash type zeroconf-path-avahi-service-browser-hash nil)
 562       (puthash type
 563                (dbus-call-method
 564                 :system zeroconf-service-avahi zeroconf-path-avahi
 565                 zeroconf-interface-avahi-server "ServiceBrowserNew"
 566                 zeroconf-avahi-interface-unspec
 567                 zeroconf-avahi-protocol-unspec
 568                 type
 569                 zeroconf-avahi-current-domain
 570                 zeroconf-avahi-flags-unspec)
 571                zeroconf-path-avahi-service-browser-hash)))
 572
 573 (defun zeroconf-service-browser-handler (&rest val)
 574   "Registered service browser handler at the Avahi daemon."
 575   ;; Parameters: (interface protocol name type domain flags)
 576   (when zeroconf-debug
 577     (message "zeroconf-service-browser-handler: %s %S"
 578              (dbus-event-member-name last-input-event) val))
 579   (let* ((name (zeroconf-service-name val))
 580          (type (zeroconf-service-type val))
 581          (key (concat name "/" type))
 582          (ahook (gethash type zeroconf-service-added-hooks-hash nil))
 583          (rhook (gethash type zeroconf-service-removed-hooks-hash nil)))
 584     (cond
 585      ((string-equal (dbus-event-member-name last-input-event) "ItemNew")
 586       ;; Add new service.
 587       (puthash key val zeroconf-services-hash)
 588       (run-hook-with-args 'ahook val))
 589
 590      ((string-equal (dbus-event-member-name last-input-event) "ItemRemove")
 591       ;; Remove the service.
 592       (remhash key zeroconf-services-hash)
 593       (remhash key zeroconf-resolved-services-hash)
 594       (run-hook-with-args 'rhook val)))))
 595
 596 (defun zeroconf-register-service-resolver (name type)
 597   "Register a service resolver at the Avahi daemon."
 598   (let ((key (concat name "/" type)))
 599     (or (gethash key zeroconf-path-avahi-service-resolver-hash nil)
 600         (puthash key
 601                  (dbus-call-method
 602                   :system zeroconf-service-avahi zeroconf-path-avahi
 603                   zeroconf-interface-avahi-server "ServiceResolverNew"
 604                   zeroconf-avahi-interface-unspec
 605                   zeroconf-avahi-protocol-unspec
 606                   name type
 607                   zeroconf-avahi-current-domain
 608                   zeroconf-avahi-protocol-unspec
 609                   zeroconf-avahi-flags-unspec)
 610                  zeroconf-resolved-services-hash))))
 611
 612 (defun zeroconf-service-resolver-handler (&rest val)
 613   "Registered service resolver handler at the Avahi daemon."
 614   ;; Parameters: (interface protocol name type domain host aprotocol
 615   ;;              address port txt flags)
 616   ;; The "TXT" field has the signature "aay".  Transform to "as".
 617   (let ((elt (nth 9 val)))
 618     (while elt
 619       (setcar elt (dbus-byte-array-to-string (car elt)))
 620       (setq elt (cdr elt))))
 621   (when zeroconf-debug
 622     (message "zeroconf-service-resolver-handler: %s %S"
 623              (dbus-event-member-name last-input-event) val))
 624   (cond
 625    ;; A new service has been detected.  Add it to
 626    ;; `zeroconf-resolved-services-hash'.
 627    ((string-equal (dbus-event-member-name last-input-event) "Found")
 628     (puthash
 629      (concat (zeroconf-service-name val) "/" (zeroconf-service-type val))
 630      val zeroconf-resolved-services-hash))))
 631
 632 \f
 633 ;;; Services publishing.
 634
 635 (defun zeroconf-publish-service (name type domain host port address txt)
 636   "Publish a service at the Avahi daemon.
 637 For the description of arguments, see `zeroconf-resolved-services-hash'."
 638   ;; NAME and TYPE must not be empty.
 639   (when (zerop (length name))
 640     (error "Invalid argument NAME: %s" name))
 641   (when (zerop (length type))
 642     (error "Invalid argument TYPE: %s" type))
 643
 644   ;; Set default values for DOMAIN, HOST and PORT.
 645   (when (zerop (length domain))
 646     (setq domain (zeroconf-get-domain)))
 647   (when (zerop (length host))
 648     (setq host (zeroconf-get-host-domain)))
 649   (when (null port)
 650     (setq port 0))
 651
 652   ;; Create an entry in the daemon.
 653   (let ((object-path
 654          (dbus-call-method
 655           :system zeroconf-service-avahi zeroconf-path-avahi
 656           zeroconf-interface-avahi-server "EntryGroupNew"))
 657         result)
 658
 659     ;; The TXT field has the signature "as".  Transform to "aay".
 660     (dolist (elt txt)
 661       (add-to-list 'result (dbus-string-to-byte-array elt)))
 662
 663     ;; Add the service.
 664     (dbus-call-method
 665      :system zeroconf-service-avahi object-path
 666      zeroconf-interface-avahi-entry-group "AddService"
 667      zeroconf-avahi-interface-unspec
 668      zeroconf-avahi-protocol-unspec
 669      zeroconf-avahi-flags-unspec
 670      name type domain host :uint16 port (append '(:array) result))
 671
 672     ;; Add the address.
 673     (unless (zerop (length address))
 674       (dbus-call-method
 675        :system zeroconf-service-avahi object-path
 676        zeroconf-interface-avahi-entry-group "AddAddress"
 677        zeroconf-avahi-interface-unspec
 678        zeroconf-avahi-protocol-unspec
 679        zeroconf-avahi-flags-unspec
 680        host address))
 681
 682     ;; Make it persistent in the daemon.
 683     (dbus-call-method
 684      :system zeroconf-service-avahi object-path
 685      zeroconf-interface-avahi-entry-group "Commit")))
 686
 687 (provide 'zeroconf)
 688
 689 ;;; zeroconf.el ends here