DNS SD implementation for macOS (Bonjour)

CMakeLists.txt

@@ -148,12 +148,12 @@ endif()
 
 if(WITH_LOCAL_BACKEND)
 	add_definitions(-DLOCAL_BACKEND=1)
-	set(LIBIIO_CFILES ${LIBIIO_CFILES} local.c)
+	list(APPEND LIBIIO_CFILES local.c)
 
 	# Link with librt if present
 	find_library(LIBRT_LIBRARIES rt)
 	if (LIBRT_LIBRARIES)
-		set(LIBS_TO_LINK ${LIBS_TO_LINK} ${LIBRT_LIBRARIES})
+		list(APPEND LIBS_TO_LINK ${LIBRT_LIBRARIES})
 	endif()
 
 	option(WITH_LOCAL_CONFIG "Read local context attributes from /etc/libiio.ini" OFF)
@@ -164,7 +164,7 @@ if(WITH_LOCAL_BACKEND)
 			message(SEND_ERROR "WITH_LOCAL_CONFIG option requires libini to be installed")
 		else()
 			include_directories(${LIBINI_INCLUDE_DIR})
-			set(LIBS_TO_LINK ${LIBS_TO_LINK} ${LIBINI_LIBRARIES})
+			list(APPEND LIBS_TO_LINK ${LIBINI_LIBRARIES})
 		endif()
 	endif()
 endif()
@@ -178,8 +178,8 @@ if (LIBUSB_LIBRARIES AND LIBUSB_INCLUDE_DIR)
 
 	if(WITH_USB_BACKEND)
 		add_definitions(-DUSB_BACKEND=1)
-		set(LIBIIO_CFILES ${LIBIIO_CFILES} usb.c)
-		set(LIBS_TO_LINK ${LIBS_TO_LINK} ${LIBUSB_LIBRARIES})
+		list(APPEND LIBIIO_CFILES usb.c)
+		list(APPEND LIBS_TO_LINK ${LIBUSB_LIBRARIES})
 		set(IIOD_CLIENT 1)
 		set(NEED_LIBXML2 1)
 		set(NEED_THREADS 1)
@@ -188,10 +188,8 @@ if (LIBUSB_LIBRARIES AND LIBUSB_INCLUDE_DIR)
 
 		set(TEMP ${CMAKE_REQUIRED_LIBRARIES})
 		set(TEMP1 ${CMAKE_REQUIRED_INCLUDES})
-		set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES}
-			${LIBUSB_LIBRARIES})
-		set(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES}
-			${LIBUSB_INCLUDE_DIR})
+		list(APPEND CMAKE_REQUIRED_LIBRARIES ${LIBUSB_LIBRARIES})
+		list(APPEND CMAKE_REQUIRED_INCLUDES ${LIBUSB_INCLUDE_DIR})
 		check_symbol_exists(libusb_get_version libusb.h
 			HAS_LIBUSB_GETVERSION)
 		set(CMAKE_REQUIRED_LIBRARIES ${TEMP})
@@ -214,8 +212,8 @@ if (LIBSERIALPORT_LIBRARIES AND LIBSERIALPORT_INCLUDE_DIR)
 			SET(WITH_SERIAL_BACKEND OFF)
 		else()
 			add_definitions(-DSERIAL_BACKEND=1)
-			set(LIBIIO_CFILES ${LIBIIO_CFILES} serial.c)
-			set(LIBS_TO_LINK ${LIBS_TO_LINK} ${LIBSERIALPORT_LIBRARIES})
+			list(APPEND LIBIIO_CFILES serial.c)
+			list(APPEND LIBS_TO_LINK ${LIBSERIALPORT_LIBRARIES})
 
 			set(NEED_THREADS 1)
 			set(IIOD_CLIENT 1)
@@ -231,7 +229,7 @@ include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
 if(WITH_NETWORK_BACKEND)
 	message(STATUS "Building with Network back end support")
 	if (WIN32)
-		set(LIBS_TO_LINK ${LIBS_TO_LINK} wsock32 ws2_32)
+		list(APPEND LIBS_TO_LINK wsock32 ws2_32)
 	endif()
 
 	if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
@@ -251,18 +249,33 @@ if(WITH_NETWORK_BACKEND)
 	endif()
 
 	add_definitions(-DNETWORK_BACKEND=1)
-	set(LIBIIO_CFILES ${LIBIIO_CFILES} network.c)
+	list(APPEND LIBIIO_CFILES network.c)
 
 	find_library(AVAHI_CLIENT_LIBRARIES avahi-client)
 	find_library(AVAHI_COMMON_LIBRARIES avahi-common)
-	if(AVAHI_CLIENT_LIBRARIES AND AVAHI_COMMON_LIBRARIES)
-		message(STATUS "Building with Avahi, a zero-configuration networking (zeroconf) implementation")
-		set(HAVE_AVAHI ON)
+	if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+		find_library(CORE_SERVICES CoreServices)
+
+		message(STATUS "Building with CFNetServices, an Apple DNS SD implementation")
+		set(HAVE_DNS_SD ON)
+
+		list(APPEND LIBIIO_CFILES dns_sd_bonjour.c)
+		list(APPEND LIBS_TO_LINK ${CORE_SERVICES} )
+
+	elseif(AVAHI_CLIENT_LIBRARIES AND AVAHI_COMMON_LIBRARIES)
+		message(STATUS "Building with Avahi, a DNS SD implementation")
+		set(HAVE_DNS_SD ON)
+
+		list(APPEND LIBIIO_CFILES dns_sd_avahi.c)
 		set(AVAHI_LIBRARIES ${AVAHI_CLIENT_LIBRARIES} ${AVAHI_COMMON_LIBRARIES})
-		set(LIBS_TO_LINK ${LIBS_TO_LINK} ${AVAHI_LIBRARIES})
+		list(APPEND LIBS_TO_LINK ${AVAHI_LIBRARIES})
 		set(AVAHI_SERVICE_INSTALL_DIR /etc/avahi/services/ CACHE PATH "default install path for Avahi service files")
 	else()
-		message(STATUS "Building without Avahi (zeroconf) support")
+		message(STATUS "Building without DNS-SD (Zeroconf) support")
+	endif()
+
+	if (HAVE_DNS_SD)
+		add_definitions(-DHAVE_DNS_SD=1)
 	endif()
 
 	set(NEED_THREADS 1)
@@ -289,10 +302,11 @@ if (LIBXML2_FOUND)
 	option(WITH_XML_BACKEND "Enable the XML backend" ON)
 
 	if (WITH_XML_BACKEND)
-		set(LIBIIO_CFILES ${LIBIIO_CFILES} xml.c)
+		list(APPEND LIBIIO_CFILES xml.c)
+
 		add_definitions(${LIBXML2_DEFINITIONS} -DXML_BACKEND=1)
 		include_directories(${LIBXML2_INCLUDE_DIR})
-		set(LIBS_TO_LINK ${LIBS_TO_LINK} ${LIBXML2_LIBRARIES})
+		list(APPEND LIBS_TO_LINK ${LIBXML2_LIBRARIES})
 	endif()
 endif()
 
@@ -305,19 +319,19 @@ if (NEED_THREADS)
 		find_library(PTHREAD_LIBRARIES pthread)
 
 		if (PTHREAD_LIBRARIES)
-			set(LIBS_TO_LINK ${LIBS_TO_LINK} ${PTHREAD_LIBRARIES})
+			list(APPEND LIBS_TO_LINK ${PTHREAD_LIBRARIES})
 		else()
 			message(WARNING "pthread library not found; support for threads will be disabled")
 			set(NO_THREADS ON)
 		endif()
 	else()
 	endif()
 
-	set(LIBIIO_CFILES ${LIBIIO_CFILES} lock.c)
+	list(APPEND LIBIIO_CFILES lock.c)
 endif()
 
 if (IIOD_CLIENT)
-	set(LIBIIO_CFILES ${LIBIIO_CFILES} iiod-client.c)
+	list(APPEND LIBIIO_CFILES iiod-client.c)
 	if (HAVE_AVAHI)
 		install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/iio.service DESTINATION ${AVAHI_SERVICE_INSTALL_DIR})
 	endif()
@@ -341,7 +355,7 @@ option(MATLAB_BINDINGS "Build MATLAB bindings" OFF)
 add_subdirectory(bindings)
 
 if (WITH_MATLAB_BINDINGS_API)
-	set(LIBIIO_EXTRA_HEADERS ${LIBIIO_EXTRA_HEADERS} bindings/matlab/iio-wrapper.h)
+	list(APPEND LIBIIO_EXTRA_HEADERS bindings/matlab/iio-wrapper.h)
 	add_definitions(-DMATLAB_BINDINGS_API=1)
 endif()
 

dns_sd_avahi.c

@@ -0,0 +1,142 @@
+/*
+ * libiio - Library for interfacing industrial I/O (IIO) devices
+ *
+ * Copyright (C) 2014-2020 Analog Devices, Inc.
+ * Author: Paul Cercueil <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * */
+
+#include "iio.h"
+
+#include <errno.h>
+#include <stdbool.h>
+#include <string.h>
+#include <time.h>
+
+#include <avahi-common/error.h>
+#include <avahi-common/simple-watch.h>
+#include <avahi-client/client.h>
+#include <avahi-client/lookup.h>
+
+#include "debug.h"
+
+struct avahi_discovery_data {
+	AvahiSimplePoll *poll;
+	AvahiAddress *address;
+	uint16_t *port;
+	bool found, resolved;
+};
+
+static void __avahi_resolver_cb(AvahiServiceResolver *resolver,
+		__notused AvahiIfIndex iface, __notused AvahiProtocol proto,
+		__notused AvahiResolverEvent event, __notused const char *name,
+		__notused const char *type, __notused const char *domain,
+		__notused const char *host_name, const AvahiAddress *address,
+		uint16_t port, __notused AvahiStringList *txt,
+		__notused AvahiLookupResultFlags flags, void *d)
+{
+	struct avahi_discovery_data *ddata = (struct avahi_discovery_data *) d;
+
+	memcpy(ddata->address, address, sizeof(*address));
+	*ddata->port = port;
+	ddata->resolved = true;
+	avahi_service_resolver_free(resolver);
+}
+
+static void __avahi_browser_cb(AvahiServiceBrowser *browser,
+		AvahiIfIndex iface, AvahiProtocol proto,
+		AvahiBrowserEvent event, const char *name,
+		const char *type, const char *domain,
+		__notused AvahiLookupResultFlags flags, void *d)
+{
+	struct avahi_discovery_data *ddata = (struct avahi_discovery_data *) d;
+	struct AvahiClient *client = avahi_service_browser_get_client(browser);
+
+	switch (event) {
+	default:
+	case AVAHI_BROWSER_NEW:
+		ddata->found = !!avahi_service_resolver_new(client, iface,
+				proto, name, type, domain,
+				AVAHI_PROTO_UNSPEC, 0,
+				__avahi_resolver_cb, d);
+		break;
+	case AVAHI_BROWSER_ALL_FOR_NOW:
+		if (ddata->found) {
+			while (!ddata->resolved) {
+				struct timespec ts;
+				ts.tv_sec = 0;
+				ts.tv_nsec = 4000000;
+				nanosleep(&ts, NULL);
+			}
+		}
+		/* fall-through */
+	case AVAHI_BROWSER_FAILURE:
+		avahi_simple_poll_quit(ddata->poll);
+		/* fall-through */
+	case AVAHI_BROWSER_CACHE_EXHAUSTED:
+		break;
+	}
+}
+
+int discover_host(char *addr_str, size_t addr_len, uint16_t *port)
+{
+	struct avahi_discovery_data ddata;
+	int ret = 0;
+	AvahiAddress address;
+	AvahiClient *client;
+	AvahiServiceBrowser *browser;
+	AvahiSimplePoll *poll = avahi_simple_poll_new();
+
+	memset(&address, 0, sizeof(address));
+	if (!poll)
+		return -ENOMEM;
+
+	client = avahi_client_new(avahi_simple_poll_get(poll),
+			0, NULL, NULL, &ret);
+	if (!client) {
+		ERROR("Unable to create Avahi DNS-SD client :%s\n",
+				avahi_strerror(ret));
+		goto err_free_poll;
+	}
+
+	memset(&ddata, 0, sizeof(ddata));
+	ddata.poll = poll;
+	ddata.address = &address;
+	ddata.port = port;
+
+	browser = avahi_service_browser_new(client,
+			AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC,
+			"_iio._tcp", NULL, 0, __avahi_browser_cb, &ddata);
+	if (!browser) {
+		ret = avahi_client_errno(client);
+		ERROR("Unable to create Avahi DNS-SD browser: %s\n",
+				avahi_strerror(ret));
+		goto err_free_client;
+	}
+
+	DEBUG("Trying to discover host\n");
+	avahi_simple_poll_loop(poll);
+
+	if (!ddata.found)
+		ret = ENXIO;
+
+	if (ret == 0)
+		avahi_address_snprint(addr_str, addr_len, &address);
+
+	avahi_service_browser_free(browser);
+err_free_client:
+	avahi_client_free(client);
+err_free_poll:
+	avahi_simple_poll_free(poll);
+	return -ret; /* we want a negative error code */
+}