AvahiCore - house keeping

Google disabled bind() to a netlink socket in api 30.  This change disables
the netlink socket used in avahi-core on Android which means there is no
async network interface info.  When the apps starts, a list of interfaces
is gotten with getifaddrs() and avahi uses this list to monitor.  Avahi
does not monitor while the app sleeps and deletes the monitor.

avahi-core/iface-android-api-30.c

@@ -0,0 +1,135 @@
+/***
+  This file is part of avahi.
+
+  avahi 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.
+
+  avahi 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.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <string.h>
+#include <net/if.h>
+#include <linux/if_addr.h>
+#include <netinet/in.h>
+#include <ifaddrs.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <avahi-common/malloc.h>
+#include "iface.h"
+#include "addr-util.h"
+
+int avahi_interface_monitor_init_osdep(AvahiInterfaceMonitor *m) {
+    AvahiHwInterface *hw;
+    AvahiInterface *i;
+    AvahiAddress raddr;
+    AvahiInterfaceAddress *addr;
+    struct ifaddrs *addrs_list;
+    struct ifaddrs *ifa;
+
+    getifaddrs(&addrs_list);
+    for (ifa = addrs_list; ifa; ifa = ifa->ifa_next) {
+        if (!ifa->ifa_addr || (ifa->ifa_addr->sa_family != AF_INET && ifa->ifa_addr->sa_family != AF_INET6))
+            continue;
+
+        unsigned int ifi_index = if_nametoindex(ifa->ifa_name);
+        if (!(hw = avahi_interface_monitor_get_hw_interface(m, ifi_index))) {
+
+            /* No object found, so let's create a new
+             * one. avahi_hw_interface_new() will call
+             * avahi_interface_new() internally twice for IPv4 and
+             * IPv6, so there is no need for us to do that
+             * ourselves */
+            if ((hw = avahi_hw_interface_new(m, (AvahiIfIndex) ifi_index))) {
+                hw->flags_ok =
+                        (ifa->ifa_flags & IFF_UP) &&
+                        (!m->server->config.use_iff_running || (ifa->ifa_flags & IFF_RUNNING)) &&
+                        !(ifa->ifa_flags & IFF_LOOPBACK) &&
+                        (ifa->ifa_flags & IFF_MULTICAST) &&
+                        (m->server->config.allow_point_to_point || !(ifa->ifa_flags & IFF_POINTOPOINT));
+
+                avahi_free(hw->name);
+                hw->name = avahi_strndup(ifa->ifa_name, strlen(ifa->ifa_name));
+
+// fixme - these mtu values are differnet from what ip addr reports
+//				struct ifreq ifr;
+//				memset(&ifr, 0, sizeof(ifr));
+//				int sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+//				strcpy(ifr.ifr_name, hw->name);
+//				if (ioctl(sock, SIOCGIFFLAGS, &ifr) < 0) {
+//					//perror("SIOCGIFFLAGS");
+//				}
+//				close(sock);
+//				hw->mtu = ifr.ifr_mtu;
+
+                /* Check whether this interface is now "relevant" for us. If
+                 * it is Avahi will start to announce its records on this
+                 * interface and send out queries for subscribed records on
+                 * it */
+                avahi_hw_interface_check_relevant(hw);
+
+                /* Update any associated RRs of this interface. (i.e. the
+                 * _workstation._tcp record containing the MAC address) */
+                avahi_hw_interface_update_rrs(hw, 0);
+            } else {
+                goto out;
+            }
+        }
+
+        /* Try to get a reference to our AvahiInterface object for the
+         * interface this address is assigned to. If ther is no object
+         * for this interface, we ignore this address. */
+        if (!(i = avahi_interface_monitor_get_interface(m, (AvahiIfIndex) ifi_index, avahi_af_to_proto(ifa->ifa_addr->sa_family))))
+            continue;
+
+        avahi_address_from_sockaddr(ifa->ifa_addr, &raddr);
+
+        /* This address is new or has been modified, so let's get an object for it */
+        if (!(addr = avahi_interface_monitor_get_address(m, i, &raddr)))
+
+            /* Mmm, no object existing yet, so let's create a new one */
+            if (!(addr = avahi_interface_address_new(m, i, &raddr, 4)))
+                continue; /* OOM */
+
+        /* Update the scope field for the address */
+        //addr->global_scope = 0;//ifaddrmsg->ifa_scope == RT_SCOPE_UNIVERSE || ifaddrmsg->ifa_scope == RT_SCOPE_SITE;
+        addr->deprecated = !!(ifa->ifa_flags & IFA_F_DEPRECATED);
+
+        /* Avahi only considers interfaces with at least one address
+         * attached relevant. Since we migh have added or removed an
+         * address, let's have it check again whether the interface is
+         * now relevant */
+        avahi_interface_check_relevant(i);
+
+        /* Update any associated RRs, like A or AAAA for our new/removed address */
+        avahi_interface_update_rrs(i, 0);
+    }
+
+    m->list_complete = 1;
+    avahi_interface_monitor_check_relevant(m);
+
+    /* And update all RRs attached to any interface */
+    avahi_interface_monitor_update_rrs(m, 0);
+
+out:
+    freeifaddrs(addrs_list);
+
+    return 0;
+}
+
+void avahi_interface_monitor_free_osdep(AvahiInterfaceMonitor *m) {
+    (void) m;
+}
+
+void avahi_interface_monitor_sync(AvahiInterfaceMonitor *m) {
+    (void) m;
+}

avahicore.cpp

@@ -36,32 +36,25 @@
 class QZeroConfPrivate
 {
 public:
-	QZeroConfPrivate(QZeroConf *parent)
+	QZeroConfPrivate(QZeroConf *parent) { pub = parent; }
+
+	void createOrDeleteServer()
 	{
 		qint32 error;
 
-		pub = parent;
-		group = NULL;
-		browser = NULL;
-		txt = NULL;
-		ready = 0;
-		registerWaiting = 0;
-
-		poll = avahi_qt_poll_get();
-		if (!poll) {
-			return;
-		}
-
-		avahi_server_config_init(&config);
-		config.publish_workstation = 0;
-
-		if (!referenceCount) {
+		if (!serviceObjectCount && !browserObjectCount) {
+			avahi_server_free(server);
+			avahi_server_config_free(&config);
+			server = nullptr;
+		} else if (!server) {
+			poll = avahi_qt_poll_get();
+			if (!poll) {
+				return;
+			}
+			avahi_server_config_init(&config);
+			config.publish_workstation = 0;
 			server = avahi_server_new(poll, &config, serverCallback, this, &error);
 		}
-		referenceCount++;
-		if (!server) {
-			return;
-		}
 	}
 
 	static void serverCallback(AvahiServer *, AvahiServerState state, AVAHI_GCC_UNUSED void * userdata)
@@ -69,10 +62,10 @@ public:
 		QZeroConfPrivate *ref = static_cast<QZeroConfPrivate *>(userdata);
 		switch (state) {
 			case AVAHI_SERVER_RUNNING:
-				ref->ready = 1;
-                if (ref->registerWaiting) {
-                    ref->registerWaiting = 0;
-                    ref->registerService(ref->name.toUtf8(), ref->type.toUtf8(), ref->domain.toUtf8(), ref->port);
+				ref->ready = true;
+				if (ref->registerWaiting) {
+					ref->registerWaiting = false;
+					ref->registerService(ref->name.toUtf8(), ref->type.toUtf8(), ref->domain.toUtf8(), ref->port);
 				}
 				break;
 			case AVAHI_SERVER_COLLISION:
@@ -228,6 +221,9 @@ public:
 		for (r = resolvers.begin(); r != resolvers.end(); r++)
 			avahi_s_service_resolver_free(*r);
 		resolvers.clear();
+
+		browserObjectCount--;
+		createOrDeleteServer();
 	}
 
 	void registerService(const char *name, const char *type, const char *domain, quint16 port)
@@ -258,20 +254,24 @@ public:
 	QZeroConf *pub;
 	const AvahiPoll *poll;
 	static AvahiServer *server;
-	static quint32 referenceCount;
-	AvahiServerConfig config;
-	AvahiSEntryGroup *group;
-	AvahiSServiceBrowser *browser;
+	static size_t serviceObjectCount;
+	static size_t browserObjectCount;
+	static AvahiServerConfig config;
+	AvahiSEntryGroup *group = nullptr;
+	AvahiSServiceBrowser *browser = nullptr;
 	AvahiProtocol aProtocol;
 	QMap <QString, AvahiSServiceResolver *> resolvers;
-	AvahiStringList *txt;
-	bool ready, registerWaiting;
+	AvahiStringList *txt = nullptr;
+	bool ready = false;
+	bool registerWaiting = false;
 	QString name, type, domain;
 	qint32 port;
 };
 
 AvahiServer* QZeroConfPrivate::server = nullptr;
-quint32 QZeroConfPrivate::referenceCount = 0;
+AvahiServerConfig QZeroConfPrivate::config;
+size_t QZeroConfPrivate::serviceObjectCount = 0;
+size_t QZeroConfPrivate::browserObjectCount = 0;
 
 QZeroConf::QZeroConf(QObject *parent) : QObject (parent)
 {
@@ -284,9 +284,7 @@ QZeroConf::~QZeroConf()
 	avahi_string_list_free(pri->txt);
 	pri->broswerCleanUp();
 	avahi_server_config_free(&pri->config);
-	pri->referenceCount--;
-	if (!pri->referenceCount)
-		avahi_server_free(pri->server);
+	stopServicePublish();
 	delete pri;
 }
 
@@ -296,10 +294,14 @@ void QZeroConf::startServicePublish(const char *name, const char *type, const ch
 		emit error(QZeroConf::serviceRegistrationFailed);
 		return;
 	}
+
+	pri->serviceObjectCount++;
+	pri->createOrDeleteServer();
+
 	if (pri->ready)
 		pri->registerService(name, type, domain, port);
 	else {
-		pri->registerWaiting = 1;
+		pri->registerWaiting = true;
 		pri->name = name;
 		pri->type = type;
 		pri->domain = domain;
@@ -312,6 +314,8 @@ void QZeroConf::stopServicePublish(void)
 	if (pri->group) {
 		avahi_s_entry_group_free(pri->group);
 		pri->group = NULL;
+		pri->serviceObjectCount--;
+		pri->createOrDeleteServer();
 	}
 }
 
@@ -348,6 +352,9 @@ void QZeroConf::startBrowser(QString type, QAbstractSocket::NetworkLayerProtocol
 	if (pri->browser)
 		emit error(QZeroConf::browserFailed);
 
+	pri->browserObjectCount++;
+	pri->createOrDeleteServer();
+
 	switch (protocol) {
 		case QAbstractSocket::IPv4Protocol: pri->aProtocol = AVAHI_PROTO_INET; break;
 		case QAbstractSocket::IPv6Protocol: pri->aProtocol = AVAHI_PROTO_INET6; break;

qtzeroconf.pri

@@ -69,7 +69,7 @@ ubports|android: {
 		DEFINES+= HAVE_STRLCPY GETTEXT_PACKAGE
 	}
 	ubports: {
-		DEFINES+= _GNU_SOURCE GETTEXT_PACKAGE
+		DEFINES+= _GNU_SOURCE GETTEXT_PACKAGE HAVE_NETLINK
 	}
 	SOURCES+= $$ACM/address.c
 	SOURCES+= $$ACM/alternative.c
@@ -84,7 +84,6 @@ ubports|android: {
 	SOURCES+= $$ACM/timeval.c
 	SOURCES+= $$ACM/utf8.c
 	# avahi-core
-	DEFINES+= HAVE_NETLINK
 	SOURCES+= $$ACR/addr-util.c
 	SOURCES+= $$ACR/announce.c
 	SOURCES+= $$ACR/browse.c
@@ -99,10 +98,15 @@ ubports|android: {
 	SOURCES+= $$ACR/fdutil.c
 	SOURCES+= $$ACR/hashmap.c
 	SOURCES+= $$ACR/iface.c
-	SOURCES+= $$ACR/iface-linux.c
+	android: {
+		SOURCES+= $$ACR/iface-android-api-30.c
+	}
+	ubports: {
+		SOURCES+= $$ACR/iface-linux.c
+		SOURCES+= $$ACR/netlink.c
+	}
 	SOURCES+= $$ACR/log.c
 	SOURCES+= $$ACR/multicast-lookup.c
-	SOURCES+= $$ACR/netlink.c
 	SOURCES+= $$ACR/prioq.c
 	SOURCES+= $$ACR/probe-sched.c
 	SOURCES+= $$ACR/querier.c