source: source/ariba/communication/networkinfo/NetworkChangeDetection.cpp@ 12765

// [License]
// The Ariba-Underlay Copyright
//
// Copyright (c) 2008-2009, Institute of Telematics, UniversitÀt Karlsruhe (TH)
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// UniversitÀt Karlsruhe (TH)
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// Germany
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// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
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// [License]

#include "NetworkChangeDetection.h"

#include <string>
#include <algorithm>
#include <cerrno>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <boost/bind.hpp>
#include <sys/socket.h>

extern "C" {
        #include <linux/netlink.h>
        #include <linux/rtnetlink.h>
}

#include "ariba/utility/system/SystemQueue.h"

using std::find;
using ariba::utility::SystemQueue;
using ariba::utility::SystemEventType;

namespace ariba {
namespace communication {

use_logging_cpp(NetworkChangeDetection);
SystemEventType NetworkChangeDetectionEventType("NetworkChangeDetectionEventType");

NetworkChangeDetection::NetworkChangeDetection()
        : running( false ), monitoringThread( NULL ), routingSocket( -1 ){
        startMonitoring();
}

NetworkChangeDetection::~NetworkChangeDetection(){
        stopMonitoring();
}

void NetworkChangeDetection::registerNotification(NetworkChangeInterface* callback){

        RegistrationList::iterator i = find(
                registrations.begin(), registrations.end(), callback );

        if( i == registrations.end() )
                registrations.push_back( callback );
}

void NetworkChangeDetection::unregisterNotification(NetworkChangeInterface* callback){

        RegistrationList::iterator i = find(
                registrations.begin(), registrations.end(), callback );

        if( i != registrations.end() )
                registrations.erase( i );
}

void NetworkChangeDetection::startMonitoring(){

        logging_debug( "starting network change monitoring ..." );

        running = true;
        monitoringThread = new boost::thread(
                boost::bind(&NetworkChangeDetection::monitoringThreadFunc, this) );
}

void NetworkChangeDetection::stopMonitoring(){

        logging_debug( "stopping network change monitoring ..." );

        // trigger the blocking read to end
        running = false;

        shutdown( routingSocket, SHUT_RDWR );
        close( routingSocket );

        // end the monitoring thread
        monitoringThread->join();

        delete monitoringThread;
        monitoringThread = NULL;
}

void NetworkChangeDetection::monitoringThreadFunc(NetworkChangeDetection* obj){

        //
        // Most information about this routing socket interface is available
        // when searching for NETLINK_ROUTE and in http://www.faqs.org/rfcs/rfc3549.html
        // A small program that uses this stuff is ifplugd, nice reference for
        // getting network interface notifications using routing sockets
        // (e.g. http://ifplugd.sourcearchive.com/documentation/0.26/ifmonitor_8c-source.html)
        // And the best resource is the linux code ... http://www.srcdoc.com/linux_2.2.26/rtnetlink_8h-source.html
        // More:
        //      http://m.linuxjournal.com/article/8498
        //      http://lkml.indiana.edu/hypermail/linux/net/0508.2/0016.html
        //      http://infrahip.hiit.fi/hipl/release/1.0.1/hipl.1.0.1/hipd/netdev.c
        //      http://www.google.de/codesearch?hl=de&q=rtmsg_ifinfo+show:Ndy7Mq7IdCw:aylASy5mtF0:ClfaxlLp-PU&source=universal&cs_p=ftp://ftp.kernel.org/pub/linux/kernel/v2.4/linux-2.4.18.tar.gz&cs_f=linux/net/core/rtnetlink.c#l490
        //      http://www.google.com/codesearch?hl=en&q=RTM_NEWADDR+NETLINK_ROUTE+show:eUekvGbF94M:iCwmLwtnVbU:38qoeYp--0A&sa=N&cd=1&ct=rc&cs_p=ftp://ftp.stacken.kth.se/pub/arla/arla-0.42.tar.gz&cs_f=arla-0.42/lib/roken/getifaddrs.c
        //      http://www.google.com/codesearch?hl=en&q=RTMGRP_LINK+rtm_newaddr+nl_groups+show:sUV8mV--Lb4:gk0jx_xv0Yg:ZB9MN7Fgkgg&sa=N&cd=1&ct=rc&cs_p=http://freshmeat.net/redir/strongswan/60428/url_bz2/strongswan-4.1.2.tar.bz2&cs_f=strongswan-4.1.4/src/charon/kernel/kernel_interface.c#l689
        //

        //
        // open the netlink routing socket, don't need raw sockets here!
        //

        obj->routingSocket = socket( PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE );
        if( obj->routingSocket < 0 ){
                logging_error("could not connect to routing socket: " +
                                        std::string(strerror(errno)));
                return;
        }

        //
        // set a socket read timeout. this is actually bad, but closing
        // the blocking socket using shutdown, close, or writing EOF to
        // the socket did not work. this seems to be a bug related to
        // routing sockets that will not close when in blocking mode
        //

        struct timeval tv;
        tv.tv_sec = 1;
        tv.tv_usec = 0;

        setsockopt( obj->routingSocket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv) );

        //
        // bind the netlink routing socket to our local address
        // for the nl_groups, see http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/include/linux/rtnetlink.h#L520
        // we listen on ipv4/6 new/delete address and link up/down notifications
        //

        struct sockaddr_nl addr;
        memset( &addr, 0, sizeof(addr) );
        addr.nl_family = AF_NETLINK;
        addr.nl_groups = RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR | RTMGRP_LINK;
        addr.nl_pid    = getpid();

        int ret = bind( obj->routingSocket, (struct sockaddr*)&addr, sizeof(addr) );
        if( ret < 0 ){
                close( obj->routingSocket );
                logging_error( "could not bind routing socket: " + std::string(strerror(errno)) );
                return;
        }

        //
        // read from the netlink routing socket
        //

        logging_debug( "network change monitoring started" );

        while( obj->running ){

                char buffer[1024];
                struct nlmsghdr* header = (struct nlmsghdr*)buffer;

                int bytesRead = recv( obj->routingSocket, &buffer, sizeof(buffer), 0 );

                if( bytesRead < 0 ){

                        // socket timeout, just continue
                        if( errno == EWOULDBLOCK ) continue;

                        // triggered by shutdown() function in stopMonitoring
                        if( errno == EBADF ) return;

                        // gracefull exit by signals
                        if( errno == EAGAIN || errno == EINTR ) return;

                        // all others are some kind of error
                        logging_error( "could not read from routing socket: " +
                                                        std::string(strerror(errno)) );
                        break;
                }

                for( ; bytesRead > 0; header = NLMSG_NEXT(header, bytesRead)) {
                        if (!NLMSG_OK(header, (size_t)bytesRead) ||
                                (size_t) bytesRead < sizeof(struct nlmsghdr) ||
                                (size_t) bytesRead < (size_t)header->nlmsg_len) {
                                continue;
                        }

                        // somehow all notifications with pid=0 are
                        // invalid and occur much too often
                        if(header->nlmsg_pid == 0) continue;

                        //
                        // here we evaluate the routing netlink message. for, the following
                        // messages are of interest:
                        //      RTM_NEWADDR, RTM_DELADDR -> new address on iface, address deleted from iface
                        //

                        NetworkChangeInterface::NetworkChangeInfo changeInfo;

                        switch( header->nlmsg_type ){

                                //
                                // handle network address configuration changes
                                // --> network layer notifications
                                //

                                case RTM_NEWADDR:
                                case RTM_DELADDR:

                                        changeInfo = obj->extractAddressEvent( header );
                                        break;

                                //
                                // other RTM message are ignored in case
                                // we did subscribe using nl_groups (see above)
                                //

                                default: break;

                        } // switch( header->nlmsg_type )

                        logging_info( "network change detected: [" << changeInfo << "]" );

                        // put noficiation event into the system queue for main
                        // thread synchronization. will be handled in NetworkChangeDetection::handleSystemEvent()
                        // that will run synchronized with the main thread

                        SystemQueue::instance().scheduleEvent(
                                SystemEvent( obj, NetworkChangeDetectionEventType,
                                        new NetworkChangeInterface::NetworkChangeInfo(changeInfo)));

                } // for( ; bytesRead > 0; header = NLMSG_NEXT(header, bytesRead))
        } // while( running )

        logging_debug( "network change monitoring stopped" );
}

NetworkChangeInterface::NetworkChangeInfo NetworkChangeDetection::extractAddressEvent(struct nlmsghdr* header){
        NetworkChangeInterface::NetworkChangeInfo changeInfo;

        //
        // handle network address configuration changes
        // addresses are added/removed from an interface
        //

        if( header->nlmsg_type == RTM_NEWADDR ){
                logging_debug("network change message RTM_NEWADDR");
                changeInfo.type = NetworkChangeInterface::EventTypeInterfaceUp;
        }else if( header->nlmsg_type == RTM_DELADDR ){
                logging_debug("network change message RTM_DELADDR");
                changeInfo.type = NetworkChangeInterface::EventTypeInterfaceDown;
        }

        struct ifaddrmsg* detailAddr = (struct ifaddrmsg*)NLMSG_DATA(header);
        changeInfo.interface = networkInformation.getInterface( detailAddr->ifa_index );

        return changeInfo;
}

void NetworkChangeDetection::handleSystemEvent(const SystemEvent& event){

        NetworkChangeInterface::NetworkChangeInfo* changeInfo = event.getData<NetworkChangeInterface::NetworkChangeInfo>();
        const NetworkChangeDetection* obj = (const NetworkChangeDetection*)event.getListener();

        RegistrationList::const_iterator i = obj->registrations.begin();
        RegistrationList::const_iterator iend = obj->registrations.end();

        for( ; i != iend; i++ )
                (*i)->onNetworkChange(*changeInfo);

        delete changeInfo;
}

}} // namespace ariba, communication