Initial commit after restructure

network/environment/environment.go

@@ -0,0 +1,167 @@
+// Copyright Safing ICS Technologies GmbH. Use of this source code is governed by the AGPL license that can be found in the LICENSE file.
+
+package environment
+
+import (
+	"bytes"
+	"crypto/sha1"
+	"io"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/Safing/safing-core/log"
+)
+
+// TODO: find a good way to identify a network
+// best options until now:
+// MAC of gateway
+// domain parameter of dhcp
+
+// TODO: get dhcp servers on windows:
+// windows: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365917
+// this info might already be included in the interfaces api provided by golang!
+
+const (
+	UNKNOWN uint8 = iota
+	OFFLINE
+	LIMITED // local network only
+	PORTAL  // there seems to be an internet connection, but we are being intercepted
+	ONLINE
+)
+
+const (
+	connectivityRecheck = 2 * time.Second
+	interfacesRecheck   = 2 * time.Second
+	gatewaysRecheck     = 2 * time.Second
+	nameserversRecheck  = 2 * time.Second
+)
+
+var (
+	connectivity        uint8
+	connectivityLock    sync.Mutex
+	connectivityExpires = time.Now()
+
+	// interfaces        = make(map[*net.IP]net.Flags)
+	// interfacesLock    sync.Mutex
+	// interfacesExpires = time.Now()
+
+	gateways        = make([]*net.IP, 0)
+	gatewaysLock    sync.Mutex
+	gatewaysExpires = time.Now()
+
+	nameservers        = make([]Nameserver, 0)
+	nameserversLock    sync.Mutex
+	nameserversExpires = time.Now()
+
+	lastNetworkChange   *int64
+	lastNetworkChecksum []byte
+)
+
+type Nameserver struct {
+	IP     net.IP
+	Search []string
+}
+
+func init() {
+	lnc := int64(0)
+	lastNetworkChange = &lnc
+	go func() {
+		time.Sleep(1 * time.Second)
+		Connectivity()
+	}()
+
+	go monitorNetworkChanges()
+}
+
+// Connectivity returns the current state of connectivity to the network/Internet
+func Connectivity() uint8 {
+	// locking
+	connectivityLock.Lock()
+	defer connectivityLock.Unlock()
+	// cache
+	if connectivityExpires.After(time.Now()) {
+		return connectivity
+	}
+	// logic
+	// TODO: implement more methods
+	status, err := getConnectivityStateFromDbus()
+	if err != nil {
+		log.Warningf("environment: could not get connectivity: %s", err)
+		setConnectivity(UNKNOWN)
+		return UNKNOWN
+	}
+	setConnectivity(status)
+	return status
+}
+
+func setConnectivity(status uint8) {
+	if connectivity != status {
+		connectivity = status
+		connectivityExpires = time.Now().Add(connectivityRecheck)
+
+		var connectivityName string
+		switch connectivity {
+		case UNKNOWN:
+			connectivityName = "unknown"
+		case OFFLINE:
+			connectivityName = "offline"
+		case LIMITED:
+			connectivityName = "limited"
+		case PORTAL:
+			connectivityName = "portal"
+		case ONLINE:
+			connectivityName = "online"
+		default:
+			connectivityName = "invalid"
+		}
+		log.Infof("environment: connectivity changed to %s", connectivityName)
+	}
+}
+
+// ConnectionSucceeded should be called when a module was able to successfully connect to the internet (do not call too often)
+func ConnectionSucceeded() {
+	connectivityLock.Lock()
+	defer connectivityLock.Unlock()
+	setConnectivity(ONLINE)
+}
+
+func monitorNetworkChanges() {
+	// TODO: make more elegant solution
+	for {
+		time.Sleep(2 * time.Second)
+		hasher := sha1.New()
+		interfaces, err := net.Interfaces()
+		if err != nil {
+			log.Warningf("environment: failed to get interfaces: %s", err)
+			continue
+		}
+		for _, iface := range interfaces {
+			io.WriteString(hasher, iface.Name)
+			// log.Tracef("adding: %s", iface.Name)
+			io.WriteString(hasher, iface.Flags.String())
+			// log.Tracef("adding: %s", iface.Flags.String())
+			addrs, err := iface.Addrs()
+			if err != nil {
+				log.Warningf("environment: failed to get addrs from interface %s: %s", iface.Name, err)
+				continue
+			}
+			for _, addr := range addrs {
+				io.WriteString(hasher, addr.String())
+				// log.Tracef("adding: %s", addr.String())
+			}
+		}
+		newChecksum := hasher.Sum(nil)
+		if !bytes.Equal(lastNetworkChecksum, newChecksum) {
+			if len(lastNetworkChecksum) == 0 {
+				lastNetworkChecksum = newChecksum
+				continue
+			}
+			lastNetworkChecksum = newChecksum
+			atomic.StoreInt64(lastNetworkChange, time.Now().Unix())
+			log.Info("environment: network changed")
+			triggerNetworkChanged()
+		}
+	}
+}