package network import ( //Builtin "errors" "fmt" "math/rand" "net" "os" "strings" "time" //Internal "github.com/op/go-logging" //External "github.com/milosgajdos83/tenus" ) func BridgeInit(bridgeMAC string, nmIgnoreFile string, log *logging.Logger) (*HostNetwork, error) { if os.Getpid() == 1 { panic(errors.New("Cannot use netinit from child.")) } htn := &HostNetwork{ BridgeMAC: bridgeMAC, } if _, err := os.Stat(nmIgnoreFile); os.IsNotExist(err) { log.Warning("Warning! Network Manager may not properly configured to ignore the bridge interface! This may result in management conflicts!") } br, err := tenus.BridgeFromName(ozDefaultInterfaceBridge) if err != nil { log.Info("Bridge not found, attempting to create a new one") br, err = tenus.NewBridgeWithName(ozDefaultInterfaceBridge) if err != nil { return nil, fmt.Errorf("Unable to create bridge %+v", err) } } if err := htn.configureBridgeInterface(br, log); err != nil { return nil, err } brL := br.NetInterface() addrs, err := brL.Addrs() if err != nil { return nil, fmt.Errorf("Unable to get bridge interface addresses: %+v", err) } // Build the ip range which we will use for the network if err := htn.buildBridgeNetwork(addrs); err != nil { return nil, err } return htn, nil } func PrepareSandboxNetwork(htn *HostNetwork, log *logging.Logger) (*SandboxNetwork, error) { stn := new(SandboxNetwork) stn.VethHost = tenus.MakeNetInterfaceName(ozDefaultInterfacePrefix) stn.VethGuest = stn.VethHost + "1" stn.Gateway = htn.Gateway stn.Class = htn.Class // Allocate a new IP address stn.Ip = getFreshIP(htn.Min, htn.Max, log) if stn.Ip == "" { return nil, errors.New("Unable to acquire random IP") } return stn, nil } func NetInit(stn *SandboxNetwork, htn *HostNetwork, childPid int, log *logging.Logger) error { if os.Getpid() == 1 { panic(errors.New("Cannot use netSetup from child.")) } // Seed random number generator (poorly but we're not doing crypto) rand.Seed(time.Now().Unix() ^ int64((os.Getpid() + childPid))) log.Info("Configuring host veth pair '%s' with: %s", stn.VethHost, stn.Ip+"/"+htn.Class) // Fetch the bridge from the ifname br, err := tenus.BridgeFromName(ozDefaultInterfaceBridge) if err != nil { return fmt.Errorf("Unable to attach to bridge interface %, %s.", ozDefaultInterfaceBridge, err) } // Make sure the bridge is configured and the link is up // This really shouldn't be needed, but Network-Manager is a PITA // and even if you actualy ignore the interface there's a race // between the interface being created and setting it's hwaddr //if err := htn.configureBridgeInterface(br, log); err != nil { // return fmt.Errorf("Unable to reconfigure bridge: %+v", err) //} // Create the veth pair veth, err := tenus.NewVethPairWithOptions(stn.VethHost, tenus.VethOptions{PeerName: stn.VethGuest}) if err != nil { return fmt.Errorf("Unable to create veth pair %s, %s.", stn.VethHost, err) } // Fetch the newly created hostside veth vethIf, err := net.InterfaceByName(stn.VethHost) if err != nil { return fmt.Errorf("Unable to fetch veth pair %s, %s.", stn.VethHost, err) } // Add the host side veth to the bridge if err := br.AddSlaveIfc(vethIf); err != nil { return fmt.Errorf("Unable to add veth pair %s to bridge, %s.", stn.VethHost, err) } // Bring the host side veth interface up if err := veth.SetLinkUp(); err != nil { return fmt.Errorf("Unable to bring veth pair %s up, %s.", stn.VethHost, err) } // Assign the veth path to the namespace pid := childPid if err := veth.SetPeerLinkNsPid(pid); err != nil { return fmt.Errorf("Unable to add veth pair %s to namespace, %s.", stn.VethHost, err) } // Parse the ip/class into the the appropriate formats vethGuestIp, vethGuestIpNet, err := net.ParseCIDR(stn.Ip + "/" + htn.Class) if err != nil { return fmt.Errorf("Unable to parse ip %s, %s.", stn.Ip, err) } // Set interface address in the namespace if err := veth.SetPeerLinkNetInNs(pid, vethGuestIp, vethGuestIpNet, nil); err != nil { return fmt.Errorf("Unable to parse ip link in namespace, %s.", err) } return nil } func (stn *SandboxNetwork) Cleanup(log *logging.Logger) { if os.Getpid() == 1 { panic(errors.New("Cannot use Cleanup from child.")) } if _, err := net.InterfaceByName(stn.VethHost); err != nil { log.Info("No veth found to cleanup") return } tenus.DeleteLink(stn.VethHost) } func (htn *HostNetwork) configureBridgeInterface(br tenus.Bridger, log *logging.Logger) error { // Set the bridge mac address so it can be fucking ignored by Network-Manager. if htn.BridgeMAC != "" { if err := br.SetLinkMacAddress(htn.BridgeMAC); err != nil { return fmt.Errorf("Unable to set MAC address for gateway", err) } } if htn.Gateway == nil { // Lookup an empty ip range brIp, brIpNet, err := findEmptyRange() if err != nil { return fmt.Errorf("Could not find an ip range to assign to the bridge") } htn.Gateway = brIp htn.GatewayNet = brIpNet log.Info("Found available range: %+v", htn.GatewayNet.String()) } if err := br.SetLinkIp(htn.Gateway, htn.GatewayNet); err != nil { if os.IsExist(err) { log.Info("Bridge IP appears to be already assigned") } else { return fmt.Errorf("Unable to set gateway IP", err) } } // Bridge the interface up if err := br.SetLinkUp(); err != nil { return fmt.Errorf("Unable to bring bridge '%+v' up: %+v", ozDefaultInterfaceBridge, err) } return nil } func (htn *HostNetwork) buildBridgeNetwork(addrs []net.Addr) error { // Try to build the network config from the bridge's address addrIndex := -1 for i, addr := range addrs { bIP, brIP, _ := net.ParseCIDR(addr.String()) // Discard IPv6 (TODO...) if bIP.To4() != nil { addrIndex = i bMask := []byte(brIP.Mask) htn.Netmask = net.IPv4(bMask[0], bMask[1], bMask[2], bMask[3]) htn.Gateway = net.ParseIP(strings.Split(addr.String(), "/")[0]) htn.Class = strings.Split(addr.String(), "/")[1] htn.Broadcast = net_getbroadcast(bIP, brIP.Mask) htn.Min = inet_aton(bIP) htn.Min++ htn.Max = inet_aton(htn.Broadcast) htn.Max-- break } } if addrIndex < 0 { return errors.New("Could not find IPv4 for bridge interface") } return nil } // Look at all the assigned IP address and try to find an available range // Returns a ip range in the CIDR form if found or an empty string func findEmptyRange() (net.IP, *net.IPNet, error) { type localNet struct { min uint64 max uint64 } var ( localNets []localNet availableRange string ) // List all the available interfaces and their addresses // and calulate their network's min and max values ifs, _ := net.Interfaces() for _, netif := range ifs { // Disable loopback and our bridge if netif.Name == ozDefaultInterfaceBridge || strings.HasPrefix(netif.Name, "lo") { continue } // Go through each address on the interface addrs, _ := netif.Addrs() for _, addr := range addrs { bIP, brIP, _ := net.ParseCIDR(addr.String()) // Discard non IPv4 addresses if bIP.To4() != nil { min := inet_aton(brIP.IP) min++ max := inet_aton(net_getbroadcast(bIP, brIP.Mask)) max-- localNets = append(localNets, localNet{min: min, max: max}) } } } // Go through the list of private network ranges and // look for one in which we cannot find a local network for _, ipRange := range privateNetworkRanges { bIP, brIP, err := net.ParseCIDR(ipRange) if err != nil { continue } bMin := inet_aton(bIP) bMax := inet_aton(net_getbroadcast(bIP, brIP.Mask)) alreadyUsed := false for _, add := range localNets { if add.min >= bMin && add.min < bMax && add.max > bMin && add.max <= bMax { alreadyUsed = true break } } // If the range is available, grab a small slice if alreadyUsed == false { bRange := bMax - bMin if bRange > 0xFF { bMin = bMax - 0xFE } // XXX availableRange = inet_ntoa(bMin).String() + "/24" return net.ParseCIDR(availableRange) } } return nil, nil, errors.New("Could not find an available range") }