github.com/mfpierre/corectl@v0.5.6/uuid2ip/uuid2ip.go (about)

     1  // Copyright 2015 - António Meireles  <antonio.meireles@reformi.st>
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  
    16  // Package uuid2ip is a simple interface to interact with xhyve's networking
    17  package uuid2ip
    18  
    19  /*
    20  #cgo CFLAGS: -framework Hypervisor -framework vmnet
    21  #cgo LDFLAGS: -framework Hypervisor -framework vmnet
    22  #include <stdlib.h>
    23  #include "uuid2ip.c"
    24  */
    25  import "C"
    26  import (
    27  	"fmt"
    28  	"io/ioutil"
    29  	"net"
    30  	"os"
    31  	"regexp"
    32  	"strings"
    33  	"unsafe"
    34  )
    35  
    36  // GuestMACfromUUID returns the MAC address that will assembled from the given
    37  // UUID by xhyve,  needs to be called before xhyve actual invocation
    38  func GuestMACfromUUID(uuid string) (mac string, err error) {
    39  	var (
    40  		hw    net.HardwareAddr
    41  		uuidC = C.CString(uuid)
    42  	)
    43  	mac = C.GoString(C.vmnet_get_mac_address_from_uuid(uuidC))
    44  	C.free(unsafe.Pointer(uuidC))
    45  	if mac == "" {
    46  		err = fmt.Errorf("Could not get a MAC address from %s", uuid)
    47  	} else if hw, err = net.ParseMAC(mac); err == nil {
    48  		mac = hw.String()
    49  	}
    50  	return
    51  }
    52  
    53  // GuestIPfromMAC returns the IP address that would be leased to the given MAC
    54  // address by xhyve, to be called after actual xhyve invocation
    55  func GuestIPfromMAC(mac string) (ip string, err error) {
    56  	var (
    57  		f          *os.File
    58  		allLeases  []byte
    59  		lastFound  string
    60  		leasesPath = "/var/db/dhcpd_leases"
    61  		ipAddrRe   = regexp.MustCompile(`^.*ip_address=(.+?)$`)
    62  		macAddrRe  = regexp.MustCompile(`^.*hw_address=1,(.+?)$`)
    63  	)
    64  
    65  	if f, err = os.Open(leasesPath); err != nil {
    66  		return
    67  	}
    68  	defer f.Close()
    69  
    70  	if allLeases, err = ioutil.ReadAll(f); err != nil {
    71  		return
    72  	}
    73  
    74  	for _, l := range strings.Split(string(allLeases), "\n") {
    75  		l = strings.TrimRight(l, "\r")
    76  
    77  		matches := ipAddrRe.FindStringSubmatch(l)
    78  		if matches != nil {
    79  			lastFound = matches[1]
    80  			continue
    81  		}
    82  
    83  		matches = macAddrRe.FindStringSubmatch(l)
    84  		// OSX's dhcp stores technically incorrect mac addr as it strips
    85  		// leading zeros from them, so we need to take that in consideration
    86  		// before checking match...
    87  		if matches != nil && strings.EqualFold(matches[1],
    88  			strings.TrimPrefix(strings.Replace(mac, ":0", ":", -1), "0")) {
    89  			return lastFound, nil
    90  		}
    91  	}
    92  	return ip, fmt.Errorf("%s isn't in ANY active DHCP lease (!)", mac)
    93  }