gocage/cmd/jailhost.go

package cmd

import (
	"fmt"
	"net"
	"regexp"
	"strconv"
	"strings"
	"io/ioutil"
	"golang.org/x/net/route"
)

var defaultRoute4 = [4]byte{0, 0, 0, 0}
var defaultRoute6 = [16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
var local6 = [16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}

func Inet4AddrToString(ip4 route.Inet4Addr) string {
	return fmt.Sprintf("%v.%v.%v.%v", ip4.IP[0], ip4.IP[1], ip4.IP[2], ip4.IP[3])
}

func Inet6AddrToString(ip6 route.Inet6Addr) string {
	return fmt.Sprintf("%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",
		ip6.IP[0], ip6.IP[1], ip6.IP[2], ip6.IP[3], ip6.IP[4], ip6.IP[5], ip6.IP[6], ip6.IP[7],
		ip6.IP[8], ip6.IP[9], ip6.IP[10], ip6.IP[11], ip6.IP[12], ip6.IP[13], ip6.IP[14], ip6.IP[15])
}

/*****************************************************************************
* Initialize default_interface, default_gatway4, default_gateway6
*****************************************************************************/
func (jh *JailHost) InitNetworkProperties() {
	rib, _ := route.FetchRIB(0, route.RIBTypeRoute, 0)
	messages, err := route.ParseRIB(route.RIBTypeRoute, rib)
	if err != nil {
		panic(err)
	}

	for _, message := range messages {
		route_message := message.(*route.RouteMessage)
		addresses := route_message.Addrs
		card_index := route_message.Index

		if addresses[0].Family() == 2 {
			var destination4, gateway4 *route.Inet4Addr
			ok := false

			if destination4, ok = addresses[0].(*route.Inet4Addr); !ok {
				continue
			}

			if gateway4, ok = addresses[1].(*route.Inet4Addr); !ok {
				continue
			}

			if destination4 == nil || gateway4 == nil {
				continue
			}

			if destination4.IP == defaultRoute4 {
				card, _ := net.InterfaceByIndex(card_index)
				//fmt.Printf("Default IPv4 gateway is %v on card %s\n", Inet4AddrToString(*gateway4), card.Name)
				jh.default_interface = card.Name
				jh.default_gateway4 = Inet4AddrToString(*gateway4)
			}
		} else if addresses[0].Family() == 28 {
			var destination6, gateway6 *route.Inet6Addr
			ok := false

			if destination6, ok = addresses[0].(*route.Inet6Addr); !ok {
				continue
			}

			if gateway6, ok = addresses[1].(*route.Inet6Addr); !ok {
				continue
			}

			if destination6 == nil || gateway6 == nil {
				continue
			}

			if destination6.IP == defaultRoute6 && gateway6.IP != local6 {
				card, _ := net.InterfaceByIndex(card_index)
				//fmt.Printf("Default IPv6 gateway is %v on card %s\n", Inet6AddrToString(*gateway6), card.Name)
				jh.default_interface = card.Name
				jh.default_gateway6 = Inet6AddrToString(*gateway6)
			}
		}
	}
}

func (jh *JailHost) GetDefaultInterface() string {
	if len(jh.default_interface) == 0 {
		jh.InitNetworkProperties()
	}
	return jh.default_interface
}

func (jh *JailHost) GetDefaultGateway4() string {
	if len(jh.default_gateway4) == 0 {
		jh.InitNetworkProperties()
	}
	return jh.default_gateway4
}

func (jh *JailHost) GetDefaultGateway6() string {
	if len(jh.default_gateway6) == 0 {
		jh.InitNetworkProperties()
	}
	return jh.default_gateway6
}

/*****************************************************************************
 * Get all network interfaces
 ****************************************************************************/
func (jh *JailHost) GetInterfaces() ([]string, error) {
	var names []string
	
	interfaces, err := net.Interfaces()
	if err != nil {
		return names, fmt.Errorf("Error listing network interfaces: %v", err)
	}
	for _, n := range interfaces {
		names = append(names, n.Name)
	}
	
	return names, nil
}

func (jh *JailHost) GetBridgeMTU(bridgeName string) (int, error) {
	bridge, err := net.InterfaceByName(bridgeName)
	if err != nil {
		return 0, err
	}
	
	return bridge.MTU, nil
}

/*****************************************************************************
 * Get all IPv4 currently in use on host
 ****************************************************************************/
func getHostInUseIPv4() ([]string, error) {
	var ips []string

	re := regexp.MustCompile(ifconfigipv4re)

	out, err := executeCommand("/sbin/ifconfig")
	if err != nil {
		return ips, fmt.Errorf("Error executing \"/sbin/ifconfig\": %s", err)
	}

	for _, line := range strings.Split(out, "\n") {
		if re.MatchString(line) {
			ips = append(ips, re.FindStringSubmatch(line)[1])
		}
	}

	return ips, nil
}

func getHostname() (string, error) {
	out, err := executeCommand("/bin/hostname")
	if err != nil {
		return "", fmt.Errorf("Error executing \"/bin/hostname\": %v", err)
	}
	
	return strings.Split(out, "\n")[0], nil
}

func getHostId() (string, error) {
	var content []byte
	var err     error
	// return empty string if file does not exist
	if content, err = ioutil.ReadFile("/etc/hostid"); err != nil {
		if strings.HasSuffix(err.Error(), "no such file or directory") {
			return "", nil
		}
		return "", err
	}
	
	return strings.Split(string(content), "\n")[0], nil
}

func getArch() (string, error) {
	out, err := executeCommand("/usr/bin/uname -p")
	if err != nil {
		return "", fmt.Errorf("Error executing \"/usr/bin/uname -p\": %v", err)
	}
	
	return strings.Split(out, "\n")[0], nil
}

func getFreeBSDVersion() (FreeBSDVersion, error) {
	var version FreeBSDVersion
	regex := `([0-9]{1,2})(\.)?([0-9]{1,2})?\-([^\-]*)(\-)?(p[0-9]{1,2})?`
	
	re := regexp.MustCompile(regex)
	
	out, err := executeCommand("/bin/freebsd-version")
	if err != nil {
		return version, fmt.Errorf("Error executing \"/bin/freebsd-version\": %v", err)
	}
	
	if re.MatchString(out) {
		version.major, err = strconv.Atoi(re.FindStringSubmatch(out)[1])
		if err != nil {
			return version, err
		}
		version.minor, err = strconv.Atoi(re.FindStringSubmatch(out)[3])
		if err != nil {
			return version, err
		}
		version.flavor = strings.Trim(re.FindStringSubmatch(out)[4], "\n")
		
		// Skip the 'p' starting patch level
		if len(re.FindStringSubmatch(out)[6]) > 0 {
			version.patchLevel, err = strconv.Atoi(re.FindStringSubmatch(out)[6][1:])
			if err != nil {
				return version, err
			}
		}
	}
	return version, nil
}

func NewJailHost() (JailHost, error) {
	var jh  JailHost
	var err error
	
	if jh.hostname, err = getHostname(); err != nil {
		return jh, err
	}
	if jh.arch, err = getArch(); err != nil {
		return jh, err
	}
	if jh.hostid, err = getHostId(); err != nil {
		return jh, err
	}
	if jh.version, err = getFreeBSDVersion(); err != nil {
		return jh, err
	}
	return jh, nil
}