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subgraph-oz/network/daemon.go

310 lines
7.9 KiB

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")
}