// Assumes RWLock is held
func (subnet *Subnet) getFreeIP() (*net.IP, bool) {
bit, success := firstClearBit(subnet.ActiveBits)
if success {
subnet.ActiveBits.Set(bit)
ip := dhcp.IPAdd(subnet.ActiveStart, int(bit))
return &ip, true
}
// Free invalid or expired leases
save_me := false
now := time.Now()
for k, lease := range subnet.Leases {
if now.After(lease.ExpireTime) {
if dhcp.IPInRange(subnet.ActiveStart, subnet.ActiveEnd, lease.Ip) {
subnet.ActiveBits.Clear(uint(dhcp.IPRange(lease.Ip, subnet.ActiveStart) - 1))
}
delete(subnet.Leases, k)
save_me = true
}
}
bit, success = firstClearBit(subnet.ActiveBits)
if success {
subnet.ActiveBits.Set(bit)
ip := dhcp.IPAdd(subnet.ActiveStart, int(bit))
return &ip, true
}
// We got nothin'
return nil, save_me
}
func newSubnet(dt *DataTracker, name, subnet string) (s *Subnet) {
_, theNet, _ := net.ParseCIDR(subnet)
s = NewSubnet()
s.Name = name
s.Subnet = &MyIPNet{theNet}
s.ActiveStart = dhcp.IPAdd(theNet.IP, 5)
s.ActiveEnd = dhcp.IPAdd(theNet.IP, 25)
return
}
func (d *DHCPService) getIPFromPool() net.IP {
// locate an unused IP address (can this be more efficient? yes! FIXME)
// TODO: Create a channel and spawn a goproc with something like this function to feed it; then have the server pull addresses from that channel
for ip := dhcp4.IPAdd(d.guestPool.IP, 1); d.guestPool.Contains(ip); ip = dhcp4.IPAdd(ip, 1) {
//log.Println(ip.String())
if !d.db.HasIP(ip) { // this means that the IP is not already occupied
return ip
}
}
return nil
}
// Assign assigns an ip to the node with the specified nic
// Will use etcd machines records as LeasePool
// part of DHCPDataSource interface implementation
func (ds *EtcdDataSource) Assign(nic string) (net.IP, error) {
ds.lockDHCPAssign()
defer ds.unlockdhcpAssign()
// TODO: first try to retrieve the machine, if exists (for performance)
assignedIPs := make(map[string]bool)
//find by Mac
machines, _ := ds.Machines()
for _, node := range machines {
if node.Mac().String() == nic {
ip, _ := node.IP()
ds.store(node, ip)
return ip, nil
}
nodeIP, _ := node.IP()
assignedIPs[nodeIP.String()] = true
}
//find an unused ip
for i := 0; i < ds.LeaseRange(); i++ {
ip := dhcp4.IPAdd(ds.LeaseStart(), i)
if _, exists := assignedIPs[ip.String()]; !exists {
macAddress, _ := net.ParseMAC(nic)
ds.CreateMachine(macAddress, ip)
return ip, nil
}
}
//use an expired ip
//not implemented
logging.Log(debugTag, "DHCP pool is full")
return nil, nil
}
func (h *DHCPHandler) ServeDHCP(p dhcp.Packet, msgType dhcp.MessageType, options dhcp.Options) (d dhcp.Packet) {
switch msgType {
case dhcp.Discover:
free, nic := -1, p.CHAddr().String()
for i, v := range h.leases { // Find previous lease
if v.nic == nic {
free = i
goto reply
}
}
if free = h.freeLease(); free == -1 {
return
}
reply:
return dhcp.ReplyPacket(p, dhcp.Offer, h.ip, dhcp.IPAdd(h.start, free), h.leaseDuration,
h.options.SelectOrderOrAll(options[dhcp.OptionParameterRequestList]))
case dhcp.Request:
if server, ok := options[dhcp.OptionServerIdentifier]; ok && !net.IP(server).Equal(h.ip) {
return nil // Message not for this dhcp server
}
reqIP := net.IP(options[dhcp.OptionRequestedIPAddress])
if reqIP == nil {
reqIP = net.IP(p.CIAddr())
}
if len(reqIP) == 4 && !reqIP.Equal(net.IPv4zero) {
if leaseNum := dhcp.IPRange(h.start, reqIP) - 1; leaseNum >= 0 && leaseNum < h.leaseRange {
if l, exists := h.leases[leaseNum]; !exists || l.nic == p.CHAddr().String() {
h.leases[leaseNum] = lease{nic: p.CHAddr().String(), expiry: time.Now().Add(h.leaseDuration)}
return dhcp.ReplyPacket(p, dhcp.ACK, h.ip, net.IP(options[dhcp.OptionRequestedIPAddress]), h.leaseDuration,
h.options.SelectOrderOrAll(options[dhcp.OptionParameterRequestList]))
}
}
}
return dhcp.ReplyPacket(p, dhcp.NAK, h.ip, nil, 0, nil)
case dhcp.Release, dhcp.Decline:
nic := p.CHAddr().String()
for i, v := range h.leases {
if v.nic == nic {
delete(h.leases, i)
break
}
}
}
return nil
}
func (h *DHCPHandler) ServeDHCP(p dhcp.Packet, msgType dhcp.MessageType, options dhcp.Options) (d dhcp.Packet) {
switch msgType {
case dhcp.Discover:
log.Info("discover received")
fallthrough
case dhcp.Request:
if msgType == dhcp.Request {
log.Info("request received")
}
hwaddr := p.CHAddr().String()
var msg dhcp.MessageType
if msgType == dhcp.Discover {
msg = dhcp.Offer
} else if msgType == dhcp.Request {
msg = dhcp.ACK
}
if _, ok := h.leases[hwaddr]; ok {
log.Infof("Replying with existing lease %s", h.leases[hwaddr].String())
return dhcp.ReplyPacket(p, msg, h.myIP, h.leases[hwaddr], time.Hour, nil)
} else {
log.Info("new interface; attempting to allocate ip")
h.allocatorMutex.Lock()
if h.latest == nil {
h.latest = h.allocator.IP
}
h.latest = dhcp.IPAdd(h.latest, 1)
h.leases[hwaddr] = h.latest.To4()
h.allocatorMutex.Unlock()
log.Infof("Replying with address %s for hardware addr %s", h.leases[hwaddr].String(), hwaddr)
return dhcp.ReplyPacket(p, msg, h.myIP, h.leases[hwaddr], time.Hour, nil)
}
}
return nil
}
// Assign will find an IP for the specified nic
func (p *LeasePool) Assign(nic string) (net.IP, error) {
p.assignLock.Lock()
defer p.assignLock.Unlock()
leases, err := p.Leases()
if err != nil {
return nil, err
}
// try to find by mac address
for _, lease := range leases {
if lease.Nic == nic {
p.Store(newLease(nic, lease.IP, p.expireDuration, &lease.FirstAssigned))
return lease.IP, nil
}
}
// find an unseen ip
for i := 0; i < p.rangeLen; i++ {
ip := dhcp4.IPAdd(p.startIP, i)
_, exists := leases[ip.String()]
if !exists {
err := p.Store(newLease(nic, ip, p.expireDuration, nil))
if err != nil {
return nil, err
}
return ip, nil
}
}
// find an expired ip
now := time.Now()
for _, lease := range leases {
if lease.ExpireTime.Before(now) {
p.Store(newLease(nic, lease.IP, p.expireDuration, nil))
return lease.IP, nil
}
}
return nil, ErrLeasePoolIsFull
}
func (m *etcdMachineInterface) store(machine *Machine) error {
if machine.Type == 0 {
if machine.IP == nil {
machine.Type = MTNormal
} else {
machine.Type = MTStatic
}
}
m.etcdDS.dhcpAssignLock.Lock()
defer m.etcdDS.dhcpAssignLock.Unlock()
machineInterfaces, err := m.etcdDS.MachineInterfaces()
if err != nil {
return fmt.Errorf("error while getting the machine interfaces: %s", err)
}
ipToMac := make(map[string]net.HardwareAddr)
for _, mi := range machineInterfaces {
machine, err := mi.Machine(false, nil)
if err != nil {
return fmt.Errorf("error while getting the machine for (%s): %s",
mi.Mac().String(), err)
}
ipToMac[machine.IP.String()] = mi.Mac()
}
if machine.IP == nil {
// To avoid concurrency problems
// We expect rhis part to be triggered only through DHCP, so we expect
// IsMaster() to returns true
if err := m.etcdDS.IsMaster(); err != nil {
return fmt.Errorf(
"only the master instance is allowed to store machine info: %s",
err)
}
counter := len(ipToMac) % m.etcdDS.leaseRange
firstCandidateIP := dhcp4.IPAdd(m.etcdDS.leaseStart, counter) // kickstarted
candidateIP := net.IPv4(
firstCandidateIP[0], firstCandidateIP[1],
firstCandidateIP[2], firstCandidateIP[3]) // copy
for _, isAssigned := ipToMac[candidateIP.String()]; isAssigned; {
candidateIP = dhcp4.IPAdd(candidateIP, 1)
counter++
if counter == m.etcdDS.leaseRange {
candidateIP = m.etcdDS.leaseStart
counter = 0
}
if firstCandidateIP.Equal(candidateIP) {
break
}
}
if _, isAssigned := ipToMac[candidateIP.String()]; isAssigned {
return fmt.Errorf("no unassigned IP was found")
}
machine.IP = candidateIP
} else {
if m, isAssigned := ipToMac[machine.IP.String()]; isAssigned {
return fmt.Errorf(
"the requested IP(%s) is already assigned to another machine(%s)",
machine.IP.String(), m.String())
}
}
jsonedStats, err := json.Marshal(*machine)
if err != nil {
return fmt.Errorf("error while marshaling the machine: %s", err)
}
err = m.selfSet("_machine", string(jsonedStats))
if err != nil {
return fmt.Errorf("error while setting the marshaled machine: %s", err)
}
return nil
}