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Refactor port allocator to not have ANY global state

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Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby 2015-03-30 17:14:46 -07:00
parent e2d96d4304
commit 43a50b0618
2 changed files with 73 additions and 91 deletions
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139
daemon/networkdriver/portallocator/portallocator.go
View file

@ -16,59 +16,14 @@ const (
DefaultPortRangeEnd = 65535
)
var (
beginPortRange = DefaultPortRangeStart
endPortRange = DefaultPortRangeEnd
)
type portMap struct {
p map[int]struct{}
last int
}
func newPortMap() *portMap {
return &portMap{
p: map[int]struct{}{},
last: endPortRange,
}
}
type protoMap map[string]*portMap
func newProtoMap() protoMap {
return protoMap{
"tcp": newPortMap(),
"udp": newPortMap(),
}
}
type ipMapping map[string]protoMap
var (
ErrAllPortsAllocated = errors.New("all ports are allocated")
ErrUnknownProtocol = errors.New("unknown protocol")
defaultIP = net.ParseIP("0.0.0.0")
)
var (
defaultIP = net.ParseIP("0.0.0.0")
DefaultPortAllocator = New()
RequestPort = DefaultPortAllocator.RequestPort
ReleasePort = DefaultPortAllocator.ReleasePort
ReleaseAll = DefaultPortAllocator.ReleaseAll
)
type PortAllocator struct {
mutex sync.Mutex
ipMap ipMapping
}
func New() *PortAllocator {
return &PortAllocator{
ipMap: ipMapping{},
}
}
type ErrPortAlreadyAllocated struct {
ip string
port int
@ -81,32 +36,6 @@ func NewErrPortAlreadyAllocated(ip string, port int) ErrPortAlreadyAllocated {
}
}
func init() {
const portRangeKernelParam = "/proc/sys/net/ipv4/ip_local_port_range"
portRangeFallback := fmt.Sprintf("using fallback port range %d-%d", beginPortRange, endPortRange)
file, err := os.Open(portRangeKernelParam)
if err != nil {
logrus.Warnf("port allocator - %s due to error: %v", portRangeFallback, err)
return
}
var start, end int
n, err := fmt.Fscanf(bufio.NewReader(file), "%d\t%d", &start, &end)
if n != 2 || err != nil {
if err == nil {
err = fmt.Errorf("unexpected count of parsed numbers (%d)", n)
}
logrus.Errorf("port allocator - failed to parse system ephemeral port range from %s - %s: %v", portRangeKernelParam, portRangeFallback, err)
return
}
beginPortRange = start
endPortRange = end
}
func PortRange() (int, int) {
return beginPortRange, endPortRange
}
func (e ErrPortAlreadyAllocated) IP() string {
return e.ip
}
@ -123,6 +52,51 @@ func (e ErrPortAlreadyAllocated) Error() string {
return fmt.Sprintf("Bind for %s:%d failed: port is already allocated", e.ip, e.port)
}
type (
PortAllocator struct {
mutex sync.Mutex
ipMap ipMapping
Begin int
End int
}
portMap struct {
p map[int]struct{}
begin, end int
last int
}
protoMap map[string]*portMap
)
func New() *PortAllocator {
start, end, err := getDynamicPortRange()
if err != nil {
logrus.Warn(err)
start, end = DefaultPortRangeStart, DefaultPortRangeEnd
}
return &PortAllocator{
ipMap: ipMapping{},
Begin: start,
End: end,
}
}
func getDynamicPortRange() (start int, end int, err error) {
const portRangeKernelParam = "/proc/sys/net/ipv4/ip_local_port_range"
portRangeFallback := fmt.Sprintf("using fallback port range %d-%d", DefaultPortRangeStart, DefaultPortRangeEnd)
file, err := os.Open(portRangeKernelParam)
if err != nil {
return 0, 0, fmt.Errorf("port allocator - %s due to error: %v", portRangeFallback, err)
}
n, err := fmt.Fscanf(bufio.NewReader(file), "%d\t%d", &start, &end)
if n != 2 || err != nil {
if err == nil {
err = fmt.Errorf("unexpected count of parsed numbers (%d)", n)
}
return 0, 0, fmt.Errorf("port allocator - failed to parse system ephemeral port range from %s - %s: %v", portRangeKernelParam, portRangeFallback, err)
}
return start, end, nil
}
// RequestPort requests new port from global ports pool for specified ip and proto.
// If port is 0 it returns first free port. Otherwise it cheks port availability
// in pool and return that port or error if port is already busy.
@ -140,7 +114,11 @@ func (p *PortAllocator) RequestPort(ip net.IP, proto string, port int) (int, err
ipstr := ip.String()
protomap, ok := p.ipMap[ipstr]
if !ok {
protomap = newProtoMap()
protomap = protoMap{
"tcp": p.newPortMap(),
"udp": p.newPortMap(),
}
p.ipMap[ipstr] = protomap
}
mapping := protomap[proto]
@ -175,6 +153,15 @@ func (p *PortAllocator) ReleasePort(ip net.IP, proto string, port int) error {
return nil
}
func (p *PortAllocator) newPortMap() *portMap {
return &portMap{
p: map[int]struct{}{},
begin: p.Begin,
end: p.End,
last: p.End,
}
}
// ReleaseAll releases all ports for all ips.
func (p *PortAllocator) ReleaseAll() error {
p.mutex.Lock()
@ -185,10 +172,10 @@ func (p *PortAllocator) ReleaseAll() error {
func (pm *portMap) findPort() (int, error) {
port := pm.last
for i := 0; i <= endPortRange-beginPortRange; i++ {
for i := 0; i <= pm.end-pm.begin; i++ {
port++
if port > endPortRange {
port = beginPortRange
if port > pm.end {
port = pm.begin
}
if _, ok := pm.p[port]; !ok {

25
daemon/networkdriver/portallocator/portallocator_test.go
View file

@ -5,11 +5,6 @@ import (
"testing"
)
func init() {
beginPortRange = DefaultPortRangeStart
endPortRange = DefaultPortRangeEnd
}
func TestRequestNewPort(t *testing.T) {
p := New()
@ -18,7 +13,7 @@ func TestRequestNewPort(t *testing.T) {
t.Fatal(err)
}
if expected := beginPortRange; port != expected {
if expected := p.Begin; port != expected {
t.Fatalf("Expected port %d got %d", expected, port)
}
}
@ -101,13 +96,13 @@ func TestUnknowProtocol(t *testing.T) {
func TestAllocateAllPorts(t *testing.T) {
p := New()
for i := 0; i <= endPortRange-beginPortRange; i++ {
for i := 0; i <= p.End-p.Begin; i++ {
port, err := p.RequestPort(defaultIP, "tcp", 0)
if err != nil {
t.Fatal(err)
}
if expected := beginPortRange + i; port != expected {
if expected := p.Begin + i; port != expected {
t.Fatalf("Expected port %d got %d", expected, port)
}
}
@ -122,7 +117,7 @@ func TestAllocateAllPorts(t *testing.T) {
}
// release a port in the middle and ensure we get another tcp port
port := beginPortRange + 5
port := p.Begin + 5
if err := p.ReleasePort(defaultIP, "tcp", port); err != nil {
t.Fatal(err)
}
@ -152,13 +147,13 @@ func BenchmarkAllocatePorts(b *testing.B) {
p := New()
for i := 0; i < b.N; i++ {
for i := 0; i <= endPortRange-beginPortRange; i++ {
for i := 0; i <= p.End-p.Begin; i++ {
port, err := p.RequestPort(defaultIP, "tcp", 0)
if err != nil {
b.Fatal(err)
}
if expected := beginPortRange + i; port != expected {
if expected := p.Begin + i; port != expected {
b.Fatalf("Expected port %d got %d", expected, port)
}
}
@ -230,15 +225,15 @@ func TestPortAllocation(t *testing.T) {
func TestNoDuplicateBPR(t *testing.T) {
p := New()
if port, err := p.RequestPort(defaultIP, "tcp", beginPortRange); err != nil {
if port, err := p.RequestPort(defaultIP, "tcp", p.Begin); err != nil {
t.Fatal(err)
} else if port != beginPortRange {
t.Fatalf("Expected port %d got %d", beginPortRange, port)
} else if port != p.Begin {
t.Fatalf("Expected port %d got %d", p.Begin, port)
}
if port, err := p.RequestPort(defaultIP, "tcp", 0); err != nil {
t.Fatal(err)
} else if port == beginPortRange {
} else if port == p.Begin {
t.Fatalf("Acquire(0) allocated the same port twice: %d", port)
}
}