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-rw-r--r--pkg/tcpip/ports/ports.go49
-rw-r--r--pkg/tcpip/ports/ports_test.go56
-rw-r--r--pkg/tcpip/stack/BUILD1
-rw-r--r--pkg/tcpip/stack/stack.go25
-rw-r--r--pkg/tcpip/transport/tcp/BUILD1
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go17
6 files changed, 143 insertions, 6 deletions
diff --git a/pkg/tcpip/ports/ports.go b/pkg/tcpip/ports/ports.go
index 40e202717..30cea8996 100644
--- a/pkg/tcpip/ports/ports.go
+++ b/pkg/tcpip/ports/ports.go
@@ -19,6 +19,7 @@ import (
"math"
"math/rand"
"sync"
+ "sync/atomic"
"gvisor.dev/gvisor/pkg/tcpip"
)
@@ -27,6 +28,10 @@ const (
// FirstEphemeral is the first ephemeral port.
FirstEphemeral = 16000
+ // numEphemeralPorts it the mnumber of available ephemeral ports to
+ // Netstack.
+ numEphemeralPorts = math.MaxUint16 - FirstEphemeral + 1
+
anyIPAddress tcpip.Address = ""
)
@@ -40,6 +45,13 @@ type portDescriptor struct {
type PortManager struct {
mu sync.RWMutex
allocatedPorts map[portDescriptor]bindAddresses
+
+ // hint is used to pick ports ephemeral ports in a stable order for
+ // a given port offset.
+ //
+ // hint must be accessed using the portHint/incPortHint helpers.
+ // TODO(gvisor.dev/issue/940): S/R this field.
+ hint uint32
}
type portNode struct {
@@ -130,11 +142,40 @@ func NewPortManager() *PortManager {
// is suitable for its needs, and stopping when a port is found or an error
// occurs.
func (s *PortManager) PickEphemeralPort(testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) {
- count := uint16(math.MaxUint16 - FirstEphemeral + 1)
- offset := uint16(rand.Int31n(int32(count)))
+ offset := uint32(rand.Int31n(numEphemeralPorts))
+ return s.pickEphemeralPort(offset, numEphemeralPorts, testPort)
+}
+
+// portHint atomically reads and returns the s.hint value.
+func (s *PortManager) portHint() uint32 {
+ return atomic.LoadUint32(&s.hint)
+}
+
+// incPortHint atomically increments s.hint by 1.
+func (s *PortManager) incPortHint() {
+ atomic.AddUint32(&s.hint, 1)
+}
+
+// PickEphemeralPortStable starts at the specified offset + s.portHint and
+// iterates over all ephemeral ports, allowing the caller to decide whether a
+// given port is suitable for its needs and stopping when a port is found or an
+// error occurs.
+func (s *PortManager) PickEphemeralPortStable(offset uint32, testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) {
+ p, err := s.pickEphemeralPort(s.portHint()+offset, numEphemeralPorts, testPort)
+ if err == nil {
+ s.incPortHint()
+ }
+ return p, err
+
+}
- for i := uint16(0); i < count; i++ {
- port = FirstEphemeral + (offset+i)%count
+// pickEphemeralPort starts at the offset specified from the FirstEphemeral port
+// and iterates over the number of ports specified by count and allows the
+// caller to decide whether a given port is suitable for its needs, and stopping
+// when a port is found or an error occurs.
+func (s *PortManager) pickEphemeralPort(offset, count uint32, testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) {
+ for i := uint32(0); i < count; i++ {
+ port = uint16(FirstEphemeral + (offset+i)%count)
ok, err := testPort(port)
if err != nil {
return 0, err
diff --git a/pkg/tcpip/ports/ports_test.go b/pkg/tcpip/ports/ports_test.go
index a67e283f1..19f4833fc 100644
--- a/pkg/tcpip/ports/ports_test.go
+++ b/pkg/tcpip/ports/ports_test.go
@@ -15,6 +15,7 @@
package ports
import (
+ "math/rand"
"testing"
"gvisor.dev/gvisor/pkg/tcpip"
@@ -232,7 +233,6 @@ func TestPortReservation(t *testing.T) {
}
func TestPickEphemeralPort(t *testing.T) {
- pm := NewPortManager()
customErr := &tcpip.Error{}
for _, test := range []struct {
name string
@@ -276,9 +276,63 @@ func TestPickEphemeralPort(t *testing.T) {
},
} {
t.Run(test.name, func(t *testing.T) {
+ pm := NewPortManager()
if port, err := pm.PickEphemeralPort(test.f); port != test.wantPort || err != test.wantErr {
t.Errorf("PickEphemeralPort(..) = (port %d, err %v); want (port %d, err %v)", port, err, test.wantPort, test.wantErr)
}
})
}
}
+
+func TestPickEphemeralPortStable(t *testing.T) {
+ customErr := &tcpip.Error{}
+ for _, test := range []struct {
+ name string
+ f func(port uint16) (bool, *tcpip.Error)
+ wantErr *tcpip.Error
+ wantPort uint16
+ }{
+ {
+ name: "no-port-available",
+ f: func(port uint16) (bool, *tcpip.Error) {
+ return false, nil
+ },
+ wantErr: tcpip.ErrNoPortAvailable,
+ },
+ {
+ name: "port-tester-error",
+ f: func(port uint16) (bool, *tcpip.Error) {
+ return false, customErr
+ },
+ wantErr: customErr,
+ },
+ {
+ name: "only-port-16042-available",
+ f: func(port uint16) (bool, *tcpip.Error) {
+ if port == FirstEphemeral+42 {
+ return true, nil
+ }
+ return false, nil
+ },
+ wantPort: FirstEphemeral + 42,
+ },
+ {
+ name: "only-port-under-16000-available",
+ f: func(port uint16) (bool, *tcpip.Error) {
+ if port < FirstEphemeral {
+ return true, nil
+ }
+ return false, nil
+ },
+ wantErr: tcpip.ErrNoPortAvailable,
+ },
+ } {
+ t.Run(test.name, func(t *testing.T) {
+ pm := NewPortManager()
+ portOffset := uint32(rand.Int31n(int32(numEphemeralPorts)))
+ if port, err := pm.PickEphemeralPortStable(portOffset, test.f); port != test.wantPort || err != test.wantErr {
+ t.Errorf("PickEphemeralPort(..) = (port %d, err %v); want (port %d, err %v)", port, err, test.wantPort, test.wantErr)
+ }
+ })
+ }
+}
diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 3842f1f7d..baf88bfab 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -36,6 +36,7 @@ go_library(
],
deps = [
"//pkg/ilist",
+ "//pkg/rand",
"//pkg/sleep",
"//pkg/tcpip",
"//pkg/tcpip/buffer",
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 6a8079823..90c2cf1be 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -20,10 +20,12 @@
package stack
import (
+ "encoding/binary"
"sync"
"time"
"golang.org/x/time/rate"
+ "gvisor.dev/gvisor/pkg/rand"
"gvisor.dev/gvisor/pkg/sleep"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -388,6 +390,12 @@ type Stack struct {
// icmpRateLimiter is a global rate limiter for all ICMP messages generated
// by the stack.
icmpRateLimiter *ICMPRateLimiter
+
+ // portSeed is a one-time random value initialized at stack startup
+ // and is used to seed the TCP port picking on active connections
+ //
+ // TODO(gvisor.dev/issues/940): S/R this field.
+ portSeed uint32
}
// Options contains optional Stack configuration.
@@ -440,6 +448,7 @@ func New(opts Options) *Stack {
stats: opts.Stats.FillIn(),
handleLocal: opts.HandleLocal,
icmpRateLimiter: NewICMPRateLimiter(),
+ portSeed: generateRandUint32(),
}
// Add specified network protocols.
@@ -1197,3 +1206,19 @@ func (s *Stack) SetICMPBurst(burst int) {
func (s *Stack) AllowICMPMessage() bool {
return s.icmpRateLimiter.Allow()
}
+
+// PortSeed returns a 32 bit value that can be used as a seed value for port
+// picking.
+//
+// NOTE: The seed is generated once during stack initialization only.
+func (s *Stack) PortSeed() uint32 {
+ return s.portSeed
+}
+
+func generateRandUint32() uint32 {
+ b := make([]byte, 4)
+ if _, err := rand.Read(b); err != nil {
+ panic(err)
+ }
+ return binary.LittleEndian.Uint32(b)
+}
diff --git a/pkg/tcpip/transport/tcp/BUILD b/pkg/tcpip/transport/tcp/BUILD
index 39a839ab7..a42e1f4a2 100644
--- a/pkg/tcpip/transport/tcp/BUILD
+++ b/pkg/tcpip/transport/tcp/BUILD
@@ -49,6 +49,7 @@ go_library(
"//pkg/sleep",
"//pkg/tcpip",
"//pkg/tcpip/buffer",
+ "//pkg/tcpip/hash/jenkins",
"//pkg/tcpip/header",
"//pkg/tcpip/iptables",
"//pkg/tcpip/seqnum",
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index a1cd0d481..f9d5e0085 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -15,6 +15,7 @@
package tcp
import (
+ "encoding/binary"
"fmt"
"math"
"strings"
@@ -26,6 +27,7 @@ import (
"gvisor.dev/gvisor/pkg/sleep"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
+ "gvisor.dev/gvisor/pkg/tcpip/hash/jenkins"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/iptables"
"gvisor.dev/gvisor/pkg/tcpip/seqnum"
@@ -1504,7 +1506,20 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) (er
// address/port for both local and remote (otherwise this
// endpoint would be trying to connect to itself).
sameAddr := e.id.LocalAddress == e.id.RemoteAddress
- if _, err := e.stack.PickEphemeralPort(func(p uint16) (bool, *tcpip.Error) {
+
+ // Calculate a port offset based on the destination IP/port and
+ // src IP to ensure that for a given tuple (srcIP, destIP,
+ // destPort) the offset used as a starting point is the same to
+ // ensure that we can cycle through the port space effectively.
+ h := jenkins.Sum32(e.stack.PortSeed())
+ h.Write([]byte(e.id.LocalAddress))
+ h.Write([]byte(e.id.RemoteAddress))
+ portBuf := make([]byte, 2)
+ binary.LittleEndian.PutUint16(portBuf, e.id.RemotePort)
+ h.Write(portBuf)
+ portOffset := h.Sum32()
+
+ if _, err := e.stack.PickEphemeralPortStable(portOffset, func(p uint16) (bool, *tcpip.Error) {
if sameAddr && p == e.id.RemotePort {
return false, nil
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 12:28:59 +0000