1 files changed, 31 insertions, 52 deletions

diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 18d1704a5..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.
@@ -1033,73 +1042,27 @@ func (s *Stack) RemoveWaker(nicid tcpip.NICID, addr tcpip.Address, waker *sleep.
 // transport dispatcher. Received packets that match the provided id will be
 // delivered to the given endpoint; specifying a nic is optional, but
 // nic-specific IDs have precedence over global ones.
-func (s *Stack) RegisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, reusePort bool) *tcpip.Error {
-	if nicID == 0 {
-		return s.demux.registerEndpoint(netProtos, protocol, id, ep, reusePort)
-	}
-
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	nic := s.nics[nicID]
-	if nic == nil {
-		return tcpip.ErrUnknownNICID
-	}
-
-	return nic.demux.registerEndpoint(netProtos, protocol, id, ep, reusePort)
+func (s *Stack) RegisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, reusePort bool, bindToDevice tcpip.NICID) *tcpip.Error {
+	return s.demux.registerEndpoint(netProtos, protocol, id, ep, reusePort, bindToDevice)
 }
 
 // UnregisterTransportEndpoint removes the endpoint with the given id from the
 // stack transport dispatcher.
-func (s *Stack) UnregisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint) {
-	if nicID == 0 {
-		s.demux.unregisterEndpoint(netProtos, protocol, id, ep)
-		return
-	}
-
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	nic := s.nics[nicID]
-	if nic != nil {
-		nic.demux.unregisterEndpoint(netProtos, protocol, id, ep)
-	}
+func (s *Stack) UnregisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, bindToDevice tcpip.NICID) {
+	s.demux.unregisterEndpoint(netProtos, protocol, id, ep, bindToDevice)
 }
 
 // RegisterRawTransportEndpoint registers the given endpoint with the stack
 // transport dispatcher. Received packets that match the provided transport
 // protocol will be delivered to the given endpoint.
 func (s *Stack) RegisterRawTransportEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, ep RawTransportEndpoint) *tcpip.Error {
-	if nicID == 0 {
-		return s.demux.registerRawEndpoint(netProto, transProto, ep)
-	}
-
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	nic := s.nics[nicID]
-	if nic == nil {
-		return tcpip.ErrUnknownNICID
-	}
-
-	return nic.demux.registerRawEndpoint(netProto, transProto, ep)
+	return s.demux.registerRawEndpoint(netProto, transProto, ep)
 }
 
 // UnregisterRawTransportEndpoint removes the endpoint for the transport
 // protocol from the stack transport dispatcher.
 func (s *Stack) UnregisterRawTransportEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, ep RawTransportEndpoint) {
-	if nicID == 0 {
-		s.demux.unregisterRawEndpoint(netProto, transProto, ep)
-		return
-	}
-
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	nic := s.nics[nicID]
-	if nic != nil {
-		nic.demux.unregisterRawEndpoint(netProto, transProto, ep)
-	}
+	s.demux.unregisterRawEndpoint(netProto, transProto, ep)
 }
 
 // RegisterRestoredEndpoint records e as an endpoint that has been restored on
@@ -1243,3 +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)
+}