3 files changed, 32 insertions, 2 deletions
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index dce9a1652..91f25c132 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -105,6 +105,7 @@ type protocol struct {
 	moderateReceiveBuffer      bool
 	tcpLingerTimeout           time.Duration
 	tcpTimeWaitTimeout         time.Duration
+	minRTO                     time.Duration
 	dispatcher                 *dispatcher
 }
 
@@ -272,6 +273,15 @@ func (p *protocol) SetOption(option interface{}) *tcpip.Error {
 		p.mu.Unlock()
 		return nil
 
+	case tcpip.TCPMinRTOOption:
+		if v < 0 {
+			v = tcpip.TCPMinRTOOption(MinRTO)
+		}
+		p.mu.Lock()
+		p.minRTO = time.Duration(v)
+		p.mu.Unlock()
+		return nil
+
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}
@@ -334,6 +344,12 @@ func (p *protocol) Option(option interface{}) *tcpip.Error {
 		p.mu.RUnlock()
 		return nil
 
+	case *tcpip.TCPMinRTOOption:
+		p.mu.RLock()
+		*v = tcpip.TCPMinRTOOption(p.minRTO)
+		p.mu.RUnlock()
+		return nil
+
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}
@@ -359,5 +375,6 @@ func NewProtocol() stack.TransportProtocol {
 		tcpLingerTimeout:           DefaultTCPLingerTimeout,
 		tcpTimeWaitTimeout:         DefaultTCPTimeWaitTimeout,
 		dispatcher:                 newDispatcher(runtime.GOMAXPROCS(0)),
+		minRTO:                     MinRTO,
 	}
 }
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 6b7bac37d..d8cfe3115 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -15,6 +15,7 @@
 package tcp
 
 import (
+	"fmt"
 	"math"
 	"sync/atomic"
 	"time"
@@ -149,6 +150,9 @@ type sender struct {
 	rtt rtt
 	rto time.Duration
 
+	// minRTO is the minimum permitted value for sender.rto.
+	minRTO time.Duration
+
 	// maxPayloadSize is the maximum size of the payload of a given segment.
 	// It is initialized on demand.
 	maxPayloadSize int
@@ -260,6 +264,13 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
 	// etc.
 	s.ep.scoreboard = NewSACKScoreboard(uint16(s.maxPayloadSize), iss)
 
+	// Get Stack wide minRTO.
+	var v tcpip.TCPMinRTOOption
+	if err := ep.stack.TransportProtocolOption(ProtocolNumber, &v); err != nil {
+		panic(fmt.Sprintf("unable to get minRTO from stack: %s", err))
+	}
+	s.minRTO = time.Duration(v)
+
 	return s
 }
 
@@ -394,8 +405,8 @@ func (s *sender) updateRTO(rtt time.Duration) {
 
 	s.rto = s.rtt.srtt + 4*s.rtt.rttvar
 	s.rtt.Unlock()
-	if s.rto < MinRTO {
-		s.rto = MinRTO
+	if s.rto < s.minRTO {
+		s.rto = s.minRTO
 	}
 }
 
diff --git a/pkg/tcpip/transport/tcp/tcp_state_autogen.go b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
index b3cb5f986..5ac73e3b7 100755
--- a/pkg/tcpip/transport/tcp/tcp_state_autogen.go
+++ b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
@@ -374,6 +374,7 @@ func (x *sender) save(m state.Map) {
 	m.Save("writeList", &x.writeList)
 	m.Save("rtt", &x.rtt)
 	m.Save("rto", &x.rto)
+	m.Save("minRTO", &x.minRTO)
 	m.Save("maxPayloadSize", &x.maxPayloadSize)
 	m.Save("gso", &x.gso)
 	m.Save("sndWndScale", &x.sndWndScale)
@@ -399,6 +400,7 @@ func (x *sender) load(m state.Map) {
 	m.Load("writeList", &x.writeList)
 	m.Load("rtt", &x.rtt)
 	m.Load("rto", &x.rto)
+	m.Load("minRTO", &x.minRTO)
 	m.Load("maxPayloadSize", &x.maxPayloadSize)
 	m.Load("gso", &x.gso)
 	m.Load("sndWndScale", &x.sndWndScale)