tcp: change the limit of TCP_LINGER2

It was changed in the Linux kernel:

commit f0628c524fd188c3f9418e12478dfdfadacba815
Date:   Fri Apr 24 16:06:16 2020 +0800
net: Replace the limit of TCP_LINGER2 with TCP_FIN_TIMEOUT_MAX
PiperOrigin-RevId: 325493859

3 files changed, 7 insertions, 10 deletions

diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 39ea38fe6..b8b52b03d 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1777,15 +1777,8 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 			// Same as effectively disabling TCPLinger timeout.
 			v = 0
 		}
-		var stkTCPLingerTimeout tcpip.TCPLingerTimeoutOption
-		if err := e.stack.TransportProtocolOption(header.TCPProtocolNumber, &stkTCPLingerTimeout); err != nil {
-			// We were unable to retrieve a stack config, just use
-			// the DefaultTCPLingerTimeout.
-			if v > tcpip.TCPLingerTimeoutOption(DefaultTCPLingerTimeout) {
-				stkTCPLingerTimeout = tcpip.TCPLingerTimeoutOption(DefaultTCPLingerTimeout)
-			}
-		}
-		// Cap it to the stack wide TCPLinger timeout.
+		// Cap it to MaxTCPLingerTimeout.
+		stkTCPLingerTimeout := tcpip.TCPLingerTimeoutOption(MaxTCPLingerTimeout)
 		if v > stkTCPLingerTimeout {
 			v = stkTCPLingerTimeout
 		}
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index d9abb8d94..2e5093b36 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -62,6 +62,10 @@ const (
 	// FIN_WAIT_2 state before being marked closed.
 	DefaultTCPLingerTimeout = 60 * time.Second
 
+	// MaxTCPLingerTimeout is the maximum amount of time that sockets
+	// linger in FIN_WAIT_2 state before being marked closed.
+	MaxTCPLingerTimeout = 120 * time.Second
+
 	// DefaultTCPTimeWaitTimeout is the amount of time that sockets linger
 	// in TIME_WAIT state before being marked closed.
 	DefaultTCPTimeWaitTimeout = 60 * time.Second
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index fb25b86b9..1b58eb91b 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -6112,7 +6112,7 @@ func TestTCPLingerTimeout(t *testing.T) {
 		{"InRangeLingerTimeout", 10 * time.Second, 10 * time.Second},
 		// Values > stack's TCPLingerTimeout are capped to the stack's
 		// value. Defaults to tcp.DefaultTCPLingerTimeout(60 seconds)
-		{"AboveMaxLingerTimeout", 65 * time.Second, 60 * time.Second},
+		{"AboveMaxLingerTimeout", 125 * time.Second, 120 * time.Second},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {