enable --net-disconnect-ok by default

PiperOrigin-RevId: 686286904

pkg/tcpip/transport/tcp/endpoint_state.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"gvisor.dev/gvisor/pkg/atomicbitops"
+	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
@@ -26,6 +27,15 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
+// logDisconnectOnce ensures we don't spam logs when many connections are terminated.
+var logDisconnectOnce sync.Once
+
+func logDisconnect() {
+	logDisconnectOnce.Do(func() {
+		log.Infof("One or more TCP connections terminated during save")
+	})
+}
+
 // beforeSave is invoked by stateify.
 func (e *Endpoint) beforeSave() {
 	// Stop incoming packets.
@@ -44,6 +54,7 @@ func (e *Endpoint) beforeSave() {
 					Err: fmt.Errorf("endpoint cannot be saved in connected state: local %s:%d, remote %s:%d", e.TransportEndpointInfo.ID.LocalAddress, e.TransportEndpointInfo.ID.LocalPort, e.TransportEndpointInfo.ID.RemoteAddress, e.TransportEndpointInfo.ID.RemotePort),
 				})
 			}
+			logDisconnect()
 			e.resetConnectionLocked(&tcpip.ErrConnectionAborted{})
 			e.mu.Unlock()
 			e.Close()

runsc/config/flags.go

@@ -129,7 +129,7 @@ func RegisterFlags(flagSet *flag.FlagSet) {
 	flagSet.Bool("EXPERIMENTAL-xdp-need-wakeup", true, "EXPERIMENTAL. Use XDP_USE_NEED_WAKEUP with XDP sockets.") // TODO(b/240191988): Figure out whether this helps and remove it as a flag.
 	flagSet.Bool("reproduce-nat", false, "Scrape the host netns NAT table and reproduce it in the sandbox.")
 	flagSet.Bool("reproduce-nftables", false, "Attempt to scrape and reproduce nftable rules inside the sandbox. Overrides reproduce-nat when true.")
-	flagSet.Bool("net-disconnect-ok", false, "Indicates whether open network connections and open unix domain sockets should be disconnected upon save.")
+	flagSet.Bool("net-disconnect-ok", true, "Indicates whether open network connections and open unix domain sockets should be disconnected upon save.")
 
 	// Flags that control sandbox runtime behavior: accelerator related.
 	flagSet.Bool("nvproxy", false, "EXPERIMENTAL: enable support for Nvidia GPUs")