Implement /proc/sys/net/ipv4/ip_local_port_range

Speeds up the socket stress tests by a couple orders of magnitude.

PiperOrigin-RevId: 361721050

2 files changed, 20 insertions, 0 deletions

diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go
index f31277d30..6b71bd3a9 100644
--- a/pkg/sentry/inet/inet.go
+++ b/pkg/sentry/inet/inet.go
@@ -93,6 +93,14 @@ type Stack interface {
 
 	// SetForwarding enables or disables packet forwarding between NICs.
 	SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error
+
+	// PortRange returns the UDP and TCP inclusive range of ephemeral ports
+	// used in both IPv4 and IPv6.
+	PortRange() (uint16, uint16)
+
+	// SetPortRange sets the UDP and TCP IPv4 and IPv6 ephemeral port range
+	// (inclusive).
+	SetPortRange(start uint16, end uint16) error
 }
 
 // Interface contains information about a network interface.
diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go
index 9ebeba8a3..03e2608c2 100644
--- a/pkg/sentry/inet/test_stack.go
+++ b/pkg/sentry/inet/test_stack.go
@@ -164,3 +164,15 @@ func (s *TestStack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable b
 	s.IPForwarding = enable
 	return nil
 }
+
+// PortRange implements inet.Stack.PortRange.
+func (*TestStack) PortRange() (uint16, uint16) {
+	// Use the default Linux values per net/ipv4/af_inet.c:inet_init_net().
+	return 32768, 28232
+}
+
+// SetPortRange implements inet.Stack.SetPortRange.
+func (*TestStack) SetPortRange(start uint16, end uint16) error {
+	// No-op.
+	return nil
+}