lib/connections: Support setting traffic class (fixes #3790)

vendor/golang.org/x/net/ipv4/genericopt_stub.go

@@ -0,0 +1,29 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build nacl plan9
+
+package ipv4
+
+// TOS returns the type-of-service field value for outgoing packets.
+func (c *genericOpt) TOS() (int, error) {
+	return 0, errOpNoSupport
+}
+
+// SetTOS sets the type-of-service field value for future outgoing
+// packets.
+func (c *genericOpt) SetTOS(tos int) error {
+	return errOpNoSupport
+}
+
+// TTL returns the time-to-live field value for outgoing packets.
+func (c *genericOpt) TTL() (int, error) {
+	return 0, errOpNoSupport
+}
+
+// SetTTL sets the time-to-live field value for future outgoing
+// packets.
+func (c *genericOpt) SetTTL(ttl int) error {
+	return errOpNoSupport
+}