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

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

@@ -0,0 +1,40 @@
+// 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 darwin dragonfly freebsd netbsd openbsd
+
+package ipv4
+
+import (
+	"net"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/net/internal/iana"
+)
+
+func marshalDst(b []byte, cm *ControlMessage) []byte {
+	m := (*syscall.Cmsghdr)(unsafe.Pointer(&b[0]))
+	m.Level = iana.ProtocolIP
+	m.Type = sysIP_RECVDSTADDR
+	m.SetLen(syscall.CmsgLen(net.IPv4len))
+	return b[syscall.CmsgSpace(net.IPv4len):]
+}
+
+func parseDst(cm *ControlMessage, b []byte) {
+	cm.Dst = b[:net.IPv4len]
+}
+
+func marshalInterface(b []byte, cm *ControlMessage) []byte {
+	m := (*syscall.Cmsghdr)(unsafe.Pointer(&b[0]))
+	m.Level = iana.ProtocolIP
+	m.Type = sysIP_RECVIF
+	m.SetLen(syscall.CmsgLen(syscall.SizeofSockaddrDatalink))
+	return b[syscall.CmsgSpace(syscall.SizeofSockaddrDatalink):]
+}
+
+func parseInterface(cm *ControlMessage, b []byte) {
+	sadl := (*syscall.SockaddrDatalink)(unsafe.Pointer(&b[0]))
+	cm.IfIndex = int(sadl.Index)
+}