Revert vendor directory to support old golang (GOPATH mode)

gomodule is still in progress to migrate for now, hence multus
team decide to keep vendor directory to support build without
gomodule.

vendor/github.com/vishvananda/netlink/xfrm.go

@@ -0,0 +1,74 @@
+package netlink
+
+import (
+	"fmt"
+	"syscall"
+)
+
+// Proto is an enum representing an ipsec protocol.
+type Proto uint8
+
+const (
+	XFRM_PROTO_ROUTE2    Proto = syscall.IPPROTO_ROUTING
+	XFRM_PROTO_ESP       Proto = syscall.IPPROTO_ESP
+	XFRM_PROTO_AH        Proto = syscall.IPPROTO_AH
+	XFRM_PROTO_HAO       Proto = syscall.IPPROTO_DSTOPTS
+	XFRM_PROTO_COMP      Proto = 0x6c // NOTE not defined on darwin
+	XFRM_PROTO_IPSEC_ANY Proto = syscall.IPPROTO_RAW
+)
+
+func (p Proto) String() string {
+	switch p {
+	case XFRM_PROTO_ROUTE2:
+		return "route2"
+	case XFRM_PROTO_ESP:
+		return "esp"
+	case XFRM_PROTO_AH:
+		return "ah"
+	case XFRM_PROTO_HAO:
+		return "hao"
+	case XFRM_PROTO_COMP:
+		return "comp"
+	case XFRM_PROTO_IPSEC_ANY:
+		return "ipsec-any"
+	}
+	return fmt.Sprintf("%d", p)
+}
+
+// Mode is an enum representing an ipsec transport.
+type Mode uint8
+
+const (
+	XFRM_MODE_TRANSPORT Mode = iota
+	XFRM_MODE_TUNNEL
+	XFRM_MODE_ROUTEOPTIMIZATION
+	XFRM_MODE_IN_TRIGGER
+	XFRM_MODE_BEET
+	XFRM_MODE_MAX
+)
+
+func (m Mode) String() string {
+	switch m {
+	case XFRM_MODE_TRANSPORT:
+		return "transport"
+	case XFRM_MODE_TUNNEL:
+		return "tunnel"
+	case XFRM_MODE_ROUTEOPTIMIZATION:
+		return "ro"
+	case XFRM_MODE_IN_TRIGGER:
+		return "in_trigger"
+	case XFRM_MODE_BEET:
+		return "beet"
+	}
+	return fmt.Sprintf("%d", m)
+}
+
+// XfrmMark represents the mark associated to the state or policy
+type XfrmMark struct {
+	Value uint32
+	Mask  uint32
+}
+
+func (m *XfrmMark) String() string {
+	return fmt.Sprintf("(0x%x,0x%x)", m.Value, m.Mask)
+}