From 2a6feccc042d710847074c74c2b75de51d055abf Mon Sep 17 00:00:00 2001
From: Hasan Mahmood <hasan.mahmood@datadoghq.com>
Date: Mon, 8 Mar 2021 12:14:18 -0600
Subject: [PATCH] Add route get iif option

---
 route_linux.go | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/route_linux.go b/route_linux.go
index 7e68fe20..a0d70d18 100644
--- a/route_linux.go
+++ b/route_linux.go
@@ -1150,6 +1150,7 @@ func deserializeRoute(m []byte) (Route, error) {
 // RouteGetOptions contains a set of options to use with
 // RouteGetWithOptions
 type RouteGetOptions struct {
+	Iif     string
 	VrfName string
 	SrcAddr net.IP
 }
@@ -1207,6 +1208,21 @@ func (h *Handle) RouteGetWithOptions(destination net.IP, options *RouteGetOption
 			req.AddData(nl.NewRtAttr(unix.RTA_OIF, b))
 		}
 
+		if len(options.Iif) > 0 {
+			link, err := LinkByName(options.Iif)
+			if err != nil {
+				return nil, err
+			}
+
+			var (
+				b      = make([]byte, 4)
+				native = nl.NativeEndian()
+			)
+			native.PutUint32(b, uint32(link.Attrs().Index))
+
+			req.AddData(nl.NewRtAttr(unix.RTA_IIF, b))
+		}
+
 		if options.SrcAddr != nil {
 			var srcAddr []byte
 			if family == FAMILY_V4 {