Add UDP matchers.

1 files changed, 5 insertions, 5 deletions

diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index 85512f9b2..6597e6781 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -353,6 +353,11 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
 	}
 	pkt.NetworkHeader = headerView[:h.HeaderLength()]
 
+	hlen := int(h.HeaderLength())
+	tlen := int(h.TotalLength())
+	pkt.Data.TrimFront(hlen)
+	pkt.Data.CapLength(tlen - hlen)
+
 	// iptables filtering. All packets that reach here are intended for
 	// this machine and will not be forwarded.
 	ipt := e.stack.IPTables()
@@ -361,11 +366,6 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt tcpip.PacketBuffer) {
 		return
 	}
 
-	hlen := int(h.HeaderLength())
-	tlen := int(h.TotalLength())
-	pkt.Data.TrimFront(hlen)
-	pkt.Data.CapLength(tlen - hlen)
-
 	more := (h.Flags() & header.IPv4FlagMoreFragments) != 0
 	if more || h.FragmentOffset() != 0 {
 		if pkt.Data.Size() == 0 {