The csum FWD mode parses any received packet to set mbuf offloads for the
transmitting burst, mainly in the checksum/TSO areas.
In the case of a tunnel header, the csum FWD tries to detect known tunnels
by the standard definition using the header'sdata and fallback to check the
packet type in the mbuf to see if the Rx port driver already sign the
packet as a tunnel.
In the fallback case, the csum assumes the tunnel is VXLAN and parses the
tunnel as VXLAN.
When the GENEVE tunnel was added to the known tunnels in csum, its parsing
trial was wrongly located after the pkt type detection, causing the csum to
parse the GENEVE header as VXLAN when the Rx port set the tunnel packet
type.

Remove the fall back case to VxLan.
Log error of unrecognized tunnel if no tunnel was parsed successfully.

Fixes: ea0e711b8ae0 ("app/testpmd: add GENEVE parsing")
Cc: stable@dpdk.org

Signed-off-by: Raja Zidane <rzidane@nvidia.com>
---
V2: Log error when an unrecognized tunnel is found (unknown UDP dst port), instead of parsing it as VxLan by default.

 app/test-pmd/csumonly.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
index 02bc3929c7..210f4263f8 100644
--- a/app/test-pmd/csumonly.c
+++ b/app/test-pmd/csumonly.c
@@ -255,11 +255,10 @@ parse_gtp(struct rte_udp_hdr *udp_hdr,
 	info->l2_len += RTE_ETHER_GTP_HLEN;
 }
 
-/* Parse a vxlan header */
+/* Parse a vxlan header. */
 static void
 parse_vxlan(struct rte_udp_hdr *udp_hdr,
-	    struct testpmd_offload_info *info,
-	    uint32_t pkt_type)
+	    struct testpmd_offload_info *info)
 {
 	struct rte_ether_hdr *eth_hdr;
 
@@ -267,8 +266,7 @@ parse_vxlan(struct rte_udp_hdr *udp_hdr,
 	 * default vxlan port (rfc7348) or that the rx offload flag is set
 	 * (i40e only currently)
 	 */
-	if (udp_hdr->dst_port != _htons(RTE_VXLAN_DEFAULT_PORT) &&
-		RTE_ETH_IS_TUNNEL_PKT(pkt_type) == 0)
+	if (udp_hdr->dst_port != _htons(RTE_VXLAN_DEFAULT_PORT))
 		return;
 
 	update_tunnel_outer(info);
@@ -922,19 +920,24 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 						RTE_MBUF_F_TX_TUNNEL_VXLAN_GPE;
 					goto tunnel_update;
 				}
-				parse_vxlan(udp_hdr, &info,
-					    m->packet_type);
+				parse_geneve(udp_hdr, &info);
 				if (info.is_tunnel) {
 					tx_ol_flags |=
-						RTE_MBUF_F_TX_TUNNEL_VXLAN;
+						RTE_MBUF_F_TX_TUNNEL_GENEVE;
 					goto tunnel_update;
 				}
-				parse_geneve(udp_hdr, &info);
+				parse_vxlan(udp_hdr, &info);
 				if (info.is_tunnel) {
 					tx_ol_flags |=
-						RTE_MBUF_F_TX_TUNNEL_GENEVE;
+						RTE_MBUF_F_TX_TUNNEL_VXLAN;

After adding default case, i suppose swapping of parse_vxlan & parse_geneve is not needed.
Can we revert these above changes.

 					goto tunnel_update;
 				}
+				/* Always keep last. */
+				if (unlikely(RTE_ETH_IS_TUNNEL_PKT(
+							m->packet_type) != 0)) {
+					TESTPMD_LOG(ERR, "Unknown tunnel packet. UDP dst port: %hu",
+						udp_hdr->dst_port);
+				}
 			} else if (info.l4_proto == IPPROTO_GRE) {
 				struct simple_gre_hdr *gre_hdr;