[PATCH dpdk v5 2/5] net: support multiple stacked VLAN tags

[Robin Jarry]

The VLAN and QinQ code paths in rte_net_get_ptype handle at most two
tags with duplicated logic. Replace them with a single loop that
consumes all consecutive VLAN/QinQ headers regardless of depth.

Bugzilla ID: 1941
Suggested-by: David Marchand <david.marchand at redhat.com>
Signed-off-by: Robin Jarry <rjarry at redhat.com>
---
 lib/net/rte_net.c | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/lib/net/rte_net.c b/lib/net/rte_net.c
index c70b57fdc0f8..d3cded961fb5 100644
--- a/lib/net/rte_net.c
+++ b/lib/net/rte_net.c
@@ -349,29 +349,26 @@ uint32_t rte_net_get_ptype(const struct rte_mbuf *m,
 	if (proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_IPV4))
 		goto l3; /* fast path if packet is IPv4 */
 
-	if (proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_VLAN)) {
+	if ((proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_VLAN)) ||
+		(proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_QINQ))) {
 		const struct rte_vlan_hdr *vh;
 		struct rte_vlan_hdr vh_copy;
 
-		pkt_type = RTE_PTYPE_L2_ETHER_VLAN;
-		vh = rte_pktmbuf_read(m, off, sizeof(*vh), &vh_copy);
-		if (unlikely(vh == NULL))
-			return pkt_type;
-		off += sizeof(*vh);
-		hdr_lens->l2_len += sizeof(*vh);
-		proto = vh->eth_proto;
-	} else if (proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_QINQ)) {
-		const struct rte_vlan_hdr *vh;
-		struct rte_vlan_hdr vh_copy;
+		if (proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_VLAN))
+			pkt_type = RTE_PTYPE_L2_ETHER_VLAN;
+		else
+			pkt_type = RTE_PTYPE_L2_ETHER_QINQ;
+
+		do {
+			vh = rte_pktmbuf_read(m, off, sizeof(*vh), &vh_copy);
+			if (unlikely(vh == NULL))
+				return pkt_type;
+			off += sizeof(*vh);
+			hdr_lens->l2_len += sizeof(*vh);
+			proto = vh->eth_proto;
+		} while (proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_VLAN) ||
+			proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_QINQ));
 
-		pkt_type = RTE_PTYPE_L2_ETHER_QINQ;
-		vh = rte_pktmbuf_read(m, off + sizeof(*vh), sizeof(*vh),
-			&vh_copy);
-		if (unlikely(vh == NULL))
-			return pkt_type;
-		off += 2 * sizeof(*vh);
-		hdr_lens->l2_len += 2 * sizeof(*vh);
-		proto = vh->eth_proto;
 	} else if ((proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_MPLS)) ||
 		(proto == rte_cpu_to_be_16(RTE_ETHER_TYPE_MPLSM))) {
 		unsigned int i;
-- 
2.54.0