[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.march...@redhat.com>
Signed-off-by: Robin Jarry <rja...@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