netdev-dpdk: Fallback to non tunnel checksum offloading.

The outer checksum offloading API in DPDK is ambiguous and was
implemented by Intel folks in their drivers with the assumption that
any outer offloading always goes with an inner offloading request.

With net/i40e and net/ice drivers, in the case of encapsulating a ARP
packet in a vxlan tunnel (which results in requesting outer ip checksum
with a tunnel context but no inner offloading request), a Tx failure is
triggered, associated with a port MDD event.
2024-03-27T16:02:07.084Z|00018|dpdk|WARN|ice_interrupt_handler(): OICR:
	MDD event

To avoid this situation, if no checksum or segmentation offloading is
requested on the inner part of a packet, fallback to "normal" (non outer)
offloading request.

Reported-at: openvswitch/ovs-issues#321
Fixes: 084c808 ("userspace: Support VXLAN and GENEVE TSO.")
Fixes: f81d782 ("netdev-native-tnl: Mark all vxlan/geneve packets as tunneled.")
Signed-off-by: David Marchand <[email protected]>

lib/netdev-dpdk.c

@@ -2584,16 +2584,18 @@ netdev_dpdk_prep_hwol_packet(struct netdev_dpdk *dev, struct rte_mbuf *mbuf)
     struct dp_packet *pkt = CONTAINER_OF(mbuf, struct dp_packet, mbuf);
     struct tcp_header *th;
 
-    const uint64_t all_requests = (RTE_MBUF_F_TX_IP_CKSUM |
-                                   RTE_MBUF_F_TX_L4_MASK  |
-                                   RTE_MBUF_F_TX_OUTER_IP_CKSUM  |
-                                   RTE_MBUF_F_TX_OUTER_UDP_CKSUM |
-                                   RTE_MBUF_F_TX_TCP_SEG);
-    const uint64_t all_marks = (RTE_MBUF_F_TX_IPV4 |
-                                RTE_MBUF_F_TX_IPV6 |
-                                RTE_MBUF_F_TX_OUTER_IPV4 |
-                                RTE_MBUF_F_TX_OUTER_IPV6 |
-                                RTE_MBUF_F_TX_TUNNEL_MASK);
+    const uint64_t all_inner_requests = (RTE_MBUF_F_TX_IP_CKSUM |
+                                         RTE_MBUF_F_TX_L4_MASK |
+                                         RTE_MBUF_F_TX_TCP_SEG);
+    const uint64_t all_outer_requests = (RTE_MBUF_F_TX_OUTER_IP_CKSUM |
+                                         RTE_MBUF_F_TX_OUTER_UDP_CKSUM);
+    const uint64_t all_requests = all_inner_requests | all_outer_requests;
+    const uint64_t all_inner_marks = (RTE_MBUF_F_TX_IPV4 |
+                                      RTE_MBUF_F_TX_IPV6);
+    const uint64_t all_outer_marks = (RTE_MBUF_F_TX_OUTER_IPV4 |
+                                      RTE_MBUF_F_TX_OUTER_IPV6 |
+                                      RTE_MBUF_F_TX_TUNNEL_MASK);
+    const uint64_t all_marks = all_inner_marks | all_outer_marks;
 
     if (!(mbuf->ol_flags & all_requests)) {
         /* No offloads requested, no marks should be set. */
@@ -2614,34 +2616,43 @@ netdev_dpdk_prep_hwol_packet(struct netdev_dpdk *dev, struct rte_mbuf *mbuf)
      * l2 len and outer l3 len. Inner l2/l3/l4 len are calculated
      * before. */
     const uint64_t tunnel_type = mbuf->ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK;
-    if (tunnel_type == RTE_MBUF_F_TX_TUNNEL_GENEVE ||
-        tunnel_type == RTE_MBUF_F_TX_TUNNEL_VXLAN) {
-        mbuf->outer_l2_len = (char *) dp_packet_l3(pkt) -
-                 (char *) dp_packet_eth(pkt);
-        mbuf->outer_l3_len = (char *) dp_packet_l4(pkt) -
-                 (char *) dp_packet_l3(pkt);
-
-        /* If neither inner checksums nor TSO is requested, inner marks
-         * should not be set. */
-        if (!(mbuf->ol_flags & (RTE_MBUF_F_TX_IP_CKSUM |
-                                RTE_MBUF_F_TX_L4_MASK  |
-                                RTE_MBUF_F_TX_TCP_SEG))) {
-            mbuf->ol_flags &= ~(RTE_MBUF_F_TX_IPV4 |
-                                RTE_MBUF_F_TX_IPV6);
-        }
-    } else if (OVS_UNLIKELY(tunnel_type)) {
+    if (OVS_UNLIKELY(tunnel_type &&
+                     tunnel_type != RTE_MBUF_F_TX_TUNNEL_GENEVE &&
+                     tunnel_type != RTE_MBUF_F_TX_TUNNEL_VXLAN)) {
         VLOG_WARN_RL(&rl, "%s: Unexpected tunnel type: %#"PRIx64,
                      netdev_get_name(&dev->up), tunnel_type);
         netdev_dpdk_mbuf_dump(netdev_get_name(&dev->up),
                               "Packet with unexpected tunnel type", mbuf);
         return false;
+    }
+
+    if (tunnel_type && (mbuf->ol_flags & all_inner_requests)) {
+        mbuf->outer_l2_len = (char *) dp_packet_l3(pkt) -
+                             (char *) dp_packet_eth(pkt);
+        mbuf->outer_l3_len = (char *) dp_packet_l4(pkt) -
+                             (char *) dp_packet_l3(pkt);
     } else {
-        mbuf->l2_len = (char *) dp_packet_l3(pkt) -
-               (char *) dp_packet_eth(pkt);
-        mbuf->l3_len = (char *) dp_packet_l4(pkt) -
-               (char *) dp_packet_l3(pkt);
+        if (tunnel_type) {
+            /* No inner offload is requested, fallback to non tunnel
+             * checksum offloads. */
+            mbuf->ol_flags &= ~all_inner_marks;
+            if (mbuf->ol_flags & RTE_MBUF_F_TX_OUTER_IP_CKSUM) {
+                mbuf->ol_flags |= RTE_MBUF_F_TX_IP_CKSUM;
+                mbuf->ol_flags |= RTE_MBUF_F_TX_IPV4;
+            }
+            if (mbuf->ol_flags & RTE_MBUF_F_TX_OUTER_UDP_CKSUM) {
+                mbuf->ol_flags |= RTE_MBUF_F_TX_UDP_CKSUM;
+                mbuf->ol_flags |= mbuf->ol_flags & RTE_MBUF_F_TX_OUTER_IPV4
+                                  ? RTE_MBUF_F_TX_IPV4 : RTE_MBUF_F_TX_IPV6;
+            }
+            mbuf->ol_flags &= ~(all_outer_requests | all_outer_marks);
+        }
         mbuf->outer_l2_len = 0;
         mbuf->outer_l3_len = 0;
+        mbuf->l2_len = (char *) dp_packet_l3(pkt) -
+                       (char *) dp_packet_eth(pkt);
+        mbuf->l3_len = (char *) dp_packet_l4(pkt) -
+                       (char *) dp_packet_l3(pkt);
     }
     th = dp_packet_l4(pkt);