vmxnet3: correctly report gso type for UDP tunnels

JIRA: https://issues.redhat.com/browse/RHEL-96969

commit 982d30c
Author: Ronak Doshi <ronak.doshi@broadcom.com>
Date:   Fri May 30 15:27:00 2025 +0000

    vmxnet3: correctly report gso type for UDP tunnels

    Commit 3d010c8 ("udp: do not accept non-tunnel GSO skbs landing
    in a tunnel") added checks in linux stack to not accept non-tunnel
    GRO packets landing in a tunnel. This exposed an issue in vmxnet3
    which was not correctly reporting GRO packets for tunnel packets.

    This patch fixes this issue by setting correct GSO type for the
    tunnel packets.

    Currently, vmxnet3 does not support reporting inner fields for LRO
    tunnel packets. The issue is not seen for egress drivers that do not
    use skb inner fields. The workaround is to enable tnl-segmentation
    offload on the egress interfaces if the driver supports it. This
    problem pre-exists this patch fix and can be addressed as a separate
    future patch.

    Fixes: dacce2b ("vmxnet3: add geneve and vxlan tunnel offload support")
    Signed-off-by: Ronak Doshi <ronak.doshi@broadcom.com>
    Acked-by: Guolin Yang <guolin.yang@broadcom.com>
    Link: https://patch.msgid.link/20250530152701.70354-1-ronak.doshi@broadcom.com
    [pabeni@redhat.com: dropped the changelog]
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Izabela Bakollari <ibakolla@redhat.com>

Author: Izabela Bakollari

drivers/net/vmxnet3/vmxnet3_drv.c

@@ -1568,6 +1568,30 @@ vmxnet3_get_hdr_len(struct vmxnet3_adapter *adapter, struct sk_buff *skb,
 	return (hlen + (hdr.tcp->doff << 2));
 }
 
+static void
+vmxnet3_lro_tunnel(struct sk_buff *skb, __be16 ip_proto)
+{
+	struct udphdr *uh = NULL;
+
+	if (ip_proto == htons(ETH_P_IP)) {
+		struct iphdr *iph = (struct iphdr *)skb->data;
+
+		if (iph->protocol == IPPROTO_UDP)
+			uh = (struct udphdr *)(iph + 1);
+	} else {
+		struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
+
+		if (iph->nexthdr == IPPROTO_UDP)
+			uh = (struct udphdr *)(iph + 1);
+	}
+	if (uh) {
+		if (uh->check)
+			skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+		else
+			skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
+	}
+}
+
 static int
 vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
 		       struct vmxnet3_adapter *adapter, int quota)
@@ -1881,6 +1905,8 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
 			if (segCnt != 0 && mss != 0) {
 				skb_shinfo(skb)->gso_type = rcd->v4 ?
 					SKB_GSO_TCPV4 : SKB_GSO_TCPV6;
+				if (encap_lro)
+					vmxnet3_lro_tunnel(skb, skb->protocol);
 				skb_shinfo(skb)->gso_size = mss;
 				skb_shinfo(skb)->gso_segs = segCnt;
 			} else if ((segCnt != 0 || skb->len > mtu) && !encap_lro) {