jme: Don't show UDP Checksum error if HW misjudged

Some JMicron Chip treat 0 as error checksum for UDP packets.
Which should be "No checksum needed".

Reported-by: Adam Swift <Adam.Swift@omnitude.net>
Confirmed-by: "Aries Lee" <arieslee@jmicron.com>
Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 3 deletions

diff --git a/drivers/net/jme.c b/drivers/net/jme.c
index ed35e17f43dc..5b441b75e138 100644
--- a/drivers/net/jme.c
+++ b/drivers/net/jme.c
@@ -956,8 +956,34 @@ jme_disable_rx_engine(struct jme_adapter *jme)
         jme_mac_rxclk_off(jme);
 }
 
+static u16
+jme_udpsum(struct sk_buff *skb)
+{
+        u16 csum = 0xFFFFu;
+
+        if (skb->len < (ETH_HLEN + sizeof(struct iphdr)))
+                return csum;
+        if (skb->protocol != htons(ETH_P_IP))
+                return csum;
+        skb_set_network_header(skb, ETH_HLEN);
+        if ((ip_hdr(skb)->protocol != IPPROTO_UDP) ||
+            (skb->len < (ETH_HLEN +
+                        (ip_hdr(skb)->ihl << 2) +
+                        sizeof(struct udphdr)))) {
+                skb_reset_network_header(skb);
+                return csum;
+        }
+        skb_set_transport_header(skb,
+                        ETH_HLEN + (ip_hdr(skb)->ihl << 2));
+        csum = udp_hdr(skb)->check;
+        skb_reset_transport_header(skb);
+        skb_reset_network_header(skb);
+
+        return csum;
+}
+
 static int
-jme_rxsum_ok(struct jme_adapter *jme, u16 flags)
+jme_rxsum_ok(struct jme_adapter *jme, u16 flags, struct sk_buff *skb)
 {
         if (!(flags & (RXWBFLAG_TCPON | RXWBFLAG_UDPON | RXWBFLAG_IPV4)))
                 return false;
@@ -970,7 +996,7 @@ jme_rxsum_ok(struct jme_adapter *jme, u16 flags)
         }
 
         if (unlikely((flags & (RXWBFLAG_MF | RXWBFLAG_UDPON | RXWBFLAG_UDPCS))
-                        == RXWBFLAG_UDPON)) {
+                        == RXWBFLAG_UDPON) && jme_udpsum(skb)) {
                 if (flags & RXWBFLAG_IPV4)
                         netif_err(jme, rx_err, jme->dev, "UDP Checksum error\n");
                 return false;
@@ -1018,7 +1044,7 @@ jme_alloc_and_feed_skb(struct jme_adapter *jme, int idx)
                 skb_put(skb, framesize);
                 skb->protocol = eth_type_trans(skb, jme->dev);
 
-                if (jme_rxsum_ok(jme, le16_to_cpu(rxdesc->descwb.flags)))
+                if (jme_rxsum_ok(jme, le16_to_cpu(rxdesc->descwb.flags), skb))
                         skb->ip_summed = CHECKSUM_UNNECESSARY;
                 else
                         skb_checksum_none_assert(skb);