netdev - [PATCH net-next-2.6 1/2] jme: Don't show UDP Checksum error if HW misjudged

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Message-Id: <1297661238-1467-1-git-send-email-cooldavid@cooldavid.org>
Date:	Mon, 14 Feb 2011 13:27:17 +0800
From:	"Guo-Fu Tseng" <cooldavid@...ldavid.org>
To:	"David Miller" <davem@...emloft.net>
Cc:	Guo-Fu Tseng <cooldavid@...ldavid.org>,
	"linux-netdev" <netdev@...r.kernel.org>,
	"Aries Lee" <arieslee@...cron.com>,
	"Devinchiu" <devinchiu@...cron.com>,
	"Ethan Hsiao" <ethanhsiao@...cron.com>
Subject: [PATCH net-next-2.6 1/2] jme: Don't show UDP Checksum error if HW misjudged

From: Guo-Fu Tseng <cooldavid@...ldavid.org>

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

Reported-by: Adam Swift <Adam.Swift@...itude.net>
Confirmed-by: "Aries Lee" <arieslee@...cron.com>
Signed-off-by: Guo-Fu Tseng <cooldavid@...ldavid.org>
---
 drivers/net/jme.c |   32 +++++++++++++++++++++++++++++---
 1 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/net/jme.c b/drivers/net/jme.c
index ed35e17..5b441b7 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);
-- 
1.7.2.2

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