diff mbox

[net-next,07/12] r8152: support rx checksum

Message ID 1393934464-23675-8-git-send-email-hayeswang@realtek.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Hayes Wang March 4, 2014, noon UTC 
Support hw rx checksum for TCP and UDP packets.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
---
 drivers/net/usb/r8152.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

Comments

David Miller March 4, 2014, 9:32 p.m. UTC | #1 
From: Hayes Wang <hayeswang@realtek.com>
Date: Tue, 4 Mar 2014 20:00:59 +0800

> @@ -1453,11 +1491,19 @@ static void rx_bottom(struct r8152 *tp)
>  			pkt_len -= CRC_SIZE;
>  			rx_data += sizeof(struct rx_desc);
>  
> +			checksum = r8152_rx_csum(tp, rx_desc);
> +			if (checksum == RTL_CHECKSUM_FAIL) {
> +				stats->rx_errors++;
> +				goto find_next_rx;
> +			}
> +

It is not for the driver to make this policy decision and drop the
packet.  It is not a device RX error event.

In fact you do not know what corrupted the checksum, or even if
the device verified it correctly.  Anything is possible.

You must therefore still pass the packet up into the networking
stack using CHECKSUM_NONE, and let the protocols double-check
the checksum(s) in software and bump the appropriate statistic
counter if the checksum is really bad.

This allows allows network taps to see the packet, so that the
administrator can analyze the situation.
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diff mbox

Patch

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index f1eaa18..5fdf0af 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -464,11 +464,23 @@  enum rtl8152_flags {
 #define REALTEK_USB_DEVICE(vend, prod)	\
 	USB_DEVICE_INTERFACE_CLASS(vend, prod, USB_CLASS_VENDOR_SPEC)
 
+#define RTL_CHECKSUM_FAIL		-1
+
 struct rx_desc {
 	__le32 opts1;
+#define RD_CRC				(1 << 15)
 #define RX_LEN_MASK			0x7fff
+
 	__le32 opts2;
+#define RD_UDP_CS			(1 << 23)
+#define RD_TCP_CS			(1 << 22)
+#define RD_IPV4_CS			(1 << 19)
+
 	__le32 opts3;
+#define IPF				(1 << 23) /* IP checksum fail */
+#define UDPF				(1 << 22) /* UDP checksum fail */
+#define TCPF				(1 << 21) /* TCP checksum fail */
+
 	__le32 opts4;
 	__le32 opts5;
 	__le32 opts6;
@@ -1404,6 +1416,31 @@  out_tx_fill:
 	return ret;
 }
 
+static int r8152_rx_csum(struct r8152 *tp, struct rx_desc *rx_desc)
+{
+	int checksum = CHECKSUM_NONE;
+	u32 opts2, opts3;
+
+	if (tp->version == RTL_VER_01)
+		goto return_result;
+
+	opts2 = le32_to_cpu(rx_desc->opts2);
+	opts3 = le32_to_cpu(rx_desc->opts3);
+
+	if (opts2 & RD_IPV4_CS) {
+		if (opts3 & IPF)
+			checksum = RTL_CHECKSUM_FAIL;
+		else if (((opts2 & RD_UDP_CS) && (opts3 & UDPF)) ||
+			 ((opts2 & RD_TCP_CS) && (opts3 & TCPF)))
+			checksum = RTL_CHECKSUM_FAIL;
+		else
+			checksum = CHECKSUM_UNNECESSARY;
+	}
+
+return_result:
+	return checksum;
+}
+
 static void rx_bottom(struct r8152 *tp)
 {
 	unsigned long flags;
@@ -1441,6 +1478,7 @@  static void rx_bottom(struct r8152 *tp)
 			struct net_device_stats *stats = &netdev->stats;
 			unsigned int pkt_len;
 			struct sk_buff *skb;
+			int checksum;
 
 			pkt_len = le32_to_cpu(rx_desc->opts1) & RX_LEN_MASK;
 			if (pkt_len < ETH_ZLEN)
@@ -1453,11 +1491,19 @@  static void rx_bottom(struct r8152 *tp)
 			pkt_len -= CRC_SIZE;
 			rx_data += sizeof(struct rx_desc);
 
+			checksum = r8152_rx_csum(tp, rx_desc);
+			if (checksum == RTL_CHECKSUM_FAIL) {
+				stats->rx_errors++;
+				goto find_next_rx;
+			}
+
 			skb = netdev_alloc_skb_ip_align(netdev, pkt_len);
 			if (!skb) {
 				stats->rx_dropped++;
-				break;
+				goto find_next_rx;
 			}
+
+			skb->ip_summed = checksum;
 			memcpy(skb->data, rx_data, pkt_len);
 			skb_put(skb, pkt_len);
 			skb->protocol = eth_type_trans(skb, netdev);
@@ -1465,6 +1511,7 @@  static void rx_bottom(struct r8152 *tp)
 			stats->rx_packets++;
 			stats->rx_bytes += pkt_len;
 
+find_next_rx:
 			rx_data = rx_agg_align(rx_data + pkt_len + CRC_SIZE);
 			rx_desc = (struct rx_desc *)rx_data;
 			len_used = (int)(rx_data - (u8 *)agg->head);
@@ -3102,8 +3149,8 @@  static int rtl8152_probe(struct usb_interface *intf,
 	netdev->netdev_ops = &rtl8152_netdev_ops;
 	netdev->watchdog_timeo = RTL8152_TX_TIMEOUT;
 
-	netdev->features |= NETIF_F_IP_CSUM;
-	netdev->hw_features = NETIF_F_IP_CSUM;
+	netdev->features |= NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
+	netdev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
 
 	SET_ETHTOOL_OPS(netdev, &ops);