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e1000e: don't generate bad checksums for tcp packets with 0 csum

PATCH Applied Jeff Kirsher 2 participants 4 messages Oct 9, 2008

Subsystems (2)
Networking Network drivers
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Jeff Kirsher

author
#0 lore raw

PATCH 1/2 e1000e: don't generate bad checksums for tcp packets with 0 csum

From: Dave Graham <[email protected]>

When offloading transmit checksums only, the driver was not correctly configuring the hardware to handle the case of a zero checksum. For UDP the correct behavior is to leave it alone, but for tcp the checksum must be changed from 0x0000 to 0xFFFF. The hardware takes care of this case but only if it is told the packet is tcp.

Signed-off-by Dave Graham <[email protected]>
Signed-off-by Jesse Brandeburg <[email protected]>
Signed-off-by Jeff Kirsher <[email protected]>

---

 drivers/net/e1000e/netdev.c |   62 +++++++++++++++++++++++++++----------------
 1 files changed, 39 insertions(+), 23 deletions(-)
drivers/net/e1000e/netdev.c +39 -23
index 1b72749..abd492b 100644
@@ -3749,34 +3749,50 @@ static bool e1000_tx_csum(struct e1000_adapter *adapter, struct sk_buff *skb)
 	struct e1000_buffer *buffer_info;
 	unsigned int i;
 	u8 css;
+	u32 cmd_len = E1000_TXD_CMD_DEXT;
 
-	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		css = skb_transport_offset(skb);
-
-		i = tx_ring->next_to_use;
-		buffer_info = &tx_ring->buffer_info[i];
-		context_desc = E1000_CONTEXT_DESC(*tx_ring, i);
-
-		context_desc->lower_setup.ip_config = 0;
-		context_desc->upper_setup.tcp_fields.tucss = css;
-		context_desc->upper_setup.tcp_fields.tucso =
-					css + skb->csum_offset;
-		context_desc->upper_setup.tcp_fields.tucse = 0;
-		context_desc->tcp_seg_setup.data = 0;
-		context_desc->cmd_and_length = cpu_to_le32(E1000_TXD_CMD_DEXT);
+	if (skb->ip_summed != CHECKSUM_PARTIAL)
+		return 0;
 
-		buffer_info->time_stamp = jiffies;
-		buffer_info->next_to_watch = i;
+	switch (skb->protocol) {
+	case __constant_htons(ETH_P_IP):
+		if (ip_hdr(skb)->protocol == IPPROTO_TCP)
+			cmd_len |= E1000_TXD_CMD_TCP;
+		break;
+	case __constant_htons(ETH_P_IPV6):
+		/* XXX not handling all IPV6 headers */
+		if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
+			cmd_len |= E1000_TXD_CMD_TCP;
+		break;
+	default:
+		if (unlikely(net_ratelimit()))
+			e_warn("checksum_partial proto=%x!\n", skb->protocol);
+		break;
+	}
 
-		i++;
-		if (i == tx_ring->count)
-			i = 0;
-		tx_ring->next_to_use = i;
+	css = skb_transport_offset(skb);
 
-		return 1;
-	}
+	i = tx_ring->next_to_use;
+	buffer_info = &tx_ring->buffer_info[i];
+	context_desc = E1000_CONTEXT_DESC(*tx_ring, i);
+
+	context_desc->lower_setup.ip_config = 0;
+	context_desc->upper_setup.tcp_fields.tucss = css;
+	context_desc->upper_setup.tcp_fields.tucso =
+				css + skb->csum_offset;
+	context_desc->upper_setup.tcp_fields.tucse = 0;
+	context_desc->tcp_seg_setup.data = 0;
+	context_desc->cmd_and_length = cpu_to_le32(cmd_len);
+
+	buffer_info->time_stamp = jiffies;
+	buffer_info->next_to_watch = i;
+
+	i++;
+	if (i == tx_ring->count)
+		i = 0;
+	tx_ring->next_to_use = i;
 
-	return 0;
+	return 1;
 }
 
 #define E1000_MAX_PER_TXD	8192
author
#1 lore raw

PATCH 2/2 e1000: don't generate bad checksums for tcp packets with 0 csum

From: Dave Graham <[email protected]>

When offloading transmit checksums only, the driver was not correctly configuring the hardware to handle the case of a zero checksum. For UDP the correct behavior is to leave it alone, but for tcp the checksum must be changed from 0x0000 to 0xFFFF. The hardware takes care of this case but only if it is told the packet is tcp.

same patch as e1000e

Signed-off-by Dave Graham <[email protected]>
Signed-off-by Jesse Brandeburg <[email protected]>
Signed-off-by Jeff Kirsher <[email protected]>

---

 drivers/net/e1000/e1000_main.c |   55 ++++++++++++++++++++++++++--------------
 1 files changed, 36 insertions(+), 19 deletions(-)
drivers/net/e1000/e1000_main.c +36 -19
index 2ab44db..3bafaed 100644
@@ -2873,32 +2873,49 @@ static bool e1000_tx_csum(struct e1000_adapter *adapter,
 	struct e1000_buffer *buffer_info;
 	unsigned int i;
 	u8 css;
+	u32 cmd_len = E1000_TXD_CMD_DEXT;
 
-	if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
-		css = skb_transport_offset(skb);
+	if (skb->ip_summed != CHECKSUM_PARTIAL)
+		return false;
 
-		i = tx_ring->next_to_use;
-		buffer_info = &tx_ring->buffer_info[i];
-		context_desc = E1000_CONTEXT_DESC(*tx_ring, i);
+	switch (skb->protocol) {
+	case __constant_htons(ETH_P_IP):
+		if (ip_hdr(skb)->protocol == IPPROTO_TCP)
+			cmd_len |= E1000_TXD_CMD_TCP;
+		break;
+	case __constant_htons(ETH_P_IPV6):
+		/* XXX not handling all IPV6 headers */
+		if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
+			cmd_len |= E1000_TXD_CMD_TCP;
+		break;
+	default:
+		if (unlikely(net_ratelimit()))
+			DPRINTK(DRV, WARNING,
+			        "checksum_partial proto=%x!\n", skb->protocol);
+		break;
+	}
 
-		context_desc->lower_setup.ip_config = 0;
-		context_desc->upper_setup.tcp_fields.tucss = css;
-		context_desc->upper_setup.tcp_fields.tucso =
-			css + skb->csum_offset;
-		context_desc->upper_setup.tcp_fields.tucse = 0;
-		context_desc->tcp_seg_setup.data = 0;
-		context_desc->cmd_and_length = cpu_to_le32(E1000_TXD_CMD_DEXT);
+	css = skb_transport_offset(skb);
 
-		buffer_info->time_stamp = jiffies;
-		buffer_info->next_to_watch = i;
+	i = tx_ring->next_to_use;
+	buffer_info = &tx_ring->buffer_info[i];
+	context_desc = E1000_CONTEXT_DESC(*tx_ring, i);
 
-		if (unlikely(++i == tx_ring->count)) i = 0;
-		tx_ring->next_to_use = i;
+	context_desc->lower_setup.ip_config = 0;
+	context_desc->upper_setup.tcp_fields.tucss = css;
+	context_desc->upper_setup.tcp_fields.tucso =
+		css + skb->csum_offset;
+	context_desc->upper_setup.tcp_fields.tucse = 0;
+	context_desc->tcp_seg_setup.data = 0;
+	context_desc->cmd_and_length = cpu_to_le32(cmd_len);
 
-		return true;
-	}
+	buffer_info->time_stamp = jiffies;
+	buffer_info->next_to_watch = i;
 
-	return false;
+	if (unlikely(++i == tx_ring->count)) i = 0;
+	tx_ring->next_to_use = i;
+
+	return true;
 }
 
 #define E1000_MAX_TXD_PWR	12
maintainer Applied
#3 lore raw
In reply to Jeff Kirsher

From: Jeff Kirsher <[email protected]>
Date: Thu, 09 Oct 2008 09:58:31 -0700

Quoted 10 lines

When offloading transmit checksums only, the driver was not correctly configuring the hardware to handle the case of a zero checksum. For UDP the correct behavior is to leave it alone, but for tcp the checksum must be changed from 0x0000 to 0xFFFF. The hardware takes care of this case but only if it is told the packet is tcp.

Signed-off-by Dave Graham <[email protected]>
Signed-off-by Jesse Brandeburg <[email protected]>
Signed-off-by Jeff Kirsher <[email protected]>

Applied.

maintainer Applied
#2 lore raw

Re: [NET-NEXT PATCH 2/2] e1000: don't generate bad checksums for tcp packets with 0 csum

In reply to Jeff Kirsher

From: Jeff Kirsher <[email protected]>
Date: Thu, 09 Oct 2008 09:58:52 -0700

Quoted 7 lines

When offloading transmit checksums only, the driver was not correctly configuring the hardware to handle the case of a zero checksum. For UDP the correct behavior is to leave it alone, but for tcp the checksum must be changed from 0x0000 to 0xFFFF. The hardware takes care of this case but only if it is told the packet is tcp.

Quoted 5 lines

same patch as e1000e

Signed-off-by Dave Graham <[email protected]>
Signed-off-by Jesse Brandeburg <[email protected]>
Signed-off-by Jeff Kirsher <[email protected]>

Applied.