can: Unify droping of invalid tx skbs and netdev stats

PATCH Superseded Oliver Hartkopp 3 participants 5 messages Jan 11, 2010 – Jan 12, 2010 3 messages not in the archive

Subsystems (4)

Networking Network drivers Arm/Microchip (AT91) SoC support CAN network drivers

lore

Share & tools

lore

Oliver Hartkopp

author

2010-01-11 23:19 UTC #0 lore raw

PATCH v3 1/1 can: Unify droping of invalid tx skbs and netdev stats

As suggested by Marc and Wolfgang here is the v3 version:

To prevent the CAN drivers to operate on invalid socketbuffers the skbs are now checked and silently dropped at the xmit-function consistently.

Also the netdev stats are consistently using the CAN data length code (dlc) for [rx|tx]_bytes now.

Signed-off-by Oliver Hartkopp <[email protected]>

---

drivers/net/can/at91_can.c +3 -0

index 166cc7e..f728749 100644
@@ -342,6 +342,9 @@ static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	unsigned int mb, prio;
 	u32 reg_mid, reg_mcr;
 
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
 	mb = get_tx_next_mb(priv);
 	prio = get_tx_next_prio(priv);

drivers/net/can/bfin_can.c +3 -0

index 0ec1524..7e1926e 100644
@@ -318,6 +318,9 @@ static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	u16 val;
 	int i;
 
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
 	netif_stop_queue(dev);
 
 	/* fill id */

drivers/net/can/mcp251x.c +1 -5

index 9c5a153..d46d084 100644
@@ -494,12 +494,8 @@ static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb,
 		return NETDEV_TX_BUSY;
 	}
 
-	if (skb->len != sizeof(struct can_frame)) {
-		dev_err(&spi->dev, "dropping packet - bad length\n");
-		dev_kfree_skb(skb);
-		net->stats.tx_dropped++;
+	if (can_dropped_invalid_skb(net, skb))
 		return NETDEV_TX_OK;
-	}
 
 	netif_stop_queue(net);
 	priv->tx_skb = skb;

drivers/net/can/sja1000/sja1000.c +3 -0

index 542a4f7..345304d 100644
@@ -249,6 +249,9 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 	uint8_t dreg;
 	int i;
 
+	if (can_dropped_invalid_skb(dev, skb))
+		return NETDEV_TX_OK;
+
 	netif_stop_queue(dev);
 
 	fi = dlc = cf->can_dlc;

drivers/net/can/ti_hecc.c +3 -1

index 5c993c2..7d370e3 100644
@@ -477,6 +477,9 @@ static netdev_tx_t ti_hecc_xmit(struct sk_buff *skb, struct net_device *ndev)
 	u32 mbxno, mbx_mask, data;
 	unsigned long flags;
 
+	if (can_dropped_invalid_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
 	mbxno = get_tx_head_mb(priv);
 	mbx_mask = BIT(mbxno);
 	spin_lock_irqsave(&priv->mbx_lock, flags);

@@ -491,7 +494,6 @@ static netdev_tx_t ti_hecc_xmit(struct sk_buff *skb, struct net_device *ndev)
 	spin_unlock_irqrestore(&priv->mbx_lock, flags);
 
 	/* Prepare mailbox for transmission */
-	data = min_t(u8, cf->can_dlc, 8);
 	if (cf->can_id & CAN_RTR_FLAG) /* Remote transmission request */
 		data |= HECC_CANMCF_RTR;
 	data |= get_tx_head_prio(priv) << 8;

drivers/net/can/usb/ems_usb.c +3 -0

index efbb05c..ddb17e2 100644
@@ -767,6 +767,9 @@ static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *ne
 	size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
 			+ sizeof(struct cpc_can_msg);
 
+	if (can_dropped_invalid_skb(netdev, skb))
+		return NETDEV_TX_OK;
+
 	/* create a URB, and a buffer for it, and copy the data to the URB */
 	urb = usb_alloc_urb(0, GFP_ATOMIC);
 	if (!urb) {

drivers/net/can/vcan.c +11 -3

index 80ac563..66411d5 100644
@@ -70,10 +70,11 @@ MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
 
 static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 {
+	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 
 	stats->rx_packets++;
-	stats->rx_bytes += skb->len;
+	stats->rx_bytes += cf->can_dlc;
 
 	skb->protocol  = htons(ETH_P_CAN);
 	skb->pkt_type  = PACKET_BROADCAST;

@@ -85,11 +86,18 @@ static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 
 static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 {
+	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 	int loop;
 
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		stats->tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
 	stats->tx_packets++;
-	stats->tx_bytes += skb->len;
+	stats->tx_bytes += cf->can_dlc;
 
 	/* set flag whether this packet has to be looped back */
 	loop = skb->pkt_type == PACKET_LOOPBACK;

@@ -103,7 +111,7 @@ static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 			 * CAN core already did the echo for us
 			 */
 			stats->rx_packets++;
-			stats->rx_bytes += skb->len;
+			stats->rx_bytes += cf->can_dlc;
 		}
 		kfree_skb(skb);
 		return NETDEV_TX_OK;

include/linux/can/dev.h +15 -0

index 3db7767..7e7c98a 100644
@@ -60,6 +60,21 @@ struct can_priv {
  */
 #define get_can_dlc(i)	(min_t(__u8, (i), 8))
 
+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+static inline int can_dropped_invalid_skb(struct net_device *dev,
+					  struct sk_buff *skb)
+{
+	const struct can_frame *cf = (struct can_frame *)skb->data;
+
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		dev->stats.tx_dropped++;
+		return 1;
+	}
+
+	return 0;
+}
+
 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
 void free_candev(struct net_device *dev);

A message that is not in the archive (sent off-list or not yet received): [email protected]

David Miller

2010-01-11 23:55 UTC #2 lore raw

From: Oliver Hartkopp <[email protected]>
Date: Tue, 12 Jan 2010 00:19:21 +0100

Quoted 12 lines

static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) {

drivers/net/can/vcan.c +7 -0

+	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 	int loop;
 
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		stats->tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+

...

Quoted 6 lines

include/linux/can/dev.h +6 -0

+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+static inline int can_dropped_invalid_skb(struct net_device *dev,
+					  struct sk_buff *skb)
+{
+	const struct can_frame *cf = (struct can_frame *)skb->data;
+

include/linux/can/dev.h struct can_priv { · line 78

Quoted 10 lines

include/linux/can/dev.h +9 -0

+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		dev->stats.tx_dropped++;
+		return 1;
+	}
+
+	return 0;
+}
+
 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);

Why are you not using the new helper function in vcan_tx()?

A message that is not in the archive (sent off-list or not yet received): 20100111.155537.166350032.davem-fT/PcQaiUtIeIZ0/[email protected]

Oliver Hartkopp

author

2010-01-12 08:32 UTC #4 lore raw

Quoted 26 lines · David Miller

From: Oliver Hartkopp <[email protected]>
Date: Tue, 12 Jan 2010 00:19:21 +0100

Quoted 12 lines

static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) {

drivers/net/can/vcan.c +7 -0

+	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 	int loop;
 
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		stats->tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+

...

Quoted 10 lines

include/linux/can/dev.h +10 -0

+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+static inline int can_dropped_invalid_skb(struct net_device *dev,
+					  struct sk_buff *skb)
+{
+	const struct can_frame *cf = (struct can_frame *)skb->data;
+
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		dev->stats.tx_dropped++;
+		return 1;

Quoted 8 lines

include/linux/can/dev.h struct can_priv { · line 78
Quoted 6 lines
include/linux/can/dev.h +5 -0
+	}
+
+	return 0;
+}
+
 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
Why are you not using the new helper function in vcan_tx()?

I just wanted the vcan driver keep off including "include/linux/can/dev.h" which is intended for 'real' CAN hardware.

As the vcan software devices do not need the bitrate-setting and skb echo handling from the driver library for real CAN devices, this inline function would be the only reason to include ".../dev.h"

But i don't have a strong preference to do it like this. Do you think i should change it to used the defined inline function?

Regards,
Oliver

A message that is not in the archive (sent off-list or not yet received): [email protected]

David Miller

2010-01-12 08:39 UTC #6 lore raw

From: Oliver Hartkopp <[email protected]>
Date: Tue, 12 Jan 2010 09:32:11 +0100

Quoted 2 lines

But i don't have a strong preference to do it like this. Do you think i should change it to used the defined inline function?

Yes, less copies of the same code less bugs.

Wolfgang Grandegger

2010-01-12 08:44 UTC #7 lore raw

In reply to a message not in the archive

Quoted 38 lines · Oliver Hartkopp

Quoted 25 lines · David Miller
From: Oliver Hartkopp <[email protected]>
Date: Tue, 12 Jan 2010 00:19:21 +0100
Quoted 12 lines
static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) {
drivers/net/can/vcan.c +7 -0
+	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 	int loop;
 
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		stats->tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
...
Quoted 9 lines
include/linux/can/dev.h +9 -0
+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+static inline int can_dropped_invalid_skb(struct net_device *dev,
+					  struct sk_buff *skb)
+{
+	const struct can_frame *cf = (struct can_frame *)skb->data;
+
+	if (unlikely(skb->len != sizeof(*cf) || cf->can_dlc > 8)) {
+		kfree_skb(skb);
+		dev->stats.tx_dropped++;
Quoted 8 lines
include/linux/can/dev.h struct can_priv { · line 78
Quoted 7 lines
include/linux/can/dev.h +6 -0
+		return 1;
+	}
+
+	return 0;
+}
+
 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
Why are you not using the new helper function in vcan_tx()?
I just wanted the vcan driver keep off including "include/linux/can/dev.h" which is intended for 'real' CAN hardware.

Quoted 6 lines

As the vcan software devices do not need the bitrate-setting and skb echo handling from the driver library for real CAN devices, this inline function would be the only reason to include ".../dev.h"
But i don't have a strong preference to do it like this. Do you think i should change it to used the defined inline function?

Yes, for the sake of consistency.

Wolfgang.