can: Unify droping of invalid tx skbs and netdev stats

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 <oliver@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 166cc7e..f728749 100644 (file)
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -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);
 

diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
index 0ec1524..7e1926e 100644 (file)
--- a/drivers/net/can/bfin_can.c
+++ b/drivers/net/can/bfin_can.c
@@ -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 */

diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index 1a72ca0..afa2fa4 100644 (file)
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -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;

diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 500d189..40827c1 100644 (file)
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -204,11 +204,8 @@ static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
        int i, rtr, buf_id;
        u32 can_id;
 
-       if (skb->len != sizeof(*frame) || frame->can_dlc > 8) {
-               kfree_skb(skb);
-               dev->stats.tx_dropped++;
+       if (can_dropped_invalid_skb(dev, skb))
                return NETDEV_TX_OK;
-       }
 
        out_8(&regs->cantier, 0);
 

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 542a4f7..345304d 100644 (file)
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -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;

diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 5c993c2..7d370e3 100644 (file)
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -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;

diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index efbb05c..ddb17e2 100644 (file)
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -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) {

diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
index 80ac563..d124d83 100644 (file)
--- a/drivers/net/can/vcan.c
+++ b/drivers/net/can/vcan.c
@@ -47,6 +47,7 @@
 #include <linux/if_arp.h>
 #include <linux/if_ether.h>
 #include <linux/can.h>
+#include <linux/can/dev.h>
 #include <net/rtnetlink.h>
 
 static __initdata const char banner[] =
@@ -70,10 +71,11 @@ 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 +87,15 @@ 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 (can_dropped_invalid_skb(dev, skb))
+               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 +109,7 @@ 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;

diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 3db7767..7e7c98a 100644 (file)
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -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);