can: provide library functions for skb allocation

This patch makes the private functions alloc_can_skb() and
alloc_can_err_skb() of the at91_can driver public and adapts all
drivers to use these. While making the patch I realized, that
the skb's are *not* setup consistently. It's now done as shown
below:

  skb->protocol = htons(ETH_P_CAN);
  skb->pkt_type = PACKET_BROADCAST;
  skb->ip_summed = CHECKSUM_UNNECESSARY;
  *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
  memset(*cf, 0, sizeof(struct can_frame));

The frame is zeroed out to avoid uninitialized data to be passed to
user space. Some drivers or library code did not set "pkt_type" or
"ip_summed". Also,  "__constant_htons()" should not be used for
runtime invocations, as pointed out by David Miller.

Signed-off-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 b13fd91..cbe3fce 100644 (file)
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -221,38 +221,6 @@ static inline void set_mb_mode(const struct at91_priv *priv, unsigned int mb,
        set_mb_mode_prio(priv, mb, mode, 0);
 }
 
-static struct sk_buff *alloc_can_skb(struct net_device *dev,
-               struct can_frame **cf)
-{
-       struct sk_buff *skb;
-
-       skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
-       if (unlikely(!skb))
-               return NULL;
-
-       skb->protocol = htons(ETH_P_CAN);
-       skb->ip_summed = CHECKSUM_UNNECESSARY;
-       *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-
-       return skb;
-}
-
-static struct sk_buff *alloc_can_err_skb(struct net_device *dev,
-               struct can_frame **cf)
-{
-       struct sk_buff *skb;
-
-       skb = alloc_can_skb(dev, cf);
-       if (unlikely(!skb))
-               return NULL;
-
-       memset(*cf, 0, sizeof(struct can_frame));
-       (*cf)->can_id = CAN_ERR_FLAG;
-       (*cf)->can_dlc = CAN_ERR_DLC;
-
-       return skb;
-}
-
 /*
  * Swtich transceiver on or off
  */

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 39b99f5..c3db111 100644 (file)
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -366,17 +366,12 @@ void can_restart(unsigned long data)
        can_flush_echo_skb(dev);
 
        /* send restart message upstream */
-       skb = dev_alloc_skb(sizeof(struct can_frame));
+       skb = alloc_can_err_skb(dev, &cf);
        if (skb == NULL) {
                err = -ENOMEM;
                goto restart;
        }
-       skb->dev = dev;
-       skb->protocol = htons(ETH_P_CAN);
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-       memset(cf, 0, sizeof(struct can_frame));
-       cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
-       cf->can_dlc = CAN_ERR_DLC;
+       cf->can_id |= CAN_ERR_RESTARTED;
 
        netif_rx(skb);
 
@@ -449,6 +444,39 @@ static void can_setup(struct net_device *dev)
        dev->features = NETIF_F_NO_CSUM;
 }
 
+struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
+{
+       struct sk_buff *skb;
+
+       skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
+       if (unlikely(!skb))
+               return NULL;
+
+       skb->protocol = htons(ETH_P_CAN);
+       skb->pkt_type = PACKET_BROADCAST;
+       skb->ip_summed = CHECKSUM_UNNECESSARY;
+       *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
+       memset(*cf, 0, sizeof(struct can_frame));
+
+       return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_can_skb);
+
+struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
+{
+       struct sk_buff *skb;
+
+       skb = alloc_can_skb(dev, cf);
+       if (unlikely(!skb))
+               return NULL;
+
+       (*cf)->can_id = CAN_ERR_FLAG;
+       (*cf)->can_dlc = CAN_ERR_DLC;
+
+       return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_can_err_skb);
+
 /*
  * Allocate and setup space for the CAN network device
  */

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 96d8be4..1a9c595 100644 (file)
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -296,11 +296,9 @@ static void sja1000_rx(struct net_device *dev)
        uint8_t dlc;
        int i;
 
-       skb = dev_alloc_skb(sizeof(struct can_frame));
+       skb = alloc_can_skb(dev, &cf);
        if (skb == NULL)
                return;
-       skb->dev = dev;
-       skb->protocol = htons(ETH_P_CAN);
 
        fi = priv->read_reg(priv, REG_FI);
        dlc = fi & 0x0F;
@@ -351,15 +349,9 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
        enum can_state state = priv->can.state;
        uint8_t ecc, alc;
 
-       skb = dev_alloc_skb(sizeof(struct can_frame));
+       skb = alloc_can_err_skb(dev, &cf);
        if (skb == NULL)
                return -ENOMEM;
-       skb->dev = dev;
-       skb->protocol = htons(ETH_P_CAN);
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-       memset(cf, 0, sizeof(struct can_frame));
-       cf->can_id = CAN_ERR_FLAG;
-       cf->can_dlc = CAN_ERR_DLC;
 
        if (isrc & IRQ_DOI) {
                /* data overrun interrupt */

diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 23a7128..07e8016 100644 (file)
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -535,18 +535,15 @@ static int ti_hecc_rx_pkt(struct ti_hecc_priv *priv, int mbxno)
        u32 data, mbx_mask;
        unsigned long flags;
 
-       skb = netdev_alloc_skb(priv->ndev, sizeof(struct can_frame));
+       skb = alloc_can_skb(priv->ndev, &cf);
        if (!skb) {
                if (printk_ratelimit())
                        dev_err(priv->ndev->dev.parent,
-                               "ti_hecc_rx_pkt: netdev_alloc_skb() failed\n");
+                               "ti_hecc_rx_pkt: alloc_can_skb() failed\n");
                return -ENOMEM;
        }
-       skb->protocol = __constant_htons(ETH_P_CAN);
-       skb->ip_summed = CHECKSUM_UNNECESSARY;
 
        mbx_mask = BIT(mbxno);
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
        data = hecc_read_mbx(priv, mbxno, HECC_CANMID);
        if (data & HECC_CANMID_IDE)
                cf->can_id = (data & CAN_EFF_MASK) | CAN_EFF_FLAG;
@@ -656,19 +653,13 @@ static int ti_hecc_error(struct net_device *ndev, int int_status,
        struct sk_buff *skb;
 
        /* propogate the error condition to the can stack */
-       skb = netdev_alloc_skb(ndev, sizeof(struct can_frame));
+       skb = alloc_can_err_skb(ndev, &cf);
        if (!skb) {
                if (printk_ratelimit())
                        dev_err(priv->ndev->dev.parent,
-                               "ti_hecc_error: netdev_alloc_skb() failed\n");
+                               "ti_hecc_error: alloc_can_err_skb() failed\n");
                return -ENOMEM;
        }
-       skb->protocol = __constant_htons(ETH_P_CAN);
-       skb->ip_summed = CHECKSUM_UNNECESSARY;
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-       memset(cf, 0, sizeof(struct can_frame));
-       cf->can_id = CAN_ERR_FLAG;
-       cf->can_dlc = CAN_ERR_DLC;
 
        if (int_status & HECC_CANGIF_WLIF) { /* warning level int */
                if ((int_status & HECC_CANGIF_BOIF) == 0) {

diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index a65f56a..3685f3e 100644 (file)
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -311,14 +311,10 @@ static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
        int i;
        struct net_device_stats *stats = &dev->netdev->stats;
 
-       skb = netdev_alloc_skb(dev->netdev, sizeof(struct can_frame));
+       skb = alloc_can_skb(dev->netdev, &cf);
        if (skb == NULL)
                return;
 
-       skb->protocol = htons(ETH_P_CAN);
-
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-
        cf->can_id = msg->msg.can_msg.id;
        cf->can_dlc = min_t(u8, msg->msg.can_msg.length, 8);
 
@@ -346,18 +342,10 @@ static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
        struct sk_buff *skb;
        struct net_device_stats *stats = &dev->netdev->stats;
 
-       skb = netdev_alloc_skb(dev->netdev, sizeof(struct can_frame));
+       skb = alloc_can_err_skb(dev->netdev, &cf);
        if (skb == NULL)
                return;
 
-       skb->protocol = htons(ETH_P_CAN);
-
-       cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
-       memset(cf, 0, sizeof(struct can_frame));
-
-       cf->can_id = CAN_ERR_FLAG;
-       cf->can_dlc = CAN_ERR_DLC;
-
        if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
                u8 state = msg->msg.can_state;
 

diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 1d3f7f0..1ed2a5c 100644 (file)
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -68,4 +68,8 @@ void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 void can_get_echo_skb(struct net_device *dev, unsigned int idx);
 void can_free_echo_skb(struct net_device *dev, unsigned int idx);
 
+struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
+struct sk_buff *alloc_can_err_skb(struct net_device *dev,
+                                 struct can_frame **cf);
+
 #endif /* CAN_DEV_H */