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| author | Oliver Hartkopp <oliver@hartkopp.net> | 2009-12-12 05:13:21 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-12-14 04:47:42 +0100 |
| commit | c7cd606f60e7679c7f9eee7010f02a6f000209c1 (patch) | |
| tree | 31c19fd7617ede807757b0ae5c29d218587dc43f /drivers/net/can/sja1000 | |
| parent | net: Fix userspace RTM_NEWLINK notifications. (diff) | |
| download | linux-c7cd606f60e7679c7f9eee7010f02a6f000209c1.tar.xz linux-c7cd606f60e7679c7f9eee7010f02a6f000209c1.zip | |
can: Fix data length code handling in rx path
A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes.
When reading the CAN controllers register the 4-bit value may contain values
from 0 .. 15 which may exceed the reserved space in the socket buffer!
The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8
should be reduced to 8 without any error reporting or frame drop.
This patch introduces a new helper macro to cast a given 4-bit data length
code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes.
The different handlings in the rx path of the CAN netdevice drivers are fixed.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/can/sja1000')
| -rw-r--r-- | drivers/net/can/sja1000/sja1000.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c index b4ba88a31075..542a4f7255b4 100644 --- a/drivers/net/can/sja1000/sja1000.c +++ b/drivers/net/can/sja1000/sja1000.c @@ -293,15 +293,14 @@ static void sja1000_rx(struct net_device *dev) uint8_t fi; uint8_t dreg; canid_t id; - uint8_t dlc; int i; + /* create zero'ed CAN frame buffer */ skb = alloc_can_skb(dev, &cf); if (skb == NULL) return; fi = priv->read_reg(priv, REG_FI); - dlc = fi & 0x0F; if (fi & FI_FF) { /* extended frame format (EFF) */ @@ -318,16 +317,15 @@ static void sja1000_rx(struct net_device *dev) | (priv->read_reg(priv, REG_ID2) >> 5); } - if (fi & FI_RTR) + if (fi & FI_RTR) { id |= CAN_RTR_FLAG; + } else { + cf->can_dlc = get_can_dlc(fi & 0x0F); + for (i = 0; i < cf->can_dlc; i++) + cf->data[i] = priv->read_reg(priv, dreg++); + } cf->can_id = id; - cf->can_dlc = dlc; - for (i = 0; i < dlc; i++) - cf->data[i] = priv->read_reg(priv, dreg++); - - while (i < 8) - cf->data[i++] = 0; /* release receive buffer */ priv->write_reg(priv, REG_CMR, CMD_RRB); @@ -335,7 +333,7 @@ static void sja1000_rx(struct net_device *dev) netif_rx(skb); stats->rx_packets++; - stats->rx_bytes += dlc; + stats->rx_bytes += cf->can_dlc; } static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status) |