diff options
| author | Xie He <xie.he.0141@gmail.com> | 2020-07-05 17:45:21 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-07-06 12:16:21 -0700 |
| commit | 9dc829a135fb5927f1519de11286e2bbb79f5b66 (patch) | |
| tree | 45c4bd493bec432250eb48c4fb931fdb2d38f212 /drivers/net/wan/lapbether.c | |
| parent | 0f57a1e522f413e87852e632f55de4723e511939 (diff) | |
drivers/net/wan/lapbether: Fixed the value of hard_header_len
When this driver transmits data,
first this driver will remove a pseudo header of 1 byte,
then the lapb module will prepend the LAPB header of 2 or 3 bytes,
then this driver will prepend a length field of 2 bytes,
then the underlying Ethernet device will prepend its own header.
So, the header length required should be:
-1 + 3 + 2 + "the header length needed by the underlying device".
This patch fixes kernel panic when this driver is used with AF_PACKET
SOCK_DGRAM sockets.
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/wan/lapbether.c')
| -rw-r--r-- | drivers/net/wan/lapbether.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c index e30d91a38cfb..284832314f31 100644 --- a/drivers/net/wan/lapbether.c +++ b/drivers/net/wan/lapbether.c @@ -303,7 +303,6 @@ static void lapbeth_setup(struct net_device *dev) dev->netdev_ops = &lapbeth_netdev_ops; dev->needs_free_netdev = true; dev->type = ARPHRD_X25; - dev->hard_header_len = 3; dev->mtu = 1000; dev->addr_len = 0; } @@ -324,6 +323,14 @@ static int lapbeth_new_device(struct net_device *dev) if (!ndev) goto out; + /* When transmitting data: + * first this driver removes a pseudo header of 1 byte, + * then the lapb module prepends an LAPB header of at most 3 bytes, + * then this driver prepends a length field of 2 bytes, + * then the underlying Ethernet device prepends its own header. + */ + ndev->hard_header_len = -1 + 3 + 2 + dev->hard_header_len; + lapbeth = netdev_priv(ndev); lapbeth->axdev = ndev; |