diff options
| author | Xie He <xie.he.0141@gmail.com> | 2020-09-02 05:07:06 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-09-02 15:42:43 -0700 |
| commit | 2b7bcd967a0f5b7ac9bb0c37b92de36e073dd119 (patch) | |
| tree | 8fe5274faf22190c932a3f8f5768a825f8aaf1a6 /drivers/net/wan | |
| parent | eb0f3bc463d59d86402f19c59aa44e82dc3fab6d (diff) | |
drivers/net/wan/hdlc: Change the default of hard_header_len to 0
Change the default value of hard_header_len in hdlc.c from 16 to 0.
Currently there are 6 HDLC protocol drivers, among them:
hdlc_raw_eth, hdlc_cisco, hdlc_ppp, hdlc_x25 set hard_header_len when
attaching the protocol, overriding the default. So this patch does not
affect them.
hdlc_raw and hdlc_fr don't set hard_header_len when attaching the
protocol. So this patch will change the hard_header_len of the HDLC
device for them from 16 to 0.
This is the correct change because both hdlc_raw and hdlc_fr don't have
header_ops, and the code in net/packet/af_packet.c expects the value of
hard_header_len to be consistent with header_ops.
In net/packet/af_packet.c, in the packet_snd function,
for AF_PACKET/DGRAM sockets it would reserve a headroom of
hard_header_len and call dev_hard_header to fill in that headroom,
and for AF_PACKET/RAW sockets, it does not reserve the headroom and
does not call dev_hard_header, but checks if the user has provided a
header of length hard_header_len (in function dev_validate_header).
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Martin Schiller <ms@dev.tdt.de>
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')
| -rw-r--r-- | drivers/net/wan/hdlc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c index 386ed2aa31fd..9b00708676cf 100644 --- a/drivers/net/wan/hdlc.c +++ b/drivers/net/wan/hdlc.c @@ -229,7 +229,7 @@ static void hdlc_setup_dev(struct net_device *dev) dev->min_mtu = 68; dev->max_mtu = HDLC_MAX_MTU; dev->type = ARPHRD_RAWHDLC; - dev->hard_header_len = 16; + dev->hard_header_len = 0; dev->needed_headroom = 0; dev->addr_len = 0; dev->header_ops = &hdlc_null_ops; |