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authorXie He <xie.he.0141@gmail.com>2020-09-02 15:07:06 +0300
committerDavid S. Miller <davem@davemloft.net>2020-09-03 01:42:43 +0300
commit2b7bcd967a0f5b7ac9bb0c37b92de36e073dd119 (patch)
tree8fe5274faf22190c932a3f8f5768a825f8aaf1a6 /drivers/net/wan
parenteb0f3bc463d59d86402f19c59aa44e82dc3fab6d (diff)
downloadlinux-2b7bcd967a0f5b7ac9bb0c37b92de36e073dd119.tar.xz
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.c2
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;