xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

packet: add sockopt to ignore outgoing packets

Browse Source 
Currently, the only way to ignore outgoing packets on a packet socket is
via the BPF filter.  With MSG_ZEROCOPY, packets that are looped into
AF_PACKET are copied in dev_queue_xmit_nit(), and this copy happens even
if the filter run from packet_rcv() would reject them.  So the presence
of a packet socket on the interface takes away the benefits of
MSG_ZEROCOPY, even if the packet socket is not interested in outgoing
packets.  (Even when MSG_ZEROCOPY is not used, the skb is unnecessarily
cloned, but the cost for that is much lower.)

Add a socket option to allow AF_PACKET sockets to ignore outgoing
packets to solve this.  Note that the *BSDs already have something
similar: BIOCSSEESENT/BIOCSDIRECTION and BIOCSDIRFILT.

The first intended user is lldpd.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vincent Whitchurch
2018-09-03 16:23:36 +02:00
committed by David S. Miller
parent 05dcc71298
commit fa788d986a
4 changed files with 22 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
include/uapi/linux/if_packet.h
View File

@@ -57,6 +57,7 @@ struct sockaddr_ll {
#define PACKET_QDISC_BYPASS 20
#define PACKET_ROLLOVER_STATS 21
#define PACKET_FANOUT_DATA 22
#define PACKET_IGNORE_OUTGOING 23
#define PACKET_FANOUT_HASH 0
#define PACKET_FANOUT_LB 1