tools: psock_tpacket: block Rx until socket filter has been added and socket has...
authorSowmini Varadhan <sowmini.varadhan@oracle.com>
Thu, 5 Jan 2017 19:06:22 +0000 (11:06 -0800)
committerDavid S. Miller <davem@davemloft.net>
Thu, 5 Jan 2017 20:03:41 +0000 (15:03 -0500)
commitc1878f7a89efbbe1ac0082d09b2928782a6ceba1
tree04dab5c2650cddd666620ca3972d8e8b9634e78e
parentad02c4f547826167a709dab8a89a1caefd2c1f50
tools: psock_tpacket: block Rx until socket filter has been added and socket has been bound to loopback.

Packets from any/all interfaces may be queued up on the PF_PACKET socket
before it is bound to the loopback interface by psock_tpacket, and
when these are passed up by the kernel, they could interfere
with the Rx tests.

Avoid interference from spurious packet by blocking Rx until the
socket filter has been set up, and the packet has been bound to the
desired (lo) interface. The effective sequence is
socket(PF_PACKET, SOCK_RAW, 0);
set up ring
Invoke SO_ATTACH_FILTER
bind to sll_protocol set to ETH_P_ALL, sll_ifindex for lo
After this sequence, the only packets that will be passed up are
those received on loopback that pass the attached filter.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tools/testing/selftests/net/psock_tpacket.c