[RFC,3/3] selftests: net: veth: add tests for set_channel

diff --git a/tools/testing/selftests/net/veth.sh b/tools/testing/selftests/net/veth.sh
index 11d7cdb898c0..1f4cdbe6ffe0 100755
--- a/tools/testing/selftests/net/veth.sh
+++ b/tools/testing/selftests/net/veth.sh
@@ -75,6 +75,31 @@  chk_tso_flag() {
 	__chk_flag "$1" $2 $3 tcp-segmentation-offload
 }
 
+chk_channels() {
+	local msg="$1"
+	local target=$2
+	local rx=$3
+	local tx=$4
+
+	local dev=veth$target
+	local combined=$tx
+	[ $rx -lt $tx ] && combined=$rx
+
+	local cur_rx=`ip netns exec $BASE$target ethtool -l $dev |\
+		grep RX: | tail -n 1 | awk '{print $2}' `
+	local cur_tx=`ip netns exec $BASE$target ethtool -l $dev |\
+		grep TX: | tail -n 1 | awk '{print $2}'`
+	local cur_combined=`ip netns exec $BASE$target ethtool -l $dev |\
+		grep Combined: | tail -n 1 | awk '{print $2}'`
+
+	printf "%-60s" "$msg"
+	if [ "$cur_rx" = "$rx" -a "$cur_tx" = "$tx" -a "$cur_combined" = "$combined" ]; then
+		echo " ok "
+	else
+		echo " fail rx:$rx:$cur_rx tx:$tx:$cur_tx combined:$combined:$cur_combined"
+	fi
+}
+
 chk_gro() {
 	local msg="$1"
 	local expected=$2
@@ -122,6 +147,8 @@  ip netns exec $NS_SRC ethtool -K veth$SRC tx-udp-segmentation off
 chk_gro "        - aggregation with TSO off" 10
 cleanup
 
+# reset default, just in case
+echo 1 > /sys/module/veth/parameters/tx_queues
 create_ns
 ip netns exec $NS_DST ethtool -K veth$DST gro on
 chk_gro_flag "with gro on - gro flag" $DST on
@@ -134,6 +161,11 @@  chk_gro "        - aggregation with TSO off" 1
 cleanup
 
 create_ns
+chk_channels "default channels" $DST 1 1
+
+# will affect next veth device pair creation
+echo 128 > /sys/module/veth/parameters/tx_queues
+
 ip -n $NS_DST link set dev veth$DST down
 ip netns exec $NS_DST ethtool -K veth$DST gro on
 chk_gro_flag "with gro enabled on link down - gro flag" $DST on
@@ -147,7 +179,35 @@  chk_gro "        - aggregation with TSO off" 1
 cleanup
 
 create_ns
+
+ip netns exec $NS_DST ethtool -L veth$DST tx 2
+chk_channels "setting tx channels" $DST 128 2
+
+ip netns exec $NS_DST ethtool -L veth$DST rx 3 tx 4
+chk_channels "setting both rx and tx channels" $DST 3 4
+ip netns exec $NS_DST ethtool -L veth$DST combined 2 2>/dev/null
+chk_channels "bad setting: combined channels" $DST 3 4
+
+ip netns exec $NS_DST ethtool -L veth$DST tx 1025 2>/dev/null
+chk_channels "setting invalid channels nr" $DST 3 4
+
+printf "%-60s" "bad setting: XDP with RX nr less than TX"
+ip -n $NS_DST link set dev veth$DST xdp object ../bpf/xdp_dummy.o section xdp_dummy 2>/dev/null &&\
+	echo "fail - set operation successful ?!?" || echo " ok "
+
+# the following tests will run with multiple channels active
+ip netns exec $NS_SRC ethtool -L veth$SRC tx 3
+
 ip -n $NS_DST link set dev veth$DST xdp object ../bpf/xdp_dummy.o section xdp_dummy 2>/dev/null
+printf "%-60s" "bad setting: reducing RX nr below peer TX with XDP set"
+ip netns exec $NS_DST ethtool -L veth$DST rx 2 2>/dev/null &&\
+	echo "fail - set operation successful ?!?" || echo " ok "
+printf "%-60s" "bad setting: increasing peer TX nr above RX with XDP set"
+ip netns exec $NS_SRC ethtool -L veth$SRC tx 4 2>/dev/null &&\
+	echo "fail - set operation successful ?!?" || echo " ok "
+
+chk_channels "setting invalid channels nr" $DST 3 4
+
 chk_gro_flag "with xdp attached - gro flag" $DST on
 chk_gro_flag "        - peer gro flag" $SRC off
 chk_tso_flag "        - tso flag" $SRC off
@@ -167,8 +227,13 @@  chk_gro_flag "        - after gro on xdp off, gro flag" $DST on
 chk_gro_flag "        - peer gro flag" $SRC off
 chk_tso_flag "        - tso flag" $SRC on
 chk_tso_flag "        - peer tso flag" $DST on
+
+ip netns exec $NS_DST ethtool -L veth$DST tx 5
+chk_channels "setting tx channels with device down" $DST 3 4
+
 ip -n $NS_DST link set dev veth$DST up
 ip -n $NS_SRC link set dev veth$SRC up
+chk_channels "[takes effect after link up]" $DST 3 5
 chk_gro "        - aggregation" 1
 
 ip netns exec $NS_DST ethtool -K veth$DST gro off