selftests: mlxsw: Fix mausezahn invocation in ERSPAN scale test

The mirror_gre_scale test creates as many ERSPAN sessions as the underlying
chip supports, and tests that they all work. In order to determine that it
issues a stream of ICMP packets and checks if they are mirrored as
expected.

However, the mausezahn invocation missed the -6 flag to identify the use of
IPv6 protocol, and was sending ICMP messages over IPv6, as opposed to
ICMP6. It also didn't pass an explicit source IP address, which apparently
worked at some point in the past, but does not anymore.

To fix these issues, extend the function mirror_test() in mirror_lib by
detecting the IPv6 protocol addresses, and using a different ICMP scheme.
Fix __mirror_gre_test() in the selftest itself to pass a source IP address.

Signed-off-by: Petr Machata <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/drivers/net/mlxsw/mirror_gre_scale.sh

···
 	sleep 5
 
 	for ((i = 0; i < count; ++i)); do
+		local sip=$(mirror_gre_ipv6_addr 1 $i)::1
 		local dip=$(mirror_gre_ipv6_addr 1 $i)::2
 		local htun=h3-gt6-$i
 		local message
 
 		icmp6_capture_install $htun
-		mirror_test v$h1 "" $dip $htun 100 10
+		mirror_test v$h1 $sip $dip $htun 100 10
 		icmp6_capture_uninstall $htun
 	done
 }

tools/testing/selftests/net/forwarding/mirror_lib.sh

···
 	tc filter del dev $swp1 $direction pref 1000
 }
 
+is_ipv6()
+{
+	local addr=$1; shift
+
+	[[ -z ${addr//[0-9a-fA-F:]/} ]]
+}
+
 mirror_test()
 {
 	local vrf_name=$1; shift
···
 	local pref=$1; shift
 	local expect=$1; shift
 
+	if is_ipv6 $dip; then
+		local proto=-6
+		local type="icmp6 type=128" # Echo request.
+	else
+		local proto=
+		local type="icmp echoreq"
+	fi
+
 	local t0=$(tc_rule_stats_get $dev $pref)
-	$MZ $vrf_name ${sip:+-A $sip} -B $dip -a own -b bc -q \
-	    -c 10 -d 100msec -t icmp type=8
+	$MZ $proto $vrf_name ${sip:+-A $sip} -B $dip -a own -b bc -q \
+	    -c 10 -d 100msec -t $type
 	sleep 0.5
 	local t1=$(tc_rule_stats_get $dev $pref)
 	local delta=$((t1 - t0))