[PATCH] selftests: Update fib_nexthop_multiprefix to handle missing ping6

[David Ahern]

From: David Ahern <dsah...@gmail.com>

Some distributions (e.g., debian buster) do not install ping6. Re-use
the hook in pmtu.sh to detect this and fallback to ping.

Fixes: 735ab2f65dce ("selftests: Add test with multiple prefixes using single 
nexthop")
Signed-off-by: David Ahern <dsah...@gmail.com>
---
 tools/testing/selftests/net/fib_nexthop_multiprefix.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/fib_nexthop_multiprefix.sh 
b/tools/testing/selftests/net/fib_nexthop_multiprefix.sh
index e6828732843e..9dc35a16e415 100755
--- a/tools/testing/selftests/net/fib_nexthop_multiprefix.sh
+++ b/tools/testing/selftests/net/fib_nexthop_multiprefix.sh
@@ -15,6 +15,8 @@
 PAUSE_ON_FAIL=no
 VERBOSE=0
 
+which ping6 > /dev/null 2>&1 && ping6=$(which ping6) || ping6=$(which ping)
+
 
################################################################################
 # helpers
 
@@ -200,7 +202,7 @@ validate_v6_exception()
        local rc
 
        if [ ${ping_sz} != "0" ]; then
-               run_cmd ip netns exec h0 ping6 -s ${ping_sz} -c5 -w5 ${dst}
+               run_cmd ip netns exec h0 ${ping6} -s ${ping_sz} -c5 -w5 ${dst}
        fi
 
        if [ "$VERBOSE" = "1" ]; then
@@ -243,7 +245,7 @@ do
                run_cmd taskset -c ${c} ip netns exec h0 ping -c1 -w1 
172.16.10${i}.1
                [ $? -ne 0 ] && printf "\nERROR: ping to h${i} failed\n" && 
ret=1
 
-               run_cmd taskset -c ${c} ip netns exec h0 ping6 -c1 -w1 
2001:db8:10${i}::1
+               run_cmd taskset -c ${c} ip netns exec h0 ${ping6} -c1 -w1 
2001:db8:10${i}::1
                [ $? -ne 0 ] && printf "\nERROR: ping6 to h${i} failed\n" && 
ret=1
 
                [ $ret -ne 0 ] && break
-- 
2.11.0