selftests/net: convert test_vxlan_nolocalbypass.sh to run it in unique namespace

Here is the test result after conversion.

]# ./test_vxlan_nolocalbypass.sh
TEST: localbypass enabled [ OK ]
TEST: Packet received by local VXLAN device - localbypass [ OK ]
TEST: localbypass disabled [ OK ]
TEST: Packet not received by local VXLAN device - nolocalbypass [ OK ]
TEST: localbypass enabled [ OK ]
TEST: Packet received by local VXLAN device - localbypass [ OK ]

Tests passed: 6
Tests failed: 0

Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: net: vxlan: Fix selftest regression after changes in iproute2.

The iproute2 output that eventually landed upstream is different than
the one used in this test, resulting in failures. Fix by adjusting the
test to use iproute2's JSON output, which is more stable than regular
output.

Fixes: 305c04189997 ("selftests: net: vxlan: Add tests for vxlan nolocalbypass option.")
Signed-off-by: Vladimir Nikishkin <vladimir@nikishkin.pw>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests: net: vxlan: Add tests for vxlan nolocalbypass option.

Add test to make sure that the localbypass option is on by default.

Add test to change vxlan localbypass to nolocalbypass and check
that packets are delivered to userspace.

Signed-off-by: Vladimir Nikishkin <vladimir@nikishkin.pw>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>