selftests, bpf: test_lwt_ip_encap: Really disable rp_filter

stable inclusion
from stable-5.10.71
commit f1dd6e10f077cef7f8a073fae759db8e41705ac8
bugzilla: 182981 https://gitee.com/openeuler/kernel/issues/I4I3KD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f1dd6e10f077cef7f8a073fae759db8e41705ac8



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[ Upstream commit 79e2c306 ]

It's not enough to set net.ipv4.conf.all.rp_filter=0, that does not override
a greater rp_filter value on the individual interfaces. We also need to set
net.ipv4.conf.default.rp_filter=0 before creating the interfaces. That way,
they'll also get their own rp_filter value of zero.

Fixes: 0fde56e4 ("selftests: bpf: add test_lwt_ip_encap selftest")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/b1cdd9d469f09ea6e01e9c89a6071c79b7380f89.1632386362.git.jbenc@redhat.com


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>