From bbe4c0896d25009a7c86285d2ab024eed4374eea Mon Sep 17 00:00:00 2001
From: Hangbin Liu <liuhangbin@gmail.com>
Date: Thu, 10 Feb 2022 17:50:56 +0800
Subject: [PATCH] selftests: netfilter: disable rp_filter on router
Git-commit: bbe4c0896d25009a7c86285d2ab024eed4374eea
Patch-mainline: v5.17-rc5
References: git-fixes

Some distros may enable rp_filter by default. After ns1 change addr to
10.0.2.99 and set default router to 10.0.2.1, while the connected router
address is still 10.0.1.1. The router will not reply the arp request
from ns1. Fix it by setting the router's veth0 rp_filter to 0.

Before the fix:
  # ./nft_fib.sh
  PASS: fib expression did not cause unwanted packet drops
  Netns nsrouter-HQkDORO2 fib counter doesn't match expected packet count of 1 for 1.1.1.1
  table inet filter {
          chain prerouting {
                  type filter hook prerouting priority filter; policy accept;
                  ip daddr 1.1.1.1 fib saddr . iif oif missing counter packets 0 bytes 0 drop
                  ip6 daddr 1c3::c01d fib saddr . iif oif missing counter packets 0 bytes 0 drop
          }
  }

After the fix:
  # ./nft_fib.sh
  PASS: fib expression did not cause unwanted packet drops
  PASS: fib expression did drop packets for 1.1.1.1
  PASS: fib expression did drop packets for 1c3::c01d

Fixes: 82944421243e ("selftests: netfilter: add fib test case")
Signed-off-by: Yi Chen <yiche@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 tools/testing/selftests/netfilter/nft_fib.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/netfilter/nft_fib.sh b/tools/testing/selftests/netfilter/nft_fib.sh
index 6caf6ac8c285..695a1958723f 100755
--- a/tools/testing/selftests/netfilter/nft_fib.sh
+++ b/tools/testing/selftests/netfilter/nft_fib.sh
@@ -174,6 +174,7 @@ test_ping() {
 ip netns exec ${nsrouter} sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
 ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth0.forwarding=1 > /dev/null
 ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth1.forwarding=1 > /dev/null
+ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth0.rp_filter=0 > /dev/null
 
 sleep 3
 
-- 
2.35.3