I cleared IFF_NOARP flag from netdevsim dev->flags in order to support
skb forwarding. This breaks the rtnetlink.sh selftest
kci_test_ipsec_offload() test because ipsec does not connect to peers it
cannot transmit to.

Fix the issue by adding a neigh entry manually. ipsec_offload test now
successfully pass.

❯❯❯ sudo ./rtnetlink.sh
PASS: policy routing
PASS: route get
PASS: preferred_lft addresses have expired
PASS: promote_secondaries complete
PASS: tc htb hierarchy
PASS: gre tunnel endpoint
PASS: gretap
PASS: ip6gretap
PASS: erspan
PASS: ip6erspan
PASS: bridge setup
PASS: ipv6 addrlabel
PASS: set ifalias 7a28dcd6-7fc3-4499-9f58-9f85d34eb328 for test-dummy0
FAIL: can't add vrf interface, skipping test
FAIL: can't add macsec interface, skipping test
FAIL: macsec_offload netdevsim doesn't support MACsec offload
PASS: ipsec
./rtnetlink.sh: line 756: echo: write error: No space left on device
PASS: ipsec_offload
FAIL: bridge fdb get
PASS: neigh get
PASS: bridge_parent_id
PASS: address proto IPv4
PASS: address proto IPv6
PASS: enslave interface in a bond

Signed-off-by: David Wei <redacted>
---
 tools/testing/selftests/net/rtnetlink.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/net/rtnetlink.sh b/tools/testing/selftests/net/rtnetlink.sh
index 874a2952aa8e..bdf6f10d0558 100755
--- a/tools/testing/selftests/net/rtnetlink.sh
+++ b/tools/testing/selftests/net/rtnetlink.sh

@@ -801,6 +801,8 @@ kci_test_ipsec_offload()
 		end_test "FAIL: ipsec_offload SA offload missing from list output"
 	fi
 
+	# we didn't create a peer, make sure we can Tx
+	ip neigh add $dstip dev $dev lladdr 00:11:22:33:44:55
 	# use ping to exercise the Tx path
 	ping -I $dev -c 3 -W 1 -i 0 $dstip >/dev/null
 

-- 
2.39.3