[PATCH net-next 4/5] selftests: mptcp: convert iptables to nftables for mptcp_sockopt.sh

[Matthieu Baerts (NGI0)]

From: Hangbin Liu <liuhangbin@xxxxxxxxxx>

During the conversion, we retain the same filter and chain names previously
used by iptables/ip6tables. Counters are not added to accept rules because
the test does not inspect them. After conversion, the generated output
matches the original iptables/ip6tables behavior.

Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
To: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
---
 tools/testing/selftests/net/mptcp/mptcp_lib.sh     |  2 +-
 tools/testing/selftests/net/mptcp/mptcp_sockopt.sh | 58 ++++++++++++----------
 2 files changed, 34 insertions(+), 26 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
index b9d14647f401..e65b4ebee06a 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
@@ -528,7 +528,7 @@ mptcp_lib_check_tools() {
 				exit ${KSFT_SKIP}
 			fi
 			;;
-		"iptables"* | "ip6tables"*)
+		"iptables"* | "ip6tables"* | "nft" | "jq")
 			if ! "${tool}" -V &> /dev/null; then
 				mptcp_lib_pr_skip "Could not run all tests without ${tool}"
 				exit ${KSFT_SKIP}
diff --git a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
index e850a87429b6..b4e3eddc9cf2 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_sockopt.sh
@@ -15,8 +15,6 @@ cin=""
 cout=""
 timeout_poll=30
 timeout_test=$((timeout_poll * 2 + 1))
-iptables="iptables"
-ip6tables="ip6tables"
 
 ns1=""
 ns2=""
@@ -49,16 +47,27 @@ add_mark_rules()
 	local ns=$1
 	local m=$2
 
-	local t
-	for t in ${iptables} ${ip6tables}; do
-		# just to debug: check we have multiple subflows connection requests
-		ip netns exec $ns $t -A OUTPUT -p tcp --syn -m mark --mark $m -j ACCEPT
+	local table
+	for table in ip ip6; do
+		ip netns exec "$ns" nft -f - <<-EOF
+			add table $table filter
+			add chain $table filter OUTPUT \
+				{ type filter hook output priority 0; policy accept; }
 
-		# RST packets might be handled by a internal dummy socket
-		ip netns exec $ns $t -A OUTPUT -p tcp --tcp-flags RST RST -m mark --mark 0 -j ACCEPT
+			# just to debug: check we have multiple subflows connection requests
+			add rule $table filter OUTPUT \
+				tcp flags & (fin | syn | rst | ack) == syn \
+				meta mark $m accept
 
-		ip netns exec $ns $t -A OUTPUT -p tcp -m mark --mark $m -j ACCEPT
-		ip netns exec $ns $t -A OUTPUT -p tcp -m mark --mark 0 -j DROP
+			# RST packets might be handled by a internal dummy socket
+			add rule $table filter OUTPUT \
+				tcp flags & rst == rst meta mark 0x0 accept
+
+			add rule $table filter OUTPUT \
+				meta l4proto tcp meta mark $m accept
+			add rule $table filter OUTPUT \
+				meta l4proto tcp meta mark 0 counter drop
+		EOF
 	done
 }
 
@@ -105,32 +114,31 @@ cleanup()
 
 mptcp_lib_check_mptcp
 mptcp_lib_check_kallsyms
-mptcp_lib_check_tools ip "${iptables}" "${ip6tables}"
+mptcp_lib_check_tools ip nft jq
 
 check_mark()
 {
 	local ns=$1
 	local af=$2
 
-	local tables=${iptables}
+	local tables="ip"
 
 	if [ $af -eq 6 ];then
-		tables=${ip6tables}
+		tables="ip6"
 	fi
 
-	local counters values
-	counters=$(ip netns exec $ns $tables -v -L OUTPUT | grep DROP)
-	values=${counters%DROP*}
+	local drops
+	drops=$(ip netns exec "$ns" nft -j list table "$tables" filter | \
+		jq '.nftables[] | select(has("rule")) | .rule |
+			select (.chain=="OUTPUT" and any(.expr[]; has("drop"))) |
+			.expr[] | select(has("counter")) | .counter.packets')
 
-	local v
-	for v in $values; do
-		if [ $v -ne 0 ]; then
-			mptcp_lib_pr_fail "got $tables $values in ns $ns," \
-					  "not 0 - not all expected packets marked"
-			ret=${KSFT_FAIL}
-			return 1
-		fi
-	done
+	if [ -z "$drops" ] || [ "$drops" -ne 0 ]; then
+		mptcp_lib_pr_fail "got $tables $drops in ns $ns," \
+				  "not 0 - not all expected packets marked"
+		ret=${KSFT_FAIL}
+		return 1
+	fi
 
 	return 0
 }

-- 
2.55.0