selftests: mptcp: move stats info in case of errors to lib.sh

A few MPTCP selftests are using the same code to print stats in case of
error. This code can then be moved to mptcp_lib.sh.

No behaviour changes intended, except to print the error in red and to
stderr, like most error messages.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250114-net-next-mptcp-st-more-debug-err-v1-3-2ffb16a6cf35@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/mptcp/mptcp_connect.sh

@@ -445,12 +445,8 @@ do_transfer()
 	printf "(duration %05sms) " "${duration}"
 	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
 		mptcp_lib_pr_fail "client exit code $retc, server $rets"
-		echo -e "\nnetns ${listener_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${listener_ns} ss -Menita 1>&2 -o "sport = :$port"
-		cat /tmp/${listener_ns}.out
-		echo -e "\nnetns ${connector_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${connector_ns} ss -Menita 1>&2 -o "dport = :$port"
-		[ ${listener_ns} != ${connector_ns} ] && cat /tmp/${connector_ns}.out
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
+			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
 
 		echo
 		cat "$capout"

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -1039,13 +1039,8 @@ do_transfer()
 
 	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
 		fail_test "client exit code $retc, server $rets"
-		echo -e "\nnetns ${listener_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${listener_ns} ss -Menita 1>&2 -o "sport = :$port"
-		cat /tmp/${listener_ns}.out
-		echo -e "\nnetns ${connector_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${connector_ns} ss -Menita 1>&2 -o "dport = :$port"
-		cat /tmp/${connector_ns}.out
-
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
+			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
 		return 1
 	fi
 

tools/testing/selftests/net/mptcp/mptcp_lib.sh

@@ -107,6 +107,27 @@ mptcp_lib_pr_info() {
 	mptcp_lib_print_info "INFO: ${*}"
 }
 
+# $1-2: listener/connector ns ; $3 port ; $4-5 listener/connector stat file
+mptcp_lib_pr_err_stats() {
+	local lns="${1}"
+	local cns="${2}"
+	local port="${3}"
+	local lstat="${4}"
+	local cstat="${5}"
+
+	echo -en "${MPTCP_LIB_COLOR_RED}"
+	{
+		printf "\nnetns %s (listener) socket stat for %d:\n" "${lns}" "${port}"
+		ip netns exec "${lns}" ss -Menita -o "sport = :${port}"
+		cat "${lstat}"
+
+		printf "\nnetns %s (connector) socket stat for %d:\n" "${cns}" "${port}"
+		ip netns exec "${cns}" ss -Menita -o "dport = :${port}"
+		[ "${lstat}" != "${cstat}" ] && cat "${cstat}"
+	} 1>&2
+	echo -en "${MPTCP_LIB_COLOR_RESET}"
+}
+
 # SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES env var can be set when validating all
 # features using the last version of the kernel and the selftests to make sure
 # a test is not being skipped by mistake.

tools/testing/selftests/net/mptcp/mptcp_sockopt.sh

@@ -202,12 +202,8 @@ do_transfer()
 	print_title "Transfer ${ip:2}"
 	if [ ${rets} -ne 0 ] || [ ${retc} -ne 0 ]; then
 		mptcp_lib_pr_fail "client exit code $retc, server $rets"
-		echo -e "\nnetns ${listener_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${listener_ns} ss -Menita 1>&2 -o "sport = :$port"
-		cat /tmp/${listener_ns}.out
-		echo -e "\nnetns ${connector_ns} socket stat for ${port}:" 1>&2
-		ip netns exec ${connector_ns} ss -Menita 1>&2 -o "dport = :$port"
-		cat /tmp/${connector_ns}.out
+		mptcp_lib_pr_err_stats "${listener_ns}" "${connector_ns}" "${port}" \
+			"/tmp/${listener_ns}.out" "/tmp/${connector_ns}.out"
 
 		mptcp_lib_result_fail "transfer ${ip}"
 

tools/testing/selftests/net/mptcp/simult_flows.sh

@@ -204,12 +204,8 @@ do_transfer()
 	fi
 
 	mptcp_lib_pr_fail "client exit code $retc, server $rets"
-	echo -e "\nnetns ${ns3} socket stat for $port:" 1>&2
-	ip netns exec ${ns3} ss -Menita 1>&2 -o "sport = :$port"
-	cat /tmp/${ns3}.out
-	echo -e "\nnetns ${ns1} socket stat for $port:" 1>&2
-	ip netns exec ${ns1} ss -Menita 1>&2 -o "dport = :$port"
-	cat /tmp/${ns1}.out
+	mptcp_lib_pr_err_stats "${ns3}" "${ns1}" "${port}" \
+		"/tmp/${ns3}.out" "/tmp/${ns1}.out"
 	ls -l $sin $cout
 	ls -l $cin $sout