[PATCH net-next v8 08/14] selftests/vsock: add namespace helpers to vmtest.sh

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Bobby Eshleman <bobbyeshleman@meta.com>

Add functions for initializing namespaces with the different vsock NS
modes. Callers can use add_namespaces() and del_namespaces() to create
namespaces global0, global1, local0, and local1.

The init_namespaces() function initializes global0, local0, etc...  with
their respective vsock NS mode. This function is separate so that tests
that depend on this initialization can use it, while other tests that
want to test the initialization interface itself can start with a clean
slate by omitting this call.

Remove namespaces upon exiting the program in cleanup().  This is
unlikely to be needed for a healthy run, but it is useful for tests that
are manually killed mid-test. In that case, this patch prevents the
subsequent test run from finding stale namespaces with
already-write-once-locked vsock ns modes.

This patch is in preparation for later namespace tests.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 tools/testing/selftests/vsock/vmtest.sh | 45 +++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
index 62b4f5ede9f6..5f4bae952e13 100755
--- a/tools/testing/selftests/vsock/vmtest.sh
+++ b/tools/testing/selftests/vsock/vmtest.sh
@@ -46,6 +46,7 @@ readonly TEST_DESCS=(
 )
 
 readonly USE_SHARED_VM=(vm_server_host_client vm_client_host_server vm_loopback)
+readonly NS_MODES=("local" "global")
 
 VERBOSE=0
 
@@ -100,11 +101,55 @@ check_result() {
 	cnt_total=$(( cnt_total + 1 ))
 }
 
+add_namespaces() {
+	# add namespaces local0, local1, global0, and global1
+	for mode in "${NS_MODES[@]}"; do
+		ip netns add "${mode}0" 2>/dev/null
+		ip netns add "${mode}1" 2>/dev/null
+	done
+}
+
+init_namespaces() {
+	for mode in "${NS_MODES[@]}"; do
+		ns_set_mode "${mode}0" "${mode}"
+		ns_set_mode "${mode}1" "${mode}"
+
+		log_host "set ns ${mode}0 to mode ${mode}"
+		log_host "set ns ${mode}1 to mode ${mode}"
+
+		# we need lo for qemu port forwarding
+		ip netns exec "${mode}0" ip link set dev lo up
+		ip netns exec "${mode}1" ip link set dev lo up
+	done
+}
+
+del_namespaces() {
+	for mode in "${NS_MODES[@]}"; do
+		ip netns del "${mode}0" &>/dev/null
+		ip netns del "${mode}1" &>/dev/null
+		log_host "removed ns ${mode}0"
+		log_host "removed ns ${mode}1"
+	done
+}
+
+ns_set_mode() {
+	local ns=$1
+	local mode=$2
+
+	echo "${mode}" | ip netns exec "${ns}" \
+		tee /proc/sys/net/vsock/ns_mode &>/dev/null
+}
+
 vm_ssh() {
 	ssh -q -o UserKnownHostsFile=/dev/null -p ${SSH_HOST_PORT} localhost "$@"
 	return $?
 }
 
+cleanup() {
+	del_namespaces
+}
+
+trap cleanup EXIT
 
 check_args() {
 	local found

-- 
2.47.3