tutorials/mtu: move NS and iface logic to common

Move logic to check for NSs and interfaces into common.sh so that
it can be used by other scripts.

Author: msune

tutorials/net/mtu/.bashrc

@@ -1,3 +1,5 @@
+source /bp/common.sh
+
 SCENARIO="error"
 if [ -f /bp/.scenario ]; then
     SCENARIO=$(< /bp/.scenario)
@@ -24,13 +26,6 @@ alias _exec='exec'
 alias help="/bp/help.sh"
 alias describe="/bp/describe.sh"
 
-_check_ns(){
-	if ! ip netns list | grep -qw ${1}; then
-		echo "Invalid namespace: '${1}'"
-		return 1
-	fi
-}
-
 exec(){
 	if [ -z "${1:-}" ] || [ -z "${2:-}" ] ; then
 		echo "Usage: exec <namespace_name> <command>"
@@ -43,7 +38,7 @@ exec(){
 }
 
 export IGNOREEOF=3
-exit() {
+exit(){
 	if [ "${NS}" != "" ]; then
 		builtin exit;
 	fi
@@ -66,7 +61,7 @@ shell(){
 	ip netns exec ${1} bash --rcfile /bp/.bashrc -i
 }
 
-_shell_completion() {
+_shell_completion(){
 	local cur
 	cur="${COMP_WORDS[COMP_CWORD]}"
 	local namespaces=($(ip netns list | awk '{print $1}'))

tutorials/net/mtu/common.sh

@@ -24,6 +24,35 @@ log_debug(){
 	_log "DBG" "${1}"
 }
 
+# $1 namespace name
+_check_ns(){
+	if ! ${SUDO} ip netns exec ${1} true >/dev/null 2>&1 ; then
+		log_err "Invalid namespace: '${1}'"
+		return 1
+	fi
+}
+
+# $1 namespace
+# $2 iface
+_check_ns_iface(){
+	if ! ${SUDO} ip netns exec ${1} ip link show dev ${2} >/dev/null 2>&1 ; then
+		log_err "Invalid iface: '${2}' in namespace '${1}'!"
+		return 1
+	fi
+
+}
+
+# Parses namespace and interface
+# and sets them to CMD_NS and CMD_IFACE
+# $1 namespace.interface
+_parse_ns_iface(){
+	CMD_NS="$(echo ${1} | awk -F. '{print $1}')"
+	CMD_IFACE="$(echo ${1} | awk -F. '{print $2}')"
+	echo "Checking ${CMD_NS} and ${CMD_IFACE}"
+	_check_ns ${CMD_NS}
+	_check_ns_iface ${CMD_NS} ${CMD_IFACE}
+}
+
 # $1 namespace name
 create_ns() {
 	${SUDO} ip netns add ${1}

tutorials/net/mtu/describe.sh

@@ -16,14 +16,14 @@ echo""
 
 cat /bp/${SCENARIO}/TOPOLOGY.md
 echo""
-for ns in $(ip netns list | awk '{print $1}'); do
+for ns in $(${SUDO} ip netns list | awk '{print $1}'); do
 	echo "================================================="
 	echo -e "\033[1;34mNamespace: $ns\033[0m"
 	echo "-------------------------------------------------"
 	echo "IP addressing:"
-	ip netns exec ${ns} ip -brief addr
+	${SUDO} ip netns exec ${ns} ip -brief addr
 	echo ""
 	echo "Routing table:"
-	ip netns exec ${ns} ip -brief route
+	${SUDO} ip netns exec ${ns} ip -brief route
 	echo -e "\n"
 done