[posix-host] set network interface name (#4573)

When platform netif is enabled, the TUN device's name should be able to
set from command. This PR use the existing `-I` to allow user provide a
wanted name.

.travis/check-posix-app-pty

@@ -80,6 +80,15 @@ check() {
         OT_CLI_CMD="$(pwd)/$(ls output/posix/*linux*/bin/ot-cli) ${OT_NCP_PATH} ${CORE_PTY}"
     fi
 
+    # Cover setting a valid network interface name.
+    readonly VALID_NETIF_NAME="wan$(date +%H%M%S)"
+    sudo ${OT_CLI_CMD} -I "${VALID_NETIF_NAME}" -n
+
+    # Cover setting a too long(max is 15 characters) network interface name.
+    # Expect exit code to be 2(OT_EXIT_INVALID_ARGUMENTS).
+    readonly INVALID_NETIF_NAME="wan0123456789123"
+    sudo ${OT_CLI_CMD} -I "${INVALID_NETIF_NAME}" -n || test $? = 2
+
     if [[ "${DAEMON}" = 1 ]]; then
         sudo ${OT_CLI_CMD} panid 0xface | grep 'Done' || die 'failed to set panid with ot-ctl'
     fi

src/posix/main.c

@@ -180,7 +180,7 @@ static void PrintUsage(const char *aProgramName, FILE *aStream, int aExitCode)
 
 static void ParseArg(int aArgCount, char *aArgVector[], PosixConfig *aConfig)
 {
-    memset(aConfig, 0, sizeof(PosixConfig));
+    memset(aConfig, 0, sizeof(*aConfig));
 
     aConfig->mPlatformConfig.mSpeedUpFactor      = 1;
     aConfig->mPlatformConfig.mResetRadio         = true;

src/posix/platform/netif.cpp

@@ -384,7 +384,7 @@ exit:
     return;
 }
 
-void platformNetifInit(otInstance *aInstance)
+void platformNetifInit(otInstance *aInstance, const char *aInterfaceName)
 {
     struct ifreq ifr;
 
@@ -410,7 +410,17 @@ void platformNetifInit(otInstance *aInstance)
 
     memset(&ifr, 0, sizeof(ifr));
     ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
-    strncpy(ifr.ifr_name, "wpan%d", IFNAMSIZ);
+
+    if (aInterfaceName)
+    {
+        VerifyOrDie(strlen(aInterfaceName) < IFNAMSIZ, OT_EXIT_INVALID_ARGUMENTS);
+
+        strncpy(ifr.ifr_name, aInterfaceName, IFNAMSIZ);
+    }
+    else
+    {
+        strncpy(ifr.ifr_name, "wpan%d", IFNAMSIZ);
+    }
 
     VerifyOrExit(ioctl(sTunFd, TUNSETIFF, static_cast<void *>(&ifr)) == 0,
                  otLogCritPlat("Unable to configure tun device %s", OPENTHREAD_POSIX_TUN_DEVICE));

src/posix/platform/platform-posix.h

@@ -276,9 +276,10 @@ void platformUartProcess(const fd_set *aReadFdSet, const fd_set *aWriteFdSet, co
  * This function initializes platform netif.
  *
  * @param[in]   aInstance       A pointer to the OpenThread instance.
+ * @param[in]   aInterfaceName  A pointer to Thread network interface name.
  *
  */
-void platformNetifInit(otInstance *aInstance);
+void platformNetifInit(otInstance *aInstance, const char *aInterfaceName);
 
 /**
  * This function updates the file descriptor sets with file descriptors used by platform netif module.

src/posix/platform/system.cpp

@@ -59,7 +59,7 @@ otInstance *otSysInit(otPlatformConfig *aPlatformConfig)
     assert(instance != NULL);
 
 #if OPENTHREAD_CONFIG_PLATFORM_NETIF_ENABLE
-    platformNetifInit(instance);
+    platformNetifInit(instance, aPlatformConfig->mInterfaceName);
 #elif OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE
     platformUdpInit(aPlatformConfig->mInterfaceName);
 #endif