[network] Improve dealing with missing interfaces.

When the interface is missing or not yet up we try to
gracefully give it a second try. As sometimes something
like a functionfs using gadget could take a while to get
initialized. Also do not fail on a failure to set up the
dhcp server. Falling back on manual setup is better than
not being able to do so.

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>

src/usb_moded-modesetting.c

@@ -318,6 +318,7 @@ int set_dynamic_mode(void)
 
   struct mode_list_elem *data; 
   int ret = 1;
+  int network = 1;
 
   data = get_usb_mode_data();
 
@@ -377,14 +378,14 @@ int set_dynamic_mode(void)
         system(command);
 #else
 	usb_network_down(data);
-	usb_network_up(data);
+	network = usb_network_up(data);
 #endif /* DEBIAN */
   }
 
   /* Needs to be called before application post synching so
      that the dhcp server has the right config */
   if(data->nat || data->dhcp_server)
-	ret = usb_network_set_up_dhcpd(data);
+	usb_network_set_up_dhcpd(data);
 
   /* no need to execute the post sync if there was an error setting the mode */
   if(data->appsync && !ret)
@@ -395,6 +396,15 @@ int set_dynamic_mode(void)
 	connman_set_tethering(data->connman_tethering, TRUE);
 #endif
 
+  /* try a second time to bring up the network if it failed the first time,
+     this can happen with functionfs based gadgets (which is why we sleep for a bit */
+  if(network != 0)
+  {
+	log_debug("Retry setting up te network\n");
+	sleep(1);
+	usb_network_up(data);
+  }
+
   if(ret)
 	usb_moded_send_error_signal(MODE_SETTING_FAILED);
   return(ret);

src/usb_moded-network.c

@@ -122,8 +122,10 @@ static char* get_interface(struct mode_list_elem *data)
 
   check = check_interface(interface);
   if(check)
+  {
 	log_warning("Configured interface is incorrect, nor does usb0 exists. Check your config!\n");
-  /* TODO: Make it so that interface configuration gets skipped when no usable interface exists */
+	return(0);
+  }
 
   log_debug("interface = %s\n", interface);
   return interface;
@@ -139,6 +141,8 @@ static int set_usb_ip_forward(struct mode_list_elem *data, struct ipforward_data
   char command[128];
 
   interface = get_interface(data);
+  if(interface == NULL)
+	return(1);
   nat_interface = get_network_nat_interface();
   if((nat_interface == NULL) && (ipforward->nat_interface != NULL))
 	nat_interface = strdup(ipforward->nat_interface);
@@ -362,6 +366,8 @@ static int write_udhcpd_conf(struct ipforward_data *ipforward, struct mode_list_
   strcat(ipend, "10");
 
   interface = get_interface(data);
+  if(interface == NULL)
+	return(1);
   /* print all data in the file */
   fprintf(conffile, "start\t%s\n", ipstart);
   fprintf(conffile, "end\t%s\n", ipend);
@@ -1071,6 +1077,9 @@ int usb_network_up(struct mode_list_elem *data)
   ip = get_network_ip();
   gateway = get_network_gateway();
 
+  if(interface == NULL)
+	return(1);
+
   if(ip == NULL)
   {
 	sprintf(command,"ifconfig %s 192.168.2.15", interface);
@@ -1166,6 +1175,8 @@ int usb_network_down(struct mode_list_elem *data)
   char command[128];
 
   interface = get_interface(data);
+  if(interface == NULL)
+	return(0);
 
   sprintf(command, "ifconfig %s down\n", interface);
   system(command);