udhcpc: exit if iface disappeared; use correct MAC if it changes

function                                             old     new   delta
udhcpc_main                                         2560    2618     +58

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 6 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 7b679d10f..cef0ab957 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -928,6 +928,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         uint8_t *temp, *message;
         const char *str_V, *str_h, *str_F, *str_r;
         IF_FEATURE_UDHCP_PORT(char *str_P;)
+        void *clientid_mac_ptr;
         llist_t *list_O = NULL;
         llist_t *list_x = NULL;
         int tryagain_timeout = 20;
@@ -1004,7 +1005,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 IF_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
         };
 
-        /* Default options. */
+        /* Default options */
         IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
         IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
         client_config.interface = "eth0";
@@ -1086,11 +1087,13 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 return 1;
         }
 
+        clientid_mac_ptr = NULL;
         if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
                 /* not suppressed and not set, set the default client ID */
                 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
                 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
-                memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
+                clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
+                memcpy(clientid_mac_ptr, client_config.client_mac, 6);
         }
         if (str_V[0] != '\0')
                 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
@@ -1173,10 +1176,15 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                          * or if the status of the bridge changed).
                          * Refresh ifindex and client_mac:
                          */
-                        udhcp_read_interface(client_config.interface,
-                                &client_config.ifindex,
-                                NULL,
-                                client_config.client_mac);
+                        if (udhcp_read_interface(client_config.interface,
+                                        &client_config.ifindex,
+                                        NULL,
+                                        client_config.client_mac)
+                        ) {
+                                return 1; /* iface is gone? */
+                        }
+                        if (clientid_mac_ptr)
+                                memcpy(clientid_mac_ptr, client_config.client_mac, 6);
 
                         /* We will restart the wait in any case */
                         already_waited_sec = 0;