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>

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 7b679d1..cef0ab9 100644 (file)
--- 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;