1 files changed, 11 insertions, 6 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index e468b7bbb..35e7c2070 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -54,7 +54,7 @@ static const char udhcpc_longopts[] ALIGN1 =
         "foreground\0"     No_argument       "f"
         "background\0"     No_argument       "b"
         "broadcast\0"      No_argument       "B"
-        IF_FEATURE_UDHCPC_ARPING("arping\0"     No_argument       "a")
+        IF_FEATURE_UDHCPC_ARPING("arping\0"     Optional_argument "a")
         IF_FEATURE_UDHCP_PORT("client-port\0"   Required_argument "P")
         ;
 #endif
@@ -1150,7 +1150,7 @@ static void client_background(void)
 //usage:# define IF_UDHCP_VERBOSE(...)
 //usage:#endif
 //usage:#define udhcpc_trivial_usage
-//usage:       "[-fbq"IF_UDHCP_VERBOSE("v")IF_FEATURE_UDHCPC_ARPING("a")"RB] [-t N] [-T SEC] [-A SEC/-n]\n"
+//usage:       "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
 //usage:       "        [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
 //usage:       "        [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
 //usage:#define udhcpc_full_usage "\n"
@@ -1174,7 +1174,7 @@ static void client_background(void)
 //usage:        )
 //usage:     "\n        -S,--syslog             Log to syslog too"
 //usage:        IF_FEATURE_UDHCPC_ARPING(
-//usage:     "\n        -a,--arping             Use arping to validate offered address"
+//usage:     "\n        -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
 //usage:        )
 //usage:     "\n        -r,--request IP         Request this IP address"
 //usage:     "\n        -o,--no-default-options Don't request any options (unless -O is given)"
@@ -1211,7 +1211,7 @@ static void client_background(void)
 //usage:        )
 //usage:     "\n        -S              Log to syslog too"
 //usage:        IF_FEATURE_UDHCPC_ARPING(
-//usage:     "\n        -a              Use arping to validate offered address"
+//usage:     "\n        -a[MSEC]        Validate offered address with ARP ping"
 //usage:        )
 //usage:     "\n        -r IP           Request this IP address"
 //usage:     "\n        -o              Don't request any options (unless -O is given)"
@@ -1238,6 +1238,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 {
         uint8_t *message;
         const char *str_V, *str_h, *str_F, *str_r;
+        IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
         IF_FEATURE_UDHCP_PORT(char *str_P;)
         void *clientid_mac_ptr;
         llist_t *list_O = NULL;
@@ -1252,6 +1253,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         int timeout; /* must be signed */
         unsigned already_waited_sec;
         unsigned opt;
+        IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
         int max_fd;
         int retval;
         fd_set rfds;
@@ -1269,7 +1271,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
         opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
                 USE_FOR_MMU("b")
-                IF_FEATURE_UDHCPC_ARPING("a")
+                IF_FEATURE_UDHCPC_ARPING("a::")
                 IF_FEATURE_UDHCP_PORT("P:")
                 "v"
                 , &str_V, &str_h, &str_h, &str_F
@@ -1278,6 +1280,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
                 , &list_O
                 , &list_x
+                IF_FEATURE_UDHCPC_ARPING(, &str_a)
                 IF_FEATURE_UDHCP_PORT(, &str_P)
                 IF_UDHCP_VERBOSE(, &dhcp_verbose)
         );
@@ -1309,6 +1312,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 SERVER_PORT = CLIENT_PORT - 1;
         }
 #endif
+        IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
         while (list_O) {
                 char *optstr = llist_pop(&list_O);
                 unsigned n = bb_strtou(optstr, NULL, 0);
@@ -1726,7 +1730,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                         NULL,
                                                         (uint32_t) 0,
                                                         client_config.client_mac,
-                                                        client_config.interface)
+                                                        client_config.interface,
+                                                        arpping_ms)
                                         ) {
                                                 bb_info_msg("Offered address is in use "
                                                         "(got ARP reply), declining");