udhcpc: add -N option

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 3be09f4..c2af4bc 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -49,6 +49,7 @@ static const char udhcpc_longopts[] ALIGN1 =
 	"version\0"        No_argument       "v"
 	"retries\0"        Required_argument "t"
 	"tryagain\0"       Required_argument "A"
+	"renew-timeout\0"  Required_argument "N"
 	"syslog\0"         No_argument       "S"
 	"request-option\0" Required_argument "O"
 	"no-default-options\0" No_argument   "o"
@@ -82,8 +83,9 @@ enum {
 	OPT_x = 1 << 18,
 	OPT_f = 1 << 19,
 	OPT_B = 1 << 20,
+	OPT_N = 1 << 21,
 /* The rest has variable bit positions, need to be clever */
-	OPTBIT_B = 20,
+	OPTBIT_N = 21,
 	USE_FOR_MMU(             OPTBIT_b,)
 	IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
 	IF_FEATURE_UDHCP_PORT(   OPTBIT_P,)
@@ -969,6 +971,7 @@ static void client_background(void)
 //usage:     "\n	-t,--retries N		Send up to N discover packets"
 //usage:     "\n	-T,--timeout N		Pause between packets (default 3 seconds)"
 //usage:     "\n	-A,--tryagain N		Wait N seconds after failure (default 20)"
+//usage:     "\n	-N,--renew-timeout N	Wait N seconds for requested renew"
 //usage:     "\n	-f,--foreground		Run in foreground"
 //usage:	USE_FOR_MMU(
 //usage:     "\n	-b,--background		Background if lease is not obtained"
@@ -1007,6 +1010,7 @@ static void client_background(void)
 //usage:     "\n	-t N		Send up to N discover packets"
 //usage:     "\n	-T N		Pause between packets (default 3 seconds)"
 //usage:     "\n	-A N		Wait N seconds (default 20) after failure"
+//usage:     "\n	-N N		Wait N seconds for requested renew"
 //usage:     "\n	-f		Run in foreground"
 //usage:	USE_FOR_MMU(
 //usage:     "\n	-b		Background if lease is not obtained"
@@ -1054,6 +1058,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 	int tryagain_timeout = 20;
 	int discover_timeout = 3;
 	int discover_retries = 3;
+	int renew_timeout = 0;
 	uint32_t server_addr = server_addr; /* for compiler */
 	uint32_t requested_ip = 0;
 	uint32_t xid = 0;
@@ -1077,13 +1082,13 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 
 	/* Parse command line */
 	/* O,x: list; -T,-t,-A take numeric param */
-	opt_complementary = "O::x::T+:t+:A+"
+	opt_complementary = "O::x::T+:t+:A+:N+"
 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 		":vv"
 #endif
 		;
 	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"
+	opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fBN:"
 		USE_FOR_MMU("b")
 		IF_FEATURE_UDHCPC_ARPING("a")
 		IF_FEATURE_UDHCP_PORT("P:")
@@ -1094,6 +1099,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		, &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
 		, &list_O
 		, &list_x
+		, &renew_timeout /* N */
 		IF_FEATURE_UDHCP_PORT(, &str_P)
 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 		, &dhcp_verbose
@@ -1362,8 +1368,15 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		case SIGUSR1:
 			client_config.first_secs = 0; /* make secs field count from 0 */
 			perform_renew();
-			if (state == RENEW_REQUESTED)
+			if (state == RENEW_REQUESTED) {
+				/* We will probably restart the wait */
+				timeout -= already_waited_sec;
+				already_waited_sec = 0;
+				/* Use user supplied timeout */
+				if (renew_timeout && timeout > renew_timeout)
+					timeout = renew_timeout;
 				goto case_RENEW_REQUESTED;
+			}
 			/* Start things over */
 			packet_num = 0;
 			/* Kill any timeouts, user wants this to hurry along */