[master] dhclient now delays between DHCPDECLINE and DHCPDISCOVER

Merges in rt45457

RELNOTES

@@ -187,6 +187,16 @@ dhcp-users@lists.isc.org.
   When used in conjunction with -P, it directs dhclient to use the given
   length as the prefix length hint when requesting prefixes.
  [ISC-Bugs #43792]
+ [ISC-Bugs #35112]
+ [ISC-Bugs #32228]
+ [ISC-Bugs #29470]
+
+- dhclient will now wait for 10 seconds after declining an IPv4 address
+  before issuing a discover.  This is in keeping with RFC 2131, section 3.1.5.
+  Prior to this dhclient did not wait at all. The amount of time dhclient
+  waits can be specified via a new command line parameter:
+  --decline-wait-time <seconds>.  A value of zero equates to no wait at all.
+  [ISC-Bugs #45457]
 
 			Changes since 4.3.0 (bug fixes)
 

client/dhclient.8

@@ -142,6 +142,10 @@ dhclient - Dynamic Host Configuration Protocol Client
 .I length
 ]
 [
+.B --decline-wait-time
+.I seconds
+]
+[
 .B -v
 ]
 [
@@ -365,6 +369,13 @@ client id in this fashion is discouraged.
 .BI \-I
 Use the standard DDNS scheme from RFCs 4701 & 4702.
 .TP
+.TP
+.BI \--decline-wait-time \ seconds
+Specify the time (in seconds) that an IPv4 client should wait after
+declining an address before issuing a discover.  The default is
+10 seconds as recommended by RFC 2131, Section 3.1.5.  A value of
+zero equates to no wait at all.
+.PP
 .BI \--version
 Print version number and exit.
 .PP

client/dhclient.c

@@ -68,6 +68,8 @@ int duid_type = 0;
 int duid_v4 = 0;
 int std_dhcid = 0;
 
+int decline_wait_time = 10; /* Default to 10 secs per, RFC 2131, 3.1.5 */
+
 /* ASSERT_STATE() does nothing now; it used to be
    assert (state_is == state_shouldbe). */
 #define ASSERT_STATE(state_is, state_shouldbe) {}
@@ -159,17 +161,19 @@ static const char use_v6command[] = "Command not used for DHCPv4: %s";
 #ifdef DHCPv6
 #ifdef DHCP4o6
 #define DHCLIENT_USAGE0 \
-"[-4|-6] [-SNTPRI1dvrxi] [-nw] -4o6 <port>] [-p <port>]\n" \
+"[-4|-6] [-SNTPRI1dvrxi] [-nw] -4o6 <port>] [-p <port>] [-D LL|LLT]\n" \
-"                [-D LL|LLT] [--dad-wait-time seconds]\n" \
+"                [--dad-wait-time <seconds>] [--prefix-len-hint <length>]\n" \
-"                [--prefix-len-hint length]\n"
+"                [--decline-wait-time <seconds>]\n"
 #else /* DHCP4o6 */
 #define DHCLIENT_USAGE0 \
 "[-4|-6] [-SNTPRI1dvrxi] [-nw] [-p <port>] [-D LL|LLT]\n" \
-"                [--dad-wait-time seconds] [--prefix-len-hint length]\n"
+"                [--dad-wait-time <seconds>] [--prefix-len-hint <length>]\n" \
+"                [--decline-wait-time <seconds>]\n"
 #endif
 #else /* DHCPv6 */
 #define DHCLIENT_USAGE0 \
-"[-I1dvrxi] [-nw] [-p <port>] [-D LL|LLT] \n"
+"[-I1dvrxi] [-nw] [-p <port>] [-D LL|LLT] \n" \
+"                [--decline-wait-time <seconds>]\n"
 #endif
 
 #define DHCLIENT_USAGEC \
@@ -507,6 +511,18 @@ main(int argc, char **argv) {
 				      argv[i]);
 			}
 #endif /* DHCPv6 */
+		} else if (!strcmp(argv[i], "--decline-wait-time")) {
+			if (++i == argc) {
+				usage(use_noarg, argv[i-1]);
+			}
+
+			errno = 0;
+			decline_wait_time = (int)strtol(argv[i], &s, 10);
+			if (errno || (*s != '\0') ||
+			    (decline_wait_time < 0)) {
+				usage("Invalid value for "
+				      "--decline-wait-time: %s", argv[i]);
+			}
 		} else if (!strcmp(argv[i], "-D")) {
 			duid_v4 = 1;
 			if (++i == argc)
@@ -1511,7 +1527,10 @@ void bind_lease (client)
 #endif
 			finish(2);
 		} else {
-			state_init(client);
+			struct timeval tv;
+			tv.tv_sec = cur_tv.tv_sec + decline_wait_time;
+			tv.tv_usec = cur_tv.tv_usec;
+			add_timeout(&tv, state_init, client, 0, 0);
 			return;
 		}
 	}
@@ -3985,8 +4004,10 @@ void script_init(struct client_state *client, const char *reason,
 
 		client_envadd (client, "", "reason", "%s", reason);
 		client_envadd (client, "", "pid", "%ld", (long int)getpid ());
+#if defined(DHCPv6)
 		client_envadd (client, "", "dad_wait_time", "%ld",
 					   (long int)dad_wait_time);
+#endif
 	}
 }