From 1b320f2dd24d075410bc595a6d3b21e303e4883f Mon Sep 17 00:00:00 2001
From: Denton Gentry <dgentry@google.com>
Date: Sun, 1 Jul 2012 23:56:59 -0700
Subject: [PATCH] Allow for a minimum IRT for DHCP6.

+ DHCP6 servers which do not include an INFORMATION_REFRESH_TIME
  option are effectively saying the information in the DHCP6 response
  is valid indefinitely.
+ dhclient will exit, as it would never need to send another request.
+ Information is *never* valid forever, even if the server thinks it is.

+ --never-gonna-give-you-up <seconds> imposes a refresh interval
    even if the server did not state one.

+ it also Rickrolls the rest of the team.
---
 client/dhc6.c     |    9 ++++++---
 client/dhclient.c |   23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/client/dhc6.c b/client/dhc6.c
index 24f3f18..b90d2f1 100644
--- a/client/dhc6.c
+++ b/client/dhc6.c
@@ -116,6 +116,7 @@ static int check_timing6(struct client_state *client, u_int8_t msg_type,
 
 extern int onetry;
 extern int stateless;
+extern int force_default_irt;
 
 /*
  * The "best" default DUID, since we cannot predict any information
@@ -4805,9 +4806,11 @@ dhc6_check_irt(struct client_state *client)
 			break;
 		}
 	}
-	/* Simply return gives a endless loop waiting for nothing. */
-	if (!found)
+
+	if (!found && !force_default_irt) {
+		/* Simply return gives a endless loop waiting for nothing. */
 		exit(0);
+	}
 
 	oc = lookup_option(&dhcpv6_universe, client->active_lease->options,
 			   D6O_INFORMATION_REFRESH_TIME);
@@ -4829,7 +4832,7 @@ dhc6_check_irt(struct client_state *client)
 		}
 		data_string_forget(&irt, MDL);
 	} else
-		expire = IRT_DEFAULT;
+		expire = force_default_irt ? force_default_irt : IRT_DEFAULT;
 
 	if (expire != MAX_TIME) {
 		log_debug("PRC: Refresh event scheduled in %u seconds.",
diff --git a/client/dhclient.c b/client/dhclient.c
index 1209a96..7a6bc09 100644
--- a/client/dhclient.c
+++ b/client/dhclient.c
@@ -40,6 +40,7 @@
 
 TIME default_lease_time = 43200; /* 12 hours... */
 TIME max_lease_time = 86400; /* 24 hours... */
+int force_default_irt = 0;
 
 const char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
 const char *path_dhclient_db = NULL;
@@ -97,6 +98,7 @@ static int check_domain_name(const char *ptr, size_t len, int dots);
 static int check_domain_name_list(const char *ptr, size_t len, int dots);
 static int check_option_values(struct universe *universe, unsigned int opt,
 			       const char *ptr, size_t len);
+static int validate_irt(const char *irt);
 
 int
 main(int argc, char **argv) {
@@ -289,6 +291,10 @@ main(int argc, char **argv) {
 				wanted_ia_na = 0;
 			}
 			wanted_ia_pd++;
+		} else if (!strcmp(argv[i], "--never-gonna-give-you-up")) {
+			if (++i == argc)
+				usage();
+			force_default_irt = validate_irt(argv[i]);
 #endif /* DHCPv6 */
 		} else if (!strcmp(argv[i], "-v")) {
 			quiet = 0;
@@ -694,6 +700,7 @@ static void usage()
 	log_fatal("Usage: dhclient "
 #ifdef DHCPv6
 		  "[-4|-6] [-SNTP1dvrx] [-nw] [-p <port>]\n"
+		  "                [--never-gonna-give-you-up <interval>]\n"
 #else /* DHCPv6 */
 		  "[-1dvrx] [-nw] [-p <port>]\n"
 #endif /* DHCPv6 */
@@ -4106,3 +4113,19 @@ add_reject(struct packet *packet) {
 	 */
 	log_info("Server added to list of rejected servers.");
 }
+
+static int
+validate_irt(const char *irt) {
+	long local_irt = 0;
+	char *endptr;
+
+	errno = 0;
+	local_irt = strtol(irt, &endptr, 10);
+
+	if ((*endptr != '\0') || (errno == ERANGE) || (errno == EINVAL))
+		log_fatal ("Invalid IRT: %s", irt);
+	if (local_irt < IRT_MINIMUM)
+		log_fatal ("Invalid IRT %ld < minimum (%d)", local_irt, IRT_MINIMUM);
+
+	return (int)local_irt;
+}
-- 
1.7.9.4