From d09e94fff82440cedf04f2e0cfe1ede8a0ab0600 Mon Sep 17 00:00:00 2001
From: Steven Barth <steven@midlink.org>
Date: Sun, 5 May 2013 15:56:42 +0200
Subject: [PATCH] Set a global default DHCPv6 exchange timeout

This delays SLAAC-updates before any DHCPv6-binding is established.
---
 src/odhcp6c.c | 23 +++++++++++------------
 src/odhcp6c.h |  1 +
 src/script.c  | 23 +++++++++++++++++++++++
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index a97e4c9..6ce9adf 100644
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -40,8 +40,8 @@ static uint8_t *state_data[_STATE_MAX] = {NULL};
 static size_t state_len[_STATE_MAX] = {0};
 
 static volatile int do_signal = 0;
-static int urandom_fd = -1;
-static bool bound = false, allow_slaac_only = true, release = true;
+static int urandom_fd = -1, allow_slaac_only = 15;
+static bool bound = false, release = true;
 
 
 int main(_unused int argc, char* const argv[])
@@ -58,10 +58,10 @@ int main(_unused int argc, char* const argv[])
 	bool help = false, daemonize = false;
 	int logopt = LOG_PID;
 	int c, request_pd = 0;
-	while ((c = getopt(argc, argv, "SN:P:c:r:s:khedp:")) != -1) {
+	while ((c = getopt(argc, argv, "S::N:P:c:r:s:khedp:")) != -1) {
 		switch (c) {
 		case 'S':
-			allow_slaac_only = false;
+			allow_slaac_only = (optarg) ? atoi(optarg) : -1;
 			break;
 
 		case 'N':
@@ -76,7 +76,6 @@ int main(_unused int argc, char* const argv[])
 			break;
 
 		case 'P':
-			allow_slaac_only = false;
 			request_pd = strtoul(optarg, NULL, 10);
 			if (request_pd == 0)
 				request_pd = -1;
@@ -307,7 +306,7 @@ static int usage(void)
 	const char buf[] =
 	"Usage: odhcp6c [options] <interface>\n"
 	"\nFeature options:\n"
-	"	-S		Don't allow SLAAC-only (implied by -P)\n"
+	"	-S <time>	Wait at least <time> sec for a DHCP-server (15)\n"
 	"	-N <mode>	Mode for requesting addresses [try|force|none]\n"
 	"	-P <length>	Request IPv6-Prefix (0 = auto)\n"
 	"	-c <clientid>	Override client-ID (base-16 encoded)\n"
@@ -355,12 +354,12 @@ bool odhcp6c_signal_process(void)
 {
 	if (do_signal == SIGIO) {
 		do_signal = 0;
-		bool updated = ra_process();
-		updated |= ra_rtnl_process();
-		if (updated && (bound || allow_slaac_only)) {
-			odhcp6c_expire();
-			script_call("ra-updated");
-		}
+		bool ra_updated = ra_process();
+
+		if (ra_rtnl_process() || (ra_updated && (bound || allow_slaac_only == 0)))
+			script_call("ra-updated"); // Immediate process urgent events
+		else if (ra_updated && !bound && allow_slaac_only > 0)
+			script_delay_call("ra-updated", allow_slaac_only);
 	}
 
 	return do_signal != 0;
diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index fd3b07a..cfd1a53 100644
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -224,6 +224,7 @@ int set_rtnetlink_addr(int ifindex, const struct in6_addr *addr,
 int script_init(const char *path, const char *ifname);
 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src);
 void script_call(const char *status);
+void script_delay_call(const char *status, int timeout);
 
 bool odhcp6c_signal_process(void);
 uint64_t odhcp6c_get_milli_time(void);
diff --git a/src/script.c b/src/script.c
index ffb39f3..a56d9b4 100644
--- a/src/script.c
+++ b/src/script.c
@@ -17,6 +17,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <syslog.h>
+#include <signal.h>
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <netinet/in.h>
@@ -38,6 +39,7 @@ static const int8_t hexvals[] = {
 
 
 static char *argv[4] = {NULL, NULL, NULL, NULL};
+static volatile char *delayed_call = NULL;
 
 
 int script_init(const char *path, const char *ifname)
@@ -176,11 +178,32 @@ static void entry_to_env(const char *name, const void *data, size_t len, enum en
 }
 
 
+static void script_call_delayed(int signal __attribute__((unused)))
+{
+	if (delayed_call)
+		script_call((char*)delayed_call);
+}
+
+
+void script_delay_call(const char *status, int timeout)
+{
+	if (!delayed_call) {
+		delayed_call = strdup(status);
+		signal(SIGALRM, script_call_delayed);
+		alarm(timeout);
+	}
+}
+
+
 void script_call(const char *status)
 {
 	size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 	size_t sip_ip_len, sip_fqdn_len;
 
+	odhcp6c_expire();
+	if (delayed_call)
+		alarm(0);
+
 	struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 	uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 	uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
-- 
2.39.2