dhcpv6-ia: use dhcp leasetime to set preferred/valid statefull lifetimes

Allow to set the preferred/valid lifetimes of IA_NA/IA_PD options based
on the configured dhcp leasetime.
DHCP leqasetime will be used to set the preferred/valid lifetimes in the
IA_NA/IA_PD options unless the preferred/valid lifetimes of the IPv6
address are smaller then the DHCP leasetime.
This will avoid IA_NA/IA_PD options being sent with infinite lifetimes
due to the IPv6 address having infinite preferred/valid lifetimes
like IPv6 ULA addresses.
While at it rename dhcpv4_leasetime into dhcp_leasetime as the leasetime
is used both for DHCPv4 and DHCPv6

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

5 files changed, 17 insertions, 9 deletions

diff --git a/src/config.c b/src/config.c
index f3ba3e8..3d41e13 100644
--- a/src/config.c
+++ b/src/config.c
@@ -229,7 +229,7 @@ static void set_interface_defaults(struct interface *iface)
 	iface->ra = MODE_DISABLED;
 	iface->ndp = MODE_DISABLED;
 	iface->learn_routes = 1;
-	iface->dhcpv4_leasetime = 43200;
+	iface->dhcp_leasetime = 43200;
 	iface->dhcpv4_start.s_addr = htonl(START_DEFAULT);
 	iface->dhcpv4_end.s_addr = htonl(START_DEFAULT + LIMIT_DEFAULT - 1);
 	iface->dhcpv6_assignall = true;
@@ -547,7 +547,7 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 		if (time < 0)
 			goto err;
 
-		iface->dhcpv4_leasetime = time;
+		iface->dhcp_leasetime = time;
 	}
 
 	if ((c = tb[IFACE_ATTR_START])) {
diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 1deb097..24a4fea 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -1072,7 +1072,7 @@ dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
 			if (a->leasetime)
 				my_leasetime = a->leasetime;
 			else
-				my_leasetime = iface->dhcpv4_leasetime;
+				my_leasetime = iface->dhcp_leasetime;
 
 			if ((*leasetime == 0) || (my_leasetime < *leasetime))
 				*leasetime = my_leasetime;
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index ee0acaf..d8187ff 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -823,7 +823,7 @@ static size_t build_ia(uint8_t *buf, size_t buflen, uint16_t status,
 		if (a->leasetime)
 			leasetime = a->leasetime;
 		else
-			leasetime = iface->dhcpv4_leasetime;
+			leasetime = iface->dhcp_leasetime;
 
 		uint32_t pref = leasetime;
 		uint32_t valid = leasetime;
@@ -842,9 +842,15 @@ static size_t build_ia(uint8_t *buf, size_t buflen, uint16_t status,
 			if (prefix_pref != UINT32_MAX)
 				prefix_pref -= now;
 
+			if (prefix_pref > leasetime)
+				prefix_pref = leasetime;
+
 			if (prefix_valid != UINT32_MAX)
 				prefix_valid -= now;
 
+			if (prefix_valid > leasetime)
+				prefix_valid = leasetime;
+
 			if (a->flags & OAF_DHCPV6_PD) {
 				struct dhcpv6_ia_prefix o_ia_p = {
 					.type = htons(DHCPV6_OPT_IA_PREFIX),
diff --git a/src/odhcpd.h b/src/odhcpd.h
index ae4826e..072a148 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -272,6 +272,9 @@ struct interface {
 	uint32_t ra_hoplimit;
 	int ra_mtu;
 
+	// DHCP
+	uint32_t dhcp_leasetime;
+
 	// DHCPv4
 	struct in_addr dhcpv4_start;
 	struct in_addr dhcpv4_end;
@@ -284,7 +287,6 @@ struct interface {
 	size_t dhcpv4_router_cnt;
 	struct in_addr *dhcpv4_dns;
 	size_t dhcpv4_dns_cnt;
-	uint32_t dhcpv4_leasetime;
 	bool dhcpv4_forcereconf;
 
 	// DNS
diff --git a/src/router.c b/src/router.c
index 7c97672..295bdfb 100644
--- a/src/router.c
+++ b/src/router.c
@@ -552,13 +552,13 @@ static int send_router_advert(struct interface *iface, const struct in6_addr *fr
 			preferred = TIME_LEFT(addr->preferred, now);
 
 			if (iface->ra_useleasetime &&
-					preferred > iface->dhcpv4_leasetime)
-				preferred = iface->dhcpv4_leasetime;
+			    preferred > iface->dhcp_leasetime)
+				preferred = iface->dhcp_leasetime;
 		}
 
 		valid = TIME_LEFT(addr->valid, now);
-		if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
-			valid = iface->dhcpv4_leasetime;
+		if (iface->ra_useleasetime && valid > iface->dhcp_leasetime)
+			valid = iface->dhcp_leasetime;
 
 		if (minvalid > valid)
 			minvalid = valid;