Limit lifetime of non-static leases in case of release and decline

In case infinite leasetime is assigned to a non static DHCPv4/v6 lease
override the infinite lifetime of the lease when either a DHCPv4/v6
decline or release is received.

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

3 files changed, 18 insertions, 13 deletions

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 7695d68..509b092 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -181,6 +181,8 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
 			a->addr = ntohl(lease->ipaddr.s_addr);
 			memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
 			memcpy(a->hostname, lease->hostname, hostlen);
+			/* Static assignment */
+			a->flags |= OAF_STATIC;
 			/* Infinite valid */
 			a->valid_until = 0;
 
@@ -643,17 +645,17 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 			*leasetime = my_leasetime;
 
 		if (assigned) {
-			bool is_discover = (msg == DHCPV4_MSG_DISCOVER);
+			if (msg == DHCPV4_MSG_DISCOVER) {
+				a->flags &= ~OAF_BOUND;
 
-			if (!INFINITE_VALID(a->valid_until))
-				// Was only a discover; mark binding for removal
-				a->valid_until = (is_discover ? now : ((*leasetime == UINT32_MAX) ?
-							0 : (time_t)(now + *leasetime)));
-
-			/* Mark assignment as bound */
-			if (!is_discover)
+				if (!(a->flags & OAF_STATIC))
+					a->valid_until = now;
+			} else {
 				a->flags |= OAF_BOUND;
 
+				if (!(a->flags & OAF_STATIC))
+					a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
+			}
 		} else if (!assigned && a) { // Cleanup failed assignment
 			free(a);
 			a = NULL;
@@ -664,13 +666,13 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 	} else if (msg == DHCPV4_MSG_RELEASE && a) {
 		a->flags &= ~OAF_BOUND;
 
-		if (!INFINITE_VALID(a->valid_until))
+		if (!(a->flags & OAF_STATIC))
 			a->valid_until = now - 1;
 
 	} else if (msg == DHCPV4_MSG_DECLINE && a) {
 		a->flags &= ~OAF_BOUND;
 
-		if (!INFINITE_VALID(a->valid_until)) {
+		if (!(a->flags & OAF_STATIC)) {
 			memset(a->hwaddr, 0, sizeof(a->hwaddr));
 			a->valid_until = now + 3600; // Block address for 1h
 		}
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index e8b6e9f..a7146a7 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -114,6 +114,8 @@ int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
 			odhcpd_urandom(a->key, sizeof(a->key));
 			memcpy(a->clid_data, lease->duid, lease->duid_len);
 			memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
+			/* Static assignment */
+			a->flags |= OAF_STATIC;
 			/* Infinite valid */
 			a->valid_until = 0;
 
@@ -1130,7 +1132,7 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 			if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 				a->flags &= ~OAF_BOUND;
 
-				if (!INFINITE_VALID(a->valid_until))
+				if (!(a->flags & OAF_STATIC))
 					a->valid_until = now;
 			} else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 				if (hostname_len > 0) {
@@ -1161,7 +1163,7 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 					apply_lease(iface, a, true);
 				}
 			} else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
-				if (!INFINITE_VALID(a->valid_until))
+				if (!(a->flags & OAF_STATIC))
 					a->valid_until = now - 1;
 
 				a->flags &= ~OAF_BOUND;
@@ -1169,7 +1171,7 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 			} else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
 				a->flags &= ~OAF_BOUND;
 
-				if (!INFINITE_VALID(a->valid_until)) {
+				if (!(a->flags & OAF_STATIC)) {
 					a->clid_len = 0;
 					a->valid_until = now + 3600; // Block address for 1h
 				}
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 4b77313..0e5868c 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -86,6 +86,7 @@ enum odhcpd_mode {
 
 enum odhcpd_assignment_flags {
 	OAF_BOUND	= (1 << 0),
+	OAF_STATIC	= (1 << 1),
 };
 
 struct config {