config: Support infinite as DHCP pool leasetime value

Add support for infinite leasetime value; this can be done by
specifying "infinite" as leasetime value which is similar to
dnsmasq infinite leasetime support.
Specifying "infinite" as leasetime is valid for both the host
and dhcp uci sections.
A DHCPv4/DHCPv6 assignment is now considered infinite if valid_unil
holds the value 0.

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

1 files changed, 16 insertions, 14 deletions

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index f277a67..8469038 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -181,7 +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);
-			a->valid_until = LONG_MAX;
+			/* Infinite valid */
+			a->valid_until = 0;
 
 			// Assign to all interfaces
 			struct dhcpv4_assignment *c;
@@ -246,8 +247,7 @@ static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 	*cookie = c + len;
 }
 
-
-// Simple DHCPv6-server for information requests
+// Handler for DHCPv4 messages
 static void handle_dhcpv4(void *addr, void *data, size_t len,
 		struct interface *iface, _unused void *dest_addr)
 {
@@ -396,11 +396,13 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 		val = htonl(leasetime);
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 
-		val = htonl(500 * leasetime / 1000);
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
+		if (leasetime != UINT32_MAX) {
+			val = htonl(500 * leasetime / 1000);
+			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 
-		val = htonl(875 * leasetime / 1000);
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+			val = htonl(875 * leasetime / 1000);
+			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+		}
 
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4, &ifnetmask.sin_addr);
 
@@ -598,7 +600,7 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 			a = c;
 			if (c->addr == raddr)
 				break;
-		} else if (c->valid_until < now) {
+		} else if (!INFINITE_VALID(c->valid_until) && c->valid_until < now) {
 			list_del(&c->head);
 			free(c);
 		}
@@ -640,10 +642,10 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 			leasetime = iface->dhcpv4_leasetime;
 		}
 
-		// Was only a solicitation: mark binding for removal
+		// Was only a discover; mark binding for removal
 		if (assigned && a->valid_until < now) {
-			a->valid_until = (msg == DHCPV4_MSG_DISCOVER) ? 0 :
-					(now + leasetime);
+			a->valid_until = ((msg == DHCPV4_MSG_DISCOVER) ? now : ((leasetime == UINT32_MAX) ?
+						0 : (time_t)(now + leasetime)));
 		} else if (!assigned && a) { // Cleanup failed assignment
 			free(a);
 			a = NULL;
@@ -652,9 +654,9 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 		if (assigned && a)
 			lease = a;
 	} else if (msg == DHCPV4_MSG_RELEASE) {
-		if (a && a->valid_until != LONG_MAX)
-			a->valid_until = 0;
-	} else if (msg == DHCPV4_MSG_DECLINE && a && a->valid_until != LONG_MAX) {
+		if (a && !INFINITE_VALID(a->valid_until))
+			a->valid_until = now - 1;
+	} else if (msg == DHCPV4_MSG_DECLINE && a && !INFINITE_VALID(a->valid_until)) {
 		memset(a->hwaddr, 0, sizeof(a->hwaddr));
 		a->valid_until = now + 3600; // Block address for 1h
 	}