IPv6: Remove local ULA if there is an external one

1 files changed, 39 insertions, 0 deletions

diff --git a/interface-ip.c b/interface-ip.c
index bf7cf40..d18fa74 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -476,6 +476,41 @@ interface_update_host_route(struct vlist_tree *tree,
 
 static void
 interface_set_prefix_address(struct device_prefix_assignment *assignment,
+		const struct device_prefix *prefix, struct interface *iface, bool add);
+
+static void interface_trigger_ula_prefix(struct interface *iface,
+		const struct device_prefix *prefix, bool enable)
+{
+	if (prefix == ula_prefix || (prefix->addr.s6_addr[0] & 0xfe) != 0xfc)
+		return;
+
+	bool external_ula = false;
+	struct device_prefix_assignment *ula_assign = NULL;
+	struct device_prefix *c;
+	list_for_each_entry(c, &prefixes, head) {
+		if (c != ula_prefix && (c->addr.s6_addr[0] & 0xfe) != 0xfc)
+			continue;
+
+		struct device_prefix_assignment *a;
+		list_for_each_entry(a, &c->assignments, head) {
+			if (!strcmp(a->name, iface->name)) {
+				if (c == ula_prefix)
+					ula_assign = a;
+				else if (a->enabled)
+					external_ula = true;
+			}
+		}
+
+	}
+
+	// Remove ULA assignment if there is an externally managed ULA and vice versa
+	if (ula_assign && ((enable && !external_ula) || (!enable && external_ula)))
+		interface_set_prefix_address(ula_assign, ula_prefix, iface, enable);
+}
+
+
+static void
+interface_set_prefix_address(struct device_prefix_assignment *assignment,
 		const struct device_prefix *prefix, struct interface *iface, bool add)
 {
 	const struct interface *uplink = prefix->iface;
@@ -501,6 +536,8 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
 			addr.valid_until = now + 7200;
 		system_add_address(l3_downlink, &addr);
 		assignment->enabled = false;
+
+		interface_trigger_ula_prefix(iface, prefix, true);
 	} else if (add && (iface->state == IFS_UP || iface->state == IFS_SETUP)) {
 		system_add_address(l3_downlink, &addr);
 		if (uplink && uplink->l3_dev.dev) {
@@ -510,6 +547,8 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
 				system_update_ipv6_mtu(l3_downlink, mtu);
 		}
 		assignment->enabled = true;
+
+		interface_trigger_ula_prefix(iface, prefix, false);
 	}
 }