From 1b840e0c23aaf1f0c1b80747e163cc6da174014b Mon Sep 17 00:00:00 2001
From: Jon Franklin <jon_franklin@dell.com>
Date: Wed, 12 Feb 2025 12:46:50 +0000
Subject: [PATCH] DHCP6: Implement USE_MULTICAST

---
 src/dhcp6.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/dhcp6.c b/src/dhcp6.c
index fad22f73..fb4d9361 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -2202,6 +2202,12 @@ dhcp6_checkstatusok(const struct interface *ifp,
 	state->lerror = code;
 	errno = 0;
 
+	/* RFC 8415 18.2.10 */
+	if (code == D6_STATUS_USEMULTICAST) {
+		logdebugx("%s: server sent USEMULTICAST", ifp->name);
+		state->unicast = in6addr_any;
+	}
+
 	/* code cannot be D6_STATUS_OK, so there is a failure */
 	if (ifp->ctx->options & DHCPCD_TEST)
 		eloop_exit(ifp->ctx->eloop, EXIT_FAILURE);
-- 
2.47.2