commit f3bd2023c3c13a5cf9400cce397607afdb9c62d5
Author: Dan Ponte <amigan@gmail.com>
Date:   Thu May 25 15:20:14 2023 -0400

    rtadvd: add deprecation of addresses on shutdown

diff --git a/usr.sbin/rtadvd/config.c b/usr.sbin/rtadvd/config.c
index f857889332a4..66c54821ae1d 100644
--- a/usr.sbin/rtadvd/config.c
+++ b/usr.sbin/rtadvd/config.c
@@ -379,6 +379,12 @@ getconfig(struct ifinfo *ifi)
 	else
 		rai->rai_advifprefix = 1;
 
+	/* deprecate on shutdown? */
+	if (agetflag("nodeprecate"))
+		rai->rai_deprecate = 0;
+	else
+		rai->rai_deprecate = 1;
+
 	/* get interface information */
 	if (agetflag("nolladdr"))
 		rai->rai_advlinkopt = 0;
diff --git a/usr.sbin/rtadvd/rtadvd.c b/usr.sbin/rtadvd/rtadvd.c
index 391c95c9bd48..acf03b6c00d8 100644
--- a/usr.sbin/rtadvd/rtadvd.c
+++ b/usr.sbin/rtadvd/rtadvd.c
@@ -369,6 +369,7 @@ rtadvd_shutdown(void)
 {
 	struct ifinfo *ifi;
 	struct rainfo *rai;
+	struct prefix *prefix;
 	struct rdnss *rdn;
 	struct dnssl *dns;
 
@@ -411,6 +412,12 @@ rtadvd_shutdown(void)
 
 	TAILQ_FOREACH(rai, &railist, rai_next) {
 		rai->rai_lifetime = 0;
+		if (rai->rai_deprecate) {
+			TAILQ_FOREACH(prefix, &rai->rai_prefix, pfx_next) {
+				prefix->pfx_validlifetime = 0;
+				prefix->pfx_preflifetime = 0;
+			}
+		}
 		TAILQ_FOREACH(rdn, &rai->rai_rdnss, rd_next)
 			rdn->rd_ltime = 0;
 		TAILQ_FOREACH(dns, &rai->rai_dnssl, dn_next)
diff --git a/usr.sbin/rtadvd/rtadvd.conf.5 b/usr.sbin/rtadvd/rtadvd.conf.5
index d4a0c0258915..ade8f13829bd 100644
--- a/usr.sbin/rtadvd/rtadvd.conf.5
+++ b/usr.sbin/rtadvd/rtadvd.conf.5
@@ -430,6 +430,19 @@ DNS search list entries.
 The default value is 3/2 of the interval time.
 .El
 .Pp
+The following item controls prefix deprecation on
+.Nm rtadvd
+shutdown.
+.Bl -tag -width indent
+.It Cm \&nodeprecate
+(bool) By default
+.Pc ,
+.Xr rtadvd 8
+will deprecate prefixes on shutdown. If this capability exists,
+.Xr rtadvd 8
+will not deprecate addresses on shutdown.
+.El
+.Pp
 You can also refer one line from another by using
 .Cm tc
 capability.
diff --git a/usr.sbin/rtadvd/rtadvd.h b/usr.sbin/rtadvd/rtadvd.h
index 885d2fbb3c80..68d9748d0ee1 100644
--- a/usr.sbin/rtadvd/rtadvd.h
+++ b/usr.sbin/rtadvd/rtadvd.h
@@ -189,6 +189,7 @@ struct	rainfo {
 
 	int	rai_advlinkopt;		/* bool: whether include link-layer addr opt */
 	int	rai_advifprefix;	/* bool: gather IF prefixes? */
+	int	rai_deprecate;		/* bool: deprecate on shutdown */
 
 	/* Router configuration variables */
 	uint16_t	rai_lifetime;		/* AdvDefaultLifetime */