in6: Add a helper function to compute expiry times

Tidy up a bunch of places that have the same duplicated logic.  Simplify
callers of in6_init_prefix_ltimes().  No functional change intended.

Reviewed by:	pouria, zlei, tuexen, glebius
MFC after:	2 weeks
Sponsored by:	OPNsense
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D54561

sys/netinet6/in6.c

@@ -1029,6 +1029,15 @@ in6_alloc_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra, int flags)
 	return (ia);
 }
 
+time_t
+in6_expire_time(uint32_t ltime)
+{
+	if (ltime == ND6_INFINITE_LIFETIME)
+		return (0);
+	else
+		return (time_uptime + ltime);
+}
+
 /*
  * Update/configure interface address parameters:
  *
@@ -1051,16 +1060,10 @@ in6_update_ifa_internal(struct ifnet *ifp, struct in6_aliasreq *ifra,
 	 * these members for applications.
 	 */
 	ia->ia6_lifetime = ifra->ifra_lifetime;
-	if (ia->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME) {
-		ia->ia6_lifetime.ia6t_expire =
-		    time_uptime + ia->ia6_lifetime.ia6t_vltime;
-	} else
-		ia->ia6_lifetime.ia6t_expire = 0;
-	if (ia->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME) {
-		ia->ia6_lifetime.ia6t_preferred =
-		    time_uptime + ia->ia6_lifetime.ia6t_pltime;
-	} else
-		ia->ia6_lifetime.ia6t_preferred = 0;
+	ia->ia6_lifetime.ia6t_expire =
+	    in6_expire_time(ifra->ifra_lifetime.ia6t_vltime);
+	ia->ia6_lifetime.ia6t_preferred =
+	    in6_expire_time(ifra->ifra_lifetime.ia6t_pltime);
 
 	/*
 	 * backward compatibility - if IN6_IFF_DEPRECATED is set from the

sys/netinet6/in6.h

@@ -671,6 +671,8 @@ int	in6_cksum_partial_l2(struct mbuf *m, uint8_t nxt, uint32_t off_l3,
 	    uint32_t off_l4, uint32_t len, uint32_t cov);
 int	in6_cksum_pseudo(struct ip6_hdr *, uint32_t, uint8_t, uint16_t);
 
+time_t	in6_expire_time(uint32_t);
+
 int	in6_localaddr(struct in6_addr *);
 int	in6_localip(struct in6_addr *);
 bool	in6_localip_fib(struct in6_addr *, uint16_t);

sys/netinet6/nd6_rtr.c

@@ -1146,39 +1146,18 @@ defrtrlist_update(struct nd_defrouter *new)
 	return (n);
 }
 
-static int
+static void
 in6_init_prefix_ltimes(struct nd_prefix *ndpr)
 {
-	if (ndpr->ndpr_pltime == ND6_INFINITE_LIFETIME)
-		ndpr->ndpr_preferred = 0;
-	else
-		ndpr->ndpr_preferred = time_uptime + ndpr->ndpr_pltime;
-	if (ndpr->ndpr_vltime == ND6_INFINITE_LIFETIME)
-		ndpr->ndpr_expire = 0;
-	else
-		ndpr->ndpr_expire = time_uptime + ndpr->ndpr_vltime;
-
-	return 0;
+	ndpr->ndpr_preferred = in6_expire_time(ndpr->ndpr_pltime);
+	ndpr->ndpr_expire = in6_expire_time(ndpr->ndpr_vltime);
 }
 
 static void
 in6_init_address_ltimes(struct nd_prefix *new, struct in6_addrlifetime *lt6)
 {
-	/* init ia6t_expire */
-	if (lt6->ia6t_vltime == ND6_INFINITE_LIFETIME)
-		lt6->ia6t_expire = 0;
-	else {
-		lt6->ia6t_expire = time_uptime;
-		lt6->ia6t_expire += lt6->ia6t_vltime;
-	}
-
-	/* init ia6t_preferred */
-	if (lt6->ia6t_pltime == ND6_INFINITE_LIFETIME)
-		lt6->ia6t_preferred = 0;
-	else {
-		lt6->ia6t_preferred = time_uptime;
-		lt6->ia6t_preferred += lt6->ia6t_pltime;
-	}
+	lt6->ia6t_preferred = in6_expire_time(lt6->ia6t_pltime);
+	lt6->ia6t_expire = in6_expire_time(lt6->ia6t_vltime);
 }
 
 static struct in6_ifaddr *
@@ -1394,11 +1373,8 @@ nd6_prelist_add(struct nd_prefixctl *pr, struct nd_defrouter *dr,
 	new->ndpr_vltime = pr->ndpr_vltime;
 	new->ndpr_pltime = pr->ndpr_pltime;
 	new->ndpr_flags = pr->ndpr_flags;
-	if ((error = in6_init_prefix_ltimes(new)) != 0) {
-		free(new, M_IP6NDP);
-		return (error);
-	}
 	new->ndpr_lastupdate = time_uptime;
+	in6_init_prefix_ltimes(new);
 
 	/* initialization */
 	LIST_INIT(&new->ndpr_advrtrs);
@@ -1542,7 +1518,7 @@ prelist_update(struct nd_prefixctl *new, struct nd_defrouter *dr,
 		if (new->ndpr_raf_onlink) {
 			pr->ndpr_vltime = new->ndpr_vltime;
 			pr->ndpr_pltime = new->ndpr_pltime;
-			(void)in6_init_prefix_ltimes(pr); /* XXX error case? */
+			in6_init_prefix_ltimes(pr);
 			pr->ndpr_lastupdate = time_uptime;
 		}