From: claudio <claudio@openbsd.org>
Date: Mon, 14 Nov 2022 17:12:55 +0000 (+0000)
Subject: Relax the list of interfaces which support IPv6 a bit.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=345c4d05797bdbbc2347b7d2c731f27795fbf9b1;p=openbsd

Relax the list of interfaces which support IPv6 a bit.

No longer require IFF_MULTICAST for all interfaces. It is save to skip
this for interfaces that don't require a ND cache. Also do not assign a
link-local address in such cases. This affects point-to-point interfaces
and the NBMA / point-to-multipoint interfaces like mpe(4), mgre(4) and wg(4).
The NBMA interfaces need some alternative way to figure out the address
mapping. In the end this allows non-multicast interfaces to work with IPv6.
OK dlg@ kn@
---

diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 09a9878fce6..7550297f88e 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_ifattach.c,v 1.119 2022/09/08 10:22:07 kn Exp $	*/
+/*	$OpenBSD: in6_ifattach.c,v 1.120 2022/11/14 17:12:55 claudio Exp $	*/
 /*	$KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei Exp $	*/
 
 /*
@@ -373,7 +373,7 @@ in6_ifattach(struct ifnet *ifp)
 	if (ifp->if_mtu < IPV6_MMTU)
 		return (EINVAL);
 
-	if ((ifp->if_flags & IFF_MULTICAST) == 0)
+	if (nd6_need_cache(ifp) && (ifp->if_flags & IFF_MULTICAST) == 0)
 		return (EINVAL);
 
 	/*
@@ -389,12 +389,12 @@ in6_ifattach(struct ifnet *ifp)
 			return (error);
 	}
 
-	/* Interfaces that rely on strong a priori cryptographic binding of
-	 * IP addresses are incompatible with automatically assigned llv6. */
-	switch (ifp->if_type) {
-	case IFT_WIREGUARD:
+	/*
+	 * Only interfaces that need the ND cache should automatically
+	 * assign a link local address.
+	 */
+	if (!nd6_need_cache(ifp))
 		return (0);
-	}
 
 	/* Assign a link-local address, if there's none. */
 	if (in6ifa_ifpforlinklocal(ifp, 0) == NULL) {