Revert previous, it breaks IPv6 on loopback interfaces.

Reported by bket & anton

diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 244fb26..50bceb0 100644 (file)
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: in6.c,v 1.263 2024/04/16 14:37:49 florian Exp $       */
+/*     $OpenBSD: in6.c,v 1.264 2024/04/17 08:36:30 florian Exp $       */
 /*     $KAME: in6.c,v 1.372 2004/06/14 08:14:21 itojun Exp $   */
 
 /*
@@ -565,7 +565,7 @@ in6_update_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra,
         * The destination address for a p2p link must have a family
         * of AF_UNSPEC or AF_INET6.
         */
-       if ((ifp->if_flags & IFF_POINTOPOINT) &&
+       if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
            ifra->ifra_dstaddr.sin6_family != AF_INET6 &&
            ifra->ifra_dstaddr.sin6_family != AF_UNSPEC)
                return (EAFNOSUPPORT);
@@ -603,18 +603,19 @@ in6_update_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra,
         * zone identifier.
         */
        dst6 = ifra->ifra_dstaddr;
-       if ((ifp->if_flags & IFF_POINTOPOINT) &&
+       if ((ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)) != 0 &&
            (dst6.sin6_family == AF_INET6)) {
                error = in6_check_embed_scope(&dst6, ifp->if_index);
                if (error)
                        return error;
        }
        /*
-        * The destination address can be specified only for a p2p interface.
-        * If specified, the corresponding prefix length must be 128.
+        * The destination address can be specified only for a p2p or a
+        * loopback interface.  If specified, the corresponding prefix length
+        * must be 128.
         */
        if (ifra->ifra_dstaddr.sin6_family == AF_INET6) {
-               if (!(ifp->if_flags & IFF_POINTOPOINT))
+               if ((ifp->if_flags & (IFF_POINTOPOINT|IFF_LOOPBACK)) == 0)
                        return (EINVAL);
                if (plen != 128)
                        return (EINVAL);
@@ -651,7 +652,7 @@ in6_update_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra,
                ia6->ia_addr.sin6_family = AF_INET6;
                ia6->ia_addr.sin6_len = sizeof(ia6->ia_addr);
                ia6->ia6_updatetime = getuptime();
-               if (ifp->if_flags & IFF_POINTOPOINT) {
+               if ((ifp->if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK)) != 0) {
                        /*
                         * XXX: some functions expect that ifa_dstaddr is not
                         * NULL for p2p interfaces.
@@ -686,7 +687,7 @@ in6_update_ifa(struct ifnet *ifp, struct in6_aliasreq *ifra,
        /*
         * If a new destination address is specified, scrub the old one and
         * install the new destination.  Note that the interface must be
-        * p2p (see the check above.)
+        * p2p or loopback (see the check above.)
         */
        if ((ifp->if_flags & IFF_POINTOPOINT) && dst6.sin6_family == AF_INET6 &&
            !IN6_ARE_ADDR_EQUAL(&dst6.sin6_addr, &ia6->ia_dstaddr.sin6_addr)) {