svn commit: r368031 - in head: libexec/rc sys/netinet6

[Bjoern A. Zeeb]

Author: bz
Date: Wed Nov 25 20:58:01 2020
New Revision: 368031
URL: https://svnweb.freebsd.org/changeset/base/368031

Log:
  IPv6: set ifdisabled in the kernel rather than in rc
  
  Enable ND6_IFF_IFDISABLED when the interface is created in the
  kernel before return to user space.
  
  This avoids a race when an interface is create by a program which
  also calls ifconfig IF inet6 -ifdisabled and races with the
  devd -> /etc/pccard_ether -> .. netif start IF -> ifdisabled
  calls (the devd/rc framework disabling IPv6 again after the program
  had enabled it already).
  
  In case the global net.inet6.ip6.accept_rtadv was turned on,
  we also default to enabling IPv6 on the interfaces, rather than
  disabling them.
  
  PR:		248172
  Reported by:	Gert Doering (gert greenie.muc.de)
  Reviewed by:	glebius (, phk)
  MFC after:	2 weeks
  Differential Revision:	https://reviews.freebsd.org/D27324

Modified:
  head/libexec/rc/network.subr
  head/sys/netinet6/nd6.c

Modified: head/libexec/rc/network.subr
==============================================================================
--- head/libexec/rc/network.subr	Wed Nov 25 20:05:05 2020	(r368030)
+++ head/libexec/rc/network.subr	Wed Nov 25 20:58:01 2020	(r368031)
@@ -134,8 +134,6 @@ ifconfig_up()
 	if ! noafif $1 && afexists inet6; then
 		if checkyesno ipv6_activate_all_interfaces; then
 			_ipv6_opts="-ifdisabled"
-		elif [ "$1" != "lo0" ]; then
-			_ipv6_opts="ifdisabled"
 		fi
 
 		# backward compatibility: $ipv6_enable

Modified: head/sys/netinet6/nd6.c
==============================================================================
--- head/sys/netinet6/nd6.c	Wed Nov 25 20:05:05 2020	(r368030)
+++ head/sys/netinet6/nd6.c	Wed Nov 25 20:58:01 2020	(r368031)
@@ -273,6 +273,10 @@ nd6_ifattach(struct ifnet *ifp)
 
 	nd->flags = ND6_IFF_PERFORMNUD;
 
+	/* Set IPv6 disabled on all interfaces but loopback by default. */
+	if ((ifp->if_flags & IFF_LOOPBACK) == 0)
+		nd->flags |= ND6_IFF_IFDISABLED;
+
 	/* A loopback interface always has ND6_IFF_AUTO_LINKLOCAL.
 	 * XXXHRS: Clear ND6_IFF_AUTO_LINKLOCAL on an IFT_BRIDGE interface by
 	 * default regardless of the V_ip6_auto_linklocal configuration to
@@ -290,8 +294,11 @@ nd6_ifattach(struct ifnet *ifp)
 	 */
 	if (V_ip6_accept_rtadv &&
 	    !(ifp->if_flags & IFF_LOOPBACK) &&
-	    (ifp->if_type != IFT_BRIDGE))
+	    (ifp->if_type != IFT_BRIDGE)) {
 			nd->flags |= ND6_IFF_ACCEPT_RTADV;
+			/* If we globally accept rtadv, assume IPv6 on. */
+			nd->flags &= ~ND6_IFF_IFDISABLED;
+	}
 	if (V_ip6_no_radr && !(ifp->if_flags & IFF_LOOPBACK))
 		nd->flags |= ND6_IFF_NO_RADR;