Author: markj
Date: Sat Mar 30 18:00:44 2019
New Revision: 345739
URL: https://svnweb.freebsd.org/changeset/base/345739
Log:
Do not perform DAD on stf(4) interfaces.
stf(4) interfaces are not multicast-capable so they can't perform DAD.
They also did not set IFF_DRV_RUNNING when an address was assigned, so
the logic in nd6_timer() would periodically flag such an address as
tentative, resulting in interface flapping.
Fix the problem by setting IFF_DRV_RUNNING when an address is assigned,
and do some related cleanup:
- In in6if_do_dad(), remove a redundant check for !UP || !RUNNING.
There is only one caller in the tree, and it only looks at whether
the return value is non-zero.
- Have in6if_do_dad() return false if the interface is not
multicast-capable.
- Set ND6_IFF_NO_DAD when an address is assigned to an stf(4) interface
and the interface goes UP as a result. Note that this is not
sufficient to fix the problem because the new address is marked as
tentative and DAD is started before in6_ifattach() is called.
However, setting no_dad is formally correct.
- Change nd6_timer() to not flag addresses as tentative if no_dad is
set.
This is based on a patch from Viktor Dukhovni.
Reported by: Viktor Dukhovni <ietf-d...@dukhovni.org>
Reviewed by: ae
MFC after: 3 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19751
Modified:
head/sys/net/if_stf.c
head/sys/netinet6/in6.c
head/sys/netinet6/in6_ifattach.c
head/sys/netinet6/nd6.c
Modified: head/sys/net/if_stf.c
==============================================================================
--- head/sys/net/if_stf.c Sat Mar 30 17:42:27 2019 (r345738)
+++ head/sys/net/if_stf.c Sat Mar 30 18:00:44 2019 (r345739)
@@ -724,6 +724,7 @@ stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
}
ifp->if_flags |= IFF_UP;
+ ifp->if_drv_flags |= IFF_DRV_RUNNING;
break;
case SIOCADDMULTI:
Modified: head/sys/netinet6/in6.c
==============================================================================
--- head/sys/netinet6/in6.c Sat Mar 30 17:42:27 2019 (r345738)
+++ head/sys/netinet6/in6.c Sat Mar 30 18:00:44 2019 (r345739)
@@ -1951,26 +1951,14 @@ in6_if_up(struct ifnet *ifp)
int
in6if_do_dad(struct ifnet *ifp)
{
+
if ((ifp->if_flags & IFF_LOOPBACK) != 0)
return (0);
-
- if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) ||
- (ND_IFINFO(ifp)->flags & ND6_IFF_NO_DAD))
+ if ((ifp->if_flags & IFF_MULTICAST) == 0)
return (0);
-
- /*
- * Our DAD routine requires the interface up and running.
- * However, some interfaces can be up before the RUNNING
- * status. Additionally, users may try to assign addresses
- * before the interface becomes up (or running).
- * This function returns EAGAIN in that case.
- * The caller should mark "tentative" on the address instead of
- * performing DAD immediately.
- */
- if (!((ifp->if_flags & IFF_UP) &&
- (ifp->if_drv_flags & IFF_DRV_RUNNING)))
- return (EAGAIN);
-
+ if ((ND_IFINFO(ifp)->flags &
+ (ND6_IFF_IFDISABLED | ND6_IFF_NO_DAD)) != 0)
+ return (0);
return (1);
}
Modified: head/sys/netinet6/in6_ifattach.c
==============================================================================
--- head/sys/netinet6/in6_ifattach.c Sat Mar 30 17:42:27 2019
(r345738)
+++ head/sys/netinet6/in6_ifattach.c Sat Mar 30 18:00:44 2019
(r345739)
@@ -692,6 +692,7 @@ in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
* it is rather harmful to have one.
*/
ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
+ ND_IFINFO(ifp)->flags |= ND6_IFF_NO_DAD;
break;
default:
break;
Modified: head/sys/netinet6/nd6.c
==============================================================================
--- head/sys/netinet6/nd6.c Sat Mar 30 17:42:27 2019 (r345738)
+++ head/sys/netinet6/nd6.c Sat Mar 30 18:00:44 2019 (r345739)
@@ -900,6 +900,7 @@ nd6_timer(void *arg)
struct nd_prhead prl;
struct nd_defrouter *dr, *ndr;
struct nd_prefix *pr, *npr;
+ struct ifnet *ifp;
struct in6_ifaddr *ia6, *nia6;
uint64_t genid;
@@ -996,14 +997,15 @@ nd6_timer(void *arg)
* Check status of the interface. If it is down,
* mark the address as tentative for future DAD.
*/
- if ((ia6->ia_ifp->if_flags & IFF_UP) == 0 ||
- (ia6->ia_ifp->if_drv_flags & IFF_DRV_RUNNING)
- == 0 ||
- (ND_IFINFO(ia6->ia_ifp)->flags &
- ND6_IFF_IFDISABLED) != 0) {
+ ifp = ia6->ia_ifp;
+ if ((ND_IFINFO(ifp)->flags & ND6_IFF_NO_DAD) == 0 &&
+ ((ifp->if_flags & IFF_UP) == 0 ||
+ (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
+ (ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) != 0)){
ia6->ia6_flags &= ~IN6_IFF_DUPLICATED;
ia6->ia6_flags |= IN6_IFF_TENTATIVE;
}
+
/*
* A new RA might have made a deprecated address
* preferred.
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