From 43abdd5301c1b1c40fa9d082267a2c2fd7a6f9fa Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Mon, 28 Nov 2022 19:13:36 +0000
Subject: [PATCH] Document struct nd_ifinfo protection, remove obsolete
 .initialized member

All access to struct ifnet's member *if_nd is read-only, with the one
write exception being nd6_slowtimo() updating ND information.

IPv6 Neighbour Discovery information is fully protected by the net lock.
---
nd6_ifattach() allocates and unconditionally initialises struct ifnet's
*if_nd member, so early in if_attachsetup() that there is no way to query
unitialised Neighour Unreachable Detection bits.

Only SIOCGIFINFO_IN6 through ndp(8) used the .initialized member:
Added/set since 2002 sys/netinet6/nd6.c r1.42
    attach nd_ifinfo structure to if_afdata.
    split IPv6 MTU (advertised by RA) from real link MTU.
    sync with kame

Read      since 2002 usr.sbin/ndp/ndp.c r1.16
    use new SIOCGIFINFO_IN6.  random other cleanups.  sync w/kame.

Obsolete  since 2017 sys/netinet6/nd6.c r1.217
                     usr.sbin/ndp/ndp.c r1.85
    Remove knob and always do neighbor unreachable detection.

Feedback OK bluhm
---
 sys/netinet6/nd6.c |  4 +---
 sys/netinet6/nd6.h | 17 +++++++++++------
 usr.sbin/ndp/ndp.c |  5 +----
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 18b590aa738..8cedafd1d35 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.c,v 1.255 2022/11/28 13:10:58 kn Exp $	*/
+/*	$OpenBSD: nd6.c,v 1.256 2022/11/28 19:13:36 kn Exp $	*/
 /*	$KAME: nd6.c,v 1.280 2002/06/08 19:52:07 itojun Exp $	*/
 
 /*
@@ -124,8 +124,6 @@ nd6_ifattach(struct ifnet *ifp)
 
 	nd = malloc(sizeof(*nd), M_IP6NDP, M_WAITOK | M_ZERO);
 
-	nd->initialized = 1;
-
 	nd->basereachable = REACHABLE_TIME;
 	nd->reachable = ND_COMPUTE_RTIME(nd->basereachable);
 	nd->retrans = RETRANS_TIMER;
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index d4568b9b979..6f29de0fe72 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.h,v 1.89 2022/11/23 19:35:42 kn Exp $	*/
+/*	$OpenBSD: nd6.h,v 1.90 2022/11/28 19:13:36 kn Exp $	*/
 /*	$KAME: nd6.h,v 1.95 2002/06/08 11:31:06 itojun Exp $	*/
 
 /*
@@ -43,12 +43,17 @@
 #define ND6_LLINFO_DELAY	3
 #define ND6_LLINFO_PROBE	4
 
+/*
+ *  Locks used to protect struct members in this file:
+ *	I	immutable after creation
+ *	N	net lock
+ */
+
 struct nd_ifinfo {
-	u_int32_t basereachable;	/* BaseReachableTime */
-	u_int32_t reachable;		/* Reachable Time */
-	u_int32_t retrans;		/* Retrans Timer */
-	int recalctm;			/* BaseReacable re-calculation timer */
-	u_int8_t initialized; /* Flag to see the entry is initialized */
+	u_int32_t basereachable;	/* [I] BaseReachableTime */
+	u_int32_t reachable;		/* [N] Reachable Time */
+	u_int32_t retrans;		/* [I] Retrans Timer */
+	int recalctm;			/* [N] BaseReachable recalc timer */
 };
 
 struct in6_nbrinfo {
diff --git a/usr.sbin/ndp/ndp.c b/usr.sbin/ndp/ndp.c
index 8b3cfeeb300..80cca743bc4 100644
--- a/usr.sbin/ndp/ndp.c
+++ b/usr.sbin/ndp/ndp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ndp.c,v 1.104 2022/11/09 18:00:02 kn Exp $	*/
+/*	$OpenBSD: ndp.c,v 1.105 2022/11/28 19:13:36 kn Exp $	*/
 /*	$KAME: ndp.c,v 1.101 2002/07/17 08:46:33 itojun Exp $	*/
 
 /*
@@ -888,9 +888,6 @@ ifinfo(const char *ifname)
 	if (ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&nd) == -1)
 		err(1, "ioctl(SIOCGIFINFO_IN6)");
 
-	if (!nd.ndi.initialized)
-		errx(1, "%s: not initialized yet", ifname);
-
 	printf("basereachable=%ds%dms",
 	    nd.ndi.basereachable / 1000, nd.ndi.basereachable % 1000);
 	printf(", reachable=%ds", nd.ndi.reachable);
-- 
2.20.1