From ac40cb1679d5bdab31c9a4eb014fe9a6985092db Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Wed, 23 Nov 2022 14:48:27 +0000
Subject: [PATCH] Add *if_nd to struct ifnet, call nd6_if{at,de}tach() directly

*if_afdata[] and struct domain's dom_if{at,de}tach() are only used with
IPv6 Neighbour Discovery in6_dom{at,de}tach(), which allocate/init and
free single struct nd_ifinfo.

Set up a new ND-specific *if_nd member directly to avoid yet another
layer of indirection and thus make the generic domain API obsolete.

The per-interface data is only accessed in nd6.c and nd6_nbr.c through
the ND_IFINFO() macro;  it is allocated and freed exactly once during
interface at/detach, so document it as [I]mmutable.

OK bluhm mvs claudio
---
 sys/net/if.c             |  9 ++++++++-
 sys/net/if_var.h         |  3 ++-
 sys/netinet6/in6.c       | 14 +-------------
 sys/netinet6/in6_proto.c |  4 +---
 sys/netinet6/nd6.h       |  4 ++--
 5 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index f3fba33de3f..36ac89ceb46 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.680 2022/11/14 22:45:02 kn Exp $	*/
+/*	$OpenBSD: if.c,v 1.681 2022/11/23 14:48:27 kn Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -461,6 +461,10 @@ if_attachsetup(struct ifnet *ifp)
 	if_addgroup(ifp, IFG_ALL);
 
 	if_attachdomain(ifp);
+#ifdef INET6
+	ifp->if_nd = nd6_ifattach(ifp);
+#endif
+
 #if NPF > 0
 	pfi_attach_ifnet(ifp);
 #endif
@@ -1127,6 +1131,9 @@ if_detach(struct ifnet *ifp)
 			(*dp->dom_ifdetach)(ifp,
 			    ifp->if_afdata[dp->dom_family]);
 	}
+#ifdef INET6
+	nd6_ifdetach(ifp->if_nd);
+#endif
 
 	/* Announce that the interface is gone. */
 	rtm_ifannounce(ifp, IFAN_DEPARTURE);
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 3a418bf0547..eeb2aa8ba4a 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_var.h,v 1.120 2022/11/14 22:06:26 kn Exp $	*/
+/*	$OpenBSD: if_var.h,v 1.121 2022/11/23 14:48:27 kn Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -187,6 +187,7 @@ struct ifnet {				/* and the entries */
 	struct sockaddr_dl *if_sadl;	/* [N] pointer to our sockaddr_dl */
 
 	void	*if_afdata[AF_MAX];
+	struct	nd_ifinfo *if_nd;	/* [I] IPv6 Neighour Discovery info */
 };
 #define	if_mtu		if_data.ifi_mtu
 #define	if_type		if_data.ifi_type
diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 0c45b3048bc..44dfa3488ef 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6.c,v 1.255 2022/11/23 07:57:39 kn Exp $	*/
+/*	$OpenBSD: in6.c,v 1.256 2022/11/23 14:48:28 kn Exp $	*/
 /*	$KAME: in6.c,v 1.372 2004/06/14 08:14:21 itojun Exp $	*/
 
 /*
@@ -1597,15 +1597,3 @@ in6if_do_dad(struct ifnet *ifp)
 		return (1);
 	}
 }
-
-void *
-in6_domifattach(struct ifnet *ifp)
-{
-	return nd6_ifattach(ifp);
-}
-
-void
-in6_domifdetach(struct ifnet *ifp, void *aux)
-{
-	nd6_ifdetach(aux);
-}
diff --git a/sys/netinet6/in6_proto.c b/sys/netinet6/in6_proto.c
index 808422f6eab..4e48a1e45b5 100644
--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_proto.c,v 1.111 2022/09/02 13:12:32 mvs Exp $	*/
+/*	$OpenBSD: in6_proto.c,v 1.112 2022/11/23 14:48:28 kn Exp $	*/
 /*	$KAME: in6_proto.c,v 1.66 2000/10/10 15:35:47 itojun Exp $	*/
 
 /*
@@ -338,8 +338,6 @@ const struct domain inet6domain = {
   .dom_sasize = sizeof(struct sockaddr_in6),
   .dom_rtoffset = offsetof(struct sockaddr_in6, sin6_addr),
   .dom_maxplen = 128,
-  .dom_ifattach = in6_domifattach,
-  .dom_ifdetach = in6_domifdetach
 };
 
 /*
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index e43e9b721f1..39c2fb384c0 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nd6.h,v 1.83 2022/11/23 07:57:39 kn Exp $	*/
+/*	$OpenBSD: nd6.h,v 1.84 2022/11/23 14:48:28 kn Exp $	*/
 /*	$KAME: nd6.h,v 1.95 2002/06/08 11:31:06 itojun Exp $	*/
 
 /*
@@ -94,7 +94,7 @@ struct	in6_ndifreq {
 #include <sys/queue.h>
 
 #define ND_IFINFO(ifp) \
-	((struct nd_ifinfo *)(ifp)->if_afdata[AF_INET6])
+	((ifp)->if_nd)
 
 struct	llinfo_nd6 {
 	TAILQ_ENTRY(llinfo_nd6)	ln_list;
-- 
2.20.1