Let nd6_if{at,de}tach() be void and take an ifp argument

[Klemens Nanni]

Do it like the rest of at/detach routines which modify a struct ifnet
pointer without returning anything.

OK?

diff --git a/sys/net/if.c b/sys/net/if.c
index c30d7e30e4f..3cb8bbf9176 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -460,7 +460,7 @@ if_attachsetup(struct ifnet *ifp)
        if_addgroup(ifp, IFG_ALL);
 
 #ifdef INET6
-       ifp->if_nd = nd6_ifattach(ifp);
+       nd6_ifattach(ifp);
 #endif
 
 #if NPF > 0
@@ -1105,7 +1105,7 @@ if_detach(struct ifnet *ifp)
        KASSERT(TAILQ_EMPTY(&ifp->if_detachhooks));
 
 #ifdef INET6
-       nd6_ifdetach(ifp->if_nd);
+       nd6_ifdetach(ifp);
 #endif
 
        /* Announce that the interface is gone. */
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 97c3536be9d..1924c36c813 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -126,7 +126,7 @@ nd6_init(void)
        timeout_set(&nd6_expire_timeout, nd6_expire_timer, NULL);
 }
 
-struct nd_ifinfo *
+void
 nd6_ifattach(struct ifnet *ifp)
 {
        struct nd_ifinfo *nd;
@@ -139,12 +139,13 @@ nd6_ifattach(struct ifnet *ifp)
        nd->reachable = ND_COMPUTE_RTIME(nd->basereachable);
        nd->retrans = RETRANS_TIMER;
 
-       return nd;
+       ifp->if_nd = nd;
 }
 
 void
-nd6_ifdetach(struct nd_ifinfo *nd)
+nd6_ifdetach(struct ifnet *ifp)
 {
+       struct nd_ifinfo *nd = ifp->if_nd;
 
        free(nd, M_IP6NDP, sizeof(*nd));
 }
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index 9adb0c700f6..53913e67bab 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -135,8 +135,8 @@ union nd_opts {
 #define nd_opts_done           nd_opt_each.done
 
 void nd6_init(void);
-struct nd_ifinfo *nd6_ifattach(struct ifnet *);
-void nd6_ifdetach(struct nd_ifinfo *);
+void nd6_ifattach(struct ifnet *);
+void nd6_ifdetach(struct ifnet *);
 int nd6_is_addr_neighbor(const struct sockaddr_in6 *, struct ifnet *);
 void nd6_option_init(void *, int, union nd_opts *);
 struct nd_opt_hdr *nd6_option(union nd_opts *);