This commit does two things:

1. rt_check() cleanup:
    rt_check() is only necessary for some address families to gain access
    to the corresponding arp entry, so call it only in/near the *resolve()
    routines where it is actually used -- at the moment this is
    arpresolve(), nd6_storelladdr() (the call is embedded here),
    and atmresolve() (the call is just before atmresolve to reduce
    the number of changes).
    This change will make it a lot easier to decouple the arp table
    from the routing table.

    There is an extra call to rt_check() in if_iso88025subr.c to
    determine the routing info length. I have left it alone for
    the time being.

    The interface of arpresolve() and nd6_storelladdr() now changes slightly:
     + the 'rtentry' parameter (really a hint from the upper level layer)
       is now passed unchanged from *_output(), so it becomes the route
       to the final destination and not to the gateway.
     + the routines will return 0 if resolution is possible, non-zero
       otherwise.
     + arpresolve() returns EWOULDBLOCK in case the mbuf is being held
       waiting for an arp reply -- in this case the error code is masked
       in the caller so the upper layer protocol will not see a failure.

2. arpcom untangling
    Where possible, use 'struct ifnet' instead of 'struct arpcom' variables,
    and use the IFP2AC macro to access arpcom fields.
    This mostly affects the netatalk code.

=== Detailed changes: ===
net/if_arcsubr.c
   rt_check() cleanup, remove a useless variable

net/if_atmsubr.c
   rt_check() cleanup

net/if_ethersubr.c
   rt_check() cleanup, arpcom untangling

net/if_fddisubr.c
   rt_check() cleanup, arpcom untangling

net/if_iso88025subr.c
   rt_check() cleanup

netatalk/aarp.c
   arpcom untangling, remove a block of duplicated code

netatalk/at_extern.h
   arpcom untangling

netinet/if_ether.c
   rt_check() cleanup (change arpresolve)

netinet6/nd6.c
   rt_check() cleanup (change nd6_storelladdr)

1 files changed, 7 insertions, 12 deletions

diff --git a/sys/net/if_fddisubr.c b/sys/net/if_fddisubr.c
index d9330ee5..47bf0c3 100644
--- a/sys/net/if_fddisubr.c
+++ b/sys/net/if_fddisubr.c
@@ -117,7 +117,6 @@ fddi_output(ifp, m, dst, rt0)
 	u_int16_t type;
 	int loop_copy = 0, error = 0, hdrcmplt = 0;
  	u_char esrc[FDDI_ADDR_LEN], edst[FDDI_ADDR_LEN];
-	struct rtentry *rt;
 	struct fddi_header *fh;
 
 #ifdef MAC
@@ -132,15 +131,12 @@ fddi_output(ifp, m, dst, rt0)
 		senderr(ENETDOWN);
 	getmicrotime(&ifp->if_lastchange);
 
-	error = rt_check(&rt, &rt0, dst);
-	if (error)
-		goto bad;
-
 	switch (dst->sa_family) {
 #ifdef INET
 	case AF_INET: {
-		if (!arpresolve(ifp, rt, m, dst, edst))
-			return (0);	/* if not yet resolved */
+		error = arpresolve(ifp, rt0, m, dst, edst);
+		if (error)
+			return (error == EWOULDBLOCK ? 0 : error);
 		type = htons(ETHERTYPE_IP);
 		break;
 	}
@@ -174,10 +170,9 @@ fddi_output(ifp, m, dst, rt0)
 #endif /* INET */
 #ifdef INET6
 	case AF_INET6:
-		if (!nd6_storelladdr(ifp, rt, m, dst, (u_char *)edst)) {
-			/* Something bad happened */
-			return (0);
-		}
+		error = nd6_storelladdr(ifp, rt0, m, dst, (u_char *)edst);
+		if (error)
+			return (error); /* Something bad happened */
 		type = htons(ETHERTYPE_IPV6);
 		break;
 #endif /* INET6 */
@@ -191,7 +186,7 @@ fddi_output(ifp, m, dst, rt0)
 #ifdef NETATALK
 	case AF_APPLETALK: {
 	    struct at_ifaddr *aa;
-            if (!aarpresolve(IFP2AC(ifp), m, (struct sockaddr_at *)dst, edst))
+            if (!aarpresolve(ifp, m, (struct sockaddr_at *)dst, edst))
                 return (0);
 	    /*
 	     * ifaddr is the first thing in at_ifaddr