ax25: Stop depending on arp_find

Have ax25_neigh_output perform ordinary arp resolution before calling
ax25_neigh_xmit.

Call dev_hard_header in ax25_neigh_output with a destination address so
it will not fail, and the destination mac address will not need to be
set in ax25_neigh_xmit.

Remove arp_find from ax25_neigh_xmit (the ordinary arp resolution added
to ax25_neigh_output removes the need for calling arp_find).

Document how close ax25_neigh_output is to neigh_resolve_output.

Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-hams@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 12 deletions

diff --git a/net/ax25/ax25_ip.c b/net/ax25/ax25_ip.c
index 08803e820f1d..e030c64ebfb7 100644
--- a/net/ax25/ax25_ip.c
+++ b/net/ax25/ax25_ip.c
@@ -115,9 +115,6 @@ static int ax25_neigh_xmit(struct sk_buff *skb)
         dst = (ax25_address *)(bp + 1);
         src = (ax25_address *)(bp + 8);
 
-        if (arp_find(bp + 1, skb))
-                return 1;
-
         route = ax25_get_route(dst, NULL);
         if (route) {
                 digipeat = route->digipeat;
@@ -218,16 +215,35 @@ put:
 
 static int ax25_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
 {
-        struct net_device *dev = skb->dev;
-
-        __skb_pull(skb, skb_network_offset(skb));
-
-        if (dev_hard_header(skb, dev, ntohs(skb->protocol), NULL, NULL,
-                            skb->len) < 0 &&
-            ax25_neigh_xmit(skb));
-                return 0;
+        /* Except for calling ax25_neigh_xmit instead of
+         * dev_queue_xmit this is neigh_resolve_output.
+         */
+        int rc = 0;
+
+        if (!neigh_event_send(neigh, skb)) {
+                int err;
+                struct net_device *dev = neigh->dev;
+                unsigned int seq;
+
+                do {
+                        __skb_pull(skb, skb_network_offset(skb));
+                        seq = read_seqbegin(&neigh->ha_lock);
+                        err = dev_hard_header(skb, dev, ntohs(skb->protocol),
+                                              neigh->ha, NULL, skb->len);
+                } while (read_seqretry(&neigh->ha_lock, seq));
+
+                if (err >= 0) {
+                        ax25_neigh_xmit(skb);
+                } else
+                        goto out_kfree_skb;
+        }
+out:
+        return rc;
 
-        return dev_queue_xmit(skb);
+out_kfree_skb:
+        rc = -EINVAL;
+        kfree_skb(skb);
+        goto out;
 }
 
 int ax25_neigh_construct(struct neighbour *neigh)