batman-adv: Add wrapper to look up neighbor and send skb

By adding batadv_send_skb_to_orig() in send.c, we can remove duplicate
code that looks up the next hop and then calls batadv_send_skb_packet().

Furthermore, this prepares the upcoming new implementation of
fragmentation, which requires the next hop to route packets.

Please note that this doesn't entirely remove the next-hop lookup in
routing.c and unicast.c, since it is used by the current fragmentation
code.

Also note that the next-hop info is removed from debug messages in
translation-table.c, since it is looked up elsewhere.

Signed-off-by: Martin Hundebøll <[e-mail]>
Signed-off-by: Marek Lindner <[e-mail]>
Signed-off-by: Antonio Quartulli <[e-mail]>

net/batman-adv/routing.c

···
 {
 	struct batadv_hard_iface *primary_if = NULL;
 	struct batadv_orig_node *orig_node = NULL;
-	struct batadv_neigh_node *router = NULL;
 	struct batadv_icmp_packet_rr *icmp_packet;
 	int ret = NET_RX_DROP;
 
···
 	if (!orig_node)
 		goto out;
 
-	router = batadv_orig_node_get_router(orig_node);
-	if (!router)
-		goto out;
-
 	/* create a copy of the skb, if needed, to modify it. */
 	if (skb_cow(skb, ETH_HLEN) < 0)
 		goto out;
···
 	icmp_packet->msg_type = BATADV_ECHO_REPLY;
 	icmp_packet->header.ttl = BATADV_TTL;
 
-	batadv_send_skb_packet(skb, router->if_incoming, router->addr);
-	ret = NET_RX_SUCCESS;
+	if (batadv_send_skb_to_orig(skb, orig_node, NULL))
+		ret = NET_RX_SUCCESS;
 
 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
-	if (router)
-		batadv_neigh_node_free_ref(router);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
 	return ret;
···
 {
 	struct batadv_hard_iface *primary_if = NULL;
 	struct batadv_orig_node *orig_node = NULL;
-	struct batadv_neigh_node *router = NULL;
 	struct batadv_icmp_packet *icmp_packet;
 	int ret = NET_RX_DROP;
 
···
 	if (!orig_node)
 		goto out;
 
-	router = batadv_orig_node_get_router(orig_node);
-	if (!router)
-		goto out;
-
 	/* create a copy of the skb, if needed, to modify it. */
 	if (skb_cow(skb, ETH_HLEN) < 0)
 		goto out;
···
 	icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 	icmp_packet->header.ttl = BATADV_TTL;
 
-	batadv_send_skb_packet(skb, router->if_incoming, router->addr);
-	ret = NET_RX_SUCCESS;
+	if (batadv_send_skb_to_orig(skb, orig_node, NULL))
+		ret = NET_RX_SUCCESS;
 
 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
-	if (router)
-		batadv_neigh_node_free_ref(router);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
 	return ret;
···
 	struct batadv_icmp_packet_rr *icmp_packet;
 	struct ethhdr *ethhdr;
 	struct batadv_orig_node *orig_node = NULL;
-	struct batadv_neigh_node *router = NULL;
 	int hdr_size = sizeof(struct batadv_icmp_packet);
 	int ret = NET_RX_DROP;
 
···
 	if (!orig_node)
 		goto out;
 
-	router = batadv_orig_node_get_router(orig_node);
-	if (!router)
-		goto out;
-
 	/* create a copy of the skb, if needed, to modify it. */
 	if (skb_cow(skb, ETH_HLEN) < 0)
 		goto out;
···
 	icmp_packet->header.ttl--;
 
 	/* route it */
-	batadv_send_skb_packet(skb, router->if_incoming, router->addr);
-	ret = NET_RX_SUCCESS;
+	if (batadv_send_skb_to_orig(skb, orig_node, recv_if))
+		ret = NET_RX_SUCCESS;
 
 out:
-	if (router)
-		batadv_neigh_node_free_ref(router);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
 	return ret;
···
 			   skb->len + ETH_HLEN);
 
 	/* route it */
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = NET_RX_SUCCESS;
+	if (batadv_send_skb_to_orig(skb, orig_node, recv_if))
+		ret = NET_RX_SUCCESS;
 
 out:
 	if (neigh_node)

net/batman-adv/send.c

···
 	return NET_XMIT_DROP;
 }
 
+/**
+ * batadv_send_skb_to_orig - Lookup next-hop and transmit skb.
+ * @skb: Packet to be transmitted.
+ * @orig_node: Final destination of the packet.
+ * @recv_if: Interface used when receiving the packet (can be NULL).
+ *
+ * Looks up the best next-hop towards the passed originator and passes the
+ * skb on for preparation of MAC header. If the packet originated from this
+ * host, NULL can be passed as recv_if and no interface alternating is
+ * attempted.
+ *
+ * Returns TRUE on success; FALSE otherwise.
+ */
+bool batadv_send_skb_to_orig(struct sk_buff *skb,
+			     struct batadv_orig_node *orig_node,
+			     struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = orig_node->bat_priv;
+	struct batadv_neigh_node *neigh_node;
+
+	/* batadv_find_router() increases neigh_nodes refcount if found. */
+	neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
+	if (!neigh_node)
+		return false;
+
+	/* route it */
+	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
+
+	batadv_neigh_node_free_ref(neigh_node);
+
+	return true;
+}
+
 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);

net/batman-adv/send.h

···
 int batadv_send_skb_packet(struct sk_buff *skb,
 			   struct batadv_hard_iface *hard_iface,
 			   const uint8_t *dst_addr);
+bool batadv_send_skb_to_orig(struct sk_buff *skb,
+			     struct batadv_orig_node *orig_node,
+			     struct batadv_hard_iface *recv_if);
 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface);
 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
 				    const struct sk_buff *skb,

net/batman-adv/translation-table.c

···
 {
 	struct sk_buff *skb = NULL;
 	struct batadv_tt_query_packet *tt_request;
-	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_hard_iface *primary_if;
 	struct batadv_tt_req_node *tt_req_node = NULL;
 	int ret = 1;
···
 	if (full_table)
 		tt_request->flags |= BATADV_TT_FULL_TABLE;
 
-	neigh_node = batadv_orig_node_get_router(dst_orig_node);
-	if (!neigh_node)
-		goto out;
-
-	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Sending TT_REQUEST to %pM via %pM [%c]\n",
-		   dst_orig_node->orig, neigh_node->addr,
-		   (full_table ? 'F' : '.'));
+	batadv_dbg(BATADV_DBG_TT, bat_priv, "Sending TT_REQUEST to %pM [%c]\n",
+		   dst_orig_node->orig, (full_table ? 'F' : '.'));
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_TX);
 
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = 0;
+	if (batadv_send_skb_to_orig(skb, dst_orig_node, NULL))
+		ret = 0;
 
 out:
-	if (neigh_node)
-		batadv_neigh_node_free_ref(neigh_node);
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 	if (ret)
···
 {
 	struct batadv_orig_node *req_dst_orig_node;
 	struct batadv_orig_node *res_dst_orig_node = NULL;
-	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_hard_iface *primary_if = NULL;
 	uint8_t orig_ttvn, req_ttvn, ttvn;
 	int ret = false;
···
 
 	res_dst_orig_node = batadv_orig_hash_find(bat_priv, tt_request->src);
 	if (!res_dst_orig_node)
-		goto out;
-
-	neigh_node = batadv_orig_node_get_router(res_dst_orig_node);
-	if (!neigh_node)
 		goto out;
 
 	primary_if = batadv_primary_if_get_selected(bat_priv);
···
 		tt_response->flags |= BATADV_TT_FULL_TABLE;
 
 	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Sending TT_RESPONSE %pM via %pM for %pM (ttvn: %u)\n",
-		   res_dst_orig_node->orig, neigh_node->addr,
-		   req_dst_orig_node->orig, req_ttvn);
+		   "Sending TT_RESPONSE %pM for %pM (ttvn: %u)\n",
+		   res_dst_orig_node->orig, req_dst_orig_node->orig, req_ttvn);
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);
 
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = true;
+	if (batadv_send_skb_to_orig(skb, res_dst_orig_node, NULL))
+		ret = true;
 	goto out;
 
 unlock:
···
 		batadv_orig_node_free_ref(res_dst_orig_node);
 	if (req_dst_orig_node)
 		batadv_orig_node_free_ref(req_dst_orig_node);
-	if (neigh_node)
-		batadv_neigh_node_free_ref(neigh_node);
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 	if (!ret)
···
 			   struct batadv_tt_query_packet *tt_request)
 {
 	struct batadv_orig_node *orig_node;
-	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_hard_iface *primary_if = NULL;
 	uint8_t my_ttvn, req_ttvn, ttvn;
 	int ret = false;
···
 
 	orig_node = batadv_orig_hash_find(bat_priv, tt_request->src);
 	if (!orig_node)
-		goto out;
-
-	neigh_node = batadv_orig_node_get_router(orig_node);
-	if (!neigh_node)
 		goto out;
 
 	primary_if = batadv_primary_if_get_selected(bat_priv);
···
 		tt_response->flags |= BATADV_TT_FULL_TABLE;
 
 	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Sending TT_RESPONSE to %pM via %pM [%c]\n",
-		   orig_node->orig, neigh_node->addr,
+		   "Sending TT_RESPONSE to %pM [%c]\n",
+		   orig_node->orig,
 		   (tt_response->flags & BATADV_TT_FULL_TABLE ? 'F' : '.'));
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);
 
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = true;
+	if (batadv_send_skb_to_orig(skb, orig_node, NULL))
+		ret = true;
 	goto out;
 
 unlock:
···
 out:
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
-	if (neigh_node)
-		batadv_neigh_node_free_ref(neigh_node);
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 	if (!ret)
···
 static void batadv_send_roam_adv(struct batadv_priv *bat_priv, uint8_t *client,
 				 struct batadv_orig_node *orig_node)
 {
-	struct batadv_neigh_node *neigh_node = NULL;
 	struct sk_buff *skb = NULL;
 	struct batadv_roam_adv_packet *roam_adv_packet;
 	int ret = 1;
···
 	memcpy(roam_adv_packet->dst, orig_node->orig, ETH_ALEN);
 	memcpy(roam_adv_packet->client, client, ETH_ALEN);
 
-	neigh_node = batadv_orig_node_get_router(orig_node);
-	if (!neigh_node)
-		goto out;
-
 	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Sending ROAMING_ADV to %pM (client %pM) via %pM\n",
-		   orig_node->orig, client, neigh_node->addr);
+		   "Sending ROAMING_ADV to %pM (client %pM)\n",
+		   orig_node->orig, client);
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_TX);
 
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = 0;
+	if (batadv_send_skb_to_orig(skb, orig_node, NULL))
+		ret = 0;
 
 out:
-	if (neigh_node)
-		batadv_neigh_node_free_ref(neigh_node);
-	if (ret)
+	if (ret && skb)
 		kfree_skb(skb);
 	return;
 }

net/batman-adv/unicast.c

···
 	struct batadv_orig_node *orig_node;
 	struct batadv_neigh_node *neigh_node;
 	int data_len = skb->len;
-	int ret = 1;
+	int ret = NET_RX_DROP;
 	unsigned int dev_mtu;
 
 	/* get routing information */
···
 		goto out;
 	}
 
-	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
-	ret = 0;
+	if (batadv_send_skb_to_orig(skb, orig_node, NULL))
+		ret = 0;
 
 out:
 	if (neigh_node)
 		batadv_neigh_node_free_ref(neigh_node);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
-	if (ret == 1)
+	if (ret == NET_RX_DROP)
 		kfree_skb(skb);
 	return ret;
 }

net/batman-adv/vis.c

···
 static void batadv_broadcast_vis_packet(struct batadv_priv *bat_priv,
 					struct batadv_vis_info *info)
 {
-	struct batadv_neigh_node *router;
 	struct batadv_hashtable *hash = bat_priv->orig_hash;
 	struct hlist_node *node;
 	struct hlist_head *head;
 	struct batadv_orig_node *orig_node;
 	struct batadv_vis_packet *packet;
 	struct sk_buff *skb;
-	struct batadv_hard_iface *hard_iface;
-	uint8_t dstaddr[ETH_ALEN];
 	uint32_t i;
 
 
···
 			if (!(orig_node->flags & BATADV_VIS_SERVER))
 				continue;
 
-			router = batadv_orig_node_get_router(orig_node);
-			if (!router)
-				continue;
-
 			/* don't send it if we already received the packet from
 			 * this node.
 			 */
 			if (batadv_recv_list_is_in(bat_priv, &info->recv_list,
-						   orig_node->orig)) {
-				batadv_neigh_node_free_ref(router);
+						   orig_node->orig))
 				continue;
-			}
 
 			memcpy(packet->target_orig, orig_node->orig, ETH_ALEN);
-			hard_iface = router->if_incoming;
-			memcpy(dstaddr, router->addr, ETH_ALEN);
-
-			batadv_neigh_node_free_ref(router);
-
 			skb = skb_clone(info->skb_packet, GFP_ATOMIC);
-			if (skb)
-				batadv_send_skb_packet(skb, hard_iface,
-						       dstaddr);
+			if (!skb)
+				continue;
 
+			if (!batadv_send_skb_to_orig(skb, orig_node, NULL))
+				kfree_skb(skb);
 		}
 		rcu_read_unlock();
 	}
···
 				      struct batadv_vis_info *info)
 {
 	struct batadv_orig_node *orig_node;
-	struct batadv_neigh_node *router = NULL;
 	struct sk_buff *skb;
 	struct batadv_vis_packet *packet;
 
···
 	if (!orig_node)
 		goto out;
 
-	router = batadv_orig_node_get_router(orig_node);
-	if (!router)
+	skb = skb_clone(info->skb_packet, GFP_ATOMIC);
+	if (!skb)
 		goto out;
 
-	skb = skb_clone(info->skb_packet, GFP_ATOMIC);
-	if (skb)
-		batadv_send_skb_packet(skb, router->if_incoming, router->addr);
+	if (!batadv_send_skb_to_orig(skb, orig_node, NULL))
+		kfree_skb(skb);
 
 out:
-	if (router)
-		batadv_neigh_node_free_ref(router);
 	if (orig_node)
 		batadv_orig_node_free_ref(orig_node);
 }