batman-adv: remove network coding support

The Network Coding feature, introduced in 2013, is based on the master
thesis "Inter-Flow Network Coding for Wireless Mesh Networks". It relies on
the assumption that neighboring mesh nodes can reliably overhear each
other's transmissions in promiscuous mode, allowing packets to be combined
to reduce forwarding overhead.

This assumption no longer holds for modern wireless mesh networks, which
are heterogeneous and make overhearing increasingly unreliable. Factors
such as multiple spatial streams, varying data rates, beamforming, and
OFDMA all prevent nodes from consistently overhearing each other. The current
implementation in batman-adv is not able to detect these conditions and would
require a more complex layer beyond its neighbor discovery process to do so.

In addition, the feature has been unmaintained for years and is discouraged
for use. None of the current maintainers have the required test
setup to verify its functionality, and known issues remain in its data
structures (reference counting, RCU usage, and cleanup handling). Its
continued presence also blocks necessary refactoring of the core originator
infrastructure.

Remove this obsolete and unmaintained feature.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Acked-by: Marek Lindner <marek.lindner@mailbox.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 0 insertions, 106 deletions

diff --git a/net/batman-adv/network-coding.h b/net/batman-adv/network-coding.h
deleted file mode 100644
index 368cc3130e4c..000000000000
--- a/net/batman-adv/network-coding.h
+++ /dev/null
@@ -1,106 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright (C) B.A.T.M.A.N. contributors:
- *
- * Martin Hundebøll, Jeppe Ledet-Pedersen
- */
-
-#ifndef _NET_BATMAN_ADV_NETWORK_CODING_H_
-#define _NET_BATMAN_ADV_NETWORK_CODING_H_
-
-#include "main.h"
-
-#include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <linux/types.h>
-#include <uapi/linux/batadv_packet.h>
-
-#ifdef CONFIG_BATMAN_ADV_NC
-
-void batadv_nc_status_update(struct net_device *net_dev);
-int batadv_nc_init(void);
-int batadv_nc_mesh_init(struct batadv_priv *bat_priv);
-void batadv_nc_mesh_free(struct batadv_priv *bat_priv);
-void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
-			      struct batadv_orig_node *orig_node,
-			      struct batadv_orig_node *orig_neigh_node,
-			      struct batadv_ogm_packet *ogm_packet,
-			      int is_single_hop_neigh);
-void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
-			  struct batadv_orig_node *orig_node,
-			  bool (*to_purge)(struct batadv_priv *,
-					   struct batadv_nc_node *));
-void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv);
-void batadv_nc_init_orig(struct batadv_orig_node *orig_node);
-bool batadv_nc_skb_forward(struct sk_buff *skb,
-			   struct batadv_neigh_node *neigh_node);
-void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
-				      struct sk_buff *skb);
-void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
-					 struct sk_buff *skb);
-
-#else /* ifdef CONFIG_BATMAN_ADV_NC */
-
-static inline void batadv_nc_status_update(struct net_device *net_dev)
-{
-}
-
-static inline int batadv_nc_init(void)
-{
-	return 0;
-}
-
-static inline int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
-{
-	return 0;
-}
-
-static inline void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
-{
-}
-
-static inline void
-batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
-			 struct batadv_orig_node *orig_node,
-			 struct batadv_orig_node *orig_neigh_node,
-			 struct batadv_ogm_packet *ogm_packet,
-			 int is_single_hop_neigh)
-{
-}
-
-static inline void
-batadv_nc_purge_orig(struct batadv_priv *bat_priv,
-		     struct batadv_orig_node *orig_node,
-		     bool (*to_purge)(struct batadv_priv *,
-				      struct batadv_nc_node *))
-{
-}
-
-static inline void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
-{
-}
-
-static inline void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
-{
-}
-
-static inline bool batadv_nc_skb_forward(struct sk_buff *skb,
-					 struct batadv_neigh_node *neigh_node)
-{
-	return false;
-}
-
-static inline void
-batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
-				 struct sk_buff *skb)
-{
-}
-
-static inline void
-batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
-				    struct sk_buff *skb)
-{
-}
-
-#endif /* ifdef CONFIG_BATMAN_ADV_NC */
-
-#endif /* _NET_BATMAN_ADV_NETWORK_CODING_H_ */