linux-stable/net/batman-adv/bridge_loop_avoidance.h
Linus Lüssing 74c09b7275 batman-adv: mcast: fix duplicate mcast packets in BLA backbone from mesh
Scenario:
* Multicast frame send from mesh to a BLA backbone (multiple nodes
  with their bat0 bridged together, with BLA enabled)

Issue:
* BLA backbone nodes receive the frame multiple times on bat0,
  once from mesh->bat0 and once from each backbone_gw from LAN

For unicast, a node will send only to the best backbone gateway
according to the TQ. However for multicast we currently cannot determine
if multiple destination nodes share the same backbone if they don't share
the same backbone with us. So we need to keep sending the unicasts to
all backbone gateways and let the backbone gateways decide which one
will forward the frame. We can use the CLAIM mechanism to make this
decision.

One catch: The batman-adv gateway feature for DHCP packets potentially
sends multicast packets in the same batman-adv unicast header as the
multicast optimizations code. And we are not allowed to drop those even
if we did not claim the source address of the sender, as for such
packets there is only this one multicast-in-unicast packet.

How can we distinguish the two cases?

The gateway feature uses a batman-adv unicast 4 address header. While
the multicast-to-unicasts feature uses a simple, 3 address batman-adv
unicast header. So let's use this to distinguish.

Fixes: fe2da6ff27 ("batman-adv: check incoming packet type for bla")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-09-15 10:05:24 +02:00

149 lines
3.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2011-2020 B.A.T.M.A.N. contributors:
*
* Simon Wunderlich
*/
#ifndef _NET_BATMAN_ADV_BLA_H_
#define _NET_BATMAN_ADV_BLA_H_
#include "main.h"
#include <linux/compiler.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/stddef.h>
#include <linux/types.h>
/**
* batadv_bla_is_loopdetect_mac() - check if the mac address is from a loop
* detect frame sent by bridge loop avoidance
* @mac: mac address to check
*
* Return: true if the it looks like a loop detect frame
* (mac starts with BA:BE), false otherwise
*/
static inline bool batadv_bla_is_loopdetect_mac(const uint8_t *mac)
{
if (mac[0] == 0xba && mac[1] == 0xbe)
return true;
return false;
}
#ifdef CONFIG_BATMAN_ADV_BLA
bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
unsigned short vid, int packet_type);
bool batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
unsigned short vid);
bool batadv_bla_is_backbone_gw(struct sk_buff *skb,
struct batadv_orig_node *orig_node,
int hdr_size);
int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset);
int batadv_bla_claim_dump(struct sk_buff *msg, struct netlink_callback *cb);
int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq,
void *offset);
int batadv_bla_backbone_dump(struct sk_buff *msg, struct netlink_callback *cb);
bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, u8 *orig,
unsigned short vid);
bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
struct sk_buff *skb);
void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
struct batadv_hard_iface *oldif);
void batadv_bla_status_update(struct net_device *net_dev);
int batadv_bla_init(struct batadv_priv *bat_priv);
void batadv_bla_free(struct batadv_priv *bat_priv);
int batadv_bla_claim_dump(struct sk_buff *msg, struct netlink_callback *cb);
#ifdef CONFIG_BATMAN_ADV_DAT
bool batadv_bla_check_claim(struct batadv_priv *bat_priv, u8 *addr,
unsigned short vid);
#endif
#define BATADV_BLA_CRC_INIT 0
#else /* ifdef CONFIG_BATMAN_ADV_BLA */
static inline bool batadv_bla_rx(struct batadv_priv *bat_priv,
struct sk_buff *skb, unsigned short vid,
int packet_type)
{
return false;
}
static inline bool batadv_bla_tx(struct batadv_priv *bat_priv,
struct sk_buff *skb, unsigned short vid)
{
return false;
}
static inline bool batadv_bla_is_backbone_gw(struct sk_buff *skb,
struct batadv_orig_node *orig_node,
int hdr_size)
{
return false;
}
static inline int batadv_bla_claim_table_seq_print_text(struct seq_file *seq,
void *offset)
{
return 0;
}
static inline int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq,
void *offset)
{
return 0;
}
static inline bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv,
u8 *orig, unsigned short vid)
{
return false;
}
static inline bool
batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
return false;
}
static inline void
batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
struct batadv_hard_iface *oldif)
{
}
static inline int batadv_bla_init(struct batadv_priv *bat_priv)
{
return 1;
}
static inline void batadv_bla_free(struct batadv_priv *bat_priv)
{
}
static inline int batadv_bla_claim_dump(struct sk_buff *msg,
struct netlink_callback *cb)
{
return -EOPNOTSUPP;
}
static inline int batadv_bla_backbone_dump(struct sk_buff *msg,
struct netlink_callback *cb)
{
return -EOPNOTSUPP;
}
static inline
bool batadv_bla_check_claim(struct batadv_priv *bat_priv, u8 *addr,
unsigned short vid)
{
return true;
}
#endif /* ifdef CONFIG_BATMAN_ADV_BLA */
#endif /* ifndef _NET_BATMAN_ADV_BLA_H_ */