linux/net/batman-adv/distributed-arp-table.h
Linus Lüssing b61ec31c85 batman-adv: Snoop DHCPACKs for DAT
In a 1000 nodes mesh network (Freifunk Hamburg) we can still see
30KBit/s of ARP traffic (equalling about 25% of all layer two
specific overhead, remaining after some filtering) flooded through
the mesh. These 30KBit/s are mainly ARP Requests from the
gateways / DHCP servers.

By snooping DHCPACKs we can learn about MAC/IP address pairs
in the DHCP range without relying on ARP. This patch is in preparation
to eliminate the need for mesh wide message flooding for IPv4 address
resolution.

Also this allows to quickly update a MAC/IP pair at least in the DHT when
DHCP reassigns an IP address to a new host.

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>
2018-12-30 18:14:42 +01:00

207 lines
5.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2011-2018 B.A.T.M.A.N. contributors:
*
* Antonio Quartulli
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_
#define _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_
#include "main.h"
#include <linux/compiler.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <uapi/linux/batadv_packet.h>
#include "originator.h"
struct netlink_callback;
struct seq_file;
struct sk_buff;
#ifdef CONFIG_BATMAN_ADV_DAT
/* BATADV_DAT_ADDR_MAX - maximum address value in the DHT space */
#define BATADV_DAT_ADDR_MAX ((batadv_dat_addr_t)~(batadv_dat_addr_t)0)
void batadv_dat_status_update(struct net_device *net_dev);
bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
struct sk_buff *skb);
bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size);
void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
struct sk_buff *skb);
bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size);
void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv,
struct sk_buff *skb,
__be16 proto,
unsigned short vid);
void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size);
bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
struct batadv_forw_packet *forw_packet);
/**
* batadv_dat_init_orig_node_addr() - assign a DAT address to the orig_node
* @orig_node: the node to assign the DAT address to
*/
static inline void
batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
{
u32 addr;
addr = batadv_choose_orig(orig_node->orig, BATADV_DAT_ADDR_MAX);
orig_node->dat_addr = (batadv_dat_addr_t)addr;
}
/**
* batadv_dat_init_own_addr() - assign a DAT address to the node itself
* @bat_priv: the bat priv with all the soft interface information
* @primary_if: a pointer to the primary interface
*/
static inline void
batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if)
{
u32 addr;
addr = batadv_choose_orig(primary_if->net_dev->dev_addr,
BATADV_DAT_ADDR_MAX);
bat_priv->dat.addr = (batadv_dat_addr_t)addr;
}
int batadv_dat_init(struct batadv_priv *bat_priv);
void batadv_dat_free(struct batadv_priv *bat_priv);
int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset);
int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb);
/**
* batadv_dat_inc_counter() - increment the correct DAT packet counter
* @bat_priv: the bat priv with all the soft interface information
* @subtype: the 4addr subtype of the packet to be counted
*
* Updates the ethtool statistics for the received packet if it is a DAT subtype
*/
static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
u8 subtype)
{
switch (subtype) {
case BATADV_P_DAT_DHT_GET:
batadv_inc_counter(bat_priv,
BATADV_CNT_DAT_GET_RX);
break;
case BATADV_P_DAT_DHT_PUT:
batadv_inc_counter(bat_priv,
BATADV_CNT_DAT_PUT_RX);
break;
}
}
#else
static inline void batadv_dat_status_update(struct net_device *net_dev)
{
}
static inline bool
batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
return false;
}
static inline bool
batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
return false;
}
static inline bool
batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
struct sk_buff *skb)
{
return false;
}
static inline bool
batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
return false;
}
static inline void
batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv,
struct sk_buff *skb, __be16 proto,
unsigned short vid)
{
}
static inline void
batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
}
static inline bool
batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
struct batadv_forw_packet *forw_packet)
{
return false;
}
static inline void
batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
{
}
static inline void batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
struct batadv_hard_iface *iface)
{
}
static inline void batadv_arp_change_timeout(struct net_device *soft_iface,
const char *name)
{
}
static inline int batadv_dat_init(struct batadv_priv *bat_priv)
{
return 0;
}
static inline void batadv_dat_free(struct batadv_priv *bat_priv)
{
}
static inline int
batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb)
{
return -EOPNOTSUPP;
}
static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
u8 subtype)
{
}
#endif /* CONFIG_BATMAN_ADV_DAT */
#endif /* _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_ */