blob: 2614a9caee008539cc489b71dabdc36ac0ae3752 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2011-2019 B.A.T.M.A.N. contributors:
* Linus L├╝ssing, Marek Lindner
#include "bat_v_elp.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/nl80211.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/cfg80211.h>
#include <uapi/linux/batadv_packet.h>
#include "bat_algo.h"
#include "bat_v_ogm.h"
#include "hard-interface.h"
#include "log.h"
#include "originator.h"
#include "routing.h"
#include "send.h"
* batadv_v_elp_start_timer() - restart timer for ELP periodic work
* @hard_iface: the interface for which the timer has to be reset
static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
unsigned int msecs;
msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
msecs += prandom_u32() % (2 * BATADV_JITTER);
queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
* batadv_v_elp_get_throughput() - get the throughput towards a neighbour
* @neigh: the neighbour for which the throughput has to be obtained
* Return: The throughput towards the given neighbour in multiples of 100kpbs
* (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
struct batadv_hard_iface *hard_iface = neigh->if_incoming;
struct ethtool_link_ksettings link_settings;
struct net_device *real_netdev;
struct station_info sinfo;
u32 throughput;
int ret;
/* if the user specified a customised value for this interface, then
* return it directly
throughput = atomic_read(&hard_iface->bat_v.throughput_override);
if (throughput != 0)
return throughput;
/* if this is a wireless device, then ask its throughput through
* cfg80211 API
if (batadv_is_wifi_hardif(hard_iface)) {
if (!batadv_is_cfg80211_hardif(hard_iface))
/* unsupported WiFi driver version */
goto default_throughput;
real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
if (!real_netdev)
goto default_throughput;
ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
if (!ret) {
/* free the TID stats immediately */
if (ret == -ENOENT) {
/* Node is not associated anymore! It would be
* possible to delete this neighbor. For now set
* the throughput metric to 0.
return 0;
if (ret)
goto default_throughput;
if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
goto default_throughput;
return sinfo.expected_throughput / 100;
/* if not a wifi interface, check if this device provides data via
* ethtool (e.g. an Ethernet adapter)
memset(&link_settings, 0, sizeof(link_settings));
ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
/* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
* tend to initialize the interface throughput with some value for the
* sake of having a throughput number to export via ethtool. This
* exported throughput leaves batman-adv to conclude the interface
* throughput is genuine (reflecting reality), thus no measurements
* are necessary.
* Based on the observation that those interface types also tend to set
* the link auto-negotiation to 'off', batman-adv shall check this
* setting to differentiate between genuine link throughput information
* and placeholders installed by virtual interfaces.
if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
/* link characteristics might change over time */
if (link_settings.base.duplex == DUPLEX_FULL)
hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
throughput = link_settings.base.speed;
if (throughput && throughput != SPEED_UNKNOWN)
return throughput * 10;
if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
"WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n",
hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
/* if none of the above cases apply, return the base_throughput */
* batadv_v_elp_throughput_metric_update() - worker updating the throughput
* metric of a single hop neighbour
* @work: the work queue item
void batadv_v_elp_throughput_metric_update(struct work_struct *work)
struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
struct batadv_hardif_neigh_node *neigh;
neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
/* decrement refcounter to balance increment performed before scheduling
* this task
* batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
* @neigh: the neighbour to probe
* Sends a predefined number of unicast wifi packets to a given neighbour in
* order to trigger the throughput estimation on this link by the RC algorithm.
* Packets are sent only if there there is not enough payload unicast traffic
* towards this neighbour..
* Return: True on success and false in case of error during skb preparation.
static bool
batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
struct batadv_hard_iface *hard_iface = neigh->if_incoming;
struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
unsigned long last_tx_diff;
struct sk_buff *skb;
int probe_len, i;
int elp_skb_len;
/* this probing routine is for Wifi neighbours only */
if (!batadv_is_wifi_hardif(hard_iface))
return true;
/* probe the neighbor only if no unicast packets have been sent
* to it in the last 100 milliseconds: this is the rate control
* algorithm sampling interval (minstrel). In this way, if not
* enough traffic has been sent to the neighbor, batman-adv can
* generate 2 probe packets and push the RC algorithm to perform
* the sampling
last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
return true;
probe_len = max_t(int, sizeof(struct batadv_elp_packet),
for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
elp_skb_len = hard_iface->bat_v.elp_skb->len;
skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
probe_len - elp_skb_len,
if (!skb)
return false;
/* Tell the skb to get as big as the allocated space (we want
* the packet to be exactly of that size to make the link
* throughput estimation effective.
skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"Sending unicast (probe) ELP packet on interface %s to %pM\n",
hard_iface->net_dev->name, neigh->addr);
batadv_send_skb_packet(skb, hard_iface, neigh->addr);
return true;
* batadv_v_elp_periodic_work() - ELP periodic task per interface
* @work: work queue item
* Emits broadcast ELP message in regular intervals.
static void batadv_v_elp_periodic_work(struct work_struct *work)
struct batadv_hardif_neigh_node *hardif_neigh;
struct batadv_hard_iface *hard_iface;
struct batadv_hard_iface_bat_v *bat_v;
struct batadv_elp_packet *elp_packet;
struct batadv_priv *bat_priv;
struct sk_buff *skb;
u32 elp_interval;
bool ret;
bat_v = container_of(work, struct batadv_hard_iface_bat_v,;
hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
bat_priv = netdev_priv(hard_iface->soft_iface);
if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
goto out;
/* we are in the process of shutting this interface down */
if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
goto out;
/* the interface was enabled but may not be ready yet */
if (hard_iface->if_status != BATADV_IF_ACTIVE)
goto restart_timer;
skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
if (!skb)
goto restart_timer;
elp_packet = (struct batadv_elp_packet *)skb->data;
elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
elp_packet->elp_interval = htonl(elp_interval);
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"Sending broadcast ELP packet on interface %s, seqno %u\n",
batadv_send_broadcast_skb(skb, hard_iface);
/* The throughput metric is updated on each sent packet. This way, if a
* node is dead and no longer sends packets, batman-adv is still able to
* react timely to its death.
* The throughput metric is updated by following these steps:
* 1) if the hard_iface is wifi => send a number of unicast ELPs for
* probing/sampling to each neighbor
* 2) update the throughput metric value of each neighbor (note that the
* value retrieved in this step might be 100ms old because the
* probing packets at point 1) could still be in the HW queue)
hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
/* if something goes wrong while probing, better to stop
* sending packets immediately and reschedule the task
if (!kref_get_unless_zero(&hardif_neigh->refcount))
/* Reading the estimated throughput from cfg80211 is a task that
* may sleep and that is not allowed in an rcu protected
* context. Therefore schedule a task for that.
ret = queue_work(batadv_event_workqueue,
if (!ret)
* batadv_v_elp_iface_enable() - setup the ELP interface private resources
* @hard_iface: interface for which the data has to be prepared
* Return: 0 on success or a -ENOMEM in case of failure.
int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
static const size_t tvlv_padding = sizeof(__be32);
struct batadv_elp_packet *elp_packet;
unsigned char *elp_buff;
u32 random_seqno;
size_t size;
int res = -ENOMEM;
size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
if (!hard_iface->bat_v.elp_skb)
goto out;
skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
BATADV_ELP_HLEN + tvlv_padding);
elp_packet = (struct batadv_elp_packet *)elp_buff;
elp_packet->packet_type = BATADV_ELP;
elp_packet->version = BATADV_COMPAT_VERSION;
/* randomize initial seqno to avoid collision */
get_random_bytes(&random_seqno, sizeof(random_seqno));
atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
/* assume full-duplex by default */
hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
/* warn the user (again) if there is no throughput data is available */
hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
if (batadv_is_wifi_hardif(hard_iface))
hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
res = 0;
return res;
* batadv_v_elp_iface_disable() - release ELP interface private resources
* @hard_iface: interface for which the resources have to be released
void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
hard_iface->bat_v.elp_skb = NULL;
* batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
* hard-interface
* @primary_iface: the new primary interface
* @hard_iface: interface holding the to-be-updated buffer
void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
struct batadv_hard_iface *hard_iface)
struct batadv_elp_packet *elp_packet;
struct sk_buff *skb;
if (!hard_iface->bat_v.elp_skb)
skb = hard_iface->bat_v.elp_skb;
elp_packet = (struct batadv_elp_packet *)skb->data;
* batadv_v_elp_primary_iface_set() - change internal data to reflect the new
* primary interface
* @primary_iface: the new primary interface
void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
struct batadv_hard_iface *hard_iface;
/* update orig field of every elp iface belonging to this mesh */
list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
if (primary_iface->soft_iface != hard_iface->soft_iface)
batadv_v_elp_iface_activate(primary_iface, hard_iface);
* batadv_v_elp_neigh_update() - update an ELP neighbour node
* @bat_priv: the bat priv with all the soft interface information
* @neigh_addr: the neighbour interface address
* @if_incoming: the interface the packet was received through
* @elp_packet: the received ELP packet
* Updates the ELP neighbour node state with the data received within the new
* ELP packet.
static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
u8 *neigh_addr,
struct batadv_hard_iface *if_incoming,
struct batadv_elp_packet *elp_packet)
struct batadv_neigh_node *neigh;
struct batadv_orig_node *orig_neigh;
struct batadv_hardif_neigh_node *hardif_neigh;
s32 seqno_diff;
s32 elp_latest_seqno;
orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
if (!orig_neigh)
neigh = batadv_neigh_node_get_or_create(orig_neigh,
if_incoming, neigh_addr);
if (!neigh)
goto orig_free;
hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
if (!hardif_neigh)
goto neigh_free;
elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
/* known or older sequence numbers are ignored. However always adopt
* if the router seems to have been restarted.
if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
goto hardif_free;
neigh->last_seen = jiffies;
hardif_neigh->last_seen = jiffies;
hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
if (hardif_neigh)
if (neigh)
if (orig_neigh)
* batadv_v_elp_packet_recv() - main ELP packet handler
* @skb: the received packet
* @if_incoming: the interface this packet was received through
* Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
* processed or NET_RX_DROP in case of failure.
int batadv_v_elp_packet_recv(struct sk_buff *skb,
struct batadv_hard_iface *if_incoming)
struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
struct batadv_elp_packet *elp_packet;
struct batadv_hard_iface *primary_if;
struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
bool res;
int ret = NET_RX_DROP;
res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
if (!res)
goto free_skb;
if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
goto free_skb;
/* did we receive a B.A.T.M.A.N. V ELP packet on an interface
* that does not have B.A.T.M.A.N. V ELP enabled ?
if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
goto free_skb;
elp_packet = (struct batadv_elp_packet *)skb->data;
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"Received ELP packet from %pM seqno %u ORIG: %pM\n",
ethhdr->h_source, ntohl(elp_packet->seqno),
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto free_skb;
batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
if (ret == NET_RX_SUCCESS)
return ret;