diff options
Diffstat (limited to 'net/batman-adv')
| -rw-r--r-- | net/batman-adv/bat_v_elp.c | 69 | ||||
| -rw-r--r-- | net/batman-adv/main.h | 3 |
2 files changed, 72 insertions, 0 deletions
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 8376730ebd69..3844e7efd0b0 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -165,6 +165,69 @@ void batadv_v_elp_throughput_metric_update(struct work_struct *work) } /** + * 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_netdev(hard_iface->net_dev)) + 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), + BATADV_ELP_MIN_PROBE_SIZE); + + 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, + GFP_ATOMIC); + 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(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 * @@ -227,6 +290,12 @@ static void batadv_v_elp_periodic_work(struct work_struct *work) */ rcu_read_lock(); 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 + */ + break; + if (!kref_get_unless_zero(&hardif_neigh->refcount)) continue; diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h index 5c68bf2618c7..878c35974845 100644 --- a/net/batman-adv/main.h +++ b/net/batman-adv/main.h @@ -63,6 +63,9 @@ /* B.A.T.M.A.N. V */ #define BATADV_THROUGHPUT_DEFAULT_VALUE 10 /* 1 Mbps */ +#define BATADV_ELP_PROBES_PER_NODE 2 +#define BATADV_ELP_MIN_PROBE_SIZE 200 /* bytes */ +#define BATADV_ELP_PROBE_MAX_TX_DIFF 100 /* milliseconds */ #define BATADV_ELP_MAX_AGE 64 #define BATADV_OGM_MAX_ORIGDIFF 5 #define BATADV_OGM_MAX_AGE 64 |