In some setups multiple hard interfaces with similar link qualities or throughput values are available. But people have expressed the desire to consider one of them as a backup only.

Some creative solutions are currently in use: Such people are configuring multiple batman-adv mesh/soft interfaces, wire them together with some veth pairs and then tune the hop penalty to achieve an effect similar to a tunable per interface hop penalty.

This patch introduces a new, configurable, per hard interface hop penalty to simplify such setups.

Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- include/uapi/linux/batman_adv.h | 3 ++- net/batman-adv/bat_iv_ogm.c | 17 +++++++++-------- net/batman-adv/bat_v_ogm.c | 13 ++++++++++--- net/batman-adv/hard-interface.c | 2 ++ net/batman-adv/netlink.c | 14 ++++++++++++-- net/batman-adv/types.h | 6 ++++++ 6 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/include/uapi/linux/batman_adv.h b/include/uapi/linux/batman_adv.h index 617c180f..dac57936 100644 --- a/include/uapi/linux/batman_adv.h +++ b/include/uapi/linux/batman_adv.h @@ -427,7 +427,8 @@ enum batadv_nl_attrs {

/** * @BATADV_ATTR_HOP_PENALTY: defines the penalty which will be applied - * to an originator message's tq-field on every hop. + * to an originator message's tq-field on every hop and/or per + * hard interface */ BATADV_ATTR_HOP_PENALTY,

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c index e87f19c8..5f7a5c04 100644 --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -1075,10 +1075,10 @@ static bool batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node, struct batadv_neigh_ifinfo *neigh_ifinfo; u8 total_count; u8 orig_eq_count, neigh_rq_count, neigh_rq_inv, tq_own; + unsigned int tq_iface_hop_penalty = BATADV_TQ_MAX_VALUE; unsigned int neigh_rq_inv_cube, neigh_rq_max_cube; unsigned int tq_asym_penalty, inv_asym_penalty; unsigned int combined_tq; - unsigned int tq_iface_penalty; bool ret = false;

/* find corresponding one hop neighbor */ @@ -1157,31 +1157,32 @@ static bool batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node, inv_asym_penalty = BATADV_TQ_MAX_VALUE * neigh_rq_inv_cube; inv_asym_penalty /= neigh_rq_max_cube; tq_asym_penalty = BATADV_TQ_MAX_VALUE - inv_asym_penalty; + tq_iface_hop_penalty -= atomic_read(&if_incoming->hop_penalty);

/* penalize if the OGM is forwarded on the same interface. WiFi * interfaces and other half duplex devices suffer from throughput * drops as they can't send and receive at the same time. */ - tq_iface_penalty = BATADV_TQ_MAX_VALUE; if (if_outgoing && if_incoming == if_outgoing && batadv_is_wifi_hardif(if_outgoing)) - tq_iface_penalty = batadv_hop_penalty(BATADV_TQ_MAX_VALUE, - bat_priv); + tq_iface_hop_penalty = batadv_hop_penalty(tq_iface_hop_penalty, + bat_priv);

combined_tq = batadv_ogm_packet->tq * tq_own * tq_asym_penalty * - tq_iface_penalty; + tq_iface_hop_penalty; combined_tq /= BATADV_TQ_MAX_VALUE * BATADV_TQ_MAX_VALUE * BATADV_TQ_MAX_VALUE; batadv_ogm_packet->tq = combined_tq;

batadv_dbg(BATADV_DBG_BATMAN, bat_priv, - "bidirectional: orig = %pM neigh = %pM => own_bcast = %2i, real recv = %2i, local tq: %3i, asym_penalty: %3i, iface_penalty: %3i, total tq: %3i, if_incoming = %s, if_outgoing = %s\n", + "bidirectional: orig = %pM neigh = %pM => own_bcast = %2i, real recv = %2i, local tq: %3i, asym_penalty: %3i, iface_hop_penalty: %3i, total tq: %3i, if_incoming = %s, if_outgoing = %s\n", orig_node->orig, orig_neigh_node->orig, total_count, - neigh_rq_count, tq_own, tq_asym_penalty, tq_iface_penalty, - batadv_ogm_packet->tq, if_incoming->net_dev->name, + neigh_rq_count, tq_own, tq_asym_penalty, + tq_iface_hop_penalty, batadv_ogm_packet->tq, + if_incoming->net_dev->name, if_outgoing ? if_outgoing->net_dev->name : "DEFAULT");

/* if link has the minimum required transmission quality diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index 18028b9f..1e84ab99 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -455,15 +455,17 @@ void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface) * @throughput: the current throughput * * Apply a penalty on the current throughput metric value based on the - * characteristic of the interface where the OGM has been received. The return - * value is computed as follows: + * characteristic of the interface where the OGM has been received. + * + * Initially the per hardif hop penalty is applied to the throughput. After + * that the return value is then computed as follows: * - throughput * 50% if the incoming and outgoing interface are the * same WiFi interface and the throughput is above * 1MBit/s * - throughput if the outgoing interface is the default * interface (i.e. this OGM is processed for the * internal table and not forwarded) - * - throughput * hop penalty otherwise + * - throughput * node hop penalty otherwise * * Return: the penalised throughput metric. */ @@ -472,9 +474,14 @@ static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv, struct batadv_hard_iface *if_outgoing, u32 throughput) { + int if_hop_penalty = atomic_read(&if_incoming->hop_penalty); int hop_penalty = atomic_read(&bat_priv->hop_penalty); int hop_penalty_max = BATADV_TQ_MAX_VALUE;

+ /* Apply per hardif hop penalty */ + throughput = throughput * (hop_penalty_max - if_hop_penalty) / + hop_penalty_max; + /* Don't apply hop penalty in default originator table. */ if (if_outgoing == BATADV_IF_DEFAULT) return throughput; diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 3a256af9..f8495ff2 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -939,6 +939,8 @@ batadv_hardif_add_interface(struct net_device *net_dev) if (batadv_is_wifi_hardif(hard_iface)) hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;

+ atomic_set(&hard_iface->hop_penalty, 0); + batadv_v_hardif_init(hard_iface);

batadv_check_known_mac_addr(hard_iface->net_dev); diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c index 02ed073f..d4bfc4c5 100644 --- a/net/batman-adv/netlink.c +++ b/net/batman-adv/netlink.c @@ -826,6 +826,10 @@ static int batadv_netlink_hardif_fill(struct sk_buff *msg, goto nla_put_failure; }

+ if (nla_put_u8(msg, BATADV_ATTR_HOP_PENALTY, + atomic_read(&hard_iface->hop_penalty))) + goto nla_put_failure; + #ifdef CONFIG_BATMAN_ADV_BATMAN_V if (nla_put_u32(msg, BATADV_ATTR_ELP_INTERVAL, atomic_read(&hard_iface->bat_v.elp_interval))) @@ -920,10 +924,16 @@ static int batadv_netlink_set_hardif(struct sk_buff *skb, { struct batadv_hard_iface *hard_iface = info->user_ptr[1]; struct batadv_priv *bat_priv = info->user_ptr[0]; - -#ifdef CONFIG_BATMAN_ADV_BATMAN_V struct nlattr *attr;

+ if (info->attrs[BATADV_ATTR_HOP_PENALTY]) { + attr = info->attrs[BATADV_ATTR_HOP_PENALTY]; + + atomic_set(&hard_iface->hop_penalty, nla_get_u8(attr)); + } + +#ifdef CONFIG_BATMAN_ADV_BATMAN_V + if (info->attrs[BATADV_ATTR_ELP_INTERVAL]) { attr = info->attrs[BATADV_ATTR_ELP_INTERVAL];

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index d152b8e8..f7b52426 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -208,6 +208,12 @@ struct batadv_hard_iface { /** @rcu: struct used for freeing in an RCU-safe manner */ struct rcu_head rcu;

+ /** + * @hop_penalty: penalty which will be applied to the tq-field + * of an OGM received via this interface + */ + atomic_t hop_penalty; + /** @bat_iv: per hard-interface B.A.T.M.A.N. IV data */ struct batadv_hard_iface_bat_iv bat_iv;