usteer: Initial import

Signed-off-by: Felix Fietkau <nbd@nbd.name>
2018-03-21 16:40:05 +01:00
commit d10731f806
23 changed files with 4512 additions and 0 deletions
--- a/policy.c
+++ b/policy.c
@@ -0,0 +1,436 @@
+/*
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License.
+ *
+ *   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, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ *
+ *   Copyright (C) 2020 embedd.ch 
+ *   Copyright (C) 2020 Felix Fietkau <nbd@nbd.name> 
+ *   Copyright (C) 2020 John Crispin <john@phrozen.org> 
+ */
+
+#include "usteer.h"
+#include "node.h"
+
+static bool
+below_assoc_threshold(struct sta_info *si_cur, struct sta_info *si_new)
+{
+	int n_assoc_cur = si_cur->node->n_assoc;
+	int n_assoc_new = si_new->node->n_assoc;
+	bool ref_5g = si_cur->node->freq > 4000;
+	bool node_5g = si_new->node->freq > 4000;
+
+	if (ref_5g && !node_5g)
+		n_assoc_new += config.band_steering_threshold;
+	else if (!ref_5g && node_5g)
+		n_assoc_cur += config.band_steering_threshold;
+
+	n_assoc_new += config.load_balancing_threshold;
+
+	if (n_assoc_new > n_assoc_cur) {
+		MSG_T_STA("band_steering_threshold,load_balancing_threshold",
+			si_cur->sta->addr, "exeeded (bs=%u, lb=%u)\n",
+			config.band_steering_threshold,
+			config.load_balancing_threshold);
+	}
+	return n_assoc_new <= n_assoc_cur;
+}
+
+static bool
+better_signal_strength(struct sta_info *si_cur, struct sta_info *si_new)
+{
+	const bool is_better = si_new->signal - si_cur->signal
+				> (int) config.signal_diff_threshold;
+
+	if (!config.signal_diff_threshold)
+		return false;
+
+	if (is_better) {
+		MSG_T_STA("signal_diff_threshold", si_cur->sta->addr,
+			"exceeded (config=%i) (real=%i)\n",
+			config.signal_diff_threshold,
+			si_new->signal - si_cur->signal);
+	}
+	return is_better;
+}
+
+static bool
+below_load_threshold(struct sta_info *si)
+{
+	return si->node->n_assoc >= config.load_kick_min_clients &&
+	       si->node->load > config.load_kick_threshold;
+}
+
+static bool
+has_better_load(struct sta_info *si_cur, struct sta_info *si_new)
+{
+	return !below_load_threshold(si_cur) && below_load_threshold(si_new);
+}
+
+static bool
+below_max_assoc(struct sta_info *si)
+{
+	struct usteer_node *node = si->node;
+
+	return !node->max_assoc || node->n_assoc < node->max_assoc;
+}
+
+static bool
+is_better_candidate(struct sta_info *si_cur, struct sta_info *si_new)
+{
+	if (!below_max_assoc(si_new))
+		return false;
+
+	return below_assoc_threshold(si_cur, si_new) ||
+	       better_signal_strength(si_cur, si_new) ||
+	       has_better_load(si_cur, si_new);
+}
+
+static struct sta_info *
+find_better_candidate(struct sta_info *si_ref)
+{
+	struct sta_info *si;
+	struct sta *sta = si_ref->sta;
+
+	list_for_each_entry(si, &sta->nodes, list) {
+		if (si == si_ref)
+			continue;
+
+		if (current_time - si->seen > config.seen_policy_timeout) {
+			MSG_T_STA("seen_policy_timeout", si->sta->addr,
+				"timeout exceeded (%u)\n", config.seen_policy_timeout);
+			continue;
+		}
+
+		if (strcmp(si->node->ssid, si_ref->node->ssid) != 0)
+			continue;
+
+		if (is_better_candidate(si_ref, si) &&
+		    !is_better_candidate(si, si_ref))
+			return si;
+	}
+	return NULL;
+}
+
+static int
+snr_to_signal(struct usteer_node *node, int snr)
+{
+	int noise = -95;
+
+	if (snr < 0)
+		return snr;
+
+	if (node->noise)
+		noise = node->noise;
+
+	return noise + snr;
+}
+
+bool
+usteer_check_request(struct sta_info *si, enum usteer_event_type type)
+{
+	struct sta_info *si_new;
+	int min_signal;
+
+	if (type == EVENT_TYPE_ASSOC)
+		return true;
+
+	if (si->stats[type].blocked_cur >= config.max_retry_band) {
+		MSG_T_STA("max_retry_band", si->sta->addr,
+			"max retry (%u) exceeded\n", config.max_retry_band);
+		return true;
+	}
+
+	min_signal = snr_to_signal(si->node, config.min_connect_snr);
+	if (si->signal < min_signal) {
+		if (type != EVENT_TYPE_PROBE || config.debug_level >= MSG_DEBUG)
+			MSG(VERBOSE, "Ignoring %s request from "MAC_ADDR_FMT" due to low signal (%d < %d)\n",
+			    event_types[type], MAC_ADDR_DATA(si->sta->addr),
+			    si->signal, min_signal);
+		MSG_T_STA("min_connect_snr", si->sta->addr,
+			"snr to low (config=%i) (real=%i)\n",
+			min_signal, si->signal);
+		return false;
+	}
+
+	if (current_time - si->created < config.initial_connect_delay) {
+		if (type != EVENT_TYPE_PROBE || config.debug_level >= MSG_DEBUG)
+			MSG(VERBOSE, "Ignoring %s request from "MAC_ADDR_FMT" during initial connect delay\n",
+			    event_types[type], MAC_ADDR_DATA(si->sta->addr));
+		MSG_T_STA("initial_connect_delay", si->sta->addr,
+			"is below delay (%u)\n", config.initial_connect_delay);
+		return false;
+	}
+
+	si_new = find_better_candidate(si);
+	if (!si_new)
+		return true;
+
+	if (type != EVENT_TYPE_PROBE || config.debug_level >= MSG_DEBUG)
+		MSG(VERBOSE, "Ignoring %s request from "MAC_ADDR_FMT", "
+			"node (local/remote): %s/%s, "
+			"signal=%d/%d, n_assoc=%d/%d\n", event_types[type],
+			MAC_ADDR_DATA(si->sta->addr),
+			usteer_node_name(si->node), usteer_node_name(si_new->node),
+			si->signal, si_new->signal,
+			si->node->n_assoc, si_new->node->n_assoc);
+
+	return false;
+}
+
+static bool
+is_more_kickable(struct sta_info *si_cur, struct sta_info *si_new)
+{
+	if (!si_cur)
+		return true;
+
+	if (si_new->kick_count > si_cur->kick_count)
+		return false;
+
+	return si_cur->signal > si_new->signal;
+}
+
+static void
+usteer_roam_set_state(struct sta_info *si, enum roam_trigger_state state)
+{
+	static const char * const state_names[] = {
+#define _S(n) [ROAM_TRIGGER_##n] = #n,
+		__roam_trigger_states
+#undef _S
+	};
+
+	si->roam_event = current_time;
+
+	if (si->roam_state == state) {
+		if (si->roam_state == ROAM_TRIGGER_IDLE) {
+			si->roam_tries = 0;
+			return;
+		}
+
+		si->roam_tries++;
+	} else {
+		si->roam_tries = 0;
+	}
+
+	si->roam_state = state;
+
+	MSG(VERBOSE, "Roam trigger SM for client "MAC_ADDR_FMT": state=%s, tries=%d, signal=%d\n",
+	    MAC_ADDR_DATA(si->sta->addr), state_names[state], si->roam_tries, si->signal);
+}
+
+static bool
+usteer_roam_trigger_sm(struct sta_info *si)
+{
+	struct sta_info *si_new;
+	int min_signal;
+
+	min_signal = snr_to_signal(si->node, config.roam_trigger_snr);
+
+	switch (si->roam_state) {
+	case ROAM_TRIGGER_SCAN:
+		if (current_time - si->roam_event < config.roam_scan_interval)
+			break;
+
+		if (find_better_candidate(si) ||
+		    si->roam_scan_done > si->roam_event) {
+			usteer_roam_set_state(si, ROAM_TRIGGER_SCAN_DONE);
+			break;
+		}
+
+		if (config.roam_scan_tries &&
+		    si->roam_tries >= config.roam_scan_tries) {
+			usteer_roam_set_state(si, ROAM_TRIGGER_WAIT_KICK);
+			break;
+		}
+
+		usteer_ubus_trigger_client_scan(si);
+		usteer_roam_set_state(si, ROAM_TRIGGER_SCAN);
+		break;
+
+	case ROAM_TRIGGER_IDLE:
+		if (find_better_candidate(si)) {
+			usteer_roam_set_state(si, ROAM_TRIGGER_SCAN_DONE);
+			break;
+		}
+
+		usteer_roam_set_state(si, ROAM_TRIGGER_SCAN);
+		break;
+
+	case ROAM_TRIGGER_SCAN_DONE:
+		/* Check for stale scan results, kick back to SCAN state if necessary */
+		if (current_time - si->roam_scan_done > 2 * config.roam_scan_interval) {
+			usteer_roam_set_state(si, ROAM_TRIGGER_SCAN);
+			break;
+		}
+
+		si_new = find_better_candidate(si);
+		if (!si_new)
+			break;
+
+		usteer_roam_set_state(si, ROAM_TRIGGER_WAIT_KICK);
+		break;
+
+	case ROAM_TRIGGER_WAIT_KICK:
+		if (si->signal > min_signal)
+			break;
+
+		usteer_roam_set_state(si, ROAM_TRIGGER_NOTIFY_KICK);
+		usteer_ubus_notify_client_disassoc(si);
+		break;
+	case ROAM_TRIGGER_NOTIFY_KICK:
+		if (current_time - si->roam_event < config.roam_kick_delay * 100)
+			break;
+
+		usteer_roam_set_state(si, ROAM_TRIGGER_KICK);
+		break;
+	case ROAM_TRIGGER_KICK:
+		usteer_ubus_kick_client(si);
+		usteer_roam_set_state(si, ROAM_TRIGGER_IDLE);
+		return true;
+	}
+
+	return false;
+}
+
+static void
+usteer_local_node_roam_check(struct usteer_local_node *ln)
+{
+	struct sta_info *si;
+	int min_signal;
+
+	if (config.roam_scan_snr)
+		min_signal = config.roam_scan_snr;
+	else if (config.roam_trigger_snr)
+		min_signal = config.roam_trigger_snr;
+	else
+		return;
+
+	usteer_update_time();
+	min_signal = snr_to_signal(&ln->node, min_signal);
+
+	list_for_each_entry(si, &ln->node.sta_info, node_list) {
+		if (!si->connected || si->signal >= min_signal ||
+		    current_time - si->roam_kick < config.roam_trigger_interval) {
+			usteer_roam_set_state(si, ROAM_TRIGGER_IDLE);
+			continue;
+		}
+
+		/*
+		 * If the state machine kicked a client, other clients should wait
+		 * until the next turn
+		 */
+		if (usteer_roam_trigger_sm(si))
+			return;
+	}
+}
+
+static void
+usteer_local_node_snr_kick(struct usteer_local_node *ln)
+{
+	struct sta_info *si;
+	int min_signal;
+
+	if (!config.min_snr)
+		return;
+
+	min_signal = snr_to_signal(&ln->node, config.min_snr);
+
+	list_for_each_entry(si, &ln->node.sta_info, node_list) {
+		if (!si->connected)
+			continue;
+
+		if (si->signal >= min_signal)
+			continue;
+
+		si->kick_count++;
+
+		MSG(VERBOSE, "Kicking client "MAC_ADDR_FMT" due to low SNR, signal=%d\n",
+			MAC_ADDR_DATA(si->sta->addr), si->signal);
+
+		usteer_ubus_kick_client(si);
+		return;
+	}
+}
+
+void
+usteer_local_node_kick(struct usteer_local_node *ln)
+{
+	struct usteer_node *node = &ln->node;
+	struct sta_info *kick1 = NULL, *kick2 = NULL;
+	struct sta_info *candidate = NULL;
+	struct sta_info *si;
+
+	usteer_local_node_roam_check(ln);
+	usteer_local_node_snr_kick(ln);
+
+	if (!config.load_kick_enabled || !config.load_kick_threshold ||
+	    !config.load_kick_delay)
+		return;
+
+	if (node->load < config.load_kick_threshold) {
+		MSG_T("load_kick_threshold",
+			"is below load for this node (config=%i) (real=%i)\n",
+			config.load_kick_threshold, node->load);
+		ln->load_thr_count = 0;
+		return;
+	}
+
+	if (++ln->load_thr_count <=
+	    DIV_ROUND_UP(config.load_kick_delay, config.local_sta_update)) {
+		MSG_T("load_kick_delay", "delay kicking (config=%i)\n",
+			config.load_kick_delay);
+		return;
+	}
+
+	MSG(VERBOSE, "AP load threshold exceeded on %s (%d), try to kick a client\n",
+	    usteer_node_name(node), node->load);
+
+	ln->load_thr_count = 0;
+	if (node->n_assoc < config.load_kick_min_clients) {
+		MSG_T("load_kick_min_clients",
+			"min limit reached, stop kicking clients on this node "
+			"(n_assoc=%i) (config=%i)\n",
+			node->n_assoc, config.load_kick_min_clients);
+		return;
+	}
+
+	list_for_each_entry(si, &ln->node.sta_info, node_list) {
+		struct sta_info *tmp;
+
+		if (!si->connected)
+			continue;
+
+		if (is_more_kickable(kick1, si))
+			kick1 = si;
+
+		tmp = find_better_candidate(si);
+		if (!tmp)
+			continue;
+
+		if (is_more_kickable(kick2, si)) {
+			kick2 = si;
+			candidate = tmp;
+		}
+	}
+
+	if (!kick1)
+		return;
+
+	if (kick2)
+		kick1 = kick2;
+
+	MSG(VERBOSE, "Kicking client "MAC_ADDR_FMT", signal=%d, better_candidate=%s\n",
+	    MAC_ADDR_DATA(kick1->sta->addr), kick1->signal,
+		candidate ? usteer_node_name(candidate->node) : "(none)");
+
+	kick1->kick_count++;
+	usteer_ubus_kick_client(kick1);
+}