path: root/net/mac80211/mesh.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2008, 2009 open80211s Ltd.
 * Copyright (C) 2018 - 2019 Intel Corporation
 * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
 * 	       Javier Cardona <javier@cozybit.com>
 */

#include <linux/slab.h>
#include <asm/unaligned.h>
#include "ieee80211_i.h"
#include "mesh.h"
#include "driver-ops.h"

static int mesh_allocated;
static struct kmem_cache *rm_cache;

bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt)
{
	return (mgmt->u.action.u.mesh_action.action_code ==
			WLAN_MESH_ACTION_HWMP_PATH_SELECTION);
}

void ieee80211s_init(void)
{
	mesh_allocated = 1;
	rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
				     0, 0, NULL);
}

void ieee80211s_stop(void)
{
	if (!mesh_allocated)
		return;
	kmem_cache_destroy(rm_cache);
}

static void ieee80211_mesh_housekeeping_timer(struct timer_list *t)
{
	struct ieee80211_sub_if_data *sdata =
		from_timer(sdata, t, u.mesh.housekeeping_timer);
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

	set_bit(MESH_WORK_HOUSEKEEPING, &ifmsh->wrkq_flags);

	ieee80211_queue_work(&local->hw, &sdata->work);
}

/**
 * mesh_matches_local - check if the config of a mesh point matches ours
 *
 * @sdata: local mesh subif
 * @ie: information elements of a management frame from the mesh peer
 *
 * This function checks if the mesh configuration of a mesh point matches the
 * local mesh configuration, i.e. if both nodes belong to the same mesh network.
 */
bool mesh_matches_local(struct ieee80211_sub_if_data *sdata,
			struct ieee802_11_elems *ie)
{
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
	u32 basic_rates = 0;
	struct cfg80211_chan_def sta_chan_def;
	struct ieee80211_supported_band *sband;

	/*
	 * As support for each feature is added, check for matching
	 * - On mesh config capabilities
	 *   - Power Save Support En
	 *   - Sync support enabled
	 *   - Sync support active
	 *   - Sync support required from peer
	 *   - MDA enabled
	 * - Power management control on fc
	 */
	if (!(ifmsh->mesh_id_len == ie->mesh_id_len &&
	     memcmp(ifmsh->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&
	     (ifmsh->mesh_pp_id == ie->mesh_config->meshconf_psel) &&
	     (ifmsh->mesh_pm_id == ie->mesh_config->meshconf_pmetric) &&
	     (ifmsh->mesh_cc_id == ie->mesh_config->meshconf_congest) &&
	     (ifmsh->mesh_sp_id == ie->mesh_config->meshconf_synch) &&
	     (ifmsh->mesh_auth_id == ie->mesh_config->meshconf_auth)))
		return false;

	sband = ieee80211_get_sband(sdata);
	if (!sband)
		return false;

	ieee80211_sta_get_rates(sdata, ie, sband->band,
				&basic_rates);

	if (sdata->vif.bss_conf.basic_rates != basic_rates)
		return false;

	cfg80211_chandef_create(&sta_chan_def, sdata->vif.bss_conf.chandef.chan,
				NL80211_CHAN_NO_HT);
	ieee80211_chandef_ht_oper(ie->ht_operation, &sta_chan_def);
	ieee80211_chandef_vht_oper(&sdata->local->hw,
				   ie->vht_operation, ie->ht_operation,
				   &sta_chan_def);

	if (!cfg80211_chandef_compatible(&sdata->vif.bss_conf.chandef,
					 &sta_chan_def))
		return false;

	return true;
}

/**
 * mesh_peer_accepts_plinks - check if an mp is willing to establish peer links
 *
 * @ie: information elements of a management frame from the mesh peer
 */
bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie)
{
	return (ie->mesh_config->meshconf_cap &
			IEEE80211_MESHCONF_CAPAB_ACCEPT_PLINKS) != 0;
}

/**
 * mesh_accept_plinks_update - update accepting_plink in local mesh beacons
 *
 * @sdata: mesh interface in which mesh beacons are going to be updated
 *
 * Returns: beacon changed flag if the beacon content changed.
 */
u32 mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)
{
	bool free_plinks;
	u32 changed = 0;

	/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
	 * the mesh interface might be able to establish plinks with peers that
	 * are already on the table but are not on PLINK_ESTAB state. However,
	 * in general the mesh interface is not accepting peer link requests
	 * from new peers, and that must be reflected in the beacon
	 */
	free_plinks = mesh_plink_availables(sdata);

	if (free_plinks != sdata->u.mesh.accepting_plinks) {
		sdata->u.mesh.accepting_plinks = free_plinks;
		changed = BSS_CHANGED_BEACON;
	}

	return changed;
}

/*
 * mesh_sta_cleanup - clean up any mesh sta state
 *
 * @sta: mesh sta to clean up.
 */
void mesh_sta_cleanup(struct sta_info *sta)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	u32 changed = mesh_plink_deactivate(sta);

	if (changed)
		ieee80211_mbss_info_change_notify(sdata, changed);
}

int mesh_rmc_init(struct ieee80211_sub_if_data *sdata)
{
	int i;

	sdata->u.mesh.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);
	if (!sdata->u.mesh.rmc)
		return -ENOMEM;
	sdata->u.mesh.rmc->idx_mask = RMC_BUCKETS - 1;
	for (i = 0; i < RMC_BUCKETS; i++)
		INIT_HLIST_HEAD(&sdata->u.mesh.rmc->bucket[i]);
	return 0;
}

void mesh_rmc_free(struct ieee80211_sub_if_data *sdata)
{
	struct mesh_rmc *rmc = sdata->u.mesh.rmc;
	struct rmc_entry *p;
	struct hlist_node *n;
	int i;

	if (!sdata->u.mesh.rmc)
		return;

	for (i = 0; i < RMC_BUCKETS; i++) {
		hlist_for_each_entry_safe(p, n, &rmc->bucket[i], list) {
			hlist_del(&p->list);
			kmem_cache_free(rm_cache, p);
		}
	}

	kfree(rmc);
	sdata->u.mesh.rmc = NULL;
}

/**
 * mesh_rmc_check - Check frame in recent multicast cache and add if absent.
 *
 * @sdata:	interface
 * @sa:		source address
 * @mesh_hdr:	mesh_header
 *
 * Returns: 0 if the frame is not in the cache, nonzero otherwise.
 *
 * Checks using the source address and the mesh sequence number if we have
 * received this frame lately. If the frame is not in the cache, it is added to
 * it.
 */
int mesh_rmc_check(struct ieee80211_sub_if_data *sdata,
		   const u8 *sa, struct ieee80211s_hdr *mesh_hdr)
{
	struct mesh_rmc *rmc = sdata->u.mesh.rmc;
	u32 seqnum = 0;
	int entries = 0;
	u8 idx;
	struct rmc_entry *p;
	struct hlist_node *n;

	if (!rmc)
		return -1;

	/* Don't care about endianness since only match matters */
	memcpy(&seqnum, &mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));
	idx = le32_to_cpu(mesh_hdr->seqnum) & rmc->idx_mask;
	hlist_for_each_entry_safe(p, n, &rmc->bucket[idx], list) {
		++entries;
		if (time_after(jiffies, p->exp_time) ||
		    entries == RMC_QUEUE_MAX_LEN) {
			hlist_del(&p->list);
			kmem_cache_free(rm_cache, p);
			--entries;
		} else if ((seqnum == p->seqnum) && ether_addr_equal(sa, p->sa))
			return -1;
	}

	p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);
	if (!p)
		return 0;

	p->seqnum = seqnum;
	p->exp_time = jiffies + RMC_TIMEOUT;
	memcpy(p->sa, sa, ETH_ALEN);
	hlist_add_head(&p->l