path: root/net/mac80211/mesh_pathtbl.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2008, 2009 open80211s Ltd.
 * Copyright (C) 2023 Intel Corporation
 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <net/mac80211.h>
#include "wme.h"
#include "ieee80211_i.h"
#include "mesh.h"
#include <linux/rhashtable.h>

static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);

static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
{
	/* Use last four bytes of hw addr as hash index */
	return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
}

static const struct rhashtable_params mesh_rht_params = {
	.nelem_hint = 2,
	.automatic_shrinking = true,
	.key_len = ETH_ALEN,
	.key_offset = offsetof(struct mesh_path, dst),
	.head_offset = offsetof(struct mesh_path, rhash),
	.hashfn = mesh_table_hash,
};

static const struct rhashtable_params fast_tx_rht_params = {
	.nelem_hint = 10,
	.automatic_shrinking = true,
	.key_len = ETH_ALEN,
	.key_offset = offsetof(struct ieee80211_mesh_fast_tx, addr_key),
	.head_offset = offsetof(struct ieee80211_mesh_fast_tx, rhash),
	.hashfn = mesh_table_hash,
};

static void __mesh_fast_tx_entry_free(void *ptr, void *tblptr)
{
	struct ieee80211_mesh_fast_tx *entry = ptr;

	kfree_rcu(entry, fast_tx.rcu_head);
}

static void mesh_fast_tx_deinit(struct ieee80211_sub_if_data *sdata)
{
	struct mesh_tx_cache *cache;

	cache = &sdata->u.mesh.tx_cache;
	rhashtable_free_and_destroy(&cache->rht,
				    __mesh_fast_tx_entry_free, NULL);
}

static void mesh_fast_tx_init(struct ieee80211_sub_if_data *sdata)
{
	struct mesh_tx_cache *cache;

	cache = &sdata->u.mesh.tx_cache;
	rhashtable_init(&cache->rht, &fast_tx_rht_params);
	INIT_HLIST_HEAD(&cache->walk_head);
	spin_lock_init(&cache->walk_lock);
}

static inline bool mpath_expired(struct mesh_path *mpath)
{
	return (mpath->flags & MESH_PATH_ACTIVE) &&
	       time_after(jiffies, mpath->exp_time) &&
	       !(mpath->flags & MESH_PATH_FIXED);
}

static void mesh_path_rht_free(void *ptr, void *tblptr)
{
	struct mesh_path *mpath = ptr;
	struct mesh_table *tbl = tblptr;

	mesh_path_free_rcu(tbl, mpath);
}

static void mesh_table_init(struct mesh_table *tbl)
{
	INIT_HLIST_HEAD(&tbl->known_gates);
	INIT_HLIST_HEAD(&tbl->walk_head);
	atomic_set(&tbl->entries,  0);
	spin_lock_init(&tbl->gates_lock);
	spin_lock_init(&tbl->walk_lock);

	/* rhashtable_init() may fail only in case of wrong
	 * mesh_rht_params
	 */
	WARN_ON(rhashtable_init(&tbl->rhead, &mesh_rht_params));
}

static void mesh_table_free(struct mesh_table *tbl)
{
	rhashtable_free_and_destroy(&tbl->rhead,
				    mesh_path_rht_free, tbl);
}

/**
 * mesh_path_assign_nexthop - update mesh path next hop
 *
 * @mpath: mesh path to update
 * @sta: next hop to assign
 *
 * Locking: mpath->state_lock must be held when calling this function
 */
void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
{
	struct sk_buff *skb;
	struct ieee80211_hdr *hdr;
	unsigned long flags;

	rcu_assign_pointer(mpath->next_hop, sta);

	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
	skb_queue_walk(&mpath->frame_queue, skb) {
		hdr = (struct ieee80211_hdr *) skb->data;
		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
		memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
		ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
	}

	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
}

static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
			     struct mesh_path *gate_mpath)
{
	struct ieee80211_hdr *hdr;
	struct ieee80211s_hdr *mshdr;
	int mesh_hdrlen, hdrlen;
	char *next_hop;

	hdr = (struct ieee80211_hdr *) skb->data;
	hdrlen = ieee80211_hdrlen(hdr->frame_control);
	mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);

	if (!(mshdr->flags & MESH_FLAGS_AE)) {
		/* size of the fixed part of the mesh header */
		mesh_hdrlen = 6;

		/* make room for the two extended addresses */</