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Commit 2f1dfbe1 authored by Antonio Quartulli's avatar Antonio Quartulli
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batman-adv: Distributed ARP Table - implement local storage



Since batman-adv cannot inter-operate with the host ARP table, this patch
introduces a batman-adv private storage for ARP entries exchanged within DAT.
This storage will represent the node local cache in the DAT protocol.

Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent 785ea114
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+15 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@
#include "vis.h"
#include "icmp_socket.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"

static struct dentry *batadv_debugfs;

@@ -280,6 +281,18 @@ static int batadv_bla_backbone_table_open(struct inode *inode,

#endif

/**
 * batadv_dat_cache_open - Prepare file handler for reads from dat_chache
 * @inode: inode which was opened
 * @file: file handle to be initialized
 */
static int batadv_dat_cache_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;
	return single_open(file, batadv_dat_cache_seq_print_text, net_dev);
}


static int batadv_transtable_local_open(struct inode *inode, struct file *file)
{
	struct net_device *net_dev = (struct net_device *)inode->i_private;
@@ -319,6 +332,7 @@ static BATADV_DEBUGINFO(bla_claim_table, S_IRUGO, batadv_bla_claim_table_open);
static BATADV_DEBUGINFO(bla_backbone_table, S_IRUGO,
			batadv_bla_backbone_table_open);
#endif
static BATADV_DEBUGINFO(dat_cache, S_IRUGO, batadv_dat_cache_open);
static BATADV_DEBUGINFO(transtable_local, S_IRUGO,
			batadv_transtable_local_open);
static BATADV_DEBUGINFO(vis_data, S_IRUGO, batadv_vis_data_open);
@@ -331,6 +345,7 @@ static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
	&batadv_debuginfo_bla_claim_table,
	&batadv_debuginfo_bla_backbone_table,
#endif
	&batadv_debuginfo_dat_cache,
	&batadv_debuginfo_transtable_local,
	&batadv_debuginfo_vis_data,
	NULL,
+296 −0
Original line number Diff line number Diff line
@@ -28,6 +28,119 @@
#include "types.h"
#include "unicast.h"

static void batadv_dat_purge(struct work_struct *work);

/**
 * batadv_dat_start_timer - initialise the DAT periodic worker
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_dat_start_timer(struct batadv_priv *bat_priv)
{
	INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
	queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work,
			   msecs_to_jiffies(10000));
}

/**
 * batadv_dat_entry_free_ref - decrements the dat_entry refcounter and possibly
 * free it
 * @dat_entry: the oentry to free
 */
static void batadv_dat_entry_free_ref(struct batadv_dat_entry *dat_entry)
{
	if (atomic_dec_and_test(&dat_entry->refcount))
		kfree_rcu(dat_entry, rcu);
}

/**
 * batadv_dat_to_purge - checks whether a dat_entry has to be purged or not
 * @dat_entry: the entry to check
 *
 * Returns true if the entry has to be purged now, false otherwise
 */
static bool batadv_dat_to_purge(struct batadv_dat_entry *dat_entry)
{
	return batadv_has_timed_out(dat_entry->last_update,
				    BATADV_DAT_ENTRY_TIMEOUT);
}

/**
 * __batadv_dat_purge - delete entries from the DAT local storage
 * @bat_priv: the bat priv with all the soft interface information
 * @to_purge: function in charge to decide whether an entry has to be purged or
 *	      not. This function takes the dat_entry as argument and has to
 *	      returns a boolean value: true is the entry has to be deleted,
 *	      false otherwise
 *
 * Loops over each entry in the DAT local storage and delete it if and only if
 * the to_purge function passed as argument returns true
 */
static void __batadv_dat_purge(struct batadv_priv *bat_priv,
			       bool (*to_purge)(struct batadv_dat_entry *))
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_dat_entry *dat_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	uint32_t i;

	if (!bat_priv->dat.hash)
		return;

	for (i = 0; i < bat_priv->dat.hash->size; i++) {
		head = &bat_priv->dat.hash->table[i];
		list_lock = &bat_priv->dat.hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(dat_entry, node, node_tmp, head,
					  hash_entry) {
			/* if an helper function has been passed as parameter,
			 * ask it if the entry has to be purged or not
			 */
			if (to_purge && !to_purge(dat_entry))
				continue;

			hlist_del_rcu(node);
			batadv_dat_entry_free_ref(dat_entry);
		}
		spin_unlock_bh(list_lock);
	}
}

/**
 * batadv_dat_purge - periodic task that deletes old entries from the local DAT
 * hash table
 * @work: kernel work struct
 */
static void batadv_dat_purge(struct work_struct *work)
{
	struct delayed_work *delayed_work;
	struct batadv_priv_dat *priv_dat;
	struct batadv_priv *bat_priv;

	delayed_work = container_of(work, struct delayed_work, work);
	priv_dat = container_of(delayed_work, struct batadv_priv_dat, work);
	bat_priv = container_of(priv_dat, struct batadv_priv, dat);

	__batadv_dat_purge(bat_priv, batadv_dat_to_purge);
	batadv_dat_start_timer(bat_priv);
}

/**
 * batadv_compare_dat - comparing function used in the local DAT hash table
 * @node: node in the local table
 * @data2: second object to compare the node to
 *
 * Returns 1 if the two entry are the same, 0 otherwise
 */
static int batadv_compare_dat(const struct hlist_node *node, const void *data2)
{
	const void *data1 = container_of(node, struct batadv_dat_entry,
					 hash_entry);

	return (memcmp(data1, data2, sizeof(__be32)) == 0 ? 1 : 0);
}

/**
 * batadv_hash_dat - compute the hash value for an IP address
 * @data: data to hash
@@ -54,6 +167,96 @@ static uint32_t batadv_hash_dat(const void *data, uint32_t size)
	return hash % size;
}

/**
 * batadv_dat_entry_hash_find - looks for a given dat_entry in the local hash
 * table
 * @bat_priv: the bat priv with all the soft interface information
 * @ip: search key
 *
 * Returns the dat_entry if found, NULL otherwise
 */
static struct batadv_dat_entry *
batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct batadv_dat_entry *dat_entry, *dat_entry_tmp = NULL;
	struct batadv_hashtable *hash = bat_priv->dat.hash;
	uint32_t index;

	if (!hash)
		return NULL;

	index = batadv_hash_dat(&ip, hash->size);
	head = &hash->table[index];

	rcu_read_lock();
	hlist_for_each_entry_rcu(dat_entry, node, head, hash_entry) {
		if (dat_entry->ip != ip)
			continue;

		if (!atomic_inc_not_zero(&dat_entry->refcount))
			continue;

		dat_entry_tmp = dat_entry;
		break;
	}
	rcu_read_unlock();

	return dat_entry_tmp;
}

/**
 * batadv_dat_entry_add - add a new dat entry or update it if already exists
 * @bat_priv: the bat priv with all the soft interface information
 * @ip: ipv4 to add/edit
 * @mac_addr: mac address to assign to the given ipv4
 */
static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
				 uint8_t *mac_addr)
{
	struct batadv_dat_entry *dat_entry;
	int hash_added;

	dat_entry = batadv_dat_entry_hash_find(bat_priv, ip);
	/* if this entry is already known, just update it */
	if (dat_entry) {
		if (!batadv_compare_eth(dat_entry->mac_addr, mac_addr))
			memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
		dat_entry->last_update = jiffies;
		batadv_dbg(BATADV_DBG_DAT, bat_priv,
			   "Entry updated: %pI4 %pM\n", &dat_entry->ip,
			   dat_entry->mac_addr);
		goto out;
	}

	dat_entry = kmalloc(sizeof(*dat_entry), GFP_ATOMIC);
	if (!dat_entry)
		goto out;

	dat_entry->ip = ip;
	memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
	dat_entry->last_update = jiffies;
	atomic_set(&dat_entry->refcount, 2);

	hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat,
				     batadv_hash_dat, &dat_entry->ip,
				     &dat_entry->hash_entry);

	if (unlikely(hash_added != 0)) {
		/* remove the reference for the hash */
		batadv_dat_entry_free_ref(dat_entry);
		goto out;
	}

	batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM\n",
		   &dat_entry->ip, dat_entry->mac_addr);

out:
	if (dat_entry)
		batadv_dat_entry_free_ref(dat_entry);
}

/**
 * batadv_is_orig_node_eligible - check whether a node can be a DHT candidate
 * @res: the array with the already selected candidates
@@ -268,3 +471,96 @@ static bool batadv_dat_send_data(struct batadv_priv *bat_priv,
	kfree(cand);
	return ret;
}

/**
 * batadv_dat_hash_free - free the local DAT hash table
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_dat_hash_free(struct batadv_priv *bat_priv)
{
	__batadv_dat_purge(bat_priv, NULL);

	batadv_hash_destroy(bat_priv->dat.hash);

	bat_priv->dat.hash = NULL;
}

/**
 * batadv_dat_init - initialise the DAT internals
 * @bat_priv: the bat priv with all the soft interface information
 */
int batadv_dat_init(struct batadv_priv *bat_priv)
{
	if (bat_priv->dat.hash)
		return 0;

	bat_priv->dat.hash = batadv_hash_new(1024);

	if (!bat_priv->dat.hash)
		return -ENOMEM;

	batadv_dat_start_timer(bat_priv);

	return 0;
}

/**
 * batadv_dat_free - free the DAT internals
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_dat_free(struct batadv_priv *bat_priv)
{
	cancel_delayed_work_sync(&bat_priv->dat.work);

	batadv_dat_hash_free(bat_priv);
}

/**
 * batadv_dat_cache_seq_print_text - print the local DAT hash table
 * @seq: seq file to print on
 * @offset: not used
 */
int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
	struct batadv_hashtable *hash = bat_priv->dat.hash;
	struct batadv_dat_entry *dat_entry;
	struct batadv_hard_iface *primary_if;
	struct hlist_node *node;
	struct hlist_head *head;
	unsigned long last_seen_jiffies;
	int last_seen_msecs, last_seen_secs, last_seen_mins;
	uint32_t i;

	primary_if = batadv_seq_print_text_primary_if_get(seq);
	if (!primary_if)
		goto out;

	seq_printf(seq, "Distributed ARP Table (%s):\n", net_dev->name);
	seq_printf(seq, "          %-7s          %-13s %5s\n", "IPv4", "MAC",
		   "last-seen");

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(dat_entry, node, head, hash_entry) {
			last_seen_jiffies = jiffies - dat_entry->last_update;
			last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
			last_seen_mins = last_seen_msecs / 60000;
			last_seen_msecs = last_seen_msecs % 60000;
			last_seen_secs = last_seen_msecs / 1000;

			seq_printf(seq, " * %15pI4 %14pM %6i:%02i\n",
				   &dat_entry->ip, dat_entry->mac_addr,
				   last_seen_mins, last_seen_secs);
		}
		rcu_read_unlock();
	}

out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return 0;
}
+4 −0
Original line number Diff line number Diff line
@@ -55,4 +55,8 @@ batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
	bat_priv->dat.addr = (batadv_dat_addr_t)addr;
}

int batadv_dat_init(struct batadv_priv *bat_priv);
void batadv_dat_free(struct batadv_priv *bat_priv);
int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset);

#endif /* _NET_BATMAN_ADV_ARP_H_ */
+7 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@
#include "hard-interface.h"
#include "gateway_client.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "vis.h"
#include "hash.h"
#include "bat_algo.h"
@@ -128,6 +129,10 @@ int batadv_mesh_init(struct net_device *soft_iface)
	if (ret < 0)
		goto err;

	ret = batadv_dat_init(bat_priv);
	if (ret < 0)
		goto err;

	atomic_set(&bat_priv->gw.reselect, 0);
	atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);

@@ -155,6 +160,8 @@ void batadv_mesh_free(struct net_device *soft_iface)

	batadv_bla_free(bat_priv);

	batadv_dat_free(bat_priv);

	free_percpu(bat_priv->bat_counters);

	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@
#define BATADV_TT_LOCAL_TIMEOUT 3600000 /* in milliseconds */
#define BATADV_TT_CLIENT_ROAM_TIMEOUT 600000 /* in milliseconds */
#define BATADV_TT_CLIENT_TEMP_TIMEOUT 600000 /* in milliseconds */
#define BATADV_DAT_ENTRY_TIMEOUT (5*60000) /* 5 mins in milliseconds */
/* sliding packet range of received originator messages in sequence numbers
 * (should be a multiple of our word size)
 */
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