Commit 2f1dfbe1 authored by Antonio Quartulli's avatar Antonio Quartulli

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
......@@ -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,
......
......@@ -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;
}
......@@ -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_ */
......@@ -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);
......
......@@ -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)
*/
......
......@@ -249,9 +249,13 @@ struct batadv_priv_vis {
/**
* struct batadv_priv_dat - per mesh interface DAT private data
* @addr: node DAT address
* @hash: hashtable representing the local ARP cache
* @work: work queue callback item for cache purging
*/
struct batadv_priv_dat {
batadv_dat_addr_t addr;
struct batadv_hashtable *hash;
struct delayed_work work;
};
struct batadv_priv {
......@@ -464,6 +468,25 @@ struct batadv_algo_ops {
void (*bat_ogm_emit)(struct batadv_forw_packet *forw_packet);
};
/**
* struct batadv_dat_entry - it is a single entry of batman-adv ARP backend. It
* is used to stored ARP entries needed for the global DAT cache
* @ip: the IPv4 corresponding to this DAT/ARP entry
* @mac_addr: the MAC address associated to the stored IPv4
* @last_update: time in jiffies when this entry was refreshed last time
* @hash_entry: hlist node for batadv_priv_dat::hash
* @refcount: number of contexts the object is used
* @rcu: struct used for freeing in an RCU-safe manner
*/
struct batadv_dat_entry {
__be32 ip;
uint8_t mac_addr[ETH_ALEN];
unsigned long last_update;
struct hlist_node hash_entry;
atomic_t refcount;
struct rcu_head rcu;
};
/**
* struct batadv_dat_candidate - candidate destination for DAT operations
* @type: the type of the selected candidate. It can one of the following:
......
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