| /* Copyright (C) 2011-2012 B.A.T.M.A.N. contributors: |
| * |
| * Antonio Quartulli |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of version 2 of the GNU General Public |
| * License as published by the Free Software Foundation. |
| * |
| * 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., 51 Franklin Street, Fifth Floor, Boston, MA |
| * 02110-1301, USA |
| */ |
| |
| #include <linux/if_ether.h> |
| #include <linux/if_arp.h> |
| |
| #include "main.h" |
| #include "distributed-arp-table.h" |
| #include "hard-interface.h" |
| #include "originator.h" |
| #include "send.h" |
| #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 |
| * @size: size of the hash table |
| * |
| * Returns the selected index in the hash table for the given data |
| */ |
| static uint32_t batadv_hash_dat(const void *data, uint32_t size) |
| { |
| const unsigned char *key = data; |
| uint32_t hash = 0; |
| size_t i; |
| |
| for (i = 0; i < 4; i++) { |
| hash += key[i]; |
| hash += (hash << 10); |
| hash ^= (hash >> 6); |
| } |
| |
| hash += (hash << 3); |
| hash ^= (hash >> 11); |
| hash += (hash << 15); |
| |
| 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 |
| * @select: number of already selected candidates |
| * @tmp_max: address of the currently evaluated node |
| * @max: current round max address |
| * @last_max: address of the last selected candidate |
| * @candidate: orig_node under evaluation |
| * @max_orig_node: last selected candidate |
| * |
| * Returns true if the node has been elected as next candidate or false othrwise |
| */ |
| static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res, |
| int select, batadv_dat_addr_t tmp_max, |
| batadv_dat_addr_t max, |
| batadv_dat_addr_t last_max, |
| struct batadv_orig_node *candidate, |
| struct batadv_orig_node *max_orig_node) |
| { |
| bool ret = false; |
| int j; |
| |
| /* Check if this node has already been selected... */ |
| for (j = 0; j < select; j++) |
| if (res[j].orig_node == candidate) |
| break; |
| /* ..and possibly skip it */ |
| if (j < select) |
| goto out; |
| /* sanity check: has it already been selected? This should not happen */ |
| if (tmp_max > last_max) |
| goto out; |
| /* check if during this iteration an originator with a closer dht |
| * address has already been found |
| */ |
| if (tmp_max < max) |
| goto out; |
| /* this is an hash collision with the temporary selected node. Choose |
| * the one with the lowest address |
| */ |
| if ((tmp_max == max) && |
| (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)) |
| goto out; |
| |
| ret = true; |
| out: |
| return ret; |
| } |
| |
| /** |
| * batadv_choose_next_candidate - select the next DHT candidate |
| * @bat_priv: the bat priv with all the soft interface information |
| * @cands: candidates array |
| * @select: number of candidates already present in the array |
| * @ip_key: key to look up in the DHT |
| * @last_max: pointer where the address of the selected candidate will be saved |
| */ |
| static void batadv_choose_next_candidate(struct batadv_priv *bat_priv, |
| struct batadv_dat_candidate *cands, |
| int select, batadv_dat_addr_t ip_key, |
| batadv_dat_addr_t *last_max) |
| { |
| batadv_dat_addr_t max = 0, tmp_max = 0; |
| struct batadv_orig_node *orig_node, *max_orig_node = NULL; |
| struct batadv_hashtable *hash = bat_priv->orig_hash; |
| struct hlist_node *node; |
| struct hlist_head *head; |
| int i; |
| |
| /* if no node is eligible as candidate, leave the candidate type as |
| * NOT_FOUND |
| */ |
| cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND; |
| |
| /* iterate over the originator list and find the node with closest |
| * dat_address which has not been selected yet |
| */ |
| for (i = 0; i < hash->size; i++) { |
| head = &hash->table[i]; |
| |
| rcu_read_lock(); |
| hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) { |
| /* the dht space is a ring and addresses are unsigned */ |
| tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr + |
| ip_key; |
| |
| if (!batadv_is_orig_node_eligible(cands, select, |
| tmp_max, max, |
| *last_max, orig_node, |
| max_orig_node)) |
| continue; |
| |
| if (!atomic_inc_not_zero(&orig_node->refcount)) |
| continue; |
| |
| max = tmp_max; |
| if (max_orig_node) |
| batadv_orig_node_free_ref(max_orig_node); |
| max_orig_node = orig_node; |
| } |
| rcu_read_unlock(); |
| } |
| if (max_orig_node) { |
| cands[select].type = BATADV_DAT_CANDIDATE_ORIG; |
| cands[select].orig_node = max_orig_node; |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n", |
| select, max_orig_node->orig, max_orig_node->dat_addr, |
| max); |
| } |
| *last_max = max; |
| } |
| |
| /** |
| * batadv_dat_select_candidates - selects the nodes which the DHT message has to |
| * be sent to |
| * @bat_priv: the bat priv with all the soft interface information |
| * @ip_dst: ipv4 to look up in the DHT |
| * |
| * An originator O is selected if and only if its DHT_ID value is one of three |
| * closest values (from the LEFT, with wrap around if needed) then the hash |
| * value of the key. ip_dst is the key. |
| * |
| * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM |
| */ |
| static struct batadv_dat_candidate * |
| batadv_dat_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst) |
| { |
| int select; |
| batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key; |
| struct batadv_dat_candidate *res; |
| |
| if (!bat_priv->orig_hash) |
| return NULL; |
| |
| res = kmalloc(BATADV_DAT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); |
| if (!res) |
| return NULL; |
| |
| ip_key = (batadv_dat_addr_t)batadv_hash_dat(&ip_dst, |
| BATADV_DAT_ADDR_MAX); |
| |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, |
| "dat_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst, |
| ip_key); |
| |
| for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++) |
| batadv_choose_next_candidate(bat_priv, res, select, ip_key, |
| &last_max); |
| |
| return res; |
| } |
| |
| /** |
| * batadv_dat_send_data - send a payload to the selected candidates |
| * @bat_priv: the bat priv with all the soft interface information |
| * @skb: payload to send |
| * @ip: the DHT key |
| * @packet_subtype: unicast4addr packet subtype to use |
| * |
| * In this function the skb is copied by means of pskb_copy() and is sent as |
| * unicast packet to each of the selected candidates |
| * |
| * Returns true if the packet is sent to at least one candidate, false otherwise |
| */ |
| static bool batadv_dat_send_data(struct batadv_priv *bat_priv, |
| struct sk_buff *skb, __be32 ip, |
| int packet_subtype) |
| { |
| int i; |
| bool ret = false; |
| int send_status; |
| struct batadv_neigh_node *neigh_node = NULL; |
| struct sk_buff *tmp_skb; |
| struct batadv_dat_candidate *cand; |
| |
| cand = batadv_dat_select_candidates(bat_priv, ip); |
| if (!cand) |
| goto out; |
| |
| batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip); |
| |
| for (i = 0; i < BATADV_DAT_CANDIDATES_NUM; i++) { |
| if (cand[i].type == BATADV_DAT_CANDIDATE_NOT_FOUND) |
| continue; |
| |
| neigh_node = batadv_orig_node_get_router(cand[i].orig_node); |
| if (!neigh_node) |
| goto free_orig; |
| |
| tmp_skb = pskb_copy(skb, GFP_ATOMIC); |
| if (!batadv_unicast_4addr_prepare_skb(bat_priv, tmp_skb, |
| cand[i].orig_node, |
| packet_subtype)) { |
| kfree_skb(tmp_skb); |
| goto free_neigh; |
| } |
| |
| send_status = batadv_send_skb_packet(tmp_skb, |
| neigh_node->if_incoming, |
| neigh_node->addr); |
| if (send_status == NET_XMIT_SUCCESS) |
| /* packet sent to a candidate: return true */ |
| ret = true; |
| free_neigh: |
| batadv_neigh_node_free_ref(neigh_node); |
| free_orig: |
| batadv_orig_node_free_ref(cand[i].orig_node); |
| } |
| |
| out: |
| 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; |
| } |