diff options
Diffstat (limited to 'net/batman-adv/distributed-arp-table.c')
| -rw-r--r-- | net/batman-adv/distributed-arp-table.c | 1066 |
1 files changed, 1066 insertions, 0 deletions
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c new file mode 100644 index 0000000..8e1d89d --- /dev/null +++ b/net/batman-adv/distributed-arp-table.c @@ -0,0 +1,1066 @@ +/* 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 <net/arp.h> + +#include "main.h" +#include "hash.h" +#include "distributed-arp-table.h" +#include "hard-interface.h" +#include "originator.h" +#include "send.h" +#include "types.h" +#include "translation-table.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_arp_hw_src - extract the hw_src field from an ARP packet + * @skb: ARP packet + * @hdr_size: size of the possible header before the ARP packet + * + * Returns the value of the hw_src field in the ARP packet + */ +static uint8_t *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size) +{ + uint8_t *addr; + + addr = (uint8_t *)(skb->data + hdr_size); + addr += ETH_HLEN + sizeof(struct arphdr); + + return addr; +} + +/** + * batadv_arp_ip_src - extract the ip_src field from an ARP packet + * @skb: ARP packet + * @hdr_size: size of the possible header before the ARP packet + * + * Returns the value of the ip_src field in the ARP packet + */ +static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size) +{ + return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN); +} + +/** + * batadv_arp_hw_dst - extract the hw_dst field from an ARP packet + * @skb: ARP packet + * @hdr_size: size of the possible header before the ARP packet + * + * Returns the value of the hw_dst field in the ARP packet + */ +static uint8_t *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size) +{ + return batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN + 4; +} + +/** + * batadv_arp_ip_dst - extract the ip_dst field from an ARP packet + * @skb: ARP packet + * @hdr_size: size of the possible header before the ARP packet + * + * Returns the value of the ip_dst field in the ARP packet + */ +static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size) +{ + return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4); +} + +/** + * 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); +} + +#ifdef CONFIG_BATMAN_ADV_DEBUG + +/** + * batadv_dbg_arp - print a debug message containing all the ARP packet details + * @bat_priv: the bat priv with all the soft interface information + * @skb: ARP packet + * @type: ARP type + * @hdr_size: size of the possible header before the ARP packet + * @msg: message to print together with the debugging information + */ +static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb, + uint16_t type, int hdr_size, char *msg) +{ + struct batadv_unicast_4addr_packet *unicast_4addr_packet; + struct batadv_bcast_packet *bcast_pkt; + uint8_t *orig_addr; + __be32 ip_src, ip_dst; + + if (msg) + batadv_dbg(BATADV_DBG_DAT, bat_priv, "%s\n", msg); + + ip_src = batadv_arp_ip_src(skb, hdr_size); + ip_dst = batadv_arp_ip_dst(skb, hdr_size); + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n", + batadv_arp_hw_src(skb, hdr_size), &ip_src, + batadv_arp_hw_dst(skb, hdr_size), &ip_dst); + + if (hdr_size == 0) + return; + + /* if the ARP packet is encapsulated in a batman packet, let's print + * some debug messages + */ + unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data; + + switch (unicast_4addr_packet->u.header.packet_type) { + case BATADV_UNICAST: + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "* encapsulated within a UNICAST packet\n"); + break; + case BATADV_UNICAST_4ADDR: + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n", + unicast_4addr_packet->src); + switch (unicast_4addr_packet->subtype) { + case BATADV_P_DAT_DHT_PUT: + batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n"); + break; + case BATADV_P_DAT_DHT_GET: + batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n"); + break; + case BATADV_P_DAT_CACHE_REPLY: + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "* type: DAT_CACHE_REPLY\n"); + break; + case BATADV_P_DATA: + batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n"); + break; + default: + batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n", + unicast_4addr_packet->u.header.packet_type); + } + break; + case BATADV_BCAST: + bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet; + orig_addr = bcast_pkt->orig; + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "* encapsulated within a BCAST packet (src: %pM)\n", + orig_addr); + break; + default: + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "* encapsulated within an unknown packet type (0x%x)\n", + unicast_4addr_packet->u.header.packet_type); + } +} + +#else + +static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb, + uint16_t type, int hdr_size, char *msg) +{ +} + +#endif /* CONFIG_BATMAN_ADV_DEBUG */ + +/** + * 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) { + /* count the sent packet */ + switch (packet_subtype) { + case BATADV_P_DAT_DHT_GET: + batadv_inc_counter(bat_priv, + BATADV_CNT_DAT_GET_TX); + break; + case BATADV_P_DAT_DHT_PUT: + batadv_inc_counter(bat_priv, + BATADV_CNT_DAT_PUT_TX); + break; + } + + /* 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) +{ + if (!bat_priv->dat.hash) + return; + + __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; +} + +/** + * batadv_arp_get_type - parse an ARP packet and gets the type + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to analyse + * @hdr_size: size of the possible header before the ARP packet in the skb + * + * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise + */ +static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + struct arphdr *arphdr; + struct ethhdr *ethhdr; + __be32 ip_src, ip_dst; + uint16_t type = 0; + + /* pull the ethernet header */ + if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN))) + goto out; + + ethhdr = (struct ethhdr *)(skb->data + hdr_size); + + if (ethhdr->h_proto != htons(ETH_P_ARP)) + goto out; + + /* pull the ARP payload */ + if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN + + arp_hdr_len(skb->dev)))) + goto out; + + arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN); + + /* Check whether the ARP packet carries a valid + * IP information + */ + if (arphdr->ar_hrd != htons(ARPHRD_ETHER)) + goto out; + + if (arphdr->ar_pro != htons(ETH_P_IP)) + goto out; + + if (arphdr->ar_hln != ETH_ALEN) + goto out; + + if (arphdr->ar_pln != 4) + goto out; + + /* Check for bad reply/request. If the ARP message is not sane, DAT + * will simply ignore it + */ + ip_src = batadv_arp_ip_src(skb, hdr_size); + ip_dst = batadv_arp_ip_dst(skb, hdr_size); + if (ipv4_is_loopback(ip_src) || ipv4_is_multicast(ip_src) || + ipv4_is_loopback(ip_dst) || ipv4_is_multicast(ip_dst)) + goto out; + + type = ntohs(arphdr->ar_op); +out: + return type; +} + +/** + * batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to + * answer using DAT + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to check + * + * Returns true if the message has been sent to the dht candidates, false + * otherwise. In case of true the message has to be enqueued to permit the + * fallback + */ +bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + uint16_t type = 0; + __be32 ip_dst, ip_src; + uint8_t *hw_src; + bool ret = false; + struct batadv_dat_entry *dat_entry = NULL; + struct sk_buff *skb_new; + struct batadv_hard_iface *primary_if = NULL; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + goto out; + + type = batadv_arp_get_type(bat_priv, skb, 0); + /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast + * message to the selected DHT candidates + */ + if (type != ARPOP_REQUEST) + goto out; + + batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REQUEST"); + + ip_src = batadv_arp_ip_src(skb, 0); + hw_src = batadv_arp_hw_src(skb, 0); + ip_dst = batadv_arp_ip_dst(skb, 0); + + batadv_dat_entry_add(bat_priv, ip_src, hw_src); + + dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); + if (dat_entry) { + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, + primary_if->soft_iface, ip_dst, hw_src, + dat_entry->mac_addr, hw_src); + if (!skb_new) + goto out; + + skb_reset_mac_header(skb_new); + skb_new->protocol = eth_type_trans(skb_new, + primary_if->soft_iface); + bat_priv->stats.rx_packets++; + bat_priv->stats.rx_bytes += skb->len + ETH_HLEN; + primary_if->soft_iface->last_rx = jiffies; + + netif_rx(skb_new); + batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n"); + ret = true; + } else { + /* Send the request on the DHT */ + ret = batadv_dat_send_data(bat_priv, skb, ip_dst, + BATADV_P_DAT_DHT_GET); + } +out: + if (dat_entry) + batadv_dat_entry_free_ref(dat_entry); + if (primary_if) + batadv_hardif_free_ref(primary_if); + return ret; +} + +/** + * batadv_dat_snoop_incoming_arp_request - snoop the ARP request and try to + * answer using the local DAT storage + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to check + * @hdr_size: size of the encapsulation header + * + * Returns true if the request has been answered, false otherwise + */ +bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + uint16_t type; + __be32 ip_src, ip_dst; + uint8_t *hw_src; + struct sk_buff *skb_new; + struct batadv_hard_iface *primary_if = NULL; + struct batadv_dat_entry *dat_entry = NULL; + bool ret = false; + int err; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + goto out; + + type = batadv_arp_get_type(bat_priv, skb, hdr_size); + if (type != ARPOP_REQUEST) + goto out; + + hw_src = batadv_arp_hw_src(skb, hdr_size); + ip_src = batadv_arp_ip_src(skb, hdr_size); + ip_dst = batadv_arp_ip_dst(skb, hdr_size); + + batadv_dbg_arp(bat_priv, skb, type, hdr_size, + "Parsing incoming ARP REQUEST"); + + batadv_dat_entry_add(bat_priv, ip_src, hw_src); + + dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); + if (!dat_entry) + goto out; + + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + + skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, + primary_if->soft_iface, ip_dst, hw_src, + dat_entry->mac_addr, hw_src); + + if (!skb_new) + goto out; + + /* to preserve backwards compatibility, here the node has to answer + * using the same packet type it received for the request. This is due + * to that if a node is not using the 4addr packet format it may not + * support it. + */ + if (hdr_size == sizeof(struct batadv_unicast_4addr_packet)) + err = batadv_unicast_4addr_send_skb(bat_priv, skb_new, + BATADV_P_DAT_CACHE_REPLY); + else + err = batadv_unicast_send_skb(bat_priv, skb_new); + + if (!err) { + batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX); + ret = true; + } +out: + if (dat_entry) + batadv_dat_entry_free_ref(dat_entry); + if (primary_if) + batadv_hardif_free_ref(primary_if); + if (ret) + kfree_skb(skb); + return ret; +} + +/** + * batadv_dat_snoop_outgoing_arp_reply - snoop the ARP reply and fill the DHT + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to check + */ +void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + uint16_t type; + __be32 ip_src, ip_dst; + uint8_t *hw_src, *hw_dst; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + return; + + type = batadv_arp_get_type(bat_priv, skb, 0); + if (type != ARPOP_REPLY) + return; + + batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REPLY"); + + hw_src = batadv_arp_hw_src(skb, 0); + ip_src = batadv_arp_ip_src(skb, 0); + hw_dst = batadv_arp_hw_dst(skb, 0); + ip_dst = batadv_arp_ip_dst(skb, 0); + + batadv_dat_entry_add(bat_priv, ip_src, hw_src); + batadv_dat_entry_add(bat_priv, ip_dst, hw_dst); + + /* Send the ARP reply to the candidates for both the IP addresses that + * the node got within the ARP reply + */ + batadv_dat_send_data(bat_priv, skb, ip_src, BATADV_P_DAT_DHT_PUT); + batadv_dat_send_data(bat_priv, skb, ip_dst, BATADV_P_DAT_DHT_PUT); +} +/** + * batadv_dat_snoop_incoming_arp_reply - snoop the ARP reply and fill the local + * DAT storage only + * @bat_priv: the bat priv with all the soft interface information + * @skb: packet to check + * @hdr_size: siaze of the encapsulation header + */ +bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, + struct sk_buff *skb, int hdr_size) +{ + uint16_t type; + __be32 ip_src, ip_dst; + uint8_t *hw_src, *hw_dst; + bool ret = false; + + if (!atomic_read(&bat_priv->distributed_arp_table)) + goto out; + + type = batadv_arp_get_type(bat_priv, skb, hdr_size); + if (type != ARPOP_REPLY) + goto out; + + batadv_dbg_arp(bat_priv, skb, type, hdr_size, + "Parsing incoming ARP REPLY"); + + hw_src = batadv_arp_hw_src(skb, hdr_size); + ip_src = batadv_arp_ip_src(skb, hdr_size); + hw_dst = batadv_arp_hw_dst(skb, hdr_size); + ip_dst = batadv_arp_ip_dst(skb, hdr_size); + + /* Update our internal cache with both the IP addresses the node got + * within the ARP reply + */ + batadv_dat_entry_add(bat_priv, ip_src, hw_src); + batadv_dat_entry_add(bat_priv, ip_dst, hw_dst); + + /* if this REPLY is directed to a client of mine, let's deliver the + * packet to the interface + */ + ret = !batadv_is_my_client(bat_priv, hw_dst); +out: + /* if ret == false -> packet has to be delivered to the interface */ + return ret; +} + +/** + * batadv_dat_drop_broadcast_packet - check if an ARP request has to be dropped + * (because the node has already got the reply via DAT) or not + * @bat_priv: the bat priv with all the soft interface information + * @forw_packet: the broadcast packet + * + * Returns true if the node can drop the packet, false otherwise + */ +bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv, + struct batadv_forw_packet *forw_packet) +{ + uint16_t type; + __be32 ip_dst; + struct batadv_dat_entry *dat_entry = NULL; + bool ret = false; + const size_t bcast_len = sizeof(struct batadv_bcast_packet); + + if (!atomic_read(&bat_priv->distributed_arp_table)) + goto out; + + /* If this packet is an ARP_REQUEST and the node already has the + * information that it is going to ask, then the packet can be dropped + */ + if (forw_packet->num_packets) + goto out; + + type = batadv_arp_get_type(bat_priv, forw_packet->skb, bcast_len); + if (type != ARPOP_REQUEST) + goto out; + + ip_dst = batadv_arp_ip_dst(forw_packet->skb, bcast_len); + dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); + /* check if the node already got this entry */ + if (!dat_entry) { + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "ARP Request for %pI4: fallback\n", &ip_dst); + goto out; + } + + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "ARP Request for %pI4: fallback prevented\n", &ip_dst); + ret = true; + +out: + if (dat_entry) + batadv_dat_entry_free_ref(dat_entry); + return ret; +} |
