/* Copyright (C) 2011-2013 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_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_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(&dat_entry->hash_entry);
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 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, 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) && max_orig_node &&
(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_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, 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_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, 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;
uint8_t *hw_src, *hw_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) ||
ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) ||
ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst))
goto out;
hw_src = batadv_arp_hw_src(skb, hdr_size);
if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src))
goto out;
/* we don't care about the destination MAC address in ARP requests */
if (arphdr->ar_op != htons(ARPOP_REQUEST)) {
hw_dst = batadv_arp_hw_dst(skb, hdr_size);
if (is_zero_ether_addr(hw_dst) ||
is_multicast_ether_addr(hw_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;
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) {
/* If the ARP request is destined for a local client the local
* client will answer itself. DAT would only generate a
* duplicate packet.
*
* Moreover, if the soft-interface is enslaved into a bridge, an
* additional DAT answer may trigger kernel warnings about
* a packet coming from the wrong port.
*/
if (batadv_is_my_client(bat_priv, dat_entry->mac_addr)) {
ret = true;
goto out;
}
skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
bat_priv->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,
bat_priv->soft_iface);
bat_priv->stats.rx_packets++;
bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;
bat_priv->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);
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_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;
skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
bat_priv->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 (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)
kfree_skb(skb);
/* 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;
}