kernel_optimize_test/net/batman-adv/distributed-arp-table.c
Matthias Schiffer 757dd82ea7 batman-adv: check for more types of invalid IP addresses in DAT
There are more types of IP addresses that may appear in ARP packets that we
don't want to process. While some of these should never appear in sane ARP
packets, a 0.0.0.0 source is used for duplicate address detection and thus seen
quite often.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2013-01-27 14:02:39 +01:00

1071 lines
30 KiB
C

/* 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) ||
ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) ||
ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(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)
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;
}