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bridge_loop_avoidance.c
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bridge_loop_avoidance.c
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/* Copyright (C) 2011-2015 B.A.T.M.A.N. contributors:
*
* Simon Wunderlich
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "bridge_loop_avoidance.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
#include <linux/crc16.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/fs.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <net/arp.h>
#include "hard-interface.h"
#include "hash.h"
#include "originator.h"
#include "packet.h"
#include "translation-table.h"
static const u8 batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
static void batadv_bla_periodic_work(struct work_struct *work);
static void
batadv_bla_send_announce(struct batadv_priv *bat_priv,
struct batadv_bla_backbone_gw *backbone_gw);
/* return the index of the claim */
static inline u32 batadv_choose_claim(const void *data, u32 size)
{
struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
u32 hash = 0;
hash = jhash(&claim->addr, sizeof(claim->addr), hash);
hash = jhash(&claim->vid, sizeof(claim->vid), hash);
return hash % size;
}
/* return the index of the backbone gateway */
static inline u32 batadv_choose_backbone_gw(const void *data, u32 size)
{
const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
u32 hash = 0;
hash = jhash(&claim->addr, sizeof(claim->addr), hash);
hash = jhash(&claim->vid, sizeof(claim->vid), hash);
return hash % size;
}
/* compares address and vid of two backbone gws */
static int batadv_compare_backbone_gw(const struct hlist_node *node,
const void *data2)
{
const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
hash_entry);
const struct batadv_bla_backbone_gw *gw1 = data1;
const struct batadv_bla_backbone_gw *gw2 = data2;
if (!batadv_compare_eth(gw1->orig, gw2->orig))
return 0;
if (gw1->vid != gw2->vid)
return 0;
return 1;
}
/* compares address and vid of two claims */
static int batadv_compare_claim(const struct hlist_node *node,
const void *data2)
{
const void *data1 = container_of(node, struct batadv_bla_claim,
hash_entry);
const struct batadv_bla_claim *cl1 = data1;
const struct batadv_bla_claim *cl2 = data2;
if (!batadv_compare_eth(cl1->addr, cl2->addr))
return 0;
if (cl1->vid != cl2->vid)
return 0;
return 1;
}
/* free a backbone gw */
static void
batadv_backbone_gw_free_ref(struct batadv_bla_backbone_gw *backbone_gw)
{
if (atomic_dec_and_test(&backbone_gw->refcount))
kfree_rcu(backbone_gw, rcu);
}
/* finally deinitialize the claim */
static void batadv_claim_release(struct batadv_bla_claim *claim)
{
batadv_backbone_gw_free_ref(claim->backbone_gw);
kfree_rcu(claim, rcu);
}
/* free a claim, call claim_free_rcu if its the last reference */
static void batadv_claim_free_ref(struct batadv_bla_claim *claim)
{
if (atomic_dec_and_test(&claim->refcount))
batadv_claim_release(claim);
}
/**
* batadv_claim_hash_find
* @bat_priv: the bat priv with all the soft interface information
* @data: search data (may be local/static data)
*
* looks for a claim in the hash, and returns it if found
* or NULL otherwise.
*/
static struct batadv_bla_claim
*batadv_claim_hash_find(struct batadv_priv *bat_priv,
struct batadv_bla_claim *data)
{
struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
struct hlist_head *head;
struct batadv_bla_claim *claim;
struct batadv_bla_claim *claim_tmp = NULL;
int index;
if (!hash)
return NULL;
index = batadv_choose_claim(data, hash->size);
head = &hash->table[index];
rcu_read_lock();
hlist_for_each_entry_rcu(claim, head, hash_entry) {
if (!batadv_compare_claim(&claim->hash_entry, data))
continue;
if (!atomic_inc_not_zero(&claim->refcount))
continue;
claim_tmp = claim;
break;
}
rcu_read_unlock();
return claim_tmp;
}
/**
* batadv_backbone_hash_find - looks for a claim in the hash
* @bat_priv: the bat priv with all the soft interface information
* @addr: the address of the originator
* @vid: the VLAN ID
*
* Returns claim if found or NULL otherwise.
*/
static struct batadv_bla_backbone_gw *
batadv_backbone_hash_find(struct batadv_priv *bat_priv, u8 *addr,
unsigned short vid)
{
struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
struct hlist_head *head;
struct batadv_bla_backbone_gw search_entry, *backbone_gw;
struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
int index;
if (!hash)
return NULL;
ether_addr_copy(search_entry.orig, addr);
search_entry.vid = vid;
index = batadv_choose_backbone_gw(&search_entry, hash->size);
head = &hash->table[index];
rcu_read_lock();
hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
&search_entry))
continue;
if (!atomic_inc_not_zero(&backbone_gw->refcount))
continue;
backbone_gw_tmp = backbone_gw;
break;
}
rcu_read_unlock();
return backbone_gw_tmp;
}
/* delete all claims for a backbone */
static void
batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
{
struct batadv_hashtable *hash;
struct hlist_node *node_tmp;
struct hlist_head *head;
struct batadv_bla_claim *claim;
int i;
spinlock_t *list_lock; /* protects write access to the hash lists */
hash = backbone_gw->bat_priv->bla.claim_hash;
if (!hash)
return;
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
list_lock = &hash->list_locks[i];
spin_lock_bh(list_lock);
hlist_for_each_entry_safe(claim, node_tmp,
head, hash_entry) {
if (claim->backbone_gw != backbone_gw)
continue;
batadv_claim_free_ref(claim);
hlist_del_rcu(&claim->hash_entry);
}
spin_unlock_bh(list_lock);
}
/* all claims gone, initialize CRC */
backbone_gw->crc = BATADV_BLA_CRC_INIT;
}
/**
* batadv_bla_send_claim - sends a claim frame according to the provided info
* @bat_priv: the bat priv with all the soft interface information
* @mac: the mac address to be announced within the claim
* @vid: the VLAN ID
* @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
*/
static void batadv_bla_send_claim(struct batadv_priv *bat_priv, u8 *mac,
unsigned short vid, int claimtype)
{
struct sk_buff *skb;
struct ethhdr *ethhdr;
struct batadv_hard_iface *primary_if;
struct net_device *soft_iface;
u8 *hw_src;
struct batadv_bla_claim_dst local_claim_dest;
__be32 zeroip = 0;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
return;
memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
sizeof(local_claim_dest));
local_claim_dest.type = claimtype;
soft_iface = primary_if->soft_iface;
skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
/* IP DST: 0.0.0.0 */
zeroip,
primary_if->soft_iface,
/* IP SRC: 0.0.0.0 */
zeroip,
/* Ethernet DST: Broadcast */
NULL,
/* Ethernet SRC/HW SRC: originator mac */
primary_if->net_dev->dev_addr,
/* HW DST: FF:43:05:XX:YY:YY
* with XX = claim type
* and YY:YY = group id
*/
(u8 *)&local_claim_dest);
if (!skb)
goto out;
ethhdr = (struct ethhdr *)skb->data;
hw_src = (u8 *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
/* now we pretend that the client would have sent this ... */
switch (claimtype) {
case BATADV_CLAIM_TYPE_CLAIM:
/* normal claim frame
* set Ethernet SRC to the clients mac
*/
ether_addr_copy(ethhdr->h_source, mac);
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_send_claim(): CLAIM %pM on vid %d\n", mac,
BATADV_PRINT_VID(vid));
break;
case BATADV_CLAIM_TYPE_UNCLAIM:
/* unclaim frame
* set HW SRC to the clients mac
*/
ether_addr_copy(hw_src, mac);
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
BATADV_PRINT_VID(vid));
break;
case BATADV_CLAIM_TYPE_ANNOUNCE:
/* announcement frame
* set HW SRC to the special mac containg the crc
*/
ether_addr_copy(hw_src, mac);
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
ethhdr->h_source, BATADV_PRINT_VID(vid));
break;
case BATADV_CLAIM_TYPE_REQUEST:
/* request frame
* set HW SRC and header destination to the receiving backbone
* gws mac
*/
ether_addr_copy(hw_src, mac);
ether_addr_copy(ethhdr->h_dest, mac);
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_send_claim(): REQUEST of %pM to %pM on vid %d\n",
ethhdr->h_source, ethhdr->h_dest,
BATADV_PRINT_VID(vid));
break;
}
if (vid & BATADV_VLAN_HAS_TAG)
skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
vid & VLAN_VID_MASK);
skb_reset_mac_header(skb);
skb->protocol = eth_type_trans(skb, soft_iface);
batadv_inc_counter(bat_priv, BATADV_CNT_RX);
batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
skb->len + ETH_HLEN);
soft_iface->last_rx = jiffies;
netif_rx(skb);
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
}
/**
* batadv_bla_get_backbone_gw
* @bat_priv: the bat priv with all the soft interface information
* @orig: the mac address of the originator
* @vid: the VLAN ID
* @own_backbone: set if the requested backbone is local
*
* searches for the backbone gw or creates a new one if it could not
* be found.
*/
static struct batadv_bla_backbone_gw *
batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig,
unsigned short vid, bool own_backbone)
{
struct batadv_bla_backbone_gw *entry;
struct batadv_orig_node *orig_node;
int hash_added;
entry = batadv_backbone_hash_find(bat_priv, orig, vid);
if (entry)
return entry;
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
orig, BATADV_PRINT_VID(vid));
entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
if (!entry)
return NULL;
entry->vid = vid;
entry->lasttime = jiffies;
entry->crc = BATADV_BLA_CRC_INIT;
entry->bat_priv = bat_priv;
atomic_set(&entry->request_sent, 0);
atomic_set(&entry->wait_periods, 0);
ether_addr_copy(entry->orig, orig);
/* one for the hash, one for returning */
atomic_set(&entry->refcount, 2);
hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
batadv_compare_backbone_gw,
batadv_choose_backbone_gw, entry,
&entry->hash_entry);
if (unlikely(hash_added != 0)) {
/* hash failed, free the structure */
kfree(entry);
return NULL;
}
/* this is a gateway now, remove any TT entry on this VLAN */
orig_node = batadv_orig_hash_find(bat_priv, orig);
if (orig_node) {
batadv_tt_global_del_orig(bat_priv, orig_node, vid,
"became a backbone gateway");
batadv_orig_node_free_ref(orig_node);
}
if (own_backbone) {
batadv_bla_send_announce(bat_priv, entry);
/* this will be decreased in the worker thread */
atomic_inc(&entry->request_sent);
atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
atomic_inc(&bat_priv->bla.num_requests);
}
return entry;
}
/* update or add the own backbone gw to make sure we announce
* where we receive other backbone gws
*/
static void
batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
unsigned short vid)
{
struct batadv_bla_backbone_gw *backbone_gw;
backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
primary_if->net_dev->dev_addr,
vid, true);
if (unlikely(!backbone_gw))
return;
backbone_gw->lasttime = jiffies;
batadv_backbone_gw_free_ref(backbone_gw);
}
/**
* batadv_bla_answer_request - answer a bla request by sending own claims
* @bat_priv: the bat priv with all the soft interface information
* @primary_if: interface where the request came on
* @vid: the vid where the request came on
*
* Repeat all of our own claims, and finally send an ANNOUNCE frame
* to allow the requester another check if the CRC is correct now.
*/
static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
unsigned short vid)
{
struct hlist_head *head;
struct batadv_hashtable *hash;
struct batadv_bla_claim *claim;
struct batadv_bla_backbone_gw *backbone_gw;
int i;
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_answer_request(): received a claim request, send all of our own claims again\n");
backbone_gw = batadv_backbone_hash_find(bat_priv,
primary_if->net_dev->dev_addr,
vid);
if (!backbone_gw)
return;
hash = bat_priv->bla.claim_hash;
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
rcu_read_lock();
hlist_for_each_entry_rcu(claim, head, hash_entry) {
/* only own claims are interesting */
if (claim->backbone_gw != backbone_gw)
continue;
batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
BATADV_CLAIM_TYPE_CLAIM);
}
rcu_read_unlock();
}
/* finally, send an announcement frame */
batadv_bla_send_announce(bat_priv, backbone_gw);
batadv_backbone_gw_free_ref(backbone_gw);
}
/**
* batadv_bla_send_request - send a request to repeat claims
* @backbone_gw: the backbone gateway from whom we are out of sync
*
* When the crc is wrong, ask the backbone gateway for a full table update.
* After the request, it will repeat all of his own claims and finally
* send an announcement claim with which we can check again.
*/
static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw)
{
/* first, remove all old entries */
batadv_bla_del_backbone_claims(backbone_gw);
batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
"Sending REQUEST to %pM\n", backbone_gw->orig);
/* send request */
batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
/* no local broadcasts should be sent or received, for now. */
if (!atomic_read(&backbone_gw->request_sent)) {
atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
atomic_set(&backbone_gw->request_sent, 1);
}
}
/**
* batadv_bla_send_announce
* @bat_priv: the bat priv with all the soft interface information
* @backbone_gw: our backbone gateway which should be announced
*
* This function sends an announcement. It is called from multiple
* places.
*/
static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
struct batadv_bla_backbone_gw *backbone_gw)
{
u8 mac[ETH_ALEN];
__be16 crc;
memcpy(mac, batadv_announce_mac, 4);
crc = htons(backbone_gw->crc);
memcpy(&mac[4], &crc, 2);
batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
BATADV_CLAIM_TYPE_ANNOUNCE);
}
/**
* batadv_bla_add_claim - Adds a claim in the claim hash
* @bat_priv: the bat priv with all the soft interface information
* @mac: the mac address of the claim
* @vid: the VLAN ID of the frame
* @backbone_gw: the backbone gateway which claims it
*/
static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
const u8 *mac, const unsigned short vid,
struct batadv_bla_backbone_gw *backbone_gw)
{
struct batadv_bla_claim *claim;
struct batadv_bla_claim search_claim;
int hash_added;
ether_addr_copy(search_claim.addr, mac);
search_claim.vid = vid;
claim = batadv_claim_hash_find(bat_priv, &search_claim);
/* create a new claim entry if it does not exist yet. */
if (!claim) {
claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
if (!claim)
return;
ether_addr_copy(claim->addr, mac);
claim->vid = vid;
claim->lasttime = jiffies;
claim->backbone_gw = backbone_gw;
atomic_set(&claim->refcount, 2);
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
mac, BATADV_PRINT_VID(vid));
hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
batadv_compare_claim,
batadv_choose_claim, claim,
&claim->hash_entry);
if (unlikely(hash_added != 0)) {
/* only local changes happened. */
kfree(claim);
return;
}
} else {
claim->lasttime = jiffies;
if (claim->backbone_gw == backbone_gw)
/* no need to register a new backbone */
goto claim_free_ref;
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_add_claim(): changing ownership for %pM, vid %d\n",
mac, BATADV_PRINT_VID(vid));
claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
batadv_backbone_gw_free_ref(claim->backbone_gw);
}
/* set (new) backbone gw */
atomic_inc(&backbone_gw->refcount);
claim->backbone_gw = backbone_gw;
backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
backbone_gw->lasttime = jiffies;
claim_free_ref:
batadv_claim_free_ref(claim);
}
/* Delete a claim from the claim hash which has the
* given mac address and vid.
*/
static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
const u8 *mac, const unsigned short vid)
{
struct batadv_bla_claim search_claim, *claim;
ether_addr_copy(search_claim.addr, mac);
search_claim.vid = vid;
claim = batadv_claim_hash_find(bat_priv, &search_claim);
if (!claim)
return;
batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
mac, BATADV_PRINT_VID(vid));
batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
batadv_choose_claim, claim);
batadv_claim_free_ref(claim); /* reference from the hash is gone */
claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
/* don't need the reference from hash_find() anymore */
batadv_claim_free_ref(claim);
}
/* check for ANNOUNCE frame, return 1 if handled */
static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
u8 *backbone_addr, unsigned short vid)
{
struct batadv_bla_backbone_gw *backbone_gw;
u16 crc;
if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
return 0;
backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
false);
if (unlikely(!backbone_gw))
return 1;
/* handle as ANNOUNCE frame */
backbone_gw->lasttime = jiffies;
crc = ntohs(*((__be16 *)(&an_addr[4])));
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
BATADV_PRINT_VID(vid), backbone_gw->orig, crc);
if (backbone_gw->crc != crc) {
batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
"handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
backbone_gw->orig,
BATADV_PRINT_VID(backbone_gw->vid),
backbone_gw->crc, crc);
batadv_bla_send_request(backbone_gw);
} else {
/* if we have sent a request and the crc was OK,
* we can allow traffic again.
*/
if (atomic_read(&backbone_gw->request_sent)) {
atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
atomic_set(&backbone_gw->request_sent, 0);
}
}
batadv_backbone_gw_free_ref(backbone_gw);
return 1;
}
/* check for REQUEST frame, return 1 if handled */
static int batadv_handle_request(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
u8 *backbone_addr, struct ethhdr *ethhdr,
unsigned short vid)
{
/* check for REQUEST frame */
if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
return 0;
/* sanity check, this should not happen on a normal switch,
* we ignore it in this case.
*/
if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
return 1;
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"handle_request(): REQUEST vid %d (sent by %pM)...\n",
BATADV_PRINT_VID(vid), ethhdr->h_source);
batadv_bla_answer_request(bat_priv, primary_if, vid);
return 1;
}
/* check for UNCLAIM frame, return 1 if handled */
static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
u8 *backbone_addr, u8 *claim_addr,
unsigned short vid)
{
struct batadv_bla_backbone_gw *backbone_gw;
/* unclaim in any case if it is our own */
if (primary_if && batadv_compare_eth(backbone_addr,
primary_if->net_dev->dev_addr))
batadv_bla_send_claim(bat_priv, claim_addr, vid,
BATADV_CLAIM_TYPE_UNCLAIM);
backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
if (!backbone_gw)
return 1;
/* this must be an UNCLAIM frame */
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
claim_addr, BATADV_PRINT_VID(vid), backbone_gw->orig);
batadv_bla_del_claim(bat_priv, claim_addr, vid);
batadv_backbone_gw_free_ref(backbone_gw);
return 1;
}
/* check for CLAIM frame, return 1 if handled */
static int batadv_handle_claim(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
u8 *backbone_addr, u8 *claim_addr,
unsigned short vid)
{
struct batadv_bla_backbone_gw *backbone_gw;
/* register the gateway if not yet available, and add the claim. */
backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
false);
if (unlikely(!backbone_gw))
return 1;
/* this must be a CLAIM frame */
batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
batadv_bla_send_claim(bat_priv, claim_addr, vid,
BATADV_CLAIM_TYPE_CLAIM);
/* TODO: we could call something like tt_local_del() here. */
batadv_backbone_gw_free_ref(backbone_gw);
return 1;
}
/**
* batadv_check_claim_group
* @bat_priv: the bat priv with all the soft interface information
* @primary_if: the primary interface of this batman interface
* @hw_src: the Hardware source in the ARP Header
* @hw_dst: the Hardware destination in the ARP Header
* @ethhdr: pointer to the Ethernet header of the claim frame
*
* checks if it is a claim packet and if its on the same group.
* This function also applies the group ID of the sender
* if it is in the same mesh.
*
* returns:
* 2 - if it is a claim packet and on the same group
* 1 - if is a claim packet from another group
* 0 - if it is not a claim packet
*/
static int batadv_check_claim_group(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
u8 *hw_src, u8 *hw_dst,
struct ethhdr *ethhdr)
{
u8 *backbone_addr;
struct batadv_orig_node *orig_node;
struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
bla_dst_own = &bat_priv->bla.claim_dest;
/* if announcement packet, use the source,
* otherwise assume it is in the hw_src
*/
switch (bla_dst->type) {
case BATADV_CLAIM_TYPE_CLAIM:
backbone_addr = hw_src;
break;
case BATADV_CLAIM_TYPE_REQUEST:
case BATADV_CLAIM_TYPE_ANNOUNCE:
case BATADV_CLAIM_TYPE_UNCLAIM:
backbone_addr = ethhdr->h_source;
break;
default:
return 0;
}
/* don't accept claim frames from ourselves */
if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
return 0;
/* if its already the same group, it is fine. */
if (bla_dst->group == bla_dst_own->group)
return 2;
/* lets see if this originator is in our mesh */
orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
/* dont accept claims from gateways which are not in
* the same mesh or group.
*/
if (!orig_node)
return 1;
/* if our mesh friends mac is bigger, use it for ourselves. */
if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"taking other backbones claim group: %#.4x\n",
ntohs(bla_dst->group));
bla_dst_own->group = bla_dst->group;
}
batadv_orig_node_free_ref(orig_node);
return 2;
}
/**
* batadv_bla_process_claim
* @bat_priv: the bat priv with all the soft interface information
* @primary_if: the primary hard interface of this batman soft interface
* @skb: the frame to be checked
*
* Check if this is a claim frame, and process it accordingly.
*
* returns 1 if it was a claim frame, otherwise return 0 to
* tell the callee that it can use the frame on its own.
*/
static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
struct batadv_hard_iface *primary_if,
struct sk_buff *skb)
{
struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
u8 *hw_src, *hw_dst;
struct vlan_hdr *vhdr, vhdr_buf;
struct ethhdr *ethhdr;
struct arphdr *arphdr;
unsigned short vid;
int vlan_depth = 0;
__be16 proto;
int headlen;
int ret;
vid = batadv_get_vid(skb, 0);
ethhdr = eth_hdr(skb);
proto = ethhdr->h_proto;
headlen = ETH_HLEN;
if (vid & BATADV_VLAN_HAS_TAG) {
/* Traverse the VLAN/Ethertypes.
*
* At this point it is known that the first protocol is a VLAN
* header, so start checking at the encapsulated protocol.
*
* The depth of the VLAN headers is recorded to drop BLA claim
* frames encapsulated into multiple VLAN headers (QinQ).
*/
do {
vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
&vhdr_buf);
if (!vhdr)
return 0;
proto = vhdr->h_vlan_encapsulated_proto;
headlen += VLAN_HLEN;
vlan_depth++;
} while (proto == htons(ETH_P_8021Q));
}
if (proto != htons(ETH_P_ARP))
return 0; /* not a claim frame */
/* this must be a ARP frame. check if it is a claim. */
if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
return 0;
/* pskb_may_pull() may have modified the pointers, get ethhdr again */
ethhdr = eth_hdr(skb);
arphdr = (struct arphdr *)((u8 *)ethhdr + headlen);
/* Check whether the ARP frame carries a valid
* IP information
*/
if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
return 0;
if (arphdr->ar_pro != htons(ETH_P_IP))
return 0;
if (arphdr->ar_hln != ETH_ALEN)
return 0;
if (arphdr->ar_pln != 4)
return 0;
hw_src = (u8 *)arphdr + sizeof(struct arphdr);
hw_dst = hw_src + ETH_ALEN + 4;
bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
bla_dst_own = &bat_priv->bla.claim_dest;
/* check if it is a claim frame in general */
if (memcmp(bla_dst->magic, bla_dst_own->magic,
sizeof(bla_dst->magic)) != 0)
return 0;
/* check if there is a claim frame encapsulated deeper in (QinQ) and
* drop that, as this is not supported by BLA but should also not be
* sent via the mesh.
*/
if (vlan_depth > 1)
return 1;
/* check if it is a claim frame. */
ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
ethhdr);
if (ret == 1)
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src,
hw_dst);
if (ret < 2)
return ret;
/* become a backbone gw ourselves on this vlan if not happened yet */
batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
/* check for the different types of claim frames ... */
switch (bla_dst->type) {
case BATADV_CLAIM_TYPE_CLAIM:
if (batadv_handle_claim(bat_priv, primary_if, hw_src,
ethhdr->h_source, vid))
return 1;
break;
case BATADV_CLAIM_TYPE_UNCLAIM:
if (batadv_handle_unclaim(bat_priv, primary_if,
ethhdr->h_source, hw_src, vid))
return 1;
break;
case BATADV_CLAIM_TYPE_ANNOUNCE:
if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
vid))
return 1;
break;
case BATADV_CLAIM_TYPE_REQUEST:
if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
vid))
return 1;
break;
}
batadv_dbg(BATADV_DBG_BLA, bat_priv,
"bla_process_claim(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
ethhdr->h_source, BATADV_PRINT_VID(vid), hw_src, hw_dst);
return 1;
}
/* Check when we last heard from other nodes, and remove them in case of
* a time out, or clean all backbone gws if now is set.