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batman-adv: substitute tt_poss_change with a per-tt_entry flag 

tt_poss_change is a node-wide flag which tells whether the node is in a roaming
state (a client recently moved to/away from it) in order to let it apply special
re-routing rules. However this flag does not give a clear idea of the current
state because it is not possible to understand *which client* is actually
involved in the roaming. For this reason a better approach has been chosen:
instead of using a node-wide variable, the roaming state is now given by a
per-tt_entry ROAM flag which, in case of packet coming through the node, tells
the node whether the real destination is in roaming state or not.

With this flag change, batadv_check_unicast_ttvn() has also been rearranged in
order to better fit the new re-routing logic and to be much more readable.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
This commit is contained in:
Antonio Quartulli 2012-09-23 22:38:34 +02:00
parent 28709878b6
commit 7c1fd91da5
6 changed files with 158 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
net/batman-adv/originator.c
View File

@ -221,7 +221,6 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
atomic_set(&orig_node->refcount, 2);
orig_node->tt_initialised = false;
orig_node->tt_poss_change = false;
orig_node->bat_priv = bat_priv;
memcpy(orig_node->orig, addr, ETH_ALEN);
batadv_dat_init_orig_node_addr(orig_node);

177
net/batman-adv/routing.c
View File

@ -711,12 +711,6 @@ int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
BATADV_TT_CLIENT_ROAM,
atomic_read(&orig_node->last_ttvn) + 1);
/* Roaming phase starts: I have new information but the ttvn has not
* been incremented yet. This flag will make me check all the incoming
* packets for the correct destination.
*/
bat_priv->tt.poss_change = true;
batadv_orig_node_free_ref(orig_node);
out:
/* returning NET_RX_DROP will make the caller function kfree the skb */
@ -899,14 +893,67 @@ out:
return ret;
}
/**
* batadv_reroute_unicast_packet - update the unicast header for re-routing
* @bat_priv: the bat priv with all the soft interface information
* @unicast_packet: the unicast header to be updated
* @dst_addr: the payload destination
*
* Search the translation table for dst_addr and update the unicast header with
* the new corresponding information (originator address where the destination
* client currently is and its known TTVN)
*
* Returns true if the packet header has been updated, false otherwise
*/
static bool
batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
struct batadv_unicast_packet *unicast_packet,
uint8_t *dst_addr)
{
struct batadv_orig_node *orig_node = NULL;
struct batadv_hard_iface *primary_if = NULL;
bool ret = false;
uint8_t *orig_addr, orig_ttvn;
if (batadv_is_my_client(bat_priv, dst_addr)) {
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
orig_addr = primary_if->net_dev->dev_addr;
orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
} else {
orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
if (!orig_node)
goto out;
if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
goto out;
orig_addr = orig_node->orig;
orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
}
/* update the packet header */
memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
unicast_packet->ttvn = orig_ttvn;
ret = true;
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
struct sk_buff *skb) {
uint8_t curr_ttvn;
uint8_t curr_ttvn, old_ttvn;
struct batadv_orig_node *orig_node;
struct ethhdr *ethhdr;
struct batadv_hard_iface *primary_if;
struct batadv_unicast_packet *unicast_packet;
bool tt_poss_change;
int is_old_ttvn;
/* check if there is enough data before accessing it */
@ -918,65 +965,89 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
return 0;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
if (batadv_is_my_mac(unicast_packet->dest)) {
tt_poss_change = bat_priv->tt.poss_change;
curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
} else {
/* check if the destination client was served by this node and it is now
* roaming. In this case, it means that the node has got a ROAM_ADV
* message and that it knows the new destination in the mesh to re-route
* the packet to
*/
if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
ethhdr->h_dest))
net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
bat_priv,
"Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
unicast_packet->dest,
ethhdr->h_dest);
/* at this point the mesh destination should have been
* substituted with the originator address found in the global
* table. If not, let the packet go untouched anyway because
* there is nothing the node can do
*/
return 1;
}
/* retrieve the TTVN known by this node for the packet destination. This
* value is used later to check if the node which sent (or re-routed
* last time) the packet had an updated information or not
*/
curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
if (!batadv_is_my_mac(unicast_packet->dest)) {
orig_node = batadv_orig_hash_find(bat_priv,
unicast_packet->dest);
/* if it is not possible to find the orig_node representing the
* destination, the packet can immediately be dropped as it will
* not be possible to deliver it
*/
if (!orig_node)
return 0;
curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
tt_poss_change = orig_node->tt_poss_change;
batadv_orig_node_free_ref(orig_node);
}
/* Check whether I have to reroute the packet */
/* check if the TTVN contained in the packet is fresher than what the
* node knows
*/
is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
if (is_old_ttvn || tt_poss_change) {
/* check if there is enough data before accessing it */
if (pskb_may_pull(skb, sizeof(struct batadv_unicast_packet) +
ETH_HLEN) < 0)
return 0;
ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
/* we don't have an updated route for this client, so we should
* not try to reroute the packet!!
*/
if (batadv_tt_global_client_is_roaming(bat_priv,
ethhdr->h_dest))
return 1;
orig_node = batadv_transtable_search(bat_priv, NULL,
ethhdr->h_dest);
if (!orig_node) {
if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
return 0;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
return 0;
memcpy(unicast_packet->dest,
primary_if->net_dev->dev_addr, ETH_ALEN);
batadv_hardif_free_ref(primary_if);
} else {
memcpy(unicast_packet->dest, orig_node->orig,
ETH_ALEN);
curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
batadv_orig_node_free_ref(orig_node);
}
if (!is_old_ttvn)
return 1;
old_ttvn = unicast_packet->ttvn;
/* the packet was forged based on outdated network information. Its
* destination can possibly be updated and forwarded towards the new
* target host
*/
if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
ethhdr->h_dest)) {
net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
"TTVN mismatch (old_ttvn %u new_ttvn %u)! Rerouting unicast packet (for %pM) to %pM\n",
unicast_packet->ttvn, curr_ttvn,
ethhdr->h_dest, unicast_packet->dest);
unicast_packet->ttvn = curr_ttvn;
"Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
unicast_packet->dest, ethhdr->h_dest,
old_ttvn, curr_ttvn);
return 1;
}
/* the packet has not been re-routed: either the destination is
* currently served by this node or there is no destination at all and
* it is possible to drop the packet
*/
if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
return 0;
/* update the header in order to let the packet be delivered to this
* node's soft interface
*/
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
return 0;
memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
batadv_hardif_free_ref(primary_if);
unicast_packet->ttvn = curr_ttvn;
return 1;
}

1
net/batman-adv/soft-interface.c
View File

@ -505,7 +505,6 @@ struct net_device *batadv_softif_create(const char *name)
#endif
bat_priv->tt.last_changeset = NULL;
bat_priv->tt.last_changeset_len = 0;
bat_priv->tt.poss_change = false;
bat_priv->primary_if = NULL;
bat_priv->num_ifaces = 0;

46
net/batman-adv/translation-table.c
View File

@ -306,8 +306,6 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
head = &tt_global_entry->orig_list;
rcu_read_lock();
hlist_for_each_entry_rcu(orig_entry, node, head, list) {
orig_entry->orig_node->tt_poss_change = true;
batadv_send_roam_adv(bat_priv,
tt_global_entry->common.addr,
orig_entry->orig_node);
@ -512,8 +510,11 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv,
curr_flags = tt_local_entry->common.flags;
flags = BATADV_TT_CLIENT_DEL;
if (roaming)
if (roaming) {
flags |= BATADV_TT_CLIENT_ROAM;
/* mark the local client as ROAMed */
tt_local_entry->common.flags |= BATADV_TT_CLIENT_ROAM;
}
batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags, message);
@ -1945,7 +1946,8 @@ bool batadv_is_my_client(struct batadv_priv *bat_priv, const uint8_t *addr)
/* Check if the client has been logically deleted (but is kept for
* consistency purpose)
*/
if (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING)
if ((tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING) ||
(tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM))
goto out;
ret = true;
out:
@ -1996,10 +1998,6 @@ void batadv_handle_tt_response(struct batadv_priv *bat_priv,
/* Recalculate the CRC for this orig_node and store it */
orig_node->tt_crc = batadv_tt_global_crc(bat_priv, orig_node);
/* Roaming phase is over: tables are in sync again. I can
* unset the flag
*/
orig_node->tt_poss_change = false;
out:
if (orig_node)
batadv_orig_node_free_ref(orig_node);
@ -2290,7 +2288,6 @@ static int batadv_tt_commit_changes(struct batadv_priv *bat_priv,
batadv_dbg(BATADV_DBG_TT, bat_priv,
"Local changes committed, updating to ttvn %u\n",
(uint8_t)atomic_read(&bat_priv->tt.vn));
bat_priv->tt.poss_change = false;
/* reset the sending counter */
atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX);
@ -2402,11 +2399,6 @@ void batadv_tt_update_orig(struct batadv_priv *bat_priv,
*/
if (orig_node->tt_crc != tt_crc)
goto request_table;
/* Roaming phase is over: tables are in sync again. I can
* unset the flag
*/
orig_node->tt_poss_change = false;
} else {
/* if we missed more than one change or our tables are not
* in sync anymore -> request fresh tt data
@ -2445,6 +2437,32 @@ out:
return ret;
}
/**
* batadv_tt_local_client_is_roaming - tells whether the client is roaming
* @bat_priv: the bat priv with all the soft interface information
* @addr: the MAC address of the local client to query
*
* Returns true if the local client is known to be roaming (it is not served by
* this node anymore) or not. If yes, the client is still present in the table
* to keep the latter consistent with the node TTVN
*/
bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv,
uint8_t *addr)
{
struct batadv_tt_local_entry *tt_local_entry;
bool ret = false;
tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr);
if (!tt_local_entry)
goto out;
ret = tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM;
batadv_tt_local_entry_free_ref(tt_local_entry);
out:
return ret;
}
bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
const unsigned char *addr)

2
net/batman-adv/translation-table.h
View File

@ -59,6 +59,8 @@ int batadv_tt_append_diff(struct batadv_priv *bat_priv,
int packet_min_len);
bool batadv_tt_global_client_is_roaming(struct batadv_priv *bat_priv,
uint8_t *addr);
bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv,
uint8_t *addr);
bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
const unsigned char *addr);

8
net/batman-adv/types.h
View File

@ -101,13 +101,6 @@ struct batadv_orig_node {
spinlock_t tt_buff_lock; /* protects tt_buff */
atomic_t tt_size;
bool tt_initialised;
/* The tt_poss_change flag is used to detect an ongoing roaming phase.
* If true, then I sent a Roaming_adv to this orig_node and I have to
* inspect every packet directed to it to check whether it is still
* the true destination or not. This flag will be reset to false as
* soon as I receive a new TTVN from this orig_node
*/
bool tt_poss_change;
uint32_t last_real_seqno;
uint8_t last_ttl;
DECLARE_BITMAP(bcast_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
@ -212,7 +205,6 @@ struct batadv_priv_tt {
atomic_t vn;
atomic_t ogm_append_cnt;
atomic_t local_changes;
bool poss_change;
struct list_head changes_list;
struct batadv_hashtable *local_hash;
struct batadv_hashtable *global_hash;