Commit 7c1fd91d authored by Antonio Quartulli's avatar Antonio Quartulli
Browse files

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: default avatarAntonio Quartulli <ordex@autistici.org>
parent 28709878

net/batman-adv/originator.c

+0 −1
Original line number Diff line number Diff line
@@ -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);

net/batman-adv/routing.c

+122 −51
Original line number Diff line number Diff line
@@ -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;

	/* 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);

	} else {

	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));

	if (!is_old_ttvn)

		return 1;



		/* we don't have an updated route for this client, so we should

		 * not try to reroute the packet!!

	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_tt_global_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): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",

					 unicast_packet->dest, ethhdr->h_dest,

					 old_ttvn, curr_ttvn);

		return 1;

	}



		orig_node = batadv_transtable_search(bat_priv, NULL,

						     ethhdr->h_dest);



		if (!orig_node) {

	/* 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);

		} 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);

		}



		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);

	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;

}

net/batman-adv/soft-interface.c

+0 −1
Original line number Diff line number Diff line
@@ -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;

net/batman-adv/translation-table.c

+32 −14
Original line number Diff line number Diff line
@@ -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)

net/batman-adv/translation-table.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

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