a73105b8d4
The client announcement mechanism informs every mesh node in the network of any connected non-mesh client, in order to find the path towards that client from any given point in the mesh. The old implementation was based on the simple idea of appending a data buffer to each OGM containing all the client MAC addresses the node is serving. All other nodes can populate their global translation tables (table which links client MAC addresses to node addresses) using this MAC address buffer and linking it to the node's address contained in the OGM. A node that wants to contact a client has to lookup the node the client is connected to and its address in the global translation table. It is easy to understand that this implementation suffers from several issues: - big overhead (each and every OGM contains the entire list of connected clients) - high latencies for client route updates due to long OGM trip time and OGM losses The new implementation addresses these issues by appending client changes (new client joined or a client left) to the OGM instead of filling it with all the client addresses each time. In this way nodes can modify their global tables by means of "updates", thus reducing the overhead within the OGMs. To keep the entire network in sync each node maintains a translation table version number (ttvn) and a translation table checksum. These values are spread with the OGM to allow all the network participants to determine whether or not they need to update their translation table information. When a translation table lookup is performed in order to send a packet to a client attached to another node, the destination's ttvn is added to the payload packet. Forwarding nodes can compare the packet's ttvn with their destination's ttvn (this node could have a fresher information than the source) and re-route the packet if necessary. This greatly reduces the packet loss of clients roaming from one AP to the next. Signed-off-by: Antonio Quartulli <ordex@autistici.org> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Sven Eckelmann <sven@narfation.org>
65 lines
2.8 KiB
C
65 lines
2.8 KiB
C
/*
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* Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
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*
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* Marek Lindner, Simon Wunderlich
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*
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*/
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#ifndef _NET_BATMAN_ADV_TRANSLATION_TABLE_H_
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#define _NET_BATMAN_ADV_TRANSLATION_TABLE_H_
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int tt_len(int changes_num);
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int tt_changes_fill_buffer(struct bat_priv *bat_priv,
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unsigned char *buff, int buff_len);
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int tt_init(struct bat_priv *bat_priv);
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void tt_local_add(struct net_device *soft_iface, const uint8_t *addr);
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void tt_local_remove(struct bat_priv *bat_priv,
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const uint8_t *addr, const char *message);
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int tt_local_seq_print_text(struct seq_file *seq, void *offset);
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void tt_global_add_orig(struct bat_priv *bat_priv,
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struct orig_node *orig_node,
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const unsigned char *tt_buff, int tt_buff_len);
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int tt_global_add(struct bat_priv *bat_priv,
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struct orig_node *orig_node, const unsigned char *addr,
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uint8_t ttvn);
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int tt_global_seq_print_text(struct seq_file *seq, void *offset);
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void tt_global_del_orig(struct bat_priv *bat_priv,
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struct orig_node *orig_node, const char *message);
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void tt_global_del(struct bat_priv *bat_priv,
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struct orig_node *orig_node, const unsigned char *addr,
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const char *message);
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struct orig_node *transtable_search(struct bat_priv *bat_priv,
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const uint8_t *addr);
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void tt_save_orig_buffer(struct bat_priv *bat_priv, struct orig_node *orig_node,
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const unsigned char *tt_buff, uint8_t tt_num_changes);
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uint16_t tt_local_crc(struct bat_priv *bat_priv);
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uint16_t tt_global_crc(struct bat_priv *bat_priv, struct orig_node *orig_node);
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void tt_free(struct bat_priv *bat_priv);
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int send_tt_request(struct bat_priv *bat_priv,
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struct orig_node *dst_orig_node, uint8_t hvn,
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uint16_t tt_crc, bool full_table);
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bool send_tt_response(struct bat_priv *bat_priv,
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struct tt_query_packet *tt_request);
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void tt_update_changes(struct bat_priv *bat_priv, struct orig_node *orig_node,
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uint16_t tt_num_changes, uint8_t ttvn,
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struct tt_change *tt_change);
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bool is_my_client(struct bat_priv *bat_priv, const uint8_t *addr);
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void handle_tt_response(struct bat_priv *bat_priv,
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struct tt_query_packet *tt_response);
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#endif /* _NET_BATMAN_ADV_TRANSLATION_TABLE_H_ */
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