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>
47 lines
1.5 KiB
C
47 lines
1.5 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_AGGREGATION_H_
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#define _NET_BATMAN_ADV_AGGREGATION_H_
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#include "main.h"
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/* is there another aggregated packet here? */
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static inline int aggregated_packet(int buff_pos, int packet_len,
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int tt_num_changes)
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{
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int next_buff_pos = buff_pos + BAT_PACKET_LEN + (tt_num_changes *
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sizeof(struct tt_change));
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return (next_buff_pos <= packet_len) &&
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(next_buff_pos <= MAX_AGGREGATION_BYTES);
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}
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void add_bat_packet_to_list(struct bat_priv *bat_priv,
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unsigned char *packet_buff, int packet_len,
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struct hard_iface *if_incoming, int own_packet,
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unsigned long send_time);
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void receive_aggr_bat_packet(const struct ethhdr *ethhdr,
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unsigned char *packet_buff, int packet_len,
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struct hard_iface *if_incoming);
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#endif /* _NET_BATMAN_ADV_AGGREGATION_H_ */
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