Commit Graph

6 Commits

Author SHA1 Message Date
Antonio Quartulli
8d2d499e08 batman-adv: ELP - send unicast ELP packets for throughput sampling
In case of an unused wireless link, the mac80211 throughput estimation
won't get updated further. Consequently, the reported throughput metric
will become obsolete.

With this patch unicast sampling is introduced by periodically sending
unicast ELP packets to each neighbor on idle WiFi links. These sampling
packets will fill an entire frame, so that the measurement is as
reliable as possible

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:25:07 +08:00
Antonio Quartulli
c833484e5f batman-adv: ELP - compute the metric based on the estimated throughput
In case of wireless interface retrieve the throughput by
querying cfg80211. To perform this call a separate work
must be scheduled because the function may sleep and this
is not allowed within an RCU protected context (RCU in this
case is used to iterate over all the neighbours).

Use ethtool to retrieve information about an Ethernet link
like HALF/FULL_DUPLEX and advertised bandwidth (e.g.
100/10Mbps).

The metric is updated each time a new ELP packet is sent,
this way it is possible to timely react to a metric
variation which can imply (for example) a neighbour
disconnection.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:25:06 +08:00
Antonio Quartulli
95d392784d batman-adv: keep track of when unicast packets are sent
To enable ELP to send probing packets over wireless links
only if needed, batman-adv must keep track of the last time
it sent a unicast packet towards every neighbour.

For this purpose a 2 main changes are introduced:
1) a new member of the elp_neigh_node structure stores the
   last time a unicast packet was sent towards this neighbour;
2) a wrapper function for sending unicast packets is
   implemented. This function will simply update the member
   describe din point 1) and then forward the packet to the
   real sending routine.

Point 2) implies that any code-path leading to a unicast
sending now has to use the new wrapper.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:05:32 +08:00
Antonio Quartulli
9323158ef9 batman-adv: OGMv2 - implement originators logic
Add the support for recognising new originators in the
network and rebroadcast their OGMs.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:05:31 +08:00
Linus Luessing
162bd64c24 batman-adv: ELP - creating neighbor structures
Initially developed by Linus during a 6 months trainee study
period in Ascom (Switzerland) AG.

Signed-off-by: Linus Luessing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
2016-02-29 16:05:30 +08:00
Linus Luessing
d6f94d91f7 batman-adv: ELP - adding basic infrastructure
The B.A.T.M.A.N. protocol originally only used a single
message type (called OGM) to determine the link qualities to
the direct neighbors and spreading these link quality
information through the whole mesh. This procedure is
summarized on the BATMAN concept page and explained in
details in the RFC draft published in 2008.

This approach was chosen for its simplicity during the
protocol design phase and the implementation. However, it
also bears some drawbacks:

 *  Wireless interfaces usually come with some packet loss,
    therefore a higher broadcast rate is desirable to allow
    a fast reaction on flaky connections.
    Other interfaces of the same host might be connected to
    Ethernet LANs / VPNs / etc which rarely exhibit packet
    loss would benefit from a lower broadcast rate to reduce
    overhead.
 *  It generally is more desirable to detect local link
    quality changes at a faster rate than propagating all
    these changes through the entire mesh (the far end of
    the mesh does not need to care about local link quality
    changes that much). Other optimizations strategies, like
    reducing overhead, might be possible if OGMs weren't
    used for all tasks in the mesh at the same time.

As a result detecting local link qualities shall be handled
by an independent message type, ELP, whereas the OGM message
type remains responsible for flooding the mesh with these
link quality information and determining the overall path
transmit qualities.

Developed by Linus during a 6 months trainee study period in
Ascom (Switzerland) AG.

Signed-off-by: Linus Luessing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
2016-02-29 16:05:29 +08:00