Re: linux-lora.git and LoRaWAN (was: [RFC net-next 00/15] net: A socket API for LoRa) - Jian-Hong Pan

From: Jian-Hong Pan <starnight@g.ncu.edu.tw>
To: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: "Andreas Färber" <afaerber@suse.de>,
	"Ben Whitten" <Ben.Whitten@lairdtech.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"<linux-arm-kernel@lists.infradead.org\\"
	<linux-arm-kernel@lists.infradead.org>,
	"Jan Jongboom" <jan.jongboom@arm.com>,
	"Konstantin Böhm" <konstantin.boehm@ancud.de>,
	"Ken Yu" <ken.yu@rakwireless.com>,
	"Dollar Chen" <dollar.chen@wtmec.com>,
	"Michael Röder" <michael.roeder@avnet.eu>,
	"Janus Piwek" <jpiwek@arroweurope.com>,
	"Matthias Brugger" <mbrugger@suse.com>,
	"S. Miller" <davem@davemloft.net>,
	"linux-kernel@vger.kernel.org>," <contact@snootlab.com>,
	"Brian Ray" <brian.ray@link-labs.com>
Subject: Re: linux-lora.git and LoRaWAN (was: [RFC net-next 00/15] net: A socket API for LoRa)
Date: Sun, 5 Aug 2018 22:08:10 +0800	[thread overview]
Message-ID: <CAC=mGzgW2fmRAA9GxojcbiBWm_G=rWqFh2MZECu-VST20MePBg@mail.gmail.com> (raw)
In-Reply-To: <20180803150258.791b9942@alans-desktop>

Hi Alan,

2018-08-03 22:02 GMT+08:00 Alan Cox <gnomes@lxorguk.ukuu.org.uk>:
>> I'm not yet too deep into LoRaWAN, but from the AT command interfaces
>> I've seen there's confirmed and unconfirmed transmission modes that with
>> PF_LORAWAN might be mapped to SOCK_STREAM and SOCK_DGRAM. Or do you see
>> a way of doing both on a single PF_LORA SOCK_LORAWAN socket?
>
> SOCK_STREAM is not a confirmed message, but a reliable data stream where
> packet boundaries have no meaning.
>
> SOCK_SEQPACKET is a reliable ordered stream where message boundaries have
> meaning.
>
> SOCK_RDM is reliable messaging where there is no ordering.
>
> The standard socket API has no concept of a single connection doing both
> reliable and unreliable messages.

Thanks for the useful information.

LoRaWAN has 4 kinds of data messages: Unconfirmed data up/down,
Confirmed data up/down.

Unconfirmed data up/down can be mapped to SOCK_DGRAM.
Confirmed data up/down can be mapped to SOCK_SEQPACKET.  Because,
there is the FCnt (frame counter) field in frame header for the order.

Regards,
Jian-Hong Pan

>> Additionally I've been looking into socket options at PF_LORA dgram
>> layer for some radio options, but discarded that again for lack of
>> precedence. Basically I wondered whether we could allow to choose SF,
>
> I don't know if it'll stretch that far in the right directions but to the
> extent you can re-use bits of the wifi API and it makes sense it would be
> good to do so.
>
> For stuff bound to a specific socket you need to use the generic SOCK_
> stuff or you may indeed need some socket options at the PF_LORA level -
> which is fine, and the whole point of setsockopt passing layers around.
>
> Some of the existing general stuff like priority is probably quite
> useable.
>
>> bandwidth, etc. on socket level and then apply those settings before
>> sending one packet rather than expecting a global netlink operation that
>> affects all sockets for that interface.
>
> Alan