[PD] UDP server with Pd

[Christof Ressi]

Great to hear!

On 07.06.2021 22:57, Martin Peach wrote:
> So I changed it to use sendto and it works a lot better. It receives
> from multiple clients while sending to any one.
> I added a [to ( message to set the destination, and removed the
> [connect( and [disconnect{ methods.
> Thanks Christof for the critique!.
>
> Martin
>
> On Mon, Jun 7, 2021 at 4:02 PM Christof Ressi <info at christofressi.com> wrote:
>>> The only problem I see with it is that while the socket is connected
>>> for a send, it won't receive anything.
>> Why is that? This shouldn't happen.
>>
>> BTW, you don't actually have to call connect(), instead you could just
>> save the sockaddr and use sendto(). Consequently you could also rename
>> the [connect( method to something else, e.g. [set <host> <port>( or
>> [client <host> <port>(, etc. After all, a server doesn't *connect* to a
>> client...
>>
>> Christof
>>
>> On 07.06.2021 21:34, Martin Peach wrote:
>>> OK, I have implemented something that might work: [udpsrvr] can listen
>>> on a port and send to an address using the same or a different port.
>>> The only problem I see with it is that while the socket is connected
>>> for a send, it won't receive anything. I overcome this partly by
>>> sending the connect/send/disconnect sequence in one comma-delimited
>>> message.
>>> The code is at
>>> https://sourceforge.net/p/pure-data/svn/HEAD/tree/trunk/externals/mrpeach/net/udpsrvr.c
>>>
>>> Martin
>>>
>>> On Mon, Jun 7, 2021 at 3:48 AM Roman Haefeli <reduzent at gmail.com> wrote:
>>>> On Sun, 2021-06-06 at 20:26 -0400, Martin Peach wrote:
>>>>> If you have a [udpreceive 9898] as your 'server' it will receive from
>>>>> anywhere on port 9898. So you can take the sender's ip and port from
>>>>> the latest incoming message (route 'from' at the second outlet) and
>>>>> use them to set the address and port of a single [udpsend] for the
>>>>> reply.
>>>>> There is no connection in udp so you need to add metadata in your
>>>>> datagrams for routing and so forth.
>>>> Again, this does not work. The socket on the client side will only
>>>> accept packets originating from the port it has sent packets to, but
>>>> [udpsend] on the server cannot use this port as bind port, because it
>>>> is already occupied by [udpreceive]. To put this into telephone
>>>> analogy: When you call someone, you expect a third party to be
>>>> prohibited from shouting into your call, and you expect to hear only
>>>> the party you called.
>>>>
>>>> The only solution to this is to use the same socket for both sending
>>>> and receiving, as Christof already suggested.
>>>>
>>>> Roman
>>>> _______________________________________________
>>>> Pd-list at lists.iem.at mailing list
>>>> UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list
>>>
>>> _______________________________________________
>>> Pd-list at lists.iem.at mailing list
>>> UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list