Hi Manfred,
I just stumbled over the IP address you are using (239.255.255.250). If
I remember correctly this is a IPv4 Class D Multicast address.
(224.0.0.0-239.255.255.255).
So if you want to transmit datagrams to this IP address or recieve
datagrams sent to this multicast groups you have to set appropriate IP
Options.
You can set this options using Socket>>#setOption:value: and read them
using Socket>>#getOption:. Please note that both methods expect the
option to set as a name - not as constant. E.g.
socket setOption: 'IP_MULTICAST_IF' value: multicastInterface.
If I do remember correctly you have to set the following options for
sending/receiving:
Sending:
IP_MULTICAST_IF
(IP_MULTICAST_LOOP)
(IP_MULTICAST_TTL)
Sending should AFAIK work w/o setting any option - although
IP_MULTICAST_IF is highly recommended.
Receiving:
(SO_REUSEADDR)
IP_ADD_MEMBERSHIP
(IP_DROP_MEMBERSHIP)
Receiving only works if you joined the multicast group previously. So I
assume that you need to do something like this (not tested).
imrMultiaddr := #[239 255 255 250].
imrInterface := #[0 0 0 0].
ipMreq := imrMultiaddr , imrInterface.
socket setOption: 'MEMBERSHIP' value: ipMreq.
Hope this helps.
CU,
Udo
On 18/05/15 16:34, Manfred Kröhnert wrote:
Hi Sven,
On Mon, May 18, 2015 at 4:14 PM, Sven Van Caekenberghe
<s...@stfx.eu
<mailto:s...@stfx.eu>> wrote:
> On 18 May 2015, at 15:47, Manfred Kröhnert
<mkroehner...@googlemail.com
<mailto:mkroehner...@googlemail.com>> wrote:
>
> Hi,
> apparently I am missing something else.
>
> I can find devices when connected to a 'regular' LAN.
>
> However, I have a camera that creates a Wifi accesspoint and
makes itself discoverable via SSDP.
> Once I connect to this accesspoint my computer gets a valid IP
address assigned and the NodeJS code is able to discover the device.
> Unfortunately, the Pharo snippet I posted before does not give me
any results and hangs in Socket>>waitForDataIfClosed: .
>
> Any further ideas?
Are you sure you restarted the image and your code after switching
networks ?
I did not check this before.
But I just downloaded a fresh 40613 image with PharoLauncher and started
it after connecting to the camera accesspoint.
The code snippet freezes there as well.
Manfred
