Subject: |
Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address |
From: |
William Kirstaedter via Tech-talk <tech-talk at aps.anl.gov> |
To: |
EPICS Tech Talk <tech-talk at aps.anl.gov> |
Date: |
Wed, 8 Jun 2022 11:00:19 +0200 |
I have a follow-up question in this matter.
as far as I understand, the recceiver takes the messages of the
reccasters and stores them in an sqlite file.
how does the channelfinder java software access this information?
I'd like to run two instances of the recceiver and only one
channelfinder.
it doesnt seem to be documented or I couldnt find it.
thanks in advance,
- W
Am 25.04.2022 um 17:11 schrieb Michael
Davidsaver:
On
4/25/22 06:56, William Kirstaedter via Tech-talk wrote:
TL;DR: it now works with Heinz'
suggestion:
longer explanation:
we have multiple small labs with own, dedicated networks, that
NAT outgoing traffic.
but, all of them utilize the same private network: 10.0.0.0/23,
since I set them up via script.
so routing is not an option.
I think this is only the case if you also lack administrative
control
of both the IP routers involved.
next idea was to translate the recceivers
broadcast signal into the private lab network, via iptables,
kind of a reverse NAT if you will.
but as it turned out, iptables doesnt handle broadcast packets
so I switched to socat which does.
Maybe stating the obvious, but recceiver (like CA/PVA) can be
configured to send to unicast addresses.
So eg. the same tricks for routing CA searches / beacons will also
work with recsync.
https://epics-controls.org/resources-and-support/documents/howto-documents/configure-channel-access/
In particular, when you have admin access on hosts, but not
routers, this can be
a solution.
https://epics-controls.org/resources-and-support/documents/howto-documents/channel-access-reach-multiple-soft-iocs-linux/
since the reccasters in the IOCs only
respond to the address in the 16byte message, the response never
got through...
but now, with the correct and dedicated IP of the channelfinder
server in it, it works perfectly. :)
by the way: FF FF FF FF as an IP address doesnt make sense to me
anyways.
in my eyes, the reccaster should either broadcast its first IP
address or a configured one?
Think about how this would work on a computer with multiple
network interfaces.
You could end up with one IP in the recsync packet, and having the
OS put
another in the IP header. This used to happen with RSRV, and
caused problems
with some network topologies. The fix was to send 0xffffffff
instead of a
specific IP.
- William
William Kirstaedter (PP&B) Fritz-Haber-Institut der MPG
Faradayweg 4-6 14195 Berlin
Tel: 030 8413 5405 Mail: kirstaedter at fhi-berlin.mpg.de
Am 25.04.2022 um 13:01 schrieb Heinz Junkes via Tech-talk:
Hallo Han,
thanks for the hint. But this only works if the computer
system also has a “leg” (network connection) into the
respective networks?
We also have something like this for the FEL network, for
example. But otherwise there are always gateway computers
between the individual experiment networks und the main-net.
However, since we are routing out of the experiment machines
into our main-net, I'll try my hand at modifying announce.py.
tcpaddr='\xff\xff\xff\xff’ -> tcpaddr='\x8d\x0e\x8c\x62’
(141.14.140.98)
Heinz
On 24. Apr 2022, at 02:43, Han
Lee<jeonglee at lbl.gov> wrote:
Hi Heinz,
Could you try to add your IOC address subnets into the
recceiver server configuration as addr_list?
https://github.com/jeonghanlee/RecSync-env/blob/7b9fbc794ec8e4ae36349593780f9dcd00d142a0/site-template/recsync.conf.in#L16
Multiple IOCs just see the resync server (Not CF -
elasticsearch - server) without issues.
For example, you can add each subnet where your IOCs are
running, such as
10.10.11.255:5049, 10.10.48.255:5049,
..................................
I hope this is what you are looking for. Or I completely
misunderstand your description.
Best,
Han
On Fri, Apr 22, 2022 at 11:52 AM Heinz Junkes via
Tech-talk<tech-talk at aps.anl.gov> wrote:
Hi,
we need to route the announcements from our central
Channelfinder server to a subnet so that the
recasters on the IOCs in the subnet can send their PV
information to the server.
Unfortunately, the announcement package does not contain the
IP of the server but FF:FF:FF:FF.
root@priscilla:~# socat -ls -u -v -x
UDP4-RECVFROM:5049,broadcast,fork,bind=141.14.143.255
UDP4-SENDTO:10.0.1.255:5049,broadcast
2022/04/22 17:22:18.879313
length=16 from=0 to=15
52 43 00 00 ff ff ff ff 84 81 00 00 61 bf c1 23
RC..........a..#
Gruss Heinz
--
Jeong Han Lee, Dr.rer.nat
Staff Scientist and Engineer
Lawrence Berkeley National Laboratory
1 Cyclotron Road Mailstop 46R0161
Berkeley, CA 94720, United States
Tel :+1-510-486-6163
Cell:+1-510-384-3868
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- References:
- Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Heinz Junkes via Tech-talk
- Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Han Lee via Tech-talk
- Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Heinz Junkes via Tech-talk
- Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address William Kirstaedter via Tech-talk
- Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Michael Davidsaver via Tech-talk
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