Experimental Physics and
Industrial Control System

Gerrit Kühn <[email protected]> · Thu, 24 Feb 2011 16:33:48 +0100

On Wed, 23 Feb 2011 12:08:12 -0700 "Jeff Hill" <[email protected]> wrote
about RE: epics on FreeBSD: broadcast problem:

JH> Make certain that the netmasks for the network interfaces in your
JH> FreeBSD system match the networks to which they are attached. See also
JH> the "Troubleshooting" portion of the CA reference manual.

They do. Actually this particular machine is serving as router and
dhcp-server for the subnet:

---
firefly1# ifconfig em1
em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC>
        ether 00:25:90:02:16:31
        inet 192.168.64.254 netmask 0xffffe000 broadcast 192.168.95.255
        media: Ethernet autoselect (1000baseT <full-duplex>)
        status: active
---

A Linux-system in the network looks quite the same:

---
psl@psl-fe4 ~ $ /sbin/ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:25:90:15:3e:16  
          inet addr:192.168.64.9  Bcast:192.168.95.255  Mask:255.255.224.0
          inet6 addr: fe80::225:90ff:fe15:3e16/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2994432254 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4677428405 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:277941608130 (258.8 GiB)  TX bytes:3767794266485 (3.4
TiB) Memory:d9020000-d9040000 
---

JH> If there are not routing issues, then I suspect that something is
JH> amiss with the code in EPICS base which we use to interrogate the
JH> broadcast address used by each network interface. 

There is no routing involved, all is happening inside this network.

JH> This code runs when
JH> EPICS_CA_AUTO_ADDR_LIST is YES. For POSIX, reference
JH> src/libCom/osi/os/default/osdNetIntf.c. We have occasionally needed to
JH> make some minor changes here before because socket library interface
JH> changes were not backwards compatible.

Even setting this explicitely to "YES" does not help:

---
firefly1# setenv | grep EPICS
EPICS_HOST_ARCH=freebsd-x86_64
EPICS_CA_AUTO_ADDR_LIST=YES
firefly1# ./caget G3:PSL-OSC_PZTVOLT
Channel connect timed out: 'G3:PSL-OSC_PZTVOLT' not found.
---

Only setting the broadcast directly does make it work:

---
firefly1# setenv | grep EPICS
EPICS_HOST_ARCH=freebsd-x86_64
EPICS_CA_AUTO_ADDR_LIST=YES
EPICS_CA_ADDR_LIST=192.168.95.255
firefly1# ./caget G3:PSL-OSC_PZTVOLT
G3:PSL-OSC_PZTVOLT             4.78195
---

JH> When running a soft IOC on this FreeBSD system, what does casr, with a
JH> high interest level (i.e. casr 100), show? There should be a list of
JH> network addresses listed there - which are the server's beacon
JH> destinations. When EPICS_CAS_AUTO_BEACON_ADDR_LIST is YES (the
JH> default) the code in src/libCom/osi/os/default/osdNetIntf.c is used to
JH> populate this list of beacon destination addresses.

---
epics> casr 100
Channel Access Server V4.13
No clients connected.
UDP Server:
UDP 0.0.0.0:0(): User="", V4.0, 0 Channels, Priority=0
        Task Id=0x80204f760, Socket FD=6
        Secs since last send   3.02, Secs since last receive   3.02
        Unprocessed request bytes=0, Undelivered response bytes=16
        State=up
        272 bytes allocated

        Send Lock
epicsMutexId 0x802236b80 source ../caservertask.c line 730
ownerTid 0x0 count 0 owned 0
        Put Notify Lock
epicsMutexId 0x802236b20 source ../caservertask.c line 731
ownerTid 0x0 count 0 owned 0
        Address Queue Lock
epicsMutexId 0x802236ac0 source ../caservertask.c line 732
ownerTid 0x0 count 0 owned 0
        Event Queue Lock
epicsMutexId 0x802236a60 source ../caservertask.c line 733
ownerTid 0x0 count 0 owned 0
        Block Semaphore
There are currently 1904 bytes on the server's free list
7 client(s), 0 channel(s), 0 event(s) (monitors) 0 putNotify(s)
0 small buffers (16384 bytes ea), and 0 jumbo buffers (16408 bytes ea)
The server's array size limit is 16408 bytes max
Channel Access Address List
10.15.254.2:5065
---

This last address belongs to some vpn connections the machine has, not to
the physical interfaces (em0 and em1). The IOC I actually want to talk to
sits on 192.168.64.9 and is reachable via em1.

cu
  Gerrit

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System