Bug #5186
closedlocal-ip config parameter can cause unclear behaviour on dual IP stack system
100%
Description
keyphrase from osmo-bsc log for search engines:
DLSS7 ERROR m3ua.c:507 XUA_AS(as-clnt-A-0-m3ua) {AS_DOWN}: Event AS-TRANSFER.req not permitted
In osmo-stp.cfg we have typically have something like:
cs7 instance 0 xua rkm routing-key-allocation dynamic-permitted route-table system listen m3ua 2905 local-ip :: accept-asp-connections dynamic-permitted
This is actually fine.
But, the configuration VTY tells us:
OsmoSTP(config-cs7-listen)# local-ip A.B.C.D IPv4 Address to use for XUA X:X::X:X IPv6 Address to use for XUA
and so the user might think, ah OK I want to use 127.0.0.1 resulting in a config of
cs7 instance 0 xua rkm routing-key-allocation dynamic-permitted route-table system listen m3ua 2905 local-ip 127.0.0.1 accept-asp-connections dynamic-permitted
Actually local-ip 0.0.0.0 will also trigger this issue.
Now let's start osmo-bsc and osmo-msc with the minimal configuration files needed to start up, leaving the rest to default values for the sake of clarify here, although this issue can be observed with a fully configured BSC/MSC:
osmo-bsc.cfg:
msc 0 mgw remote-ip 127.0.0.1
osmo-msc.cfg:
BLANK - Use all defaults.
osmo-bsc will constantly log: Event AS-TRANSFER.req not permitted
although osmo-bsc vty will show:
OsmoBSC# show msc 0 m3ua RI=SSN_PC,PC=0.23.3,SSN=BSSAP RI=SSN_PC,PC=0.23.1,SSN=BSSAP
osmo-msc vty will show:
OsmoMSC# show bsc OsmoMSC#
So one should NOT use an ipv4 address in local-ip, UNLESS ipv6 stack is disabled with:
sysctl net.ipv6.conf.all.disable_ipv6=1
If you have OSMO-STP config with an IPv4 address in local-ip, as soon as you disable the ipv6 stack, you'll see:
[other log messages leading up to...] DMSC NOTICE (msc0) BSSMAP assocation is up
To confirm:
with local-ip ::
there's no problem with ipv4/ipv6 being enabled or not.
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