Before this patch, the free CID with the smallest number was always
selected to be used. This caused more or less the same subset of CIDs to
be used all the time, while the CIDs with bigger numbers were mostly
unused.
Let's distribute the use so that all CIDs are used roughly the same.
This has the advantage, among others, that the same CID will not be
re-used immediatelly after being freed if a new call is established.
It is useful to leave the CIDs unused for some time since the other end
peer may know of the call being tear down with some delay.
Hence if a new call is established immediately after the CID was
released, the same CID would be allocated and passed at the peer, which
would then detect that the old call (in its view still active) would
already make use of that remote CID.
Related: SYS#6161
Change-Id: I72803fb172accbabfc81923572890f8ecb06cefd
Lchans which are marked as non-connected have not yet received
information about its remote peer, hence they may not have some fields
available yet. Let's skip them to avoid accessing such fields
(lchan->abis_ip.osmux.in).
Related: SYS#5987
Change-Id: Id53822c4a0486b0090df2db3d185e047d14fc90a
This is actually quite common, since our peer may be sending some osmux
packets to us a while after we have closed the conn on our side,
specially if latency is high in the network (eg satellite links).
Related: SYS#598
Change-Id: I102047685b9b9f4cba43970945f955c4fe9c4c95
This way we have no more access to internal osmux structures.
If those counters are needed in the future they can be counted by
osmo-bts by means of adding rate counters to the caller of
osmux_xfrm_input() and deliver_cb.
Change-Id: Ib952437ea3aa2770c96bddb667491e7675a6a06e
Pau Espin