On 07/11/17 22:16, Harald Welte wrote:
On Tue, Nov 07, 2017 at 12:36:03PM +0100, Pau Espin Pedrol wrote:
Hi,
I see the range for ipa unit-d site_id range of values is 0-65534 as
configured in the VTY:
osmo-bts/src/common/vty.c
397: "ipa unit-id <0-65534> <0-255>",
osmo-bsc/src/libbsc/bsc_vty.c
1850: "ip.access unit_id <0-65534> <0-255>",
openbsc/openbsc/src/libbsc/bsc_vty.c
1803: "ip.access unit_id <0-65534> <0-255>",
osmo-bts/src/common/vty.c
397: "ipa unit-id <0-65534> <0-255>",
However, being it a uint16_t having 2^16=65536 values, I would expect the
range to be 0-65535 (finished in 5, not 4). The only reason I can think of
is that the last address is somehow reserved and must not be used. Does
somebody know if that's the case? I couldn't find any documentation and as
far as I can tell our code doesn't seem to handle the site_id=65535 case
specially. If it is not reserved, then I can send a patch to change the
range to be 0-65535.
I don't actually know, as we don't know what ip.access' thoughts were when
designing this. There mihgt be something we forgot. I'd vote to keep as-is
as it doesn't hurt to have one less unit id vs. the risk to break some setup.
$ ag "0-65534"
libosmocore/src/gb/gprs_ns_vty.c
269: "nse <0-65535> nsvci <0-65534>",
osmo-sgsn/src/gprs/gb_proxy_vty.c
149: "sgsn nsei <0-65534>",
364: "secondary-sgsn nsei <0-65534>",
532: "delete-gbproxy-peer <0-65534> bvci <2-65534>",
553: "delete-gbproxy-peer <0-65534> (only-bvc|only-nsvc|all) [dry-run]",
626: "delete-gbproxy-link <0-65534> (tlli|imsi|sgsn-nsei) IDENT",
698: "delete-gbproxy-link <0-65534> (stale|de-registered)",
I cannot find any reference in 08.14 or 01.16 to why NSVCI 0xffff is reserved,
so it could be changed
After having a quick deeper look, I saw the following written in
libosmocore/src/gb/gprs_ns.c:53
* This implementation has the following limitations:
* - Only one NS-VC for each NSE: No load-sharing function
* - NSVCI 65535 and 65534 are reserved for internal use
And I see several checks against 0xff and 0xfe in the code playing with
dummy ids. I guess it's worth looking at it, because we should then
either remove use of 65534 or try to fix the implementation and provide
the 2 ports missing. But I agree it's probably not a high priority.
--
- Pau Espin Pedrol <[email protected]> http://www.sysmocom.de/
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