osmocom-net-gprs September 2017

osmocom-net-gprs@lists.osmocom.org

10 participants
10 discussions

Current osmo-pcu patch set
by Holger Freyther 05 Oct '17

05 Oct '17

Hi, I am a bit lost with the review of the current osmo-pcu patchset. Going through the patches I have difficulties to see the red thread and what is better after we integrate the changes. I guess the goal is to add the allocation of multiple uplink timeslots but from my point of view this is buried in a lot of subjective sideway development. My wish would be: For multiple slot UL allocation: Make the most direct patchset to implement this feature. I understand that to avoid code duplication some methods can be re-used but instead of having 10 patches that change int->bool, change signatures of functions, maybe make it minimal to see how it works first? After it works send a cover mail that explains what and why you took the approach, what the _speed_ improvement for browsing is or when it is being used. What you see the danger in terms of common ts and allocation. For the clean-ups: I don't say we shouldn't do them but we should do them in a way they don't take much time to review and still provide a net gain to the contributor. A "cosmetic" patch that breaks the build is very suspicious and forces a reviewer to look extra carefully into these "clean-ups". int->bool: I think int->bool and 1->true adds little value for an application but if it is important then please do it by semantic patching so they can be easily reviewed. bts->trx: I think there is little value to change a function signature from getting a BTS to a TRX when the implementation starts to do: - bts->list + trx->bts->list "API" documentation: Comments can be helpful and it is good to explain on a high level what a function will do and what the side-effects will be. But in an application I think writing: \param[in,out] bts Pointer to BTS struct adds not enough value. First it is wrong as the type is not "BTS" but it is the "C" gprs_rlcmac_bts. And second doxygen will perfectly tell you the type of of the parameter anyway. Documenting that -1 of a parameter has a specific semantic can have some advantage but the risk of code/doc not agreeing is there as well. libosmocore: We do have a desire for reuse but everytime you make osmo-pcu depend on a unreleased version of libosmocore rebuilding osmo-pcu get's more difficult and the compile error is not obvious. It is not clear where the macro is coming from. So please keep this in mind and try to find a balance. thank you for your consideration holger

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HEADS UP: stricter VTY, possible config fallout
by Neels Hofmeyr 21 Sep '17

21 Sep '17

Hi all, we have recently merged a profound change to the inner workings of the VTY configuration. We've hit some fallout due to that, hence I would like to let you know that you might hit the same. The VTY parsing of config files is now strict about indenting. A child node *must* be indented below the parent node, and indenting must be consistent. For more details on the reason why and a definition of 'consistent', see the commit log of https://git.osmocom.org/libosmocore/commit/?id=4a31ffa2f0097d96201f80305a04… So, if you are in the near future faced with config files being rejected that worked perfectly before, it is most probably because your indenting was wrong all the time, and only now did we start checking it. If the cause is hard to figure out, a good aid is the telnet VTY, where you may either 'show running-config' or traverse the nodes manually to query which command exists on which level. If your current config is broken, you may be able to start the program with an empty or stripped down config file to make its telnet available. The above is about reading config files, but we have also dropped the implicit 'exit' to parent level on the telnet VTY console. This caused fallout where nodes by plain omission lack the 'exit' command: one is unable to leave such a node once it is entered. That is a fault in the program's VTY setup that was not found before, because the VTY would often just find the parent node's exit command instead. I have a patch to avoid all of these everywhere, by installing the exit and end commands automatically for every VTY node that gets created; it is not merged yet: https://gerrit.osmocom.org/3998 ------ Config Fallout Example ------ For example, we hit a breakage with this osmo-bts-trx.cfg: phy 0 instance 0 osmotrx rx-gain 25 osmotrx tx-attenuation oml osmotrx ip local 10.23.42.1 osmotrx ip remote 10.23.42.2 Before, this worked perfectly. Now it says the command 'osmotrx rx-gain' does not exist. The reason is that 'osmotrx rx-gain' is a child node of 'instance 0'. The first fix looked like this: phy 0 instance 0 osmotrx rx-gain 25 osmotrx tx-attenuation oml osmotrx ip local 10.23.42.1 osmotrx ip remote 10.23.42.2 But alas, this time it said the command 'osmotrx ip local' does not exist. I suspected bugs in the new parsing, but indeed, 'osmotrx ip' is actually a direct child of the 'phy 0' level. Before, the VTY would implicitly step out of a child level if it found a matching command one parent above. That is confusing in other situations (see above commit log), hence we now require indenting to clarify the structure. This is the correct one: phy 0 instance 0 osmotrx rx-gain 25 osmotrx tx-attenuation oml osmotrx ip local 10.23.42.1 osmotrx ip remote 10.23.42.2 Or rephrased: phy 0 osmotrx ip local 10.23.42.1 osmotrx ip remote 10.23.42.2 instance 0 osmotrx rx-gain 25 osmotrx tx-attenuation oml To query the structure via telnet, I did: $ ./osmo-bts/src/osmo-bts-trx/osmo-bts-trx -c osmo-bts/doc/examples/trx/osmo-bts.cfg $ telnet localhost 4241 OsmoBTS> enable OsmoBTS# configure terminal OsmoBTS(config)# phy 0 OsmoBTS(phy)# list [...] osmotrx ip HOST osmotrx ip (local|remote) A.B.C.D [...] OsmoBTS(phy)# inst OsmoBTS(phy)# instance 0 OsmoBTS(phy-inst)# list [...] osmotrx rx-gain <0-50> osmotrx tx-attenuation <0-50> osmotrx tx-attenuation oml [...] ------ No Exit Example ------ The same osmo-trx VTY nodes also show the exit failure: $ telnet localhost 4241 OsmoBTS> enable OsmoBTS# configure terminal OsmoBTS(config)# phy 0 OsmoBTS(phy)# exit % Unknown command. OsmoBTS(phy)# instance 0 OsmoBTS(phy-inst)# exit % Unknown command. On the phy level, we would previously find the parent's 'exit' command, but in the 'instance' level, 'exit' has never been available. Above patch should fix all of these. ~N -- - Neels Hofmeyr <nhofmeyr(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschäftsführer / Managing Directors: Harald Welte

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Kernel patchset for IPv6 support on netdev mailinglist
by Harald Welte 19 Sep '17

19 Sep '17

Hi all! Just in case anyone here is intrerested, I'd like to point out that a recent patch series for IPv6 (and other feature) support of the Linux kernel GTP-U code has been posted to the linux-netdev list and is under review/discussion there: https://www.spinics.net/lists/netdev/msg455286.html Please follow-up with any review comments there. Thanks! -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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回复：Re: Unable to access git repository
by lokira 19 Sep '17

19 Sep '17

Hi Holger, It's working now!Thanks for the quick fix! Regards, WangSS

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Unable to access git repository
by lokira 19 Sep '17

19 Sep '17

Hello, I was trying to clone git repository from http://git.osmocom.org/libgtpnl/but got an error : remote: An error occurred while reading CGI reply (no response received)fatal: unable to access 'http://git.osmocom.org/libgtpnl/': The requested URL returned error: 502 I can't open http://git.osmocom.org/libgtpnl/ in browser either. It said 'An error occurred while reading CGI reply (no response received)'. Is my url to git repository wrong ? Thanks, WangSS

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Update and Question
by fırat sönmez 18 Sep '17

18 Sep '17

Hi, I want to ask two questions. I dont know if you remember, but I have been trying to backport GTP to 3.18 kernel. I fixed all the errors, it works. However there is one issue that I'm not sure how to implement it correctly. --->There is one private flag called IFF_NO_QUEUE and it has no implemetation in 3.18 kernel, I just set it to an unused bit in the private flag field. I would like to get your opinion on this. *include/linux/netdevice.h ->(*@IFF_NO_QUEUE: device can run without qdisc attached*) The other thing I would like to ask is that I cannot reach the git repository for libgtpnl. Could you please check it? Thanks, Fırat

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Unable to start osmo-ggsn with -g or --gtp-linux options
by Ravi Tandon 14 Sep '17

14 Sep '17

Hello, I compiled osmo-ggsn and was trying to run it as per the instructions present on https://osmocom.org/projects/openggsn/wiki/Kernel_GTP But when I try to start osmo-ggsn *using -g or --gtp-linux*, it says invalid option. Please let me know how to start it using gtp kernel. I have modprobed gtp.ko successfully. [root@localhost osmo-ggsn]# lsmod |grep gtp gtp 28672 0 ip6_udp_tunnel 16384 1 gtp udp_tunnel 16384 1 gtp [root@localhost examples]# osmo-ggsn --gtp-linux -c osmo-ggsn.cfg -d *osmo-ggsn: unrecognized option '--gtp-linux'* <0002> ggsn.c:159 APN(internet): Starting <0002> ggsn.c:162 APN(internet): Opening TUN device tun4 <0002> ggsn.c:167 APN(internet): Opened TUN device tun4 <0002> ggsn.c:178 APN(internet): Setting tun IP address 176.16.222.0/24 <0002> ggsn.c:224 APN(internet): Creating IPv4 pool 176.16.222.0/24 <0002> ggsn.c:245 APN(internet): Successfully started <0002> ggsn.c:159 APN(inet6): Starting <0002> ggsn.c:162 APN(inet6): Opening TUN device tun6 <0002> ggsn.c:167 APN(inet6): Opened TUN device tun6 <0002> ggsn.c:190 APN(inet6): Setting tun IPv6 address 2001:780:44:2000::/56 <0002> ggsn.c:236 APN(inet6): Creating IPv6 pool 2001:780:44:2000::/56 <0002> ggsn.c:245 APN(inet6): Successfully started <0002> ggsn.c:159 APN(inet46): Starting <0002> ggsn.c:162 APN(inet46): Opening TUN device tun46 <0002> ggsn.c:167 APN(inet46): Opened TUN device tun46 <0002> ggsn.c:178 APN(inet46): Setting tun IP address 176.16.46.0/24 <0002> ggsn.c:190 APN(inet46): Setting tun IPv6 address 2001:780:44:2100::/56 <0002> ggsn.c:224 APN(inet46): Creating IPv4 pool 176.16.46.0/24 <0002> ggsn.c:236 APN(inet46): Creating IPv6 pool 2001:780:44:2100::/56 <0002> ggsn.c:245 APN(inet46): Successfully started <0002> ggsn.c:687 GGSN(ggsn0): Starting GGSN <000d> gtp.c:705 GTP: gtp_newgsn() started at 192.168.11.128 <0002> ggsn.c:724 GGSN(ggsn0): Successfully started <0005> telnet_interface.c:102 telnet at 127.0.0.1 4260 <000c> control_if.c:788 CTRL at 127.0.0.1 4257 Also, I tried executing gtp-tunnel list but it gives empty output. [root@localhost tools]# ./gtp-tunnel list [root@localhost tools]# Please help. Thanks, Ravi <https://osmocom.org/projects/openggsn/wiki/Kernel_GTP>

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OsmoGGSN succeeds OpenGGSN!
by Harald Welte 06 Sep '17

06 Sep '17

Hi all, 12 years after OpenGGSN was seemingly abandoned by its original creators, and 7 years after Osmocom adopted it, it is time for a significant change: OpenGGSN is becoming a first-class Osmocom citizen called OsmoGGSN. We had already taken some baby-steps in the past by introduction of a CTRL interface as well as the use of libosmocore logging. However, my recent patches introducing a VTY interface and changing the configuration file format from the 'gengetopt' style to libosmovty based change the look+feel of the program significantly that it is a good point to rename. After all, if command-line arguments and config file syntax are changing, documentation will also need to change and it becomes confusing to users to understand that depending on the version the documentation is correct or incorrect. So from today on, * osmo-ggsn is available from http://git.osmocom.org/osmo-ggsn/ * osmocom:nightly packages will build both openggsn + osmo-ggsn * osmocom:nitb-split:nightly packages will only build osmo-ggsn * redmine still at http://osmocom.org/projects/openggsn due to permanent redmine project naming... The introduction of the VTY interface comes with many new possibilities, such as * multiple GGSN instances bound to different GTP IP addresses * multiple APNs within each GGSN, each with different Address Pools and tun-devices * sophisticated logging configuration (syslog, file, stdout, telnet) What's still missing: * re-integrate kernel GTP-U support * create OsmoGGSN user manual in osmo-gsm-manuals.git * migrate TTCN-3 test execution on jenkins to osmo-ggsn * perl/python script to convert old config file to new config file format (any volunteers?) Roadmap: * IPv6 transport plane support (outer IP layer surrounding GTP/UDP) * improved logging (ensure context is always included) * libgtp: migration of kernel GTP-U support into libgtp (not just ggsn) * libgtp: make PDP context hash table part of the 'gsn' structure * once all expected ABI/API changes are done, rename libgtp to libosmo-gtp In terms of maintenance, I don't want to continue to maintain OpenGGSN for much longer. We'll keep it around for some time and merge important security and/or bug fixes, but I won't accept new feature patches into OpenGGSN. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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GTP-C v2 in open grps
by Tom Herbert 04 Sep '17

04 Sep '17

Hello, I am a newbie in this area so please pardon me if these are dumb or covered questions! I am looking for a GTP stack that implements GTP-C version 2. Is this supported in open grps or is there a plan for that? If not, what stack (preferably open source) is recommended? Thanks, Tom

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RFC: OpenGGSN split/rename
by Max 03 Sep '17

03 Sep '17

Hi. With the ongoing split of OpenBSC into per-project repository, I wonder if we could do the same to OpenGGSN and split libgtp into separate repository? Rationale: * would simplify docs for newcomers (it's not obvious that openggsn have to be built ahead of OsmoSGSN because of libgtp) * simplify release process (we can release libgtp independently of OpenGGSN, makes it easier to automate too) While at it and considering recent IPv6 support (and related config changes) it might be also good idea to rename it to OsmoGGSN (and libosmo-gtp?) to clearly mark the breaking point. What do you think? -- Max Suraev <msuraev(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Alt-Moabit 93 * 10559 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Director: Harald Welte

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osmocom-net-gprs September 2017