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* add gsm0808_cell_id_from_cgi(), gsm0808_cell_id_to_cgi()Neels Hofmeyr2019-03-086-8/+270
| | | | | | | | | | | | | | | | CGI to Cell ID: for example, for Paging, osmo-msc has a CGI for a subscriber and needs to send out a Cell Identifier IE. Makes sense to add this conversion here. Cell ID to CGI: for a Layer 3 Complete, a subscriber sends the current cell in the form of a Cell Identifier, which we store as a CGI, if necessary enriched with the local PLMN. Add enum with bitmask values to identify parts of a CGI, for the return value of gsm0808_cell_id_to_cgi(). Can't use enum CELL_IDENT for that, because it doesn't have a value for just a PLMN (and is not a bitmask). Change-Id: Ib9af67b100c4583342a2103669732dab2e577b04
* fsm: add osmo_fsm_inst_state_chg_keep_or_start_timer()Neels Hofmeyr2019-03-075-17/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | During FSM design for osmo-msc, I noticed that the current behavior that keep_timer=true doesn't guarantee a running timer can make FSM design a bit complex, especially when using osmo_tdef for timeout definitions. A desirable keep_timer=true behavior is one that keeps the previous timer running, but starts a timer if no timer is running yet. The simplest example is: a given state repeatedly transitions back to itself, but wants to set a timeout only on first entering, avoiding to restart the timeout on re-entering. Another example is a repeated transition between two or more states, where the first time we enter this group a timeout should start, but it should not restart from scratch on every transition. When using osmo_tdef timeout definitions for this, so far separate meaningless states have to be introduced that merely set a fixed timeout. To simplify, add osmo_fsm_inst_state_chg_keep_or_start_timer(), and use this in osmo_tdef_fsm_inst_state_chg() when both keep_timer == true *and* T != 0. In tdef_test.ok, the changes show that on first entering state L, the previous T=1 is now kept with a large remaining timeout. When entering state L from O, where no timer was running, this time L's T123 is started. Change-Id: Id647511a4b18e0c4de0e66fb1f35dc9adb9177db
* fix tdef_test.c: do call the function-to-test in all casesNeels Hofmeyr2019-03-063-19/+19
| | | | | | | | | | | | Always call osmo_tdef_fsm_inst_state_chg(), also when no timeout is defined. When there is no timeout defined for a state, tdef_test.c tries to be smart and print different output. In that mess, I missed the fact that osmo_tdef_fsm_inst_state_chg() isn't always called as it should. In the same mess, the resulting state was never printed until the preceding patch, which helped to hide this bug. Change-Id: I1d953d99854422bff8eb32f051e9c6147bc836b6
* tdef_test: tweak output to prepare for a fixNeels Hofmeyr2019-03-063-21/+24
| | | | | | | | | | | | | | - Always print the state after a state transition. This shows that actually state transitions are missing for states that have no timer defined. This is a bug in tdef_test.c, to be fixed subsequently. - Instead of total time passed since start, print the individual fake time intervals. Omit initial useless zero fake time advance. - Add two more state transitions, back out from and into a state that has no timeout set. Change-Id: Icb31af96d37741e256ff07868f3d4f5c48cdda74
* represent negative T-timers as Osmocom-specific X-timersNeels Hofmeyr2019-03-067-52/+111
| | | | | | | | | | | | | | | | | | | | fi->T values are int, i.e. can be negative. Do not log them as unsigned, but define a distinct timer class "Xnnnn" for negative T values: i.e. for T == -1, print "Timeout of X1" instead of "Timeout of T4294967295". The negative T timer number space is useful to distinguish freely invented timers from proper 3GPP defined T numbers. So far I was using numbers like T993210 or T9999 for invented T, but X1, X2 etc. is a better solution. This way we can make sure to not accidentally define an invented timer number that actually collides with a proper 3GPP specified timer number that the author was not aware of at the time of writing. Add OSMO_T_FMT and OSMO_T_FMT_ARGS() macros as standardized timer number print format. Use that in fsm.c, tdef_vty.c, and adjust vty tests accordingly. Mention the two timer classes in various API docs and VTY online-docs. Change-Id: I3a59457623da9309fbbda235fe18fadd1636bff6
* api doc: tweak gsm0808_cell_id_matches_list() docNeels Hofmeyr2019-03-051-1/+2
| | | | Change-Id: Ide94558d1c31356483252b83e04b061b4ee4d3bf
* coding: check gsm0503_rach_*() resultsMax2019-03-051-8/+10
| | | | | | | | Check return value of RACH encode/decode functions and fail test on unexpected results. Change-Id: I41bfa808e3c064a11152e7ce8ee77a01d38a0744 Related: OS#1854
* fix api doc typo for osmo_plmn_name2()Neels Hofmeyr2019-02-261-1/+1
| | | | Change-Id: Ic2652c7e4ffe1e707022168ac6c0da7c88ae7f45
* log: fsm: allow logging the timeout on state changeNeels Hofmeyr2019-02-264-12/+53
| | | | | | | | | | | | | | | | Add a flag that adds timeout info to osmo_fsm_inst state change logging. To not affect unit testing, make this an opt-in feature that is disabled by default -- mostly because osmo_fsm_inst_state_chg_keep_timer() will produce non-deterministic logging depending on timing (logs remaining time). Unit tests that don't verify log output and those that use fake time may also enable this feature. Do so in fsm_test.c. The idea is that in due course we will add osmo_fsm_log_timeouts(true) calls to all of our production applications' main() initialization. Change-Id: I089b81021a1a4ada1205261470da032b82d57872
* NS: Add support for GPRS NS IP Sub-Network-Service (SNS)Harald Welte2019-02-269-20/+1056
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The NS implementation part of the Gb implementation libosmogb so far implemented a rather classic dialect of Gb, with lots of heritage to FR (Frame Relay) transports. At least since Release 6 of the NS specification, there's an IP Sub-Network Service (SNS), which * permits for dynamic configuration of IP endpoints and their NS-VCs * abandons the concept of a NSVCI on IP transport * forbids the use of RESET/BLOCK/UNBLOCK procedures on IP transport This commit introduces BSS-side IP-SNS support to libosmogb in a minimally invasive way. It adds a corresponding SNS FSM to each NS instance, and implements the new SIZE/CONFIG/ADD/DELETE/CHANGE_WEIGHT procedures very closely aligned with the spec. In order to use the SNS flavor (rather than the classic one), a BSS implementation should use gprs_ns_nsip_connect_sns() instead of the existing gprs_ns_nsip_connect(). This implementation comes with a set of TTCN-3 tests in PCU_Tests_RAW_SNS.ttcn, see Change-ID I0fe3d4579960bab0494c294ec7ab8032feed4fb2 of osmo-ttcn3-hacks.git Closes: OS#3372 Closes: OS#3617 Change-Id: I84786c3b43a8ae34ef3b3ba84b33c90042d234ea
* NS: Factor out gprs_nsvc_start_test() and use itHarald Welte2019-02-263-15/+21
| | | | | | | | | | | | This function performs sending a NS-ALIVE PDU and starting Tns-Test, let's use it in all places where we used to do that. As part of this, also fix a bug where the sendto() return value (number of bytes sent) would actually propagate up all the way to gprs_ns_rx_reset() return value, which in turn affects the test results on stdout. Change-Id: I4d303117f77fabb74bbb91887b9914a81c2a084a
* gprs_ns: Add code for SNS-SIZE and SNS-CONFIG encodingHarald Welte2019-02-264-3/+207
| | | | | | | | | | | Modern NS specifications contain a SNS (Sub Network Service) for negotiating IP/port/weight parameters of NS-over-IP links dynamically. This patch adds message encoding routines for SNS-CONFIG, SNS-SIZE and their respective acknowledgements. Related: OS#3372 Change-Id: I5c47e1c3c10deb89a7470ee2c03adfc174accc93
* enlarge gsm0808 msgb headroomNeels Hofmeyr2019-02-261-2/+2
| | | | | | | | | | | | | | | | It should be large enough to prepend a struct osmo_scu_prim to pass down an SCCP stack (see libosmo-sccp). 264 should suffice, but pick the next larger power-of-two instead. In osmo-msc, I would like to prepend an osmo_prim to the msgb created by gsm0808 API, but turns out the headroom is too small: msgb(0x61700001b660): Not enough headroom msgb_push (126 < 264) Instead of always copying a msgb that has just that instant been created, it makes more sense to allocate sufficient headroom in the first place. Change-Id: I95729991eb49555f8bba60c5dc916131b03b6cf2
* LCLS: add string dump helpersMax2019-02-266-3/+54
| | | | | | | | | Add functions to dump LCLS (without GCR) and GCR. Dumping entire struct results in inconveniently long string hence the separate functions. Both use talloc functions so they expect caller to take care of providing proper allocation context and freeing memory. Change-Id: Ic3609224c8f3282d667e75f68bc20327e36eb9e6
* GPRS: Doxygen documentation for 'struct libgb_msgb_cb'Harald Welte2019-02-231-4/+4
| | | | Change-Id: I4144506feee74a8219bd3736087c30cc6323ec1d
* NS: Add missing NS Cause stringsHarald Welte2019-02-231-0/+7
| | | | | | | | When I added the definitions for the IP-SNS in commit f030b210e8c13314d361a6b721a0cbcc72935219 back in 2010, I forgot to update the string definitions in ns_cause_str[]. Let's fix that Change-Id: I419ccc482d99b01263a60aede83dacd2d9de56ab
* NS: Don't print information about FR/GRE if not enabled!Harald Welte2019-02-231-3/+4
| | | | Change-Id: I9209ee4ba5ebfc4f96b4c1d42840e1906455bae7
* Add multipatch capability to osmo-config-mergeMax2019-02-221-21/+45
| | | | | | | | | | That's pretty straightforward and convenient extention: handle all extra positional arguments as patch file names. This makes it similar to 'cp' and other coreutils basic tools. For example: osmo-config-merge base.cfg patch1.cfg patch2.cfg patch3.cfg will apply 3 patches to the base config file. Change-Id: I212cbdc3bf6f251c1a3175737ac74242fb004c6d
* select: Call log_reset_context() before calling file descriptor callbacksHarald Welte2019-02-211-0/+6
| | | | | | | | | | Make sure to clear any log context before processing the next incoming message as part of some file descriptor callback. This effectively prevents "context leaking" from processing of one message into processing of the next message as part of one iteration through the list of file descriptors here. Change-Id: I3644c7bc1a9cec5858eb0faf94efc8c3ba7f5d8d Closes: OS#3813
* gprs_ns: Add missing NSVCI IE to NS-BLOCK-ACK messageHarald Welte2019-02-191-1/+29
| | | | | | | | According to Section 9.2.4 of 3GPP TS 48.016, the NS-BLOCK-ACK PDU has a mandatory NSVCI IE which we so far were missing. Change-Id: Ie7205e99d57f1e42d941f1be2460d8c9f46aadfe Closes: OS#3808
* gprs_ns: Declare gprs_ns_tx_alive*() in header fileHarald Welte2019-02-191-0/+2
| | | | | | | The symbols for those functions were always exported, but we somehow didn't declare them in gprs_ns.h Change-Id: Ib073e9c93fcdf408b63000182e90aabce37f687e
* gprs_ns.c: cosmetic whitespace fixesHarald Welte2019-02-191-2/+2
| | | | Change-Id: Ic19f65bdc5527ad5a69d0a92320ce5f672bf4d2b
* gprs_ns: Use gprs_ns_tx_alive() instead of gprs_ns_tx_simple()Harald Welte2019-02-191-2/+2
| | | | | | If we use gprs_ns_tx_alive() we will get logging for free. Change-Id: I53d410d13540d389096c40425e1fa2eb7460b16b
* bssgp_tx_bvc_unblock(): Fix log messageHarald Welte2019-02-191-1/+1
| | | | | | | We're transmitting a BVC-UNBLOCK but the log states the opposite: BVC-BLOCK. Let's fix that. Change-Id: I70fa7336402d193513f89fcf3068b0b21925702d
* rsl: Support PDCH in rsl_chan_nr_strPau Espin Pedrol2019-02-181-0/+2
| | | | | | | | | | | | | | During log review lack of support for PDCH was spotted: scheduler.c:593 Configuring multiframe with PDCH trx=0 ts=4 rsl.c:1159 (bts=0,trx=0,ts=4,ss=0): chan_nr=UNKNOWN on TS4 type=0x00 mode=SIGNALLING rsl.c:741 (bts=0,trx=0,ts=4,pchan=TCH/F_TCH/H_PDCH as PDCH) (ss=0) PDTCH Tx CHAN ACT ACK Wireshark shows: 1100 0... = C-bits: PDCH (24) .... .100 = Time slot number (TN): 4 Change-Id: If6ed96c9eb0431eb24e2135634def61e0ea506ea
* gsm0808: Add unit tests for test_create_clear_command2()Harald Welte2019-02-182-0/+26
| | | | | Change-Id: Ie3f34b78edc91a013152742bebbd839586a787fe Related: OS#3805
* gsm0808: comment about difference of gsm0808_create_clear_command()Harald Welte2019-02-181-1/+4
| | | | | | | | This single function has a quite different behavior than the other gsm0808_ functions in terms of how the resulting msgb l3h pointers are set. Let's document that to avoid more confusion. Change-Id: I0367760a588fc968c5a2dea46001ef1ee7965c8c
* Fix BSSMAP length generated by gsm0808_create_clear_command2()Harald Welte2019-02-181-1/+7
| | | | | | | | | | In Change-Id Id8a75e1da2d5f520064666e4ee413d1c91da6ae3 we recently introduced adding the "CSFB INDICATOR" IE to the CLEAR COMMAND, but we did so with a wrong length value. Change-Id: I4d07d25fb03ca0f89fd7b94226c54309c77a010a Closes: OS#3805 Related: OS#2778
* add OSMO_STRBUF_PRINTF()Neels Hofmeyr2019-02-173-0/+188
| | | | | | | | | | We are using macros like this or different workarounds in libmsc. In the course of implementing inter-MSC handover, I am encountering yet another such situation of appending multiple strings to a limited char buffer. Standardize. Add a unit test to utils_test.c. Change-Id: I2497514e26c5e7a5d88985fc7e58343be1a027b2
* gsm_08_08.h: Add constants for Channel Type in signalling modeSylvain Munaut2019-02-171-0/+14
| | | | | | | | This is from TS 08.08 3.2.2.11 directly. The choices for Data mode and Speech mode were already present, but not for Signalling mode Change-Id: I9e24841ea877a9a78dc4d2bd14cbf60c4bea79a6 Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* fix osmo_gsm48_classmark* libosmogsm.map entriesNeels Hofmeyr2019-02-151-6/+6
| | | | | | | | When the initial patch was tweaked from osmo_classmark_* to osmo_gsm48_classmark_* naming, the libosmogsm.map entries were forgotten to be changed as well. Change-Id: I53a41b5e965a529d3c146ee85102f7f1725c6014
* get_value_string(): guard against NULLNeels Hofmeyr2019-02-151-0/+3
| | | | | | | | | | | | get_value_string() conveniently prints the value number to a static buffer if it is unknown in a value_string array. Do the same if the value_string array pointer itself is NULL. If a value string array is user supplied and might be NULL, one could add a separate NULL check around it; but by making get_value_string() itself guard against NULL, another static char buffer to print the value number is avoided. Change-Id: Ie640e9258a959da8f4f9089478de993509853997
* Enable remote SIM protocol log levelMax2019-02-142-1/+6
| | | | | | | It's defined in logging.h for quite some time but is not actually enabled alongside with other internal logging categories. Change-Id: I0e7a2add6293a072752900608c8ba34cc3850f31
* gsm/gsm0480: introduce gsm0480_create_release_complete()Vadim Yanitskiy2019-02-083-1/+26
| | | | | | | | | | | | In OsmoMSC, it's required to be able to specify a particular GSM 04.07 transaction ID for GSM 04.80 Release complete message instead of the hard-coded value, that is used gsm0480_create_ussd_release_complete(). Let's finally deprecate gsm0480_create_ussd_release_complete(), and introduce a new function without USSD prefix, as this message is also used in other "structured" supplementary services. Change-Id: Ie3ac85fcef90a5e532334ba3482804d5305c88d7
* protocol/gsm_04_14: Fix the OPEN LOOP message typeSylvain Munaut2019-02-071-1/+1
| | | | | Change-Id: Id4350dee4353ebf9de0450dd5dab6e4f2ee7c3a6 Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* platform independence fix: tdef range testsNeels Hofmeyr2019-02-068-133/+490
| | | | | | | | | | | | | Run INT_MAX and ULONG_MAX related tests only manually, remove from automatic testing. This will hopefully fix recent build failures on various platforms. Add a 64 bit output example for expected results when invoking `./tdef_test range'. This is not checked automatically and merely serves for manual reference. For vty tests, use 32bit max values instead of INT_MAX and ULONG_MAX. Change-Id: I6242243bde1d7ddebb858512a1f0b07f4ec3e5c2
* gsm0808: Add CSFB indication IE to BSSMAP CLEAR COMMANDPhilipp Maier2019-02-053-0/+18
| | | | | | | | | | | When a call that was established in a CSFB context ends the CLEAR COMMAND that is send from the BSC to the MSC should contain a CSFB indication IE, which consists of just the IE byte itsslef. This additional IE tells the BSC to include other CSFB related IEs into the RR Release message. Change-Id: Id8a75e1da2d5f520064666e4ee413d1c91da6ae3 Related: OS#3778
* bitvec: Add bitvec_tailroom_bits() functionHarald Welte2019-02-052-0/+25
| | | | | | | | | This is similar to msgb_tailroom(): It returns the amount of space left at the end of the bit vector (compared to the current cursor). The function returns the number of bits left in the bitvec. Change-Id: I8980a6b6d1973b67a2d9ad411c878d956fb428d1
* bitvec: Add bitvec_bytes_used() functionHarald Welte2019-02-053-0/+37
| | | | | | | This new bitvec API function returns the number of bytes used in a given bit-vector. Change-Id: Id4bd7f7543f5b0f4f6f876e283bd065039c37646
* gsm_08_08.h: Add IEI definitions from Release 15Harald Welte2019-02-051-0/+5
| | | | Change-Id: If3649606ba7c25121e30ed02939ca08c94665be5
* Extend gsm_04_08.h with CSFB related definitiosn form 44.018 Rel 15Harald Welte2019-02-051-0/+2
| | | | | | These are some IEI definitions that we'll need for CSFB Fast Return Change-Id: I0e101af316438b56d63d43fc2cb16d7caf563d07
* add osmo_tdef API, originally adopted from osmo-bsc T_defNeels Hofmeyr2019-02-0418-2/+2998
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move T_def from osmo-bsc to libosmocore as osmo_tdef. Adjust naming to be more consistent. Upgrade to first class API: - add timer grouping - add generic vty support - add mising API doc - add C test - add VTY transcript tests, also as examples for using the API From osmo_fsm_inst_state_chg() API doc, cross reference to osmo_tdef API. The root reason for moving to libosmocore is that I want to use the mgw_endpoint_fsm in osmo-msc for inter-MSC handover, and hence want to move the FSM to libosmo-mgcp-client. This FSM uses the T_def from osmo-bsc. Though the mgw_endpoint_fsm's use of T_def is minimal, I intend to use the osmo_tdef API in osmo-msc (and probably elsewhere) as well. libosmocore is the most sensible place for this. osmo_tdef provides: - a list of Tnnnn (GSM) timers with description, unit and default value. - vty UI to allow users to configure non-default timeouts. - API to tie T timers to osmo_fsm states and set them on state transitions. - a few standard units (minute, second, millisecond) as well as a custom unit (which relies on the timer's human readable description to indicate the meaning of the value). - conversion for standard units: for example, some GSM timers are defined in minutes, while our FSM definitions need timeouts in seconds. Conversion is for convenience only and can be easily avoided via the custom unit. By keeping separate osmo_tdef arrays, several groups of timers can be kept separately. The VTY tests in tests/tdef/ showcase different schemes: - tests/vty/tdef_vty_test_config_root.c: Keep several timer definitions in separately named groups: showcase the osmo_tdef_vty_groups*() API. Each timer group exists exactly once. - tests/vty/tdef_vty_test_config_subnode.c: Keep a single list of timers without separate grouping. Put this list on a specific subnode below the CONFIG_NODE. There could be several separate subnodes with timers like this, i.e. continuing from this example, sets timers could be separated by placing timers in specific config subnodes instead of using the global group name. - tests/vty/tdef_vty_test_dynamic.c: Dynamically allocate timer definitions per each new created object. Thus there can be an arbitrary number of independent timer definitions, one per allocated object. T_def was introduced during the recent osmo-bsc refactoring for inter-BSC handover, and has proven useful: - without osmo_tdef, each invocation of osmo_fsm_inst_state_chg() needs to be programmed with the right timeout value, for all code paths that invoke this state change. It is a likely source of errors to get one of them wrong. By defining a T timer exactly for an FSM state, the caller can merely invoke the state change and trust on the original state definition to apply the correct timeout. - it is helpful to have a standardized config file UI to provide user configurable timeouts, instead of inventing new VTY commands for each separate application of T timer numbers. Change-Id: Ibd6b1ed7f1bd6e1f2e0fde53352055a4468f23e5
* doxygen: allow manual 'make apidoc' even if --disable-doxygenNeels Hofmeyr2019-02-041-8/+17
| | | | | | | | | | | | Even if ./configure --disable-doxygen was passed and doxygen builds are by default skipped, provide a manual 'make apidoc' target that nevertheless generates the API doc on the premise that a 'doxygen' program is available. Especially since we do a two-pass doxygen build whenever any source file changes, my guess is --disable-doxygen could be a common choice. It is then cumbersome to have to ./configure just to get one doxygen build started. Change-Id: If8d8dfb8365c8f28612b8ce2b8ddf88f74df9a90
* doxygen: add source files as dependenciesNeels Hofmeyr2019-02-041-7/+25
| | | | | | | | | | | | | | | | | So far, when modifying a source file, the doxygen docs were not regenerated automatically. It required a manual 'rm -rf docs/core' or similar. Make it rebuild automatically: Add each library's source files to the list of dependencies for the first-pass doxygen build. Attention, since all libraries depend on the .map files of each other library, and each library depends on its own source files, that means that a single touch on one .c file anywhere will result in rebuilding the entire doxygen docs. It is correct to do so, since any file may introduce \ref targets used anywhere else. If you don't want that, --disable-doxygen. Change-Id: I15ea96be6e7abe91264b91f0b06963a0f2d63b0b
* doxygen: enable cross referencing everywhereNeels Hofmeyr2019-02-048-28/+130
| | | | | | | | | | | | | | | | | | | | | | | | doxygen \ref cross-references to groups or files from other libraries only work when the .map file was present when the HTML was generated, and when that .map file was listed in TAGFILES in the Doxyfile. - Makefile.am: introduce a two-pass build for doxygen API docs. - First build pass makes sure the .tag files are present. - Second build pass picks up all the references, hence generates hyperlinks properly. - Add all libraries to TAGFILES of all other libraries, so we can from now on freely criss-cross reference from everywhere to everywhere. - Add all libraries' tag files as dependencies for all others. Example: in upcoming tdef.h, I would like to cross reference to tdef_vty.h, and vice versa, even though they are in libosmocore and libosmovty, respectively. This is now possible. We may still need to fix some problems with naming collisions, see for example stats.h, which exists twice with identical doxygen handle (different source dirs seems to not suffice for doxygen). Change-Id: Ib03d0b70d536c8f1386def666c89106a840f7363
* vty api: add vty_out_va()Neels Hofmeyr2019-02-042-12/+20
| | | | | | | | | Provide a va_list type vty_out() variant, to be able to pass on variable arguments from other function signatures to vty_out(). This will be used by Ibd6b1ed7f1bd6e1f2e0fde53352055a4468f23e5 for osmo_tdef. Change-Id: Ie6e6f11a6b794f3cb686350c1ed678e4d5bbbb75
* vty telnet: consistently never change nodes upon CTRL-CNeels Hofmeyr2019-02-041-18/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove any special node exiting from the VTY CTRL-C handling. From a curious VTY transcript test glitch, I noticed weird behavior by the VTY telnet shell: usually, when the user hits CTRL-C, that means to cancel the current command line and present a fresh, clean prompt. However, only on the CONFIG_NODE and CFG_LOG_NODE, a CTRL-C also exits the current node and moves up by one level. This behavior is unexplainable and makes zero sense. No other nodes exit on CTRL-C: - on the ENABLE node, a CTRL-C stays on the ENABLE_NODE and doesn't exit to the VIEW_NODE. - any sub-nodes of the CONFIG_NODE stay unchanged, e.g. 'network' or 'bts' / 'trx', etc. There is no apparent special meaning of CTRL-C on CONFIG_NODE nor CFG_LOG_NODE to justify this odd choice. Particularly, the vty transcript tests using osmo_verify_transcript_vty.py rely on sending CTRL-C to clear the command prompt, so that we can properly test sending