osmocom-net-gprs January 2014

osmocom-net-gprs@lists.osmocom.org

12 participants
6 discussions

State of sysmocom/master and upcoming work
by Holger Hans Peter Freyther 16 Jan '14

16 Jan '14

Hi, Daniel and me spent another day in the sysmocom office to go through the PCU code. We finished clean-ups, made some simple manual tests and looked at the traces. We will work on the following items during the next weeks: * For DL handling and multi-slot allocation more than one slot will only be allocated _after_ the TBF is re-used. E.g. for a simple download this might mean a single slot is used for the entire download. Daniel made a prototype to send a packet downlink assignment directly _after_ the assignment through the CCCH has completed. We manage to run into a use after free in the TBF code but will work on it. The issue is that the start of a TBF will take a bit longer. We might want to add some heuristic to decide when or when not to do it. * Re-sending and window stalls. When the entire window has been sent once, resending will start but when the ACK/NACK is arrived the resending will conntinue. As it is more likely that frames have arrived we should stop the resending and increase the window. This will increase the throughput. cheers holger -- - Holger Freyther <hfreyther(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Schivelbeiner Str. 5 * 10439 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Directors: Holger Freyther, Harald Welte

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[PATCH 1/1] Set csnStream direction *after* csnStreamInit
by Daniel Willmann 16 Jan '14

16 Jan '14

Fixes a bug introduced in commit 402cdc. That commit sets direction to zero so setting it to 1 should be done after the call to csnStreamInit(). This issue was discovered by the rlcmac test. --- src/csn1.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/csn1.cpp b/src/csn1.cpp index 7f64823..258f7c9 100644 --- a/src/csn1.cpp +++ b/src/csn1.cpp @@ -544,11 +544,11 @@ csnStreamDecoder(csnStream_t* ar, const CSN_DESCR* pDescr, bitvec *vector, unsig guint8 length = bitvec_read_field(vector, readIndex, length_len); LOGPC(DCSN1, LOGL_NOTICE, "%s length = %d | ", pDescr->sz , (int)length); - arT.direction = 1; bit_offset += length_len; remaining_bits_len -= length_len; csnStreamInit(&arT, bit_offset, length); + arT.direction = 1; Status = serialize(&arT, vector, readIndex, pvDATA(data, pDescr->offset)); if (Status >= 0) -- 1.8.4.2

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Multislot allocation failures and defects
by Holger Hans Peter Freyther 16 Jan '14

16 Jan '14

Dear Andreas, I went through the multislot allocation algorithm and cleaned and structured the code in testable parts that take over parts of the allocation and I have added a unit test for some of the allocation cases (UL first, then DL.. e.g. due a RACH burst and then DL single, UL and DL update). Today morning I added a testcase that tests all PDCH combinations and all MS Classes and verifies that an allocation takes place and that the DL and UL first_common_ts do match. For (xxOxOOxO) and MS_Class=5 this assert is wrong. The alloc/AllocTest of the sysmocom/allocation-cleanups branch should show you this condition. While reading the code I noticed the following things. Could you please explain why these are problems or no problems. * select_first_ts (it exists after the refactoring). It initializes i and compares it but it will never increment it. This means that the code can look at PDCHs _outside_ of the tx_range. * first_common_ts handling. When assigning the DL tbf we pick a first_common_ts but when the actual UL assignment happens there might not be a free USF on the Uplink and at that point the phone might not listen on the TS we think. * Sum for Rx+Tx is not used. I see that in update_rx_win_max you modify the window to make some room. * select_ul_slots. "i" is not incremented in all cases which could potentially lead to using slots outside of the tx_range. For the MS Type == 1 handling you could introduce a different variable that counts how many slots were used? it would be nice if we could fix that during the 30C3. holger -- - Holger Freyther <hfreyther(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Schivelbeiner Str. 5 * 10439 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Directors: Holger Freyther, Harald Welte

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Coverity issues in gsm_rlcmac.cpp
by Holger Hans Peter Freyther 16 Jan '14

16 Jan '14

Dear Ivan, could you please have a look at the coverity issues in the gsm_rlcmac.cpp routines? Uninitialized scalar variable: gsm_rlcmac.cpp:5321 ar.direction not initialized gsm_rlcmac.cpp:5039 ar.direction not initialized gsm_rlcmac.cpp:5155 ar.direction not initialized gsm_rlcmac.cpp:4872 ar.direction not initialized Just initialize it in csnStreamInit? Out-of-bounds read: gsm_rlcmac.cpp:5502 " Overrunning array "data->RLC_DATA" of 20 bytes at byte offset 22 using index "i" (which evaluates to 22)." gsm_rlcmac.cpp:5440 " Overrunning array "data->RLC_DATA" of 20 bytes at byte offset 22 using index "i" (which evaluates to 22)." Maybe just add an assert that dataNumOctets <= 20? -- - Holger Freyther <hfreyther(a)sysmocom.de> http://www.sysmocom.de/ ======================================================================= * sysmocom - systems for mobile communications GmbH * Schivelbeiner Str. 5 * 10439 Berlin, Germany * Sitz / Registered office: Berlin, HRB 134158 B * Geschaeftsfuehrer / Managing Directors: Holger Freyther, Harald Welte

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[PATCH] alloc_algorithm_b: Remove obsolete 'i' incrementation from for-loop
by Andreas Eversberg 15 Jan '14

15 Jan '14

--- src/gprs_rlcmac_ts_alloc.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/gprs_rlcmac_ts_alloc.cpp b/src/gprs_rlcmac_ts_alloc.cpp index 58dd2e9..366732c 100644 --- a/src/gprs_rlcmac_ts_alloc.cpp +++ b/src/gprs_rlcmac_ts_alloc.cpp @@ -459,7 +459,7 @@ inc_window: "1 slot assigned\n"); break; } - if (++i == ms_max_txslots) { + if (i+1 == ms_max_txslots) { LOGP(DRLCMAC, LOGL_DEBUG, "- Done, because " "slots / window reached maximum " "allowed Tx size\n"); -- 1.8.1.5 --------------010607040705070003040009--

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[RFC] [ADMIN] Making lists subscriber-only?
by Harald Welte 15 Jan '14

15 Jan '14

Dear all, so far the osmocom.org mailing lists have always been in a 'non-members are manually moderated' mode. This has created a lot of work for manual list moderation, where a lot of the messages caught are simply spam, and only the occasional valid message is being received. I'd like to thank the list moderators for taking care of this. However, in more recent discussions, we were considering to move the lists to a completely closed mode, i.e. postings would automatically be rejected from non-members. The automatic response would contain a description of how to subscribe in 'nomail' mode, i.e. to subscribe in a way to be able to post to the list, while still not receiving any incoming traffic. The latter should be fine for occasional posters who don't want the bulk e-mail that goes with a full/regular subscription. Please provide feedback in case you disagree with that change. Unless there is major opposition, we will likely transition to the 'closed' mode within one month. Thanks, 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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osmocom-net-gprs January 2014