osmocom-net-gprs October 2013

osmocom-net-gprs@lists.osmocom.org

4 participants
10 discussions

Dropping LLC frames due the TBF destruction
by Holger Hans Peter Freyther 07 Nov '13

07 Nov '13

Hi, my clean-ups are not done but there is a basic structure now that can be refined. I started to add statistics to the BTS (and then will add statistics per tbf but they are short lived so one would need to be quick to see them). E.g. in tbf_free we are freeing still pending llc_frames and I assume that these are related to the "Killing pending DL TBF" and others. I am wondering why: * there is no indication to the SGSN for dropped frames/octets? * can't the DL-TBF be re-associated/updated after the assignment is done again? 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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Losing ACKs due TLLI changes?
by Holger Hans Peter Freyther 05 Nov '13

05 Nov '13

Hi, I got this log from the pcu while using my E71 (the only sub in this network). <0007> gprs_rlcmac_meas.cpp:103 UL RSSI of TLLI=0x88661bc6: -67 dBm <0002> bts.cpp:945 Got ACK, but UL TBF is gone TLLI=0xe512eba3 <0007> gprs_rlcmac_meas.cpp:158 DL packet loss of IMSI=274080000004765 / TLLI=0xe512eba3: 0% <0002> tbf.cpp:668 TBF TFI=0 TLLI=0x88661bc6 T3169 timeout during transsmission <0002> tbf.cpp:690 - Assignment was on PACCH <0002> tbf.cpp:694 - No uplink data received yet So there is an ACK for TLLI=0xe512eba3 but at the same time the tlli 0x88661bc6 is timing out. PCU->SGSN TLLI=0x88661bc6 Attach Request SGSN->PCU TLLI=0x88661bc6 Attach Accept (new P-TMSI) PCU->SGSN TLLI=0xe512eba3 Attach Complete (new TLLI) (6s later) Now the question is how the PCU should behave. I think the MS is allowed to change the TLLI (after a P-TMSI assignment) after the contention resolution is completed. From my reading there is no content resolution on the UL. My E71 appears to run into a timeout and then issue a RACH request to send the Attach Complete. I think I have seen other equipment failing to transmit the Attach Complete at all. I think for the SGSN -> PCU side we should generally look things up by IMSI (there is already a warning in the code), for the MS->PCU side. I think we should store the old and new TLLI (and then put new_tlli into tlli once the new one is being used). comments? 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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Fwd: Losing ACKs due TLLI changes?
by Vladimir Rolbin 31 Oct '13

31 Oct '13

Hi, I don't see any print connected to the Uplink TBF request for "Attach accept" (by MS). At this moment the TLLI has been already updated but UL TBF still does not exist (what bts->tbf_by_tlli(m_tlli, GPRS_RLCMAC_UL_TBF) returns?). Corresponding to TS 04.60, 11.2.29 Packet Uplink Assignment possibly may use DL TFI to address the MS in place of TLLI (we still don't know if it's accepted or not by MS). Also the uplink FN may be used to find corresponding UL TBF context (according to Packet Uplink Assignment RRBP field) for UL Packet Control Ack which contains relevant TLLI. So is it really necessary to link UL and DL TBFs in the case? ... Regards, Vladimir Rolbin On Wed, Oct 30, 2013 at 1:17 PM, Holger Hans Peter Freyther < hfreyther(a)sysmocom.de> wrote: > On Sun, Oct 27, 2013 at 01:33:13PM +0100, Holger Hans Peter Freyther wrote: > > Hi, > > > > <0007> gprs_rlcmac_meas.cpp:103 UL RSSI of TLLI=0x88661bc6: -67 dBm > > <0002> bts.cpp:945 Got ACK, but UL TBF is gone TLLI=0xe512eba3 > > <0007> gprs_rlcmac_meas.cpp:158 DL packet loss of IMSI=274080000004765 / > TLLI=0xe512eba3: 0% > > <0002> tbf.cpp:668 TBF TFI=0 TLLI=0x88661bc6 T3169 timeout during > transsmission > > <0002> tbf.cpp:690 - Assignment was on PACCH > > <0002> tbf.cpp:694 - No uplink data received yet > > this is from a routing area update (with some printf debugging): > > > TBF(TFI=0 TLLI=0xb68154e6 DIR=DL) TLLLI changed...... > 0xb68154e6->0xc782d1de > <0002> tbf.cpp:1626 TBF(TFI=0 TLLI=0xb68154e6 DIR=DL) changing tlli to > TLLI=0xc782d1de > <0002> bts.cpp:941 Got ACK, but UL TBF is gone TLLI=0xc782d1de > <0007> gprs_rlcmac_meas.cpp:158 DL packet loss of IMSI=274080000004765 / > TLLI=0xc782d1de: 0% > <0002> tbf.cpp:664 TBF(TFI=0 TLLI=0xb68154e6 DIR=UL) T3169 timeout during > transsmission > <0002> tbf.cpp:686 - Assignment was on PACCH > <0002> tbf.cpp:690 - No uplink data received yet > > So the DL TLLI has been changed and then we get an ACK for a UL tbf > with the new TLLI and can't find it. And run into a timeout. > > > I have applied this change: > > diff --git a/src/tbf.cpp b/src/tbf.cpp > index fac5aaf..19bb83c 100644 > --- a/src/tbf.cpp > +++ b/src/tbf.cpp > @@ -1618,6 +1618,17 @@ void gprs_rlcmac_tbf::update_tlli(uint32_t tlli) > if (tlli == m_tlli) > return; > > + printf("%s TLLLI changed...... 0x%08x->0x%08x\n", > + tbf_name(this), m_tlli, tlli); > + > + if (direction == GPRS_RLCMAC_DL_TBF) { > + gprs_rlcmac_tbf *ul_tbf; > + ul_tbf = bts->tbf_by_tlli(m_tlli, GPRS_RLCMAC_UL_TBF); > + > + if (ul_tbf) > + ul_tbf->m_tlli = tlli; > + } > + > #warning "TODO.. find the DL/UL opposite and update the TLLI too" > LOGP(DRLCMAC, LOGL_NOTICE, "%s changing tlli to TLLI=0x%08x\n", > tbf_name(this), tlli); > > > and now the "Attach Complete" comes immediately after the Attach Accept. > I will push something like this but we really need a better way to link > the DL/UL TBFs together. > > > 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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Status on re-factorings
by Holger Hans Peter Freyther 28 Oct '13

28 Oct '13

Hi all, I have continued with my refactorings and mostly done: * Remove global state (e.g. the global lists for ta, sba, tbf, bts * Add back-pointers to tbf, trx, pdch which will allow to kill methods that take trx, ts as parameters. * Started to use C++ classes and functions. * Stop poking of internals from other classes areas (gprs_rlcmac_data is still in front of me and the most hairy part). I will probably need to spend another 40h on this code to finally have structure in it. Once this is done I will add counters and rate counters, improve the VTY inspection... and then I can search for the actual defects we are experiencing. While doing the refactorings I noticed that both pcu_l1_if.cpp and sysmo_sock.cpp have different ways to reset the BTS/PCU state. Both of them have different issues and are both incomplete. It is the perfect example where structure would have saved timed and made the code more reliable at the same time. I am going to work on gprs_rlcmac_data.cpp and while my refactorings so far where low risk.. the risk will increase when touching and structuring the above, e.g. it is hard to judge if the difference in the code-clones is on purpose or actually a bug. There will be only one way to find it out though. I am afraid that I have 52 commits compares to master and I am only half way done. Review and changing directions will be quite difficult at this point in time. 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 1/8] tbf: Move the struct to the tbf.h header file
by Holger Hans Peter Freyther 19 Oct '13

19 Oct '13

From: Holger Hans Peter Freyther <holger(a)moiji-mobile.com> This is the begin of a long march of turning tbf into a C++ class and properly hiding the secrets inside this implementation instead of having it spread across various different files. --- src/gprs_rlcmac.cpp | 1 + src/gprs_rlcmac.h | 97 -------------------------------------------- src/gprs_rlcmac_meas.cpp | 1 + src/gprs_rlcmac_sched.cpp | 1 + src/pcu_l1_if.cpp | 1 + src/tbf.h | 100 +++++++++++++++++++++++++++++++++++++++++++++- 6 files changed, 103 insertions(+), 98 deletions(-) diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp index 6546f8a..3dab44f 100644 --- a/src/gprs_rlcmac.cpp +++ b/src/gprs_rlcmac.cpp @@ -22,6 +22,7 @@ #include <gprs_bssgp_pcu.h> #include <pcu_l1_if.h> #include <gprs_rlcmac.h> +#include <tbf.h> /* 3GPP TS 05.02 Annex B.1 */ diff --git a/src/gprs_rlcmac.h b/src/gprs_rlcmac.h index 8de7417..6fdf600 100644 --- a/src/gprs_rlcmac.h +++ b/src/gprs_rlcmac.h @@ -155,103 +155,6 @@ enum gprs_rlcmac_tbf_direction { #define GPRS_RLCMAC_FLAG_TO_DL_ASS 7 #define GPRS_RLCMAC_FLAG_TO_MASK 0xf0 /* timeout bits */ -struct gprs_rlcmac_tbf { - struct llist_head list; - enum gprs_rlcmac_tbf_state state; - uint32_t state_flags; - enum gprs_rlcmac_tbf_direction direction; - uint8_t tfi; - uint32_t tlli; - uint8_t tlli_valid; - uint8_t trx; - uint16_t arfcn; - uint8_t tsc; - uint8_t first_ts; /* first TS used by TBF */ - uint8_t first_common_ts; /* first TS that the phone can send and - reveive simultaniously */ - uint8_t control_ts; /* timeslot control messages and polling */ - uint8_t ms_class; - struct gprs_rlcmac_pdch *pdch[8]; /* list of PDCHs allocated to TBF */ - uint16_t ta; - uint8_t llc_frame[LLC_MAX_LEN]; /* current DL or UL frame */ - uint16_t llc_index; /* current write/read position of frame */ - uint16_t llc_length; /* len of current DL LLC_frame, 0 == no frame */ - struct llist_head llc_queue; /* queued LLC DL data */ - - enum gprs_rlcmac_tbf_dl_ass_state dl_ass_state; - enum gprs_rlcmac_tbf_ul_ass_state ul_ass_state; - enum gprs_rlcmac_tbf_ul_ack_state ul_ack_state; - - enum gprs_rlcmac_tbf_poll_state poll_state; - uint32_t poll_fn; /* frame number to poll */ - - uint16_t ws; /* window size */ - uint16_t sns; /* sequence number space */ - - /* Please note that all variables here will be reset when changing - * from WAIT RELEASE back to FLOW state (re-use of TBF). - * All states that need reset must be in this struct, so this is why - * variables are in both (dl and ul) structs and not outside union. - */ - union { - struct { - uint16_t bsn; /* block sequence number */ - uint16_t v_s; /* send state */ - uint16_t v_a; /* ack state */ - char v_b[RLC_MAX_SNS/2]; /* acknowledge state array */ - int32_t tx_counter; /* count all transmitted blocks */ - char imsi[16]; /* store IMSI for PCH retransmission */ - uint8_t wait_confirm; /* wait for CCCH IMM.ASS cnf */ - } dl; - struct { - uint16_t bsn; /* block sequence number */ - uint16_t v_r; /* receive state */ - uint16_t v_q; /* receive window state */ - char v_n[RLC_MAX_SNS/2]; /* receive state array */ - int32_t rx_counter; /* count all received blocks */ - uint8_t n3103; /* N3103 counter */ - uint8_t usf[8]; /* list USFs per PDCH (timeslot) */ - uint8_t contention_resolution_done; /* set after done */ - uint8_t final_ack_sent; /* set if we sent final ack */ - } ul; - } dir; - uint8_t rlc_block[RLC_MAX_SNS/2][RLC_MAX_LEN]; /* block history */ - uint8_t rlc_block_len[RLC_MAX_SNS/2]; /* block len of history */ - - uint8_t n3105; /* N3105 counter */ - - struct osmo_timer_list timer; - unsigned int T; /* Txxxx number */ - unsigned int num_T_exp; /* number of consecutive T expirations */ - - struct osmo_gsm_timer_list gsm_timer; - unsigned int fT; /* fTxxxx number */ - unsigned int num_fT_exp; /* number of consecutive fT expirations */ - - struct { - char imsi[16]; - - struct timeval dl_bw_tv; /* timestamp for dl bw calculation */ - uint32_t dl_bw_octets; /* number of octets since bw_tv */ - - struct timeval rssi_tv; /* timestamp for rssi calculation */ - int32_t rssi_sum; /* sum of rssi values */ - int rssi_num; /* number of rssi values added since rssi_tv */ - - struct timeval dl_loss_tv; /* timestamp for loss calculation */ - uint16_t dl_loss_lost; /* sum of lost packets */ - uint16_t dl_loss_received; /* sum of received packets */ - - } meas; - - uint8_t cs; /* current coding scheme */ - -#ifdef DEBUG_DIAGRAM - int diag; /* number where TBF is presented in diagram */ - int diag_new; /* used to format output of new TBF */ -#endif -}; - extern struct llist_head gprs_rlcmac_ul_tbfs; /* list of uplink TBFs */ extern struct llist_head gprs_rlcmac_dl_tbfs; /* list of downlink TBFs */ extern struct llist_head gprs_rlcmac_sbas; /* list of single block allocs */ diff --git a/src/gprs_rlcmac_meas.cpp b/src/gprs_rlcmac_meas.cpp index 75da835..3229795 100644 --- a/src/gprs_rlcmac_meas.cpp +++ b/src/gprs_rlcmac_meas.cpp @@ -20,6 +20,7 @@ #include <gprs_rlcmac.h> #include <gprs_debug.h> #include <pcu_l1_if.h> +#include <tbf.h> #include <string.h> #include <errno.h> diff --git a/src/gprs_rlcmac_sched.cpp b/src/gprs_rlcmac_sched.cpp index 6290c5d..f3edaac 100644 --- a/src/gprs_rlcmac_sched.cpp +++ b/src/gprs_rlcmac_sched.cpp @@ -20,6 +20,7 @@ #include <gprs_bssgp_pcu.h> #include <gprs_rlcmac.h> #include <pcu_l1_if.h> +#include <tbf.h> uint32_t sched_poll(uint8_t trx, uint8_t ts, uint32_t fn, uint8_t block_nr, struct gprs_rlcmac_tbf **poll_tbf, diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp index 218dc23..47bf740 100644 --- a/src/pcu_l1_if.cpp +++ b/src/pcu_l1_if.cpp @@ -37,6 +37,7 @@ extern "C" { #include <gprs_debug.h> #include <gprs_bssgp_pcu.h> #include <pcuif_proto.h> +#include <tbf.h> // FIXME: move this, when changed from c++ to c. extern "C" { diff --git a/src/tbf.h b/src/tbf.h index 330eac1..a6dfced 100644 --- a/src/tbf.h +++ b/src/tbf.h @@ -18,9 +18,107 @@ #pragma once +#include "gprs_rlcmac.h" + #include <stdint.h> -struct gprs_rlcmac_bts; +struct gprs_rlcmac_tbf { + struct llist_head list; + enum gprs_rlcmac_tbf_state state; + uint32_t state_flags; + enum gprs_rlcmac_tbf_direction direction; + uint8_t tfi; + uint32_t tlli; + uint8_t tlli_valid; + uint8_t trx; + uint16_t arfcn; + uint8_t tsc; + uint8_t first_ts; /* first TS used by TBF */ + uint8_t first_common_ts; /* first TS that the phone can send and + reveive simultaniously */ + uint8_t control_ts; /* timeslot control messages and polling */ + uint8_t ms_class; + struct gprs_rlcmac_pdch *pdch[8]; /* list of PDCHs allocated to TBF */ + uint16_t ta; + uint8_t llc_frame[LLC_MAX_LEN]; /* current DL or UL frame */ + uint16_t llc_index; /* current write/read position of frame */ + uint16_t llc_length; /* len of current DL LLC_frame, 0 == no frame */ + struct llist_head llc_queue; /* queued LLC DL data */ + + enum gprs_rlcmac_tbf_dl_ass_state dl_ass_state; + enum gprs_rlcmac_tbf_ul_ass_state ul_ass_state; + enum gprs_rlcmac_tbf_ul_ack_state ul_ack_state; + + enum gprs_rlcmac_tbf_poll_state poll_state; + uint32_t poll_fn; /* frame number to poll */ + + uint16_t ws; /* window size */ + uint16_t sns; /* sequence number space */ + + /* Please note that all variables here will be reset when changing + * from WAIT RELEASE back to FLOW state (re-use of TBF). + * All states that need reset must be in this struct, so this is why + * variables are in both (dl and ul) structs and not outside union. + */ + union { + struct { + uint16_t bsn; /* block sequence number */ + uint16_t v_s; /* send state */ + uint16_t v_a; /* ack state */ + char v_b[RLC_MAX_SNS/2]; /* acknowledge state array */ + int32_t tx_counter; /* count all transmitted blocks */ + char imsi[16]; /* store IMSI for PCH retransmission */ + uint8_t wait_confirm; /* wait for CCCH IMM.ASS cnf */ + } dl; + struct { + uint16_t bsn; /* block sequence number */ + uint16_t v_r; /* receive state */ + uint16_t v_q; /* receive window state */ + char v_n[RLC_MAX_SNS/2]; /* receive state array */ + int32_t rx_counter; /* count all received blocks */ + uint8_t n3103; /* N3103 counter */ + uint8_t usf[8]; /* list USFs per PDCH (timeslot) */ + uint8_t contention_resolution_done; /* set after done */ + uint8_t final_ack_sent; /* set if we sent final ack */ + } ul; + } dir; + uint8_t rlc_block[RLC_MAX_SNS/2][RLC_MAX_LEN]; /* block history */ + uint8_t rlc_block_len[RLC_MAX_SNS/2]; /* block len of history */ + + uint8_t n3105; /* N3105 counter */ + + struct osmo_timer_list timer; + unsigned int T; /* Txxxx number */ + unsigned int num_T_exp; /* number of consecutive T expirations */ + + struct osmo_gsm_timer_list gsm_timer; + unsigned int fT; /* fTxxxx number */ + unsigned int num_fT_exp; /* number of consecutive fT expirations */ + + struct { + char imsi[16]; + + struct timeval dl_bw_tv; /* timestamp for dl bw calculation */ + uint32_t dl_bw_octets; /* number of octets since bw_tv */ + + struct timeval rssi_tv; /* timestamp for rssi calculation */ + int32_t rssi_sum; /* sum of rssi values */ + int rssi_num; /* number of rssi values added since rssi_tv */ + + struct timeval dl_loss_tv; /* timestamp for loss calculation */ + uint16_t dl_loss_lost; /* sum of lost packets */ + uint16_t dl_loss_received; /* sum of received packets */ + + } meas; + + uint8_t cs; /* current coding scheme */ + +#ifdef DEBUG_DIAGRAM + int diag; /* number where TBF is presented in diagram */ + int diag_new; /* used to format output of new TBF */ +#endif +}; + /* dispatch Unitdata.DL messages */ int tbf_handle(struct gprs_rlcmac_bts *bts, -- 1.8.4.rc3

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Fairness of sched_poll
by Holger Hans Peter Freyther 17 Oct '13

17 Oct '13

Good Morning, sched_poll is doing: llist_for_each_entry(tbf, &gprs_rlcmac_ul_tbfs, list) { /* this trx, this ts */ if (tbf->trx_no != trx || tbf->control_ts != ts) continue; /* polling for next uplink block */ if (tbf->poll_state == GPRS_RLCMAC_POLL_SCHED && tbf->poll_fn == poll_fn) *poll_tbf = tbf; if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_SEND_ACK) *ul_ack_tbf = tbf; if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS) *dl_ass_tbf = tbf; if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS) *ul_ass_tbf = tbf; } llist_for_each_entry(tbf, &gprs_rlcmac_dl_tbfs, list) { /* this trx, this ts */ if (tbf->trx_no != trx || tbf->control_ts != ts) continue; /* polling for next uplink block */ if (tbf->poll_state == GPRS_RLCMAC_POLL_SCHED && tbf->poll_fn == poll_fn) *poll_tbf = tbf; if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS) *dl_ass_tbf = tbf; if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS) *ul_ass_tbf = tbf; } New tbf's will be added to the front (llist_add). Is it on purpose that the dl_tbfs are preferred over ul_tbfs and that the last of each tbf's will be found? What is the reasoning for this? What will collect/catch poll_fn's that are in the past? 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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TBF differences for Uplink and Downlink
by Holger Hans Peter Freyther 17 Oct '13

17 Oct '13

Hi, in my refactorings (creating a TBF class and moving code that modifes the internals into the TBF) I am trying to make gprs_rlcmac_ul_tbfs and gprs_rlcmac_dl_tbfs private and I notice code like: if (dir == GPRS_RLCMAC_UL_TBF) { llist_for_each_entry(tbf, &gprs_rlcmac_ul_tbfs, list) { if (tbf->state_is_not(GPRS_RLCMAC_RELEASING) && tbf->tlli == tlli && tbf->tlli_valid) return tbf; } } else { llist_for_each_entry(tbf, &gprs_rlcmac_dl_tbfs, list) { if (tbf->state_is_not(GPRS_RLCMAC_RELEASING) && tbf->tlli == tlli) return tbf; } } llist_for_each_entry(tbf, &gprs_rlcmac_ul_tbfs, list) { if (tbf->state_is_not(GPRS_RLCMAC_RELEASING) && tbf->poll_state == GPRS_RLCMAC_POLL_SCHED && tbf->poll_fn == fn && tbf->trx_no == trx && tbf->control_ts == ts) return tbf; } llist_for_each_entry(tbf, &gprs_rlcmac_dl_tbfs, list) { if (tbf->state_is_not(GPRS_RLCMAC_RELEASING) && tbf->poll_state == GPRS_RLCMAC_POLL_SCHED && tbf->poll_fn == fn && tbf->trx_no == trx && tbf->control_ts == ts) return tbf; } In the first code. Why is tlli_valid only checked for the UL TBF and not the downlink one? 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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Question regarding TS allocation algorithm(s)
by Holger Hans Peter Freyther 17 Oct '13

17 Oct '13

Hi, after the report about the missing usf assignment I started to refactor the allocation algorithms (remove code duplication, apply information hiding, directly access things). Looking at the code it appears that algorithm A and B will always select the first (in case of A) or the first and following (in case of B) enabled PDCH. I have the suspicion that in case of algorithm A only the first PDCH will be used to assign to phones? And in case of algorithm B it is likely that the assignments are not spread equally across the available timeslots? can someone confirm/deny? 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 1/8] tbf: Begin to add some structure to the tbf code
by Holger Freyther 16 Oct '13

16 Oct '13

From: Holger Hans Peter Freyther <holger(a)moiji-mobile.com> The TBF should use the IMSI to identify a block flow but all handling is spread across the entire code. Start to clean this up by moving relevant code into the tbf file. Afterwards one can clean up and add more internal structure. --- src/Makefile.am | 6 +- src/gprs_bssgp_pcu.cpp | 121 +------------------------------------ src/tbf.cpp | 160 +++++++++++++++++++++++++++++++++++++++++++++++++ src/tbf.h | 27 +++++++++ 4 files changed, 194 insertions(+), 120 deletions(-) create mode 100644 src/tbf.cpp create mode 100644 src/tbf.h diff --git a/src/Makefile.am b/src/Makefile.am index 38a4b3c..6646f53 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -40,7 +40,8 @@ libgprs_la_SOURCES = \ gsm_timer.cpp \ bitvector.cpp \ pcu_l1_if.cpp \ - pcu_vty.c + pcu_vty.c \ + tbf.cpp if ENABLE_SYSMOBTS libgprs_la_SOURCES += \ @@ -72,7 +73,8 @@ noinst_HEADERS = \ bitvector.h \ pcu_vty.h \ sysmo_l1_if.h \ - femtobts.h + femtobts.h \ + tbf.h osmo_pcu_SOURCES = pcu_main.cpp diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp index 4833af8..3432bca 100644 --- a/src/gprs_bssgp_pcu.cpp +++ b/src/gprs_bssgp_pcu.cpp @@ -21,6 +21,7 @@ #include <gprs_rlcmac.h> #include <gprs_bssgp_pcu.h> #include <pcu_l1_if.h> +#include <tbf.h> static struct gprs_bssgp_pcu the_pcu = { 0, }; @@ -103,12 +104,9 @@ static int gprs_bssgp_pcu_rx_dl_ud(struct msgb *msg, struct tlv_parsed *tp) { struct bssgp_ud_hdr *budh; - int8_t tfi; /* must be signed */ - uint32_t tlli; uint8_t *data; uint16_t len; - struct gprs_rlcmac_tbf *tbf; char imsi[16] = "000"; budh = (struct bssgp_ud_hdr *)msgb_bssgph(msg); @@ -123,7 +121,7 @@ static int gprs_bssgp_pcu_rx_dl_ud(struct msgb *msg, struct tlv_parsed *tp) data = (uint8_t *) TLVP_VAL(tp, BSSGP_IE_LLC_PDU); len = TLVP_LEN(tp, BSSGP_IE_LLC_PDU); - if (len > sizeof(tbf->llc_frame)) + if (len > sizeof(gprs_rlcmac_tbf::llc_frame)) { LOGP(DBSSGP, LOGL_NOTICE, "BSSGP TLLI=0x%08x Rx UL-UD IE_LLC_PDU too large\n", tlli); return bssgp_tx_status(BSSGP_CAUSE_COND_IE_ERR, NULL, msg); @@ -154,120 +152,7 @@ static int gprs_bssgp_pcu_rx_dl_ud(struct msgb *msg, struct tlv_parsed *tp) LOGP(DBSSGP, LOGL_INFO, "LLC [SGSN -> PCU] = TLLI: 0x%08x IMSI: %s len: %d\n", tlli, imsi, len); - /* check for existing TBF */ - if ((tbf = tbf_by_tlli(tlli, GPRS_RLCMAC_DL_TBF))) { - LOGP(DRLCMAC, LOGL_INFO, "TBF: APPEND TFI: %u TLLI: 0x%08x\n", tbf->tfi, tbf->tlli); - if (tbf->state == GPRS_RLCMAC_WAIT_RELEASE) { - LOGP(DRLCMAC, LOGL_DEBUG, "TBF in WAIT RELEASE state " - "(T3193), so reuse TBF\n"); - memcpy(tbf->llc_frame, data, len); - tbf->llc_length = len; - memset(&tbf->dir.dl, 0, sizeof(tbf->dir.dl)); /* reset - rlc states */ - tbf->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; /* keep - to flags */ - tbf->state_flags &= ~(1 << GPRS_RLCMAC_FLAG_CCCH); - if (!tbf->ms_class && ms_class) - tbf->ms_class = ms_class; - tbf_update(tbf); - gprs_rlcmac_trigger_downlink_assignment(tbf, tbf, NULL); - } else { - /* the TBF exists, so we must write it in the queue - * we prepend lifetime in front of PDU */ - struct timeval *tv; - struct msgb *llc_msg = msgb_alloc(len + sizeof(*tv), - "llc_pdu_queue"); - if (!llc_msg) - return -ENOMEM; - tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv)); - if (the_pcu.bts->force_llc_lifetime) - delay_csec = the_pcu.bts->force_llc_lifetime; - /* keep timestap at 0 for infinite delay */ - if (delay_csec != 0xffff) { - /* calculate timestamp of timeout */ - gettimeofday(tv, NULL); - tv->tv_usec += (delay_csec % 100) * 10000; - tv->tv_sec += delay_csec / 100; - if (tv->tv_usec > 999999) { - tv->tv_usec -= 1000000; - tv->tv_sec++; - } - } - memcpy(msgb_put(llc_msg, len), data, len); - msgb_enqueue(&tbf->llc_queue, llc_msg); - /* set ms class for updating TBF */ - if (!tbf->ms_class && ms_class) - tbf->ms_class = ms_class; - } - } else { - uint8_t trx, ta, ss; - int8_t use_trx; - struct gprs_rlcmac_tbf *old_tbf; - int rc; - - /* check for uplink data, so we copy our informations */ - tbf = tbf_by_tlli(tlli, GPRS_RLCMAC_UL_TBF); - if (tbf && tbf->dir.ul.contention_resolution_done - && !tbf->dir.ul.final_ack_sent) { - use_trx = tbf->trx; - ta = tbf->ta; - ss = 0; - old_tbf = tbf; - } else { - use_trx = -1; - /* we already have an uplink TBF, so we use that TA */ - if (tbf) - ta = tbf->ta; - else { - /* recall TA */ - rc = recall_timing_advance(tlli); - if (rc < 0) { - LOGP(DRLCMAC, LOGL_NOTICE, "TA unknown" - ", assuming 0\n"); - ta = 0; - } else - ta = rc; - } - ss = 1; /* PCH assignment only allows one timeslot */ - old_tbf = NULL; - } - - // Create new TBF (any TRX) - tfi = tfi_find_free(the_pcu.bts, GPRS_RLCMAC_DL_TBF, &trx, use_trx); - if (tfi < 0) { - LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH resource\n"); - /* FIXME: send reject */ - return -EBUSY; - } - /* set number of downlink slots according to multislot class */ - tbf = tbf_alloc(the_pcu.bts, tbf, GPRS_RLCMAC_DL_TBF, tfi, trx, ms_class, - ss); - if (!tbf) { - LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n"); - /* FIXME: send reject */ - return -EBUSY; - } - tbf->tlli = tlli; - tbf->tlli_valid = 1; - tbf->ta = ta; - - LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [DOWNLINK] START TFI: %d TLLI: 0x%08x \n", tbf->tfi, tbf->tlli); - - /* new TBF, so put first frame */ - memcpy(tbf->llc_frame, data, len); - tbf->llc_length = len; - - /* trigger downlink assignment and set state to ASSIGN. - * we don't use old_downlink, so the possible uplink is used - * to trigger downlink assignment. if there is no uplink, - * AGCH is used. */ - gprs_rlcmac_trigger_downlink_assignment(tbf, old_tbf, imsi); - } - - /* store IMSI for debugging purpose */ - strncpy(tbf->meas.imsi, imsi, sizeof(tbf->meas.imsi) - 1); - - return 0; + return tbf_handle(the_pcu.bts, tlli, imsi, ms_class, delay_csec, data, len); } int gprs_bssgp_pcu_rx_paging_ps(struct msgb *msg, struct tlv_parsed *tp) diff --git a/src/tbf.cpp b/src/tbf.cpp new file mode 100644 index 0000000..816fdb8 --- /dev/null +++ b/src/tbf.cpp @@ -0,0 +1,160 @@ +/* Copied from gprs_bssgp_pcu.cpp + * + * Copyright (C) 2012 Ivan Klyuchnikov + * Copyright (C) 2013 by Holger Hans Peter Freyther + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include <tbf.h> +#include <gprs_rlcmac.h> +#include <gprs_debug.h> + +extern "C" { +#include <osmocom/core/msgb.h> +} + +#include <errno.h> +#include <string.h> + +/** + * TODO: split into unit test-able parts... + */ +int tbf_handle(struct gprs_rlcmac_bts *bts, + const uint32_t tlli, const char *imsi, + const uint8_t ms_class, const uint16_t pdu_delay_csec, + const uint8_t *data, const uint16_t len) +{ + struct gprs_rlcmac_tbf *tbf; + int8_t tfi; /* must be signed */ + + /* check for existing TBF */ + if ((tbf = tbf_by_tlli(tlli, GPRS_RLCMAC_DL_TBF))) { + LOGP(DRLCMAC, LOGL_INFO, "TBF: APPEND TFI: %u TLLI: 0x%08x\n", tbf->tfi, tbf->tlli); + if (tbf->state == GPRS_RLCMAC_WAIT_RELEASE) { + LOGP(DRLCMAC, LOGL_DEBUG, "TBF in WAIT RELEASE state " + "(T3193), so reuse TBF\n"); + memcpy(tbf->llc_frame, data, len); + tbf->llc_length = len; + memset(&tbf->dir.dl, 0, sizeof(tbf->dir.dl)); /* reset + rlc states */ + tbf->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK; /* keep + to flags */ + tbf->state_flags &= ~(1 << GPRS_RLCMAC_FLAG_CCCH); + if (!tbf->ms_class && ms_class) + tbf->ms_class = ms_class; + tbf_update(tbf); + gprs_rlcmac_trigger_downlink_assignment(tbf, tbf, NULL); + } else { + /* the TBF exists, so we must write it in the queue + * we prepend lifetime in front of PDU */ + struct timeval *tv; + struct msgb *llc_msg = msgb_alloc(len + sizeof(*tv), + "llc_pdu_queue"); + if (!llc_msg) + return -ENOMEM; + tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv)); + + uint16_t delay_csec; + if (bts->force_llc_lifetime) + delay_csec = bts->force_llc_lifetime; + else + delay_csec = pdu_delay_csec; + /* keep timestap at 0 for infinite delay */ + if (delay_csec != 0xffff) { + /* calculate timestamp of timeout */ + gettimeofday(tv, NULL); + tv->tv_usec += (delay_csec % 100) * 10000; + tv->tv_sec += delay_csec / 100; + if (tv->tv_usec > 999999) { + tv->tv_usec -= 1000000; + tv->tv_sec++; + } + } + memcpy(msgb_put(llc_msg, len), data, len); + msgb_enqueue(&tbf->llc_queue, llc_msg); + /* set ms class for updating TBF */ + if (!tbf->ms_class && ms_class) + tbf->ms_class = ms_class; + } + } else { + uint8_t trx, ta, ss; + int8_t use_trx; + struct gprs_rlcmac_tbf *old_tbf; + int rc; + + /* check for uplink data, so we copy our informations */ + tbf = tbf_by_tlli(tlli, GPRS_RLCMAC_UL_TBF); + if (tbf && tbf->dir.ul.contention_resolution_done + && !tbf->dir.ul.final_ack_sent) { + use_trx = tbf->trx; + ta = tbf->ta; + ss = 0; + old_tbf = tbf; + } else { + use_trx = -1; + /* we already have an uplink TBF, so we use that TA */ + if (tbf) + ta = tbf->ta; + else { + /* recall TA */ + rc = recall_timing_advance(tlli); + if (rc < 0) { + LOGP(DRLCMAC, LOGL_NOTICE, "TA unknown" + ", assuming 0\n"); + ta = 0; + } else + ta = rc; + } + ss = 1; /* PCH assignment only allows one timeslot */ + old_tbf = NULL; + } + + // Create new TBF (any TRX) + tfi = tfi_find_free(bts, GPRS_RLCMAC_DL_TBF, &trx, use_trx); + if (tfi < 0) { + LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH resource\n"); + /* FIXME: send reject */ + return -EBUSY; + } + /* set number of downlink slots according to multislot class */ + tbf = tbf_alloc(bts, tbf, GPRS_RLCMAC_DL_TBF, tfi, trx, ms_class, + ss); + if (!tbf) { + LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n"); + /* FIXME: send reject */ + return -EBUSY; + } + tbf->tlli = tlli; + tbf->tlli_valid = 1; + tbf->ta = ta; + + LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [DOWNLINK] START TFI: %d TLLI: 0x%08x \n", tbf->tfi, tbf->tlli); + + /* new TBF, so put first frame */ + memcpy(tbf->llc_frame, data, len); + tbf->llc_length = len; + + /* trigger downlink assignment and set state to ASSIGN. + * we don't use old_downlink, so the possible uplink is used + * to trigger downlink assignment. if there is no uplink, + * AGCH is used. */ + gprs_rlcmac_trigger_downlink_assignment(tbf, old_tbf, imsi); + } + + /* store IMSI for debugging purpose */ + strncpy(tbf->meas.imsi, imsi, sizeof(tbf->meas.imsi) - 1); + return 0; +} diff --git a/src/tbf.h b/src/tbf.h new file mode 100644 index 0000000..1535e8c --- /dev/null +++ b/src/tbf.h @@ -0,0 +1,27 @@ +/* + * Copyright (C) 2013 by Holger Hans Peter Freyther + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#pragma once + +#include <stdint.h> + +struct gprs_rlcmac_bts; + +int tbf_handle(struct gprs_rlcmac_bts *bts, + const uint32_t tlli, const char *imsi, const uint8_t ms_class, + const uint16_t delay_csec, const uint8_t *data, const uint16_t len); -- 1.8.4.rc3

1 7

[PATCH 1/3] tfi: The tfi_alloc doesn't allocate anything, rename the function
by Holger Hans Peter Freyther 02 Oct '13

02 Oct '13

From: Holger Hans Peter Freyther <holger(a)moiji-mobile.com> Call things by what they do and this function doesn't allocate anything but it is searching for the first unallocated tbf index. --- src/gprs_bssgp_pcu.cpp | 2 +- src/gprs_rlcmac.cpp | 3 ++- src/gprs_rlcmac.h | 3 ++- src/gprs_rlcmac_data.cpp | 4 ++-- 4 files changed, 7 insertions(+), 5 deletions(-) diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp index 6f67f52..4833af8 100644 --- a/src/gprs_bssgp_pcu.cpp +++ b/src/gprs_bssgp_pcu.cpp @@ -233,7 +233,7 @@ static int gprs_bssgp_pcu_rx_dl_ud(struct msgb *msg, struct tlv_parsed *tp) } // Create new TBF (any TRX) - tfi = tfi_alloc(the_pcu.bts, GPRS_RLCMAC_DL_TBF, &trx, use_trx); + tfi = tfi_find_free(the_pcu.bts, GPRS_RLCMAC_DL_TBF, &trx, use_trx); if (tfi < 0) { LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH resource\n"); /* FIXME: send reject */ diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp index 8874983..913ae48 100644 --- a/src/gprs_rlcmac.cpp +++ b/src/gprs_rlcmac.cpp @@ -2,6 +2,7 @@ * * Copyright (C) 2012 Ivan Klyuchnikov * Copyright (C) 2012 Andreas Eversberg <jolly(a)eversberg.eu> + * Copyright (C) 2013 by Holger Hans Peter Freyther * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -176,7 +177,7 @@ void debug_diagram(int diag, const char *format, ...) /* FIXME: spread ressources over multiple TRX. Also add option to use same * TRX in case of existing TBF for TLLI in the other direction. */ /* search for free TFI and return TFI, TRX */ -int tfi_alloc(struct gprs_rlcmac_bts *bts, enum gprs_rlcmac_tbf_direction dir, +int tfi_find_free(struct gprs_rlcmac_bts *bts, enum gprs_rlcmac_tbf_direction dir, uint8_t *_trx, int8_t use_trx) { struct gprs_rlcmac_pdch *pdch; diff --git a/src/gprs_rlcmac.h b/src/gprs_rlcmac.h index ac437f5..4329cb8 100644 --- a/src/gprs_rlcmac.h +++ b/src/gprs_rlcmac.h @@ -1,6 +1,7 @@ /* gprs_rlcmac.h * * Copyright (C) 2012 Ivan Klyuchnikov + * Copyright (C) 2013 by Holger Hans Peter Freyther * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -309,7 +310,7 @@ int sba_alloc(uint8_t *_trx, uint8_t *_ts, uint32_t *_fn, uint8_t ta); struct gprs_rlcmac_sba *sba_find(uint8_t trx, uint8_t ts, uint32_t fn); -int tfi_alloc(struct gprs_rlcmac_bts *bts, enum gprs_rlcmac_tbf_direction dir, +int tfi_find_free(struct gprs_rlcmac_bts *bts, enum gprs_rlcmac_tbf_direction dir, uint8_t *_trx, int8_t use_trx); struct gprs_rlcmac_tbf *tbf_alloc(struct gprs_rlcmac_bts *bts, diff --git a/src/gprs_rlcmac_data.cpp b/src/gprs_rlcmac_data.cpp index 4d5acb9..ff5274f 100644 --- a/src/gprs_rlcmac_data.cpp +++ b/src/gprs_rlcmac_data.cpp @@ -239,7 +239,7 @@ static struct gprs_rlcmac_tbf *alloc_ul_tbf(int8_t use_trx, uint8_t ms_class, uint8_t tfi; /* create new TBF, use sme TRX as DL TBF */ - tfi = tfi_alloc(bts, GPRS_RLCMAC_UL_TBF, &trx, use_trx); + tfi = tfi_find_free(bts, GPRS_RLCMAC_UL_TBF, &trx, use_trx); if (tfi < 0) { LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n"); /* FIXME: send reject */ @@ -1174,7 +1174,7 @@ int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta) "(AGCH)\n"); } else { // Create new TBF - tfi = tfi_alloc(bts, GPRS_RLCMAC_UL_TBF, &trx, -1); + tfi = tfi_find_free(bts, GPRS_RLCMAC_UL_TBF, &trx, -1); if (tfi < 0) { LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n"); /* FIXME: send reject */ -- 1.8.3.2

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osmocom-net-gprs October 2013