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lchan activation: add explicit encryption info to activation 

For intra-BSC handover, the previous encryption is copied from the old lchan,
which of course is not available during inter-BSC handover.  Hence the lchan
activation info needs to include an explicit encryption information, and we
must not rely on the presence of the previous lchan to copy encryption
information from.

Add struct lchan_activate_info.encr to allow passing encryption info through
lchan_activate() without requiring a previous struct gsm_lchan to be present.

Instead of copying from the old lchan, always copy encryption info to
lchan_activate_info, and during activation, just before sending the Channel
Activation, copy the lchan_activate_info.encr to the new lchan.

This prepares for upcoming I5b269f50bd2092516bfdf87746196983d3ac49d1 which
obtains the encryption information from an intra-BSC-incoming Handover Request
message.

Related: OS#3842
Related: I5b269f50bd2092516bfdf87746196983d3ac49d1
Change-Id: Ib3d259a5711add65ab7298bfa3977855a17a1642
This commit is contained in:
Neels Hofmeyr 2019-03-15 02:49:18 +01:00
parent e94ce889f0
commit 58cf1b1f66
4 changed files with 10 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/osmocom/bsc/gsm_data.h
View File

@ -528,6 +528,7 @@ struct lchan_activate_info {
/* This always is for a specific lchan, so its lchan->type indicates full or half rate.
* When a dyn TS was selected, the lchan->type has been set to the desired rate. */
enum gsm48_chan_mode chan_mode;
struct gsm_encr encr;
/* AMR config */
uint16_t s15_s0;
bool requires_voice_stream;

1
src/osmo-bsc/assignment_fsm.c
View File

@ -484,6 +484,7 @@ void assignment_fsm_start(struct gsm_subscriber_connection *conn, struct gsm_bts
.activ_for = FOR_ASSIGNMENT,
.for_conn = conn,
.chan_mode = conn->lchan->ch_mode_rate.chan_mode,
.encr = conn->lchan->encr,
.s15_s0 = conn->lchan->ch_mode_rate.s15_s0,
.requires_voice_stream = conn->assignment.requires_voice_stream,
.msc_assigned_cic = req->msc_assigned_cic,

1
src/osmo-bsc/handover_fsm.c
View File

@ -358,6 +358,7 @@ static void handover_start_intra_bsc(struct gsm_subscriber_connection *conn)
.activ_for = FOR_HANDOVER,
.for_conn = conn,
.chan_mode = conn->lchan->tch_mode,
.encr = conn->lchan->encr,
.requires_voice_stream = conn->lchan->mgw_endpoint_ci_bts ? true : false,
.msc_assigned_cic = conn->ho.inter_bsc_in.msc_assigned_cic,
.re_use_mgw_endpoint_from_lchan = conn->lchan,

17
src/osmo-bsc/lchan_fsm.c
View File

@ -518,14 +518,6 @@ static void lchan_fsm_wait_ts_ready_onenter(struct osmo_fsm_inst *fi, uint32_t p
lchan->conn = info->for_conn;
if (old_lchan)
lchan->encr = old_lchan->encr;
else {
lchan->encr = (struct gsm_encr){
.alg_id = RSL_ENC_ALG_A5(0), /* no encryption */
};
}
/* If there is a previous lchan, and the new lchan is on the same cell as previous one,
* take over power and TA values. Otherwise, use max power and zero TA. */
if (old_lchan && old_lchan->ts->trx->bts == bts) {
@ -585,14 +577,17 @@ static void lchan_fsm_wait_ts_ready_onenter(struct osmo_fsm_inst *fi, uint32_t p
use_mgwep_ci = lchan_use_mgw_endpoint_ci_bts(lchan);
LOG_LCHAN(lchan, LOGL_INFO,
"Activation requested: %s voice=%s MGW-ci=%s type=%s tch-mode=%s\n",
"Activation requested: %s voice=%s MGW-ci=%s type=%s tch-mode=%s encr-alg=A5/%u ck=%s\n",
lchan_activate_mode_name(lchan->activate.info.activ_for),
lchan->activate.info.requires_voice_stream ? "yes" : "no",
lchan->activate.info.requires_voice_stream ?
(use_mgwep_ci ? mgwep_ci_name(use_mgwep_ci) : "new")
: "none",
gsm_lchant_name(lchan->type),
gsm48_chan_mode_name(lchan->tch_mode));
gsm48_chan_mode_name(lchan->tch_mode),
(lchan->activate.info.encr.alg_id ? : 1)-1,
lchan->activate.info.encr.key_len ? osmo_hexdump_nospc(lchan->activate.info.encr.key,
lchan->activate.info.encr.key_len) : "none");
/* Ask for the timeslot to make ready for this lchan->type.
* We'll receive LCHAN_EV_TS_READY or LCHAN_EV_TS_ERROR in response. */
@ -657,6 +652,8 @@ static void lchan_fsm_wait_activ_ack_onenter(struct osmo_fsm_inst *fi, uint32_t
break;
}
lchan->encr = lchan->activate.info.encr;
rc = rsl_tx_chan_activ(lchan, act_type, ho_ref);
if (rc)
lchan_fail_to(LCHAN_ST_UNUSED, "Tx Chan Activ failed: %s (%d)", strerror(-rc), rc);