<p>neels <strong>submitted</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/osmo-bsc/+/20355">View Change</a></p><div style="white-space:pre-wrap">Approvals:
Jenkins Builder: Verified
laforge: Looks good to me, approved
pespin: Looks good to me, but someone else must approve
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">LCS: implement re-use of existing A-interface conn<br><br>Location Services brings a new scenario to OsmoBSC: the MSC may create an<br>A-interface conn for a subscriber without an lchan being established (N-CONNECT<br>from MSC to BSC, so far only for an incoming inter-BSC handover).<br><br>If an MS becomes active while an A-interface conn is already established,<br>associate with an existing conn.<br><br>Change-Id: I42290f519a419ed7e8dd02a5ed0a5261b30a51e6<br>---<br>M include/osmocom/bsc/osmo_bsc_sigtran.h<br>M src/osmo-bsc/gsm_08_08.c<br>M src/osmo-bsc/osmo_bsc_sigtran.c<br>3 files changed, 69 insertions(+), 23 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/include/osmocom/bsc/osmo_bsc_sigtran.h b/include/osmocom/bsc/osmo_bsc_sigtran.h</span><br><span>index dc86fad..faaceb2 100644</span><br><span>--- a/include/osmocom/bsc/osmo_bsc_sigtran.h</span><br><span>+++ b/include/osmocom/bsc/osmo_bsc_sigtran.h</span><br><span>@@ -26,6 +26,7 @@</span><br><span> /* Allocate resources to make a new connection oriented sigtran connection</span><br><span> * (not the connection ittself!) */</span><br><span> enum bsc_con osmo_bsc_sigtran_new_conn(struct gsm_subscriber_connection *conn, struct bsc_msc_data *msc);</span><br><span style="color: hsl(120, 100%, 40%);">+struct gsm_subscriber_connection *bsc_conn_by_bsub(struct bsc_subscr *bsub);</span><br><span> </span><br><span> /* Open a new connection oriented sigtran connection */</span><br><span> int osmo_bsc_sigtran_open_conn(struct gsm_subscriber_connection *conn, struct msgb *msg);</span><br><span>diff --git a/src/osmo-bsc/gsm_08_08.c b/src/osmo-bsc/gsm_08_08.c</span><br><span>index 41fc230..a4b53f0 100644</span><br><span>--- a/src/osmo-bsc/gsm_08_08.c</span><br><span>+++ b/src/osmo-bsc/gsm_08_08.c</span><br><span>@@ -363,7 +363,7 @@</span><br><span> /*! MS->MSC: New MM context with L3 payload. */</span><br><span> int bsc_compl_l3(struct gsm_lchan *lchan, struct msgb *msg, uint16_t chosen_channel)</span><br><span> {</span><br><span style="color: hsl(0, 100%, 40%);">- struct gsm_subscriber_connection *conn;</span><br><span style="color: hsl(120, 100%, 40%);">+ struct gsm_subscriber_connection *conn = NULL;</span><br><span> struct bsc_subscr *bsub = NULL;</span><br><span> struct bsc_msc_data *paged_from_msc;</span><br><span> enum bsc_paging_reason paging_reasons;</span><br><span>@@ -382,7 +382,7 @@</span><br><span> </span><br><span> if (msgb_l3len(msg) < sizeof(*gh)) {</span><br><span> LOGP(DRSL, LOGL_ERROR, "There is no GSM48 header here.\n");</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span> }</span><br><span> </span><br><span> gh = msgb_l3(msg);</span><br><span>@@ -392,6 +392,9 @@</span><br><span> bts = lchan->ts->trx->bts;</span><br><span> OSMO_ASSERT(bts);</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* Normally, if an lchan has no conn yet, it is an all new Complete Layer 3, and we allocate a new conn on the</span><br><span style="color: hsl(120, 100%, 40%);">+ * A-interface. But there are cases where a conn on A already exists for this subscriber (e.g. Perform Location</span><br><span style="color: hsl(120, 100%, 40%);">+ * Request on IDLE MS). The Mobile Identity tells us whether that is the case. */</span><br><span> if (osmo_mobile_identity_decode_from_l3(&mi, msg, false)) {</span><br><span> LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "Cannot extract Mobile Identity: %s\n",</span><br><span> msgb_hexdump_c(OTC_SELECT, msg));</span><br><span>@@ -405,11 +408,19 @@</span><br><span> bsub = bsc_subscr_find_or_create_by_mi(bsc_gsmnet->bsc_subscribers, &mi, __func__);</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* allocate a new connection */</span><br><span style="color: hsl(0, 100%, 40%);">- conn = bsc_subscr_con_allocate(bsc_gsmnet);</span><br><span style="color: hsl(120, 100%, 40%);">+ /* If this Mobile Identity already has an active bsc_subscr, look whether there also is an active A-interface</span><br><span style="color: hsl(120, 100%, 40%);">+ * conn for this subscriber. This may be the case during a Perform Location Request (LCS) from the MSC that</span><br><span style="color: hsl(120, 100%, 40%);">+ * started on an IDLE MS, and now the MS is becoming active. Associate with the existing conn. */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (bsub)</span><br><span style="color: hsl(120, 100%, 40%);">+ conn = bsc_conn_by_bsub(bsub);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> if (!conn) {</span><br><span style="color: hsl(0, 100%, 40%);">- LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "Failed to allocate conn\n");</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* Typical Complete Layer 3 with a new conn being established. */</span><br><span style="color: hsl(120, 100%, 40%);">+ conn = bsc_subscr_con_allocate(bsc_gsmnet);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!conn) {</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "Failed to allocate conn\n");</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> }</span><br><span> if (bsub) {</span><br><span> /* We got the conn either from new allocation, or by searching for it by bsub. So: */</span><br><span>@@ -420,6 +431,7 @@</span><br><span> }</span><br><span> bsc_subscr_put(bsub, __func__);</span><br><span> }</span><br><span style="color: hsl(120, 100%, 40%);">+ /* Associate lchan with the conn, and set the id string for logging */</span><br><span> gscon_change_primary_lchan(conn, lchan);</span><br><span> gscon_update_id(conn);</span><br><span> </span><br><span>@@ -454,24 +466,44 @@</span><br><span> }</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* find the MSC link we want to use */</span><br><span style="color: hsl(0, 100%, 40%);">- if (paged_from_msc)</span><br><span style="color: hsl(0, 100%, 40%);">- msc = paged_from_msc;</span><br><span style="color: hsl(0, 100%, 40%);">- else</span><br><span style="color: hsl(0, 100%, 40%);">- msc = bsc_find_msc(conn, &mi, is_emerg, is_lu_from_other_plmn(msg));</span><br><span style="color: hsl(0, 100%, 40%);">- if (!msc) {</span><br><span style="color: hsl(0, 100%, 40%);">- LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "%s%s: No suitable MSC for this Complete Layer 3 request found\n",</span><br><span style="color: hsl(0, 100%, 40%);">- osmo_mobile_identity_to_str_c(OTC_SELECT, &mi), is_emerg ? " FOR EMERGENCY CALL" : "");</span><br><span style="color: hsl(0, 100%, 40%);">- rc = -1;</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(0, 100%, 40%);">- }</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!conn->sccp.msc) {</span><br><span style="color: hsl(120, 100%, 40%);">+ /* The conn was just allocated, and no target MSC has been picked for it yet. */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (paged_from_msc)</span><br><span style="color: hsl(120, 100%, 40%);">+ msc = paged_from_msc;</span><br><span style="color: hsl(120, 100%, 40%);">+ else</span><br><span style="color: hsl(120, 100%, 40%);">+ msc = bsc_find_msc(conn, &mi, is_emerg, is_lu_from_other_plmn(msg));</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!msc) {</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR,</span><br><span style="color: hsl(120, 100%, 40%);">+ "%s%s: No suitable MSC for this Complete Layer 3 request found\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_mobile_identity_to_str_c(OTC_SELECT, &mi),</span><br><span style="color: hsl(120, 100%, 40%);">+ is_emerg ? " FOR EMERGENCY CALL" : "");</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* allocate resource for a new connection */</span><br><span style="color: hsl(0, 100%, 40%);">- if (osmo_bsc_sigtran_new_conn(conn, msc) != BSC_CON_SUCCESS)</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* allocate resource for a new connection */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (osmo_bsc_sigtran_new_conn(conn, msc) != BSC_CON_SUCCESS)</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span style="color: hsl(120, 100%, 40%);">+ } else if (paged_from_msc && conn->sccp.msc != paged_from_msc) {</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR,</span><br><span style="color: hsl(120, 100%, 40%);">+ "%s%s: there is a conn to MSC %u, but there is a pending Paging request from MSC %u\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_mobile_identity_to_str_c(OTC_SELECT, &mi),</span><br><span style="color: hsl(120, 100%, 40%);">+ is_emerg ? " FOR EMERGENCY CALL" : "",</span><br><span style="color: hsl(120, 100%, 40%);">+ conn->sccp.msc->nr, paged_from_msc->nr);</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ OSMO_ASSERT(conn->sccp.msc);</span><br><span> </span><br><span> parse_powercap(conn, msg);</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* If the Paging was issued only by OsmoBSC for LCS, don't bother to establish Layer 3 to the MSC. */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (paged_from_msc && !(paging_reasons & BSC_PAGING_FROM_CN)) {</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_COMPL_L3(pdisc, mtype, LOGL_DEBUG,</span><br><span style="color: hsl(120, 100%, 40%);">+ "%s%s: Paging was for Perform Location Request only, not establishing Layer 3\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_mobile_identity_to_str_c(OTC_SELECT, &mi),</span><br><span style="color: hsl(120, 100%, 40%);">+ is_emerg ? " FOR EMERGENCY CALL" : "");</span><br><span style="color: hsl(120, 100%, 40%);">+ rc = 0;</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* Send the Create Layer 3. */</span><br><span> use_scl = NULL;</span><br><span> if (gscon_is_aoip(conn)) {</span><br><span>@@ -486,19 +518,19 @@</span><br><span> /* should never happen */</span><br><span> LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "%s: internal error: BTS without identity\n",</span><br><span> osmo_mobile_identity_to_str_c(OTC_SELECT, &mi));</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span> }</span><br><span> create_l3 = gsm0808_create_layer3_2(msg, cgi, use_scl);</span><br><span> if (!create_l3) {</span><br><span> LOG_COMPL_L3(pdisc, mtype, LOGL_ERROR, "%s: Failed to compose Create Layer 3 message\n",</span><br><span> osmo_mobile_identity_to_str_c(OTC_SELECT, &mi));</span><br><span style="color: hsl(0, 100%, 40%);">- goto early_fail;</span><br><span style="color: hsl(120, 100%, 40%);">+ goto early_exit;</span><br><span> }</span><br><span> rc = osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_MO_COMPL_L3, create_l3);</span><br><span> if (!rc)</span><br><span> release_lchan = false;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-early_fail:</span><br><span style="color: hsl(120, 100%, 40%);">+early_exit:</span><br><span> if (release_lchan)</span><br><span> lchan_release(lchan, false, true, RSL_ERR_EQUIPMENT_FAIL);</span><br><span> log_set_context(LOG_CTX_BSC_SUBSCR, NULL);</span><br><span>diff --git a/src/osmo-bsc/osmo_bsc_sigtran.c b/src/osmo-bsc/osmo_bsc_sigtran.c</span><br><span>index e13a8f7..e0c24ef 100644</span><br><span>--- a/src/osmo-bsc/osmo_bsc_sigtran.c</span><br><span>+++ b/src/osmo-bsc/osmo_bsc_sigtran.c</span><br><span>@@ -63,6 +63,19 @@</span><br><span> return NULL;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+struct gsm_subscriber_connection *bsc_conn_by_bsub(struct bsc_subscr *bsub)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ struct gsm_subscriber_connection *conn;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!bsub)</span><br><span style="color: hsl(120, 100%, 40%);">+ return NULL;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {</span><br><span style="color: hsl(120, 100%, 40%);">+ if (conn->bsub == bsub)</span><br><span style="color: hsl(120, 100%, 40%);">+ return conn;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ return NULL;</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* Pick a free connection id */</span><br><span> static int pick_free_conn_id(const struct bsc_msc_data *msc)</span><br><span> {</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-bsc/+/20355">change 20355</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/c/osmo-bsc/+/20355"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: osmo-bsc </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I42290f519a419ed7e8dd02a5ed0a5261b30a51e6 </div>
<div style="display:none"> Gerrit-Change-Number: 20355 </div>
<div style="display:none"> Gerrit-PatchSet: 4 </div>
<div style="display:none"> Gerrit-Owner: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>