Review at  https://gerrit.osmocom.org/6602

ensure unique CellIDs in HNB-GW

If we receive a HNB-REGISTER-REQ with a cell ID which is already used
by another registered NNB, log an error and send HNB-REGISTER-REJECT.

Tested manually by running two 'hnb-test' programs concurrently (they
need to listen on different telnet ports; this port is hard-coded so
I compiled two different hnb-test binaries).
Then I issued the 'hnbap hnb register' command on the telnet interface
of each, and verified that the correct action is logged by osmo-hnbgw.
Both hnb-test programs can connect, but only one of them can register
at a time. Killing a registered 'hnb-test' program terminates its
connection and allows the previously rejected one to register.

The new rejection log message looks like this:
 hnbgw_hnbap.c:429 rejecting HNB-REGISTER-REQ with duplicate cell
 identity MCC=901,MNC=99,LAC=49406,RAC=66,SAC=43947,CID=182250155
 from (r=127.0.0.1:42828<->l=127.0.0.1:29169)

Change-Id: Iffd441eb2b6b75dfbe001b49b01bea015ca6e11c
Related: OS#2789
---
M include/osmocom/iuh/hnbgw.h
M src/hnbgw_hnbap.c
2 files changed, 51 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-iuh refs/changes/02/6602/1

diff --git a/include/osmocom/iuh/hnbgw.h b/include/osmocom/iuh/hnbgw.h
index 094f31f..db49dc1 100644
--- a/include/osmocom/iuh/hnbgw.h
+++ b/include/osmocom/iuh/hnbgw.h
@@ -97,6 +97,10 @@
        /*! SCTP stream ID for RUA */
        uint16_t rua_stream;
 
+       /*! True if a HNB-REGISTER-REQ from this HNB has been accepted. Note 
that
+        * this entire data structure is freed if the HNB sends 
HNB-DE-REGISTER-REQ. */
+       bool hnb_registered;
+
        /* linked list of hnbgw_context_map */
        struct llist_head map_list;
 };
diff --git a/src/hnbgw_hnbap.c b/src/hnbgw_hnbap.c
index 8fba13c..c9a8807 100644
--- a/src/hnbgw_hnbap.c
+++ b/src/hnbgw_hnbap.c
@@ -20,6 +20,7 @@
 
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/utils.h>
+#include <osmocom/core/socket.h>
 #include <osmocom/gsm/gsm48.h>
 #include <osmocom/netif/stream.h>
 
@@ -46,6 +47,37 @@
        osmo_stream_srv_send(ctx->conn, msg);
 
        return 0;
+}
+
+static int hnbgw_tx_hnb_register_rej(struct hnb_context *ctx)
+{
+       HNBRegisterReject_t reject_out;
+       HNBRegisterRejectIEs_t reject;
+       struct msgb *msg;
+       int rc;
+
+       reject.presenceMask = 0,
+       reject.cause.present = Cause_PR_radioNetwork;
+       reject.cause.choice.radioNetwork = CauseRadioNetwork_unspecified;
+
+       /* encode the Information Elements */
+       memset(&reject_out, 0, sizeof(reject_out));
+       rc = hnbap_encode_hnbregisterrejecties(&reject_out,  &reject);
+       if (rc < 0) {
+               LOGP(DHNBAP, LOGL_ERROR, "Failure to encode HNB-REGISTER-REJECT 
to %s: rc=%d\n",
+                    ctx->identity_info, rc);
+               return rc;
+       }
+
+       /* generate a successfull outcome PDU */
+       msg = hnbap_generate_unsuccessful_outcome(ProcedureCode_id_HNBRegister,
+                                                 Criticality_reject,
+                                                 &asn_DEF_HNBRegisterReject,
+                                                 &reject_out);
+
+       ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_HNBRegisterReject, &reject_out);
+
+       return hnbgw_hnbap_tx(ctx, msg);
 }
 
 static int hnbgw_tx_hnb_register_acc(struct hnb_context *ctx)
@@ -368,6 +400,7 @@
 
 static int hnbgw_rx_hnb_register_req(struct hnb_context *ctx, ANY_t *in)
 {
+       struct hnb_context *hnb;
        HNBRegisterRequestIEs_t ies;
        int rc;
 
@@ -387,6 +420,20 @@
        ctx->id.cid = asn1bitstr_to_u28(&ies.cellIdentity);
        gsm48_mcc_mnc_from_bcd(ies.plmNidentity.buf, &ctx->id.mcc, 
&ctx->id.mnc);
 
+       llist_for_each_entry(hnb, &ctx->gw->hnb_list, list) {
+               if (hnb->hnb_registered && ctx != hnb && memcmp(&ctx->id, 
&hnb->id, sizeof(ctx->id)) == 0) {
+                       struct osmo_fd *ofd = 
osmo_stream_srv_get_ofd(ctx->conn);
+                       char *name = osmo_sock_get_name(ctx, ofd->fd);
+                       LOGP(DHNBAP, LOGL_ERROR, "rejecting HNB-REGISTER-REQ 
with duplicate cell identity "
+                            "MCC=%u,MNC=%u,LAC=%u,RAC=%u,SAC=%u,CID=%u from 
%s\n",
+                            ctx->id.mcc, ctx->id.mnc, ctx->id.lac, 
ctx->id.rac, ctx->id.sac, ctx->id.cid, name);
+                       talloc_free(name);
+                       return hnbgw_tx_hnb_register_rej(ctx);
+               }
+       }
+
+       ctx->hnb_registered = true;
+
        DEBUGP(DHNBAP, "HNB-REGISTER-REQ from %s\n", ctx->identity_info);
 
        /* Send HNBRegisterAccept */

-- 
To view, visit https://gerrit.osmocom.org/6602
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Iffd441eb2b6b75dfbe001b49b01bea015ca6e11c
Gerrit-PatchSet: 1
Gerrit-Project: osmo-iuh
Gerrit-Branch: master
Gerrit-Owner: Stefan Sperling <ssperl...@sysmocom.de>

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