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)

This change depends on a new API in libosmo-netif, which is added in
https://gerrit.osmocom.org/#/c/6844/

Change-Id: Iffd441eb2b6b75dfbe001b49b01bea015ca6e11c
Depends: I8ed78fe39c463e9018756700d13ee5ebe003b57f
Related: OS#2789
This commit is contained in:
Stefan Sperling 2018-02-19 17:02:12 +01:00 committed by Harald Welte
parent e1c01a0262
commit c964a2cfa1
3 changed files with 73 additions and 6 deletions

View File

@ -97,6 +97,10 @@ struct hnb_context {
/*! 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;
};
@ -157,7 +161,7 @@ struct ue_context *ue_context_alloc(struct hnb_context *hnb, const char *imsi,
void ue_context_free(struct ue_context *ue);
struct hnb_context *hnb_context_alloc(struct hnb_gw *gw, struct osmo_stream_srv_link *link, int new_fd);
void hnb_context_release(struct hnb_context *ctx);
void hnb_context_release(struct hnb_context *ctx, bool destroy_conn);
void hnbgw_vty_init(struct hnb_gw *gw, void *tall_ctx);
int hnbgw_vty_go_parent(struct vty *vty);

View File

@ -204,6 +204,12 @@ void ue_context_free(struct ue_context *ue)
}
static int hnb_close_cb(struct osmo_stream_srv *conn)
{
struct hnb_context *hnb = osmo_stream_srv_get_data(conn);
/* This connection is about to be closed. Destroy the HNB context now. */
if (hnb)
hnb_context_release(hnb, false);
return 0;
}
@ -228,10 +234,10 @@ static int hnb_read_cb(struct osmo_stream_srv *conn)
} else if (rc < 0) {
LOGP(DMAIN, LOGL_ERROR, "Error during sctp_recvmsg()\n");
/* FIXME: clean up after disappeared HNB */
hnb_context_release(hnb);
hnb_context_release(hnb, true);
goto out;
} else if (rc == 0) {
hnb_context_release(hnb);
hnb_context_release(hnb, true);
rc = -1;
goto out;
@ -288,7 +294,7 @@ struct hnb_context *hnb_context_alloc(struct hnb_gw *gw, struct osmo_stream_srv_
return ctx;
}
void hnb_context_release(struct hnb_context *ctx)
void hnb_context_release(struct hnb_context *ctx, bool destroy_conn)
{
struct hnbgw_context_map *map, *map2;
@ -305,7 +311,9 @@ void hnb_context_release(struct hnb_context *ctx)
context_map_deactivate(map);
}
ue_context_free_by_hnb(ctx->gw, ctx);
osmo_stream_srv_destroy(ctx->conn);
if (destroy_conn)
osmo_stream_srv_destroy(ctx->conn);
talloc_free(ctx);
}

View File

@ -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>
@ -48,6 +49,45 @@ static int hnbgw_hnbap_tx(struct hnb_context *ctx, struct msgb *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);
rc = hnbgw_hnbap_tx(ctx, msg);
if (rc == 0) {
/* Tell libosmo-netif to destroy this connection when it is done
* sending our HNB-REGISTER-REJECT response. */
osmo_stream_srv_set_flush_and_destroy(ctx->conn);
} else {
/* The message was not queued. Destroy the connection right away. */
hnb_context_release(ctx, true);
}
}
static int hnbgw_tx_hnb_register_acc(struct hnb_context *ctx)
{
HNBRegisterAccept_t accept_out;
@ -361,13 +401,14 @@ static int hnbgw_rx_hnb_deregister(struct hnb_context *ctx, ANY_t *in)
hnbap_cause_str(&ies.cause));
hnbap_free_hnbde_registeries(&ies);
hnb_context_release(ctx);
hnb_context_release(ctx, true);
return 0;
}
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 +428,20 @@ static int hnbgw_rx_hnb_register_req(struct hnb_context *ctx, ANY_t *in)
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 */