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-rw-r--r--openbsc/src/libmsc/a_iface.c214
1 files changed, 187 insertions, 27 deletions
diff --git a/openbsc/src/libmsc/a_iface.c b/openbsc/src/libmsc/a_iface.c
index 869cd7887..dcbb5aad7 100644
--- a/openbsc/src/libmsc/a_iface.c
+++ b/openbsc/src/libmsc/a_iface.c
@@ -37,12 +37,94 @@
#include <openbsc/mgcpgw_client.h>
#include <osmocom/core/byteswap.h>
#include <osmocom/sccp/sccp_types.h>
+#include <openbsc/a_reset.h>
+#include <openbsc/osmo_msc.h>
/* A pointer to the GSM network we work with. By the current paradigm,
* there can only be one gsm_network per MSC. The pointer is set once
* when calling a_init() */
static struct gsm_network *gsm_network = NULL;
+/* A struct to track currently active connections. We need that information
+ * to handle failure sitautions. In case of a problem, we must know which
+ * connections are currently open and which BSC is responsible. We also need
+ * the data to perform our connection checks (a_reset). All other logic will
+ * look at the connection ids and addresses that are supplied by the
+ * primitives */
+struct bsc_conn {
+ struct llist_head list;
+ struct osmo_sccp_addr called_addr; /* BSC (remote) */
+ struct osmo_sccp_addr calling_addr; /* MSC (local) */
+ uint32_t conn_id; /* Connection identifier */
+};
+
+/* Internal list with connections we currently maintain. This
+ * list is of type struct bsc_conn (see above) */
+static LLIST_HEAD(active_connections);
+
+/* Record info of a new active connection in the active connection list */
+static void record_bsc_con(void *ctx, struct osmo_sccp_addr *called_addr, struct osmo_sccp_addr *calling_addr,
+ uint32_t conn_id)
+{
+ struct bsc_conn *conn;
+
+ conn = talloc_zero(ctx, struct bsc_conn);
+ OSMO_ASSERT(conn);
+
+ memcpy(&conn->called_addr, called_addr, sizeof(*called_addr));
+ memcpy(&conn->calling_addr, calling_addr, sizeof(*calling_addr));
+ conn->conn_id = conn_id;
+
+ llist_add_tail(&conn->list, &active_connections);
+}
+
+/* Delete info of a closed connection from the active connection list */
+void a_delete_bsc_con(uint32_t conn_id)
+{
+ struct bsc_conn *conn;
+ struct bsc_conn *conn_temp;
+
+ llist_for_each_entry_safe(conn, conn_temp, &active_connections, list) {
+ if (conn->conn_id == conn_id) {
+ llist_del(&conn->list);
+ talloc_free(conn);
+ }
+ }
+}
+
+/* Check if a specified connection id has an active SCCP connection */
+static bool check_connection_active(uint32_t conn_id)
+{
+ struct bsc_conn *conn;
+
+ /* Find the address for the current connection id */
+ llist_for_each_entry(conn, &active_connections, list) {
+ if (conn->conn_id == conn_id) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/* Get the reset context for a specifiec calling (BSC) address */
+static struct a_reset_ctx *get_reset_ctx_by_sccp_addr(struct osmo_sccp_addr *addr)
+{
+ struct bsc_context *bsc_ctx;
+
+ if (!addr)
+ return NULL;
+
+ llist_for_each_entry(bsc_ctx, &gsm_network->a.bscs, list) {
+ if (memcmp(&bsc_ctx->bsc_addr, addr, sizeof(*addr)) == 0)
+ return bsc_ctx->reset;
+ }
+
+ LOGP(DMSC, LOGL_ERROR, "The calling BSC (%s) is unknown to this MSC ...\n",
+ osmo_sccp_addr_dump(addr));
+ return NULL;
+}
+
/* Send DTAP message via A-interface */
int a_iface_tx_dtap(struct msgb *msg)
{
@@ -107,9 +189,9 @@ int a_iface_tx_cipher_mode(struct gsm_subscriber_connection *conn,
/* Page a subscriber via A-interface */
int a_iface_tx_paging(const char *imsi, uint32_t tmsi, uint16_t lac)
{
- struct a_bsc_addr *addr;
- struct llist_head *bsc_addr_list = get_bsc_addr_list();
+ struct bsc_context *bsc_ctx;
struct gsm0808_cell_id_list cil;
+ struct msgb *msg;
int page_count = 0;
cil.id_discr = CELL_IDENT_LAC;
@@ -117,16 +199,26 @@ int a_iface_tx_paging(const char *imsi, uint32_t tmsi, uint16_t lac)
cil.id_list_len = 1;
/* Deliver paging request to all known BSCs */
- llist_for_each_entry(addr, bsc_addr_list, list) {
- LOGP(DMSC, LOGL_DEBUG, "Passing paging message from MSC to BSC %s (imsi=%s, tmsi=0x%08x, lac=%u)\n",
- osmo_sccp_addr_dump(&addr->calling_addr), imsi, tmsi, lac);
- osmo_sccp_tx_unitdata_msg(addr->scu, &addr->called_addr, &addr->calling_addr,
- gsm0808_create_paging(imsi, &tmsi, &cil, NULL));
- page_count++;
+ llist_for_each_entry(bsc_ctx, &gsm_network->a.bscs, list) {
+ if (a_reset_conn_ready(bsc_ctx->reset)) {
+ LOGP(DMSC, LOGL_DEBUG,
+ "Passing paging message from MSC %s to BSC %s (imsi=%s, tmsi=0x%08x, lac=%u)\n",
+ osmo_sccp_addr_dump(&bsc_ctx->msc_addr),
+ osmo_sccp_addr_dump(&bsc_ctx->bsc_addr), imsi, tmsi, lac);
+ msg = gsm0808_create_paging(imsi, &tmsi, &cil, NULL);
+ osmo_sccp_tx_unitdata_msg(bsc_ctx->sccp_user,
+ &bsc_ctx->msc_addr, &bsc_ctx->bsc_addr, msg);
+ page_count++;
+ } else {
+ LOGP(DMSC, LOGL_DEBUG,
+ "Connection down, dropping paging from MSC %s to BSC %s (imsi=%s, tmsi=0x%08x, lac=%u)\n",
+ osmo_sccp_addr_dump(&bsc_ctx->msc_addr),
+ osmo_sccp_addr_dump(&bsc_ctx->bsc_addr), imsi, tmsi, lac);
+ }
}
if (page_count <= 0)
- LOGP(DMSC, LOGL_ERROR, "Could not deliver paging because no BSC is available!\n");
+ LOGP(DMSC, LOGL_ERROR, "Could not deliver paging because none of the associated BSCs is available!\n");
return page_count;
}
@@ -303,24 +395,51 @@ int a_iface_tx_assignment(struct gsm_trans *trans)
return osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg);
}
-/* Check if we already know this BSC from a successfuly executed reset procedure. */
-static bool test_bsc_known(struct osmo_sccp_addr *bsc_addr)
+/* Callback function: Close all open connections */
+static void a_reset_cb(void *priv)
{
- struct a_bsc_addr *addr;
- struct llist_head *bsc_addr_list = get_bsc_addr_list();
-
- /* Check if the given address is */
- llist_for_each_entry(addr, bsc_addr_list, list) {
- if (memcmp(&addr->calling_addr, bsc_addr, sizeof(*bsc_addr)) == 0) {
- LOGP(DMSC, LOGL_ERROR, "The calling BSC (%s) is known by this MSC, proceeding...\n",
- osmo_sccp_addr_dump(bsc_addr));
- return true;
- }
- }
+ struct msgb *msg;
+ struct bsc_context *bsc_ctx = (struct bsc_context*) priv;
- LOGP(DMSC, LOGL_ERROR, "The calling BSC (%s) is unknown to this MSC, rejecting...\n",
- osmo_sccp_addr_dump(bsc_addr));
- return false;
+ /* Skip if the A interface is not properly initalized yet */
+ if (!gsm_network)
+ return;
+
+ /* Clear all now orphaned subscriber connections */
+ a_clear_all(bsc_ctx->sccp_user, &bsc_ctx->bsc_addr);
+
+ /* Send reset to the remote BSC */
+ LOGP(DMSC, LOGL_NOTICE, "Sending RESET to BSC %s\n", osmo_sccp_addr_dump(&bsc_ctx->bsc_addr));
+ msg = gsm0808_create_reset();
+ osmo_sccp_tx_unitdata_msg(bsc_ctx->sccp_user, &bsc_ctx->msc_addr,
+ &bsc_ctx->bsc_addr, msg);
+}
+
+/* Add a new BSC connection to our internal list with known BSCs */
+static void add_bsc(struct osmo_sccp_addr *msc_addr, struct osmo_sccp_addr *bsc_addr, struct osmo_sccp_user *scu)
+{
+ struct bsc_context *bsc_ctx;
+
+ OSMO_ASSERT(bsc_addr);
+ OSMO_ASSERT(msc_addr);
+ OSMO_ASSERT(scu);
+
+ /* Check if we already know this BSC, if yes, skip adding it. */
+ if (get_reset_ctx_by_sccp_addr(bsc_addr))
+ return;
+
+ LOGP(DMSC, LOGL_NOTICE, "Adding new BSC connection for BSC %s...\n", osmo_sccp_addr_dump(bsc_addr));
+
+ /* Generate and fill up a new bsc context */
+ bsc_ctx = talloc_zero(gsm_network, struct bsc_context);
+ OSMO_ASSERT(bsc_ctx);
+ memcpy(&bsc_ctx->bsc_addr, bsc_addr, sizeof(*bsc_addr));
+ memcpy(&bsc_ctx->msc_addr, msc_addr, sizeof(*msc_addr));
+ bsc_ctx->sccp_user = scu;
+ llist_add_tail(&bsc_ctx->list, &gsm_network->a.bscs);
+
+ /* Start reset procedure to make the new connection active */
+ bsc_ctx->reset = a_reset_alloc(bsc_ctx, osmo_sccp_addr_dump(bsc_addr), a_reset_cb, bsc_ctx);
}
/* Callback function, called by the SSCP stack when data arrives */
@@ -332,15 +451,18 @@ static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
struct a_conn_info a_conn_info;
memset(&a_conn_info, 0, sizeof(a_conn_info));
a_conn_info.network = gsm_network;
+ a_conn_info.reset = NULL;
switch (OSMO_PRIM_HDR(&scu_prim->oph)) {
case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
/* Handle inbound connection indication */
+ add_bsc(&scu_prim->u.connect.called_addr, &scu_prim->u.connect.calling_addr, scu);
a_conn_info.conn_id = scu_prim->u.connect.conn_id;
a_conn_info.called_addr = &scu_prim->u.connect.called_addr;
a_conn_info.calling_addr = &scu_prim->u.connect.calling_addr;
+ a_conn_info.reset = get_reset_ctx_by_sccp_addr(&scu_prim->u.unitdata.calling_addr);
- if (test_bsc_known(a_conn_info.calling_addr) == false) {
+ if (a_reset_conn_ready(a_conn_info.reset) == false) {
rc = osmo_sccp_tx_disconn(scu, a_conn_info.conn_id, a_conn_info.called_addr,
SCCP_RETURN_CAUSE_UNQUALIFIED);
break;
@@ -353,6 +475,9 @@ static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
rc = sccp_rx_dt(scu, &a_conn_info, oph->msg);
} else
LOGP(DMSC, LOGL_DEBUG, "N-CONNECT.ind(%u)\n", scu_prim->u.connect.conn_id);
+
+ record_bsc_con(scu, &scu_prim->u.connect.calling_addr, &scu_prim->u.connect.called_addr,
+ scu_prim->u.connect.conn_id);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
@@ -365,8 +490,10 @@ static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
/* Handle inbound UNITDATA */
+ add_bsc(&scu_prim->u.unitdata.called_addr, &scu_prim->u.unitdata.calling_addr, scu);
a_conn_info.called_addr = &scu_prim->u.unitdata.called_addr;
a_conn_info.calling_addr = &scu_prim->u.unitdata.calling_addr;
+ a_conn_info.reset = get_reset_ctx_by_sccp_addr(&scu_prim->u.unitdata.calling_addr);
DEBUGP(DMSC, "N-UNITDATA.ind(%s)\n", osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
sccp_rx_udt(scu, &a_conn_info, oph->msg);
break;
@@ -379,13 +506,46 @@ static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
return rc;
}
+/* Clear all subscriber connections on a specified BSC */
+void a_clear_all(struct osmo_sccp_user *scu, struct osmo_sccp_addr *bsc_addr)
+{
+ struct gsm_subscriber_connection *conn;
+ struct gsm_subscriber_connection *conn_temp;
+ struct gsm_network *network = gsm_network;
+
+ llist_for_each_entry_safe(conn, conn_temp, &network->subscr_conns, entry) {
+ /* Clear only A connections and connections that actually
+ * belong to the specified BSC */
+ if (conn->via_ran == RAN_GERAN_A && memcmp(bsc_addr, &conn->a.bsc_addr, sizeof(conn->a.bsc_addr)) == 0) {
+ LOGP(DMSC, LOGL_NOTICE, "Dropping orphaned subscriber connection (conn_id %i)\n",
+ conn->a.conn_id);
+ msc_clear_request(conn, GSM48_CC_CAUSE_SWITCH_CONG);
+
+ /* If there is still an SCCP connection active, remove it now */
+ if (check_connection_active(conn->a.conn_id)) {
+ osmo_sccp_tx_disconn(scu, conn->a.conn_id, bsc_addr,
+ SCCP_RELEASE_CAUSE_END_USER_ORIGINATED);
+ a_delete_bsc_con(conn->a.conn_id);
+ }
+ }
+ }
+}
+
/* Initalize A interface connection between to MSC and BSC */
int a_init(void *ctx, struct osmo_sccp_instance *sccp, struct gsm_network *network)
{
+ OSMO_ASSERT(sccp);
+ OSMO_ASSERT(network);
+
/* FIXME: Remove hardcoded parameters, use parameters in parameter list */
LOGP(DMSC, LOGL_NOTICE, "Initalizing SCCP connection to stp...\n");
- gsm_network = network;
+ /* Set GSM network variable, there can only be
+ * one network by design */
+ if (gsm_network != NULL) {
+ OSMO_ASSERT(gsm_network == network);
+ } else
+ gsm_network = network;
/* SCCP Protocol stack */
osmo_sccp_user_bind(sccp, "OsmoMSC-A", sccp_sap_up, SCCP_SSN_BSSAP);