From d6ec7a4ab5e307152a94f513a3f218cda5ef8482 Mon Sep 17 00:00:00 2001 From: Philipp Maier Date: Fri, 30 Jun 2017 13:28:03 +0200 Subject: osmo-msc: finish msc-sided reset finish the implementation for msc sided reset, automatically register connecting BSCs. Ensure that all sccp connections are cleared when the reset procedure executes. --- openbsc/src/libmsc/a_iface.c | 214 ++++++++++++++++++++++++++++++++----- openbsc/src/libmsc/a_iface_bssap.c | 89 +++++++-------- 2 files changed, 223 insertions(+), 80 deletions(-) (limited to 'openbsc/src/libmsc') 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 #include #include +#include +#include /* 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); diff --git a/openbsc/src/libmsc/a_iface_bssap.c b/openbsc/src/libmsc/a_iface_bssap.c index cdddac7e7..d00ad3f31 100644 --- a/openbsc/src/libmsc/a_iface_bssap.c +++ b/openbsc/src/libmsc/a_iface_bssap.c @@ -28,34 +28,35 @@ #include #include #include +#include #include #include #include +#include #define IP_V4_ADDR_LEN 4 -/* Addresses of all BSCs which have been registered to this MSC */ -static LLIST_HEAD(bsc_addr_list); - /* * Helper functions to lookup and allocate subscribers */ /* Allocate a new subscriber connection */ static struct gsm_subscriber_connection *subscr_conn_allocate_a(struct a_conn_info *a_conn_info, - struct gsm_network *network, + struct gsm_network *network, struct ue_conn_ctx *ue, uint16_t lac, struct osmo_sccp_user *scu, int conn_id) { struct gsm_subscriber_connection *conn; - LOGP(DMSC, LOGL_NOTICE, "Allocating A-Interface subscriber conn: lac %i, conn_id %i\n", lac, conn_id); + LOGP(DMSC, LOGL_NOTICE, "Allocating A-Interface subscriber conn: lac %i, conn_id %i\n", lac, ue->conn_id); - conn = talloc_zero(network, struct gsm_subscriber_connection); + conn = talloc_zero(ue, struct gsm_subscriber_connection); if (!conn) return NULL; conn->network = network; conn->via_ran = RAN_GERAN_A; + conn->iu.ue_ctx = ue; + conn->iu.ue_ctx->rab_assign_addr_enc = network->iu.rab_assign_addr_enc; conn->lac = lac; conn->a.conn_id = conn_id; @@ -92,22 +93,6 @@ struct gsm_subscriber_connection *subscr_conn_lookup_a(struct gsm_network *netwo return NULL; } -/* Clear oprphand subscriber connections (called by bssmap_rx_reset()) */ -static void subscr_conn_clear_all(struct a_conn_info *a_conn_info) -{ - struct gsm_subscriber_connection *conn; - struct gsm_subscriber_connection *conn_temp; - struct gsm_network *network = a_conn_info->network; - - llist_for_each_entry_safe(conn, conn_temp, &network->subscr_conns, entry) { - if (conn->via_ran == RAN_GERAN_A - && memcmp(a_conn_info->calling_addr, &conn->a.bsc_addr, sizeof(conn->a.bsc_addr)) == 0) { - LOGP(DMSC, LOGL_NOTICE, "Dropping old subscriber connection (conn_id %i)\n", conn->a.conn_id); - msc_clear_request(conn, GSM48_CC_CAUSE_SWITCH_CONG); - } - } -} - /* * BSSMAP handling for UNITDATA */ @@ -115,36 +100,32 @@ static void subscr_conn_clear_all(struct a_conn_info *a_conn_info) /* Endpoint to handle BSSMAP reset */ static void bssmap_rx_reset(struct osmo_sccp_user *scu, struct a_conn_info *a_conn_info, struct msgb *msg) { - struct a_bsc_addr *addr; - struct a_bsc_addr *known_addr; - bool addr_unknown = true; - - LOGP(DMSC, LOGL_NOTICE, "Rx RESET from BSC %s\n", osmo_sccp_addr_dump(a_conn_info->calling_addr)); + LOGP(DMSC, LOGL_NOTICE, "Rx RESET from BSC %s, sending RESET ACK\n", osmo_sccp_addr_dump(a_conn_info->calling_addr)); osmo_sccp_tx_unitdata_msg(scu, a_conn_info->called_addr, a_conn_info->calling_addr, gsm0808_create_reset_ack()); /* Make sure all orphand subscriber connections will be cleard */ - subscr_conn_clear_all(a_conn_info); - - /* Check if we know this BSC already, if yes, refresh its item */ - llist_for_each_entry(known_addr, &bsc_addr_list, list) { - if (memcmp(&known_addr->calling_addr, a_conn_info->calling_addr, sizeof(*a_conn_info->calling_addr)) == - 0) { - LOGP(DMSC, LOGL_NOTICE, "This BSC is already known to this MSC, refreshing its list item\n"); - llist_del(&known_addr->list); - talloc_free(known_addr); - addr_unknown = false; - break; - } + a_clear_all(scu, a_conn_info->calling_addr); + + msgb_free(msg); +} + +/* Endpoint to handle BSSMAP reset acknowlegement */ +static void bssmap_rx_reset_ack(struct osmo_sccp_user *scu, struct a_conn_info *a_conn_info, struct msgb *msg) +{ + if (a_conn_info->reset == NULL) { + LOGP(DMSC, LOGL_ERROR, "Received RESET ACK from an unknown BSC %s, ignoring...\n", + osmo_sccp_addr_dump(a_conn_info->calling_addr)); + goto fail; } - if (addr_unknown) - LOGP(DMSC, LOGL_NOTICE, "This BSC is not known to this MSC yet, adding it to list\n"); - addr = talloc_zero(NULL, struct a_bsc_addr); - memcpy(&addr->calling_addr, a_conn_info->calling_addr, sizeof(addr->calling_addr)); - memcpy(&addr->called_addr, a_conn_info->called_addr, sizeof(addr->called_addr)); - addr->scu = scu; - llist_add(&addr->list, &bsc_addr_list); + LOGP(DMSC, LOGL_NOTICE, "Received RESET ACK from BSC %s\n", + osmo_sccp_addr_dump(a_conn_info->calling_addr)); + + /* Confirm that we managed to get the reset ack message + * towards the connection reset logic */ + a_reset_ack_confirm(a_conn_info->reset); +fail: msgb_free(msg); } @@ -165,6 +146,9 @@ static void bssmap_rcvmsg_udt(struct osmo_sccp_user *scu, struct a_conn_info *a_ case BSS_MAP_MSG_RESET: bssmap_rx_reset(scu, a_conn_info, msg); break; + case BSS_MAP_MSG_RESET_ACKNOWLEDGE: + bssmap_rx_reset_ack(scu, a_conn_info, msg); + break; default: LOGP(DMSC, LOGL_NOTICE, "Unimplemented message format: %s -- message discarded!\n", gsm0808_bssmap_name(msg->l3h[0])); @@ -256,6 +240,9 @@ static int bssmap_rx_clear_complete(struct osmo_sccp_user *scu, struct a_conn_in rc = osmo_sccp_tx_disconn(scu, a_conn_info->conn_id, a_conn_info->called_addr, SCCP_RELEASE_CAUSE_END_USER_ORIGINATED); + /* Remove the record from the list with active connections. */ + a_delete_bsc_con(a_conn_info->conn_id); + msgb_free(msg); return rc; } @@ -277,6 +264,7 @@ static int bssmap_rx_l3_compl(struct osmo_sccp_user *scu, struct a_conn_info *a_ int rc; struct gsm_network *network = a_conn_info->network; + struct ue_conn_ctx *ue; struct gsm_subscriber_connection *conn; LOGP(DMSC, LOGL_NOTICE, "BSC has completed layer 3 connection (conn_id=%i)\n", a_conn_info->conn_id); @@ -320,7 +308,8 @@ static int bssmap_rx_l3_compl(struct osmo_sccp_user *scu, struct a_conn_info *a_ msg->tail = msg->l3h + TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION); /* Create new subscriber context */ - conn = subscr_conn_allocate_a(a_conn_info, network, lac, scu, a_conn_info->conn_id); + ue = ue_conn_ctx_alloc(a_conn_info->calling_addr, a_conn_info->conn_id); + conn = subscr_conn_allocate_a(a_conn_info, network, ue, lac, scu, a_conn_info->conn_id); /* Handover location update to the MSC code */ /* msc_compl_l3() takes ownership of dtap_msg @@ -701,9 +690,3 @@ int sccp_rx_dt(struct osmo_sccp_user *scu, struct a_conn_info *a_conn_info, stru return -EINVAL; } - -/* Get a list with all known BSCs */ -struct llist_head *get_bsc_addr_list(void) -{ - return &bsc_addr_list; -} -- cgit v1.2.3