diff options
Diffstat (limited to 'src/osmo-bsc/osmo_bsc_msc.c')
-rw-r--r-- | src/osmo-bsc/osmo_bsc_msc.c | 586 |
1 files changed, 586 insertions, 0 deletions
diff --git a/src/osmo-bsc/osmo_bsc_msc.c b/src/osmo-bsc/osmo_bsc_msc.c new file mode 100644 index 000000000..8d02624b4 --- /dev/null +++ b/src/osmo-bsc/osmo_bsc_msc.c @@ -0,0 +1,586 @@ +/* + * Handle the connection to the MSC. This include ping/timeout/reconnect + * (C) 2008-2009 by Harald Welte <laforge@gnumonks.org> + * (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org> + * (C) 2009-2015 by On-Waves + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <openbsc/bsc_nat.h> +#include <osmocom/ctrl/control_cmd.h> +#include <osmocom/ctrl/control_if.h> +#include <osmocom/crypt/auth.h> +#include <openbsc/debug.h> +#include <openbsc/gsm_data.h> +#include <openbsc/ipaccess.h> +#include <openbsc/bsc_msc_data.h> +#include <openbsc/signal.h> + +#include <osmocom/core/talloc.h> + +#include <osmocom/gsm/gsm0808.h> + +#include <osmocom/sccp/sccp.h> + +#include <osmocom/abis/ipa.h> + +#include <sys/socket.h> +#include <netinet/tcp.h> +#include <unistd.h> + + +static void initialize_if_needed(struct bsc_msc_connection *conn); +static void send_lacs(struct gsm_network *net, struct bsc_msc_connection *conn); +static void send_id_get_response(struct bsc_msc_data *data, int fd, struct msgb *inp); +static void send_ping(struct bsc_msc_data *data); +static void schedule_ping_pong(struct bsc_msc_data *data); + +/* + * MGCP forwarding code + */ +static int mgcp_do_read(struct osmo_fd *fd) +{ + struct bsc_msc_data *data = (struct bsc_msc_data *) fd->data; + struct msgb *mgcp; + int ret; + + mgcp = msgb_alloc_headroom(4096, 128, "mgcp_from_gw"); + if (!mgcp) { + LOGP(DMGCP, LOGL_ERROR, "Failed to allocate MGCP message.\n"); + return -1; + } + + ret = read(fd->fd, mgcp->data, 4096 - 128); + if (ret <= 0) { + LOGP(DMGCP, LOGL_ERROR, "Failed to read: %d/%s\n", errno, strerror(errno)); + msgb_free(mgcp); + return -1; + } else if (ret > 4096 - 128) { + LOGP(DMGCP, LOGL_ERROR, "Too much data: %d\n", ret); + msgb_free(mgcp); + return -1; + } + + mgcp->l2h = msgb_put(mgcp, ret); + msc_queue_write(data->msc_con, mgcp, IPAC_PROTO_MGCP_OLD); + return 0; +} + +static int mgcp_do_write(struct osmo_fd *fd, struct msgb *msg) +{ + int ret; + + LOGP(DMGCP, LOGL_DEBUG, "Sending msg to MGCP GW size: %u\n", msg->len); + + ret = write(fd->fd, msg->data, msg->len); + if (ret != msg->len) + LOGP(DMGCP, LOGL_ERROR, "Failed to forward message to MGCP GW (%s).\n", strerror(errno)); + + return ret; +} + +static void mgcp_forward(struct bsc_msc_data *data, struct msgb *msg) +{ + struct msgb *mgcp; + + if (msgb_l2len(msg) > 4096) { + LOGP(DMGCP, LOGL_ERROR, "Can not forward too big message.\n"); + return; + } + + mgcp = msgb_alloc(4096, "mgcp_to_gw"); + if (!mgcp) { + LOGP(DMGCP, LOGL_ERROR, "Failed to send message.\n"); + return; + } + + msgb_put(mgcp, msgb_l2len(msg)); + memcpy(mgcp->data, msg->l2h, mgcp->len); + if (osmo_wqueue_enqueue(&data->mgcp_agent, mgcp) != 0) { + LOGP(DMGCP, LOGL_FATAL, "Could not queue message to MGCP GW.\n"); + msgb_free(mgcp); + } +} + +static int mgcp_create_port(struct bsc_msc_data *data) +{ + int on; + struct sockaddr_in addr; + + data->mgcp_agent.bfd.fd = socket(AF_INET, SOCK_DGRAM, 0); + if (data->mgcp_agent.bfd.fd < 0) { + LOGP(DMGCP, LOGL_FATAL, "Failed to create UDP socket errno: %d\n", errno); + return -1; + } + + on = 1; + setsockopt(data->mgcp_agent.bfd.fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); + + /* try to bind the socket */ + memset(&addr, 0, sizeof(addr)); + addr.sin_family = AF_INET; + addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); + addr.sin_port = 0; + + if (bind(data->mgcp_agent.bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { + LOGP(DMGCP, LOGL_FATAL, "Failed to bind to any port.\n"); + close(data->mgcp_agent.bfd.fd); + data->mgcp_agent.bfd.fd = -1; + return -1; + } + + /* connect to the remote */ + addr.sin_port = htons(2427); + if (connect(data->mgcp_agent.bfd.fd, (struct sockaddr *) & addr, sizeof(addr)) < 0) { + LOGP(DMGCP, LOGL_FATAL, "Failed to connect to local MGCP GW. %s\n", strerror(errno)); + close(data->mgcp_agent.bfd.fd); + data->mgcp_agent.bfd.fd = -1; + return -1; + } + + osmo_wqueue_init(&data->mgcp_agent, 10); + data->mgcp_agent.bfd.when = BSC_FD_READ; + data->mgcp_agent.bfd.data = data; + data->mgcp_agent.read_cb = mgcp_do_read; + data->mgcp_agent.write_cb = mgcp_do_write; + + if (osmo_fd_register(&data->mgcp_agent.bfd) != 0) { + LOGP(DMGCP, LOGL_FATAL, "Failed to register BFD\n"); + close(data->mgcp_agent.bfd.fd); + data->mgcp_agent.bfd.fd = -1; + return -1; + } + + return 0; +} + +/* + * Send data to the network + */ +int msc_queue_write(struct bsc_msc_connection *conn, struct msgb *msg, int proto) +{ + ipa_prepend_header(msg, proto); + if (osmo_wqueue_enqueue(&conn->write_queue, msg) != 0) { + LOGP(DMSC, LOGL_FATAL, "Failed to queue IPA/%d\n", proto); + msgb_free(msg); + return -1; + } + + return 0; +} + +int msc_queue_write_with_ping(struct bsc_msc_connection *conn, + struct msgb *msg, int proto) +{ + struct bsc_msc_data *data; + uint8_t val; + + /* prepend the header */ + ipa_prepend_header(msg, proto); + if (osmo_wqueue_enqueue(&conn->write_queue, msg) != 0) { + LOGP(DMSC, LOGL_FATAL, "Failed to queue IPA/%d\n", proto); + msgb_free(msg); + return -1; + } + + /* add the ping as the other message */ + val = IPAC_MSGT_PING; + msgb_l16tv_put(msg, 1, IPAC_PROTO_IPACCESS, &val); + + data = (struct bsc_msc_data *) conn->write_queue.bfd.data; + schedule_ping_pong(data); + return 0; +} + +static int msc_alink_do_write(struct osmo_fd *fd, struct msgb *msg) +{ + int ret; + + LOGP(DMSC, LOGL_DEBUG, "Sending SCCP to MSC: %u\n", msgb_l2len(msg)); + LOGP(DLMI, LOGL_DEBUG, "MSC TX %s\n", osmo_hexdump(msg->data, msg->len)); + + ret = write(fd->fd, msg->data, msg->len); + if (ret < msg->len) + perror("MSC: Failed to send SCCP"); + + return ret; +} + +static void handle_ctrl(struct bsc_msc_data *msc, struct msgb *msg) +{ + int ret; + struct ctrl_cmd *cmd; + + cmd = ctrl_cmd_parse(msc->msc_con, msg); + if (!cmd) { + LOGP(DMSC, LOGL_ERROR, "Failed to parse control message.\n"); + cmd = talloc_zero(msc->msc_con, struct ctrl_cmd); + if (!cmd) { + LOGP(DMSC, LOGL_ERROR, "OOM!\n"); + return; + } + cmd->type = CTRL_TYPE_ERROR; + cmd->id = "err"; + cmd->reply = "Failed to parse control message."; + + ctrl_cmd_send(&msc->msc_con->write_queue, cmd); + talloc_free(cmd); + + return; + } + + ret = ctrl_cmd_handle(msc->network->ctrl, cmd, msc->network); + if (ret != CTRL_CMD_HANDLED) + ctrl_cmd_send(&msc->msc_con->write_queue, cmd); + talloc_free(cmd); +} + +static void osmo_ext_handle(struct bsc_msc_data *msc, struct msgb *msg) +{ + struct ipaccess_head *hh; + struct ipaccess_head_ext *hh_ext; + + hh = (struct ipaccess_head *) msg->data; + hh_ext = (struct ipaccess_head_ext *) hh->data; + if (msg->len < sizeof(*hh) + sizeof(*hh_ext)) { + LOGP(DMSC, LOGL_ERROR, "Packet too short for extended header.\n"); + return; + } + + msg->l2h = hh_ext->data; + if (hh_ext->proto == IPAC_PROTO_EXT_MGCP) + mgcp_forward(msc, msg); + else if (hh_ext->proto == IPAC_PROTO_EXT_LAC) + send_lacs(msc->network, msc->msc_con); + else if (hh_ext->proto == IPAC_PROTO_EXT_CTRL) + handle_ctrl(msc, msg); +} + +static int ipaccess_a_fd_cb(struct osmo_fd *bfd) +{ + struct msgb *msg = NULL; + struct ipaccess_head *hh; + struct bsc_msc_data *data = (struct bsc_msc_data *) bfd->data; + int ret; + + ret = ipa_msg_recv_buffered(bfd->fd, &msg, &data->msc_con->pending_msg); + if (ret <= 0) { + if (ret == -EAGAIN) + return 0; + if (ret == 0) { + LOGP(DMSC, LOGL_ERROR, "The connection to the MSC was lost.\n"); + bsc_msc_lost(data->msc_con); + return -1; + } + + LOGP(DMSC, LOGL_ERROR, "Failed to parse ip access message: %d\n", ret); + return -1; + } + + LOGP(DLMI, LOGL_DEBUG, "From MSC: %s proto: %d\n", osmo_hexdump(msg->data, msg->len), msg->l2h[0]); + + /* handle base message handling */ + hh = (struct ipaccess_head *) msg->data; + + /* initialize the networking. This includes sending a GSM08.08 message */ + msg->cb[0] = (unsigned long) data; + if (hh->proto == IPAC_PROTO_IPACCESS) { + ipa_ccm_rcvmsg_base(msg, bfd); + if (msg->l2h[0] == IPAC_MSGT_ID_ACK) + initialize_if_needed(data->msc_con); + else if (msg->l2h[0] == IPAC_MSGT_ID_GET) { + send_id_get_response(data, bfd->fd, msg); + } else if (msg->l2h[0] == IPAC_MSGT_PONG) { + osmo_timer_del(&data->pong_timer); + } + } else if (hh->proto == IPAC_PROTO_SCCP) { + sccp_system_incoming_ctx(msg, data->msc_con); + } else if (hh->proto == IPAC_PROTO_MGCP_OLD) { + mgcp_forward(data, msg); + } else if (hh->proto == IPAC_PROTO_OSMO) { + osmo_ext_handle(data, msg); + } + + msgb_free(msg); + return 0; +} + +static void send_ping(struct bsc_msc_data *data) +{ + struct msgb *msg; + + msg = msgb_alloc_headroom(4096, 128, "ping"); + if (!msg) { + LOGP(DMSC, LOGL_ERROR, "Failed to create PING.\n"); + return; + } + + msg->l2h = msgb_put(msg, 1); + msg->l2h[0] = IPAC_MSGT_PING; + + msc_queue_write(data->msc_con, msg, IPAC_PROTO_IPACCESS); +} + +static void schedule_ping_pong(struct bsc_msc_data *data) +{ + /* send another ping in 20 seconds */ + osmo_timer_schedule(&data->ping_timer, data->ping_timeout, 0); + + /* also start a pong timer */ + osmo_timer_schedule(&data->pong_timer, data->pong_timeout, 0); +} + +static void msc_ping_timeout_cb(void *_data) +{ + struct bsc_msc_data *data = (struct bsc_msc_data *) _data; + if (data->ping_timeout <= 0) + return; + + send_ping(data); + schedule_ping_pong(data); +} + +static void msc_pong_timeout_cb(void *_data) +{ + struct bsc_msc_data *data = (struct bsc_msc_data *) _data; + + LOGP(DMSC, LOGL_ERROR, "MSC didn't answer PING. Closing connection.\n"); + bsc_msc_lost(data->msc_con); +} + +static void msc_connection_connected(struct bsc_msc_connection *con) +{ + struct msc_signal_data sig; + struct bsc_msc_data *data; + int ret, on; + on = 1; + ret = setsockopt(con->write_queue.bfd.fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)); + if (ret != 0) + LOGP(DMSC, LOGL_ERROR, "Failed to set TCP_NODELAY: %s\n", strerror(errno)); + + data = (struct bsc_msc_data *) con->write_queue.bfd.data; + msc_ping_timeout_cb(data); + + sig.data = data; + osmo_signal_dispatch(SS_MSC, S_MSC_CONNECTED, &sig); +} + +/* + * The connection to the MSC was lost and we will need to free all + * resources and then attempt to reconnect. + */ +static void msc_connection_was_lost(struct bsc_msc_connection *msc) +{ + struct msc_signal_data sig; + struct bsc_msc_data *data; + + LOGP(DMSC, LOGL_ERROR, "Lost MSC connection. Freing stuff.\n"); + + data = (struct bsc_msc_data *) msc->write_queue.bfd.data; + osmo_timer_del(&data->ping_timer); + osmo_timer_del(&data->pong_timer); + + sig.data = data; + osmo_signal_dispatch(SS_MSC, S_MSC_LOST, &sig); + + msc->is_authenticated = 0; + bsc_msc_schedule_connect(msc); +} + +static void send_lacs(struct gsm_network *net, struct bsc_msc_connection *conn) +{ + struct ipac_ext_lac_cmd *lac; + struct gsm_bts *bts; + struct msgb *msg; + int lacs = 0; + + if (llist_empty(&net->bts_list)) { + LOGP(DMSC, LOGL_ERROR, "No BTSs configured. Not sending LACs.\n"); + return; + } + + msg = msgb_alloc_headroom(4096, 128, "LAC Command"); + if (!msg) { + LOGP(DMSC, LOGL_ERROR, "Failed to create the LAC command.\n"); + return; + } + + lac = (struct ipac_ext_lac_cmd *) msgb_put(msg, sizeof(*lac)); + lac->add_remove = 1; + + llist_for_each_entry(bts, &net->bts_list, list) { + if (lacs++ == 0) + lac->lac = htons(bts->location_area_code); + else + msgb_put_u16(msg, htons(bts->location_area_code)); + } + + lac->nr_extra_lacs = lacs - 1; + ipa_prepend_header_ext(msg, IPAC_PROTO_EXT_LAC); + msc_queue_write(conn, msg, IPAC_PROTO_OSMO); +} + +static void initialize_if_needed(struct bsc_msc_connection *conn) +{ + struct msgb *msg; + + if (!conn->is_authenticated) { + /* send a gsm 08.08 reset message from here */ + msg = gsm0808_create_reset(); + if (!msg) { + LOGP(DMSC, LOGL_ERROR, "Failed to create the reset message.\n"); + return; + } + + sccp_write(msg, &sccp_ssn_bssap, &sccp_ssn_bssap, 0, conn); + msgb_free(msg); + conn->is_authenticated = 1; + } +} + +static int answer_challenge(struct bsc_msc_data *data, struct msgb *inp, struct osmo_auth_vector *vec) +{ + int ret; + struct tlv_parsed tvp; + const uint8_t *mrand; + uint8_t mrand_len; + struct osmo_sub_auth_data auth = { + .type = OSMO_AUTH_TYPE_GSM, + .algo = OSMO_AUTH_ALG_MILENAGE, + }; + + ret = ipa_ccm_idtag_parse_off(&tvp, + inp->l2h + 1, + msgb_l2len(inp) - 1, 1); + if (ret < 0) { + LOGP(DMSC, LOGL_ERROR, "ignoring IPA response " + "message with malformed TLVs: %s\n", osmo_hexdump(inp->l2h + 1, + msgb_l2len(inp) - 1)); + return 0; + } + + mrand = TLVP_VAL(&tvp, 0x23); + mrand_len = TLVP_LEN(&tvp, 0x23); + if (mrand_len != 16) { + LOGP(DMSC, LOGL_ERROR, + "RAND is not 16 bytes. Was %d\n", + mrand_len); + return 0; + } + + /* copy the key */ + memcpy(auth.u.umts.opc, data->bsc_key, 16); + memcpy(auth.u.umts.k, data->bsc_key, 16); + memset(auth.u.umts.amf, 0, 2); + auth.u.umts.sqn = 0; + + /* generate the result */ + memset(vec, 0, sizeof(*vec)); + osmo_auth_gen_vec(vec, &auth, mrand); + return 1; +} + + +static void send_id_get_response(struct bsc_msc_data *data, int fd, struct msgb *inp) +{ + struct msc_signal_data sig; + struct msgb *msg; + struct osmo_auth_vector vec; + int valid = 0; + + if (data->bsc_key_present) + valid = answer_challenge(data, inp, &vec); + + msg = bsc_msc_id_get_resp(valid, data->bsc_token, + vec.res, valid ? vec.res_len : 0); + if (!msg) + return; + msc_queue_write(data->msc_con, msg, IPAC_PROTO_IPACCESS); + + sig.data = data; + osmo_signal_dispatch(SS_MSC, S_MSC_AUTHENTICATED, &sig); +} + +int osmo_bsc_msc_init(struct bsc_msc_data *data) +{ + if (mgcp_create_port(data) != 0) + return -1; + + data->msc_con = bsc_msc_create(data, &data->dests); + if (!data->msc_con) { + LOGP(DMSC, LOGL_ERROR, "Creating the MSC network connection failed.\n"); + return -1; + } + + osmo_timer_setup(&data->ping_timer, msc_ping_timeout_cb, data); + osmo_timer_setup(&data->pong_timer, msc_pong_timeout_cb, data); + + data->msc_con->write_queue.bfd.data = data; + data->msc_con->connection_loss = msc_connection_was_lost; + data->msc_con->connected = msc_connection_connected; + data->msc_con->write_queue.read_cb = ipaccess_a_fd_cb; + data->msc_con->write_queue.write_cb = msc_alink_do_write; + bsc_msc_connect(data->msc_con); + + return 0; +} + +struct bsc_msc_data *osmo_msc_data_find(struct gsm_network *net, int nr) +{ + struct bsc_msc_data *msc_data; + + llist_for_each_entry(msc_data, &net->bsc_data->mscs, entry) + if (msc_data->nr == nr) + return msc_data; + return NULL; +} + +struct bsc_msc_data *osmo_msc_data_alloc(struct gsm_network *net, int nr) +{ + struct bsc_msc_data *msc_data; + + /* check if there is already one */ + msc_data = osmo_msc_data_find(net, nr); + if (msc_data) + return msc_data; + + msc_data = talloc_zero(net, struct bsc_msc_data); + if (!msc_data) + return NULL; + + llist_add_tail(&msc_data->entry, &net->bsc_data->mscs); + + /* Init back pointer */ + msc_data->network = net; + + INIT_LLIST_HEAD(&msc_data->dests); + msc_data->ping_timeout = 20; + msc_data->pong_timeout = 5; + msc_data->core_mnc = -1; + msc_data->core_mcc = -1; + msc_data->core_ci = -1; + msc_data->core_lac = -1; + msc_data->rtp_base = 4000; + + msc_data->nr = nr; + msc_data->allow_emerg = 1; + + /* Defaults for the audio setup */ + msc_data->amr_conf.m5_90 = 1; + + return msc_data; +} |