| /** |
| * This file contains helper routines for MGCP Gateway handling. |
| * |
| * The first thing to remember is that each BSC has its own namespace/range |
| * of endpoints. Whenever a BSSMAP ASSIGNMENT REQUEST is received this code |
| * will be called to select an endpoint on the BSC. The mapping from original |
| * multiplex/timeslot to BSC multiplex'/timeslot' will be stored. |
| * |
| * The second part is to take messages on the public MGCP GW interface |
| * and forward them to the right BSC. This requires the MSC to first |
| * assign the timeslot. This assumption has been true so far. We are using |
| * the policy_cb of the MGCP protocol code to decide if the request should |
| * be immediately answered or delayed. An extension "Z: noanswer" is used |
| * to request the BSC to not respond. This is saving some bytes of bandwidth |
| * and as we are using TCP to forward the message we know it will arrive. |
| * The mgcp_do_read method reads these messages and hands them to the protocol |
| * parsing code which will call the mentioned policy_cb. The bsc_mgcp_forward |
| * method is used on the way back from the BSC to the network. |
| * |
| * The third part is to patch messages forwarded to the BSC. This includes |
| * the endpoint number, the ports to be used inside the SDP file and maybe |
| * some other bits. |
| * |
| */ |
| /* |
| * (C) 2010-2012 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * (C) 2010-2012 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 <openbsc/bsc_nat_callstats.h> |
| #include <openbsc/bsc_nat_sccp.h> |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/ipaccess.h> |
| #include <openbsc/mgcp.h> |
| #include <openbsc/mgcp_internal.h> |
| #include <openbsc/osmux.h> |
| |
| #include <osmocom/ctrl/control_cmd.h> |
| |
| #include <osmocom/sccp/sccp.h> |
| |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/gsm/gsm0808.h> |
| #include <osmocom/gsm/protocol/gsm_08_08.h> |
| |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| |
| #include <errno.h> |
| #include <unistd.h> |
| |
| static void send_direct(struct bsc_nat *nat, struct msgb *output) |
| { |
| if (osmo_wqueue_enqueue(&nat->mgcp_cfg->gw_fd, output) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to queue MGCP msg.\n"); |
| msgb_free(output); |
| } |
| } |
| |
| static void mgcp_queue_for_call_agent(struct bsc_nat *nat, struct msgb *output) |
| { |
| if (nat->mgcp_ipa) |
| bsc_nat_send_mgcp_to_msc(nat, output); |
| else |
| send_direct(nat, output); |
| } |
| |
| int bsc_mgcp_nr_multiplexes(int max_endpoints) |
| { |
| int div = max_endpoints / 32; |
| |
| if ((max_endpoints % 32) != 0) |
| div += 1; |
| |
| return div; |
| } |
| |
| static int bsc_init_endps_if_needed(struct bsc_connection *con) |
| { |
| int multiplexes; |
| |
| /* we have done that */ |
| if (con->_endpoint_status) |
| return 0; |
| |
| /* we have no config... */ |
| if (!con->cfg) |
| return -1; |
| |
| multiplexes = bsc_mgcp_nr_multiplexes(con->cfg->max_endpoints); |
| con->number_multiplexes = multiplexes; |
| con->max_endpoints = con->cfg->max_endpoints; |
| con->_endpoint_status = talloc_zero_array(con, char, 32 * multiplexes + 1); |
| return con->_endpoint_status == NULL; |
| } |
| |
| static int bsc_assign_endpoint(struct bsc_connection *bsc, struct nat_sccp_connection *con) |
| { |
| int multiplex; |
| int timeslot; |
| const int number_endpoints = bsc->max_endpoints; |
| int i; |
| |
| mgcp_endpoint_to_timeslot(bsc->last_endpoint, &multiplex, ×lot); |
| timeslot += 1; |
| |
| for (i = 0; i < number_endpoints; ++i) { |
| int endpoint; |
| |
| /* Wrap around timeslots */ |
| if (timeslot == 0) |
| timeslot = 1; |
| |
| if (timeslot == 0x1f) { |
| timeslot = 1; |
| multiplex += 1; |
| } |
| |
| /* Wrap around the multiplex */ |
| if (multiplex >= bsc->number_multiplexes) |
| multiplex = 0; |
| |
| endpoint = mgcp_timeslot_to_endpoint(multiplex, timeslot); |
| |
| /* Now check if we are allowed to assign this one */ |
| if (endpoint >= bsc->max_endpoints) { |
| multiplex = 0; |
| timeslot = 1; |
| endpoint = mgcp_timeslot_to_endpoint(multiplex, timeslot); |
| } |
| |
| |
| if (bsc->_endpoint_status[endpoint] == 0) { |
| bsc->_endpoint_status[endpoint] = 1; |
| con->bsc_endp = endpoint; |
| bsc->last_endpoint = endpoint; |
| return 0; |
| } |
| |
| timeslot += 1; |
| } |
| |
| return -1; |
| } |
| |
| static uint16_t create_cic(int endpoint) |
| { |
| int timeslot, multiplex; |
| |
| mgcp_endpoint_to_timeslot(endpoint, &multiplex, ×lot); |
| return (multiplex << 5) | (timeslot & 0x1f); |
| } |
| |
| int bsc_mgcp_assign_patch(struct nat_sccp_connection *con, struct msgb *msg) |
| { |
| struct nat_sccp_connection *mcon; |
| struct tlv_parsed tp; |
| uint16_t cic; |
| uint8_t timeslot; |
| uint8_t multiplex; |
| unsigned int endp; |
| |
| if (!msg->l3h) { |
| LOGP(DNAT, LOGL_ERROR, "Assignment message should have l3h pointer.\n"); |
| return -1; |
| } |
| |
| if (msgb_l3len(msg) < 3) { |
| LOGP(DNAT, LOGL_ERROR, "Assignment message has not enough space for GSM0808.\n"); |
| return -1; |
| } |
| |
| tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0); |
| if (!TLVP_PRESENT(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)) { |
| LOGP(DNAT, LOGL_ERROR, "Circuit identity code not found in assignment message.\n"); |
| return -1; |
| } |
| |
| cic = ntohs(tlvp_val16_unal(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)); |
| timeslot = cic & 0x1f; |
| multiplex = (cic & ~0x1f) >> 5; |
| |
| |
| endp = mgcp_timeslot_to_endpoint(multiplex, timeslot); |
| |
| if (endp >= con->bsc->nat->mgcp_cfg->trunk.number_endpoints) { |
| LOGP(DNAT, LOGL_ERROR, |
| "MSC attempted to assign bad endpoint 0x%x\n", |
| endp); |
| return -1; |
| } |
| |
| /* find stale connections using that endpoint */ |
| llist_for_each_entry(mcon, &con->bsc->nat->sccp_connections, list_entry) { |
| if (mcon->msc_endp == endp) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Endpoint %d was assigned to 0x%x and now 0x%x\n", |
| endp, |
| sccp_src_ref_to_int(&mcon->patched_ref), |
| sccp_src_ref_to_int(&con->patched_ref)); |
| bsc_mgcp_dlcx(mcon); |
| } |
| } |
| |
| con->msc_endp = endp; |
| if (bsc_init_endps_if_needed(con->bsc) != 0) |
| return -1; |
| if (bsc_assign_endpoint(con->bsc, con) != 0) |
| return -1; |
| |
| /* |
| * now patch the message for the new CIC... |
| * still assumed to be one multiplex only |
| */ |
| cic = htons(create_cic(con->bsc_endp)); |
| memcpy((uint8_t *) TLVP_VAL(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE), |
| &cic, sizeof(cic)); |
| |
| return 0; |
| } |
| |
| static void bsc_mgcp_free_endpoint(struct bsc_nat *nat, int i) |
| { |
| if (nat->bsc_endpoints[i].transaction_id) { |
| talloc_free(nat->bsc_endpoints[i].transaction_id); |
| nat->bsc_endpoints[i].transaction_id = NULL; |
| } |
| |
| nat->bsc_endpoints[i].transaction_state = 0; |
| nat->bsc_endpoints[i].bsc = NULL; |
| } |
| |
| void bsc_mgcp_free_endpoints(struct bsc_nat *nat) |
| { |
| int i; |
| |
| for (i = 1; i < nat->mgcp_cfg->trunk.number_endpoints; ++i){ |
| bsc_mgcp_free_endpoint(nat, i); |
| mgcp_release_endp(&nat->mgcp_cfg->trunk.endpoints[i]); |
| } |
| } |
| |
| /* send a MDCX where we do not want a response */ |
| static void bsc_mgcp_send_mdcx(struct bsc_connection *bsc, int port, struct mgcp_endpoint *endp) |
| { |
| char buf[2096]; |
| int len; |
| |
| len = snprintf(buf, sizeof(buf), |
| "MDCX 23 %x@mgw MGCP 1.0\r\n" |
| "Z: noanswer\r\n" |
| "\r\n" |
| "c=IN IP4 %s\r\n" |
| "m=audio %d RTP/AVP 255\r\n", |
| port, bsc->nat->mgcp_cfg->source_addr, |
| endp->bts_end.local_port); |
| if (len < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "snprintf for MDCX failed.\n"); |
| return; |
| } |
| |
| bsc_write_mgcp(bsc, (uint8_t *) buf, len); |
| } |
| |
| static void bsc_mgcp_send_dlcx(struct bsc_connection *bsc, int endpoint, int trans) |
| { |
| char buf[2096]; |
| int len; |
| |
| /* |
| * The following is a bit of a spec violation. According to the |
| * MGCP grammar the transaction id is are upto 9 digits but we |
| * prefix it with an alpha numeric value so we can easily recognize |
| * it as a response. |
| */ |
| len = snprintf(buf, sizeof(buf), |
| "DLCX nat-%u %x@mgw MGCP 1.0\r\n", |
| trans, endpoint); |
| if (len < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "snprintf for DLCX failed.\n"); |
| return; |
| } |
| |
| bsc_write_mgcp(bsc, (uint8_t *) buf, len); |
| } |
| |
| void bsc_mgcp_init(struct nat_sccp_connection *con) |
| { |
| con->msc_endp = -1; |
| con->bsc_endp = -1; |
| } |
| |
| /** |
| * This code will remember the network side of the audio statistics and |
| * once the internal DLCX response arrives this can be combined with the |
| * the BSC side and forwarded as a trap. |
| */ |
| static void remember_pending_dlcx(struct nat_sccp_connection *con, uint32_t transaction) |
| { |
| struct bsc_nat_call_stats *stats; |
| struct bsc_connection *bsc = con->bsc; |
| struct mgcp_endpoint *endp; |
| |
| stats = talloc_zero(bsc, struct bsc_nat_call_stats); |
| if (!stats) { |
| LOGP(DNAT, LOGL_NOTICE, |
| "Failed to allocate statistics for endpoint 0x%x\n", |
| con->msc_endp); |
| return; |
| } |
| |
| /* take the endpoint here */ |
| endp = &bsc->nat->mgcp_cfg->trunk.endpoints[con->msc_endp]; |
| |
| stats->remote_ref = con->remote_ref; |
| stats->src_ref = con->patched_ref; |
| |
| stats->ci = endp->ci; |
| stats->bts_rtp_port = endp->bts_end.rtp_port; |
| stats->bts_addr = endp->bts_end.addr; |
| stats->net_rtp_port = endp->net_end.rtp_port; |
| stats->net_addr = endp->net_end.addr; |
| |
| stats->net_ps = endp->net_end.packets; |
| stats->net_os = endp->net_end.octets; |
| stats->bts_pr = endp->bts_end.packets; |
| stats->bts_or = endp->bts_end.octets; |
| mgcp_state_calc_loss(&endp->bts_state, &endp->bts_end, |
| &stats->bts_expected, &stats->bts_loss); |
| stats->bts_jitter = mgcp_state_calc_jitter(&endp->bts_state); |
| |
| stats->trans_id = transaction; |
| stats->msc_endpoint = con->msc_endp; |
| |
| /* |
| * Too many pending requests.. let's remove the first two items. |
| */ |
| if (!llist_empty(&bsc->pending_dlcx) && |
| bsc->pending_dlcx_count >= bsc->cfg->max_endpoints * 3) { |
| struct bsc_nat_call_stats *tmp; |
| LOGP(DNAT, LOGL_ERROR, |
| "Too many(%d) pending DLCX responses on BSC: %d\n", |
| bsc->pending_dlcx_count, bsc->cfg->nr); |
| bsc->pending_dlcx_count -= 1; |
| tmp = (struct bsc_nat_call_stats *) bsc->pending_dlcx.next; |
| llist_del(&tmp->entry); |
| talloc_free(tmp); |
| } |
| |
| bsc->pending_dlcx_count += 1; |
| llist_add_tail(&stats->entry, &bsc->pending_dlcx); |
| } |
| |
| void bsc_mgcp_dlcx(struct nat_sccp_connection *con) |
| { |
| /* send a DLCX down the stream */ |
| if (con->bsc_endp != -1 && con->bsc->_endpoint_status) { |
| LOGP(DNAT, LOGL_NOTICE, |
| "Endpoint 0x%x was allocated for bsc: %d. Freeing it.\n", |
| con->bsc_endp, con->bsc->cfg->nr); |
| if (con->bsc->_endpoint_status[con->bsc_endp] != 1) |
| LOGP(DNAT, LOGL_ERROR, "Endpoint 0x%x was not in use\n", con->bsc_endp); |
| remember_pending_dlcx(con, con->bsc->next_transaction); |
| con->bsc->_endpoint_status[con->bsc_endp] = 0; |
| bsc_mgcp_send_dlcx(con->bsc, con->bsc_endp, con->bsc->next_transaction++); |
| bsc_mgcp_free_endpoint(con->bsc->nat, con->msc_endp); |
| } |
| |
| bsc_mgcp_init(con); |
| |
| } |
| |
| /* |
| * Search for the pending request |
| */ |
| static void handle_dlcx_response(struct bsc_connection *bsc, struct msgb *msg, |
| int code, const char *transaction) |
| { |
| uint32_t trans_id = UINT32_MAX; |
| uint32_t b_ps, b_os, n_pr, n_or, jitter; |
| int loss; |
| struct bsc_nat_call_stats *tmp, *stat = NULL; |
| struct ctrl_cmd *cmd; |
| |
| /* parse the transaction identifier */ |
| int rc = sscanf(transaction, "nat-%u", &trans_id); |
| if (rc != 1) { |
| LOGP(DNAT, LOGL_ERROR, "Can not parse transaction id: '%s'\n", |
| transaction); |
| return; |
| } |
| |
| /* find the answer for the request we made */ |
| llist_for_each_entry(tmp, &bsc->pending_dlcx, entry) { |
| if (trans_id != tmp->trans_id) |
| continue; |
| |
| stat = tmp; |
| break; |
| } |
| |
| if (!stat) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Can not find transaction for: %u\n", trans_id); |
| return; |
| } |
| |
| /* attempt to parse the data now */ |
| rc = mgcp_parse_stats(msg, &b_ps, &b_os, &n_pr, &n_or, &loss, &jitter); |
| if (rc != 0) |
| LOGP(DNAT, LOGL_ERROR, |
| "Can not parse connection statistics: %d\n", rc); |
| |
| /* send a trap now */ |
| cmd = ctrl_cmd_create(bsc, CTRL_TYPE_TRAP); |
| if (!cmd) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Creating a ctrl cmd failed.\n"); |
| goto free_stat; |
| } |
| |
| cmd->id = "0"; |
| cmd->variable = talloc_asprintf(cmd, "net.0.bsc.%d.call_stats.v2", |
| bsc->cfg->nr); |
| cmd->reply = talloc_asprintf(cmd, |
| "mg_ip_addr=%s,mg_port=%d,", |
| inet_ntoa(stat->net_addr), |
| stat->net_rtp_port); |
| cmd->reply = talloc_asprintf_append(cmd->reply, |
| "endpoint_ip_addr=%s,endpoint_port=%d,", |
| inet_ntoa(stat->bts_addr), |
| stat->bts_rtp_port); |
| cmd->reply = talloc_asprintf_append(cmd->reply, |
| "nat_pkt_in=%u,nat_pkt_out=%u," |
| "nat_bytes_in=%u,nat_bytes_out=%u," |
| "nat_jitter=%u,nat_pkt_lost=%d,", |
| stat->bts_pr, stat->net_ps, |
| stat->bts_or, stat->net_os, |
| stat->bts_jitter, stat->bts_loss); |
| cmd->reply = talloc_asprintf_append(cmd->reply, |
| "bsc_pkt_in=%u,bsc_pkt_out=%u," |
| "bsc_bytes_in=%u,bsc_bytes_out=%u," |
| "bsc_jitter=%u,bsc_pkt_lost=%d,", |
| n_pr, b_ps, |
| n_or, b_os, |
| jitter, loss); |
| cmd->reply = talloc_asprintf_append(cmd->reply, |
| "sccp_src_ref=%u,sccp_dst_ref=%u", |
| sccp_src_ref_to_int(&stat->src_ref), |
| sccp_src_ref_to_int(&stat->remote_ref)); |
| |
| /* send it and be done */ |
| ctrl_cmd_send_to_all(bsc->nat->ctrl, cmd); |
| talloc_free(cmd); |
| |
| free_stat: |
| bsc->pending_dlcx_count -= 1; |
| llist_del(&stat->entry); |
| talloc_free(stat); |
| } |
| |
| |
| struct nat_sccp_connection *bsc_mgcp_find_con(struct bsc_nat *nat, int endpoint) |
| { |
| struct nat_sccp_connection *con = NULL; |
| struct nat_sccp_connection *sccp; |
| |
| llist_for_each_entry(sccp, &nat->sccp_connections, list_entry) { |
| if (sccp->msc_endp == -1) |
| continue; |
| if (sccp->msc_endp != endpoint) |
| continue; |
| |
| con = sccp; |
| } |
| |
| if (con) |
| return con; |
| |
| LOGP(DMGCP, LOGL_ERROR, |
| "Failed to find the connection for endpoint: 0x%x\n", endpoint); |
| return NULL; |
| } |
| |
| static int bsc_mgcp_policy_cb(struct mgcp_trunk_config *tcfg, int endpoint, int state, const char *transaction_id) |
| { |
| struct bsc_nat *nat; |
| struct bsc_endpoint *bsc_endp; |
| struct nat_sccp_connection *sccp; |
| struct mgcp_endpoint *mgcp_endp; |
| struct msgb *bsc_msg; |
| int osmux_cid = -1; |
| |
| nat = tcfg->cfg->data; |
| bsc_endp = &nat->bsc_endpoints[endpoint]; |
| mgcp_endp = &nat->mgcp_cfg->trunk.endpoints[endpoint]; |
| |
| if (bsc_endp->transaction_id) { |
| LOGP(DMGCP, LOGL_ERROR, "Endpoint 0x%x had pending transaction: '%s'\n", |
| endpoint, bsc_endp->transaction_id); |
| talloc_free(bsc_endp->transaction_id); |
| bsc_endp->transaction_id = NULL; |
| bsc_endp->transaction_state = 0; |
| } |
| bsc_endp->bsc = NULL; |
| |
| sccp = bsc_mgcp_find_con(nat, endpoint); |
| |
| if (!sccp) { |
| LOGP(DMGCP, LOGL_ERROR, "Did not find BSC for change on endpoint: 0x%x state: %d\n", endpoint, state); |
| |
| switch (state) { |
| case MGCP_ENDP_CRCX: |
| return MGCP_POLICY_REJECT; |
| break; |
| case MGCP_ENDP_DLCX: |
| return MGCP_POLICY_CONT; |
| break; |
| case MGCP_ENDP_MDCX: |
| return MGCP_POLICY_CONT; |
| break; |
| default: |
| LOGP(DMGCP, LOGL_FATAL, "Unhandled state: %d\n", state); |
| return MGCP_POLICY_CONT; |
| break; |
| } |
| } |
| |
| /* Allocate a Osmux circuit ID */ |
| if (state == MGCP_ENDP_CRCX && |
| nat->mgcp_cfg->osmux && sccp->bsc->cfg->osmux) |
| osmux_cid = osmux_get_cid(); |
| |
| /* we need to generate a new and patched message */ |
| bsc_msg = bsc_mgcp_rewrite((char *) nat->mgcp_msg, nat->mgcp_length, |
| sccp->bsc_endp, nat->mgcp_cfg->source_addr, |
| mgcp_endp->bts_end.local_port, osmux_cid, |
| &mgcp_endp->net_end.codec.payload_type); |
| if (!bsc_msg) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to patch the msg.\n"); |
| return MGCP_POLICY_CONT; |
| } |
| |
| |
| bsc_endp->transaction_id = talloc_strdup(nat, transaction_id); |
| bsc_endp->transaction_state = state; |
| bsc_endp->bsc = sccp->bsc; |
| |
| /* we need to update some bits */ |
| if (state == MGCP_ENDP_CRCX) { |
| struct sockaddr_in sock; |
| |
| /* Annotate the allocated Osmux CID until the bsc confirms that |
| * it agrees to use Osmux for this voice flow. |
| */ |
| if (osmux_cid >= 0 && |
| mgcp_endp->osmux.state != OSMUX_STATE_ENABLED) { |
| mgcp_endp->osmux.state = OSMUX_STATE_ACTIVATING; |
| mgcp_endp->osmux.cid = osmux_cid; |
| } |
| |
| socklen_t len = sizeof(sock); |
| if (getpeername(sccp->bsc->write_queue.bfd.fd, (struct sockaddr *) &sock, &len) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Can not get the peername...%d/%s\n", |
| errno, strerror(errno)); |
| } else { |
| mgcp_endp->bts_end.addr = sock.sin_addr; |
| } |
| |
| /* send the message and a fake MDCX to force sending of a dummy packet */ |
| bsc_write(sccp->bsc, bsc_msg, IPAC_PROTO_MGCP_OLD); |
| bsc_mgcp_send_mdcx(sccp->bsc, sccp->bsc_endp, mgcp_endp); |
| return MGCP_POLICY_DEFER; |
| } else if (state == MGCP_ENDP_DLCX) { |
| /* we will free the endpoint now and send a DLCX to the BSC */ |
| msgb_free(bsc_msg); |
| bsc_mgcp_dlcx(sccp); |
| |
| /* libmgcp clears the MGCP endpoint for us */ |
| if (mgcp_endp->osmux.state == OSMUX_STATE_ENABLED) |
| osmux_put_cid(mgcp_endp->osmux.cid); |
| |
| return MGCP_POLICY_CONT; |
| } else { |
| bsc_write(sccp->bsc, bsc_msg, IPAC_PROTO_MGCP_OLD); |
| return MGCP_POLICY_DEFER; |
| } |
| } |
| |
| /* |
| * We do have a failure, free data downstream.. |
| */ |
| static void free_chan_downstream(struct mgcp_endpoint *endp, struct bsc_endpoint *bsc_endp, |
| struct bsc_connection *bsc) |
| { |
| LOGP(DMGCP, LOGL_ERROR, "No CI, freeing endpoint 0x%x in state %d\n", |
| ENDPOINT_NUMBER(endp), bsc_endp->transaction_state); |
| |
| /* if a CRCX failed... send a DLCX down the stream */ |
| if (bsc_endp->transaction_state == MGCP_ENDP_CRCX) { |
| struct nat_sccp_connection *con; |
| con = bsc_mgcp_find_con(bsc->nat, ENDPOINT_NUMBER(endp)); |
| if (!con) { |
| LOGP(DMGCP, LOGL_ERROR, |
| "No SCCP connection for endp 0x%x\n", |
| ENDPOINT_NUMBER(endp)); |
| } else { |
| if (con->bsc == bsc) { |
| bsc_mgcp_send_dlcx(bsc, con->bsc_endp, con->bsc->next_transaction++); |
| } else { |
| LOGP(DMGCP, LOGL_ERROR, |
| "Endpoint belongs to a different BSC\n"); |
| } |
| } |
| } |
| |
| bsc_mgcp_free_endpoint(bsc->nat, ENDPOINT_NUMBER(endp)); |
| mgcp_release_endp(endp); |
| } |
| |
| static void bsc_mgcp_osmux_confirm(struct mgcp_endpoint *endp, const char *str) |
| { |
| unsigned int osmux_cid; |
| char *res; |
| |
| res = strstr(str, "X-Osmux: "); |
| if (!res) { |
| LOGP(DMGCP, LOGL_INFO, |
| "BSC doesn't want to use Osmux, failing back to RTP\n"); |
| goto err; |
| } |
| |
| if (sscanf(res, "X-Osmux: %u", &osmux_cid) != 1) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to parse Osmux CID '%s'\n", |
| str); |
| goto err; |
| } |
| |
| if (endp->osmux.cid != osmux_cid) { |
| LOGP(DMGCP, LOGL_ERROR, |
| "BSC sent us wrong CID %u, we expected %u", |
| osmux_cid, endp->osmux.cid); |
| goto err; |
| } |
| |
| LOGP(DMGCP, LOGL_NOTICE, "bsc accepted to use Osmux (cid=%u)\n", |
| osmux_cid); |
| return; |
| err: |
| osmux_put_cid(endp->osmux.cid); |
| endp->osmux.cid = -1; |
| endp->osmux.state = OSMUX_STATE_DISABLED; |
| } |
| |
| /* |
| * We have received a msg from the BSC. We will see if we know |
| * this transaction and if it belongs to the BSC. Then we will |
| * need to patch the content to point to the local network and we |
| * need to update the I: that was assigned by the BSS. |
| * |
| * Only responses to CRCX and DLCX should arrive here. The DLCX |
| * needs to be handled specially to combine the two statistics. |
| */ |
| void bsc_mgcp_forward(struct bsc_connection *bsc, struct msgb *msg) |
| { |
| struct msgb *output; |
| struct bsc_endpoint *bsc_endp = NULL; |
| struct mgcp_endpoint *endp = NULL; |
| int i, code; |
| char transaction_id[60]; |
| |
| /* Some assumption that our buffer is big enough.. and null terminate */ |
| if (msgb_l2len(msg) > 2000) { |
| LOGP(DMGCP, LOGL_ERROR, "MGCP message too long.\n"); |
| return; |
| } |
| |
| msg->l2h[msgb_l2len(msg)] = '\0'; |
| |
| if (bsc_mgcp_parse_response((const char *) msg->l2h, &code, transaction_id) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to parse response code.\n"); |
| return; |
| } |
| |
| for (i = 1; i < bsc->nat->mgcp_cfg->trunk.number_endpoints; ++i) { |
| if (bsc->nat->bsc_endpoints[i].bsc != bsc) |
| continue; |
| /* no one listening? a bug? */ |
| if (!bsc->nat->bsc_endpoints[i].transaction_id) |
| continue; |
| if (strcmp(transaction_id, bsc->nat->bsc_endpoints[i].transaction_id) != 0) |
| continue; |
| |
| endp = &bsc->nat->mgcp_cfg->trunk.endpoints[i]; |
| bsc_endp = &bsc->nat->bsc_endpoints[i]; |
| break; |
| } |
| |
| if (!bsc_endp && strncmp("nat-", transaction_id, 4) == 0) { |
| handle_dlcx_response(bsc, msg, code, transaction_id); |
| return; |
| } |
| |
| if (!bsc_endp) { |
| LOGP(DMGCP, LOGL_ERROR, "Could not find active endpoint: %s for msg: '%s'\n", |
| transaction_id, (const char *) msg->l2h); |
| return; |
| } |
| |
| endp->ci = bsc_mgcp_extract_ci((const char *) msg->l2h); |
| if (endp->ci == CI_UNUSED) { |
| free_chan_downstream(endp, bsc_endp, bsc); |
| return; |
| } |
| |
| if (endp->osmux.state == OSMUX_STATE_ACTIVATING) |
| bsc_mgcp_osmux_confirm(endp, (const char *) msg->l2h); |
| |
| /* free some stuff */ |
| talloc_free(bsc_endp->transaction_id); |
| bsc_endp->transaction_id = NULL; |
| bsc_endp->transaction_state = 0; |
| |
| /* |
| * rewrite the information. In case the endpoint was deleted |
| * there should be nothing for us to rewrite so putting endp->rtp_port |
| * with the value of 0 should be no problem. |
| */ |
| output = bsc_mgcp_rewrite((char * ) msg->l2h, msgb_l2len(msg), -1, |
| bsc->nat->mgcp_cfg->source_addr, |
| endp->net_end.local_port, -1, |
| &endp->bts_end.codec.payload_type); |
| if (!output) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to rewrite MGCP msg.\n"); |
| return; |
| } |
| |
| mgcp_queue_for_call_agent(bsc->nat, output); |
| } |
| |
| int bsc_mgcp_parse_response(const char *str, int *code, char transaction[60]) |
| { |
| int rc; |
| /* we want to parse two strings */ |
| rc = sscanf(str, "%3d %59s\n", code, transaction) != 2; |
| transaction[59] = '\0'; |
| return rc; |
| } |
| |
| uint32_t bsc_mgcp_extract_ci(const char *str) |
| { |
| unsigned int ci; |
| char *res = strstr(str, "I: "); |
| if (!res) { |
| LOGP(DMGCP, LOGL_ERROR, "No CI in msg '%s'\n", str); |
| return CI_UNUSED; |
| } |
| |
| if (sscanf(res, "I: %u", &ci) != 1) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to parse CI in msg '%s'\n", str); |
| return CI_UNUSED; |
| } |
| |
| return ci; |
| } |
| |
| /** |
| * Create a new MGCPCommand based on the input and endpoint from a message |
| */ |
| static void patch_mgcp(struct msgb *output, const char *op, const char *tok, |
| int endp, int len, int cr, int osmux_cid) |
| { |
| int slen; |
| int ret; |
| char buf[40]; |
| char osmux_extension[strlen("X-Osmux: 255")]; |
| |
| buf[0] = buf[39] = '\0'; |
| ret = sscanf(tok, "%*s %s", buf); |
| if (ret != 1) { |
| LOGP(DMGCP, LOGL_ERROR, |
| "Failed to find Endpoint in: %s\n", tok); |
| return; |
| } |
| |
| if (osmux_cid >= 0) |
| sprintf(osmux_extension, "\nX-Osmux: %u", osmux_cid); |
| else |
| osmux_extension[0] = '\0'; |
| |
| slen = sprintf((char *) output->l3h, "%s %s %x@mgw MGCP 1.0%s%s", |
| op, buf, endp, osmux_extension, cr ? "\r\n" : "\n"); |
| output->l3h = msgb_put(output, slen); |
| } |
| |
| /* we need to replace some strings... */ |
| struct msgb *bsc_mgcp_rewrite(char *input, int length, int endpoint, |
| const char *ip, int port, int osmux_cid, |
| int *payload_type) |
| { |
| static const char crcx_str[] = "CRCX "; |
| static const char dlcx_str[] = "DLCX "; |
| static const char mdcx_str[] = "MDCX "; |
| |
| static const char ip_str[] = "c=IN IP4 "; |
| static const char aud_str[] = "m=audio "; |
| static const char fmt_str[] = "a=fmtp:"; |
| |
| char buf[128]; |
| char *running, *token; |
| struct msgb *output; |
| |
| /* keep state to add the a=fmtp line */ |
| int found_fmtp = 0; |
| int payload = -1; |
| int cr = 1; |
| |
| if (length > 4096 - 256) { |
| LOGP(DMGCP, LOGL_ERROR, "Input is too long.\n"); |
| return NULL; |
| } |
| |
| output = msgb_alloc_headroom(4096, 128, "MGCP rewritten"); |
| if (!output) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to allocate new MGCP msg.\n"); |
| return NULL; |
| } |
| |
| running = input; |
| output->l2h = output->data; |
| output->l3h = output->l2h; |
| for (token = strsep(&running, "\n"); running; token = strsep(&running, "\n")) { |
| int len = strlen(token); |
| cr = len > 0 && token[len - 1] == '\r'; |
| |
| if (strncmp(crcx_str, token, (sizeof crcx_str) - 1) == 0) { |
| patch_mgcp(output, "CRCX", token, endpoint, len, cr, osmux_cid); |
| } else if (strncmp(dlcx_str, token, (sizeof dlcx_str) - 1) == 0) { |
| patch_mgcp(output, "DLCX", token, endpoint, len, cr, -1); |
| } else if (strncmp(mdcx_str, token, (sizeof mdcx_str) - 1) == 0) { |
| patch_mgcp(output, "MDCX", token, endpoint, len, cr, -1); |
| } else if (strncmp(ip_str, token, (sizeof ip_str) - 1) == 0) { |
| output->l3h = msgb_put(output, strlen(ip_str)); |
| memcpy(output->l3h, ip_str, strlen(ip_str)); |
| output->l3h = msgb_put(output, strlen(ip)); |
| memcpy(output->l3h, ip, strlen(ip)); |
| |
| if (cr) { |
| output->l3h = msgb_put(output, 2); |
| output->l3h[0] = '\r'; |
| output->l3h[1] = '\n'; |
| } else { |
| output->l3h = msgb_put(output, 1); |
| output->l3h[0] = '\n'; |
| } |
| } else if (strncmp(aud_str, token, (sizeof aud_str) - 1) == 0) { |
| if (sscanf(token, "m=audio %*d RTP/AVP %d", &payload) != 1) { |
| LOGP(DMGCP, LOGL_ERROR, "Could not parsed audio line.\n"); |
| msgb_free(output); |
| return NULL; |
| } |
| |
| snprintf(buf, sizeof(buf)-1, "m=audio %d RTP/AVP %d%s", |
| port, payload, cr ? "\r\n" : "\n"); |
| buf[sizeof(buf)-1] = '\0'; |
| |
| output->l3h = msgb_put(output, strlen(buf)); |
| memcpy(output->l3h, buf, strlen(buf)); |
| } else if (strncmp(fmt_str, token, (sizeof fmt_str) - 1) == 0) { |
| found_fmtp = 1; |
| goto copy; |
| } else { |
| copy: |
| output->l3h = msgb_put(output, len + 1); |
| memcpy(output->l3h, token, len); |
| output->l3h[len] = '\n'; |
| } |
| } |
| |
| /* |
| * the above code made sure that we have 128 bytes lefts. So we can |
| * safely append another line. |
| */ |
| if (!found_fmtp && payload != -1) { |
| snprintf(buf, sizeof(buf) - 1, "a=fmtp:%d mode-set=2%s", |
| payload, cr ? "\r\n" : "\n"); |
| buf[sizeof(buf) - 1] = '\0'; |
| output->l3h = msgb_put(output, strlen(buf)); |
| memcpy(output->l3h, buf, strlen(buf)); |
| } |
| |
| if (payload != -1 && payload_type) |
| *payload_type = payload; |
| |
| return output; |
| } |
| |
| /* |
| * This comes from the MSC and we will now parse it. The caller needs |
| * to free the msgb. |
| */ |
| void bsc_nat_handle_mgcp(struct bsc_nat *nat, struct msgb *msg) |
| { |
| struct msgb *resp; |
| |
| if (!nat->mgcp_ipa) { |
| LOGP(DMGCP, LOGL_ERROR, "MGCP message not allowed on IPA.\n"); |
| return; |
| } |
| |
| if (msgb_l2len(msg) > sizeof(nat->mgcp_msg) - 1) { |
| LOGP(DMGCP, LOGL_ERROR, "MGCP msg too big for handling.\n"); |
| return; |
| } |
| |
| memcpy(nat->mgcp_msg, msg->l2h, msgb_l2len(msg)); |
| nat->mgcp_length = msgb_l2len(msg); |
| nat->mgcp_msg[nat->mgcp_length] = '\0'; |
| |
| /* now handle the message */ |
| resp = mgcp_handle_message(nat->mgcp_cfg, msg); |
| |
| /* we do have a direct answer... e.g. AUEP */ |
| if (resp) |
| mgcp_queue_for_call_agent(nat, resp); |
| |
| return; |
| } |
| |
| static int mgcp_do_read(struct osmo_fd *fd) |
| { |
| struct bsc_nat *nat; |
| struct msgb *msg, *resp; |
| int rc; |
| |
| nat = fd->data; |
| |
| rc = read(fd->fd, nat->mgcp_msg, sizeof(nat->mgcp_msg) - 1); |
| if (rc <= 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to read errno: %d\n", errno); |
| return -1; |
| } |
| |
| nat->mgcp_msg[rc] = '\0'; |
| nat->mgcp_length = rc; |
| |
| msg = msgb_alloc(sizeof(nat->mgcp_msg), "MGCP GW Read"); |
| if (!msg) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to create buffer.\n"); |
| return -1; |
| } |
| |
| msg->l2h = msgb_put(msg, rc); |
| memcpy(msg->l2h, nat->mgcp_msg, msgb_l2len(msg)); |
| resp = mgcp_handle_message(nat->mgcp_cfg, msg); |
| msgb_free(msg); |
| |
| /* we do have a direct answer... e.g. AUEP */ |
| if (resp) |
| mgcp_queue_for_call_agent(nat, resp); |
| |
| return 0; |
| } |
| |
| static int mgcp_do_write(struct osmo_fd *bfd, struct msgb *msg) |
| { |
| int rc; |
| |
| rc = write(bfd->fd, msg->data, msg->len); |
| |
| if (rc != msg->len) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to write msg to MGCP CallAgent.\n"); |
| return -1; |
| } |
| |
| return rc; |
| } |
| |
| static int init_mgcp_socket(struct bsc_nat *nat, struct mgcp_config *cfg) |
| { |
| struct sockaddr_in addr; |
| int on; |
| |
| cfg->gw_fd.bfd.fd = socket(AF_INET, SOCK_DGRAM, 0); |
| if (cfg->gw_fd.bfd.fd < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to create MGCP socket. errno: %d\n", errno); |
| return -1; |
| } |
| |
| on = 1; |
| setsockopt(cfg->gw_fd.bfd.fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); |
| |
| memset(&addr, 0, sizeof(addr)); |
| addr.sin_family = AF_INET; |
| addr.sin_port = htons(cfg->source_port); |
| inet_aton(cfg->source_addr, &addr.sin_addr); |
| |
| if (bind(cfg->gw_fd.bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to bind on %s:%d errno: %d\n", |
| cfg->source_addr, cfg->source_port, errno); |
| close(cfg->gw_fd.bfd.fd); |
| cfg->gw_fd.bfd.fd = -1; |
| return -1; |
| } |
| |
| addr.sin_port = htons(2727); |
| inet_aton(cfg->call_agent_addr, &addr.sin_addr); |
| if (connect(cfg->gw_fd.bfd.fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to connect to: '%s'. errno: %d\n", |
| cfg->call_agent_addr, errno); |
| close(cfg->gw_fd.bfd.fd); |
| cfg->gw_fd.bfd.fd = -1; |
| return -1; |
| } |
| |
| osmo_wqueue_init(&cfg->gw_fd, 10); |
| cfg->gw_fd.bfd.when = BSC_FD_READ; |
| cfg->gw_fd.bfd.data = nat; |
| cfg->gw_fd.read_cb = mgcp_do_read; |
| cfg->gw_fd.write_cb = mgcp_do_write; |
| |
| if (osmo_fd_register(&cfg->gw_fd.bfd) != 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to register MGCP fd.\n"); |
| close(cfg->gw_fd.bfd.fd); |
| cfg->gw_fd.bfd.fd = -1; |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| int bsc_mgcp_nat_init(struct bsc_nat *nat) |
| { |
| struct mgcp_config *cfg = nat->mgcp_cfg; |
| |
| if (!cfg->call_agent_addr) { |
| LOGP(DMGCP, LOGL_ERROR, "The BSC nat requires the call agent ip to be set.\n"); |
| return -1; |
| } |
| |
| if (cfg->bts_ip) { |
| LOGP(DMGCP, LOGL_ERROR, "Do not set the BTS ip for the nat.\n"); |
| return -1; |
| } |
| |
| /* initialize the MGCP socket */ |
| if (!nat->mgcp_ipa) { |
| int rc = init_mgcp_socket(nat, cfg); |
| if (rc != 0) |
| return rc; |
| } |
| |
| |
| /* some more MGCP config handling */ |
| cfg->data = nat; |
| cfg->policy_cb = bsc_mgcp_policy_cb; |
| cfg->trunk.force_realloc = 1; |
| |
| if (cfg->bts_ip) |
| talloc_free(cfg->bts_ip); |
| cfg->bts_ip = ""; |
| |
| nat->bsc_endpoints = talloc_zero_array(nat, |
| struct bsc_endpoint, |
| cfg->trunk.number_endpoints + 1); |
| if (!nat->bsc_endpoints) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to allocate nat endpoints\n"); |
| close(cfg->gw_fd.bfd.fd); |
| cfg->gw_fd.bfd.fd = -1; |
| return -1; |
| } |
| |
| if (mgcp_reset_transcoder(cfg) < 0) { |
| LOGP(DMGCP, LOGL_ERROR, "Failed to send packet to the transcoder.\n"); |
| talloc_free(nat->bsc_endpoints); |
| nat->bsc_endpoints = NULL; |
| close(cfg->gw_fd.bfd.fd); |
| cfg->gw_fd.bfd.fd = -1; |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| void bsc_mgcp_clear_endpoints_for(struct bsc_connection *bsc) |
| { |
| struct rate_ctr *ctr = NULL; |
| int i; |
| |
| if (bsc->cfg) |
| ctr = &bsc->cfg->stats.ctrg->ctr[BCFG_CTR_DROPPED_CALLS]; |
| |
| for (i = 1; i < bsc->nat->mgcp_cfg->trunk.number_endpoints; ++i) { |
| struct bsc_endpoint *bsc_endp = &bsc->nat->bsc_endpoints[i]; |
| |
| if (bsc_endp->bsc != bsc) |
| continue; |
| |
| if (ctr) |
| rate_ctr_inc(ctr); |
| |
| bsc_mgcp_free_endpoint(bsc->nat, i); |
| mgcp_release_endp(&bsc->nat->mgcp_cfg->trunk.endpoints[i]); |
| } |
| } |