/** * 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 * (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 . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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, mgcp_bts_src_addr(endp), 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 nat_osmux_only(struct mgcp_config *mgcp_cfg, struct bsc_config *bsc_cfg) { if (mgcp_cfg->osmux == OSMUX_USAGE_ONLY) return 1; if (bsc_cfg->osmux == OSMUX_USAGE_ONLY) return 1; return 0; } 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; 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) { if (nat->mgcp_cfg->osmux && sccp->bsc->cfg->osmux) { osmux_allocate_cid(mgcp_endp); if (mgcp_endp->osmux.allocated_cid < 0 && nat_osmux_only(nat->mgcp_cfg, sccp->bsc->cfg)) { LOGP(DMGCP, LOGL_ERROR, "Rejecting usage of endpoint\n"); return MGCP_POLICY_REJECT; } } } /* we need to generate a new and patched message */ bsc_msg = bsc_mgcp_rewrite((char *) nat->mgcp_msg, nat->mgcp_length, sccp->bsc_endp, mgcp_bts_src_addr(mgcp_endp), mgcp_endp->bts_end.local_port, mgcp_endp->osmux.allocated_cid, &mgcp_endp->net_end.codec.payload_type, nat->sdp_ensure_amr_mode_set); 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 (mgcp_endp->osmux.allocated_cid >= 0 && mgcp_endp->osmux.state != OSMUX_STATE_ENABLED) { mgcp_endp->osmux.state = OSMUX_STATE_NEGOTIATING; mgcp_endp->osmux.cid = mgcp_endp->osmux.allocated_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_release_cid(mgcp_endp); 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); endp->osmux.state = OSMUX_STATE_ACTIVATING; return; err: osmux_release_cid(endp); 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_NEGOTIATING) bsc_mgcp_osmux_confirm(endp, (const char *) msg->l2h); /* If we require osmux and it is disabled.. fail */ if (nat_osmux_only(bsc->nat->mgcp_cfg, bsc->cfg) && endp->osmux.state == OSMUX_STATE_DISABLED) { LOGP(DMGCP, LOGL_ERROR, "Failed to activate osmux endpoint 0x%x\n", ENDPOINT_NUMBER(endp)); free_chan_downstream(endp, bsc_endp, bsc); return; } /* 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, mgcp_net_src_addr(endp), endp->net_end.local_port, -1, &endp->bts_end.codec.payload_type, bsc->nat->sdp_ensure_amr_mode_set); 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("\nX-Osmux: 255") + 1]; 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 & 0xff); 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 *first_payload_type, int ensure_mode_set) { 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) { int offset; if (sscanf(token, "m=audio %*d RTP/AVP %n%d", &offset, &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 %s\n", port, &token[offset]); 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 (ensure_mode_set && !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 && first_payload_type) *first_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]); } }