diff options
Diffstat (limited to 'src/osmo-bsc_nat/bsc_mgcp_utils.c')
-rw-r--r-- | src/osmo-bsc_nat/bsc_mgcp_utils.c | 1152 |
1 files changed, 1152 insertions, 0 deletions
diff --git a/src/osmo-bsc_nat/bsc_mgcp_utils.c b/src/osmo-bsc_nat/bsc_mgcp_utils.c new file mode 100644 index 000000000..48847865c --- /dev/null +++ b/src/osmo-bsc_nat/bsc_mgcp_utils.c @@ -0,0 +1,1152 @@ +/** + * 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, 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]); + } +} |