/* (C) 2017 by Sysmocom s.f.m.c. GmbH
* All Rights Reserved
*
* Author: Philipp Maier
*
* 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
/* A pointer to the GSM network we work with. By the current paradigm,
* there can only be one gsm_network per MSC. The pointer is set once
* when calling a_init() */
static struct gsm_network *gsm_network = NULL;
/* Send DTAP message via A-interface */
int a_tx(struct msgb *msg)
{
/* FIXME: Wo is taking ownership of *msg? Do we need to free? */
struct gsm_subscriber_connection *conn;
struct msgb *msg_resp;
/* FIXME: Set this to some meaninful value! */
uint8_t link_id = 0x00;
OSMO_ASSERT(msg);
conn = (struct gsm_subscriber_connection *)msg->dst;
OSMO_ASSERT(conn);
OSMO_ASSERT(conn->a.scu);
LOGP(DMSC, LOGL_DEBUG, "Passing DTAP message from MSC to BSC (conn_id=%i)\n", conn->a.conn_id);
msg->l3h = msg->data;
msg_resp = gsm0808_create_dtap(msg, link_id);
if (!msg_resp) {
LOGP(DMSC, LOGL_ERROR, "Unable to generate BSSMAP DTAP message!\n");
return -EINVAL;
} else
LOGP(DMSC, LOGL_DEBUG, "Massage will be sent as BSSMAP DTAP message!\n");
LOGP(DMSC, LOGL_DEBUG, "N-DATA.req(%u, %s)\n", conn->a.conn_id, osmo_hexdump(msg_resp->data, msg_resp->len));
return osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg_resp);
}
/* Send Cipher mode command via A-interface */
int msc_gsm0808_tx_cipher_mode(struct gsm_subscriber_connection *conn,
int cipher, const uint8_t *key, int len, int include_imeisv)
{
/* TODO generalize for A- and Iu interfaces, don't name after 08.08 */
struct msgb *msg_resp;
struct gsm0808_encrypt_info ei;
LOGP(DMSC, LOGL_DEBUG, "Passing Cipher mode command message from MSC to BSC (conn_id=%i)\n", conn->a.conn_id);
uint8_t crm = 0x01;
uint8_t *crm_ptr = NULL;
/* Setup encryption information */
if (len > ENCRY_INFO_KEY_MAXLEN || !key) {
LOGP(DMSC, LOGL_ERROR,
"Cipher mode command message could not be generated due to invalid key! (conn_id=%i)\n",
conn->a.conn_id);
return -EINVAL;
} else {
memcpy(&ei.key, key, len);
ei.key_len = len;
}
if (include_imeisv)
crm_ptr = &crm;
ei.perm_algo[0] = (uint8_t) (1 << cipher);
ei.perm_algo_len = 1;
msg_resp = gsm0808_create_cipher(&ei, crm_ptr);
LOGP(DMSC, LOGL_DEBUG, "N-DATA.req(%u, %s)\n", conn->a.conn_id, osmo_hexdump(msg_resp->data, msg_resp->len));
return osmo_sccp_tx_data_msg(conn->a.scu, conn->a.conn_id, msg_resp);
}
/* Page a subscriber via A-interface */
int a_page(const char *imsi, uint32_t tmsi, uint16_t lac)
{
struct bsc_addr *addr;
struct llist_head *bsc_addr_list = get_bsc_addr_list();
struct gsm0808_cell_id_list cil;
int rc = -EINVAL;
cil.id_discr = CELL_IDENT_LAC;
cil.id_list_lac[0] = lac;
cil.id_list_len = 1;
/* Deliver paging request to all known BSCs */
llist_for_each_entry(addr, bsc_addr_list, list) {
LOGP(DMSC, LOGL_DEBUG, "Passing paging message from MSC to BSC %s (imsi=%s, tmsi=0x%08x, lac=%u)\n",
osmo_sccp_addr_dump(&addr->calling_addr), imsi, tmsi, lac);
osmo_sccp_tx_unitdata_msg(addr->scu, &addr->called_addr, &addr->calling_addr,
gsm0808_create_paging(imsi, &tmsi, &cil, NULL));
rc = 0;
}
if (rc != 0)
LOGP(DMSC, LOGL_ERROR, "Could not deliver paging because no BSC is available!\n");
return rc;
}
/* Send assignment request via A-interface */
int a_assign(struct gsm_trans *trans)
{
/* FIXME: Implementation is still missing! */
printf
("ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN ASSIGN \n");
return -ENOTSUP;
}
/* Callback function, called by the SSCP stack when data arrives */
static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
{
struct osmo_sccp_user *scu = _scu;
struct osmo_scu_prim *scu_prim = (struct osmo_scu_prim *)oph;
int rc = 0;
struct conn_info conn_info;
memset(&conn_info, 0, sizeof(conn_info));
conn_info.network = gsm_network;
switch (OSMO_PRIM_HDR(&scu_prim->oph)) {
case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
/* Handle inbound connection indication */
conn_info.conn_id = scu_prim->u.connect.conn_id;
conn_info.called_addr = &scu_prim->u.connect.called_addr;
conn_info.calling_addr = &scu_prim->u.connect.calling_addr;
osmo_sccp_tx_conn_resp(scu, scu_prim->u.connect.conn_id, &scu_prim->u.connect.called_addr, NULL, 0);
if (msgb_l2len(oph->msg) > 0) {
LOGP(DMSC, LOGL_DEBUG, "N-CONNECT.ind(%u, %s)\n",
scu_prim->u.connect.conn_id, osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
rc = msc_handle_dt1(scu, &conn_info, oph->msg);
} else
LOGP(DMSC, LOGL_DEBUG, "N-CONNECT.ind(%u)\n", scu_prim->u.connect.conn_id);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
/* Handle incoming connection oriented data */
conn_info.conn_id = scu_prim->u.data.conn_id;
LOGP(DMSC, LOGL_DEBUG, "N-DATA.ind(%u, %s)\n",
scu_prim->u.data.conn_id, osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
msc_handle_dt1(scu, &conn_info, oph->msg);
break;
case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
/* Handle inbound UNITDATA */
conn_info.called_addr = &scu_prim->u.unitdata.called_addr;
conn_info.calling_addr = &scu_prim->u.unitdata.calling_addr;
msc_handle_udt(scu, &conn_info, oph->msg);
break;
default:
LOGP(DMSC, LOGL_ERROR, "Unhandled SIGTRAN primitive: %u:%u\n", oph->primitive, oph->operation);
break;
}
return rc;
}
/* Initalize A interface connection between to MSC and BSC */
int a_init(void *ctx, const char *name, uint32_t local_pc,
const char *listen_addr, const char *remote_addr, uint16_t local_port, struct gsm_network *network)
{
/* FIXME: Clean this up! */
/* FIXME: Don't use the simple_server, use the simple_client instead! */
#define RECEIVER_PC 23
#define SSN_BSSAP 254 /* SCCP_SSN_BSSAP */
#define SENDER_PC 1
struct osmo_sccp_instance *sccp;
gsm_network = network;
osmo_ss7_init();
sccp = osmo_sccp_simple_server(NULL, SENDER_PC, OSMO_SS7_ASP_PROT_M3UA, -1, "127.0.0.2");
/* Why? */
osmo_sccp_simple_server_add_clnt(sccp, OSMO_SS7_ASP_PROT_M3UA, "RECEIVER", RECEIVER_PC, -1, 0, NULL);
osmo_sccp_user_bind(sccp, "echo", &sccp_sap_up, SSN_BSSAP);
return 0;
}