518 lines
13 KiB
C
518 lines
13 KiB
C
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/* BSC Multiplexer/NAT Utilities */
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/*
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* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
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* (C) 2010 by On-Waves
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <openbsc/bsc_nat.h>
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#include <openbsc/bsc_nat_sccp.h>
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#include <openbsc/bsc_msc.h>
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#include <openbsc/gsm_data.h>
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#include <openbsc/debug.h>
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#include <openbsc/ipaccess.h>
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#include <osmocore/linuxlist.h>
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#include <osmocore/talloc.h>
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#include <osmocore/gsm0808.h>
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#include <osmocore/protocol/gsm_08_08.h>
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#include <osmocom/sccp/sccp.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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static const struct rate_ctr_desc bsc_cfg_ctr_description[] = {
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[BCFG_CTR_SCCP_CONN] = { "sccp.conn", "SCCP Connections "},
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[BCFG_CTR_SCCP_CALLS] = { "sccp.calls", "SCCP Assignment Commands "},
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[BCFG_CTR_NET_RECONN] = { "net.reconnects", "Network reconnects "},
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[BCFG_CTR_DROPPED_SCCP] = { "dropped.sccp", "Dropped SCCP connections."},
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[BCFG_CTR_DROPPED_CALLS] = { "dropped.calls", "Dropped active calls. "},
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};
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static const struct rate_ctr_group_desc bsc_cfg_ctrg_desc = {
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.group_name_prefix = "nat.bsc",
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.group_description = "NAT BSC Statistics",
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.num_ctr = ARRAY_SIZE(bsc_cfg_ctr_description),
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.ctr_desc = bsc_cfg_ctr_description,
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};
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struct bsc_nat *bsc_nat_alloc(void)
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{
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struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat);
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if (!nat)
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return NULL;
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INIT_LLIST_HEAD(&nat->sccp_connections);
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INIT_LLIST_HEAD(&nat->bsc_connections);
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INIT_LLIST_HEAD(&nat->bsc_configs);
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INIT_LLIST_HEAD(&nat->access_lists);
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nat->stats.sccp.conn = counter_alloc("nat.sccp.conn");
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nat->stats.sccp.calls = counter_alloc("nat.sccp.calls");
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nat->stats.bsc.reconn = counter_alloc("nat.bsc.conn");
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nat->stats.bsc.auth_fail = counter_alloc("nat.bsc.auth_fail");
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nat->stats.msc.reconn = counter_alloc("nat.msc.conn");
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nat->msc_ip = talloc_strdup(nat, "127.0.0.1");
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nat->msc_port = 5000;
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nat->auth_timeout = 2;
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nat->ping_timeout = 20;
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nat->pong_timeout = 5;
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return nat;
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}
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void bsc_nat_set_msc_ip(struct bsc_nat *nat, const char *ip)
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{
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if (nat->msc_ip)
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talloc_free(nat->msc_ip);
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nat->msc_ip = talloc_strdup(nat, ip);
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}
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struct bsc_connection *bsc_connection_alloc(struct bsc_nat *nat)
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{
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struct bsc_connection *con = talloc_zero(nat, struct bsc_connection);
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if (!con)
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return NULL;
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con->nat = nat;
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write_queue_init(&con->write_queue, 100);
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return con;
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}
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struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token, unsigned int lac)
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{
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struct bsc_config *conf = talloc_zero(nat, struct bsc_config);
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if (!conf)
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return NULL;
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conf->token = talloc_strdup(conf, token);
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conf->lac = lac;
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conf->nr = nat->num_bsc;
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conf->nat = nat;
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llist_add_tail(&conf->entry, &nat->bsc_configs);
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++nat->num_bsc;
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conf->stats.ctrg = rate_ctr_group_alloc(conf, &bsc_cfg_ctrg_desc, conf->lac);
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if (!conf->stats.ctrg) {
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talloc_free(conf);
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return NULL;
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}
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return conf;
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}
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void sccp_connection_destroy(struct sccp_connections *conn)
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{
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LOGP(DNAT, LOGL_DEBUG, "Destroy 0x%x <-> 0x%x mapping for con %p\n",
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sccp_src_ref_to_int(&conn->real_ref),
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sccp_src_ref_to_int(&conn->patched_ref), conn->bsc);
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bsc_mgcp_dlcx(conn);
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llist_del(&conn->list_entry);
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talloc_free(conn);
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}
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struct bsc_connection *bsc_nat_find_bsc(struct bsc_nat *nat, struct msgb *msg, int *lac_out)
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{
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struct bsc_connection *bsc;
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int data_length;
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const uint8_t *data;
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struct tlv_parsed tp;
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int i = 0;
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*lac_out = -1;
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if (!msg->l3h || msgb_l3len(msg) < 3) {
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LOGP(DNAT, LOGL_ERROR, "Paging message is too short.\n");
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return NULL;
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}
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tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0);
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if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) {
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LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n");
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return NULL;
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}
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data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
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data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
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/* No need to try a different BSS */
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if (data[0] == CELL_IDENT_BSS) {
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return NULL;
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} else if (data[0] != CELL_IDENT_LAC) {
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LOGP(DNAT, LOGL_ERROR, "Unhandled cell ident discrminator: %d\n", data[0]);
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return NULL;
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}
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/* Currently we only handle one BSC */
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for (i = 1; i < data_length - 1; i += 2) {
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unsigned int _lac = ntohs(*(unsigned int *) &data[i]);
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*lac_out = _lac;
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llist_for_each_entry(bsc, &nat->bsc_connections, list_entry) {
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if (!bsc->cfg)
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continue;
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if (!bsc->authenticated || _lac != bsc->cfg->lac)
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continue;
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return bsc;
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}
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}
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return NULL;
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}
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int bsc_write_mgcp(struct bsc_connection *bsc, const uint8_t *data, unsigned int length)
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{
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struct msgb *msg;
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if (length > 4096 - 128) {
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LOGP(DINP, LOGL_ERROR, "Can not send message of that size.\n");
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return -1;
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}
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msg = msgb_alloc_headroom(4096, 128, "to-bsc");
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if (!msg) {
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LOGP(DINP, LOGL_ERROR, "Failed to allocate memory for BSC msg.\n");
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return -1;
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}
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/* copy the data */
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msg->l3h = msgb_put(msg, length);
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memcpy(msg->l3h, data, length);
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return bsc_write(bsc, msg, NAT_IPAC_PROTO_MGCP);
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}
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int bsc_write(struct bsc_connection *bsc, struct msgb *msg, int proto)
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{
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/* prepend the header */
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ipaccess_prepend_header(msg, proto);
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if (write_queue_enqueue(&bsc->write_queue, msg) != 0) {
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LOGP(DINP, LOGL_ERROR, "Failed to enqueue the write.\n");
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msgb_free(msg);
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return -1;
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}
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return 0;
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}
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static int lst_check_allow(struct bsc_nat_acc_lst *lst, const char *mi_string)
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{
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struct bsc_nat_acc_lst_entry *entry;
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llist_for_each_entry(entry, &lst->fltr_list, list) {
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if (!entry->imsi_allow)
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continue;
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if (regexec(&entry->imsi_allow_re, mi_string, 0, NULL, 0) == 0)
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return 0;
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}
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return 1;
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}
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static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string)
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{
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struct bsc_nat_acc_lst_entry *entry;
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llist_for_each_entry(entry, &lst->fltr_list, list) {
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if (!entry->imsi_deny)
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continue;
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if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0)
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return 0;
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}
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return 1;
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}
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/* apply white/black list */
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static int auth_imsi(struct bsc_connection *bsc, const char *mi_string)
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{
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/*
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* Now apply blacklist/whitelist of the BSC and the NAT.
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* 1.) Reject if the IMSI is not allowed at the BSC
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* 2.) Allow directly if the IMSI is allowed at the BSC
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* 3.) Reject if the IMSI not allowed at the global level.
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* 4.) Allow directly if the IMSI is allowed at the global level
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*/
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struct bsc_nat_acc_lst *nat_lst = NULL;
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struct bsc_nat_acc_lst *bsc_lst = NULL;
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bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name);
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nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name);
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if (bsc_lst) {
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/* 1. BSC deny */
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if (lst_check_deny(bsc_lst, mi_string) == 0) {
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LOGP(DNAT, LOGL_ERROR,
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"Filtering %s by imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr);
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return -2;
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}
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/* 2. BSC allow */
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if (lst_check_allow(bsc_lst, mi_string) == 0)
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return 0;
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}
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/* 3. NAT deny */
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if (nat_lst) {
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if (lst_check_deny(nat_lst, mi_string) == 0) {
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LOGP(DNAT, LOGL_ERROR,
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"Filtering %s by nat imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr);
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return -3;
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}
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}
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return 0;
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}
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static int _cr_check_loc_upd(struct bsc_connection *bsc, uint8_t *data, unsigned int length)
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{
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uint8_t mi_type;
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struct gsm48_loc_upd_req *lu;
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char mi_string[GSM48_MI_SIZE];
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if (length < sizeof(*lu)) {
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LOGP(DNAT, LOGL_ERROR,
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"LU does not fit. Length is %d \n", length);
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return -1;
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}
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lu = (struct gsm48_loc_upd_req *) data;
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mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
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/*
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* We can only deal with the IMSI. This will fail for a phone that
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* will send the TMSI of a previous network to us.
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*/
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if (mi_type != GSM_MI_TYPE_IMSI)
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return 0;
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gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
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return auth_imsi(bsc, mi_string);
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}
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static int _cr_check_cm_serv_req(struct bsc_connection *bsc, uint8_t *data, unsigned int length)
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{
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static const uint32_t classmark_offset =
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offsetof(struct gsm48_service_request, classmark);
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char mi_string[GSM48_MI_SIZE];
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uint8_t mi_type;
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int rc;
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struct gsm48_service_request *req;
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/* unfortunately in Phase1 the classmark2 length is variable */
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if (length < sizeof(*req)) {
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LOGP(DNAT, LOGL_ERROR,
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"CM Serv Req does not fit. Length is %d\n", length);
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return -1;
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}
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req = (struct gsm48_service_request *) data;
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rc = gsm48_extract_mi((uint8_t *) &req->classmark,
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length - classmark_offset, mi_string, &mi_type);
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if (rc < 0) {
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LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc);
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return -1;
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}
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/* we have to let the TMSI or such pass */
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if (mi_type != GSM_MI_TYPE_IMSI)
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return 0;
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return auth_imsi(bsc, mi_string);
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}
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static int _cr_check_pag_resp(struct bsc_connection *bsc, uint8_t *data, unsigned int length)
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{
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struct gsm48_pag_resp *resp;
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char mi_string[GSM48_MI_SIZE];
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uint8_t mi_type;
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if (length < sizeof(*resp)) {
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LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length);
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return -1;
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}
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resp = (struct gsm48_pag_resp *) data;
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if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) {
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LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n");
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return -1;
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}
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/* we need to let it pass for now */
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if (mi_type != GSM_MI_TYPE_IMSI)
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return 0;
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return auth_imsi(bsc, mi_string);
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}
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/* Filter out CR data... */
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int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed, int *con_type)
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{
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struct tlv_parsed tp;
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struct gsm48_hdr *hdr48;
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int hdr48_len;
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int len;
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*con_type = NAT_CON_TYPE_NONE;
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if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) {
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LOGP(DNAT, LOGL_ERROR,
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"Rejecting CR message due wrong GSM Type %d\n", parsed->gsm_type);
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return -1;
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}
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/* the parsed has had some basic l3 length check */
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len = msg->l3h[1];
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if (msgb_l3len(msg) - 3 < len) {
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LOGP(DNAT, LOGL_ERROR,
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"The CR Data has not enough space...\n");
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return -1;
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}
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msg->l4h = &msg->l3h[3];
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len -= 1;
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tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h, len, 0, 0);
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if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) {
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LOGP(DNAT, LOGL_ERROR, "CR Data does not contain layer3 information.\n");
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return -1;
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}
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hdr48_len = TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION);
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if (hdr48_len < sizeof(*hdr48)) {
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LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n");
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return -1;
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}
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hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION);
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if (hdr48->proto_discr == GSM48_PDISC_MM &&
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hdr48->msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
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*con_type = NAT_CON_TYPE_LU;
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return _cr_check_loc_upd(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48));
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} else if (hdr48->proto_discr == GSM48_PDISC_MM &&
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hdr48->msg_type == GSM48_MT_MM_CM_SERV_REQ) {
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*con_type = NAT_CON_TYPE_CM_SERV_REQ;
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return _cr_check_cm_serv_req(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48));
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} else if (hdr48->proto_discr == GSM48_PDISC_RR &&
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hdr48->msg_type == GSM48_MT_RR_PAG_RESP) {
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*con_type = NAT_CON_TYPE_PAG_RESP;
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return _cr_check_pag_resp(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48));
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} else {
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/* We only want to filter the above, let other things pass */
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*con_type = NAT_CON_TYPE_OTHER;
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return 0;
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}
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}
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void bsc_parse_reg(void *ctx, regex_t *reg, char **imsi, int argc, const char **argv)
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{
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if (*imsi) {
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talloc_free(*imsi);
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*imsi = NULL;
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}
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regfree(reg);
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if (argc > 0) {
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*imsi = talloc_strdup(ctx, argv[0]);
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regcomp(reg, argv[0], 0);
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}
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}
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static const char *con_types [] = {
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[NAT_CON_TYPE_NONE] = "n/a",
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[NAT_CON_TYPE_LU] = "Location Update",
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[NAT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req",
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[NAT_CON_TYPE_PAG_RESP] = "Paging Response",
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[NAT_CON_TYPE_LOCAL_REJECT] = "Local Reject",
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[NAT_CON_TYPE_OTHER] = "Other",
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};
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const char *bsc_con_type_to_string(int type)
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{
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return con_types[type];
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}
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struct bsc_nat_acc_lst *bsc_nat_acc_lst_find(struct bsc_nat *nat, const char *name)
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{
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struct bsc_nat_acc_lst *lst;
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if (!name)
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return NULL;
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llist_for_each_entry(lst, &nat->access_lists, list)
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if (strcmp(lst->name, name) == 0)
|
|
return lst;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
struct bsc_nat_acc_lst *bsc_nat_acc_lst_get(struct bsc_nat *nat, const char *name)
|
|
{
|
|
struct bsc_nat_acc_lst *lst;
|
|
|
|
lst = bsc_nat_acc_lst_find(nat, name);
|
|
if (lst)
|
|
return lst;
|
|
|
|
lst = talloc_zero(nat, struct bsc_nat_acc_lst);
|
|
if (!lst) {
|
|
LOGP(DNAT, LOGL_ERROR, "Failed to allocate access list");
|
|
return NULL;
|
|
}
|
|
|
|
INIT_LLIST_HEAD(&lst->fltr_list);
|
|
lst->name = talloc_strdup(lst, name);
|
|
llist_add_tail(&lst->list, &nat->access_lists);
|
|
return lst;
|
|
}
|
|
|
|
void bsc_nat_acc_lst_delete(struct bsc_nat_acc_lst *lst)
|
|
{
|
|
llist_del(&lst->list);
|
|
talloc_free(lst);
|
|
}
|
|
|
|
struct bsc_nat_acc_lst_entry *bsc_nat_acc_lst_entry_create(struct bsc_nat_acc_lst *lst)
|
|
{
|
|
struct bsc_nat_acc_lst_entry *entry;
|
|
|
|
entry = talloc_zero(lst, struct bsc_nat_acc_lst_entry);
|
|
if (!entry)
|
|
return NULL;
|
|
|
|
llist_add_tail(&entry->list, &lst->fltr_list);
|
|
return entry;
|
|
}
|
|
|
|
int bsc_nat_msc_is_connected(struct bsc_nat *nat)
|
|
{
|
|
return nat->msc_con->is_connected;
|
|
}
|