1 files changed, 535 insertions, 0 deletions

diff --git a/src/osmo-bsc_nat/bsc_nat_utils.c b/src/osmo-bsc_nat/bsc_nat_utils.c
new file mode 100644
index 000000000..c12b29f1f
--- /dev/null
+++ b/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -0,0 +1,535 @@
+
+/* BSC Multiplexer/NAT Utilities */
+
+/*
+ * (C) 2010-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010-2011 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_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
+#include <openbsc/bsc_msc.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/ipaccess.h>
+#include <openbsc/vty.h>
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/stats.h>
+#include <osmocom/gsm/gsm0808.h>
+#include <osmocom/gsm/ipa.h>
+
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/protocol/gsm_04_11.h>
+
+#include <osmocom/sccp/sccp.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+
+static const struct rate_ctr_desc bsc_cfg_ctr_description[] = {
+	[BCFG_CTR_SCCP_CONN]     = { "sccp.conn",      "SCCP Connections         "},
+	[BCFG_CTR_SCCP_CALLS]    = { "sccp.calls",     "SCCP Assignment Commands "},
+	[BCFG_CTR_NET_RECONN]    = { "net.reconnects", "Network reconnects       "},
+	[BCFG_CTR_DROPPED_SCCP]  = { "dropped.sccp",   "Dropped SCCP connections."},
+	[BCFG_CTR_DROPPED_CALLS] = { "dropped.calls",  "Dropped active calls.    "},
+	[BCFG_CTR_REJECTED_CR]   = { "rejected.cr",    "Rejected CR due filter   "},
+	[BCFG_CTR_REJECTED_MSG]  = { "rejected.msg",   "Rejected MSG due filter  "},
+	[BCFG_CTR_ILL_PACKET]    = { "rejected.ill",   "Rejected due parse error "},
+	[BCFG_CTR_CON_TYPE_LU]   = { "conn.lu",        "Conn Location Update     "},
+	[BCFG_CTR_CON_CMSERV_RQ] = { "conn.rq",        "Conn CM Service Req      "},
+	[BCFG_CTR_CON_PAG_RESP]  = { "conn.pag",       "Conn Paging Response     "},
+	[BCFG_CTR_CON_SSA]       = { "conn.ssa",       "Conn USSD                "},
+	[BCFG_CTR_CON_OTHER]     = { "conn.other",     "Conn Other               "},
+};
+
+static const struct rate_ctr_group_desc bsc_cfg_ctrg_desc = {
+	.group_name_prefix = "nat.bsc",
+	.group_description = "NAT BSC Statistics",
+	.num_ctr = ARRAY_SIZE(bsc_cfg_ctr_description),
+	.ctr_desc = bsc_cfg_ctr_description,
+	.class_id = OSMO_STATS_CLASS_PEER,
+};
+
+struct bsc_nat *bsc_nat_alloc(void)
+{
+	struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat);
+	if (!nat)
+		return NULL;
+
+	nat->main_dest = talloc_zero(nat, struct bsc_msc_dest);
+	if (!nat->main_dest) {
+		talloc_free(nat);
+		return NULL;
+	}
+
+	INIT_LLIST_HEAD(&nat->sccp_connections);
+	INIT_LLIST_HEAD(&nat->bsc_connections);
+	INIT_LLIST_HEAD(&nat->paging_groups);
+	INIT_LLIST_HEAD(&nat->bsc_configs);
+	INIT_LLIST_HEAD(&nat->access_lists);
+	INIT_LLIST_HEAD(&nat->dests);
+	INIT_LLIST_HEAD(&nat->num_rewr);
+	INIT_LLIST_HEAD(&nat->num_rewr_post);
+	INIT_LLIST_HEAD(&nat->smsc_rewr);
+	INIT_LLIST_HEAD(&nat->tpdest_match);
+	INIT_LLIST_HEAD(&nat->sms_clear_tp_srr);
+	INIT_LLIST_HEAD(&nat->sms_num_rewr);
+
+	nat->stats.sccp.conn = osmo_counter_alloc("nat.sccp.conn");
+	nat->stats.sccp.calls = osmo_counter_alloc("nat.sccp.calls");
+	nat->stats.bsc.reconn = osmo_counter_alloc("nat.bsc.conn");
+	nat->stats.bsc.auth_fail = osmo_counter_alloc("nat.bsc.auth_fail");
+	nat->stats.msc.reconn = osmo_counter_alloc("nat.msc.conn");
+	nat->stats.ussd.reconn = osmo_counter_alloc("nat.ussd.conn");
+	nat->auth_timeout = 2;
+	nat->ping_timeout = 20;
+	nat->pong_timeout = 5;
+
+	llist_add(&nat->main_dest->list, &nat->dests);
+	nat->main_dest->ip = talloc_strdup(nat, "127.0.0.1");
+	nat->main_dest->port = 5000;
+
+	return nat;
+}
+
+void bsc_nat_free(struct bsc_nat *nat)
+{
+	struct bsc_config *cfg, *tmp;
+	struct bsc_msg_acc_lst *lst, *tmp_lst;
+
+	llist_for_each_entry_safe(cfg, tmp, &nat->bsc_configs, entry)
+		bsc_config_free(cfg);
+	llist_for_each_entry_safe(lst, tmp_lst, &nat->access_lists, list)
+		bsc_msg_acc_lst_delete(lst);
+
+	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, NULL);
+	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr_post, NULL);
+	bsc_nat_num_rewr_entry_adapt(nat, &nat->sms_clear_tp_srr, NULL);
+	bsc_nat_num_rewr_entry_adapt(nat, &nat->sms_num_rewr, NULL);
+	bsc_nat_num_rewr_entry_adapt(nat, &nat->tpdest_match, NULL);
+
+	osmo_counter_free(nat->stats.sccp.conn);
+	osmo_counter_free(nat->stats.sccp.calls);
+	osmo_counter_free(nat->stats.bsc.reconn);
+	osmo_counter_free(nat->stats.bsc.auth_fail);
+	osmo_counter_free(nat->stats.msc.reconn);
+	osmo_counter_free(nat->stats.ussd.reconn);
+	talloc_free(nat->mgcp_cfg);
+	talloc_free(nat);
+}
+
+void bsc_nat_set_msc_ip(struct bsc_nat *nat, const char *ip)
+{
+	osmo_talloc_replace_string(nat, &nat->main_dest->ip, ip);
+}
+
+struct bsc_connection *bsc_connection_alloc(struct bsc_nat *nat)
+{
+	struct bsc_connection *con = talloc_zero(nat, struct bsc_connection);
+	if (!con)
+		return NULL;
+
+	con->nat = nat;
+	osmo_wqueue_init(&con->write_queue, 100);
+	INIT_LLIST_HEAD(&con->cmd_pending);
+	INIT_LLIST_HEAD(&con->pending_dlcx);
+	return con;
+}
+
+struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token,
+				    unsigned int number)
+{
+	struct bsc_config *conf = talloc_zero(nat, struct bsc_config);
+	if (!conf)
+		return NULL;
+
+	conf->token = talloc_strdup(conf, token);
+	conf->nr = number;
+	conf->nat = nat;
+	conf->max_endpoints = 32;
+	conf->paging_group = PAGIN_GROUP_UNASSIGNED;
+
+	INIT_LLIST_HEAD(&conf->lac_list);
+
+	llist_add_tail(&conf->entry, &nat->bsc_configs);
+	++nat->num_bsc;
+
+	conf->stats.ctrg = rate_ctr_group_alloc(conf, &bsc_cfg_ctrg_desc, conf->nr);
+	if (!conf->stats.ctrg) {
+		llist_del(&conf->entry);
+		talloc_free(conf);
+		return NULL;
+	}
+
+	return conf;
+}
+
+struct bsc_config *bsc_config_by_token(struct bsc_nat *nat, const char *token, int len)
+{
+	struct bsc_config *conf;
+
+	llist_for_each_entry(conf, &nat->bsc_configs, entry) {
+		/*
+		 * Add the '\0' of the token for the memcmp, the IPA messages
+		 * for some reason added null termination.
+		 */
+		const int token_len = strlen(conf->token) + 1;
+
+		if (token_len == len && memcmp(conf->token, token, token_len) == 0)
+			return conf;
+	}
+
+	return NULL;
+}
+
+void bsc_config_free(struct bsc_config *cfg)
+{
+	llist_del(&cfg->entry);
+	rate_ctr_group_free(cfg->stats.ctrg);
+	cfg->nat->num_bsc--;
+	OSMO_ASSERT(cfg->nat->num_bsc >= 0)
+	talloc_free(cfg);
+}
+
+static void _add_lac(void *ctx, struct llist_head *list, int _lac)
+{
+	struct bsc_lac_entry *lac;
+
+	llist_for_each_entry(lac, list, entry)
+		if (lac->lac == _lac)
+			return;
+
+	lac = talloc_zero(ctx, struct bsc_lac_entry);
+	if (!lac) {
+		LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n");
+		return;
+	}
+
+	lac->lac = _lac;
+	llist_add_tail(&lac->entry, list);
+}
+
+static void _del_lac(struct llist_head *list, int _lac)
+{
+	struct bsc_lac_entry *lac;
+
+	llist_for_each_entry(lac, list, entry)
+		if (lac->lac == _lac) {
+			llist_del(&lac->entry);
+			talloc_free(lac);
+			return;
+		}
+}
+
+void bsc_config_add_lac(struct bsc_config *cfg, int _lac)
+{
+	_add_lac(cfg, &cfg->lac_list, _lac);
+}
+
+void bsc_config_del_lac(struct bsc_config *cfg, int _lac)
+{
+	_del_lac(&cfg->lac_list, _lac);
+}
+
+struct bsc_nat_paging_group *bsc_nat_paging_group_create(struct bsc_nat *nat, int group)
+{
+	struct bsc_nat_paging_group *pgroup;
+
+	pgroup = talloc_zero(nat, struct bsc_nat_paging_group);
+	if (!pgroup) {
+		LOGP(DNAT, LOGL_ERROR, "Failed to allocate a paging group.\n");
+		return NULL;
+	}
+
+	pgroup->nr = group;
+	INIT_LLIST_HEAD(&pgroup->lists);
+	llist_add_tail(&pgroup->entry, &nat->paging_groups);
+	return pgroup;
+}
+
+void bsc_nat_paging_group_delete(struct bsc_nat_paging_group *pgroup)
+{
+	llist_del(&pgroup->entry);
+	talloc_free(pgroup);
+}
+
+struct bsc_nat_paging_group *bsc_nat_paging_group_num(struct bsc_nat *nat, int group)
+{
+	struct bsc_nat_paging_group *pgroup;
+
+	llist_for_each_entry(pgroup, &nat->paging_groups, entry)
+		if (pgroup->nr == group)
+			return pgroup;
+
+	return NULL;
+}
+
+void bsc_nat_paging_group_add_lac(struct bsc_nat_paging_group *pgroup, int lac)
+{
+	_add_lac(pgroup, &pgroup->lists, lac);
+}
+
+void bsc_nat_paging_group_del_lac(struct bsc_nat_paging_group *pgroup, int lac)
+{
+	_del_lac(&pgroup->lists, lac);
+}
+
+int bsc_config_handles_lac(struct bsc_config *cfg, int lac_nr)
+{
+	struct bsc_nat_paging_group *pgroup;
+	struct bsc_lac_entry *entry;
+
+	llist_for_each_entry(entry, &cfg->lac_list, entry)
+		if (entry->lac == lac_nr)
+			return 1;
+
+	/* now lookup the paging group */
+	pgroup = bsc_nat_paging_group_num(cfg->nat, cfg->paging_group);
+	if (!pgroup)
+		return 0;
+
+	llist_for_each_entry(entry, &pgroup->lists, entry)
+		if (entry->lac == lac_nr)
+			return 1;
+
+	return 0;
+}
+
+void sccp_connection_destroy(struct nat_sccp_connection *conn)
+{
+	LOGP(DNAT, LOGL_DEBUG, "Destroy 0x%x <-> 0x%x mapping for con %p\n",
+	     sccp_src_ref_to_int(&conn->real_ref),
+	     sccp_src_ref_to_int(&conn->patched_ref), conn->bsc);
+	bsc_mgcp_dlcx(conn);
+	llist_del(&conn->list_entry);
+	talloc_free(conn);
+}
+
+
+int bsc_nat_find_paging(struct msgb *msg,
+			const uint8_t **out_data, int *out_leng)
+{
+	int data_length;
+	const uint8_t *data;
+	struct tlv_parsed tp;
+
+	if (!msg->l3h || msgb_l3len(msg) < 3) {
+		LOGP(DNAT, LOGL_ERROR, "Paging message is too short.\n");
+		return -1;
+	}
+
+	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0);
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) {
+		LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n");
+		return -2;
+	}
+
+	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
+	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST);
+
+	/* No need to try a different BSS */
+	if (data[0] == CELL_IDENT_BSS) {
+		return -3;
+	} else if (data[0] != CELL_IDENT_LAC) {
+		LOGP(DNAT, LOGL_ERROR, "Unhandled cell ident discrminator: %d\n", data[0]);
+		return -4;
+	}
+
+	*out_data = &data[1];
+	*out_leng = data_length - 1;
+	return 0;
+}
+
+int bsc_write_mgcp(struct bsc_connection *bsc, const uint8_t *data, unsigned int length)
+{
+	struct msgb *msg;
+
+	if (length > 4096 - 128) {
+		LOGP(DLINP, LOGL_ERROR, "Can not send message of that size.\n");
+		return -1;
+	}
+
+	msg = msgb_alloc_headroom(4096, 128, "to-bsc");
+	if (!msg) {
+		LOGP(DLINP, LOGL_ERROR, "Failed to allocate memory for BSC msg.\n");
+		return -1;
+	}
+
+	/* copy the data */
+	msg->l3h = msgb_put(msg, length);
+	memcpy(msg->l3h, data, length);
+
+        return bsc_write(bsc, msg, IPAC_PROTO_MGCP_OLD);
+}
+
+int bsc_write(struct bsc_connection *bsc, struct msgb *msg, int proto)
+{
+	return bsc_do_write(&bsc->write_queue, msg, proto);
+}
+
+int bsc_do_write(struct osmo_wqueue *queue, struct msgb *msg, int proto)
+{
+	/* prepend the header */
+	ipa_prepend_header(msg, proto);
+	return bsc_write_msg(queue, msg);
+}
+
+int bsc_write_msg(struct osmo_wqueue *queue, struct msgb *msg)
+{
+	if (osmo_wqueue_enqueue(queue, msg) != 0) {
+		LOGP(DLINP, LOGL_ERROR, "Failed to enqueue the write.\n");
+		msgb_free(msg);
+		return -1;
+	}
+
+	return 0;
+}
+
+struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed,
+				  struct msgb *msg, uint32_t *len)
+{
+	/* gsm_type is actually the size of the dtap */
+	*len = parsed->gsm_type;
+	if (*len < msgb_l3len(msg) - 3) {
+		LOGP(DNAT, LOGL_ERROR, "Not enough space for DTAP.\n");
+		return NULL;
+	}
+
+	if (msgb_l3len(msg) - 3 < msg->l3h[2]) {
+		LOGP(DNAT, LOGL_ERROR,
+		     "GSM48 payload does not fit: %d %d\n",
+		     msg->l3h[2], msgb_l3len(msg) - 3);
+		return NULL;
+	}
+
+	msg->l4h = &msg->l3h[3];
+	return (struct gsm48_hdr *) msg->l4h;
+}
+
+static const char *con_types [] = {
+	[FLT_CON_TYPE_NONE] = "n/a",
+	[FLT_CON_TYPE_LU] = "Location Update",
+	[FLT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req",
+	[FLT_CON_TYPE_PAG_RESP] = "Paging Response",
+	[FLT_CON_TYPE_SSA] = "Supplementar Service Activation",
+	[FLT_CON_TYPE_LOCAL_REJECT] = "Local Reject",
+	[FLT_CON_TYPE_OTHER] = "Other",
+};
+
+const char *bsc_con_type_to_string(int type)
+{
+	return con_types[type];
+}
+
+int bsc_nat_msc_is_connected(struct bsc_nat *nat)
+{
+	return nat->msc_con->is_connected;
+}
+
+static const int con_to_ctr[] = {
+	[FLT_CON_TYPE_NONE]		= -1,
+	[FLT_CON_TYPE_LU]		= BCFG_CTR_CON_TYPE_LU,
+	[FLT_CON_TYPE_CM_SERV_REQ]	= BCFG_CTR_CON_CMSERV_RQ,
+	[FLT_CON_TYPE_PAG_RESP]		= BCFG_CTR_CON_PAG_RESP,
+	[FLT_CON_TYPE_SSA]		= BCFG_CTR_CON_SSA,
+	[FLT_CON_TYPE_LOCAL_REJECT]	= -1,
+	[FLT_CON_TYPE_OTHER]		= BCFG_CTR_CON_OTHER,
+};
+
+int bsc_conn_type_to_ctr(struct nat_sccp_connection *conn)
+{
+	return con_to_ctr[conn->filter_state.con_type];
+}
+
+int bsc_write_cb(struct osmo_fd *bfd, struct msgb *msg)
+{
+	int rc;
+
+	rc = write(bfd->fd, msg->data, msg->len);
+	if (rc != msg->len)
+		LOGP(DNAT, LOGL_ERROR, "Failed to write message to the BSC.\n");
+
+	return rc;
+}
+
+static void extract_lac(const uint8_t *data, uint16_t *lac, uint16_t *ci)
+{
+	memcpy(lac, &data[0], sizeof(*lac));
+	memcpy(ci, &data[2], sizeof(*ci));
+
+	*lac = ntohs(*lac);
+	*ci = ntohs(*ci);
+}
+
+int bsc_nat_extract_lac(struct bsc_connection *bsc,
+			struct nat_sccp_connection *con,
+			struct bsc_nat_parsed *parsed, struct msgb *msg)
+{
+	int data_length;
+	const uint8_t *data;
+	struct tlv_parsed tp;
+	uint16_t lac, ci;
+
+	if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) {
+		LOGP(DNAT, LOGL_ERROR, "Can only extract LAC from Complete Layer3\n");
+		return -1;
+	}
+
+	if (!msg->l3h || msgb_l3len(msg) < 3) {
+		LOGP(DNAT, LOGL_ERROR, "Complete Layer3 mssage is too short.\n");
+		return -1;
+	}
+
+	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0);
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER)) {
+		LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n");
+		return -2;
+	}
+
+	data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER);
+	data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER);
+
+	/* Attemt to get the LAC/CI from it */
+	if (data[0] == CELL_IDENT_WHOLE_GLOBAL) {
+		if (data_length != 8) {
+			LOGP(DNAT, LOGL_ERROR,
+				"Ident too short: %d\n", data_length);
+			return -3;
+		}
+		extract_lac(&data[1 + 3], &lac, &ci);
+	} else if (data[0] == CELL_IDENT_LAC_AND_CI) {
+		if (data_length != 5) {
+			LOGP(DNAT, LOGL_ERROR,
+				"Ident too short: %d\n", data_length);
+			return -3;
+		}
+		extract_lac(&data[1], &lac, &ci);
+	} else {
+		LOGP(DNAT, LOGL_ERROR,
+			"Unhandled cell identifier: %d\n", data[0]);
+		return -1;
+	}
+
+	con->lac = lac;
+	con->ci = ci;
+	return 0;
+}