filter: Move the gsm 04.08 filter to a common place

For customer requirements we want to be able to do
filtering on the BSC as well. The same messages need
to be scanned and the same access-lists will be looked
at. In the future we might even split traffic based
on the IMSI. Begin with moving the code to a new top
level directory and then renaming and removing the
nat dependency.

1 files changed, 0 insertions, 443 deletions

diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
deleted file mode 100644
index 64f6d7347..000000000
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
+++ /dev/null
@@ -1,443 +0,0 @@
-/*
- * Access filtering
- */
-/*
- * (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_sccp.h>
-#include <openbsc/bsc_msc.h>
-#include <openbsc/gsm_data.h>
-#include <openbsc/debug.h>
-#include <openbsc/ipaccess.h>
-
-#include <osmocom/core/linuxlist.h>
-#include <osmocom/core/talloc.h>
-#include <osmocom/gsm/gsm0808.h>
-
-#include <osmocom/gsm/protocol/gsm_08_08.h>
-#include <osmocom/gsm/protocol/gsm_04_11.h>
-
-#include <osmocom/sccp/sccp.h>
-
-int bsc_nat_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu)
-{
-	struct bsc_nat_barr_entry *n;
-	n = rb_entry(root->rb_node, struct bsc_nat_barr_entry, node);
-
-	while (n) {
-		int rc = strcmp(imsi, n->imsi);
-		if (rc == 0) {
-			*cm = n->cm_reject_cause;
-			*lu = n->lu_reject_cause;
-			return 1;
-		}
-
-		n = rb_entry(
-			(rc < 0) ? n->node.rb_left : n->node.rb_right,
-			struct bsc_nat_barr_entry, node);
-	};
-
-	return 0;
-}
-
-static int insert_barr_node(struct bsc_nat_barr_entry *entry, struct rb_root *root)
-{
-	struct rb_node **new = &root->rb_node, *parent = NULL;
-
-	while (*new) {
-		int rc;
-		struct bsc_nat_barr_entry *this;
-		this = rb_entry(*new, struct bsc_nat_barr_entry, node);
-		parent = *new;
-
-		rc = strcmp(entry->imsi, this->imsi);
-		if (rc < 0)
-			new = &((*new)->rb_left);
-		else if (rc > 0)
-			new = &((*new)->rb_right);
-		else {
-			LOGP(DNAT, LOGL_ERROR,
-				"Duplicate entry for IMSI(%s)\n", entry->imsi);
-			talloc_free(entry);
-			return -1;
-		}
-	}
-
-	rb_link_node(&entry->node, parent, new);
-	rb_insert_color(&entry->node, root);
-	return 0;
-}
-
-int bsc_nat_barr_adapt(void *ctx, struct rb_root *root,
-			const struct osmo_config_list *list)
-{
-	struct osmo_config_entry *cfg_entry;
-	int err = 0;
-
-	/* free the old data */
-	while (!RB_EMPTY_ROOT(root)) {
-		struct rb_node *node = rb_first(root);
-		rb_erase(node, root);
-		talloc_free(node);
-	}
-
-	if (!list)
-		return 0;
-
-	/* now adapt the new list */
-	llist_for_each_entry(cfg_entry, &list->entry, list) {
-		struct bsc_nat_barr_entry *entry;
-		entry = talloc_zero(ctx, struct bsc_nat_barr_entry);
-		if (!entry) {
-			LOGP(DNAT, LOGL_ERROR,
-				"Allocation of the barr entry failed.\n");
-			continue;
-		}
-
-		entry->imsi = talloc_strdup(entry, cfg_entry->mcc);
-		entry->cm_reject_cause = atoi(cfg_entry->mnc);
-		entry->lu_reject_cause = atoi(cfg_entry->option);
-		err |= insert_barr_node(entry, root);
-	}
-
-	return err;
-}
-
-
-static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string,
-			int *cm_cause, int *lu_cause)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	llist_for_each_entry(entry, &lst->fltr_list, list) {
-		if (!entry->imsi_deny)
-			continue;
-		if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0) {
-			*cm_cause = entry->cm_reject_cause;
-			*lu_cause = entry->lu_reject_cause;
-			return 0;
-		}
-	}
-
-	return 1;
-}
-
-/* apply white/black list */
-static int auth_imsi(struct bsc_connection *bsc, const char *imsi,
-		struct bsc_nat_reject_cause *cause)
-{
-	/*
-	 * Now apply blacklist/whitelist of the BSC and the NAT.
-	 * 1.) Check the global IMSI barr list
-	 * 2.) Allow directly if the IMSI is allowed at the BSC
-	 * 3.) Reject if the IMSI is not allowed at the BSC
-	 * 4.) Reject if the IMSI not allowed at the global level.
-	 * 5.) Allow directly if the IMSI is allowed at the global level
-	 */
-	int cm, lu;
-	struct bsc_nat_acc_lst *nat_lst = NULL;
-	struct bsc_nat_acc_lst *bsc_lst = NULL;
-
-	/* 1. global check for barred imsis */
-	if (bsc_nat_barr_find(&bsc->nat->imsi_black_list, imsi, &cm, &lu)) {
-		cause->cm_reject_cause = cm;
-		cause->lu_reject_cause = lu;
-		LOGP(DNAT, LOGL_DEBUG,
-			"Blocking subscriber IMSI %s with CM: %d LU: %d\n",
-			imsi, cm, lu);
-		return -4;
-	}
-
-
-	bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name);
-	nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name);
-
-
-	if (bsc_lst) {
-		/* 2. BSC allow */
-		if (bsc_nat_lst_check_allow(bsc_lst, imsi) == 0)
-			return 1;
-
-		/* 3. BSC deny */
-		if (lst_check_deny(bsc_lst, imsi, &cm, &lu) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr);
-			rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_BSC_FILTER]);
-			cause->cm_reject_cause = cm;
-			cause->lu_reject_cause = lu;
-			return -2;
-		}
-
-	}
-
-	/* 4. NAT deny */
-	if (nat_lst) {
-		if (lst_check_deny(nat_lst, imsi, &cm, &lu) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by nat imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr);
-			rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_NAT_FILTER]);
-			cause->cm_reject_cause = cm;
-			cause->lu_reject_cause = lu;
-			return -3;
-		}
-	}
-
-	return 1;
-}
-
-static int _cr_check_loc_upd(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     char **imsi)
-{
-	uint8_t mi_type;
-	struct gsm48_loc_upd_req *lu;
-	char mi_string[GSM48_MI_SIZE];
-
-	if (length < sizeof(*lu)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "LU does not fit. Length is %d \n", length);
-		return -1;
-	}
-
-	lu = (struct gsm48_loc_upd_req *) data;
-	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
-
-	/*
-	 * We can only deal with the IMSI. This will fail for a phone that
-	 * will send the TMSI of a previous network to us.
-	 */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _cr_check_cm_serv_req(struct bsc_connection *bsc,
-				 uint8_t *data, unsigned int length,
-				 int *con_type, char **imsi)
-{
-	static const uint32_t classmark_offset =
-				offsetof(struct gsm48_service_request, classmark);
-
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-	int rc;
-	struct gsm48_service_request *req;
-
-	/* unfortunately in Phase1 the classmark2 length is variable */
-
-	if (length < sizeof(*req)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "CM Serv Req does not fit. Length is %d\n", length);
-		return -1;
-	}
-
-	req = (struct gsm48_service_request *) data;
-	if (req->cm_service_type == 0x8)
-		*con_type = NAT_CON_TYPE_SSA;
-	rc = gsm48_extract_mi((uint8_t *) &req->classmark,
-			      length - classmark_offset, mi_string, &mi_type);
-	if (rc < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc);
-		return -1;
-	}
-
-	/* we have to let the TMSI or such pass */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _cr_check_pag_resp(struct bsc_connection *bsc,
-			      uint8_t *data, unsigned int length, char **imsi)
-{
-	struct gsm48_pag_resp *resp;
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-
-	if (length < sizeof(*resp)) {
-		LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length);
-		return -1;
-	}
-
-	resp = (struct gsm48_pag_resp *) data;
-	if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n");
-		return -1;
-	}
-
-	/* we need to let it pass for now */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _dt_check_id_resp(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     struct nat_sccp_connection *con,
-			     struct bsc_nat_reject_cause *cause)
-{
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-
-	if (length < 2) {
-		LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n");
-		return -1;
-	}
-
-	if (data[0] < length - 1) {
-		LOGP(DNAT, LOGL_ERROR, "mi length too big.\n");
-		return -2;
-	}
-
-	mi_type = data[1] & GSM_MI_TYPE_MASK;
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]);
-
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	con->imsi_checked = 1;
-	con->imsi = talloc_strdup(con, mi_string);
-	return auth_imsi(bsc, mi_string, cause);
-}
-
-
-/* Filter out CR data... */
-int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
-			struct bsc_nat_parsed *parsed, int *con_type,
-			char **imsi, struct bsc_nat_reject_cause *cause)
-{
-	struct tlv_parsed tp;
-	struct gsm48_hdr *hdr48;
-	int hdr48_len;
-	int len, ret = 0;
-	uint8_t msg_type, proto;
-
-	*con_type = NAT_CON_TYPE_NONE;
-	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-	*imsi = NULL;
-
-	if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "Rejecting CR message due wrong GSM Type %d\n", parsed->gsm_type);
-		return -1;
-	}
-
-	/* the parsed has had some basic l3 length check */
-	len = msg->l3h[1];
-	if (msgb_l3len(msg) - 3 < len) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "The CR Data has not enough space...\n");
-		return -1;
-	}
-
-	msg->l4h = &msg->l3h[3];
-	len -= 1;
-
-	tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h, len, 0, 0);
-
-	if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) {
-		LOGP(DNAT, LOGL_ERROR, "CR Data does not contain layer3 information.\n");
-		return -1;
-	}
-
-	hdr48_len = TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION);
-
-	if (hdr48_len < sizeof(*hdr48)) {
-		LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n");
-		return -1;
-	}
-
-	hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION);
-
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto == GSM48_PDISC_MM &&
-	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
-		*con_type = NAT_CON_TYPE_LU;
-		ret = _cr_check_loc_upd(bsc, &hdr48->data[0],
-					hdr48_len - sizeof(*hdr48), imsi);
-	} else if (proto == GSM48_PDISC_MM &&
-		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
-		*con_type = NAT_CON_TYPE_CM_SERV_REQ;
-		ret = _cr_check_cm_serv_req(bsc, &hdr48->data[0],
-					     hdr48_len - sizeof(*hdr48),
-					     con_type, imsi);
-	} else if (proto == GSM48_PDISC_RR &&
-		   msg_type == GSM48_MT_RR_PAG_RESP) {
-		*con_type = NAT_CON_TYPE_PAG_RESP;
-		ret = _cr_check_pag_resp(bsc, &hdr48->data[0],
-					hdr48_len - sizeof(*hdr48), imsi);
-	} else {
-		/* We only want to filter the above, let other things pass */
-		*con_type = NAT_CON_TYPE_OTHER;
-		return 0;
-	}
-
-	/* check if we are done */
-	if (ret != 1)
-		return ret;
-
-	/* the memory allocation failed */
-	if (!*imsi)
-		return -1;
-
-	/* now check the imsi */
-	return auth_imsi(bsc, *imsi, cause);
-}
-
-int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
-		struct nat_sccp_connection *con, struct bsc_nat_parsed *parsed,
-		struct bsc_nat_reject_cause *cause)
-{
-	uint32_t len;
-	uint8_t msg_type, proto;
-	struct gsm48_hdr *hdr48;
-
-	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-
-	if (con->imsi_checked)
-		return 0;
-
-	/* only care about DTAP messages */
-	if (parsed->bssap != BSSAP_MSG_DTAP)
-		return 0;
-
-	hdr48 = bsc_unpack_dtap(parsed, msg, &len);
-	if (!hdr48)
-		return -1;
-
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP)
-		return 0;
-
-	return _dt_check_id_resp(bsc, &hdr48->data[0],
-					len - sizeof(*hdr48), con, cause);
-}