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.
diff --git a/openbsc/src/osmo-bsc_nat/Makefile.am b/openbsc/src/osmo-bsc_nat/Makefile.am
index ca103a4..7a38430 100644
--- a/openbsc/src/osmo-bsc_nat/Makefile.am
+++ b/openbsc/src/osmo-bsc_nat/Makefile.am
@@ -7,12 +7,13 @@
osmo_bsc_nat_SOURCES = bsc_filter.c bsc_mgcp_utils.c bsc_nat.c bsc_nat_utils.c \
bsc_nat_vty.c bsc_sccp.c bsc_ussd.c bsc_nat_ctrl.c \
- bsc_nat_rewrite.c bsc_nat_filter.c bsc_nat_rewrite_trie.c
+ bsc_nat_rewrite.c bsc_nat_rewrite_trie.c
osmo_bsc_nat_LDADD = \
$(top_builddir)/src/libmgcp/libmgcp.a \
$(top_builddir)/src/libbsc/libbsc.a \
$(top_builddir)/src/libtrau/libtrau.a \
$(top_builddir)/src/libcommon/libcommon.a \
+ $(top_builddir)/src/libfilter/libfilter.a \
-lrt $(LIBOSMOSCCP_LIBS) $(LIBOSMOCORE_LIBS) \
$(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOCTRL_LIBS) \
$(LIBOSMOABIS_LIBS) $(LIBOSMONETIF_LIBS)
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 64f6d73..0000000
--- 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);
-}