From 4ba947bf4b80b553a3411ec1fd29c45430bd6c40 Mon Sep 17 00:00:00 2001 From: Holger Hans Peter Freyther Date: Sun, 5 Apr 2015 18:07:45 +0200 Subject: filter: Separate SCCP/BSSAP extraction and gsm48 code For the BSC we will have the gsm48_hdr and don't need to find data within SCCP. For legacy reasons we need to initialize con_type, imsi, reject causes early on and need to do the same in the filter method. --- openbsc/src/osmo-bsc_nat/Makefile.am | 2 +- openbsc/src/osmo-bsc_nat/bsc_nat_filter.c | 105 ++++++++++++++++++++++++++++++ 2 files changed, 106 insertions(+), 1 deletion(-) create mode 100644 openbsc/src/osmo-bsc_nat/bsc_nat_filter.c (limited to 'openbsc/src/osmo-bsc_nat') diff --git a/openbsc/src/osmo-bsc_nat/Makefile.am b/openbsc/src/osmo-bsc_nat/Makefile.am index 7a38430f9..d96a3911f 100644 --- a/openbsc/src/osmo-bsc_nat/Makefile.am +++ b/openbsc/src/osmo-bsc_nat/Makefile.am @@ -7,7 +7,7 @@ bin_PROGRAMS = osmo-bsc_nat 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_rewrite_trie.c + bsc_nat_rewrite.c bsc_nat_rewrite_trie.c bsc_nat_filter.c osmo_bsc_nat_LDADD = \ $(top_builddir)/src/libmgcp/libmgcp.a \ $(top_builddir)/src/libbsc/libbsc.a \ diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c new file mode 100644 index 000000000..11d370c4c --- /dev/null +++ b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c @@ -0,0 +1,105 @@ +/* + * (C) 2010-2015 by Holger Hans Peter Freyther + * (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 . + * + */ + +#include +#include +#include +#include + +#include + +#include +#include + +#include + +/* 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_filter_reject_cause *cause) +{ + struct tlv_parsed tp; + struct gsm48_hdr *hdr48; + int hdr48_len; + int len; + + *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); + return bsc_msg_filter_initial(hdr48, hdr48_len, bsc, con_type, 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_filter_reject_cause *cause) +{ + uint32_t len; + 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; + + return bsc_msg_filter_data(hdr48, len, bsc, con, cause); +} -- cgit v1.2.3