This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/osmocom-net-gprs@lists.osmocom.org/.
Holger Freyther hfreyther at sysmocom.deFrom: Holger Hans Peter Freyther <holger at moiji-mobile.com>
Use the OpenBSC SGSN code to parse the LLC data and look into
the data we receive. Add assertions to verify the the sequence
number is increasing.
---
tests/Makefile.am | 3 +-
tests/emu/openbsc_clone.c | 216 ++++++++++++++++++++++++++++++++++
tests/emu/openbsc_clone.h | 64 ++++++++++
tests/emu/pcu_emu.cpp | 7 ++
tests/emu/test_replay_gprs_attach.cpp | 39 ++++++
5 files changed, 328 insertions(+), 1 deletion(-)
create mode 100644 tests/emu/openbsc_clone.c
create mode 100644 tests/emu/openbsc_clone.h
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 7216d3b..0131e47 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -9,7 +9,8 @@ rlcmac_RLCMACTest_LDADD = \
$(LIBOSMOCORE_LIBS) \
$(COMMON_LA)
-emu_pcu_emu_SOURCES = emu/pcu_emu.cpp emu/test_replay_gprs_attach.cpp
+emu_pcu_emu_SOURCES = emu/pcu_emu.cpp emu/test_replay_gprs_attach.cpp \
+ emu/openbsc_clone.c emu/openbsc_clone.h
emu_pcu_emu_LDADD = \
$(top_builddir)/src/libgprs.la \
$(LIBOSMOGB_LIBS) \
diff --git a/tests/emu/openbsc_clone.c b/tests/emu/openbsc_clone.c
new file mode 100644
index 0000000..707819b
--- /dev/null
+++ b/tests/emu/openbsc_clone.c
@@ -0,0 +1,216 @@
+/* (C) 2009-2010 by Harald Welte <laforge at gnumonks.org>
+ *
+ * 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_clone.h"
+
+#include <gprs_debug.h>
+
+#include <osmocom/core/utils.h>
+
+#include <errno.h>
+
+/* Section 6.4 Commands and Responses */
+enum gprs_llc_u_cmd {
+ GPRS_LLC_U_DM_RESP = 0x01,
+ GPRS_LLC_U_DISC_CMD = 0x04,
+ GPRS_LLC_U_UA_RESP = 0x06,
+ GPRS_LLC_U_SABM_CMD = 0x07,
+ GPRS_LLC_U_FRMR_RESP = 0x08,
+ GPRS_LLC_U_XID = 0x0b,
+ GPRS_LLC_U_NULL_CMD = 0x00,
+};
+
+#define LLC_ALLOC_SIZE 16384
+#define UI_HDR_LEN 3
+#define N202 4
+#define CRC24_LENGTH 3
+
+static const struct value_string llc_cmd_strs[] = {
+ { GPRS_LLC_NULL, "NULL" },
+ { GPRS_LLC_RR, "RR" },
+ { GPRS_LLC_ACK, "ACK" },
+ { GPRS_LLC_RNR, "RNR" },
+ { GPRS_LLC_SACK, "SACK" },
+ { GPRS_LLC_DM, "DM" },
+ { GPRS_LLC_DISC, "DISC" },
+ { GPRS_LLC_UA, "UA" },
+ { GPRS_LLC_SABM, "SABM" },
+ { GPRS_LLC_FRMR, "FRMR" },
+ { GPRS_LLC_XID, "XID" },
+ { GPRS_LLC_UI, "UI" },
+ { 0, NULL }
+};
+
+int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
+ const uint8_t *llc_hdr, int len)
+{
+ const uint8_t *ctrl = llc_hdr+1;
+
+ if (len <= CRC24_LENGTH)
+ return -EIO;
+
+ ghp->crc_length = len - CRC24_LENGTH;
+
+ ghp->ack_req = 0;
+
+ /* Section 5.5: FCS */
+ ghp->fcs = *(llc_hdr + len - 3);
+ ghp->fcs |= *(llc_hdr + len - 2) << 8;
+ ghp->fcs |= *(llc_hdr + len - 1) << 16;
+
+ /* Section 6.2.1: invalid PD field */
+ if (llc_hdr[0] & 0x80)
+ return -EIO;
+
+ /* This only works for the MS->SGSN direction */
+ if (llc_hdr[0] & 0x40)
+ ghp->is_cmd = 0;
+ else
+ ghp->is_cmd = 1;
+
+ ghp->sapi = llc_hdr[0] & 0xf;
+
+ /* Section 6.2.3: check for reserved SAPI */
+ switch (ghp->sapi) {
+ case 0:
+ case 4:
+ case 6:
+ case 0xa:
+ case 0xc:
+ case 0xd:
+ case 0xf:
+ return -EINVAL;
+ }
+
+ if ((ctrl[0] & 0x80) == 0) {
+ /* I (Information transfer + Supervisory) format */
+ uint8_t k;
+
+ ghp->data = ctrl + 3;
+
+ if (ctrl[0] & 0x40)
+ ghp->ack_req = 1;
+
+ ghp->seq_tx = (ctrl[0] & 0x1f) << 4;
+ ghp->seq_tx |= (ctrl[1] >> 4);
+
+ ghp->seq_rx = (ctrl[1] & 0x7) << 6;
+ ghp->seq_rx |= (ctrl[2] >> 2);
+
+ switch (ctrl[2] & 0x03) {
+ case 0:
+ ghp->cmd = GPRS_LLC_RR;
+ break;
+ case 1:
+ ghp->cmd = GPRS_LLC_ACK;
+ break;
+ case 2:
+ ghp->cmd = GPRS_LLC_RNR;
+ break;
+ case 3:
+ ghp->cmd = GPRS_LLC_SACK;
+ k = ctrl[3] & 0x1f;
+ ghp->data += 1 + k;
+ break;
+ }
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+ } else if ((ctrl[0] & 0xc0) == 0x80) {
+ /* S (Supervisory) format */
+ ghp->data = NULL;
+ ghp->data_len = 0;
+
+ if (ctrl[0] & 0x20)
+ ghp->ack_req = 1;
+ ghp->seq_rx = (ctrl[0] & 0x7) << 6;
+ ghp->seq_rx |= (ctrl[1] >> 2);
+
+ switch (ctrl[1] & 0x03) {
+ case 0:
+ ghp->cmd = GPRS_LLC_RR;
+ break;
+ case 1:
+ ghp->cmd = GPRS_LLC_ACK;
+ break;
+ case 2:
+ ghp->cmd = GPRS_LLC_RNR;
+ break;
+ case 3:
+ ghp->cmd = GPRS_LLC_SACK;
+ break;
+ }
+ } else if ((ctrl[0] & 0xe0) == 0xc0) {
+ /* UI (Unconfirmed Inforamtion) format */
+ ghp->cmd = GPRS_LLC_UI;
+ ghp->data = ctrl + 2;
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+
+ ghp->seq_tx = (ctrl[0] & 0x7) << 6;
+ ghp->seq_tx |= (ctrl[1] >> 2);
+ if (ctrl[1] & 0x02) {
+ ghp->is_encrypted = 1;
+ /* FIXME: encryption */
+ }
+ if (ctrl[1] & 0x01) {
+ /* FCS over hdr + all inf fields */
+ } else {
+ /* FCS over hdr + N202 octets (4) */
+ if (ghp->crc_length > UI_HDR_LEN + N202)
+ ghp->crc_length = UI_HDR_LEN + N202;
+ }
+ } else {
+ /* U (Unnumbered) format: 1 1 1 P/F M4 M3 M2 M1 */
+ ghp->data = NULL;
+ ghp->data_len = 0;
+
+ switch (ctrl[0] & 0xf) {
+ case GPRS_LLC_U_NULL_CMD:
+ ghp->cmd = GPRS_LLC_NULL;
+ break;
+ case GPRS_LLC_U_DM_RESP:
+ ghp->cmd = GPRS_LLC_DM;
+ break;
+ case GPRS_LLC_U_DISC_CMD:
+ ghp->cmd = GPRS_LLC_DISC;
+ break;
+ case GPRS_LLC_U_UA_RESP:
+ ghp->cmd = GPRS_LLC_UA;
+ break;
+ case GPRS_LLC_U_SABM_CMD:
+ ghp->cmd = GPRS_LLC_SABM;
+ break;
+ case GPRS_LLC_U_FRMR_RESP:
+ ghp->cmd = GPRS_LLC_FRMR;
+ break;
+ case GPRS_LLC_U_XID:
+ ghp->cmd = GPRS_LLC_XID;
+ ghp->data = ctrl + 1;
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+ break;
+ default:
+ return -EIO;
+ }
+ }
+
+ /* FIXME: parse sack frame */
+ if (ghp->cmd == GPRS_LLC_SACK) {
+ LOGP(DPCU, LOGL_NOTICE, "Unsupported SACK frame\n");
+ return -EIO;
+ }
+
+ return 0;
+}
diff --git a/tests/emu/openbsc_clone.h b/tests/emu/openbsc_clone.h
new file mode 100644
index 0000000..d62ff22
--- /dev/null
+++ b/tests/emu/openbsc_clone.h
@@ -0,0 +1,64 @@
+/* (C) 2009-2010 by Harald Welte <laforge at gnumonks.org>
+ *
+ * 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/>.
+ *
+ */
+#ifndef OPENBSC_CLONE_H
+#define OPENBSC_CLONE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+enum gprs_llc_cmd {
+ GPRS_LLC_NULL,
+ GPRS_LLC_RR,
+ GPRS_LLC_ACK,
+ GPRS_LLC_RNR,
+ GPRS_LLC_SACK,
+ GPRS_LLC_DM,
+ GPRS_LLC_DISC,
+ GPRS_LLC_UA,
+ GPRS_LLC_SABM,
+ GPRS_LLC_FRMR,
+ GPRS_LLC_XID,
+ GPRS_LLC_UI,
+};
+
+struct gprs_llc_hdr_parsed {
+ uint8_t sapi;
+ uint8_t is_cmd:1,
+ ack_req:1,
+ is_encrypted:1;
+ uint32_t seq_rx;
+ uint32_t seq_tx;
+ uint32_t fcs;
+ uint32_t fcs_calc;
+ const uint8_t *data;
+ uint16_t data_len;
+ uint16_t crc_length;
+ enum gprs_llc_cmd cmd;
+};
+
+int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp, const uint8_t *llc_hdr, int len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/tests/emu/pcu_emu.cpp b/tests/emu/pcu_emu.cpp
index 337c0c8..f4d38cd 100644
--- a/tests/emu/pcu_emu.cpp
+++ b/tests/emu/pcu_emu.cpp
@@ -37,6 +37,7 @@ struct gprs_rlcmac_bts *gprs_rlcmac_bts;
int16_t spoof_mnc = 0, spoof_mcc = 0;
extern void test_replay_gprs_attach(struct gprs_bssgp_pcu *pcu);
+extern void test_replay_gprs_data(struct gprs_bssgp_pcu *, struct msgb *, struct tlv_parsed *);
struct gprs_rlcmac_bts *create_bts()
{
@@ -70,6 +71,11 @@ static void bvci_unblocked(struct gprs_bssgp_pcu *pcu)
test_replay_gprs_attach(pcu);
}
+static void bssgp_data(struct gprs_bssgp_pcu *pcu, struct msgb *msg, struct tlv_parsed *tp)
+{
+ test_replay_gprs_data(pcu, msg, tp);
+}
+
void create_and_connect_bssgp(struct gprs_rlcmac_bts *bts,
uint32_t sgsn_ip, uint16_t sgsn_port)
{
@@ -78,6 +84,7 @@ void create_and_connect_bssgp(struct gprs_rlcmac_bts *bts,
pcu = gprs_bssgp_create_and_connect(bts, 0, sgsn_ip, sgsn_port,
20, 20, 20, 0x901, 0x99, 1, 0, 0);
pcu->on_unblock_ack = bvci_unblocked;
+ pcu->on_dl_unit_data = bssgp_data;
}
int main(int argc, char **argv)
diff --git a/tests/emu/test_replay_gprs_attach.cpp b/tests/emu/test_replay_gprs_attach.cpp
index 500b16e..fb1e77f 100644
--- a/tests/emu/test_replay_gprs_attach.cpp
+++ b/tests/emu/test_replay_gprs_attach.cpp
@@ -19,13 +19,18 @@
extern "C" {
#include <osmocom/core/msgb.h>
+#include <osmocom/core/backtrace.h>
+#include <osmocom/gsm/gsm_utils.h>
}
+#include "openbsc_clone.h"
+
#include <gprs_bssgp_pcu.h>
#include <stdint.h>
#include <string.h>
+/* GPRS attach with a foreign TLLI */
static const uint8_t gprs_attach_llc[] = {
/* LLC-PDU IE */
0x0e, 0x00, 0x2e,
@@ -38,6 +43,8 @@ static const uint8_t gprs_attach_llc[] = {
0x42, 0x00, 0x40, 0xaa, 0xf3, 0x18
};
+static int next_wanted_nu;
+
struct msgb *create_msg(const uint8_t *data, size_t len)
{
struct msgb *msg = msgb_alloc_headroom(4096, 128, "create msg");
@@ -51,6 +58,38 @@ void test_replay_gprs_attach(struct gprs_bssgp_pcu *pcu)
uint32_t tlli = 0xadf11820;
const uint8_t qos_profile[] = { 0x0, 0x0, 0x04 };
+ next_wanted_nu = 0;
struct msgb *msg = create_msg(gprs_attach_llc, ARRAY_SIZE(gprs_attach_llc));
bssgp_tx_ul_ud(pcu->bctx, tlli, qos_profile, msg);
}
+
+void test_replay_gprs_data(struct gprs_bssgp_pcu *pcu, struct msgb *msg, struct tlv_parsed *tp)
+{
+ struct bssgp_ud_hdr *budh;
+ struct gprs_llc_hdr_parsed ph;
+ uint32_t tlli;
+
+ if (!TLVP_PRESENT(tp, BSSGP_IE_LLC_PDU))
+ return;
+
+
+ gprs_llc_hdr_parse(&ph, TLVP_VAL(tp, BSSGP_IE_LLC_PDU),
+ TLVP_LEN(tp, BSSGP_IE_LLC_PDU));
+
+ budh = (struct bssgp_ud_hdr *)msgb_bssgph(msg);
+ tlli = ntohl(budh->tlli);
+
+ /* all messages we should get, should be for a foreign tlli */
+ OSMO_ASSERT(gprs_tlli_type(tlli) == TLLI_FOREIGN);
+ printf("TLLI(0x%08x) is foreign!\n", tlli);
+
+ OSMO_ASSERT(ph.cmd == GPRS_LLC_UI);
+ OSMO_ASSERT(ph.sapi == 1);
+ OSMO_ASSERT(ph.seq_tx == next_wanted_nu++);
+
+ /* this test just wants to see messages... no further data is sent */
+ if (next_wanted_nu == 4) {
+ printf("Test done.\n");
+ exit(EXIT_SUCCESS);
+ }
+}
--
1.8.3.2