Import libgb from openbsc.git

11 files changed, 3814 insertions, 0 deletions

diff --git a/openbsc/src/libgb/Makefile.am b/openbsc/src/libgb/Makefile.am
new file mode 100644
index 00000000..eafbc343
--- /dev/null
+++ b/openbsc/src/libgb/Makefile.am
@@ -0,0 +1,9 @@
+INCLUDES = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
+AM_CFLAGS=-Wall -fno-strict-aliasing $(LIBOSMOCORE_CFLAGS) \
+	$(LIBOSMOVTY_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
+
+noinst_LIBRARIES = libgb.a
+
+libgb_a_SOURCES = gprs_ns.c gprs_ns_frgre.c gprs_ns_vty.c \
+		  gprs_bssgp.c gprs_bssgp_util.c gprs_bssgp_vty.c \
+		  gprs_bssgp_bss.c common_vty.c
diff --git a/openbsc/src/libgb/common_vty.c b/openbsc/src/libgb/common_vty.c
new file mode 100644
index 00000000..0bd0b6c3
--- /dev/null
+++ b/openbsc/src/libgb/common_vty.c
@@ -0,0 +1,90 @@
+/* OpenBSC VTY common helpers */
+/* (C) 2009-2012 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2009-2010 by Holger Hans Peter Freyther
+ * 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 <stdlib.h>
+#include <string.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/vty/telnet_interface.h>
+#include <osmocom/vty/command.h>
+#include <osmocom/vty/buffer.h>
+#include <osmocom/vty/vty.h>
+
+#include <osmocom/gprs/gprs_msgb.h>
+
+#include "common_vty.h"
+
+/* Down vty node level. */
+gDEFUN(libgb_exit,
+       libgb_exit_cmd, "exit", "Exit current mode and down to previous mode\n")
+{
+	switch (vty->node) {
+	case L_NS_NODE:
+	case L_BSSGP_NODE:
+		vty->node = CONFIG_NODE;
+		vty->index = NULL;
+		break;
+	default:
+		break;
+	}
+	return CMD_SUCCESS;
+}
+
+/* End of configuration. */
+gDEFUN(libgb_end,
+       libgb_end_cmd, "end", "End current mode and change to enable mode.")
+{
+	switch (vty->node) {
+	case L_NS_NODE:
+	case L_BSSGP_NODE:
+		vty_config_unlock(vty);
+		vty->node = ENABLE_NODE;
+		vty->index = NULL;
+		vty->index_sub = NULL;
+		break;
+	default:
+		break;
+	}
+	return CMD_SUCCESS;
+}
+
+int gprs_log_filter_fn(const struct log_context *ctx,
+			struct log_target *tar)
+{
+	const struct gprs_nsvc *nsvc = ctx->ctx[GPRS_CTX_NSVC];
+	const struct gprs_bvc *bvc = ctx->ctx[GPRS_CTX_BVC];
+
+	/* Filter on the NS Virtual Connection */
+	if ((tar->filter_map & (1 << FLT_NSVC)) != 0
+	    && nsvc && (nsvc == tar->filter_data[FLT_NSVC]))
+		return 1;
+
+	/* Filter on the NS Virtual Connection */
+	if ((tar->filter_map & (1 << FLT_BVC)) != 0
+	    && bvc && (bvc == tar->filter_data[FLT_BVC]))
+		return 1;
+
+	return 0;
+}
+
+
+int DNS, DBSSGP;
diff --git a/openbsc/src/libgb/common_vty.h b/openbsc/src/libgb/common_vty.h
new file mode 100644
index 00000000..d8d00407
--- /dev/null
+++ b/openbsc/src/libgb/common_vty.h
@@ -0,0 +1,14 @@
+#include <osmocom/vty/command.h>
+#include <osmocom/core/logging.h>
+
+extern int DNS, DBSSGP;
+
+enum log_filter {
+	_FLT_ALL = LOG_FILTER_ALL,	/* libosmocore */
+	FLT_NSVC = 1,
+	FLT_BVC  = 2,
+};
+
+extern struct cmd_element libgb_exit_cmd;
+extern struct cmd_element libgb_end_cmd;
+
diff --git a/openbsc/src/libgb/gprs_bssgp.c b/openbsc/src/libgb/gprs_bssgp.c
new file mode 100644
index 00000000..4b8c7302
--- /dev/null
+++ b/openbsc/src/libgb/gprs_bssgp.c
@@ -0,0 +1,919 @@
+/* GPRS BSSGP protocol implementation as per 3GPP TS 08.18 */
+
+/* (C) 2009-2012 by Harald Welte <laforge@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/>.
+ *
+ * TODO:
+ *  o  properly count incoming BVC-RESET packets in counter group
+ *  o  set log context as early as possible for outgoing packets
+ */
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <netinet/in.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/gsm/tlv.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/rate_ctr.h>
+
+#include <osmocom/gprs/gprs_bssgp.h>
+#include <osmocom/gprs/gprs_ns.h>
+
+#include "common_vty.h"
+
+void *bssgp_tall_ctx = NULL;
+
+static const struct rate_ctr_desc bssgp_ctr_description[] = {
+	{ "packets.in",	"Packets at BSSGP Level ( In)" },
+	{ "packets.out","Packets at BSSGP Level (Out)" },
+	{ "bytes.in",	"Bytes at BSSGP Level   ( In)" },
+	{ "bytes.out",	"Bytes at BSSGP Level   (Out)" },
+	{ "blocked",	"BVC Blocking count" },
+	{ "discarded",	"BVC LLC Discarded count" },
+};
+
+static const struct rate_ctr_group_desc bssgp_ctrg_desc = {
+	.group_name_prefix = "bssgp.bss_ctx",
+	.group_description = "BSSGP Peer Statistics",
+	.num_ctr = ARRAY_SIZE(bssgp_ctr_description),
+	.ctr_desc = bssgp_ctr_description,
+};
+
+LLIST_HEAD(bssgp_bvc_ctxts);
+
+/* Find a BTS Context based on parsed RA ID and Cell ID */
+struct bssgp_bvc_ctx *btsctx_by_raid_cid(const struct gprs_ra_id *raid, uint16_t cid)
+{
+	struct bssgp_bvc_ctx *bctx;
+
+	llist_for_each_entry(bctx, &bssgp_bvc_ctxts, list) {
+		if (!memcmp(&bctx->ra_id, raid, sizeof(bctx->ra_id)) &&
+		    bctx->cell_id == cid)
+			return bctx;
+	}
+	return NULL;
+}
+
+/* Find a BTS context based on BVCI+NSEI tuple */
+struct bssgp_bvc_ctx *btsctx_by_bvci_nsei(uint16_t bvci, uint16_t nsei)
+{
+	struct bssgp_bvc_ctx *bctx;
+
+	llist_for_each_entry(bctx, &bssgp_bvc_ctxts, list) {
+		if (bctx->nsei == nsei && bctx->bvci == bvci)
+			return bctx;
+	}
+	return NULL;
+}
+
+struct bssgp_bvc_ctx *btsctx_alloc(uint16_t bvci, uint16_t nsei)
+{
+	struct bssgp_bvc_ctx *ctx;
+
+	ctx = talloc_zero(bssgp_tall_ctx, struct bssgp_bvc_ctx);
+	if (!ctx)
+		return NULL;
+	ctx->bvci = bvci;
+	ctx->nsei = nsei;
+	/* FIXME: BVCI is not unique, only BVCI+NSEI ?!? */
+	ctx->ctrg = rate_ctr_group_alloc(ctx, &bssgp_ctrg_desc, bvci);
+
+	llist_add(&ctx->list, &bssgp_bvc_ctxts);
+
+	return ctx;
+}
+
+/* Chapter 10.4.5: Flow Control BVC ACK */
+static int bssgp_tx_fc_bvc_ack(uint16_t nsei, uint8_t tag, uint16_t ns_bvci)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = ns_bvci;
+
+	bgph->pdu_type = BSSGP_PDUT_FLOW_CONTROL_BVC_ACK;
+	msgb_tvlv_put(msg, BSSGP_IE_TAG, 1, &tag);
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+/* 10.3.7 SUSPEND-ACK PDU */
+int bssgp_tx_suspend_ack(uint16_t nsei, uint32_t tlli,
+			 const struct gprs_ra_id *ra_id, uint8_t suspend_ref)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	uint32_t _tlli;
+	uint8_t ra[6];
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = 0; /* Signalling */
+	bgph->pdu_type = BSSGP_PDUT_SUSPEND_ACK;
+
+	_tlli = htonl(tlli);
+	msgb_tvlv_put(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &_tlli);
+	gsm48_construct_ra(ra, ra_id);
+	msgb_tvlv_put(msg, BSSGP_IE_ROUTEING_AREA, 6, ra);
+	msgb_tvlv_put(msg, BSSGP_IE_SUSPEND_REF_NR, 1, &suspend_ref);
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+/* 10.3.8 SUSPEND-NACK PDU */
+int bssgp_tx_suspend_nack(uint16_t nsei, uint32_t tlli,
+			  const struct gprs_ra_id *ra_id,
+			  uint8_t *cause)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	uint32_t _tlli;
+	uint8_t ra[6];
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = 0; /* Signalling */
+	bgph->pdu_type = BSSGP_PDUT_SUSPEND_NACK;
+
+	_tlli = htonl(tlli);
+	msgb_tvlv_put(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &_tlli);
+	gsm48_construct_ra(ra, ra_id);
+	msgb_tvlv_put(msg, BSSGP_IE_ROUTEING_AREA, 6, ra);
+	if (cause)
+		msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, cause);
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+/* 10.3.10 RESUME-ACK PDU */
+int bssgp_tx_resume_ack(uint16_t nsei, uint32_t tlli,
+			const struct gprs_ra_id *ra_id)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	uint32_t _tlli;
+	uint8_t ra[6];
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = 0; /* Signalling */
+	bgph->pdu_type = BSSGP_PDUT_RESUME_ACK;
+
+	_tlli = htonl(tlli);
+	msgb_tvlv_put(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &_tlli);
+	gsm48_construct_ra(ra, ra_id);
+	msgb_tvlv_put(msg, BSSGP_IE_ROUTEING_AREA, 6, ra);
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+/* 10.3.11 RESUME-NACK PDU */
+int bssgp_tx_resume_nack(uint16_t nsei, uint32_t tlli,
+			 const struct gprs_ra_id *ra_id, uint8_t *cause)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+		(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	uint32_t _tlli;
+	uint8_t ra[6];
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = 0; /* Signalling */
+	bgph->pdu_type = BSSGP_PDUT_SUSPEND_NACK;
+
+	_tlli = htonl(tlli);
+	msgb_tvlv_put(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &_tlli);
+	gsm48_construct_ra(ra, ra_id);
+	msgb_tvlv_put(msg, BSSGP_IE_ROUTEING_AREA, 6, ra);
+	if (cause)
+		msgb_tvlv_put(msg, BSSGP_IE_CAUSE, 1, cause);
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+uint16_t bssgp_parse_cell_id(struct gprs_ra_id *raid, const uint8_t *buf)
+{
+	/* 6 octets RAC */
+	gsm48_parse_ra(raid, buf);
+	/* 2 octets CID */
+	return ntohs(*(uint16_t *) (buf+6));
+}
+
+int bssgp_create_cell_id(uint8_t *buf, const struct gprs_ra_id *raid,
+			 uint16_t cid)
+{
+	uint16_t *out_cid = (uint16_t *) (buf + 6);
+	/* 6 octets RAC */
+	gsm48_construct_ra(buf, raid);
+	/* 2 octets CID */
+	*out_cid = htons(cid);
+
+	return 8;
+}
+
+/* Chapter 8.4 BVC-Reset Procedure */
+static int bssgp_rx_bvc_reset(struct msgb *msg, struct tlv_parsed *tp,	
+			      uint16_t ns_bvci)
+{
+	struct osmo_bssgp_prim nmp;
+	struct bssgp_bvc_ctx *bctx;
+	uint16_t nsei = msgb_nsei(msg);
+	uint16_t bvci;
+	int rc;
+
+	bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI));
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx RESET cause=%s\n", bvci,
+		bssgp_cause_str(*TLVP_VAL(tp, BSSGP_IE_CAUSE)));
+
+	/* look-up or create the BTS context for this BVC */
+	bctx = btsctx_by_bvci_nsei(bvci, nsei);
+	if (!bctx)
+		bctx = btsctx_alloc(bvci, nsei);
+
+	/* As opposed to NS-VCs, BVCs are NOT blocked after RESET */
+	bctx->state &= ~BVC_S_BLOCKED;
+
+	/* When we receive a BVC-RESET PDU (at least of a PTP BVCI), the BSS
+	 * informs us about its RAC + Cell ID, so we can create a mapping */
+	if (bvci != 0 && bvci != 1) {
+		if (!TLVP_PRESENT(tp, BSSGP_IE_CELL_ID)) {
+			LOGP(DBSSGP, LOGL_ERROR, "BSSGP BVCI=%u Rx RESET "
+				"missing mandatory IE\n", bvci);
+			return -EINVAL;
+		}
+		/* actually extract RAC / CID */
+		bctx->cell_id = bssgp_parse_cell_id(&bctx->ra_id,
+						TLVP_VAL(tp, BSSGP_IE_CELL_ID));
+		LOGP(DBSSGP, LOGL_NOTICE, "Cell %u-%u-%u-%u CI %u on BVCI %u\n",
+			bctx->ra_id.mcc, bctx->ra_id.mnc, bctx->ra_id.lac,
+			bctx->ra_id.rac, bctx->cell_id, bvci);
+	}
+
+	/* Send NM_BVC_RESET.ind to NM */
+	memset(&nmp, 0, sizeof(nmp));
+	nmp.nsei = nsei;
+	nmp.bvci = bvci;
+	nmp.tp = tp;
+	nmp.ra_id = &bctx->ra_id;
+	osmo_prim_init(&nmp.oph, SAP_BSSGP_NM, PRIM_NM_BVC_RESET,
+			PRIM_OP_INDICATION, msg);
+	bssgp_prim_cb(&nmp.oph, NULL);
+
+	/* Acknowledge the RESET to the BTS */
+	rc = bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_RESET_ACK,
+				  nsei, bvci, ns_bvci);
+	return 0;
+}
+
+static int bssgp_rx_bvc_block(struct msgb *msg, struct tlv_parsed *tp)
+{
+	struct osmo_bssgp_prim nmp;
+	uint16_t bvci;
+	struct bssgp_bvc_ctx *ptp_ctx;
+
+	bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI));
+	if (bvci == BVCI_SIGNALLING) {
+		/* 8.3.2: Signalling BVC shall never be blocked */
+		LOGP(DBSSGP, LOGL_ERROR, "NSEI=%u/BVCI=%u "
+			"received block for signalling BVC!?!\n",
+			msgb_nsei(msg), msgb_bvci(msg));
+		return 0;
+	}
+
+	LOGP(DBSSGP, LOGL_INFO, "BSSGP Rx BVCI=%u BVC-BLOCK\n", bvci);
+
+	ptp_ctx = btsctx_by_bvci_nsei(bvci, msgb_nsei(msg));
+	if (!ptp_ctx)
+		return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, &bvci, msg);
+
+	ptp_ctx->state |= BVC_S_BLOCKED;
+	rate_ctr_inc(&ptp_ctx->ctrg->ctr[BSSGP_CTR_BLOCKED]);
+
+	/* Send NM_BVC_BLOCK.ind to NM */
+	memset(&nmp, 0, sizeof(nmp));
+	nmp.nsei = msgb_nsei(msg);
+	nmp.bvci = bvci;
+	nmp.tp = tp;
+	osmo_prim_init(&nmp.oph, SAP_BSSGP_NM, PRIM_NM_BVC_BLOCK,
+			PRIM_OP_INDICATION, msg);
+	bssgp_prim_cb(&nmp.oph, NULL);
+
+	/* We always acknowledge the BLOCKing */
+	return bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_BLOCK_ACK, msgb_nsei(msg),
+				    bvci, msgb_bvci(msg));
+};
+
+static int bssgp_rx_bvc_unblock(struct msgb *msg, struct tlv_parsed *tp)
+{
+	struct osmo_bssgp_prim nmp;
+	uint16_t bvci;
+	struct bssgp_bvc_ctx *ptp_ctx;
+
+	bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI));
+	if (bvci == BVCI_SIGNALLING) {
+		/* 8.3.2: Signalling BVC shall never be blocked */
+		LOGP(DBSSGP, LOGL_ERROR, "NSEI=%u/BVCI=%u "
+			"received unblock for signalling BVC!?!\n",
+			msgb_nsei(msg), msgb_bvci(msg));
+		return 0;
+	}
+
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx BVC-UNBLOCK\n", bvci);
+
+	ptp_ctx = btsctx_by_bvci_nsei(bvci, msgb_nsei(msg));
+	if (!ptp_ctx)
+		return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, &bvci, msg);
+
+	ptp_ctx->state &= ~BVC_S_BLOCKED;
+
+	/* Send NM_BVC_UNBLOCK.ind to NM */
+	memset(&nmp, 0, sizeof(nmp));
+	nmp.nsei = msgb_nsei(msg);
+	nmp.bvci = bvci;
+	nmp.tp = tp;
+	osmo_prim_init(&nmp.oph, SAP_BSSGP_NM, PRIM_NM_BVC_UNBLOCK,
+			PRIM_OP_INDICATION, msg);
+	bssgp_prim_cb(&nmp.oph, NULL);
+
+	/* We always acknowledge the unBLOCKing */
+	return bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_UNBLOCK_ACK, msgb_nsei(msg),
+				    bvci, msgb_bvci(msg));
+};
+
+/* Uplink unit-data */
+static int bssgp_rx_ul_ud(struct msgb *msg, struct tlv_parsed *tp,
+			  struct bssgp_bvc_ctx *ctx)
+{
+	struct osmo_bssgp_prim gbp;
+	struct bssgp_ud_hdr *budh = (struct bssgp_ud_hdr *) msgb_bssgph(msg);
+
+	/* extract TLLI and parse TLV IEs */
+	msgb_tlli(msg) = ntohl(budh->tlli);
+
+	DEBUGP(DBSSGP, "BSSGP TLLI=0x%08x Rx UPLINK-UNITDATA\n", msgb_tlli(msg));
+
+	/* Cell ID and LLC_PDU are the only mandatory IE */
+	if (!TLVP_PRESENT(tp, BSSGP_IE_CELL_ID) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_LLC_PDU)) {
+		LOGP(DBSSGP, LOGL_ERROR, "BSSGP TLLI=0x%08x Rx UL-UD "
+			"missing mandatory IE\n", msgb_tlli(msg));
+		return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
+	}
+
+	/* store pointer to LLC header and CELL ID in msgb->cb */
+	msgb_llch(msg) = (uint8_t *) TLVP_VAL(tp, BSSGP_IE_LLC_PDU);
+	msgb_bcid(msg) = (uint8_t *) TLVP_VAL(tp, BSSGP_IE_CELL_ID);
+
+	/* Send BSSGP_UL_UD.ind to NM */
+	memset(&gbp, 0, sizeof(gbp));
+	gbp.nsei = ctx->nsei;
+	gbp.bvci = ctx->bvci;
+	gbp.tlli = msgb_tlli(msg);
+	gbp.tp = tp;
+	osmo_prim_init(&gbp.oph, SAP_BSSGP_LL, PRIM_BSSGP_UL_UD,
+			PRIM_OP_INDICATION, msg);
+	return bssgp_prim_cb(&gbp.oph, NULL);
+}
+
+static int bssgp_rx_suspend(struct msgb *msg, struct tlv_parsed *tp,
+			    struct bssgp_bvc_ctx *ctx)
+{
+	struct osmo_bssgp_prim gbp;
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
+	struct gprs_ra_id raid;
+	uint32_t tlli;
+	int rc;
+
+	if (!TLVP_PRESENT(tp, BSSGP_IE_TLLI) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_ROUTEING_AREA)) {
+		LOGP(DBSSGP, LOGL_ERROR, "BSSGP BVCI=%u Rx SUSPEND "
+			"missing mandatory IE\n", ctx->bvci);
+		return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
+	}
+
+	tlli = ntohl(*(uint32_t *)TLVP_VAL(tp, BSSGP_IE_TLLI));
+
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u TLLI=0x%08x Rx SUSPEND\n",
+		ctx->bvci, tlli);
+
+	gsm48_parse_ra(&raid, TLVP_VAL(tp, BSSGP_IE_ROUTEING_AREA));
+
+	/* Inform GMM about the SUSPEND request */
+	memset(&gbp, 0, sizeof(gbp));
+	gbp.nsei = msgb_nsei(msg);
+	gbp.bvci = ctx->bvci;
+	gbp.tlli = tlli;
+	gbp.ra_id = &raid;
+	osmo_prim_init(&gbp.oph, SAP_BSSGP_GMM, PRIM_BSSGP_GMM_SUSPEND,
+			PRIM_OP_REQUEST, msg);
+
+	rc = bssgp_prim_cb(&gbp.oph, NULL);
+	if (rc < 0)
+		return bssgp_tx_suspend_nack(msgb_nsei(msg), tlli, &raid, NULL);
+
+	bssgp_tx_suspend_ack(msgb_nsei(msg), tlli, &raid, 0);
+
+	return 0;
+}
+
+static int bssgp_rx_resume(struct msgb *msg, struct tlv_parsed *tp,
+			   struct bssgp_bvc_ctx *ctx)
+{
+	struct osmo_bssgp_prim gbp;
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
+	struct gprs_ra_id raid;
+	uint32_t tlli;
+	uint8_t suspend_ref;
+	int rc;
+
+	if (!TLVP_PRESENT(tp, BSSGP_IE_TLLI) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_ROUTEING_AREA) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_SUSPEND_REF_NR)) {
+		LOGP(DBSSGP, LOGL_ERROR, "BSSGP BVCI=%u Rx RESUME "
+			"missing mandatory IE\n", ctx->bvci);
+		return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
+	}
+
+	tlli = ntohl(*(uint32_t *)TLVP_VAL(tp, BSSGP_IE_TLLI));
+	suspend_ref = *TLVP_VAL(tp, BSSGP_IE_SUSPEND_REF_NR);
+
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u TLLI=0x%08x Rx RESUME\n", ctx->bvci, tlli);
+
+	gsm48_parse_ra(&raid, TLVP_VAL(tp, BSSGP_IE_ROUTEING_AREA));
+
+	/* Inform GMM about the RESUME request */
+	memset(&gbp, 0, sizeof(gbp));
+	gbp.nsei = msgb_nsei(msg);
+	gbp.bvci = ctx->bvci;
+	gbp.tlli = tlli;
+	gbp.ra_id = &raid;
+	gbp.u.resume.suspend_ref = suspend_ref;
+	osmo_prim_init(&gbp.oph, SAP_BSSGP_GMM, PRIM_BSSGP_GMM_RESUME,
+			PRIM_OP_REQUEST, msg);
+
+	rc = bssgp_prim_cb(&gbp.oph, NULL);
+	if (rc < 0)
+		return bssgp_tx_resume_nack(msgb_nsei(msg), tlli, &raid,
+					    NULL);
+
+	bssgp_tx_resume_ack(msgb_nsei(msg), tlli, &raid);
+	return 0;
+}
+
+
+static int bssgp_rx_llc_disc(struct msgb *msg, struct tlv_parsed *tp,
+			     struct bssgp_bvc_ctx *ctx)
+{
+	struct osmo_bssgp_prim nmp;
+	uint32_t tlli = 0;
+
+	if (!TLVP_PRESENT(tp, BSSGP_IE_TLLI) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_LLC_FRAMES_DISCARDED) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_BVCI) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_NUM_OCT_AFF)) {
+		LOGP(DBSSGP, LOGL_ERROR, "BSSGP BVCI=%u Rx LLC DISCARDED "
+			"missing mandatory IE\n", ctx->bvci);
+	}
+
+	if (TLVP_PRESENT(tp, BSSGP_IE_TLLI))
+		tlli = ntohl(*(uint32_t *)TLVP_VAL(tp, BSSGP_IE_TLLI));
+
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u TLLI=%08x Rx LLC DISCARDED\n",
+		ctx->bvci, tlli);
+
+	rate_ctr_inc(&ctx->ctrg->ctr[BSSGP_CTR_DISCARDED]);
+
+	/* send NM_LLC_DISCARDED to NM */
+	memset(&nmp, 0, sizeof(nmp));
+	nmp.nsei = msgb_nsei(msg);
+	nmp.bvci = ctx->bvci;
+	nmp.tlli = tlli;
+	nmp.tp = tp;
+	osmo_prim_init(&nmp.oph, SAP_BSSGP_NM, PRIM_NM_LLC_DISCARDED,
+			PRIM_OP_INDICATION, msg);
+
+	return bssgp_prim_cb(&nmp.oph, NULL);
+}
+
+static int bssgp_rx_fc_bvc(struct msgb *msg, struct tlv_parsed *tp,
+			   struct bssgp_bvc_ctx *bctx)
+{
+
+	DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx Flow Control BVC\n",
+		bctx->bvci);
+
+	if (!TLVP_PRESENT(tp, BSSGP_IE_TAG) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_BVC_BUCKET_SIZE) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_BUCKET_LEAK_RATE) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_BMAX_DEFAULT_MS) ||
+	    !TLVP_PRESENT(tp, BSSGP_IE_R_DEFAULT_MS)) {
+		LOGP(DBSSGP, LOGL_ERROR, "BSSGP BVCI=%u Rx FC BVC "
+			"missing mandatory IE\n", bctx->bvci);
+		return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
+	}
+
+	/* FIXME: actually implement flow control */
+
+	/* Send FLOW_CONTROL_BVC_ACK */
+	return bssgp_tx_fc_bvc_ack(msgb_nsei(msg), *TLVP_VAL(tp, BSSGP_IE_TAG),
+				   msgb_bvci(msg));
+}
+
+/* Receive a BSSGP PDU from a BSS on a PTP BVCI */
+static int bssgp_rx_ptp(struct msgb *msg, struct tlv_parsed *tp,
+			struct bssgp_bvc_ctx *bctx)
+{
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
+	uint8_t pdu_type = bgph->pdu_type;
+	int rc = 0;
+
+	/* If traffic is received on a BVC that is marked as blocked, the
+	 * received PDU shall not be accepted and a STATUS PDU (Cause value:
+	 * BVC Blocked) shall be sent to the peer entity on the signalling BVC */
+	if (bctx->state & BVC_S_BLOCKED && pdu_type != BSSGP_PDUT_STATUS) {
+		uint16_t bvci = msgb_bvci(msg);
+		return bssgp_tx_status(BSSGP_CAUSE_BVCI_BLOCKED, &bvci, msg);
+	}
+
+	switch (pdu_type) {
+	case BSSGP_PDUT_UL_UNITDATA:
+		/* some LLC data from the MS */
+		rc = bssgp_rx_ul_ud(msg, tp, bctx);
+		break;
+	case BSSGP_PDUT_RA_CAPABILITY:
+		/* BSS requests RA capability or IMSI */
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx RA CAPABILITY UPDATE\n",
+			bctx->bvci);
+		/* FIXME: send GMM_RA_CAPABILITY_UPDATE.ind to GMM */
+		/* FIXME: send RA_CAPA_UPDATE_ACK */
+		break;
+	case BSSGP_PDUT_RADIO_STATUS:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx RADIO STATUS\n", bctx->bvci);
+		/* BSS informs us of some exception */
+		/* FIXME: send GMM_RADIO_STATUS.ind to GMM */
+		break;
+	case BSSGP_PDUT_FLOW_CONTROL_BVC:
+		/* BSS informs us of available bandwidth in Gb interface */
+		rc = bssgp_rx_fc_bvc(msg, tp, bctx);
+		break;
+	case BSSGP_PDUT_FLOW_CONTROL_MS:
+		/* BSS informs us of available bandwidth to one MS */
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx Flow Control MS\n",
+			bctx->bvci);
+		/* FIXME: actually implement flow control */
+		/* FIXME: Send FLOW_CONTROL_MS_ACK */
+		break;
+	case BSSGP_PDUT_STATUS:
+		/* Some exception has occurred */
+		/* FIXME: send NM_STATUS.ind to NM */
+	case BSSGP_PDUT_DOWNLOAD_BSS_PFC:
+	case BSSGP_PDUT_CREATE_BSS_PFC_ACK:
+	case BSSGP_PDUT_CREATE_BSS_PFC_NACK:
+	case BSSGP_PDUT_MODIFY_BSS_PFC:
+	case BSSGP_PDUT_DELETE_BSS_PFC_ACK:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx PDU type 0x%02x not [yet] "
+			"implemented\n", bctx->bvci, pdu_type);
+		rc = bssgp_tx_status(BSSGP_CAUSE_PDU_INCOMP_FEAT, NULL, msg);
+		break;
+	/* those only exist in the SGSN -> BSS direction */
+	case BSSGP_PDUT_DL_UNITDATA:
+	case BSSGP_PDUT_PAGING_PS:
+	case BSSGP_PDUT_PAGING_CS:
+	case BSSGP_PDUT_RA_CAPA_UPDATE_ACK:
+	case BSSGP_PDUT_FLOW_CONTROL_BVC_ACK:
+	case BSSGP_PDUT_FLOW_CONTROL_MS_ACK:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u PDU type 0x%02x only exists "
+			"in DL\n", bctx->bvci, pdu_type);
+		bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg);
+		rc = -EINVAL;
+		break;
+	default:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u PDU type 0x%02x unknown\n",
+			bctx->bvci, pdu_type);
+		rc = bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg);
+		break;
+	}
+
+	return rc;
+}
+
+/* Receive a BSSGP PDU from a BSS on a SIGNALLING BVCI */
+static int bssgp_rx_sign(struct msgb *msg, struct tlv_parsed *tp,
+			 struct bssgp_bvc_ctx *bctx)
+{
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
+	uint8_t pdu_type = bgph->pdu_type;
+	int rc = 0;
+	uint16_t ns_bvci = msgb_bvci(msg);
+	uint16_t bvci;
+
+	switch (bgph->pdu_type) {
+	case BSSGP_PDUT_SUSPEND:
+		/* MS wants to suspend */
+		rc = bssgp_rx_suspend(msg, tp, bctx);
+		break;
+	case BSSGP_PDUT_RESUME:
+		/* MS wants to resume */
+		rc = bssgp_rx_resume(msg, tp, bctx);
+		break;
+	case BSSGP_PDUT_FLUSH_LL_ACK:
+		/* BSS informs us it has performed LL FLUSH */
+		DEBUGP(DBSSGP, "BSSGP Rx BVCI=%u FLUSH LL ACK\n", bctx->bvci);
+		/* FIXME: send NM_FLUSH_LL.res to NM */
+		break;
+	case BSSGP_PDUT_LLC_DISCARD:
+		/* BSS informs that some LLC PDU's have been discarded */
+		rc = bssgp_rx_llc_disc(msg, tp, bctx);
+		break;
+	case BSSGP_PDUT_BVC_BLOCK:
+		/* BSS tells us that BVC shall be blocked */
+		if (!TLVP_PRESENT(tp, BSSGP_IE_BVCI) ||
+		    !TLVP_PRESENT(tp, BSSGP_IE_CAUSE)) {
+			LOGP(DBSSGP, LOGL_ERROR, "BSSGP Rx BVC-BLOCK "
+				"missing mandatory IE\n");
+			goto err_mand_ie;
+		}
+		rc = bssgp_rx_bvc_block(msg, tp);
+		break;
+	case BSSGP_PDUT_BVC_UNBLOCK:
+		/* BSS tells us that BVC shall be unblocked */
+		if (!TLVP_PRESENT(tp, BSSGP_IE_BVCI)) {
+			LOGP(DBSSGP, LOGL_ERROR, "BSSGP Rx BVC-UNBLOCK "
+				"missing mandatory IE\n");
+			goto err_mand_ie;
+		}
+		rc = bssgp_rx_bvc_unblock(msg, tp);
+		break;
+	case BSSGP_PDUT_BVC_RESET:
+		/* BSS tells us that BVC init is required */
+		if (!TLVP_PRESENT(tp, BSSGP_IE_BVCI) ||
+		    !TLVP_PRESENT(tp, BSSGP_IE_CAUSE)) {
+			LOGP(DBSSGP, LOGL_ERROR, "BSSGP Rx BVC-RESET "
+				"missing mandatory IE\n");
+			goto err_mand_ie;
+		}
+		rc = bssgp_rx_bvc_reset(msg, tp, ns_bvci);
+		break;
+	case BSSGP_PDUT_STATUS:
+		/* Some exception has occurred */
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx BVC STATUS\n", bctx->bvci);
+		/* FIXME: send NM_STATUS.ind to NM */
+		break;
+	/* those only exist in the SGSN -> BSS direction */
+	case BSSGP_PDUT_PAGING_PS:
+	case BSSGP_PDUT_PAGING_CS:
+	case BSSGP_PDUT_SUSPEND_ACK:
+	case BSSGP_PDUT_SUSPEND_NACK:
+	case BSSGP_PDUT_RESUME_ACK:
+	case BSSGP_PDUT_RESUME_NACK:
+	case BSSGP_PDUT_FLUSH_LL:
+	case BSSGP_PDUT_BVC_BLOCK_ACK:
+	case BSSGP_PDUT_BVC_UNBLOCK_ACK:
+	case BSSGP_PDUT_SGSN_INVOKE_TRACE:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx PDU type 0x%02x only exists "
+			"in DL\n", bctx->bvci, pdu_type);
+		bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg);
+		rc = -EINVAL;
+		break;
+	default:
+		DEBUGP(DBSSGP, "BSSGP BVCI=%u Rx PDU type 0x%02x unknown\n",
+			bctx->bvci, pdu_type);
+		rc = bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg);
+		break;
+	}
+
+	return rc;
+err_mand_ie:
+	return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
+}
+
+/* We expect msgb_bssgph() to point to the BSSGP header */
+int bssgp_rcvmsg(struct msgb *msg)
+{
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_bssgph(msg);
+	struct bssgp_ud_hdr *budh = (struct bssgp_ud_hdr *) msgb_bssgph(msg);
+	struct tlv_parsed tp;
+	struct bssgp_bvc_ctx *bctx;
+	uint8_t pdu_type = bgph->pdu_type;
+	uint16_t ns_bvci = msgb_bvci(msg);
+	int data_len;
+	int rc = 0;
+
+	/* Identifiers from DOWN: NSEI, BVCI (both in msg->cb) */
+
+	/* UNITDATA BSSGP headers have TLLI in front */
+	if (pdu_type != BSSGP_PDUT_UL_UNITDATA &&
+	    pdu_type != BSSGP_PDUT_DL_UNITDATA) {
+		data_len = msgb_bssgp_len(msg) - sizeof(*bgph);
+		rc = bssgp_tlv_parse(&tp, bgph->data, data_len);
+	} else {
+		data_len = msgb_bssgp_len(msg) - sizeof(*budh);
+		rc = bssgp_tlv_parse(&tp, budh->data, data_len);
+	}
+
+	/* look-up or create the BTS context for this BVC */
+	bctx = btsctx_by_bvci_nsei(ns_bvci, msgb_nsei(msg));
+	/* Only a RESET PDU can create a new BVC context */
+	if (!bctx && pdu_type != BSSGP_PDUT_BVC_RESET) {
+		LOGP(DBSSGP, LOGL_NOTICE, "NSEI=%u/BVCI=%u Rejecting PDU "
+			"type %u for unknown BVCI\n", msgb_nsei(msg), ns_bvci,
+			pdu_type);
+		return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, NULL, msg);
+	}
+
+	if (bctx) {
+		log_set_context(GPRS_CTX_BVC, bctx);
+		rate_ctr_inc(&bctx->ctrg->ctr[BSSGP_CTR_PKTS_IN]);
+		rate_ctr_add(&bctx->ctrg->ctr[BSSGP_CTR_BYTES_IN],
+			     msgb_bssgp_len(msg));
+	}
+
+	if (ns_bvci == BVCI_SIGNALLING)
+		rc = bssgp_rx_sign(msg, &tp, bctx);
+	else if (ns_bvci == BVCI_PTM)
+		rc = bssgp_tx_status(BSSGP_CAUSE_PDU_INCOMP_FEAT, NULL, msg);
+	else
+		rc = bssgp_rx_ptp(msg, &tp, bctx);
+
+	return rc;
+}
+
+int bssgp_tx_dl_ud(struct msgb *msg, uint16_t pdu_lifetime,
+		   struct bssgp_dl_ud_par *dup)
+{
+	struct bssgp_bvc_ctx *bctx;
+	struct bssgp_ud_hdr *budh;
+	uint8_t llc_pdu_tlv_hdr_len = 2;
+	uint8_t *llc_pdu_tlv;
+	uint16_t msg_len = msg->len;
+	uint16_t bvci = msgb_bvci(msg);
+	uint16_t nsei = msgb_nsei(msg);
+	uint16_t _pdu_lifetime = htons(pdu_lifetime); /* centi-seconds */
+	uint16_t drx_params;
+
+	/* Identifiers from UP: TLLI, BVCI, NSEI (all in msgb->cb) */
+	if (bvci <= BVCI_PTM ) {
+		LOGP(DBSSGP, LOGL_ERROR, "Cannot send DL-UD to BVCI %u\n",
+			bvci);
+		return -EINVAL;
+	}
+
+	bctx = btsctx_by_bvci_nsei(bvci, nsei);
+	if (!bctx) {
+		/* FIXME: don't simply create missing context, but reject message */
+		bctx = btsctx_alloc(bvci, nsei);
+	}
+
+	if (msg->len > TVLV_MAX_ONEBYTE)
+		llc_pdu_tlv_hdr_len += 1;
+
+	/* prepend the tag and length of the LLC-PDU TLV */
+	llc_pdu_tlv = msgb_push(msg, llc_pdu_tlv_hdr_len);
+	llc_pdu_tlv[0] = BSSGP_IE_LLC_PDU;
+	if (llc_pdu_tlv_hdr_len > 2) {
+		llc_pdu_tlv[1] = msg_len >> 8;
+		llc_pdu_tlv[2] = msg_len & 0xff;
+	} else {
+		llc_pdu_tlv[1] = msg_len & 0x7f;
+		llc_pdu_tlv[1] |= 0x80;
+	}
+
+	/* FIXME: optional elements: Alignment, UTRAN CCO, LSA, PFI */
+
+	if (dup) {
+		/* Old TLLI to help BSS map from old->new */
+		if (dup->tlli) {
+			uint32_t tlli = htonl(*dup->tlli);
+			msgb_tvlv_push(msg, BSSGP_IE_TLLI, 4, (uint8_t *) &tlli);
+		}
+
+		/* IMSI */
+		if (strlen(dup->imsi)) {
+			uint8_t mi[10];
+			int imsi_len = gsm48_generate_mid_from_imsi(mi, dup->imsi);
+			if (imsi_len > 2)
+				msgb_tvlv_push(msg, BSSGP_IE_IMSI,
+						imsi_len-2, mi+2);
+		}
+
+		/* DRX parameters */
+		drx_params = htons(dup->drx_parms);
+		msgb_tvlv_push(msg, BSSGP_IE_DRX_PARAMS, 2,
+				(uint8_t *) &drx_params);
+
+		/* FIXME: Priority */
+
+		/* MS Radio Access Capability */
+		if (dup->ms_ra_cap.len)
+			msgb_tvlv_push(msg, BSSGP_IE_MS_RADIO_ACCESS_CAP,
+					dup->ms_ra_cap.len, dup->ms_ra_cap.v);
+
+	}
+
+	/* prepend the pdu lifetime */
+	msgb_tvlv_push(msg, BSSGP_IE_PDU_LIFETIME, 2, (uint8_t *)&_pdu_lifetime);
+
+	/* prepend the QoS profile, TLLI and pdu type */
+	budh = (struct bssgp_ud_hdr *) msgb_push(msg, sizeof(*budh));
+	memcpy(budh->qos_profile, dup->qos_profile, sizeof(budh->qos_profile));
+	budh->tlli = htonl(msgb_tlli(msg));
+	budh->pdu_type = BSSGP_PDUT_DL_UNITDATA;
+
+	rate_ctr_inc(&bctx->ctrg->ctr[BSSGP_CTR_PKTS_OUT]);
+	rate_ctr_add(&bctx->ctrg->ctr[BSSGP_CTR_BYTES_OUT], msg->len);
+
+	/* Identifiers down: BVCI, NSEI (in msgb->cb) */
+
+	return gprs_ns_sendmsg(bssgp_nsi, msg);
+}
+
+/* Send a single GMM-PAGING.req to a given NSEI/NS-BVCI */
+int bssgp_tx_paging(uint16_t nsei, uint16_t ns_bvci,
+		     struct bssgp_paging_info *pinfo)
+{
+	struct msgb *msg = bssgp_msgb_alloc();
+	struct bssgp_normal_hdr *bgph =
+			(struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph));
+	uint16_t drx_params = htons(pinfo->drx_params);
+	uint8_t mi[10];
+	int imsi_len = gsm48_generate_mid_from_imsi(mi, pinfo->imsi);
+	uint8_t ra[6];
+
+	if (imsi_len < 2)
+		return -EINVAL;
+
+	msgb_nsei(msg) = nsei;
+	msgb_bvci(msg) = ns_bvci;
+
+	if (pinfo->mode == BSSGP_PAGING_PS)
+		bgph->pdu_type = BSSGP_PDUT_PAGING_PS;
+	else
+		bgph->pdu_type = BSSGP_PDUT_PAGING_CS;