move openbsc/* to repos root

This is the first step in creating this repository from the legacy openbsc.git.

Like all other Osmocom repositories, keep the autoconf and automake files in
the repository root. openbsc.git has been the sole exception, which ends now.

Change-Id: I9c6f2a448d9cb1cc088cf1cf6918b69d7e69b4e7

1 files changed, 251 insertions, 0 deletions

diff --git a/src/gprs/gprs_llc_parse.c b/src/gprs/gprs_llc_parse.c
new file mode 100644
index 000000000..a5a7a7122
--- /dev/null
+++ b/src/gprs/gprs_llc_parse.c
@@ -0,0 +1,251 @@
+/* GPRS LLC protocol implementation as per 3GPP TS 04.64 */
+
+/* (C) 2009-2010 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/>.
+ *
+ */
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/gprs/gprs_bssgp.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/gprs_sgsn.h>
+#include <openbsc/gprs_gmm.h>
+#include <openbsc/gprs_llc.h>
+#include <openbsc/crc24.h>
+
+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 }
+};
+
+#define LLC_ALLOC_SIZE 16384
+#define UI_HDR_LEN	3
+#define N202		4
+#define CRC24_LENGTH	3
+
+int gprs_llc_fcs(uint8_t *data, unsigned int len)
+{
+	uint32_t fcs_calc;
+
+	fcs_calc = crc24_calc(INIT_CRC24, data, len);
+	fcs_calc = ~fcs_calc;
+	fcs_calc &= 0xffffff;
+
+	return fcs_calc;
+}
+
+void gprs_llc_hdr_dump(struct gprs_llc_hdr_parsed *gph, struct gprs_llc_lle *lle)
+{
+	const char *gea;
+	uint32_t iov_ui = 0;
+	if (lle) {
+		gea = get_value_string(gprs_cipher_names, lle->llme->algo);
+		iov_ui = lle->llme->iov_ui;
+	} else
+		gea = "GEA?";
+	DEBUGP(DLLC, "LLC SAPI=%u %c %c %c %s IOV-UI=0x%06x FCS=0x%06x ",
+	       gph->sapi, gph->is_cmd ? 'C' : 'R', gph->ack_req ? 'A' : ' ',
+	       gph->is_encrypted ? 'E' : 'U',
+	       gea, iov_ui, gph->fcs);
+
+	if (gph->cmd)
+		DEBUGPC(DLLC, "CMD=%s ", get_value_string(llc_cmd_strs, gph->cmd));
+
+	if (gph->data)
+		DEBUGPC(DLLC, "DATA ");
+
+	DEBUGPC(DLLC, "\n");
+}
+
+/* parse a GPRS LLC header, also check for invalid frames */
+int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
+		       uint8_t *llc_hdr, int len)
+{
+	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(DLLC, LOGL_NOTICE, "Unsupported SACK frame\n");
+		return -EIO;
+	}
+
+	return 0;
+}