Adding LLC-XID encoder / decoder and unit test

The lle-xid encoder/decoder is needed to encode and decode llc
xid parameter messages. We need this to exchange sndcp-parameters
(SNDCP-XID) and also simple parameters such as encryption IOVs

Change-Id: Ia06e4cb08bf9b48c2a4682606d1b1a91d19a9d37

2 files changed, 58 insertions, 1 deletions

diff --git a/openbsc/include/openbsc/Makefile.am b/openbsc/include/openbsc/Makefile.am
index c272b14de..11f650d12 100644
--- a/openbsc/include/openbsc/Makefile.am
+++ b/openbsc/include/openbsc/Makefile.am
@@ -18,7 +18,7 @@ noinst_HEADERS = abis_nm.h abis_rsl.h db.h gsm_04_08.h gsm_data.h \
 		 gprs_gb_parse.h smpp.h meas_feed.h \
 		 gprs_gsup_client.h bsc_msg_filter.h \
 		 oap.h oap_messages.h \
-		 gtphub.h
+		 gtphub.h gprs_llc_xid.h
 
 openbsc_HEADERS = gsm_04_08.h meas_rep.h bsc_api.h
 openbscdir = $(includedir)/openbsc
diff --git a/openbsc/include/openbsc/gprs_llc_xid.h b/openbsc/include/openbsc/gprs_llc_xid.h
new file mode 100644
index 000000000..d340d40b7
--- /dev/null
+++ b/openbsc/include/openbsc/gprs_llc_xid.h
@@ -0,0 +1,57 @@
+/* GPRS LLC XID field encoding/decoding as per 3GPP TS 44.064 */
+
+/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <osmocom/core/linuxlist.h>
+
+/* 3GPP TS 44.064 6.4.1.6 Exchange Identification (XID)
+   command/response parameter field */
+struct gprs_llc_xid_field {
+	struct llist_head list;
+	uint8_t type;		/* See also Table 6: LLC layer parameter
+				   negotiation */
+	uint8_t *data;		/* Payload data (memory is owned by the
+				 * creator of the struct) */
+	unsigned int data_len;	/* Payload length */
+};
+
+/* Transform a list with XID fields into a XID message (dst) */
+int gprs_llc_compile_xid(uint8_t *dst, int dst_maxlen,
+			 const struct llist_head *xid_fields);
+
+/* Transform a XID message (dst) into a list of XID fields */
+struct llist_head *gprs_llc_parse_xid(const void *ctx, const uint8_t *src,
+				      int src_len);
+
+/* Create a duplicate of an XID-Field */
+struct gprs_llc_xid_field *gprs_llc_dup_xid_field(const void *ctx,
+				const struct gprs_llc_xid_field *xid_field);
+
+/* Copy an llist with xid fields */
+struct llist_head *gprs_llc_copy_xid(const void *ctx,
+				     const struct llist_head *xid_fields);
+
+/* Dump a list with XID fields (Debug) */
+void gprs_llc_dump_xid_fields(const struct llist_head *xid_fields,
+			      unsigned int logl);
+