libosmo-gtlv: add generic TLV de- and encoder

An all new TLV parser supporting:

- Any size of T and L (determined by callback function),
- "Grouped IEs", so that an IE payload is a nested IE structure,
- optional/mandatory/multi-occurence IEs,
- decoding unordered tags (or enforcing strict order).

Will be used for PFCP message decoding and encoding, a T16L16V protocol
which requires above features.

Upcoming patches add
- translating PDUs to plain C structs and vice versa
- TLV generator to reduce repetition a in protocol definition
- TLIV capability

Previously, the way we deal with TLVs causes a lot of code
re-implementation: the TL decoding is taken care of by the API, but for
encoding, we essentially re-implement each protocol and each encoded
message in the individual programs. This API is an improvement in that
we only once implement the TL coding (or just use osmo_t8l8v_cfg /
osmo_t16l16v_cfg), get symmetric de- and encoding of the TL, and only
need to deal with the value part of each IE.

The common pattern of
- store TL preliminarily,
- write V data and
- update L after V is complete
is conveniently done by osmo_gtlv_put_update_tl().

Related: SYS#5599
Change-Id: Ib0fd00d9f288ffe13b7e67701f3e47073587404a

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/libosmo-gtlv/Makefile.am b/tests/libosmo-gtlv/Makefile.am
new file mode 100644
index 0000000..7ab4ae0
--- /dev/null
+++ b/tests/libosmo-gtlv/Makefile.am
@@ -0,0 +1,30 @@
+AM_CPPFLAGS = \
+	$(all_includes) \
+	-I$(top_srcdir)/include \
+	$(NULL)
+
+AM_CFLAGS = \
+	-Wall \
+	$(LIBOSMOCORE_CFLAGS) \
+	$(NULL)
+
+noinst_PROGRAMS = \
+	gtlv_test \
+	$(NULL)
+
+EXTRA_DIST = \
+	gtlv_test.ok \
+	$(NULL)
+
+gtlv_test_SOURCES = \
+	gtlv_test.c \
+	$(NULL)
+
+gtlv_test_LDADD = \
+	$(top_builddir)/src/libosmo-gtlv/libosmo-gtlv.a \
+	$(LIBOSMOCORE_LIBS) \
+	$(NULL)
+
+.PHONY: update_exp
+update_exp:
+	$(builddir)/gtlv_test >$(srcdir)/gtlv_test.ok