Commit Graph

3 Commits

Author SHA1 Message Date
Harald Welte c9b46a1c34 Support building with -Werror=strict-prototypes / -Werror=old-style-definition
Unfortunately "-std=c99" is not sufficient to make gcc ignore code that
uses constructs of earlier C standards, which were abandoned in C99.

See https://lwn.net/ml/fedora-devel/Y1kvF35WozzGBpc8@redhat.com/ for
some related discussion.

Change-Id: I79c51b78d1b055361f9ef5434361847353791d0d
2022-11-03 12:42:57 +01:00
Neels Hofmeyr 8b58faa4c2 libosmo-gtlv: add TLIV capability
During code review, it was indicated that some TLV protocols that we
will likely deal with in the near future also employ an I, and instance
value of a tag. Add TLIV support.

A usage example for a manually implemented TLIV structure is found in
tests/libosmo-gtlv/gtlv_test.c.

A usage example for a generated TLIV protocol is found in
tests/libosmo-gtlv/test_tliv/.

Related: SYS#5599
Change-Id: I0a076e54dfba6038cc779cb7c8f3967d212226aa
2022-06-16 13:04:33 +02:00
Neels Hofmeyr 2100097ef1 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
2022-06-16 13:04:33 +02:00