diff options
| author | Harald Welte <laforge@gnumonks.org> | 2018-02-02 12:11:14 +0100 |
|---|---|---|
| committer | Harald Welte <laforge@gnumonks.org> | 2018-02-09 02:02:42 +0100 |
| commit | bf383a1d83661af26ccd6521c49b655fb22531d4 (patch) | |
| tree | 0c6b88cee3b62c59d30aa668e15a725b32df1b38 | |
| parent | 6de34ee46b1d256e98d0048c5407f0eec929288b (diff) | |
tlv_parser: Report *first* occurrence of repeated IEs
Most GSM related specifications require the receiver to use the
*first* occurrence of repeated IEs. The Osmocom TLV parser so
far did the opposite: It reported only the *last* occurrence in
case of repeated IEs. Let's change our implementation to be
more in-line with relevant specs, such as 3GPP TS 24.008 8.6.3.
Change-Id: Icde09e075f68c842a7a96cf7160c8e44b77cf82d
| -rw-r--r-- | src/gsm/tlv_parser.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/gsm/tlv_parser.c b/src/gsm/tlv_parser.c index 9b1fb17a..b8c7149f 100644 --- a/src/gsm/tlv_parser.c +++ b/src/gsm/tlv_parser.c @@ -276,8 +276,13 @@ int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, &buf[ofs], buf_len-ofs); if (rv < 0) return rv; - dec->lv[tag].val = val; - dec->lv[tag].len = len; + /* Most GSM related protocols clearly indicate that in case of duplicate + * IEs, only the first occurrence shall be used, while any further occurrences + * shall be ignored. See e.g. 3GPP TS 24.008 Section 8.6.3 */ + if (dec->lv[tag].val == NULL) { + dec->lv[tag].val = val; + dec->lv[tag].len = len; + } ofs += rv; num_parsed++; } |