diff options
| author | Neels Hofmeyr <neels@hofmeyr.de> | 2018-04-13 03:55:06 +0200 |
|---|---|---|
| committer | Neels Hofmeyr <neels@hofmeyr.de> | 2018-04-18 02:38:37 +0200 |
| commit | 74e4ed6f36d587d9b7d8790cddcd6902b4fe2359 (patch) | |
| tree | a17684f8f7fd0d84e526373b7e5c475ae07bfd51 /include/osmocom/gsm/tlv.h | |
| parent | 8d41d722d605bc3eb2e71daea29bf21ac9031ae3 (diff) | |
tlv: add TLV_GET() and TLV_GET_MINLEN()
Rationale: so far we use code like
if (TLVP_PRESENT(&tp, VERY_LONG_ENUM_VALUE_NAME_THAT_NEVER_ENDS)) {
val = TLVP_VAL(&tp, VERY_LONG_ENUM_VALUE_NAME_THAT_NEVER_ENDS);
len = TLVP_LEN(&tp, VERY_L0NG_ENUM_VALUE_NAME_TH4T_NEVER_EMDS);
}
This is a) very long and b) prone to picking the wrong name one of the three
times, which would use the wrong length or val without necessarily being
noticed. A safer and shorter, more readable pattern is:
struct tlv_p_entry *e = TVLP_GET(&tp, VERY_LONG_ENUM_VALUE_NAME_THAT_NEVER_ENDS);
if (!e)
return -ENOENT;
hexdump(e->val, e->len);
Change-Id: I445de17fc2daa3ab051f5708dd0cc185b23dc048
Diffstat (limited to 'include/osmocom/gsm/tlv.h')
| -rw-r--r-- | include/osmocom/gsm/tlv.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/osmocom/gsm/tlv.h b/include/osmocom/gsm/tlv.h index 996f6aac..a130dc8c 100644 --- a/include/osmocom/gsm/tlv.h +++ b/include/osmocom/gsm/tlv.h @@ -446,6 +446,27 @@ void tlv_def_patch(struct tlv_definition *dst, const struct tlv_definition *src) #define TLVP_PRES_LEN(tp, tag, min_len) \ (TLVP_PRESENT(tp, tag) && TLVP_LEN(tp, tag) >= min_len) +/*! Return pointer to a TLV element if it is present. + * Usage: + * struct tlv_p_entry *e = TVLP_GET(&tp, TAG); + * if (!e) + * return -ENOENT; + * hexdump(e->val, e->len); + * \param[in] _tp pointer to \ref tlv_parsed. + * \param[in] tag IE tag to return. + * \returns struct tlv_p_entry pointer, or NULL if not present. + */ +#define TLVP_GET(_tp, tag) (TLVP_PRESENT(_tp, tag)? &(_tp)->lv[tag] : NULL) + +/*! Like TLVP_GET(), but enforcing a minimum val length. + * \param[in] _tp pointer to \ref tlv_parsed. + * \param[in] tag IE tag to return. + * \param[in] min_len Minimum value length in bytes. + * \returns struct tlv_p_entry pointer, or NULL if not present or too short. + */ +#define TLVP_GET_MINLEN(_tp, tag, min_len) \ + (TLVP_PRES_LEN(_tp, tag, min_len)? &(_tp)->lv[tag] : NULL) + /*! Align given TLV element with 16 bit value to an even address * \param[in] tp pointer to \ref tlv_parsed * \param[in] pos element to return |