diff options
Diffstat (limited to 'src/libosmo-gtlv/gtlv_dec_enc.c')
| -rw-r--r-- | src/libosmo-gtlv/gtlv_dec_enc.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/src/libosmo-gtlv/gtlv_dec_enc.c b/src/libosmo-gtlv/gtlv_dec_enc.c index c3e45ea..be3002f 100644 --- a/src/libosmo-gtlv/gtlv_dec_enc.c +++ b/src/libosmo-gtlv/gtlv_dec_enc.c @@ -49,6 +49,19 @@ return RC; \ } while (0) +/* Reverse offsetof(): return the address of the struct member for a given parent struct and member offset value. + * \param parent Pointer to the parent struct, e.g. decoded_struct as passed to osmo_gtlvs_decode(). + * \param parent_size sizeof(*parent), for memory bounds checking, e.g. decoded_struct_size. + * \param memb_ofs byte offset to reach a member (e.g. osmo_gtlv_coding.memb_ofs, .presence_flag_ofs, ...). */ +static const void *membof_const(const void *parent, size_t parent_size, unsigned int memb_ofs) +{ + const uint8_t *p = parent; + const uint8_t *end = p + parent_size; + const uint8_t *memb = p + memb_ofs; + OSMO_ASSERT(memb < end); + OSMO_ASSERT(memb >= p); + return memb; +} /*! Decode a TLV structure from raw data to a decoded struct, for unordered TLV IEs. * How to decode IE values and where to place them in the decoded struct, is defined by ie_coding, an array terminated @@ -378,19 +391,22 @@ int osmo_gtlvs_decode(void *decoded_struct, unsigned int obj_ofs, struct osmo_gt * \param[in] iei_strs value_string array to give IEI names in error messages passed to err_cb(), or NULL. * \return 0 on success, negative on error. */ -int osmo_gtlvs_encode(struct osmo_gtlv_put *gtlv, const void *decoded_struct, unsigned int obj_ofs, - const struct osmo_gtlv_coding *ie_coding, - osmo_gtlv_err_cb err_cb, void *err_cb_data, const struct value_string *iei_strs) +int osmo_gtlvs_encode(struct osmo_gtlv_put *gtlv, const void *decoded_struct, size_t decoded_struct_size, + unsigned int obj_ofs, const struct osmo_gtlv_coding *ie_coding, osmo_gtlv_err_cb err_cb, + void *err_cb_data, const struct value_string *iei_strs) { - void *obj = MEMB(decoded_struct, obj_ofs); + const void *obj = membof_const(decoded_struct, decoded_struct_size, obj_ofs); + size_t obj_maxlen = decoded_struct_size - obj_ofs; if (!ie_coding) return -ENOTSUP; for (; !osmo_gtlv_coding_end(ie_coding); ie_coding++) { int rc; - bool *presence_flag_p = ie_coding->has_presence_flag ? MEMB(obj, ie_coding->presence_flag_ofs) : NULL; - unsigned int *multi_count_p = ie_coding->has_count ? MEMB(obj, ie_coding->count_ofs) : NULL; + const bool *presence_flag_p = ie_coding->has_presence_flag ? + membof_const(obj, obj_maxlen, ie_coding->presence_flag_ofs) : NULL; + const unsigned int *multi_count_p = ie_coding->has_count ? + membof_const(obj, obj_maxlen, ie_coding->count_ofs) : NULL; unsigned int n; unsigned int i; @@ -423,13 +439,14 @@ int osmo_gtlvs_encode(struct osmo_gtlv_put *gtlv, const void *decoded_struct, un .cfg = ie_coding->nested_ies_cfg ? : gtlv->cfg, .dst = gtlv->dst, }; - rc = osmo_gtlvs_encode(&nested_tlv, decoded_struct, obj_ofs + memb_ofs, - ie_coding->nested_ies, err_cb, err_cb_data, iei_strs); + rc = osmo_gtlvs_encode(&nested_tlv, decoded_struct, decoded_struct_size, + obj_ofs + memb_ofs, ie_coding->nested_ies, + err_cb, err_cb_data, iei_strs); if (rc) RETURN_ERROR(rc, ie_coding->ti, "Error while encoding TLV structure nested inside this IE"); } else { - rc = ie_coding->enc_func(gtlv, decoded_struct, MEMB(obj, memb_ofs)); + rc = ie_coding->enc_func(gtlv, decoded_struct, membof_const(obj, obj_maxlen, memb_ofs)); if (rc) RETURN_ERROR(rc, ie_coding->ti, "Error while encoding this IE"); } |