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authorHarald Welte <laforge@gnumonks.org>2019-02-13 22:23:13 +0100
committerHarald Welte <laforge@gnumonks.org>2019-05-19 07:33:32 +0000
commit8006f5393e21750558a01c780641831d925382ee (patch)
tree7cb67ca98a93395015075d540613dcc46a356e9e
parente0c5d700ae4289cf1f4f5fae1d061b666387cb3d (diff)
TLV: Add one-shot TLV encoder
So far, the TLV code contained two types of functions * tlp_parse() to parse all TLVs according to definition into tlvp_parsed * various helper functions to encode individual TLVs during message generation This patch implements the inverse of tlv_parse(): tlv_encode(), which takes a full 'struct tlv_pared' and encodes all IEs found in it. The order of IEs is in numerically ascending order of the tag. As many protocols have different IE/TLV ordering requirements, let's add a tlv_encode_ordered() function where the caller can specify the TLV ordering during the one-shot encode. Change-Id: I761a30bf20355a9f80a4a8e0c60b0b0f78515efe
-rw-r--r--include/osmocom/gsm/tlv.h6
-rw-r--r--src/gsm/libosmogsm.map3
-rw-r--r--src/gsm/tlv_parser.c97
-rw-r--r--tests/tlv/tlv_test.c47
-rw-r--r--tests/tlv/tlv_test.ok2
5 files changed, 155 insertions, 0 deletions
diff --git a/include/osmocom/gsm/tlv.h b/include/osmocom/gsm/tlv.h
index d0c9552..bb0e8fc 100644
--- a/include/osmocom/gsm/tlv.h
+++ b/include/osmocom/gsm/tlv.h
@@ -457,6 +457,12 @@ int tlv_parse2(struct tlv_parsed *dec, int dec_multiples,
/* take a master (src) tlv def and fill up all empty slots in 'dst' */
void tlv_def_patch(struct tlv_definition *dst, const struct tlv_definition *src);
+int tlv_encode_one(struct msgb *msg, enum tlv_type type, uint8_t tag,
+ unsigned int len, const uint8_t *val);
+int tlv_encode(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp);
+int tlv_encode_ordered(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp,
+ const uint8_t *tag_order, unsigned int tag_order_len);
+
#define TLVP_PRESENT(x, y) ((x)->lv[y].val)
#define TLVP_LEN(x, y) (x)->lv[y].len
#define TLVP_VAL(x, y) (x)->lv[y].val
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 0f4a0db..299504e 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -537,6 +537,9 @@ tlv_dump;
tlv_parse;
tlv_parse2;
tlv_parse_one;
+tlv_encode;
+tlv_encode_ordered;
+tlv_encode_one;
tvlv_att_def;
vtvlv_gan_att_def;
diff --git a/src/gsm/tlv_parser.c b/src/gsm/tlv_parser.c
index 6e089f7..159b42b 100644
--- a/src/gsm/tlv_parser.c
+++ b/src/gsm/tlv_parser.c
@@ -120,6 +120,103 @@ int osmo_tlvp_merge(struct tlv_parsed *dst, const struct tlv_parsed *src)
return 0;
}
+
+/*! Encode a single TLV into given message buffer
+ * \param[inout] msg Caller-allocated message buffer with sufficient tailroom
+ * \param[in] type TLV type/format to use during encode
+ * \param[in] tag Tag of TLV to be encoded
+ * \parma[in] len Length of TLV to be encoded
+ * \param[in] val Value part of TLV to be encoded
+ * \returns 0 on success; negative in case of error */
+int tlv_encode_one(struct msgb *msg, enum tlv_type type, uint8_t tag,
+ unsigned int len, const uint8_t *val)
+{
+ switch (type) {
+ case TLV_TYPE_NONE:
+ break;
+ case TLV_TYPE_FIXED:
+ msgb_tv_fixed_put(msg, tag, len, val);
+ break;
+ case TLV_TYPE_T:
+ msgb_v_put(msg, tag);
+ break;
+ case TLV_TYPE_TV:
+ msgb_tv_put(msg, tag, val[0]);
+ break;
+ case TLV_TYPE_TLV:
+ msgb_tlv_put(msg, tag, len, val);
+ break;
+ case TLV_TYPE_TL16V:
+ msgb_tl16v_put(msg, tag, len, val);
+ break;
+ case TLV_TYPE_TvLV:
+ msgb_tvlv_put(msg, tag, len, val);
+ break;
+ case TLV_TYPE_SINGLE_TV:
+ msgb_v_put(msg, (tag << 4) | (val[0] & 0xf));
+ break;
+ case TLV_TYPE_vTvLV_GAN:
+ msgb_vtvlv_gan_put(msg, tag, len, val);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/*! Encode a set of decoded TLVs according to a given definition into a message buffer
+ * \param[inout] msg Caller-allocated message buffer with sufficient tailroom
+ * \param[in] def structure defining the valid TLV tags / configurations
+ * \param[in] tp decoded values to be encoded
+ * \returns number of bytes consumed in msg; negative in case of error */
+int tlv_encode(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp)
+{
+ unsigned int tailroom_before = msgb_tailroom(msg);
+ unsigned int i;
+ int rc;
+
+ for (i = 0; i < ARRAY_SIZE(tp->lv); i++) {
+ /* skip entries in the array that aren't used/filled */
+ if (!TLVP_PRESENT(tp, i))
+ continue;
+
+ rc = tlv_encode_one(msg, def->def[i].type, i, TLVP_LEN(tp, i), TLVP_VAL(tp, i));
+ if (rc < 0)
+ return rc;
+ }
+
+ return tailroom_before - msgb_tailroom(msg);
+}
+
+/*! Encode a set of decoded TLVs according to a given definition and IE order into a message buffer
+ * \param[inout] msg Caller-allocated message buffer with sufficient tailroom
+ * \param[in] def structure defining the valid TLV tags / configurations
+ * \param[in] tp decoded values to be encoded
+ * \param[in] tag_order array of tags determining the IE encoding order
+ * \param[in] tag_order_len length of tag_order
+ * \returns number of bytes consumed in msg; negative in case of error */
+int tlv_encode_ordered(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp,
+ const uint8_t *tag_order, unsigned int tag_order_len)
+{
+
+ unsigned int tailroom_before = msgb_tailroom(msg);
+ unsigned int i;
+ int rc;
+
+ for (i = 0; i < tag_order_len; i++) {
+ uint8_t tag = tag_order[i];
+
+ /* skip entries in the array that aren't used/filled */
+ if (!TLVP_PRESENT(tp, tag))
+ continue;
+
+ rc = tlv_encode_one(msg, def->def[tag].type, tag, TLVP_LEN(tp, tag), TLVP_VAL(tp, tag));
+ if (rc < 0)
+ return rc;
+ }
+ return tailroom_before - msgb_tailroom(msg);
+}
+
/*! Parse a single TLV encoded IE
* \param[out] o_tag the tag of the IE that was found
* \param[out] o_len length of the IE that was found
diff --git a/tests/tlv/tlv_test.c b/tests/tlv/tlv_test.c
index e2065b0..925d762 100644
--- a/tests/tlv/tlv_test.c
+++ b/tests/tlv/tlv_test.c
@@ -1,4 +1,6 @@
+#include <osmocom/core/msgb.h>
#include <osmocom/gsm/tlv.h>
+#include <osmocom/gsm/gsm0808.h>
static void check_tlv_parse(uint8_t **data, size_t *data_len,
uint8_t exp_tag, size_t exp_len, const uint8_t *exp_val)
@@ -286,12 +288,57 @@ static void test_tlv_repeated_ie()
OSMO_ASSERT(dec3[2].lv[tag].val == &test_data[2 + 3 + 3]);
}
+static void test_tlv_encoder()
+{
+ const uint8_t enc_ies[] = {
+ 0x17, 0x14, 0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
+ 0x07, 0x08, 0x43, 0x90,
+ 0x2c, 0x04,
+ 0x40, 0x42,
+ };
+ const uint8_t ie_order[] = { 0x2c, 0x40, 0x17 };
+ const uint8_t enc_ies_reordered[] = {
+ 0x2c, 0x04,
+ 0x40, 0x42,
+ 0x17, 0x14, 0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
+ 0x07, 0x08, 0x43, 0x90,
+ };
+ struct tlv_parsed tp;
+ struct msgb *msg = msgb_alloc(1024, __func__);
+ int rc;
+
+ printf("Testing TLV encoder by decoding + re-encoding binary\n");
+
+ OSMO_ASSERT(msg);
+
+ /* decode BSSAP IEs specified above */
+ rc = osmo_bssap_tlv_parse(&tp, enc_ies, ARRAY_SIZE(enc_ies));
+ OSMO_ASSERT(rc == 3);
+
+ /* re-encode it */
+ rc = tlv_encode(msg, gsm0808_att_tlvdef(), &tp);
+ OSMO_ASSERT(rc == ARRAY_SIZE(enc_ies));
+ OSMO_ASSERT(!memcmp(msgb_data(msg), enc_ies, ARRAY_SIZE(enc_ies)));
+
+ msgb_reset(msg);
+
+ printf("Testing TLV encoder with IE ordering\n");
+
+ /* re-encodei in different order */
+ rc = tlv_encode_ordered(msg, gsm0808_att_tlvdef(), &tp, ie_order, ARRAY_SIZE(ie_order));
+ OSMO_ASSERT(rc == ARRAY_SIZE(enc_ies));
+ OSMO_ASSERT(!memcmp(msgb_data(msg), enc_ies_reordered, ARRAY_SIZE(enc_ies_reordered)));
+
+ msgb_free(msg);
+}
+
int main(int argc, char **argv)
{
//osmo_init_logging2(ctx, &info);
test_tlv_shift_functions();
test_tlv_repeated_ie();
+ test_tlv_encoder();
printf("Done.\n");
return EXIT_SUCCESS;
diff --git a/tests/tlv/tlv_test.ok b/tests/tlv/tlv_test.ok
index de159bf..f3f0fd4 100644
--- a/tests/tlv/tlv_test.ok
+++ b/tests/tlv/tlv_test.ok
@@ -1,2 +1,4 @@
Test shift functions
+Testing TLV encoder by decoding + re-encoding binary
+Testing TLV encoder with IE ordering
Done.