mirror of https://gerrit.osmocom.org/libosmocore
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
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@ -457,6 +457,12 @@ int tlv_parse2(struct tlv_parsed *dec, int dec_multiples,
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/* take a master (src) tlv def and fill up all empty slots in 'dst' */
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void tlv_def_patch(struct tlv_definition *dst, const struct tlv_definition *src);
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int tlv_encode_one(struct msgb *msg, enum tlv_type type, uint8_t tag,
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unsigned int len, const uint8_t *val);
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int tlv_encode(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp);
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int tlv_encode_ordered(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp,
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const uint8_t *tag_order, unsigned int tag_order_len);
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#define TLVP_PRESENT(x, y) ((x)->lv[y].val)
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#define TLVP_LEN(x, y) (x)->lv[y].len
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#define TLVP_VAL(x, y) (x)->lv[y].val
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@ -537,6 +537,9 @@ tlv_dump;
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tlv_parse;
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tlv_parse2;
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tlv_parse_one;
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tlv_encode;
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tlv_encode_ordered;
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tlv_encode_one;
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tvlv_att_def;
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vtvlv_gan_att_def;
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@ -120,6 +120,103 @@ int osmo_tlvp_merge(struct tlv_parsed *dst, const struct tlv_parsed *src)
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return 0;
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}
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/*! Encode a single TLV into given message buffer
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* \param[inout] msg Caller-allocated message buffer with sufficient tailroom
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* \param[in] type TLV type/format to use during encode
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* \param[in] tag Tag of TLV to be encoded
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* \parma[in] len Length of TLV to be encoded
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* \param[in] val Value part of TLV to be encoded
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* \returns 0 on success; negative in case of error */
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int tlv_encode_one(struct msgb *msg, enum tlv_type type, uint8_t tag,
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unsigned int len, const uint8_t *val)
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{
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switch (type) {
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case TLV_TYPE_NONE:
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break;
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case TLV_TYPE_FIXED:
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msgb_tv_fixed_put(msg, tag, len, val);
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break;
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case TLV_TYPE_T:
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msgb_v_put(msg, tag);
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break;
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case TLV_TYPE_TV:
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msgb_tv_put(msg, tag, val[0]);
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break;
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case TLV_TYPE_TLV:
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msgb_tlv_put(msg, tag, len, val);
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break;
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case TLV_TYPE_TL16V:
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msgb_tl16v_put(msg, tag, len, val);
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break;
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case TLV_TYPE_TvLV:
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msgb_tvlv_put(msg, tag, len, val);
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break;
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case TLV_TYPE_SINGLE_TV:
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msgb_v_put(msg, (tag << 4) | (val[0] & 0xf));
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break;
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case TLV_TYPE_vTvLV_GAN:
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msgb_vtvlv_gan_put(msg, tag, len, val);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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/*! Encode a set of decoded TLVs according to a given definition into a message buffer
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* \param[inout] msg Caller-allocated message buffer with sufficient tailroom
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* \param[in] def structure defining the valid TLV tags / configurations
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* \param[in] tp decoded values to be encoded
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* \returns number of bytes consumed in msg; negative in case of error */
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int tlv_encode(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp)
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{
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unsigned int tailroom_before = msgb_tailroom(msg);
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unsigned int i;
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int rc;
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for (i = 0; i < ARRAY_SIZE(tp->lv); i++) {
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/* skip entries in the array that aren't used/filled */
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if (!TLVP_PRESENT(tp, i))
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continue;
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rc = tlv_encode_one(msg, def->def[i].type, i, TLVP_LEN(tp, i), TLVP_VAL(tp, i));
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if (rc < 0)
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return rc;
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}
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return tailroom_before - msgb_tailroom(msg);
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}
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/*! Encode a set of decoded TLVs according to a given definition and IE order into a message buffer
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* \param[inout] msg Caller-allocated message buffer with sufficient tailroom
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* \param[in] def structure defining the valid TLV tags / configurations
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* \param[in] tp decoded values to be encoded
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* \param[in] tag_order array of tags determining the IE encoding order
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* \param[in] tag_order_len length of tag_order
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* \returns number of bytes consumed in msg; negative in case of error */
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int tlv_encode_ordered(struct msgb *msg, const struct tlv_definition *def, const struct tlv_parsed *tp,
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const uint8_t *tag_order, unsigned int tag_order_len)
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{
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unsigned int tailroom_before = msgb_tailroom(msg);
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unsigned int i;
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int rc;
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for (i = 0; i < tag_order_len; i++) {
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uint8_t tag = tag_order[i];
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/* skip entries in the array that aren't used/filled */
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if (!TLVP_PRESENT(tp, tag))
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continue;
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rc = tlv_encode_one(msg, def->def[tag].type, tag, TLVP_LEN(tp, tag), TLVP_VAL(tp, tag));
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if (rc < 0)
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return rc;
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}
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return tailroom_before - msgb_tailroom(msg);
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}
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/*! Parse a single TLV encoded IE
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* \param[out] o_tag the tag of the IE that was found
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* \param[out] o_len length of the IE that was found
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@ -1,4 +1,6 @@
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#include <osmocom/core/msgb.h>
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#include <osmocom/gsm/tlv.h>
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#include <osmocom/gsm/gsm0808.h>
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static void check_tlv_parse(uint8_t **data, size_t *data_len,
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uint8_t exp_tag, size_t exp_len, const uint8_t *exp_val)
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@ -286,12 +288,57 @@ static void test_tlv_repeated_ie()
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OSMO_ASSERT(dec3[2].lv[tag].val == &test_data[2 + 3 + 3]);
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}
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static void test_tlv_encoder()
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{
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const uint8_t enc_ies[] = {
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0x17, 0x14, 0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
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0x07, 0x08, 0x43, 0x90,
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0x2c, 0x04,
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0x40, 0x42,
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};
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const uint8_t ie_order[] = { 0x2c, 0x40, 0x17 };
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const uint8_t enc_ies_reordered[] = {
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0x2c, 0x04,
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0x40, 0x42,
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0x17, 0x14, 0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
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0x07, 0x08, 0x43, 0x90,
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};
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struct tlv_parsed tp;
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struct msgb *msg = msgb_alloc(1024, __func__);
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int rc;
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printf("Testing TLV encoder by decoding + re-encoding binary\n");
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OSMO_ASSERT(msg);
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/* decode BSSAP IEs specified above */
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rc = osmo_bssap_tlv_parse(&tp, enc_ies, ARRAY_SIZE(enc_ies));
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OSMO_ASSERT(rc == 3);
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/* re-encode it */
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rc = tlv_encode(msg, gsm0808_att_tlvdef(), &tp);
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OSMO_ASSERT(rc == ARRAY_SIZE(enc_ies));
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OSMO_ASSERT(!memcmp(msgb_data(msg), enc_ies, ARRAY_SIZE(enc_ies)));
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msgb_reset(msg);
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printf("Testing TLV encoder with IE ordering\n");
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/* re-encodei in different order */
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rc = tlv_encode_ordered(msg, gsm0808_att_tlvdef(), &tp, ie_order, ARRAY_SIZE(ie_order));
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OSMO_ASSERT(rc == ARRAY_SIZE(enc_ies));
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OSMO_ASSERT(!memcmp(msgb_data(msg), enc_ies_reordered, ARRAY_SIZE(enc_ies_reordered)));
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msgb_free(msg);
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}
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int main(int argc, char **argv)
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{
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//osmo_init_logging2(ctx, &info);
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test_tlv_shift_functions();
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test_tlv_repeated_ie();
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test_tlv_encoder();
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printf("Done.\n");
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return EXIT_SUCCESS;
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@ -1,2 +1,4 @@
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Test shift functions
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Testing TLV encoder by decoding + re-encoding binary
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Testing TLV encoder with IE ordering
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Done.
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