63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
#include <common/decode_short_channel_ids.h>
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#include <common/utils.h>
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#include <wire/wire.h>
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#include <zlib.h>
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static u8 *unzlib(const tal_t *ctx, const u8 *encoded, size_t len)
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{
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/* http://www.zlib.net/zlib_tech.html gives 1032:1 as worst-case,
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* which is 67632120 bytes for us. But they're not encoding zeroes,
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* and each scid must be unique. So 1MB is far more reasonable. */
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unsigned long unclen = 1024*1024;
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int zerr;
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u8 *unc = tal_arr(ctx, u8, unclen);
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zerr = uncompress(unc, &unclen, encoded, len);
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if (zerr != Z_OK)
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return tal_free(unc);
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/* Truncate and return. */
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tal_resize(&unc, unclen);
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return unc;
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}
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struct short_channel_id *decode_short_ids(const tal_t *ctx, const u8 *encoded)
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{
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struct short_channel_id *scids;
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size_t max = tal_count(encoded);
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enum scid_encode_types type;
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/* BOLT #7:
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*
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* The receiver:
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* - if the first byte of `encoded_short_ids` is not a known encoding
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* type:
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* - MAY fail the connection
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* - if `encoded_short_ids` does not decode into a whole number of
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* `short_channel_id`:
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* - MAY fail the connection
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*/
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type = fromwire_u8(&encoded, &max);
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switch (type) {
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case SHORTIDS_ZLIB:
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encoded = unzlib(tmpctx, encoded, max);
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if (!encoded)
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return NULL;
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max = tal_count(encoded);
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/* fall thru */
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case SHORTIDS_UNCOMPRESSED:
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scids = tal_arr(ctx, struct short_channel_id, 0);
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while (max) {
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struct short_channel_id scid;
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fromwire_short_channel_id(&encoded, &max, &scid);
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tal_arr_expand(&scids, scid);
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}
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/* encoded is set to NULL if we ran over */
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if (!encoded)
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return tal_free(scids);
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return scids;
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}
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return NULL;
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}
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