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2.8 KiB

#include <ccan/cast/cast.h>
#include <common/decode_short_channel_ids.h>
#include <common/utils.h>
#include <wire/gen_peer_wire.h>
#include <wire/wire.h>
#include <zlib.h>
static u8 *unzlib(const tal_t *ctx, const u8 *encoded, size_t len)
{
/* http://www.zlib.net/zlib_tech.html gives 1032:1 as worst-case,
* which is 67632120 bytes for us. But they're not encoding zeroes,
* and each scid must be unique. So 1MB is far more reasonable. */
unsigned long unclen = 1024*1024;
int zerr;
u8 *unc = tal_arr(ctx, u8, unclen);
zerr = uncompress(unc, &unclen, encoded, len);
if (zerr != Z_OK)
return tal_free(unc);
/* Truncate and return. */
tal_resize(&unc, unclen);
return unc;
}
struct short_channel_id *decode_short_ids(const tal_t *ctx, const u8 *encoded)
{
struct short_channel_id *scids;
size_t max = tal_count(encoded);
enum scid_encode_types type;
/* BOLT #7:
*
* The receiver:
* - if the first byte of `encoded_short_ids` is not a known encoding
* type:
* - MAY fail the connection
* - if `encoded_short_ids` does not decode into a whole number of
* `short_channel_id`:
* - MAY fail the connection
*/
type = fromwire_u8(&encoded, &max);
switch (type) {
case SHORTIDS_ZLIB:
encoded = unzlib(tmpctx, encoded, max);
if (!encoded)
return NULL;
max = tal_count(encoded);
/* fall thru */
case SHORTIDS_UNCOMPRESSED:
scids = tal_arr(ctx, struct short_channel_id, 0);
while (max) {
struct short_channel_id scid;
fromwire_short_channel_id(&encoded, &max, &scid);
tal_arr_expand(&scids, scid);
}
/* encoded is set to NULL if we ran over */
if (!encoded)
return tal_free(scids);
return scids;
}
return NULL;
}
#if EXPERIMENTAL_FEATURES
bigsize_t *decode_scid_query_flags(const tal_t *ctx,
const struct tlv_query_short_channel_ids_tlvs_query_flags *qf)
{
u8 *encoded = qf->encoded_query_flags;
size_t max = tal_count(encoded);
bigsize_t *flags;
/* BOLT-61a1365a45cc8b463ddbbe3429d350f8eac787dd #7:
*
* The receiver:
*...
* - if the incoming message includes `query_short_channel_ids_tlvs`:
* - if `encoding_type` is not a known encoding type:
* - MAY fail the connection
* - if `encoded_query_flags` does not decode to exactly one flag per
* `short_channel_id`:
* - MAY fail the connection.
*/
switch (qf->encoding_type) {
case SHORTIDS_ZLIB:
encoded = unzlib(tmpctx, encoded, max);
if (!encoded)
return NULL;
max = tal_count(encoded);
/* fall thru */
case SHORTIDS_UNCOMPRESSED:
flags = tal_arr(ctx, bigsize_t, 0);
while (max)
tal_arr_expand(&flags,
fromwire_bigsize(cast_const2(const u8 **,
&encoded),
&max));
/* encoded is set to NULL if we ran over */
if (!encoded)
return tal_free(flags);
return flags;
}
return NULL;
}
#endif /* EXPERIMENTAL_FEATURES */