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lightningd: encode fallback address in 5 bits

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The bolt11 specification requires that the version number of the
Fallback on-chain address should be 5 bits wide instead of 8
bits.
This commit is contained in:
John Barboza 2018-02-14 18:41:22 -05:00 • committed by Rusty Russell
parent c4590b6e60
commit 7a77271922
1 changed files with 23 additions and 21 deletions
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44
common/bolt11.c
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@ -777,6 +777,23 @@ static void push_varlen_field(u5 **data, char type, u64 val)
abort();
}
/* BOLT #11:
*
* The fallback field is of format:
*
* 1. `type` (5 bits)
* 2. `data_length` (10 bits, big-endian)
* 3. `version` (5 bits)
* 4. `data` (addr_len * 8 bits)
*/
static void push_fallback_addr(u5 **data, u5 version, const void *addr, u16 addr_len)
{
push_varlen_uint(data, bech32_charset_rev[(unsigned char)'f'], 5);
push_varlen_uint(data, ((5 + addr_len * CHAR_BIT) + 4) / 5, 10);
push_varlen_uint(data, version, 5);
push_bits(data, addr, addr_len * CHAR_BIT);
}
static void encode_p(u5 **data, const struct sha256 *hash)
{
push_field(data, 'p', hash, 256);
@ -823,34 +840,19 @@ static void encode_f(u5 **data, const u8 *fallback)
* or `18` followed by a script hash.
*/
if (is_p2pkh(fallback, &pkh)) {
u8 v17[1 + sizeof(pkh)];
v17[0] = 17;
memcpy(v17+1, &pkh, sizeof(pkh));
push_field(data, 'f', v17, sizeof(v17) * CHAR_BIT);
push_fallback_addr(data, 17, &pkh, sizeof(pkh));
} else if (is_p2sh(fallback, &sh)) {
u8 v18[1 + sizeof(sh)];
v18[0] = 18;
memcpy(v18+1, &sh, sizeof(sh));
push_field(data, 'f', v18, sizeof(v18) * CHAR_BIT);
push_fallback_addr(data, 18, &sh, sizeof(sh));
} else if (is_p2wpkh(fallback, &pkh)) {
u8 v0[1 + sizeof(pkh)];
v0[0] = 0;
memcpy(v0+1, &pkh, sizeof(pkh));
push_field(data, 'f', v0, sizeof(v0) * CHAR_BIT);
push_fallback_addr(data, 0, &pkh, sizeof(pkh));
} else if (is_p2wsh(fallback, &wsh)) {
u8 v0[1 + sizeof(wsh)];
v0[0] = 0;
memcpy(v0+1, &wsh, sizeof(wsh));
push_field(data, 'f', v0, sizeof(v0) * CHAR_BIT);
push_fallback_addr(data, 0, &wsh, sizeof(wsh));
} else if (tal_len(fallback)
&& fallback[0] >= 0x50
&& fallback[0] < (0x50+16)) {
/* Other (future) witness versions: turn OP_N into N */
u8 *f = tal_dup_arr(NULL, u8,
fallback, tal_len(fallback), 0);
f[0] -= 0x50;
push_field(data, 'f', f, tal_len(f) * CHAR_BIT);
tal_free(f);
push_fallback_addr(data, fallback[0] - 0x50, fallback + 1,
tal_len(fallback) - 1);
} else {
/* Copy raw. */
push_field(data, 'f',