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rgb-cln/common/bolt11.c

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#include "config.h"
#include <assert.h>
#include <bitcoin/address.h>
#include <bitcoin/script.h>
#include <ccan/array_size/array_size.h>
#include <ccan/tal/str/str.h>
#include <common/bech32.h>
#include <common/bech32_util.h>
#include <common/bolt11.h>
#include <common/features.h>
#include <errno.h>
#include <inttypes.h>
#include <lightningd/lightningd.h>
bool dev_bolt11_old_order;
bool dev_bolt11_omit_c_value;
struct multiplier {
const char letter;
/* We can't represent p postfix to msat, so we multiply this by 10 */
u64 m10;
};
/* BOLT #11:
*
* The following `multiplier` letters are defined:
*
* * `m` (milli): multiply by 0.001
* * `u` (micro): multiply by 0.000001
* * `n` (nano): multiply by 0.000000001
* * `p` (pico): multiply by 0.000000000001
*/
static struct multiplier multipliers[] = {
{ 'm', 10 * MSAT_PER_BTC / 1000 },
{ 'u', 10 * MSAT_PER_BTC / 1000000 },
{ 'n', 10 * MSAT_PER_BTC / 1000000000 },
{ 'p', 10 * MSAT_PER_BTC / 1000000000000ULL }
};
/* If pad is false, we discard any bits which don't fit in the last byte.
* Otherwise we add an extra byte. Returns error string or NULL on success. */
static const char *pull_bits(struct hash_u5 *hu5,
const u5 **data, size_t *data_len,
void *dst, size_t nbits,
bool pad)
{
size_t n5 = nbits / 5;
size_t len = 0;
if (nbits % 5)
n5++;
if (*data_len < n5)
return "truncated";
if (!bech32_convert_bits(dst, &len, 8, *data, n5, 5, pad))
return "non-zero trailing bits";
if (hu5)
hash_u5(hu5, *data, n5);
*data += n5;
*data_len -= n5;
return NULL;
}
/* Helper for pulling a variable-length big-endian int. */
static const char *pull_uint(struct hash_u5 *hu5,
const u5 **data, size_t *data_len,
u64 *val, size_t databits)
{
be64 be_val;
const char *err;
/* Too big. */
if (databits > sizeof(be_val) * CHAR_BIT)
return "integer too large";
err = pull_bits(hu5, data, data_len, &be_val, databits, true);
if (err)
return err;
if (databits == 0)
*val = 0;
else
*val = be64_to_cpu(be_val) >>
(sizeof(be_val) * CHAR_BIT - databits);
return NULL;
}
static void *pull_all(const tal_t *ctx,
struct hash_u5 *hu5,
const u5 **data, size_t *data_len,
bool pad,
const char **err)
{
void *ret;
size_t retlen;
if (pad)
retlen = (*data_len * 5 + 7) / 8;
else
retlen = (*data_len * 5) / 8;
ret = tal_arr(ctx, u8, retlen);
*err = pull_bits(hu5, data, data_len, ret, *data_len * 5, pad);
if (*err)
return tal_free(ret);
return ret;
}
/* Frees bolt11, returns NULL. */
static struct bolt11 *decode_fail(struct bolt11 *b11, char **fail,
const char *fmt, ...)
PRINTF_FMT(3,4);
static struct bolt11 *decode_fail(struct bolt11 *b11, char **fail,
const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
*fail = tal_vfmt(tal_parent(b11), fmt, ap);
va_end(ap);
return tal_free(b11);
}
/*
* These handle specific fields in the payment request; returning the problem
* if any, or NULL.
*/
static const char *unknown_field(struct bolt11 *b11,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
u5 type)
{
struct bolt11_field *extra = tal(b11, struct bolt11_field);
const char *err;
extra->tag = type;
/* FIXME: record u8 data here, not u5! */
extra->data = tal_dup_arr(extra, u5, *data, *field_len, 0);
list_add_tail(&b11->extra_fields, &extra->list);
tal_free(pull_all(extra, hu5, data, field_len, true, &err));
return err;
}
/* If field isn't expected length (in *bech32*!), call unknown_field.
* Otherwise copy into dst without padding, set have_flag if non-NULL. */
static const char *pull_expected_length(struct bolt11 *b11,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
size_t expected_length,
u5 type,
bool *have_flag,
void *dst)
{
if (*field_len != expected_length)
return unknown_field(b11, hu5, data, field_len, type);
if (have_flag)
*have_flag = true;
return pull_bits(hu5, data, field_len, dst, *field_len * 5, false);
}
/* BOLT #11:
*
* `p` (1): `data_length` 52. 256-bit SHA256 payment_hash. Preimage of this
* provides proof of payment
*/
static const char *decode_p(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_p)
{
/* BOLT #11:
*
* A payer... SHOULD use the first `p` field that it did NOT
* skip as the payment hash.
*/
assert(!*have_p);
/* BOLT #11:
*
* A reader... MUST skip over unknown fields, OR an `f` field
* with unknown `version`, OR `p`, `h`, `s` or `n` fields that do
* NOT have `data_length`s of 52, 52, 52 or 53, respectively.
*/
return pull_expected_length(b11, hu5, data, field_len, 52, 'p',
have_p, &b11->payment_hash);
}
/* BOLT #11:
*
* `d` (13): `data_length` variable. Short description of purpose of payment
* (UTF-8), e.g. '1 cup of coffee' or 'ナンセンス 1杯'
*/
static const char *decode_d(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_d)
{
u8 *desc;
const char *err;
assert(!*have_d);
desc = pull_all(NULL, hu5, data, field_len, false, &err);
if (!desc)
return err;
*have_d = true;
b11->description = utf8_str(b11, take(desc), tal_bytelen(desc));
if (b11->description)
return NULL;
return tal_fmt(b11, "d: invalid utf8");
}
/* BOLT #11:
*
* `h` (23): `data_length` 52. 256-bit description of purpose of payment
* (SHA256). This is used to commit to an associated description that is over
* 639 bytes, but the transport mechanism for the description in that case is
* transport specific and not defined here.
*/
static const char *decode_h(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_h)
{
const char *err;
struct sha256 hash;
assert(!*have_h);
/* BOLT #11:
*
* A reader... MUST skip over unknown fields, OR an `f` field
* with unknown `version`, OR `p`, `h`, `s` or `n` fields that do
* NOT have `data_length`s of 52, 52, 52 or 53, respectively. */
err = pull_expected_length(b11, hu5, data, field_len, 52, 'h',
have_h, &hash);
/* If that gave us the hash, store it */
if (*have_h)
b11->description_hash = tal_dup(b11, struct sha256, &hash);
return err;
}
/* BOLT #11:
*
* `x` (6): `data_length` variable. `expiry` time in seconds
* (big-endian). Default is 3600 (1 hour) if not specified.
*/
#define DEFAULT_X 3600
static const char *decode_x(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_x)
{
const char *err;
assert(!*have_x);
/* FIXME: Put upper limit in bolt 11 */
err = pull_uint(hu5, data, field_len, &b11->expiry, *field_len * 5);
if (err)
return tal_fmt(b11, "x: %s", err);
*have_x = true;
return NULL;
}
/* BOLT #11:
*
* `c` (24): `data_length` variable. `min_final_cltv_expiry_delta` to use for the
* last HTLC in the route. Default is 18 if not specified.
*/
static const char *decode_c(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_c)
{
u64 c;
const char *err;
assert(!*have_c);
/* FIXME: Put upper limit in bolt 11 */
err = pull_uint(hu5, data, field_len, &c, *field_len * 5);
if (err)
return tal_fmt(b11, "c: %s", err);
b11->min_final_cltv_expiry = c;
/* Can overflow, since c is 64 bits but value must be < 32 bits */
if (b11->min_final_cltv_expiry != c)
return tal_fmt(b11, "c: %"PRIu64" is too large", c);
*have_c = true;
return NULL;
}
static const char *decode_n(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_n)
{
const char *err;
assert(!*have_n);
/* BOLT #11:
*
* A reader... MUST skip over unknown fields, OR an `f` field
* with unknown `version`, OR `p`, `h`, `s` or `n` fields that do
* NOT have `data_length`s of 52, 52, 52 or 53, respectively. */
err = pull_expected_length(b11, hu5, data, field_len, 53, 'n', have_n,
&b11->receiver_id.k);
/* If that gave us a node ID, check it. */
if (*have_n) {
struct pubkey k;
if (!pubkey_from_node_id(&k, &b11->receiver_id))
return tal_fmt(
b11, "invalid public key %s",
node_id_to_hexstr(tmpctx, &b11->receiver_id));
}
return err;
}
/* BOLT #11:
*
* * `s` (16): `data_length` 52. This 256-bit secret prevents
* forwarding nodes from probing the payment recipient.
*/
static const char *decode_s(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_s)
{
const char *err;
struct secret secret;
assert(!*have_s);
/* BOLT #11:
*
* A reader... MUST skip over unknown fields, OR an `f` field
* with unknown `version`, OR `p`, `h`, `s` or `n` fields that do
* NOT have `data_length`s of 52, 52, 52 or 53, respectively. */
err = pull_expected_length(b11, hu5, data, field_len, 52, 's',
have_s, &secret);
if (*have_s)
b11->payment_secret = tal_dup(b11, struct secret, &secret);
return err;
}
/* BOLT #11:
*
* `f` (9): `data_length` variable, depending on version. Fallback
* on-chain address: for Bitcoin, this starts with a 5-bit `version`
* and contains a witness program or P2PKH or P2SH address.
*/
static const char *decode_f(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_f)
{
u64 version;
u8 *fallback;
const u5 *orig_data = *data;
size_t orig_len = *field_len;
const char *err;
err = pull_uint(hu5, data, field_len, &version, 5);
if (err)
return tal_fmt(b11, "f: %s", err);
/* BOLT #11:
*
* for Bitcoin payments... MUST set an `f` field to a valid
* witness version and program, OR to `17` followed by a
* public key hash, OR to `18` followed by a script hash.
*/
if (version == 17) {
/* Pay to pubkey hash (P2PKH) */
struct bitcoin_address *pkhash;
pkhash = pull_all(tmpctx, hu5, data, field_len, false, &err);
if (!pkhash)
return err;
if (tal_bytelen(pkhash) != sizeof(*pkhash))
return tal_fmt(b11, "f: pkhash length %zu",
tal_bytelen(pkhash));
fallback = scriptpubkey_p2pkh(b11, pkhash);
} else if (version == 18) {
/* Pay to pubkey script hash (P2SH) */
struct ripemd160 *shash;
shash = pull_all(tmpctx, hu5, data, field_len, false, &err);
if (!shash)
return err;
if (tal_bytelen(shash) != sizeof(*shash))
return tal_fmt(b11, "f: p2sh length %zu",
tal_bytelen(shash));
fallback = scriptpubkey_p2sh_hash(b11, shash);
} else if (version < 17) {
u8 *f = pull_all(tmpctx, hu5, data, field_len, false, &err);
if (!f)
return err;
if (version == 0) {
if (tal_count(f) != 20 && tal_count(f) != 32)
return tal_fmt(b11,
"f: witness v0 bad length %zu",
tal_count(f));
}
if (version == 1 && tal_count(f) != 32) {
return tal_fmt(b11,
"f: witness v1 bad length %zu",
tal_count(f));
}
if (tal_count(f) > 40) {
return tal_fmt(b11,
"f: witness v%"PRIu64" bad length %zu",
version,
tal_count(f));
}
fallback = scriptpubkey_witness_raw(b11, version,
f, tal_count(f));
} else {
/* Restore version for unknown field! */
*data = orig_data;
*field_len = orig_len;
return unknown_field(b11, hu5, data, field_len, 'f');
}
if (b11->fallbacks == NULL)
b11->fallbacks = tal_arr(b11, const u8 *, 1);
else
tal_resize(&b11->fallbacks, tal_count(b11->fallbacks) + 1);
b11->fallbacks[tal_count(b11->fallbacks)-1]
= tal_steal(b11->fallbacks, fallback);
*have_f = true;
return NULL;
}
static bool fromwire_route_info(const u8 **cursor, size_t *max,
struct route_info *route_info)
{
fromwire_node_id(cursor, max, &route_info->pubkey);
fromwire_short_channel_id(cursor, max, &route_info->short_channel_id);
route_info->fee_base_msat = fromwire_u32(cursor, max);
route_info->fee_proportional_millionths = fromwire_u32(cursor, max);
route_info->cltv_expiry_delta = fromwire_u16(cursor, max);
return *cursor != NULL;
}
static void towire_route_info(u8 **pptr, const struct route_info *route_info)
{
towire_node_id(pptr, &route_info->pubkey);
towire_short_channel_id(pptr, &route_info->short_channel_id);
towire_u32(pptr, route_info->fee_base_msat);
towire_u32(pptr, route_info->fee_proportional_millionths);
towire_u16(pptr, route_info->cltv_expiry_delta);
}
/* BOLT #11:
*
* `r` (3): `data_length` variable. One or more entries containing
* extra routing information for a private route; there may be more
* than one `r` field
*
* * `pubkey` (264 bits)
* * `short_channel_id` (64 bits)
* * `fee_base_msat` (32 bits, big-endian)
* * `fee_proportional_millionths` (32 bits, big-endian)
* * `cltv_expiry_delta` (16 bits, big-endian)
*/
static const char *decode_r(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_r)
{
const u8 *r8;
size_t n = 0;
struct route_info *r = tal_arr(b11->routes, struct route_info, n);
const char *err;
size_t rlen;
/* Route hops don't split in 5 bit boundaries, so convert whole thing */
r8 = pull_all(tmpctx, hu5, data, field_len, false, &err);
if (!r8)
return err;
rlen = tal_bytelen(r8);
do {
struct route_info ri;
if (!fromwire_route_info(&r8, &rlen, &ri)) {
return tal_fmt(b11, "r: hop %zu truncated", n);
}
tal_arr_expand(&r, ri);
} while (rlen);
/* Append route */
tal_arr_expand(&b11->routes, r);
*have_r = true;
return NULL;
}
static void shift_bitmap_down(u8 *bitmap, size_t bits)
{
u8 prev = 0;
assert(bits < CHAR_BIT);
for (size_t i = 0; i < tal_bytelen(bitmap); i++) {
/* Save top bits for next one */
u8 v = bitmap[i];
bitmap[i] = (prev | (v >> bits));
prev = (v << (8 - bits));
}
assert(prev == 0);
}
/* BOLT #11:
*
* `9` (5): `data_length` variable. One or more 5-bit values containing features
* supported or required for receiving this payment.
* See [Feature Bits](#feature-bits).
*/
static const char *decode_9(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_9)
{
size_t flen = (*field_len * 5 + 7) / 8;
int badf;
size_t databits = *field_len * 5;
const char *err;
assert(!*have_9);
b11->features = pull_all(b11, hu5, data, field_len, true, &err);
if (!b11->features)
return err;
/* pull_bits pads with zero bits: we need to remove them. */
shift_bitmap_down(b11->features,
flen * 8 - databits);
/* BOLT #11:
*
* - if the `9` field contains unknown _odd_ bits that are non-zero:
* - MUST ignore the bit.
* - if the `9` field contains unknown _even_ bits that are non-zero:
* - MUST fail the payment.
*/
/* We skip this check for the cli tool, which sets our_features to NULL */
if (our_features) {
badf = features_unsupported(our_features,
b11->features, BOLT11_FEATURE);
if (badf != -1)
return tal_fmt(b11, "9: unknown feature bit %i", badf);
}
*have_9 = true;
return NULL;
}
/* BOLT #11:
*
* `m` (27): `data_length` variable. Additional metadata to attach to
* the payment. Note that the size of this field is limited by the
* maximum hop payload size. Long metadata fields reduce the maximum
* route length.
*/
static const char *decode_m(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_m)
{
const char *err;
assert(!*have_m);
b11->metadata = pull_all(b11, hu5, data, field_len, false, &err);
if (!b11->metadata)
return err;
*have_m = true;
return NULL;
}
struct bolt11 *new_bolt11(const tal_t *ctx,
const struct amount_msat *msat TAKES)
{
struct bolt11 *b11 = tal(ctx, struct bolt11);
list_head_init(&b11->extra_fields);
b11->description = NULL;
b11->description_hash = NULL;
b11->fallbacks = NULL;
b11->routes = NULL;
b11->msat = NULL;
b11->expiry = DEFAULT_X;
b11->features = tal_arr(b11, u8, 0);
/* BOLT #11:
* - if the `c` field (`min_final_cltv_expiry_delta`) is not provided:
* - MUST use an expiry delta of at least 18 when making the payment
*/
b11->min_final_cltv_expiry = 18;
b11->payment_secret = NULL;
b11->metadata = NULL;
if (msat)
b11->msat = tal_dup(b11, struct amount_msat, msat);
return b11;
}
struct decoder {
/* What BOLT11 letter this is */
const char letter;
/* If false, then any dups get treated as "unknown" fields */
bool allow_duplicates;
/* Routine to decode: returns NULL if it decodes ok, and
* sets *have_field = true if it is not an unknown form.
* Otherwise returns error string (literal or tal off b11). */
const char *(*decode)(struct bolt11 *b11,
const struct feature_set *our_features,
struct hash_u5 *hu5,
const u5 **data, size_t *field_len,
bool *have_field);
};
static const struct decoder decoders[] = {
/* BOLT #11:
*
* A payer... SHOULD use the first `p` field that it did NOT
* skip as the payment hash.
*/
{ 'p', false, decode_p },
{ 'd', false, decode_d },
{ 'h', false, decode_h },
{ 'x', false, decode_x },
{ 'c', false, decode_c },
{ 'n', false, decode_n },
{ 's', false, decode_s },
/* BOLT #11:
* - MAY include one or more `f` fields.
*/
{ 'f', true, decode_f },
/* BOLT #11:
*
* there may be more than one `r` field
*/
{ 'r', true, decode_r },
{ '9', false, decode_9 },
{ 'm', false, decode_m },
};
static const struct decoder *find_decoder(char c)
{
for (size_t i = 0; i < ARRAY_SIZE(decoders); i++) {
if (decoders[i].letter == c)
return decoders + i;
}
return NULL;
}
static bool bech32_decode_alloc(const tal_t *ctx,
const char **hrp_ret,
const u5 **data_ret,
size_t *data_len,
const char *str)
{
char *hrp = tal_arr(ctx, char, strlen(str) - 6);
u5 *data = tal_arr(ctx, u5, strlen(str) - 8);
if (bech32_decode(hrp, data, data_len, str, (size_t)-1)
!= BECH32_ENCODING_BECH32) {
tal_free(hrp);
tal_free(data);
return false;
}
/* We needed temporaries because these are const */
*hrp_ret = hrp;
*data_ret = data;
return true;
}
static bool has_lightning_prefix(const char *invstring)
{
/* BOLT #11:
*
* If a URI scheme is desired, the current recommendation is to either
* use 'lightning:' as a prefix before the BOLT-11 encoding */
return (strstarts(invstring, "lightning:") ||
strstarts(invstring, "LIGHTNING:"));
}
const char *to_canonical_invstr(const tal_t *ctx,
const char *invstring)
{
if (has_lightning_prefix(invstring))
invstring += strlen("lightning:");
return str_lowering(ctx, invstring);
}
/* Extracts signature but does not check it. */
struct bolt11 *bolt11_decode_nosig(const tal_t *ctx, const char *str,
const struct feature_set *our_features,
const char *description,
const struct chainparams *must_be_chain,
struct sha256 *hash,
const u5 **sig,
bool *have_n,
char **fail)
{
const char *hrp, *prefix;
char *amountstr;
const u5 *data;
size_t data_len;
struct bolt11 *b11 = new_bolt11(ctx, NULL);
struct hash_u5 hu5;
const char *err;
/* We don't need all of these, but in theory we could have 32 types */
bool have_field[32];
memset(have_field, 0, sizeof(have_field));
b11->routes = tal_arr(b11, struct route_info *, 0);
if (strlen(str) < 8)
return decode_fail(b11, fail, "Bad bech32 string");
if (!bech32_decode_alloc(tmpctx, &hrp, &data, &data_len, str))
return decode_fail(b11, fail, "Bad bech32 string");
/* For signature checking at the end. */
hash_u5_init(&hu5, hrp);
/* BOLT #11:
*
* The human-readable part of a Lightning invoice consists of two sections:
* 1. `prefix`: `ln` + BIP-0173 currency prefix (e.g. `lnbc` for Bitcoin mainnet,
* `lntb` for Bitcoin testnet, `lntbs` for Bitcoin signet, and `lnbcrt` for Bitcoin regtest)
* 1. `amount`: optional number in that currency, followed by an optional
* `multiplier` letter. The unit encoded here is the 'social' convention of a payment unit -- in the case of Bitcoin the unit is 'bitcoin' NOT satoshis.
*/
prefix = tal_strndup(tmpctx, hrp, strcspn(hrp, "0123456789"));
/* BOLT #11:
*
* A reader...if it does NOT understand the `prefix`... MUST fail the payment.
*/
if (!strstarts(prefix, "ln"))
return decode_fail(b11, fail,
"Prefix '%s' does not start with ln", prefix);
if (must_be_chain) {
if (streq(prefix + 2, must_be_chain->lightning_hrp))
b11->chain = must_be_chain;
else
return decode_fail(b11, fail, "Prefix %s is not for %s",
prefix + 2,
must_be_chain->network_name);
} else {
b11->chain = chainparams_by_lightning_hrp(prefix + 2);
if (!b11->chain)
return decode_fail(b11, fail, "Unknown chain %s",
prefix + 2);
}
/* BOLT #11:
*
* - if the `amount` is empty:
* */
amountstr = tal_strdup(tmpctx, hrp + strlen(prefix));
if (streq(amountstr, "")) {
/* BOLT #11:
*
* - SHOULD indicate to the payer that amount is unspecified.
*/
b11->msat = NULL;
} else {
u64 m10 = 10 * MSAT_PER_BTC; /* Pico satoshis in a Bitcoin */
u64 amount;
char *end;
/* Gather and trim multiplier */
end = amountstr + strlen(amountstr)-1;
for (size_t i = 0; i < ARRAY_SIZE(multipliers); i++) {
if (*end == multipliers[i].letter) {
m10 = multipliers[i].m10;
*end = '\0';
break;
}
}
/* BOLT #11:
*
* if `amount` contains a non-digit OR is followed by
* anything except a `multiplier` (see table above)... MUST fail the
* payment.
**/
amount = strtoull(amountstr, &end, 10);
if (amount == ULLONG_MAX && errno == ERANGE)
return decode_fail(b11, fail,
"Invalid amount '%s'", amountstr);
if (!*amountstr || *end)
return decode_fail(b11, fail,
"Invalid amount postfix '%s'", end);
/* BOLT #11:
*
* if the `multiplier` is present... MUST multiply
* `amount` by the `multiplier` value to derive the
* amount required for payment.
*/
b11->msat = tal(b11, struct amount_msat);
/* BOLT #11:
*
* - if multiplier is `p` and the last decimal of `amount` is
* not 0:
* - MUST fail the payment.
*/
if (amount * m10 % 10 != 0)
return decode_fail(b11, fail,
"Invalid sub-millisatoshi amount"
" '%sp'", amountstr);
*b11->msat = amount_msat(amount * m10 / 10);
}
/* BOLT #11:
*
* The data part of a Lightning invoice consists of multiple sections:
*
* 1. `timestamp`: seconds-since-1970 (35 bits, big-endian)
* 1. zero or more tagged parts
* 1. `signature`: Bitcoin-style signature of above (520 bits)
*/
err = pull_uint(&hu5, &data, &data_len, &b11->timestamp, 35);
if (err)
return decode_fail(b11, fail,
"Can't get 35-bit timestamp: %s", err);
while (data_len > 520 / 5) {
const char *problem = NULL;
u64 type, field_len64;
size_t field_len;
const struct decoder *decoder;
/* BOLT #11:
*
* Each Tagged Field is of the form:
*
* 1. `type` (5 bits)
* 1. `data_length` (10 bits, big-endian)
* 1. `data` (`data_length` x 5 bits)
*/
err = pull_uint(&hu5, &data, &data_len, &type, 5);
if (err)
return decode_fail(b11, fail,
"Can't get tag: %s", err);
err = pull_uint(&hu5, &data, &data_len, &field_len64, 10);
if (err)
return decode_fail(b11, fail,
"Can't get length: %s", err);
/* Can't exceed total data remaining. */
if (field_len64 > data_len)
return decode_fail(b11, fail, "%c: truncated",
bech32_charset[type]);
/* These are different types on 32 bit! But since data_len is
* also size_t, above check ensures this will fit. */
field_len = field_len64;
assert(field_len == field_len64);
/* Do this now: the decode function fixes up the data ptr */
data_len -= field_len;
decoder = find_decoder(bech32_charset[type]);
if (!decoder || (have_field[type] && !decoder->allow_duplicates)) {
problem = unknown_field(b11, &hu5, &data, &field_len,
bech32_charset[type]);
} else {
problem = decoder->decode(b11, our_features, &hu5,
&data, &field_len, &have_field[type]);
}
if (problem)
return decode_fail(b11, fail, "%s", problem);
if (field_len)
return decode_fail(b11, fail, "%c: extra %zu bytes",
bech32_charset[type], field_len);
}
if (!have_field[bech32_charset_rev['p']])
return decode_fail(b11, fail, "No valid 'p' field found");
if (have_field[bech32_charset_rev['h']] && description) {
struct sha256 sha;
/* BOLT #11:
*
* A reader... MUST check that the SHA2 256-bit hash
* in the `h` field exactly matches the hashed
* description.
*/
sha256(&sha, description, strlen(description));
if (!sha256_eq(b11->description_hash, &sha))
return decode_fail(b11, fail,
"h: does not match description");
}
/* BOLT #11:
* A writer:
*...
* - MUST include either exactly one `d` or exactly one `h` field.
*/
/* FIXME: It doesn't actually say the reader must check though! */
if (!have_field[bech32_charset_rev['d']]
&& !have_field[bech32_charset_rev['h']])
return decode_fail(b11, fail,
"must have either 'd' or 'h' field");
hash_u5_done(&hu5, hash);
*sig = tal_dup_arr(ctx, u5, data, data_len, 0);
*have_n = have_field[bech32_charset_rev['n']];
return b11;
}
static bool valid_recovery_id(u8 recid) { return recid <= 3; }
/* Decodes and checks signature; returns NULL on error. */
struct bolt11 *bolt11_decode(const tal_t *ctx, const char *str,
const struct feature_set *our_features,
const char *description,
const struct chainparams *must_be_chain,
char **fail)
{
const u5 *sigdata;
size_t data_len;
u8 sig_and_recid[65];
secp256k1_ecdsa_recoverable_signature sig;
struct bolt11 *b11;
struct sha256 hash;
bool have_n;
const char *err;
b11 = bolt11_decode_nosig(ctx, str, our_features, description,
must_be_chain, &hash, &sigdata, &have_n,
fail);
if (!b11)
return NULL;
/* BOLT #11:
*
* A writer...MUST set `signature` to a valid 512-bit
* secp256k1 signature of the SHA2 256-bit hash of the
* human-readable part, represented as UTF-8 bytes,
* concatenated with the data part (excluding the signature)
* with 0 bits appended to pad the data to the next byte
* boundary, with a trailing byte containing the recovery ID
* (0, 1, 2, or 3).
*/
data_len = tal_count(sigdata);
err = pull_bits(NULL, &sigdata, &data_len, sig_and_recid, 520, false);
if (err)
return decode_fail(b11, fail, "can't read signature: %s",
err);
assert(data_len == 0);
if (!valid_recovery_id(sig_and_recid[64]))
return decode_fail(b11, fail, "invalid recovery ID: %u",
sig_and_recid[64]);
if (!secp256k1_ecdsa_recoverable_signature_parse_compact
(secp256k1_ctx, &sig, sig_and_recid, sig_and_recid[64]))
return decode_fail(b11, fail, "signature invalid");
secp256k1_ecdsa_recoverable_signature_convert(secp256k1_ctx,
&b11->sig, &sig);
/* BOLT #11:
*
* A reader... MUST check that the `signature` is valid (see
* the `n` tagged field specified below). ... A reader...
* MUST use the `n` field to validate the signature instead of
* performing signature recovery.
*/
if (!have_n) {
struct pubkey k;
if (!secp256k1_ecdsa_recover(secp256k1_ctx,
&k.pubkey,
&sig,
(const u8 *)&hash))
return decode_fail(b11, fail,
"signature recovery failed");
node_id_from_pubkey(&b11->receiver_id, &k);
} else {
struct pubkey k;
/* n parsing checked this! */
if (!pubkey_from_node_id(&k, &b11->receiver_id))
abort();
if (!secp256k1_ecdsa_verify(secp256k1_ctx, &b11->sig,
(const u8 *)&hash,
&k.pubkey))
return decode_fail(b11, fail, "invalid signature");
}
return b11;
}
/* Helper for pushing a variable-length big-endian int. */
static void push_varlen_uint(u5 **data, u64 val, size_t nbits)
{
be64 be_val = cpu_to_be64(val << (64 - nbits));
bech32_push_bits(data, &be_val, nbits);
}
/* BOLT #11:
*
* Each Tagged Field is of the form:
*
* 1. `type` (5 bits)
* 1. `data_length` (10 bits, big-endian)
* 1. `data` (`data_length` x 5 bits)
*/
static void push_field_type_and_len(u5 **data, char type, size_t nbits)
{
assert(bech32_charset_rev[(unsigned char)type] >= 0);
push_varlen_uint(data, bech32_charset_rev[(unsigned char)type], 5);
push_varlen_uint(data, (nbits + 4) / 5, 10);
}
static void push_field(u5 **data, char type, const void *src, size_t nbits)
{
push_field_type_and_len(data, type, nbits);
bech32_push_bits(data, src, nbits);
}
/* BOLT #11:
*
* - if `x` is included:
* - SHOULD use the minimum `data_length` possible.
* - SHOULD include one `c` field (`min_final_cltv_expiry_delta`).
*...
* - SHOULD use the minimum `data_length` possible.
*/
static void push_varlen_field(u5 **data, char type, u64 val)
{
assert(bech32_charset_rev[(unsigned char)type] >= 0);
push_varlen_uint(data, bech32_charset_rev[(unsigned char)type], 5);
for (size_t nbits = 5; nbits < 65; nbits += 5) {
if ((val >> nbits) == 0) {
push_varlen_uint(data, nbits / 5, 10);
push_varlen_uint(data, val, nbits);
return;
}
}
/* Can't be encoded in <= 60 bits. */
abort();
}
/* BOLT #11:
*
* `f` (9): `data_length` variable, depending on version. Fallback
* on-chain address: for Bitcoin, this starts with a 5-bit `version`
* and contains a witness program or P2PKH or P2SH address.
*/
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);
bech32_push_bits(data, addr, addr_len * CHAR_BIT);
}
static void encode_p(u5 **data, const struct sha256 *hash)
{
push_field(data, 'p', hash, 256);
}
static void encode_m(u5 **data, const u8 *metadata)
{
push_field(data, 'm', metadata, tal_bytelen(metadata) * CHAR_BIT);
}
static void encode_d(u5 **data, const char *description)
{
push_field(data, 'd', description, strlen(description) * CHAR_BIT);
}
static void encode_h(u5 **data, const struct sha256 *hash)
{
push_field(data, 'h', hash, 256);
}
static void encode_n(u5 **data, const struct node_id *id)
{
assert(node_id_valid(id));
push_field(data, 'n', id->k, sizeof(id->k) * CHAR_BIT);
}
static void encode_x(u5 **data, u64 expiry)
{
push_varlen_field(data, 'x', expiry);
}
static void encode_c(u5 **data, u16 min_final_cltv_expiry)
{
if (dev_bolt11_omit_c_value)
return;
push_varlen_field(data, 'c', min_final_cltv_expiry);
}
static void encode_s(u5 **data, const struct secret *payment_secret)
{
push_field(data, 's', payment_secret, 256);
}
static void encode_f(u5 **data, const u8 *fallback)
{
struct bitcoin_address pkh;
struct ripemd160 sh;
struct sha256 wsh;
/* BOLT #11:
*
* for Bitcoin payments... MUST set an `f` field to a valid
* witness version and program, OR to `17` followed by a
* public key hash, OR to `18` followed by a script hash.
*/
if (is_p2pkh(fallback, &pkh)) {
push_fallback_addr(data, 17, &pkh, sizeof(pkh));
} else if (is_p2sh(fallback, &sh)) {
push_fallback_addr(data, 18, &sh, sizeof(sh));
} else if (is_p2wpkh(fallback, &pkh)) {
push_fallback_addr(data, 0, &pkh, sizeof(pkh));
} else if (is_p2wsh(fallback, &wsh)) {
push_fallback_addr(data, 0, &wsh, sizeof(wsh));
} else if (tal_count(fallback) > 1
&& fallback[0] >= 0x50
&& fallback[0] < (0x50+16)) {
/* Other (future) witness versions: turn OP_N into N */
push_fallback_addr(data, fallback[0] - 0x50, fallback + 2,
tal_count(fallback) - 2);
} else {
/* Copy raw. */
push_field(data, 'f',
fallback, tal_count(fallback) * CHAR_BIT);
}
}
static void encode_r(u5 **data, const struct route_info *r)
{
u8 *rinfo = tal_arr(NULL, u8, 0);
for (size_t i = 0; i < tal_count(r); i++)
towire_route_info(&rinfo, &r[i]);
push_field(data, 'r', rinfo, tal_count(rinfo) * CHAR_BIT);
tal_free(rinfo);
}
static void maybe_encode_9(u5 **data, const u8 *features,
bool have_payment_metadata)
{
u5 *f5 = tal_arr(NULL, u5, 0);
for (size_t i = 0; i < tal_count(features) * CHAR_BIT; i++) {
if (!feature_is_set(features, i))
continue;
/* Don't set option_payment_metadata unless we acually use it */
if (!have_payment_metadata
&& COMPULSORY_FEATURE(i) == OPT_PAYMENT_METADATA)
continue;
/* We expand it out so it makes a BE 5-bit/btye bitfield */
set_feature_bit(&f5, (i / 5) * 8 + (i % 5));
}
/* BOLT #11:
*
* - if `9` contains non-zero bits:
* - SHOULD use the minimum `data_length` possible.
* - otherwise:
* - MUST omit the `9` field altogether.
*/
if (tal_count(f5) != 0) {
push_field_type_and_len(data, '9', tal_count(f5) * 5);
tal_expand(data, f5, tal_count(f5));
}
tal_free(f5);
}
static bool encode_extra(u5 **data, const struct bolt11_field *extra)
{
size_t len;
/* Can't encode an invalid tag. */
if (bech32_charset_rev[(unsigned char)extra->tag] == -1)
return false;
push_varlen_uint(data, bech32_charset_rev[(unsigned char)extra->tag], 5);
push_varlen_uint(data, tal_count(extra->data), 10);
/* extra->data is already u5s, so do this raw. */
len = tal_count(*data);
tal_resize(data, len + tal_count(extra->data));
memcpy(*data + len, extra->data, tal_count(extra->data));
return true;
}
/* Encodes, even if it's nonsense. */
char *bolt11_encode_(const tal_t *ctx,
const struct bolt11 *b11, bool n_field,
bool (*sign)(const u5 *u5bytes,
const u8 *hrpu8,
secp256k1_ecdsa_recoverable_signature *rsig,
void *arg),
void *arg)
{
u5 *data = tal_arr(tmpctx, u5, 0);
char *hrp, *output;
u64 amount;
struct bolt11_field *extra;
secp256k1_ecdsa_recoverable_signature rsig;
u8 sig_and_recid[65];
u8 *hrpu8;
int recid;
/* BOLT #11:
*
* A writer:
* - MUST encode `prefix` using the currency required for successful payment.
* - if a specific minimum `amount` is required for successful payment:
* - MUST include that `amount`.
* - MUST encode `amount` as a positive decimal integer with no leading 0s.
* - If the `p` multiplier is used the last decimal of `amount` MUST be `0`.
* - SHOULD use the shortest representation possible, by using the largest multiplier or omitting the multiplier.
*/
if (b11->msat) {
char postfix;
u64 msat = b11->msat->millisatoshis; /* Raw: best-multiplier calc */
if (msat % MSAT_PER_BTC == 0) {
postfix = '\0';
amount = msat / MSAT_PER_BTC;
} else {
size_t i;
for (i = 0; i < ARRAY_SIZE(multipliers)-1; i++) {
if (!(msat * 10 % multipliers[i].m10))
break;
}
postfix = multipliers[i].letter;
amount = msat * 10 / multipliers[i].m10;
}
hrp = tal_fmt(tmpctx, "ln%s%"PRIu64"%c",
b11->chain->lightning_hrp, amount, postfix);
} else
hrp = tal_fmt(tmpctx, "ln%s", b11->chain->lightning_hrp);
/* BOLT #11:
*
* 1. `timestamp`: seconds-since-1970 (35 bits, big-endian)
* 1. zero or more tagged parts
* 1. `signature`: Bitcoin-style signature of above (520 bits)
*/
push_varlen_uint(&data, b11->timestamp, 35);
/* This is a hack to match the test vectors, *some* of which
* order differently! */
if (!dev_bolt11_old_order) {
if (b11->payment_secret)
encode_s(&data, b11->payment_secret);
}
/* BOLT #11:
*
* if a writer offers more than one of any field type,
* it... MUST specify the most-preferred field first, followed
* by less-preferred fields, in order.
*/
/* Thus we do built-in fields, then extras last. */
encode_p(&data, &b11->payment_hash);
/* BOLT #11:
* A writer:
*...
* - MUST include either exactly one `d` or exactly one `h` field.
*/
/* We sometimes keep description around (to put in db), so prefer hash */
if (b11->description_hash)
encode_h(&data, b11->description_hash);
else if (b11->description)
encode_d(&data, b11->description);
if (b11->metadata)
encode_m(&data, b11->metadata);
if (n_field)
encode_n(&data, &b11->receiver_id);
if (dev_bolt11_old_order) {
if (b11->payment_secret)
encode_s(&data, b11->payment_secret);
}
if (b11->expiry != DEFAULT_X)
encode_x(&data, b11->expiry);
/* BOLT #11:
* - SHOULD include one `c` field (`min_final_cltv_expiry_delta`).
*...
* A reader:
*...
* - if the `c` field (`min_final_cltv_expiry_delta`) is not provided:
* - MUST use an expiry delta of at least 18 when making the payment
*/
if (b11->min_final_cltv_expiry != 18)
encode_c(&data, b11->min_final_cltv_expiry);
for (size_t i = 0; i < tal_count(b11->fallbacks); i++)
encode_f(&data, b11->fallbacks[i]);
for (size_t i = 0; i < tal_count(b11->routes); i++)
encode_r(&data, b11->routes[i]);
maybe_encode_9(&data, b11->features, b11->metadata != NULL);
list_for_each(&b11->extra_fields, extra, list)
if (!encode_extra(&data, extra))
return NULL;
/* FIXME: towire_ should check this? */
if (tal_count(data) > 65535)
return NULL;
/* Need exact length here */
hrpu8 = tal_dup_arr(tmpctx, u8, (const u8 *)hrp, strlen(hrp), 0);
if (!sign(data, hrpu8, &rsig, arg))
return NULL;
secp256k1_ecdsa_recoverable_signature_serialize_compact(
secp256k1_ctx,
sig_and_recid,
&recid,
&rsig);
sig_and_recid[64] = recid;
bech32_push_bits(&data, sig_and_recid, sizeof(sig_and_recid) * CHAR_BIT);
output = tal_arr(ctx, char, strlen(hrp) + tal_count(data) + 8);
if (!bech32_encode(output, hrp, data, tal_count(data), (size_t)-1,
BECH32_ENCODING_BECH32))
output = tal_free(output);
return output;
}
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