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#include "address.h"
#include "locktime.h"
#include "preimage.h"
#include "pubkey.h"
#include "script.h"
#include <assert.h>
#include <ccan/crypto/ripemd160/ripemd160.h>
#include <ccan/crypto/sha256/sha256.h>
#include <ccan/endian/endian.h>
#include <ccan/mem/mem.h>
/* Some standard ops */
#define OP_0 0x00
#define OP_PUSHBYTES(val) (val)
#define OP_PUSHDATA1 0x4C
#define OP_PUSHDATA2 0x4D
#define OP_PUSHDATA4 0x4E
#define OP_NOP 0x61
#define OP_IF 0x63
#define OP_NOTIF 0x64
#define OP_ELSE 0x67
#define OP_ENDIF 0x68
#define OP_RETURN 0x6a
#define OP_2DROP 0x6d
#define OP_DEPTH 0x74
#define OP_DROP 0x75
#define OP_DUP 0x76
#define OP_SWAP 0x7c
#define OP_EQUAL 0x87
#define OP_EQUALVERIFY 0x88
#define OP_SIZE 0x82
#define OP_1SUB 0x8C
#define OP_ADD 0x93
#define OP_CHECKSIG 0xAC
#define OP_CHECKMULTISIG 0xAE
#define OP_HASH160 0xA9
#define OP_CHECKSEQUENCEVERIFY 0xB2
#define OP_CHECKLOCKTIMEVERIFY 0xB1
/* Bitcoin's OP_HASH160 is RIPEMD(SHA256()) */
static void hash160(struct ripemd160 *redeemhash, const void *mem, size_t len)
{
struct sha256 h;
sha256(&h, mem, len);
ripemd160(redeemhash, h.u.u8, sizeof(h));
}
static void add(u8 **scriptp, const void *mem, size_t len)
{
size_t oldlen = tal_count(*scriptp);
tal_resize(scriptp, oldlen + len);
memcpy(*scriptp + oldlen, mem, len);
}
static void add_op(u8 **scriptp, u8 op)
{
add(scriptp, &op, 1);
}
static void add_push_bytes(u8 **scriptp, const void *mem, size_t len)
{
if (len < 76)
add_op(scriptp, OP_PUSHBYTES(len));
else if (len < 256) {
char c = len;
add_op(scriptp, OP_PUSHDATA1);
add(scriptp, &c, 1);
} else if (len < 65536) {
le16 v = cpu_to_le16(len);
add_op(scriptp, OP_PUSHDATA2);
add(scriptp, &v, 2);
} else {
le32 v = cpu_to_le32(len);
add_op(scriptp, OP_PUSHDATA4);
add(scriptp, &v, 4);
}
add(scriptp, memcheck(mem, len), len);
}
static void add_number(u8 **script, u32 num)
{
if (num == 0)
add_op(script, 0);
else if (num <= 16)
add_op(script, 0x50 + num);
else {
le64 n = cpu_to_le64(num);
/* Beware: encoding is signed! */
if (num <= 0x0000007F)
add_push_bytes(script, &n, 1);
else if (num <= 0x00007FFF)
add_push_bytes(script, &n, 2);
else if (num <= 0x007FFFFF)
add_push_bytes(script, &n, 3);
else if (num <= 0x7FFFFFFF)
add_push_bytes(script, &n, 4);
else
add_push_bytes(script, &n, 5);
}
}
static void add_push_key(u8 **scriptp, const struct pubkey *key)
{
u8 der[PUBKEY_CMPR_LEN];
pubkey_to_der(der, key);
add_push_bytes(scriptp, der, sizeof(der));
}
static void add_push_sig(u8 **scriptp, const struct bitcoin_signature *sig)
{
u8 der[73];
size_t len = signature_to_der(der, sig);
add_push_bytes(scriptp, der, len);
}
static u8 *stack_key(const tal_t *ctx, const struct pubkey *key)
{
u8 der[PUBKEY_CMPR_LEN];
pubkey_to_der(der, key);
return tal_dup_arr(ctx, u8, der, sizeof(der), 0);
}
/* Bitcoin wants DER encoding. */
static u8 *stack_sig(const tal_t *ctx, const struct bitcoin_signature *sig)
{
u8 der[73];
size_t len = signature_to_der(der, sig);
return tal_dup_arr(ctx, u8, der, len, 0);
}
static u8 *stack_preimage(const tal_t *ctx, const struct preimage *preimage)
{
return tal_dup_arr(ctx, u8, preimage->r, sizeof(preimage->r), 0);
}
/* Bitcoin script stack values are a special, special snowflake.
*
* They're little endian values, but 0 is an empty value. We only
* handle single byte values here. */
static u8 *stack_number(const tal_t *ctx, unsigned int num)
{
u8 val;
if (num == 0)
return tal_arr(ctx, u8, 0);
val = num;
assert(val == num);
/* We use tal_dup_arr since we want tal_count() to work */
return tal_dup_arr(ctx, u8, &val, 1, 0);
}
/* tal_count() gives the length of the script. */
u8 *bitcoin_redeem_2of2(const tal_t *ctx,
const struct pubkey *key1,
const struct pubkey *key2)
{
u8 *script = tal_arr(ctx, u8, 0);
add_number(&script, 2);
if (pubkey_cmp(key1, key2) < 0) {
add_push_key(&script, key1);
add_push_key(&script, key2);
} else {
add_push_key(&script, key2);
add_push_key(&script, key1);
}
add_number(&script, 2);
add_op(&script, OP_CHECKMULTISIG);
return script;
}
u8 *scriptpubkey_p2sh_hash(const tal_t *ctx, const struct ripemd160 *redeemhash)
{
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_HASH160);
add_push_bytes(&script, redeemhash->u.u8, sizeof(redeemhash->u.u8));
add_op(&script, OP_EQUAL);
assert(tal_count(script) == BITCOIN_SCRIPTPUBKEY_P2SH_LEN);
return script;
}
/* Create p2sh for this redeem script. */
u8 *scriptpubkey_p2sh(const tal_t *ctx, const u8 *redeemscript)
{
struct ripemd160 redeemhash;
hash160(&redeemhash, redeemscript, tal_count(redeemscript));
return scriptpubkey_p2sh_hash(ctx, &redeemhash);
}
/* Create an output script using p2pkh */
u8 *scriptpubkey_p2pkh(const tal_t *ctx, const struct bitcoin_address *addr)
{
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_DUP);
add_op(&script, OP_HASH160);
add_push_bytes(&script, &addr->addr, sizeof(addr->addr));
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_CHECKSIG);
assert(tal_count(script) == BITCOIN_SCRIPTPUBKEY_P2PKH_LEN);
return script;
}
u8 *scriptpubkey_opreturn(const tal_t *ctx)
{
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_RETURN);
return script;
}
/* Create an input script which spends p2pkh */
u8 *bitcoin_redeem_p2pkh(const tal_t *ctx, const struct pubkey *pubkey,
const struct bitcoin_signature *sig)
{
u8 *script = tal_arr(ctx, u8, 0);
add_push_sig(&script, sig);
add_push_key(&script, pubkey);
return script;
}
/* Create the redeemscript for a P2SH + P2WPKH (for signing tx) */
u8 *bitcoin_redeem_p2sh_p2wpkh(const tal_t *ctx, const struct pubkey *key)
{
struct ripemd160 keyhash;
u8 *script = tal_arr(ctx, u8, 0);
/* BIP141: BIP16 redeemScript pushed in the scriptSig is exactly a
* push of a version byte plus a push of a witness program. */
add_number(&script, 0);
pubkey_to_hash160(key, &keyhash);
add_push_bytes(&script, &keyhash, sizeof(keyhash));
assert(tal_count(script) == BITCOIN_SCRIPTPUBKEY_P2WPKH_LEN);
return script;
}
u8 *bitcoin_scriptsig_p2sh_p2wpkh(const tal_t *ctx, const struct pubkey *key)
{
u8 *redeemscript = bitcoin_redeem_p2sh_p2wpkh(ctx, key), *script;
/* BIP141: The scriptSig must be exactly a push of the BIP16
* redeemScript or validation fails. */
script = tal_arr(ctx, u8, 0);
add_push_bytes(&script, redeemscript, tal_count(redeemscript));
tal_free(redeemscript);
return script;
}
u8 **bitcoin_witness_p2wpkh(const tal_t *ctx,
const struct bitcoin_signature *sig,
const struct pubkey *key)
{
u8 **witness;
/* BIP141: The witness must consist of exactly 2 items (≤ 520
* bytes each). The first one a signature, and the second one
* a public key. */
witness = tal_arr(ctx, u8 *, 2);
witness[0] = stack_sig(witness, sig);
witness[1] = stack_key(witness, key);
return witness;
}
/* Create an output script for a 32-byte witness. */
u8 *scriptpubkey_p2wsh(const tal_t *ctx, const u8 *witnessscript)
{
struct sha256 h;
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_0);
sha256(&h, witnessscript, tal_count(witnessscript));
add_push_bytes(&script, h.u.u8, sizeof(h.u.u8));
assert(tal_count(script) == BITCOIN_SCRIPTPUBKEY_P2WSH_LEN);
return script;
}
/* Create an output script for a 20-byte witness. */
u8 *scriptpubkey_p2wpkh(const tal_t *ctx, const struct pubkey *key)
{
struct ripemd160 h;
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_0);
pubkey_to_hash160(key, &h);
add_push_bytes(&script, &h, sizeof(h));
return script;
}
u8 *scriptpubkey_p2wpkh_derkey(const tal_t *ctx, const u8 der[33])
{
u8 *script = tal_arr(ctx, u8, 0);
struct ripemd160 h;
add_op(&script, OP_0);
hash160(&h, der, PUBKEY_CMPR_LEN);
add_push_bytes(&script, &h, sizeof(h));
return script;
}
u8 *scriptpubkey_witness_raw(const tal_t *ctx, u8 version,
const u8 *wprog, size_t wprog_size)
{
u8 *script = tal_arr(ctx, u8, 0);
add_number(&script, version);
add_push_bytes(&script, wprog, wprog_size);
return script;
}
/* Create a witness which spends the 2of2. */
u8 **bitcoin_witness_2of2(const tal_t *ctx,
const struct bitcoin_signature *sig1,
const struct bitcoin_signature *sig2,
const struct pubkey *key1,
const struct pubkey *key2)
{
u8 **witness = tal_arr(ctx, u8 *, 4);
/* OP_CHECKMULTISIG has an out-by-one bug, which MBZ */
witness[0] = stack_number(witness, 0);
/* sig order should match key order. */
if (pubkey_cmp(key1, key2) < 0) {
witness[1] = stack_sig(witness, sig1);
witness[2] = stack_sig(witness, sig2);
} else {
witness[1] = stack_sig(witness, sig2);
witness[2] = stack_sig(witness, sig1);
}
witness[3] = bitcoin_redeem_2of2(witness, key1, key2);
return witness;
}
/* Create scriptcode (fake witness, basically) for P2WPKH */
u8 *p2wpkh_scriptcode(const tal_t *ctx, const struct pubkey *key)
{
struct ripemd160 pkhash;
u8 *script = tal_arr(ctx, u8, 0);
pubkey_to_hash160(key, &pkhash);
/* BIP143:
*
* For P2WPKH witness program, the scriptCode is
* 0x1976a914{20-byte-pubkey-hash}88ac.
*/
/* PUSH(25): OP_DUP OP_HASH160 PUSH(20) 20-byte-pubkey-hash
* OP_EQUALVERIFY OP_CHECKSIG */
add_op(&script, OP_DUP);
add_op(&script, OP_HASH160);
add_push_bytes(&script, &pkhash, sizeof(pkhash));
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_CHECKSIG);
return script;
}
bool is_p2pkh(const u8 *script, struct bitcoin_address *addr)
{
size_t script_len = tal_count(script);
if (script_len != BITCOIN_SCRIPTPUBKEY_P2PKH_LEN)
return false;
if (script[0] != OP_DUP)
return false;
if (script[1] != OP_HASH160)
return false;
if (script[2] != OP_PUSHBYTES(20))
return false;
if (script[23] != OP_EQUALVERIFY)
return false;
if (script[24] != OP_CHECKSIG)
return false;
if (addr)
memcpy(addr, script+3, 20);
return true;
}
bool is_p2sh(const u8 *script, struct ripemd160 *addr)
{
size_t script_len = tal_count(script);
if (script_len != BITCOIN_SCRIPTPUBKEY_P2SH_LEN)
return false;
if (script[0] != OP_HASH160)
return false;
if (script[1] != OP_PUSHBYTES(20))
return false;
if (script[22] != OP_EQUAL)
return false;
if (addr)
memcpy(addr, script+2, 20);
return true;
}
bool is_p2wsh(const u8 *script, struct sha256 *addr)
{
size_t script_len = tal_count(script);
if (script_len != BITCOIN_SCRIPTPUBKEY_P2WSH_LEN)
return false;
if (script[0] != OP_0)
return false;
if (script[1] != OP_PUSHBYTES(sizeof(struct sha256)))
return false;
if (addr)
memcpy(addr, script+2, sizeof(struct sha256));
return true;
}
bool is_p2wpkh(const u8 *script, struct bitcoin_address *addr)
{
size_t script_len = tal_count(script);
if (script_len != BITCOIN_SCRIPTPUBKEY_P2WPKH_LEN)
return false;
if (script[0] != OP_0)
return false;
if (script[1] != OP_PUSHBYTES(sizeof(struct ripemd160)))
return false;
if (addr)
memcpy(addr, script+2, sizeof(*addr));
return true;
}
u8 **bitcoin_witness_sig_and_element(const tal_t *ctx,
const struct bitcoin_signature *sig,
const void *elem, size_t elemsize,
const u8 *witnessscript)
{
u8 **witness = tal_arr(ctx, u8 *, 3);
witness[0] = stack_sig(witness, sig);
witness[1] = tal_dup_arr(witness, u8, elem, elemsize, 0);
witness[2] = tal_dup_arr(witness, u8,
witnessscript, tal_count(witnessscript), 0);
return witness;
}
/* BOLT #3:
*
* This output sends funds back to the owner of this commitment transaction and
* thus must be timelocked using `OP_CHECKSEQUENCEVERIFY`. It can be claimed, without delay,
* by the other party if they know the revocation private key. The output is a
* version-0 P2WSH, with a witness script:
*
* OP_IF
* # Penalty transaction
* <revocationpubkey>
* OP_ELSE
* `to_self_delay`
* OP_CHECKSEQUENCEVERIFY
* OP_DROP
* <local_delayedpubkey>
* OP_ENDIF
* OP_CHECKSIG
*/
u8 *bitcoin_wscript_to_local(const tal_t *ctx, u16 to_self_delay,
const struct pubkey *revocation_pubkey,
const struct pubkey *local_delayedkey)
{
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_IF);
add_push_key(&script, revocation_pubkey);
add_op(&script, OP_ELSE);
add_number(&script, to_self_delay);
add_op(&script, OP_CHECKSEQUENCEVERIFY);
add_op(&script, OP_DROP);
add_push_key(&script, local_delayedkey);
add_op(&script, OP_ENDIF);
add_op(&script, OP_CHECKSIG);
return script;
}
/* BOLT #3:
*
* #### Offered HTLC Outputs
*
* This output sends funds to either an HTLC-timeout transaction after the
* HTLC-timeout or to the remote node using the payment preimage or the
* revocation key. The output is a P2WSH, with a witness script:
*
* # To remote node with revocation key
* OP_DUP OP_HASH160 <RIPEMD160(SHA256(revocationpubkey))> OP_EQUAL
* OP_IF
* OP_CHECKSIG
* OP_ELSE
* <remote_htlcpubkey> OP_SWAP OP_SIZE 32 OP_EQUAL
* OP_NOTIF
* # To local node via HTLC-timeout transaction (timelocked).
* OP_DROP 2 OP_SWAP <local_htlcpubkey> 2 OP_CHECKMULTISIG
* OP_ELSE
* # To remote node with preimage.
* OP_HASH160 <RIPEMD160(payment_hash)> OP_EQUALVERIFY
* OP_CHECKSIG
* OP_ENDIF
* OP_ENDIF
*/
u8 *bitcoin_wscript_htlc_offer_ripemd160(const tal_t *ctx,
const struct pubkey *localhtlckey,
const struct pubkey *remotehtlckey,
const struct ripemd160 *payment_ripemd,
const struct pubkey *revocationkey)
{
u8 *script = tal_arr(ctx, u8, 0);
struct ripemd160 ripemd;
add_op(&script, OP_DUP);
add_op(&script, OP_HASH160);
pubkey_to_hash160(revocationkey, &ripemd);
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_IF);
add_op(&script, OP_CHECKSIG);
add_op(&script, OP_ELSE);
add_push_key(&script, remotehtlckey);
add_op(&script, OP_SWAP);
add_op(&script, OP_SIZE);
add_number(&script, 32);
add_op(&script, OP_EQUAL);
add_op(&script, OP_NOTIF);
add_op(&script, OP_DROP);
add_number(&script, 2);
add_op(&script, OP_SWAP);
add_push_key(&script, localhtlckey);
add_number(&script, 2);
add_op(&script, OP_CHECKMULTISIG);
add_op(&script, OP_ELSE);
add_op(&script, OP_HASH160);
add_push_bytes(&script,
payment_ripemd->u.u8, sizeof(payment_ripemd->u.u8));
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_CHECKSIG);
add_op(&script, OP_ENDIF);
add_op(&script, OP_ENDIF);
return script;
}
u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
const struct pubkey *localhtlckey,
const struct pubkey *remotehtlckey,
const struct sha256 *payment_hash,
const struct pubkey *revocationkey)
{
struct ripemd160 ripemd;
ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
return bitcoin_wscript_htlc_offer_ripemd160(ctx, localhtlckey,
remotehtlckey,
&ripemd, revocationkey);
}
/* BOLT #3:
*
* #### Received HTLC Outputs
*
* This output sends funds to either the remote node after the HTLC-timeout or
* using the revocation key, or to an HTLC-success transaction with a
* successful payment preimage. The output is a P2WSH, with a witness script:
*
* # To remote node with revocation key
* OP_DUP OP_HASH160 <RIPEMD160(SHA256(revocationpubkey))> OP_EQUAL
* OP_IF
* OP_CHECKSIG
* OP_ELSE
* <remote_htlcpubkey> OP_SWAP
* OP_SIZE 32 OP_EQUAL
* OP_IF
* # To local node via HTLC-success transaction.
* OP_HASH160 <RIPEMD160(payment_hash)> OP_EQUALVERIFY
* 2 OP_SWAP <local_htlcpubkey> 2 OP_CHECKMULTISIG
* OP_ELSE
* # To remote node after timeout.
* OP_DROP <cltv_expiry> OP_CHECKLOCKTIMEVERIFY OP_DROP
* OP_CHECKSIG
* OP_ENDIF
* OP_ENDIF
*/
u8 *bitcoin_wscript_htlc_receive_ripemd(const tal_t *ctx,
const struct abs_locktime *htlc_abstimeout,
const struct pubkey *localhtlckey,
const struct pubkey *remotehtlckey,
const struct ripemd160 *payment_ripemd,
const struct pubkey *revocationkey)
{
u8 *script = tal_arr(ctx, u8, 0);
struct ripemd160 ripemd;
add_op(&script, OP_DUP);
add_op(&script, OP_HASH160);
pubkey_to_hash160(revocationkey, &ripemd);
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_IF);
add_op(&script, OP_CHECKSIG);
add_op(&script, OP_ELSE);
add_push_key(&script, remotehtlckey);
add_op(&script, OP_SWAP);
add_op(&script, OP_SIZE);
add_number(&script, 32);
add_op(&script, OP_EQUAL);
add_op(&script, OP_IF);
add_op(&script, OP_HASH160);
add_push_bytes(&script,
payment_ripemd->u.u8, sizeof(payment_ripemd->u.u8));
add_op(&script, OP_EQUALVERIFY);
add_number(&script, 2);
add_op(&script, OP_SWAP);
add_push_key(&script, localhtlckey);
add_number(&script, 2);
add_op(&script, OP_CHECKMULTISIG);
add_op(&script, OP_ELSE);
add_op(&script, OP_DROP);
add_number(&script, htlc_abstimeout->locktime);
add_op(&script, OP_CHECKLOCKTIMEVERIFY);
add_op(&script, OP_DROP);
add_op(&script, OP_CHECKSIG);
add_op(&script, OP_ENDIF);
add_op(&script, OP_ENDIF);
return script;
}
u8 *bitcoin_wscript_htlc_receive(const tal_t *ctx,
const struct abs_locktime *htlc_abstimeout,
const struct pubkey *localhtlckey,
const struct pubkey *remotehtlckey,
const struct sha256 *payment_hash,
const struct pubkey *revocationkey)
{
struct ripemd160 ripemd;
ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
return bitcoin_wscript_htlc_receive_ripemd(ctx, htlc_abstimeout,
localhtlckey, remotehtlckey,
&ripemd, revocationkey);
}
/* BOLT #3:
*
* ## HTLC-Timeout and HTLC-Success Transactions
*
*...
* * `txin[0]` witness stack: `0 <remotehtlcsig> <localhtlcsig> <payment_preimage>` for HTLC-success, `0 <remotehtlcsig> <localhtlcsig> 0` for HTLC-timeout
*/
u8 **bitcoin_witness_htlc_timeout_tx(const tal_t *ctx,
const struct bitcoin_signature *localhtlcsig,
const struct bitcoin_signature *remotehtlcsig,
const u8 *wscript)
{
u8 **witness = tal_arr(ctx, u8 *, 5);
witness[0] = stack_number(witness, 0);
witness[1] = stack_sig(witness, remotehtlcsig);
witness[2] = stack_sig(witness, localhtlcsig);
witness[3] = stack_number(witness, 0);
witness[4] = tal_dup_arr(witness, u8, wscript, tal_count(wscript), 0);
return witness;
}
u8 **bitcoin_witness_htlc_success_tx(const tal_t *ctx,
const struct bitcoin_signature *localhtlcsig,
const struct bitcoin_signature *remotesig,
const struct preimage *preimage,
const u8 *wscript)
{
u8 **witness = tal_arr(ctx, u8 *, 5);
witness[0] = stack_number(witness, 0);
witness[1] = stack_sig(witness, remotesig);
witness[2] = stack_sig(witness, localhtlcsig);
witness[3] = stack_preimage(witness, preimage);
witness[4] = tal_dup_arr(witness, u8, wscript, tal_count(wscript), 0);
return witness;
}
u8 *bitcoin_wscript_htlc_tx(const tal_t *ctx,
u16 to_self_delay,
const struct pubkey *revocation_pubkey,
const struct pubkey *local_delayedkey)
{
u8 *script = tal_arr(ctx, u8, 0);
/* BOLT #3:
*
* The witness script for the output is:
*
* OP_IF
* # Penalty transaction
* <revocationpubkey>
* OP_ELSE
* `to_self_delay`
* OP_CHECKSEQUENCEVERIFY
* OP_DROP
* <local_delayedpubkey>
* OP_ENDIF
* OP_CHECKSIG
*/
add_op(&script, OP_IF);
add_push_key(&script, revocation_pubkey);
add_op(&script, OP_ELSE);
add_number(&script, to_self_delay);
add_op(&script, OP_CHECKSEQUENCEVERIFY);
add_op(&script, OP_DROP);
add_push_key(&script, local_delayedkey);
add_op(&script, OP_ENDIF);
add_op(&script, OP_CHECKSIG);
return script;
}
bool scripteq(const u8 *s1, const u8 *s2)
{
memcheck(s1, tal_count(s1));
memcheck(s2, tal_count(s2));
if (tal_count(s1) != tal_count(s2))
return false;
return memcmp(s1, s2, tal_count(s1)) == 0;
}