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/* My example:
* ./update-channel-accept <B-SEED> B-open.pb A-open.pb anchor.tx <B-TMPKEY> A-update-1.pb > B-update-accept-1.pb
*/
#include <ccan/crypto/shachain/shachain.h>
#include <ccan/short_types/short_types.h>
#include <ccan/tal/tal.h>
#include <ccan/opt/opt.h>
#include <ccan/str/hex/hex.h>
#include <ccan/err/err.h>
#include <ccan/read_write_all/read_write_all.h>
#include "lightning.pb-c.h"
#include "anchor.h"
#include "bitcoin/base58.h"
#include "pkt.h"
#include "bitcoin/script.h"
#include "permute_tx.h"
#include "bitcoin/signature.h"
#include "commit_tx.h"
#include "bitcoin/pubkey.h"
#include "find_p2sh_out.h"
#include "protobuf_convert.h"
#include <openssl/ec.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
const tal_t *ctx = tal_arr(NULL, char, 0);
struct sha256 seed, revocation_hash, their_rhash;
OpenChannel *o1, *o2;
Update *update;
struct bitcoin_tx *anchor, *commit;
struct sha256_double anchor_txid;
struct pkt *pkt;
struct bitcoin_signature sig;
EC_KEY *privkey;
bool testnet;
struct pubkey pubkey1, pubkey2;
u8 *redeemscript;
int64_t delta;
size_t i, p2sh_out;
err_set_progname(argv[0]);
opt_register_noarg("--help|-h", opt_usage_and_exit,
"<seed> <anchor-tx> <open-channel-file1> <open-channel-file2> <commit-privkey> <update-protobuf> [previous-updates]\n"
"Accept a new update message",
"Print this message.");
opt_parse(&argc, argv, opt_log_stderr_exit);
if (argc < 6)
opt_usage_exit_fail("Expected 5+ arguments");
if (!hex_decode(argv[1], strlen(argv[1]), &seed, sizeof(seed)))
errx(1, "Invalid seed '%s' - need 256 hex bits", argv[1]);
anchor = bitcoin_tx_from_file(ctx, argv[2]);
bitcoin_txid(anchor, &anchor_txid);
o1 = pkt_from_file(argv[3], PKT__PKT_OPEN)->open;
o2 = pkt_from_file(argv[4], PKT__PKT_OPEN)->open;
privkey = key_from_base58(argv[5], strlen(argv[5]), &testnet, &pubkey1);
if (!privkey)
errx(1, "Invalid private key '%s'", argv[5]);
if (!testnet)
errx(1, "Private key '%s' not on testnet!", argv[5]);
update = pkt_from_file(argv[6], PKT__PKT_UPDATE)->update;
/* Figure out cumulative delta since anchor. */
delta = update->delta;
for (i = 7; i < argc; i++) {
Update *u = pkt_from_file(argv[i], PKT__PKT_UPDATE)->update;
delta += u->delta;
}
/* Get next revocation hash. */
shachain_from_seed(&seed, argc - 6, &revocation_hash);
sha256(&revocation_hash,
revocation_hash.u.u8, sizeof(revocation_hash.u.u8));
/* Get pubkeys */
if (!proto_to_pubkey(o1->anchor->pubkey, &pubkey2))
errx(1, "Invalid o1 commit pubkey");
if (pubkey_len(&pubkey1) != pubkey_len(&pubkey2)
|| memcmp(pubkey1.key, pubkey2.key, pubkey_len(&pubkey2)) != 0)
errx(1, "o1 pubkey != this privkey");
if (!proto_to_pubkey(o2->anchor->pubkey, &pubkey2))
errx(1, "Invalid o2 final pubkey");
/* This is what the anchor pays to; figure out whick output. */
redeemscript = bitcoin_redeem_2of2(ctx, &pubkey1, &pubkey2);
p2sh_out = find_p2sh_out(anchor, redeemscript);
/* Now create THEIR new commitment tx to spend 2/2 output of anchor. */
proto_to_sha256(update->revocation_hash, &their_rhash);
commit = create_commit_tx(ctx, o2, o1, &their_rhash, delta,
&anchor_txid, p2sh_out);
/* If contributions don't exceed fees, this fails. */
if (!commit)
errx(1, "Delta too large");
/* Sign it for them. */
sign_tx_input(ctx, commit, 0, redeemscript, tal_count(redeemscript),
privkey, &pubkey1, &sig.sig);
pkt = update_accept_pkt(ctx, &sig.sig, &revocation_hash);
if (!write_all(STDOUT_FILENO, pkt,
sizeof(pkt->len) + le32_to_cpu(pkt->len)))
err(1, "Writing out packet");
tal_free(ctx);
return 0;
}