diff --git a/Makefile b/Makefile index 729015ca2..8cc2a238b 100644 --- a/Makefile +++ b/Makefile @@ -3,7 +3,7 @@ # Needs to have oneof support: Ubuntu vivid's is too old :( PROTOCC:=protoc-c -PROGRAMS := open-channel open-anchor-scriptsigs leak-anchor-sigs open-commit-sig check-commit-sig check-anchor-scriptsigs get-anchor-depth create-steal-tx create-commit-spend-tx close-channel create-close-tx +PROGRAMS := open-channel open-anchor-scriptsigs leak-anchor-sigs open-commit-sig check-commit-sig check-anchor-scriptsigs get-anchor-depth create-steal-tx create-commit-spend-tx close-channel create-close-tx update-channel HELPER_OBJS := base58.o lightning.pb-c.o shadouble.o pkt.o bitcoin_script.o permute_tx.o signature.o bitcoin_tx.o bitcoin_address.o anchor.o commit_tx.o pubkey.o opt_bits.o close_tx.o find_p2sh_out.o diff --git a/check-commit-sig.c b/check-commit-sig.c index 25df03075..7f14f2af8 100644 --- a/check-commit-sig.c +++ b/check-commit-sig.c @@ -69,7 +69,7 @@ int main(int argc, char *argv[]) anchor_txid(anchor, argv[5], argv[6], inmap, &txid); /* Now create our commitment tx. */ - commit = create_commit_tx(ctx, o1, o2, &txid, outmap[0]); + commit = create_commit_tx(ctx, o1, o2, 0, &txid, outmap[0]); /* If contributions don't exceed fees, this fails. */ if (!commit) diff --git a/commit_tx.c b/commit_tx.c index 3d7eafcfa..f5ba280c6 100644 --- a/commit_tx.c +++ b/commit_tx.c @@ -9,6 +9,7 @@ struct bitcoin_tx *create_commit_tx(const tal_t *ctx, OpenChannel *ours, OpenChannel *theirs, + int64_t delta, const struct sha256_double *anchor_txid, unsigned int anchor_output) { @@ -42,7 +43,11 @@ struct bitcoin_tx *create_commit_tx(const tal_t *ctx, if (ours->anchor->total < ours->commitment_fee) return tal_free(tx); tx->output[0].amount = ours->anchor->total - ours->commitment_fee; - + /* Asking for more than we have? */ + if (delta < 0 && -delta > tx->output[0].amount) + return tal_free(tx); + tx->output[0].amount += delta; + /* Second output is a P2SH payment to them. */ if (!proto_to_pubkey(theirs->final, &to_me)) return tal_free(tx); @@ -54,6 +59,10 @@ struct bitcoin_tx *create_commit_tx(const tal_t *ctx, if (theirs->anchor->total < theirs->commitment_fee) return tal_free(tx); tx->output[1].amount = theirs->anchor->total - theirs->commitment_fee; + /* Asking for more than they have? */ + if (delta > 0 && delta > tx->output[1].amount) + return tal_free(tx); + tx->output[0].amount -= delta; permute_outputs(ours->seed, theirs->seed, 1, tx->output, 2, NULL); return tx; diff --git a/commit_tx.h b/commit_tx.h index c5afe6a12..bdba13f33 100644 --- a/commit_tx.h +++ b/commit_tx.h @@ -10,6 +10,7 @@ struct sha256_double; struct bitcoin_tx *create_commit_tx(const tal_t *ctx, OpenChannel *ours, OpenChannel *theirs, + int64_t delta, const struct sha256_double *anchor_txid, unsigned int anchor_output); #endif diff --git a/open-commit-sig.c b/open-commit-sig.c index 3b85d1b30..45a91eda7 100644 --- a/open-commit-sig.c +++ b/open-commit-sig.c @@ -65,7 +65,7 @@ int main(int argc, char *argv[]) anchor_txid(anchor, argv[4], argv[5], inmap, &txid); /* Now create THEIR commitment tx to spend 2/2 output of anchor. */ - commit = create_commit_tx(ctx, o2, o1, &txid, outmap[0]); + commit = create_commit_tx(ctx, o2, o1, 0, &txid, outmap[0]); /* If contributions don't exceed fees, this fails. */ if (!commit) diff --git a/pkt.c b/pkt.c index 023917d10..63c7b2bb2 100644 --- a/pkt.c +++ b/pkt.c @@ -152,3 +152,15 @@ struct pkt *close_channel_complete_pkt(const tal_t *ctx, c.sig = signature_to_proto(ctx, sig); return to_pkt(ctx, PKT__PKT_CLOSE_COMPLETE, &c); } + +struct pkt *update_pkt(const tal_t *ctx, + const struct sha256 *revocation_hash, + s64 delta, struct signature *sig) +{ + Update u = UPDATE__INIT; + u.revocation_hash = sha256_to_proto(ctx, revocation_hash); + u.delta = delta; + u.sig = signature_to_proto(ctx, sig); + return to_pkt(ctx, PKT__PKT_UPDATE, &u); +} + diff --git a/pkt.h b/pkt.h index 433f93949..7e4be5792 100644 --- a/pkt.h +++ b/pkt.h @@ -81,6 +81,17 @@ struct pkt *close_channel_pkt(const tal_t *ctx, const struct signature *sig); struct pkt *close_channel_complete_pkt(const tal_t *ctx, const struct signature *sig); +/** + * update_pkt - create an update message + * @ctx: tal context to allocate off. + * @revocation_hash: the revocation hash for the next tx. + * @delta: the change in satoshis (to me). + * @sig: the signature for the close transaction input. + */ +struct pkt *update_pkt(const tal_t *ctx, + const struct sha256 *revocation_hash, + s64 delta, struct signature *sig); + /* Useful helper for allocating & populating a protobuf Sha256Hash */ Sha256Hash *sha256_to_proto(const tal_t *ctx, const struct sha256 *hash); void proto_to_sha256(const Sha256Hash *pb, struct sha256 *hash); diff --git a/update-channel.c b/update-channel.c new file mode 100644 index 000000000..96a24fe07 --- /dev/null +++ b/update-channel.c @@ -0,0 +1,128 @@ +/* My example: + * ./update-channel A-open.pb B-open.pb anchor.tx > A-update-1.pb + */ +#include +#include +#include +#include +#include +#include +#include +#include "lightning.pb-c.h" +#include "anchor.h" +#include "base58.h" +#include "pkt.h" +#include "bitcoin_script.h" +#include "permute_tx.h" +#include "signature.h" +#include "commit_tx.h" +#include "pubkey.h" +#include "find_p2sh_out.h" +#include +#include + +int main(int argc, char *argv[]) +{ + const tal_t *ctx = tal_arr(NULL, char, 0); + struct sha256 seed, revocation_hash; + OpenChannel *o1, *o2; + struct bitcoin_tx *anchor, *commit; + struct sha256_double anchor_txid; + struct pkt *pkt; + struct signature sig; + EC_KEY *privkey; + bool testnet; + struct pubkey pubkey1, pubkey2; + u8 *redeemscript; + unsigned long long to_them = 0, from_them = 0; + int64_t delta, this_delta; + size_t i; + + err_set_progname(argv[0]); + + opt_register_noarg("--help|-h", opt_usage_and_exit, + " [previous-updates]\n" + "Create a new update message", + "Print this message."); + opt_register_arg("--to-them=", + opt_set_ulonglongval_si, NULL, &to_them, + "Amount to pay them (must use this or --from-them)"); + opt_register_arg("--from-them=", + opt_set_ulonglongval_si, NULL, &from_them, + "Amount to pay us (must use this or --to-them)"); + + opt_parse(&argc, argv, opt_log_stderr_exit); + + if (!from_them && !to_them) + opt_usage_exit_fail("Must use --to-them or --from-them"); + + if (argc < 5) + opt_usage_exit_fail("Expected 4+ arguments"); + + if (!hex_decode(argv[1], strlen(argv[1]), &seed, sizeof(seed))) + errx(1, "Invalid seed '%s' - need 256 hex bits", argv[1]); + + this_delta = from_them - to_them; + if (!this_delta) + errx(1, "Delta must not be zero"); + + 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]); + + /* Figure out cumulative delta since anchor. */ + delta = this_delta; + for (i = 6; 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 - 5, &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); + + /* Now create THEIR new commitment tx to spend 2/2 output of anchor. */ + commit = create_commit_tx(ctx, o2, o1, delta, &anchor_txid, + find_p2sh_out(anchor, redeemscript)); + + /* If contributions don't exceed fees, this fails. */ + if (!commit) + errx(1, "Delta too large"); + + /* Their pubkey must be valid */ + if (!proto_to_pubkey(o2->anchor->pubkey, &pubkey2)) + errx(1, "Invalid public open-channel-file2"); + + /* Sign it for them. */ + sign_tx_input(ctx, commit, 0, redeemscript, tal_count(redeemscript), + privkey, &sig); + + pkt = update_pkt(ctx, &revocation_hash, delta, &sig); + if (!write_all(STDOUT_FILENO, pkt, + sizeof(pkt->len) + le32_to_cpu(pkt->len))) + err(1, "Writing out packet"); + + tal_free(ctx); + return 0; +} +