chainparams: Add liquid_fee_asset to determine which asset pays fees

This is required since liquid-regtest and liquidv1 have different asset tags
for L-BTC which is the fee-paying asset.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

bitcoin/chainparams.c

@@ -12,6 +12,18 @@
 #define BIP32_VER_SIGT_PUBLIC  0x043587CF
 #define BIP32_VER_SIGT_PRIVATE 0x04358394
 
+static u8 liquid_fee_asset[] = {
+    0x01, 0x6d, 0x52, 0x1c, 0x38, 0xec, 0x1e, 0xa1, 0x57, 0x34, 0xae,
+    0x22, 0xb7, 0xc4, 0x60, 0x64, 0x41, 0x28, 0x29, 0xc0, 0xd0, 0x57,
+    0x9f, 0x0a, 0x71, 0x3d, 0x1c, 0x04, 0xed, 0xe9, 0x79, 0x02, 0x6f,
+};
+
+static u8 liquid_regtest_fee_asset[] = {
+    0x01, 0x5c, 0xe7, 0xb9, 0x63, 0xd3, 0x7f, 0x8f, 0x2d, 0x51, 0xca,
+    0xfb, 0xba, 0x92, 0x8a, 0xaa, 0x9e, 0x22, 0x0b, 0x8b, 0xbc, 0x66,
+    0x05, 0x71, 0x49, 0x9c, 0x03, 0x62, 0x8a, 0x38, 0x51, 0xb8, 0xce,
+};
+
 const struct chainparams networks[] = {
     {.network_name = "bitcoin",
      .bip173_name = "bc",
@@ -39,6 +51,7 @@ const struct chainparams networks[] = {
      .p2pkh_version = 0,
      .p2sh_version = 5,
      .testnet = false,
+     .fee_asset_tag = NULL,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_MAIN_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_MAIN_PRIVATE},
      .is_elements = false},
@@ -61,6 +74,7 @@ const struct chainparams networks[] = {
      .p2pkh_version = 111,
      .p2sh_version = 196,
      .testnet = true,
+     .fee_asset_tag = NULL,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_TEST_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_TEST_PRIVATE},
      .is_elements = false},
@@ -100,6 +114,7 @@ const struct chainparams networks[] = {
      .p2pkh_version = 111,
      .p2sh_version = 196,
      .testnet = true,
+     .fee_asset_tag = NULL,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_TEST_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_TEST_PRIVATE},
      .is_elements = false},
@@ -122,6 +137,7 @@ const struct chainparams networks[] = {
      .p2pkh_version = 48,
      .p2sh_version = 50,
      .testnet = false,
+     .fee_asset_tag = NULL,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_MAIN_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_MAIN_PRIVATE},
      .is_elements = false},
@@ -144,11 +160,13 @@ const struct chainparams networks[] = {
      .p2pkh_version = 111,
      .p2sh_version = 58,
      .testnet = true,
+     .fee_asset_tag = NULL,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_TEST_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_TEST_PRIVATE},
      .is_elements = false},
     {.network_name = "liquid-regtest",
      .bip173_name = "ert",
+     .bip70_name = "liquid-regtest",
      .genesis_blockhash = {{{.u.u8 = {0x9f, 0x87, 0xeb, 0x58, 0x0b, 0x9e, 0x5f,
 				      0x11, 0xdc, 0x21, 0x1e, 0x9f, 0xb6, 0x6a,
 				      0xbb, 0x36, 0x99, 0x99, 0x90, 0x44, 0xf8,
@@ -164,11 +182,13 @@ const struct chainparams networks[] = {
      .p2pkh_version = 91,
      .p2sh_version = 75,
      .testnet = true,
+     .fee_asset_tag = liquid_regtest_fee_asset,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_TEST_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_TEST_PRIVATE},
      .is_elements = true},
     {.network_name = "liquid",
      .bip173_name = "ex",
+     .bip70_name = "liquidv1",
      .genesis_blockhash = {{{.u.u8 = {0x14, 0x66, 0x27, 0x58, 0x36, 0x22, 0x0d,
 				      0xb2, 0x94, 0x4c, 0xa0, 0x59, 0xa3, 0xa1,
 				      0x0e, 0xf6, 0xfd, 0x2e, 0xa6, 0x84, 0xb0,
@@ -184,6 +204,7 @@ const struct chainparams networks[] = {
      .p2pkh_version = 57,
      .p2sh_version = 39,
      .testnet = false,
+     .fee_asset_tag = liquid_fee_asset,
      .bip32_key_version = {.bip32_pubkey_version = BIP32_VER_MAIN_PUBLIC,
 			   .bip32_privkey_version = BIP32_VER_MAIN_PRIVATE},
      .is_elements = true},

bitcoin/chainparams.h

@@ -38,6 +38,7 @@ struct chainparams {
 	/* Version codes for BIP32 extended keys in libwally-core*/
 	const struct bip32_key_version bip32_key_version;
 	const bool is_elements;
+	const u8 *fee_asset_tag;
 };
 
 /**