blockchain: moved chainwork to blockindex

block: removed chainwork from block header
block: added chainwork parameter to deserialize functions
chainparams: added chainwork to genesis blocks and checkpoints
headersdb: added chainwork parameter to set_chainpoint_start
headersdb_file: added chainwork to genesis block and checkpoint
spv: added chainwork parameter to set checkpoint
validation: added chainwork parameter to check_auxpow
arith_uint256: updated add and sub_arith_uint256 to work from LSB
airht_uint256: updated set_compact to direct assignment
arith_uint256: updated sub_arith_uint256 to unsigned borrow
arith_uint256: updated sub_arith_uint256 to handle underflow
arith_uint256: added arith_shift functions to header
pow: updated target check with arith_uint256_is_zero
pow: updated uint256_cmp to work from MSB to LSB
pow: updated check_pow to swap_bytes in hash
tests: updated net and block tests
tests: added arith_uint256 tests
make: added arith_uint256 tests

CMakeLists.txt

@@ -303,6 +303,7 @@ IF(USE_TESTS)
     TARGET_SOURCES(tests ${visibility}
         test/address_tests.c
         test/aes_tests.c
+        test/arith_uint256_tests.c
         test/base58_tests.c
         test/bip32_tests.c
         test/bip39_tests.c

Makefile.am

@@ -180,6 +180,7 @@ if USE_TESTS
 noinst_PROGRAMS += tests
 tests_LDADD = libdogecoin.la $(ASM_LIB_FILES)
 tests_SOURCES = \
+    test/arith_uint256_tests.c \
     test/address_tests.c \
     test/aes_tests.c \
     test/base58_tests.c \

include/dogecoin/arith_uint256.h

@@ -53,6 +53,8 @@ typedef base_uint_ arith_uint256;
 
 void arith_negate(arith_uint256* input);
 arith_uint256* init_arith_uint256();
+void arith_shift_left(arith_uint256* input, unsigned int shift);
+void arith_shift_right(arith_uint256* input, unsigned int shift);
 arith_uint256* set_compact(arith_uint256* hash, uint32_t compact, dogecoin_bool *pf_negative, dogecoin_bool *pf_overflow);
 uint8_t* arith_to_uint256(const arith_uint256* a);
 arith_uint256* uint_to_arith(const uint256* a);

include/dogecoin/block.h

@@ -55,7 +55,6 @@ typedef struct dogecoin_block_header_ {
     uint32_t bits;
     uint32_t nonce;
     auxpow auxpow[1];
-    uint256 chainwork;
 } dogecoin_block_header;
 
 typedef struct dogecoin_auxpow_block_ {
@@ -75,8 +74,8 @@ LIBDOGECOIN_API dogecoin_block_header* dogecoin_block_header_new();
 LIBDOGECOIN_API void dogecoin_block_header_free(dogecoin_block_header* header);
 LIBDOGECOIN_API dogecoin_auxpow_block* dogecoin_auxpow_block_new();
 LIBDOGECOIN_API void dogecoin_auxpow_block_free(dogecoin_auxpow_block* block);
-LIBDOGECOIN_API int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct const_buffer* buf, const dogecoin_chainparams *params);
-LIBDOGECOIN_API int deserialize_dogecoin_auxpow_block(dogecoin_auxpow_block* block, struct const_buffer* buffer, const dogecoin_chainparams *params);
+LIBDOGECOIN_API int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct const_buffer* buf, const dogecoin_chainparams *params, uint256* chainwork);
+LIBDOGECOIN_API int deserialize_dogecoin_auxpow_block(dogecoin_auxpow_block* block, struct const_buffer* buffer, const dogecoin_chainparams *params, uint256* chainwork);
 LIBDOGECOIN_API void dogecoin_block_header_serialize(cstring* s, const dogecoin_block_header* header);
 LIBDOGECOIN_API void dogecoin_block_header_copy(dogecoin_block_header* dest, const dogecoin_block_header* src);
 LIBDOGECOIN_API dogecoin_bool dogecoin_block_header_hash(dogecoin_block_header* header, uint256 hash);

include/dogecoin/blockchain.h

@@ -40,6 +40,7 @@ LIBDOGECOIN_BEGIN_DECL
 typedef struct dogecoin_blockindex {
     uint32_t height;
     uint256 hash;
+    uint256 chainwork;
     dogecoin_block_header header;
     struct dogecoin_blockindex* prev;
 } dogecoin_blockindex;

include/dogecoin/chainparams.h

@@ -47,11 +47,13 @@ typedef struct dogecoin_chainparams_ {
     uint32_t b58prefix_bip32_pubkey;
     const unsigned char netmagic[4];
     uint256 genesisblockhash;
+    uint256 genesisblockchainwork;
     int default_port;
     dogecoin_dns_seed dnsseeds[8];
     dogecoin_bool strict_id;
     dogecoin_bool auxpow_id;
     uint256 pow_limit;
+    uint256 minimumchainwork;
 } dogecoin_chainparams;
 
 typedef struct dogecoin_checkpoint_ {
@@ -66,8 +68,8 @@ extern const dogecoin_chainparams dogecoin_chainparams_test;
 extern const dogecoin_chainparams dogecoin_chainparams_regtest;
 
 // the mainnet checkpoints, needs a fix size
-extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[22];
-extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[18];
+extern const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[23];
+extern const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[19];
 
 LIBDOGECOIN_API const dogecoin_chainparams* chain_from_b58_prefix(const char* address);
 LIBDOGECOIN_API int chain_from_b58_prefix_bool(char* address);

include/dogecoin/headersdb.h

@@ -52,7 +52,7 @@ typedef struct dogecoin_headers_db_interface_
     dogecoin_blockindex* (*getchaintip)(void *db);
     dogecoin_bool (*disconnect_tip)(void *db);
     dogecoin_bool (*has_checkpoint_start)(void *db);
-    void (*set_checkpoint_start)(void *db, uint256 hash, uint32_t height);
+    void (*set_checkpoint_start)(void *db, uint256 hash, uint32_t height, uint256 chainwork);
 } dogecoin_headers_db_interface;
 
 LIBDOGECOIN_END_DECL

include/dogecoin/headersdb_file.h

@@ -63,7 +63,7 @@ dogecoin_blockindex * dogecoin_headersdb_find(dogecoin_headers_db* db, uint256 h
 dogecoin_blockindex * dogecoin_headersdb_getchaintip(dogecoin_headers_db* db);
 dogecoin_bool dogecoin_headersdb_disconnect_tip(dogecoin_headers_db* db);
 dogecoin_bool dogecoin_headersdb_has_checkpoint_start(dogecoin_headers_db* db);
-void dogecoin_headersdb_set_checkpoint_start(dogecoin_headers_db* db, uint256 hash, uint32_t height);
+void dogecoin_headersdb_set_checkpoint_start(dogecoin_headers_db* db, uint256 hash, uint32_t height, uint256 chainwork);
 
 static const dogecoin_headers_db_interface dogecoin_headers_db_interface_file = {
     (void* (*)(const dogecoin_chainparams*, dogecoin_bool))dogecoin_headers_db_new,
@@ -74,7 +74,7 @@ static const dogecoin_headers_db_interface dogecoin_headers_db_interface_file =
     (dogecoin_blockindex* (*)(void *))dogecoin_headersdb_getchaintip,
     (dogecoin_bool (*)(void *))dogecoin_headersdb_disconnect_tip,
     (dogecoin_bool (*)(void *))dogecoin_headersdb_has_checkpoint_start,
-    (void (*)(void *, uint256, uint32_t))dogecoin_headersdb_set_checkpoint_start
+    (void (*)(void *, uint256, uint32_t, uint256))dogecoin_headersdb_set_checkpoint_start
 };
 
 LIBDOGECOIN_END_DECL

include/dogecoin/validation.h

@@ -45,7 +45,7 @@ LIBDOGECOIN_BEGIN_DECL
 LIBDOGECOIN_API uint32_t get_chainid(uint32_t version);
 LIBDOGECOIN_API dogecoin_bool is_auxpow(uint32_t version);
 LIBDOGECOIN_API dogecoin_bool is_legacy(uint32_t version);
-LIBDOGECOIN_API dogecoin_bool check_auxpow(dogecoin_auxpow_block* block, dogecoin_chainparams* params);
+LIBDOGECOIN_API dogecoin_bool check_auxpow(dogecoin_auxpow_block* block, dogecoin_chainparams* params, uint256* chainwork);
 LIBDOGECOIN_API dogecoin_bool dogecoin_block_header_scrypt_hash(cstring* s, uint256* hash);
 
 LIBDOGECOIN_END_DECL

src/arith_uint256.c

@@ -88,9 +88,9 @@ arith_uint256* set_compact(arith_uint256* hash, uint32_t compact, dogecoin_bool
     uint32_t word = compact & 0x007fffff;
     if (size <= 3) {
         word >>= 8 * (3 - size);
-        memcpy_safe(&hash->pn[0], &word, sizeof word);
+        hash->pn[0] = word;
     } else {
-        memcpy_safe(&hash->pn[0], &word, sizeof word);
+        hash->pn[0] = word;
         arith_shift_left(hash, 8 * (size - 3));
     }
     if (pf_negative) *pf_negative = word != 0 && (compact & 0x00800000) != 0;
@@ -152,21 +152,27 @@ arith_uint256* div_arith_uint256(arith_uint256* a, arith_uint256* b) {
 arith_uint256* add_arith_uint256(arith_uint256* a, arith_uint256* b) {
     arith_uint256* result = init_arith_uint256();
     uint64_t carry = 0;
-    for (int i = WIDTH - 1; i >= 0; i--) {
+    for (int i = 0; i < WIDTH; i++) {
         uint64_t sum = (uint64_t)a->pn[i] + b->pn[i] + carry;
-        result->pn[i] = sum; // This will only keep the lower 32 bits
-        carry = sum >> 32; // This will keep the upper 32 bits (carry)
+        result->pn[i] = (uint32_t)sum; // This will only keep the lower 32 bits
+        carry = sum >> 32; // Carry is the upper 32 bits
     }
     return result;
 }
 
 arith_uint256* sub_arith_uint256(arith_uint256* a, arith_uint256* b) {
+    if (arith_uint256_less_than(a, b)) {
+        // Handle underflow if necessary
+        return NULL;
+    }
     arith_uint256* result = init_arith_uint256();
-    int64_t carry = 0;
-    for (int i = WIDTH - 1; i >= 0; i--) {
-        int64_t diff = (uint64_t)a->pn[i] - b->pn[i] - carry;
-        result->pn[i] = diff; // This will only keep the lower 32 bits
-        carry = (diff < 0) ? 1 : 0; // If diff is negative, there's a borrow
+    uint64_t borrow = 0;
+    for (int i = 0; i < WIDTH; i++) {
+        uint64_t diff = (uint64_t)a->pn[i] - b->pn[i] - borrow;
+        result->pn[i] = (uint32_t)diff; // Keep only lower 32 bits
+        // If diff is less than zero when interpreted as signed, there's a borrow.
+        // Note: This checks the high bit of the 64-bit diff calculation for borrow.
+        borrow = (diff > (uint64_t)UINT32_MAX) ? 1 : 0;
     }
     return result;
 }

src/block.c

@@ -168,7 +168,6 @@ dogecoin_block_header* dogecoin_block_header_new() {
     header->auxpow->check = check;
     header->auxpow->ctx = header;
     header->auxpow->is = false;
-    dogecoin_mem_zero(&header->chainwork, DOGECOIN_HASH_LENGTH);
     return header;
     }
 
@@ -310,10 +309,11 @@ void print_block(dogecoin_auxpow_block* block) {
  * @param header The header object to be constructed.
  * @param buf The buffer to deserialize from.
  * @param params The chain parameters.
+ * @param chainwork The computed chainwork.
  *
  * @return 1 if deserialization was successful, 0 otherwise.
  */
-int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct const_buffer* buf, const dogecoin_chainparams *params) {
+int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct const_buffer* buf, const dogecoin_chainparams *params, uint256* chainwork) {
     dogecoin_auxpow_block* block = dogecoin_auxpow_block_new();
     if (!deser_s32(&block->header->version, buf))
         return false;
@@ -329,7 +329,7 @@ int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct cons
         return false;
     dogecoin_block_header_copy(header, block->header);
     if ((block->header->version & 0x100) != 0 && buf->len) {
-        if (!deserialize_dogecoin_auxpow_block(block, buf, params)) {
+        if (!deserialize_dogecoin_auxpow_block(block, buf, params, chainwork)) {
             printf("%s:%d:%s:%s\n", __FILE__, __LINE__, __func__, strerror(errno));
             return false;
         }
@@ -339,7 +339,7 @@ int dogecoin_block_header_deserialize(dogecoin_block_header* header, struct cons
     return true;
     }
 
-int deserialize_dogecoin_auxpow_block(dogecoin_auxpow_block* block, struct const_buffer* buffer, const dogecoin_chainparams *params) {
+int deserialize_dogecoin_auxpow_block(dogecoin_auxpow_block* block, struct const_buffer* buffer, const dogecoin_chainparams *params, uint256* chainwork) {
     if (buffer->len > DOGECOIN_MAX_P2P_MSG_SIZE) {
         return printf("\ntransaction is invalid or to large.\n\n");
         }
@@ -428,7 +428,7 @@ int deserialize_dogecoin_auxpow_block(dogecoin_auxpow_block* block, struct const
         return false;
     }
 
-    if (!check_auxpow(block, (dogecoin_chainparams*)params)) {
+    if (!check_auxpow(block, (dogecoin_chainparams*)params, chainwork)) {
         printf("check_auxpow failed!\n");
         return false;
     }
@@ -473,7 +473,6 @@ void dogecoin_block_header_copy(dogecoin_block_header* dest, const dogecoin_bloc
     dest->auxpow->check = src->auxpow->check;
     dest->auxpow->ctx = src->auxpow->ctx;
     dest->auxpow->is = src->auxpow->is;
-    memcpy_safe(&dest->chainwork, &src->chainwork, sizeof(src->chainwork));
     }
 
 /**

src/chainparams.c

@@ -39,11 +39,13 @@ const dogecoin_chainparams dogecoin_chainparams_main = {
     0x02facafd,               // starts with dgub
     {0xc0, 0xc0, 0xc0, 0xc0}, // pch msg prefixes (magic bytes)
     {0x91, 0x56, 0x35, 0x2c, 0x18, 0x18, 0xb3, 0x2e, 0x90, 0xc9, 0xe7, 0x92, 0xef, 0xd6, 0xa1, 0x1a, 0x82, 0xfe, 0x79, 0x56, 0xa6, 0x30, 0xf0, 0x3b, 0xbe, 0xe2, 0x36, 0xce, 0xda, 0xe3, 0x91, 0x1a},
+    {0x10, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
     22556,
     {{"seed.multidoge.org"}, {{1}}},
     true,
     0x0062,
-    {0x00, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff} // pow limit
+    {0x00, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, // pow limit
+    {0x9b, 0xa4, 0x46, 0xf2, 0x6c, 0xa8, 0x2a, 0x3d, 0x99, 0x0e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 };
 
 const dogecoin_chainparams dogecoin_chainparams_test = {
@@ -56,11 +58,13 @@ const dogecoin_chainparams dogecoin_chainparams_test = {
     0x043587cf,               // starts with tpub
     {0xfc, 0xc1, 0xb7, 0xdc}, // pch msg prefixes (magic bytes)
     {0x9e, 0x55, 0x50, 0x73, 0xd0, 0xc4, 0xf3, 0x64, 0x56, 0xdb, 0x89, 0x51, 0xf4, 0x49, 0x70, 0x4d, 0x54, 0x4d, 0x28, 0x26, 0xd9, 0xaa, 0x60, 0x63, 0x6b, 0x40, 0x37, 0x46, 0x26, 0x78, 0x0a, 0xbb},
+    {0x10, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
     44556,
     {{"testseed.jrn.me.uk"}, {{0}}},
     false,
     0x0062,
-    {0x00, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff} // pow limit
+    {0x00, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, // pow limit
+    {0x26, 0x9a, 0xff, 0x62, 0x2f, 0x0f, 0x54, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 };
 
 const dogecoin_chainparams dogecoin_chainparams_regtest = {
@@ -73,11 +77,13 @@ const dogecoin_chainparams dogecoin_chainparams_regtest = {
     0x043587cf,               // starts with tpub
     {0xfa, 0xbf, 0xb5, 0xda}, // pch msg prefixes (magic bytes)
     {0xa5, 0x73, 0xe9, 0x1c, 0x17, 0x72, 0x07, 0x6c, 0x0d, 0x40, 0xf7, 0x0e, 0x44, 0x08, 0xc8, 0x3a, 0x31, 0x70, 0x5f, 0x29, 0x6a, 0xe6, 0xe7, 0x62, 0x9d, 0x4a, 0xdc, 0xb5, 0xa3, 0x60, 0x21, 0x3d},
+    {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
     18332,
     {{"testseed.jrn.me.uk"}, {{0}}},
     true,
     0x0062,
-    {0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff} // pow limit
+    {0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, // pow limit
+    {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 };
 
 const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[] = {
@@ -102,7 +108,8 @@ const dogecoin_checkpoint dogecoin_mainnet_checkpoint_array[] = {
     {3606083, "954c7c66dee51f0a3fb1edb26200b735f5275fe54d9505c76ebd2bcabac36f1e", 1613218169, 0x1a03d764},
     {3854173, "e4b4ecda4c022406c502a247c0525480268ce7abbbef632796e8ca1646425e75", 1628934997, 0x1a03ca36},
     {3963597, "2b6927cfaa5e82353d45f02be8aadd3bfd165ece5ce24b9bfa4db20432befb5d", 1635884460, 0x1a037bc9},
-    {4303965, "ed7d266dcbd8bb8af80f9ccb8deb3e18f9cc3f6972912680feeb37b090f8cee0", 1657646310, 0x1a0344f5}};
+    {4303965, "ed7d266dcbd8bb8af80f9ccb8deb3e18f9cc3f6972912680feeb37b090f8cee0", 1657646310, 0x1a0344f5},
+    {5050000, "e7d4577405223918491477db725a393bcfc349d8ee63b0a4fde23cbfbfd81dea", 1705383360, 0x1a019541}};
 
 const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[] = {
     {0, "bb0a78264637406b6360aad926284d544d7049f45189db5664f3c4d07350559e", 1391503289, 0x1e0ffff0},
@@ -122,7 +129,8 @@ const dogecoin_checkpoint dogecoin_testnet_checkpoint_array[] = {
     {3062910, "113c41c00934f940a41f99d18b2ad9aefd183a4b7fe80527e1e6c12779bd0246", 1613218844, 0x1e0e2221},
     {3286675, "07fef07a255d510297c9189dc96da5f4e41a8184bc979df8294487f07fee1cf3", 1628932841, 0x1e0fffff},
     {3445426, "70574db7856bd685abe7b0a8a3e79b29882620645bd763b01459176bceb58cd1", 1635884611, 0x1e0fffff},
-    {3976284, "af23c3e750bb4f2ce091235f006e7e4e2af453d4c866282e7870471dcfeb4382", 1657646588, 0x1e0fffff}};
+    {3976284, "af23c3e750bb4f2ce091235f006e7e4e2af453d4c866282e7870471dcfeb4382", 1657646588, 0x1e0fffff},
+    {5900000, "199bea6a442310589cbb50a193a30b097c228bd5a0f21af21e4e53dd57c382d3", 1703511130, 0x1e0fffff}};
 
 const dogecoin_chainparams* chain_from_b58_prefix(const char* address) {
     /* determine address prefix for network chainparams */