dns: check dns seeds supporting service flags combinations

Author: naiyoma

check-dnsseeds.py

@@ -59,10 +59,26 @@ def check_seed(x):
     else:
         print(f"\x1b[91mFAIL\x1b[0m {x}")
 
-def has_answer_section(domain):
+def get_combinations(services):
+   
+    all_flags = services.values()
+    all_combinations = []
+
+    for i in range(1, len(all_flags) + 1):
+        for combo in combinations(all_flags, i):
+            combination_value = sum(combo)
+            combination_hex = hex(combination_value)[2:].upper()
+            combination_names = [service for service, flag in services.items() if flag in combo]
+            all_combinations.append((combination_hex, combination_names))
+  
+    return all_combinations
+
+def check_dns_support(combination_hex, provider):
     """
-    Executes a dig command for the given domain and checks for an answer section.
+    Checks if a DNS provider supports a given combination of flags.
     """
+    
+    domain = f"x{combination_hex}.{provider}"
     command = ["dig", domain]
     try:
         result = subprocess.run(command, capture_output=True, check=True)
@@ -71,14 +87,6 @@ def has_answer_section(domain):
     except subprocess.CalledProcessError:
         return False  
 
-def get_hex_from_combination(*flags):
-    """
-    Calculates the hexadecimal representation of the combination value.
-    """
-    combination_value = sum(flags)
-    hex_value = hex(combination_value)[2:].upper()
-    return f"x{hex_value}" 
-
 if __name__ == "__main__":
     print("\nBitcoin Core DNS Seed Status Check:\n")
 
@@ -91,23 +99,22 @@ def get_hex_from_combination(*flags):
         print()
 
     print("\n")
-
-    all_flags = [NODE_NONE, NODE_NETWORK, NODE_BLOOM, NODE_WITNESS, NODE_COMPACT_FILTERS, NODE_NETWORK_LIMITED, NODE_P2P_V2]
-    all_combinations = []
-
-    for i in range(1, len(all_flags) + 1):  
-        for combo in combinations(all_flags, i):
-            combination = sum(combo)  
-            hex_value = get_hex_from_combination(*combo)
-            all_combinations.append((combo, hex_value))  
-
-    print("All possible combinations and their hexadecimal values:")
-    for combination, hex_value in all_combinations:
-        combination_names = [flag_name for flag_name, flag_value in zip(["NODE_NONE", "NODE_NETWORK", "NODE_BLOOM", "NODE_WITNESS", "NODE_COMPACT_FILTERS", "NODE_NETWORK_LIMITED", "NODE_P2P_V2"], combination) if flag_value != 0]
-        combination_string = ", ".join(combination_names)
-        print(f"Combination: {combination_string} => Hexadecimal Value: {hex_value}")
+    combinations = get_combinations({
+        "NODE_NONE": NODE_NONE,
+        "NODE_NETWORK": NODE_NETWORK,
+        "NODE_BLOOM": NODE_BLOOM,
+        "NODE_WITNESS": NODE_WITNESS,
+        "NODE_COMPACT_FILTERS": NODE_COMPACT_FILTERS,
+        "NODE_NETWORK_LIMITED": NODE_NETWORK_LIMITED,
+        "NODE_P2P_V2": NODE_P2P_V2,
+    })
+
+    print("All possible combinations of node services and their bit flags in hexadecimal:")
+    for combination_hex, service_names in combinations:
+        print(f"  Bit flag (hex): {combination_hex} - Service: {', '.join(service_names)}")
 
         for provider in DNS_SEED_PROVIDERS:
-            domain = f"{hex_value}.{provider}"
-            has_answer = has_answer_section(domain)
-            print(f"  {domain}: {has_answer}")
+            supports_combination = check_dns_support(combination_hex, provider)
+            print(f"    Provider: {provider} - Supports Service: {supports_combination}")
+
+