init: Require explicit -asmap filename

ryanofsky · ryanofsky · commit 44717da29b62 · 2025-11-05T08:43:58.000-05:00
Currently, if `-asmap` is specified without a filename bitcoind tries to load `ip_asn.map` data file. This change now requires `-asmap=ip_asn.map` or another filename to be specified explicitly. The change is intended to make behavior of the option explicit avoid confusion reported #33386 where documentation specifies a default file which is not actually loaded by default. It was originally implemented in #33631 (comment) and various alternatives are discussed there.
diff --git a/doc/release-notes-33770.md b/doc/release-notes-33770.md
@@ -0,0 +1,4 @@
+`-asmap` requires explicit filename
+-----------------------------------
+
+In previous releases, if `-asmap` was specified without a filename, this would try to load an `ip_asn.map` data file. Now loading an asmap file requires an explicit filename like `-asmap=ip_asn.map`. This change was made to make the option easier to understand, because it was confusing for there to be a default filename not actually loaded by default (https://github.com/bitcoin/bitcoin/issues/33386). Also this change makes the option more future-proof, because in upcoming releases, specifying `-asmap` will load embedded asmap data instead of an external file (https://github.com/bitcoin/bitcoin/pull/28792).
diff --git a/src/init.cpp b/src/init.cpp
@@ -158,7 +158,6 @@ static constexpr bool DEFAULT_STOPAFTERBLOCKIMPORT{false};
 #endif
 
 static constexpr int MIN_CORE_FDS = MIN_LEVELDB_FDS + NUM_FDS_MESSAGE_CAPTURE;
-static const char* DEFAULT_ASMAP_FILENAME="ip_asn.map";
 
 /**
  * The PID file facilities.
@@ -532,7 +531,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
                  ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 
     argsman.AddArg("-addnode=<ip>", strprintf("Add a node to connect to and attempt to keep the connection open (see the addnode RPC help for more info). This option can be specified multiple times to add multiple nodes; connections are limited to %u at a time and are counted separately from the -maxconnections limit.", MAX_ADDNODE_CONNECTIONS), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
-    argsman.AddArg("-asmap=<file>", strprintf("Specify asn mapping used for bucketing of the peers (default: %s). Relative paths will be prefixed by the net-specific datadir location.", DEFAULT_ASMAP_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-asmap=<file>", strprintf("Specify asn mapping used for bucketing of the peers (default: none). Relative paths will be prefixed by the net-specific datadir location."), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-bantime=<n>", strprintf("Default duration (in seconds) of manually configured bans (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-bind=<addr>[:<port>][=onion]", strprintf("Bind to given address and always listen on it (default: 0.0.0.0). Use [host]:port notation for IPv6. Append =onion to tag any incoming connections to that address and port as incoming Tor connections (default: 127.0.0.1:%u=onion, testnet3: 127.0.0.1:%u=onion, testnet4: 127.0.0.1:%u=onion, signet: 127.0.0.1:%u=onion, regtest: 127.0.0.1:%u=onion)", defaultChainParams->GetDefaultPort() + 1, testnetChainParams->GetDefaultPort() + 1, testnet4ChainParams->GetDefaultPort() + 1, signetChainParams->GetDefaultPort() + 1, regtestChainParams->GetDefaultPort() + 1), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-cjdnsreachable", "If set, then this host is configured for CJDNS (connecting to fc00::/8 addresses would lead us to the CJDNS network, see doc/cjdns.md) (default: 0)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
@@ -1548,11 +1547,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         // Read asmap file if configured
         std::vector<bool> asmap;
         if (args.IsArgSet("-asmap") && !args.IsArgNegated("-asmap")) {
-            fs::path asmap_path = args.GetPathArg("-asmap", DEFAULT_ASMAP_FILENAME);
+            fs::path asmap_path = args.GetPathArg("-asmap");
             if (!asmap_path.is_absolute()) {
                 asmap_path = args.GetDataDirNet() / asmap_path;
             }
-            if (!fs::exists(asmap_path)) {
+            if (!fs::is_regular_file(asmap_path)) {
                 InitError(strprintf(_("Could not find asmap file %s"), fs::quoted(fs::PathToString(asmap_path))));
                 return false;
             }
diff --git a/test/functional/feature_asmap.py b/test/functional/feature_asmap.py
@@ -4,21 +4,9 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test asmap config argument for ASN-based IP bucketing.
 
-Verify node behaviour and debug log when launching bitcoind in these cases:
-
-1. `bitcoind` with no -asmap arg, using /16 prefix for IP bucketing
-
-2. `bitcoind -asmap=<absolute path>`, using the unit test skeleton asmap
-
-3. `bitcoind -asmap=<relative path>`, using the unit test skeleton asmap
-
-4. `bitcoind -asmap/-asmap=` with no file specified, using the default asmap
-
-5. `bitcoind -asmap` restart with an addrman containing new and tried entries
-
-6. `bitcoind -asmap` with no file specified and a missing default asmap file
-
-7. `bitcoind -asmap` with an empty (unparsable) default asmap file
+Verify node behaviour and debug log when launching bitcoind with different
+`-asmap` and `-noasmap` arg values, including absolute and relative paths, and
+with missing and unparseable files.
 
 The tests are order-independent.
 
@@ -29,7 +17,6 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
-DEFAULT_ASMAP_FILENAME = 'ip_asn.map' # defined in src/init.cpp
 ASMAP = 'src/test/data/asmap.raw' # path to unit test skeleton asmap
 VERSION = 'fec61fa21a9f46f3b17bdcd660d7f4cd90b966aad3aec593c99b35f0aca15853'
 
@@ -79,52 +66,49 @@ def test_asmap_with_relative_path(self):
             self.start_node(0, [f'-asmap={name}'])
         os.remove(filename)
 
-    def test_default_asmap(self):
-        shutil.copyfile(self.asmap_raw, self.default_asmap)
+    def test_unspecified_asmap(self):
+        msg = f"Error: Could not find asmap file \"{self.datadir}{os.sep}\""
         for arg in ['-asmap', '-asmap=']:
-            self.log.info(f'Test bitcoind {arg} (using default map file)')
+            self.log.info(f'Test bitcoind {arg} (and no filename specified)')
             self.stop_node(0)
-            with self.node.assert_debug_log(expected_messages(self.default_asmap)):
-                self.start_node(0, [arg])
-        os.remove(self.default_asmap)
+            self.node.assert_start_raises_init_error(extra_args=[arg], expected_msg=msg)
 
     def test_asmap_interaction_with_addrman_containing_entries(self):
         self.log.info("Test bitcoind -asmap restart with addrman containing new and tried entries")
         self.stop_node(0)
-        shutil.copyfile(self.asmap_raw, self.default_asmap)
-        self.start_node(0, ["-asmap", "-checkaddrman=1", "-test=addrman"])
+        self.start_node(0, [f"-asmap={self.asmap_raw}", "-checkaddrman=1", "-test=addrman"])
         self.fill_addrman(node_id=0)
-        self.restart_node(0, ["-asmap", "-checkaddrman=1", "-test=addrman"])
+        self.restart_node(0, [f"-asmap={self.asmap_raw}", "-checkaddrman=1", "-test=addrman"])
         with self.node.assert_debug_log(
             expected_msgs=[
                 "CheckAddrman: new 2, tried 2, total 4 started",
                 "CheckAddrman: completed",
             ]
         ):
             self.node.getnodeaddresses()  # getnodeaddresses re-runs the addrman checks
-        os.remove(self.default_asmap)
 
-    def test_default_asmap_with_missing_file(self):
-        self.log.info('Test bitcoind -asmap with missing default map file')
+    def test_asmap_with_missing_file(self):
+        self.log.info('Test bitcoind -asmap with missing map file')
         self.stop_node(0)
-        msg = f"Error: Could not find asmap file \"{self.default_asmap}\""
-        self.node.assert_start_raises_init_error(extra_args=['-asmap'], expected_msg=msg)
+        msg = f"Error: Could not find asmap file \"{self.datadir}{os.sep}missing\""
+        self.node.assert_start_raises_init_error(extra_args=['-asmap=missing'], expected_msg=msg)
 
     def test_empty_asmap(self):
         self.log.info('Test bitcoind -asmap with empty map file')
         self.stop_node(0)
-        with open(self.default_asmap, "w", encoding="utf-8") as f:
+
+        empty_asmap = os.path.join(self.datadir, "ip_asn.map")
+        with open(empty_asmap, "w", encoding="utf-8") as f:
             f.write("")
-        msg = f"Error: Could not parse asmap file \"{self.default_asmap}\""
-        self.node.assert_start_raises_init_error(extra_args=['-asmap'], expected_msg=msg)
-        os.remove(self.default_asmap)
+        msg = f"Error: Could not parse asmap file \"{empty_asmap}\""
+        self.node.assert_start_raises_init_error(extra_args=[f'-asmap={empty_asmap}'], expected_msg=msg)
+        os.remove(empty_asmap)
 
     def test_asmap_health_check(self):
         self.log.info('Test bitcoind -asmap logs ASMap Health Check with basic stats')
-        shutil.copyfile(self.asmap_raw, self.default_asmap)
         msg = "ASMap Health Check: 4 clearnet peers are mapped to 3 ASNs with 0 peers being unmapped"
         with self.node.assert_debug_log(expected_msgs=[msg]):
-            self.start_node(0, extra_args=['-asmap'])
+            self.start_node(0, extra_args=[f'-asmap={self.asmap_raw}'])
         raw_addrman = self.node.getrawaddrman()
         asns = []
         for _, entries in raw_addrman.items():
@@ -133,22 +117,20 @@ def test_asmap_health_check(self):
                 if asn not in asns:
                     asns.append(asn)
         assert_equal(len(asns), 3)
-        os.remove(self.default_asmap)
 
     def run_test(self):
         self.node = self.nodes[0]
         self.datadir = self.node.chain_path
-        self.default_asmap = os.path.join(self.datadir, DEFAULT_ASMAP_FILENAME)
         base_dir = self.config["environment"]["SRCDIR"]
         self.asmap_raw = os.path.join(base_dir, ASMAP)
 
         self.test_without_asmap_arg()
         self.test_noasmap_arg()
         self.test_asmap_with_absolute_path()
         self.test_asmap_with_relative_path()
-        self.test_default_asmap()
+        self.test_unspecified_asmap()
         self.test_asmap_interaction_with_addrman_containing_entries()
-        self.test_default_asmap_with_missing_file()
+        self.test_asmap_with_missing_file()
         self.test_empty_asmap()
         self.test_asmap_health_check()
 

-Original file line number
+Diff line change
@@ @@ -0,0 +1,4 @@ @@
 +`-asmap` requires explicit filename
 +-----------------------------------
++
 +In previous releases, if `-asmap` was specified without a filename, this would try to load an `ip_asn.map` data file. Now loading an asmap file requires an explicit filename like `-asmap=ip_asn.map`. This change was made to make the option easier to understand, because it was confusing for there to be a default filename not actually loaded by default (https://github.com/bitcoin/bitcoin/issues/33386). Also this change makes the option more future-proof, because in upcoming releases, specifying `-asmap` will load embedded asmap data instead of an external file (https://github.com/bitcoin/bitcoin/pull/28792).