fix: reject empty hostname in peer address in FFI (#318)

* fix: reject empty hostname in peer address in FFI

Fix a bug in Windows discovered in CI overhaul PR #253 where `:9999` was being accepted as a valid peer address on Windows due to DNS resolution differences.

* Drop step 1

Author: xdustinface

dash-spv-ffi/FFI_API.md

@@ -39,7 +39,7 @@ Functions: 27
 | Function | Description | Module |
 |----------|-------------|--------|
 | `dash_spv_ffi_client_update_config` | Update the running client's configuration | client |
-| `dash_spv_ffi_config_add_peer` | Adds a peer address to the configuration  Accepts either a full socket... | config |
+| `dash_spv_ffi_config_add_peer` | Adds a peer address to the configuration  Accepts socket addresses with or... | config |
 | `dash_spv_ffi_config_destroy` | Destroys an FFIClientConfig and frees its memory  # Safety - `config` must... | config |
 | `dash_spv_ffi_config_get_data_dir` | Gets the data directory path from the configuration  # Safety - `config`... | config |
 | `dash_spv_ffi_config_get_mempool_strategy` | Gets the mempool synchronization strategy  # Safety - `config` must be a... | config |
@@ -254,7 +254,7 @@ dash_spv_ffi_config_add_peer(config: *mut FFIClientConfig, addr: *const c_char,)
 ```
 
 **Description:**
-Adds a peer address to the configuration  Accepts either a full socket address (e.g., `192.168.1.1:9999` or `[::1]:19999`) or an IP-only string (e.g., "127.0.0.1" or "2001:db8::1"). When an IP-only string is given, the default P2P port for the configured network is used.  # Safety - `config` must be a valid pointer to an FFIClientConfig created by dash_spv_ffi_config_new/mainnet/testnet - `addr` must be a valid null-terminated C string containing a socket address or IP-only string - The caller must ensure both pointers remain valid for the duration of this call
+Adds a peer address to the configuration  Accepts socket addresses with or without port. When no port is specified, the default P2P port for the configured network is used.  Supported formats: - IP with port: `192.168.1.1:9999`, `[::1]:19999` - IP without port: `127.0.0.1`, `2001:db8::1` - Hostname with port: `node.example.com:9999` - Hostname without port: `node.example.com`  # Safety - `config` must be a valid pointer to an FFIClientConfig created by dash_spv_ffi_config_new/mainnet/testnet - `addr` must be a valid null-terminated C string containing a socket address or IP-only string - The caller must ensure both pointers remain valid for the duration of this call
 
 **Safety:**
 - `config` must be a valid pointer to an FFIClientConfig created by dash_spv_ffi_config_new/mainnet/testnet - `addr` must be a valid null-terminated C string containing a socket address or IP-only string - The caller must ensure both pointers remain valid for the duration of this call

dash-spv-ffi/include/dash_spv_ffi.h

@@ -609,9 +609,14 @@ int32_t dash_spv_ffi_config_set_max_peers(struct FFIClientConfig *config,
 /**
  * Adds a peer address to the configuration
  *
- * Accepts either a full socket address (e.g., `192.168.1.1:9999` or `[::1]:19999`)
- * or an IP-only string (e.g., "127.0.0.1" or "2001:db8::1"). When an IP-only
- * string is given, the default P2P port for the configured network is used.
+ * Accepts socket addresses with or without port. When no port is specified,
+ * the default P2P port for the configured network is used.
+ *
+ * Supported formats:
+ * - IP with port: `192.168.1.1:9999`, `[::1]:19999`
+ * - IP without port: `127.0.0.1`, `2001:db8::1`
+ * - Hostname with port: `node.example.com:9999`
+ * - Hostname without port: `node.example.com`
  *
  * # Safety
  * - `config` must be a valid pointer to an FFIClientConfig created by dash_spv_ffi_config_new/mainnet/testnet

dash-spv-ffi/src/config.rs

@@ -125,9 +125,14 @@ pub unsafe extern "C" fn dash_spv_ffi_config_set_max_peers(
 
 /// Adds a peer address to the configuration
 ///
-/// Accepts either a full socket address (e.g., `192.168.1.1:9999` or `[::1]:19999`)
-/// or an IP-only string (e.g., "127.0.0.1" or "2001:db8::1"). When an IP-only
-/// string is given, the default P2P port for the configured network is used.
+/// Accepts socket addresses with or without port. When no port is specified,
+/// the default P2P port for the configured network is used.
+///
+/// Supported formats:
+/// - IP with port: `192.168.1.1:9999`, `[::1]:19999`
+/// - IP without port: `127.0.0.1`, `2001:db8::1`
+/// - Hostname with port: `node.example.com:9999`
+/// - Hostname without port: `node.example.com`
 ///
 /// # Safety
 /// - `config` must be a valid pointer to an FFIClientConfig created by dash_spv_ffi_config_new/mainnet/testnet
@@ -158,26 +163,26 @@ pub unsafe extern "C" fn dash_spv_ffi_config_add_peer(
         }
     };
 
-    // 1) Try parsing as full SocketAddr first (handles IPv6 [::1]:port forms)
-    if let Ok(sock) = addr_str.parse::<SocketAddr>() {
-        cfg.peers.push(sock);
-        return FFIErrorCode::Success as i32;
-    }
-
-    // 2) If that fails, try parsing as bare IP address and apply default port
+    // Try parsing as bare IP address and apply default port
     if let Ok(ip) = addr_str.parse::<IpAddr>() {
         let sock = SocketAddr::new(ip, default_port);
         cfg.peers.push(sock);
         return FFIErrorCode::Success as i32;
     }
 
-    // 3) Optionally attempt DNS name with explicit port only; if no port, reject
-    if !addr_str.contains(':') {
-        set_last_error("Missing port for hostname; supply 'host:port' or IP only");
+    // If not, must be a hostname - reject empty or missing hostname
+    if addr_str.is_empty() || addr_str.starts_with(':') {
+        set_last_error("Empty or missing hostname");
         return FFIErrorCode::InvalidArgument as i32;
     }
 
-    match addr_str.to_socket_addrs() {
+    let addr_with_port = if addr_str.contains(':') {
+        addr_str.to_string()
+    } else {
+        format!("{}:{}", addr_str, default_port)
+    };
+
+    match addr_with_port.to_socket_addrs() {
         Ok(mut iter) => match iter.next() {
             Some(sock) => {
                 cfg.peers.push(sock);

dash-spv-ffi/tests/unit/test_configuration.rs

@@ -54,20 +54,26 @@ mod tests {
 
             // Test various invalid addresses
             let invalid_addrs = [
-                "not-an-ip:9999",
-                "256.256.256.256:9999",
-                "127.0.0.1:99999", // port too high
-                "127.0.0.1:-1",    // negative port
-                "localhost",       // hostname without port should be rejected
-                ":9999",           // missing IP
-                ":::",             // invalid IPv6
-                "localhost:abc",   // non-numeric port
+                "",                     // empty string
+                "256.256.256.256:9999", // invalid IP octets
+                "127.0.0.1:99999",      // port too high
+                "127.0.0.1:-1",         // negative port
+                ":9999",                // missing hostname
+                "localhost:",           // missing port
+                ":",                    // missing hostname and port
+                ":::",                  // invalid IPv6
+                "localhost:abc",        // non-numeric port
             ];
 
             for addr in &invalid_addrs {
                 let c_addr = CString::new(*addr).unwrap();
                 let result = dash_spv_ffi_config_add_peer(config, c_addr.as_ptr());
-                assert_eq!(result, FFIErrorCode::InvalidArgument as i32);
+                assert_eq!(
+                    result,
+                    FFIErrorCode::InvalidArgument as i32,
+                    "Expected '{}' to be invalid",
+                    addr
+                );
 
                 // Check error message
                 let error_ptr = dash_spv_ffi_get_last_error();
@@ -80,8 +86,10 @@ mod tests {
                 "192.168.1.1:8333",
                 "[::1]:9999",
                 "[2001:db8::1]:8333",
-                "127.0.0.1",   // IP-only v4
-                "2001:db8::1", // IP-only v6
+                "127.0.0.1",      // IP-only v4
+                "2001:db8::1",    // IP-only v6
+                "localhost:9999", // Hostname with port
+                "localhost",      // Hostname without port (uses default)
             ];
 
             for addr in &valid_addrs {