feat: connection type callback (#8)

`endpoint_conn_type_cb` to be able to react to connection type changes on a connection to a specific node id

Author: ramfox

Cargo.toml

@@ -30,6 +30,7 @@ tokio = { version = "1.36.0", features = ["rt-multi-thread"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 url = "2.5.0"
+futures-lite = "2.3.0"
 
 [features]
 # generate headers

irohnet.h

@@ -102,6 +102,10 @@ enum EndpointResult {
      *  It is common to simply log this error and move on.
      */
     ENDPOINT_RESULT_INCOMING_ERROR,
+    /** \brief
+     *  Unable to find connection for the given `NodeId`
+     */
+    ENDPOINT_RESULT_CONNECTION_TYPE_ERROR,
 }
 #ifndef DOXYGEN
 ; typedef uint8_t
@@ -513,6 +517,55 @@ typedef struct PublicKey {
     uint8_32_array_t key;
 } PublicKey_t;
 
+/** <No documentation available> */
+/** \remark Has the same ABI as `uint8_t` **/
+#ifdef DOXYGEN
+typedef
+#endif
+enum ConnectionType {
+    /** \brief
+     *  Direct UDP connection
+     */
+    CONNECTION_TYPE_DIRECT = 0,
+    /** \brief
+     *  Relay connection over relay
+     */
+    CONNECTION_TYPE_RELAY,
+    /** \brief
+     *  Both a UDP and a relay connection are used.
+     *
+     *  This is the case if we do have a UDP address, but are missing a recent confirmation that
+     *  the address works.
+     */
+    CONNECTION_TYPE_MIXED,
+    /** \brief
+     *  We have no verified connection to this PublicKey
+     */
+    CONNECTION_TYPE_NONE,
+}
+#ifndef DOXYGEN
+; typedef uint8_t
+#endif
+ConnectionType_t;
+
+/** \brief
+ *  Run a callback once you have a direct connection to a peer
+ *
+ *  Does not block. The provided callback will be called when we have a direct
+ *  connection to the peer associated with the `node_id`, or the timeout has occurred.
+ *
+ *  To wait indefinitely, provide -1 for the timeout parameter.
+ *
+ *  `ctx` is passed along to the callback, to allow passing context, it must be thread safe as the callback is
+ *  called from another thread.
+ */
+void
+endpoint_conn_type_cb (
+    Endpoint_t * ep,
+    void const * ctx,
+    PublicKey_t const * node_id,
+    void (*cb)(void const *, EndpointResult_t, ConnectionType_t));
+
 /** \brief
  *  Represents a valid URL.
  */

main.c

@@ -254,6 +254,24 @@ run_server (EndpointConfig_t * config, slice_ref_uint8_t alpn_slice, bool json_o
   return 0;
 }
 
+typedef struct ConnectionStatus {
+  EndpointResult_t res;
+  ConnectionType_t conn_type;
+} ConnectionStatus;
+
+void
+callback(
+  void const * ctx,
+  EndpointResult_t res,
+  ConnectionType_t conn_type
+)
+{
+  ConnectionStatus *cs;
+  cs = (ConnectionStatus *)ctx;
+  cs->res = res;
+  cs->conn_type = conn_type;
+}
+
 int
 run_client (
   EndpointConfig_t * config,
@@ -315,6 +333,10 @@ run_client (
     return -1;
   }
 
+  ConnectionStatus *conn_status;
+  conn_status = malloc(sizeof(ConnectionStatus));
+  endpoint_conn_type_cb(ep, (const void *)conn_status, &node_addr.node_id, callback);
+
   SendStream_t * send_stream = send_stream_default();
   ret = connection_open_uni(&conn, &send_stream);
   if (ret != 0) {
@@ -389,6 +411,29 @@ run_client (
   printf("received: '%s'\n", recv_str);
 
   fflush(stdout);
+  // check that we were able to use the conn_type callback
+  if (conn_status->res != ENDPOINT_RESULT_OK) {
+    fprintf(stderr, "callback failed to send a connection type\n");
+    return -1;
+  } else {
+    switch (conn_status->conn_type) {
+      case CONNECTION_TYPE_DIRECT:
+        printf("had a direct connection\n");
+        break;
+      case CONNECTION_TYPE_RELAY:
+        printf("had a relay connection\n");
+        break;
+      case CONNECTION_TYPE_MIXED:
+        printf("had a mixed connection\n");
+        break;
+      case CONNECTION_TYPE_NONE:
+        fprintf(stderr, "callback reported no connection\n");
+        return -1;
+      default:
+        fprintf(stderr, "unknown connection type reported: %i\n", conn_status->conn_type);
+        return -1;
+    }
+  }
 
   // finish
   ret = send_stream_finish(send_stream);
@@ -413,6 +458,7 @@ run_client (
   // cleanup
   free(recv_str);
   free(recv_buffer);
+  free(conn_status);
   recv_stream_free(recv_stream);
   return 0;
 }