net/local: add local_peerconn helper

Change-Id: I2cbceb68f709c581bc0b878844dd16efcd76d4a7
Signed-off-by: chao.an <anchao@xiaomi.com>

net/local/local.h

@@ -259,6 +259,19 @@ void local_free(FAR struct local_conn_s *conn);
 
 FAR struct local_conn_s *local_nextconn(FAR struct local_conn_s *conn);
 
+/****************************************************************************
+ * Name: local_peerconn
+ *
+ * Description:
+ *   Traverse the connections list to find the peer
+ *
+ * Assumptions:
+ *   This function must be called with the network locked.
+ *
+ ****************************************************************************/
+
+FAR struct local_conn_s *local_peerconn(FAR struct local_conn_s *conn);
+
 /****************************************************************************
  * Name: psock_local_bind
  *

net/local/local_conn.c

@@ -82,6 +82,33 @@ FAR struct local_conn_s *local_nextconn(FAR struct local_conn_s *conn)
 #endif
 }
 
+/****************************************************************************
+ * Name: local_peerconn
+ *
+ * Description:
+ *   Traverse the connections list to find the peer
+ *
+ * Assumptions:
+ *   This function must be called with the network locked.
+ *
+ ****************************************************************************/
+
+FAR struct local_conn_s *local_peerconn(FAR struct local_conn_s *conn)
+{
+  FAR struct local_conn_s *peer = NULL;
+
+  while ((peer = local_nextconn(peer)) != NULL)
+    {
+      if (conn->lc_proto == peer->lc_proto && conn != peer &&
+          !strncmp(conn->lc_path, peer->lc_path, UNIX_PATH_MAX - 1))
+        {
+          return peer;
+        }
+    }
+
+  return NULL;
+}
+
 /****************************************************************************
  * Name: local_alloc()
  *