From 2ad934742422ecb63fe3fafdc8c73d067a9e2fb7 Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Fri, 24 Mar 2017 18:17:50 +0100
Subject: implement GNUNET_NETWORK_test_port_free() for testcases to
 conveniently check if a port is available

---
 src/include/gnunet_network_lib.h | 12 +++++++++
 src/util/network.c               | 58 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/src/include/gnunet_network_lib.h b/src/include/gnunet_network_lib.h
index beca83807..d9d3d90e7 100644
--- a/src/include/gnunet_network_lib.h
+++ b/src/include/gnunet_network_lib.h
@@ -588,6 +588,18 @@ void
 GNUNET_NETWORK_fdset_destroy (struct GNUNET_NETWORK_FDSet *fds);
 
 
+/**
+ * Test if the given @a port is available.
+ *
+ * @param ipproto transport protocol to test (i.e. IPPROTO_TCP)
+ * @param port port number to test
+ * @return #GNUNET_OK if the port is available, #GNUNET_NO if not
+ */
+int
+GNUNET_NETWORK_test_port_free (int ipproto,
+			       uint16_t port);
+
+
 #if 0                           /* keep Emacsens' auto-indent happy */
 {
 #endif
diff --git a/src/util/network.c b/src/util/network.c
index c82caafd9..66a468e45 100644
--- a/src/util/network.c
+++ b/src/util/network.c
@@ -1697,6 +1697,64 @@ initialize_select_thread ()
 
 #endif
 
+/**
+ * Test if the given @a port is available.
+ *
+ * @param ipproto transport protocol to test (i.e. IPPROTO_TCP)
+ * @param port port number to test
+ * @return #GNUNET_OK if the port is available, #GNUNET_NO if not
+ */
+int
+GNUNET_NETWORK_test_port_free (int ipproto,
+			       uint16_t port)
+{
+  struct GNUNET_NETWORK_Handle *socket;
+  int bind_status;
+  int socktype;
+  char open_port_str[6];
+  struct addrinfo hint;
+  struct addrinfo *ret;
+  struct addrinfo *ai;
+
+  GNUNET_snprintf (open_port_str,
+		   sizeof (open_port_str),
+		   "%u",
+		   (unsigned int) port);
+  socktype = (IPPROTO_TCP == ipproto)
+    ? SOCK_STREAM
+    : SOCK_DGRAM;
+  ret = NULL;
+  memset (&hint, 0, sizeof (hint));
+  hint.ai_family = AF_UNSPEC;	/* IPv4 and IPv6 */
+  hint.ai_socktype = socktype;
+  hint.ai_protocol = ipproto;
+  hint.ai_addrlen = 0;
+  hint.ai_addr = NULL;
+  hint.ai_canonname = NULL;
+  hint.ai_next = NULL;
+  hint.ai_flags = AI_PASSIVE | AI_NUMERICSERV;	/* Wild card address */
+  GNUNET_assert (0 == getaddrinfo (NULL,
+				   open_port_str,
+				   &hint,
+				   &ret));
+  for (ai = ret; NULL != ai; ai = ai->ai_next)
+  {
+    socket = GNUNET_NETWORK_socket_create (ai->ai_family,
+					   ai->ai_socktype,
+					   ai->ai_protocol);
+    if (NULL == socket)
+      continue;
+    bind_status = GNUNET_NETWORK_socket_bind (socket,
+					      ai->ai_addr,
+					      ai->ai_addrlen);
+    GNUNET_NETWORK_socket_close (socket);
+    if (GNUNET_OK != bind_status)
+      break;
+  }
+  freeaddrinfo (ret);
+  return bind_status;
+}
+
 
 #ifndef MINGW
 /**
-- 
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