From e70ec38000404de1c871d835a6e35dbfcc47884d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Wed, 5 Aug 2020 11:21:48 +0300
Subject: [PATCH] srt: Add support for using hostnames instead of IP addresses

If an address can't be parsed as IP address, try resolving it via
GResolver instead. SRT URIs more often than not contain hostnames and
without trying to resolve them we won't be able to handle such URIs.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1493>
---
 ext/srt/gstsrtobject.c | 80 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 69 insertions(+), 11 deletions(-)

diff --git a/ext/srt/gstsrtobject.c b/ext/srt/gstsrtobject.c
index acd4694f51..7f558cf635 100644
--- a/ext/srt/gstsrtobject.c
+++ b/ext/srt/gstsrtobject.c
@@ -125,6 +125,56 @@ static struct srt_constant_params srt_params[] = {
 
 static gint srt_init_refcount = 0;
 
+static GSocketAddress *
+gst_srt_object_resolve (GstSRTObject * srtobject, const gchar * address,
+    guint port, GCancellable * cancellable, GError ** err_out)
+{
+  GError *err = NULL;
+  GSocketAddress *saddr;
+  GResolver *resolver;
+
+  saddr = g_inet_socket_address_new_from_string (address, port);
+  if (!saddr) {
+    GList *results;
+
+    GST_DEBUG_OBJECT (srtobject->element, "resolving IP address for host %s",
+        address);
+    resolver = g_resolver_get_default ();
+    results = g_resolver_lookup_by_name (resolver, address, cancellable, &err);
+    if (!results)
+      goto name_resolve;
+
+    saddr = g_inet_socket_address_new (G_INET_ADDRESS (results->data), port);
+
+    g_resolver_free_addresses (results);
+    g_object_unref (resolver);
+  }
+#ifndef GST_DISABLE_GST_DEBUG
+  {
+    gchar *ip =
+        g_inet_address_to_string (g_inet_socket_address_get_address
+        (G_INET_SOCKET_ADDRESS (saddr)));
+
+    GST_DEBUG_OBJECT (srtobject->element, "IP address for host %s is %s",
+        address, ip);
+    g_free (ip);
+  }
+#endif
+
+  return saddr;
+
+name_resolve:
+  {
+    GST_WARNING_OBJECT (srtobject->element, "Failed to resolve %s: %s", address,
+        err->message);
+    g_set_error (err_out, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_OPEN_READ,
+        "Failed to resolve host '%s': %s", address, err->message);
+    g_clear_error (&err);
+    g_object_unref (resolver);
+    return NULL;
+  }
+}
+
 static gboolean
 gst_srt_object_set_common_params (SRTSOCKET sock, GstSRTObject * srtobject,
     GError ** error)
@@ -779,7 +829,7 @@ gst_srt_object_wait_connect (GstSRTObject * srtobject,
   GSocketFamily bind_sa_family;
   gpointer bind_sa;
   gsize bind_sa_len;
-  GSocketAddress *bind_addr;
+  GSocketAddress *bind_addr = NULL;
 
   GST_OBJECT_LOCK (srtobject->element);
 
@@ -792,7 +842,13 @@ gst_srt_object_wait_connect (GstSRTObject * srtobject,
 
   GST_OBJECT_UNLOCK (srtobject->element);
 
-  bind_addr = g_inet_socket_address_new_from_string (local_address, local_port);
+  bind_addr =
+      gst_srt_object_resolve (srtobject, local_address, local_port, cancellable,
+      error);
+  if (!bind_addr) {
+    goto failed;
+  }
+
   bind_sa_len = g_socket_address_get_native_size (bind_addr);
   bind_sa = g_alloca (bind_sa_len);
   bind_sa_family = g_socket_address_get_family (bind_addr);
@@ -869,7 +925,7 @@ failed:
 }
 
 static gboolean
-gst_srt_object_connect (GstSRTObject * srtobject,
+gst_srt_object_connect (GstSRTObject * srtobject, GCancellable * cancellable,
     GstSRTConnectionMode connection_mode, GSocketFamily sa_family, gpointer sa,
     size_t sa_len, GError ** error)
 {
@@ -930,8 +986,12 @@ gst_srt_object_connect (GstSRTObject * srtobject,
     gsize bind_sa_len;
 
     GSocketAddress *bind_addr =
-        g_inet_socket_address_new_from_string (local_address,
-        local_port);
+        gst_srt_object_resolve (srtobject, local_address,
+        local_port, cancellable, error);
+
+    if (!bind_addr) {
+      goto failed;
+    }
 
     bind_sa_len = g_socket_address_get_native_size (bind_addr);
     bind_sa = g_alloca (bind_sa_len);
@@ -999,8 +1059,8 @@ gst_srt_object_open_connection (GstSRTObject * srtobject,
         sa_len, error);
   } else {
     ret =
-        gst_srt_object_connect (srtobject, connection_mode, sa_family, sa,
-        sa_len, error);
+        gst_srt_object_connect (srtobject, cancellable, connection_mode,
+        sa_family, sa, sa_len, error);
   }
 
   return ret;
@@ -1048,11 +1108,9 @@ gst_srt_object_open_internal (GstSRTObject * srtobject,
 
   GST_OBJECT_UNLOCK (srtobject->element);
 
-  socket_address = g_inet_socket_address_new_from_string (addr_str, port);
-
+  socket_address =
+      gst_srt_object_resolve (srtobject, addr_str, port, cancellable, error);
   if (socket_address == NULL) {
-    g_set_error (error, GST_RESOURCE_ERROR, GST_RESOURCE_ERROR_OPEN_READ,
-        "Invalid host");
     goto out;
   }