-adding libidn--towards fixing #2475

2 files changed, 30 insertions, 1 deletions

diff --git a/src/dns/Makefile.am b/src/dns/Makefile.am
index 6e543e07f..42d0c5bd1 100644
--- a/src/dns/Makefile.am
+++ b/src/dns/Makefile.am
@@ -83,7 +83,8 @@ gnunet_service_dns_DEPENDENCIES = \
 libgnunetdnsparser_la_SOURCES = \
  dnsparser.c 
 libgnunetdnsparser_la_LIBADD = \
- $(top_builddir)/src/util/libgnunetutil.la $(XLIB)
+ $(top_builddir)/src/util/libgnunetutil.la $(XLIB) \
+  -lidn
 libgnunetdnsparser_la_LDFLAGS = \
   $(GN_LIB_LDFLAGS) \
   -version-info 0:0:0
diff --git a/src/dns/dnsparser.c b/src/dns/dnsparser.c
index 4b0c03a77..c61c78164 100644
--- a/src/dns/dnsparser.c
+++ b/src/dns/dnsparser.c
@@ -25,11 +25,39 @@
  * @author Christian Grothoff
  */
 #include "platform.h"
+#include <idna.h>
+#if WINDOWS
+#include <idn-free.h>
+#endif
 #include "gnunet_util_lib.h"
 #include "gnunet_dnsparser_lib.h"
 #include "dnsparser.h"
 
 
+/**
+ * Check if a label in UTF-8 format can be coded into valid IDNA.
+ * This can fail if the ASCII-conversion becomes longer than 63 characters.
+ *
+ * @param label label to check (UTF-8 string)
+ * @return GNUNET_OK if the label can be converted to IDNA,
+ *         GNUNET_SYSERR if the label is not valid for DNS names
+ */
+int
+GNUNET_DNSPARSER_check_label (const char *label)
+{
+  char *output;
+  
+  if (IDNA_SUCCESS != 
+      idna_to_ascii_8z (label, &output, IDNA_USE_STD3_ASCII_RULES))
+    return GNUNET_SYSERR;
+#if WINDOWS
+  idn_free (output);
+#else
+  free (output);
+#endif
+  return GNUNET_OK;
+}
+
 
 /**
  * Parse name inside of a DNS query or record.