1 files changed, 85 insertions, 0 deletions
diff --git a/net/dns/dns_util.cc b/net/dns/dns_util.cc
new file mode 100644
index 0000000..7ab60c6
--- /dev/null
+++ b/net/dns/dns_util.cc
@@ -0,0 +1,85 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/dns/dns_util.h"
+
+#include <cstring>
+
+namespace net {
+
+// Based on DJB's public domain code.
+bool DNSDomainFromDot(const base::StringPiece& dotted, std::string* out) {
+  const char* buf = dotted.data();
+  unsigned n = dotted.size();
+  char label[63];
+  size_t labellen = 0; /* <= sizeof label */
+  char name[255];
+  size_t namelen = 0; /* <= sizeof name */
+  char ch;
+
+  for (;;) {
+    if (!n)
+      break;
+    ch = *buf++;
+    --n;
+    if (ch == '.') {
+      // Don't allow empty labels per http://crbug.com/456391.
+      if (!labellen)
+        return false;
+      if (namelen + labellen + 1 > sizeof name)
+        return false;
+      name[namelen++] = static_cast<char>(labellen);
+      memcpy(name + namelen, label, labellen);
+      namelen += labellen;
+      labellen = 0;
+      continue;
+    }
+    if (labellen >= sizeof label)
+      return false;
+    label[labellen++] = ch;
+  }
+
+  // Allow empty label at end of name to disable suffix search.
+  if (labellen) {
+    if (namelen + labellen + 1 > sizeof name)
+      return false;
+    name[namelen++] = static_cast<char>(labellen);
+    memcpy(name + namelen, label, labellen);
+    namelen += labellen;
+    labellen = 0;
+  }
+
+  if (namelen + 1 > sizeof name)
+    return false;
+  if (namelen == 0) // Empty names e.g. "", "." are not valid.
+    return false;
+  name[namelen++] = 0;  // This is the root label (of length 0).
+
+  *out = std::string(name, namelen);
+  return true;
+}
+
+std::string DNSDomainToString(const base::StringPiece& domain) {
+  std::string ret;
+
+  for (unsigned i = 0; i < domain.size() && domain[i]; i += domain[i] + 1) {
+#if CHAR_MIN < 0
+    if (domain[i] < 0)
+      return std::string();
+#endif
+    if (domain[i] > 63)
+      return std::string();
+
+    if (i)
+      ret += ".";
+
+    if (static_cast<unsigned>(domain[i]) + i + 1 > domain.size())
+      return std::string();
+
+    domain.substr(i + 1, domain[i]).AppendToString(&ret);
+  }
+  return ret;
+}
+
+}  // namespace net