General utility for parsing DNS records

This is a utility for parsing and DNS records into structured data and a generic
container for DNS records of any type.

BUG=233821

Review URL: https://chromiumcodereview.appspot.com/14377002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@197798 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 131 insertions, 0 deletions

diff --git a/net/dns/record_rdata.cc b/net/dns/record_rdata.cc
new file mode 100644
index 0000000..1de3a4c
--- /dev/null
+++ b/net/dns/record_rdata.cc
@@ -0,0 +1,131 @@
+// Copyright (c) 2013 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/record_rdata.h"
+
+#include "net/base/big_endian.h"
+#include "net/base/dns_util.h"
+#include "net/dns/dns_protocol.h"
+#include "net/dns/dns_response.h"
+
+namespace net {
+
+static const size_t kSrvRecordMinimumSize = 6;
+
+RecordRdata::RecordRdata() {
+}
+
+SrvRecordRdata::SrvRecordRdata() : priority_(0), weight_(0), port_(0) {
+}
+
+SrvRecordRdata::~SrvRecordRdata() {}
+
+// static
+scoped_ptr<SrvRecordRdata> SrvRecordRdata::Create(
+    const base::StringPiece& data,
+    const DnsRecordParser& parser) {
+  if (data.size() < kSrvRecordMinimumSize) return scoped_ptr<SrvRecordRdata>();
+
+  scoped_ptr<SrvRecordRdata> rdata(new SrvRecordRdata);
+
+  BigEndianReader reader(data.data(), data.size());
+  // 2 bytes for priority, 2 bytes for weight, 2 bytes for port.
+  reader.ReadU16(&rdata->priority_);
+  reader.ReadU16(&rdata->weight_);
+  reader.ReadU16(&rdata->port_);
+
+  if (!parser.ReadName(data.substr(kSrvRecordMinimumSize).begin(),
+                       &rdata->target_))
+    return scoped_ptr<SrvRecordRdata>();
+
+  return rdata.Pass();
+}
+
+ARecordRdata::ARecordRdata() {
+}
+
+ARecordRdata::~ARecordRdata() {
+}
+
+// static
+scoped_ptr<ARecordRdata> ARecordRdata::Create(
+    const base::StringPiece& data,
+    const DnsRecordParser& parser) {
+  if (data.size() != kIPv4AddressSize)
+    return scoped_ptr<ARecordRdata>();
+
+  scoped_ptr<ARecordRdata> rdata(new ARecordRdata);
+
+  rdata->address_.resize(kIPv4AddressSize);
+  for (unsigned i = 0; i < kIPv4AddressSize; ++i) {
+    rdata->address_[i] = data[i];
+  }
+
+  return rdata.Pass();
+}
+
+CnameRecordRdata::CnameRecordRdata() {
+}
+
+CnameRecordRdata::~CnameRecordRdata() {
+}
+
+// static
+scoped_ptr<CnameRecordRdata> CnameRecordRdata::Create(
+    const base::StringPiece& data,
+    const DnsRecordParser& parser) {
+  scoped_ptr<CnameRecordRdata> rdata(new CnameRecordRdata);
+
+  if (!parser.ReadName(data.begin(), &rdata->cname_))
+    return scoped_ptr<CnameRecordRdata>();
+
+  return rdata.Pass();
+}
+
+PtrRecordRdata::PtrRecordRdata() {
+}
+
+PtrRecordRdata::~PtrRecordRdata() {
+}
+
+// static
+scoped_ptr<PtrRecordRdata> PtrRecordRdata::Create(
+    const base::StringPiece& data,
+    const DnsRecordParser& parser) {
+  scoped_ptr<PtrRecordRdata> rdata(new PtrRecordRdata);
+
+  if (!parser.ReadName(data.begin(), &rdata->ptrdomain_))
+    return scoped_ptr<PtrRecordRdata>();
+
+  return rdata.Pass();
+}
+
+TxtRecordRdata::TxtRecordRdata() {
+}
+
+TxtRecordRdata::~TxtRecordRdata() {
+}
+
+// static
+scoped_ptr<TxtRecordRdata> TxtRecordRdata::Create(
+    const base::StringPiece& data,
+    const DnsRecordParser& parser) {
+  scoped_ptr<TxtRecordRdata> rdata(new TxtRecordRdata);
+
+  for (size_t i = 0; i < data.size(); ) {
+    uint8 length = data[i];
+
+    if (i + length >= data.size())
+      return scoped_ptr<TxtRecordRdata>();
+
+    rdata->texts_.push_back(data.substr(i + 1, length).as_string());
+
+    // Move to the next string.
+    i += length + 1;
+  }
+
+  return rdata.Pass();
+}
+
+}  // namespace net