Finished DNS-SD server. Finished Privet-specified DNS-SD server.

cloud_print/gcp20/prototype/dns_response_builder.cc

Index: cloud_print/gcp20/prototype/dns_response_builder.cc
diff --git a/cloud_print/gcp20/prototype/dns_response_builder.cc b/cloud_print/gcp20/prototype/dns_response_builder.cc
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+++ b/cloud_print/gcp20/prototype/dns_response_builder.cc
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+// Copyright 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 "cloud_print/gcp20/prototype/dns_response_builder.h"
+
+#include "base/logging.h"
+#include "net/base/big_endian.h"
+#include "net/base/dns_util.h"
+#include "net/base/ip_endpoint.h"
+
+namespace {
+
+uint16 klass = net::dns_protocol::kClassIN;
+
+}  // namespace
+
+DnsResponseRecord::DnsResponseRecord() : type(0), klass(0), ttl(0) {
+}
+
+DnsResponseRecord::~DnsResponseRecord() {
+}
+
+DnsResponseBuilder::DnsResponseBuilder(uint16 id) {
+  header_.id = id;
+  // TODO(maksymb): Check do we need AA flag enabled.
+  header_.flags = net::dns_protocol::kFlagResponse |
+                  net::dns_protocol::kFlagAA;
+  header_.qdcount = 0;
+  header_.ancount = 0;
+  header_.nscount = 0;
+  header_.arcount = 0;
+}
+
+void DnsResponseBuilder::AppendPtr(const std::string& service_type, uint32 ttl,
+                                   const std::string& service_name) {
+  std::string rdata;
+  bool success = net::DNSDomainFromDot(service_name, &rdata);
+  DCHECK(success);
+
+  AddResponse(service_type, net::dns_protocol::kTypePTR, ttl, rdata);
+}
+
+void DnsResponseBuilder::AppendSrv(const std::string& service_name, uint32 ttl,
+                                   uint16 priority, uint16 weight,
+                                   uint16 http_port,
+                                   const std::string& service_domain_name) {
+  std::string domain_name;
+  bool success = net::DNSDomainFromDot(service_domain_name, &domain_name);
+  DCHECK(success);
+
+  std::vector<uint8> rdata(2 + 2 + 2 + domain_name.size());
+
+  net::BigEndianWriter writer(rdata.data(), rdata.size());
+  success = writer.WriteU16(priority) &&
+            writer.WriteU16(weight) &&
+            writer.WriteU16(http_port) &&
+            writer.WriteBytes(domain_name.data(), domain_name.size());
+  DCHECK(success);
+  DCHECK_EQ(writer.remaining(), 0);  // For warranty of correct size allocation.
+
+  AddResponse(service_name, net::dns_protocol::kTypeSRV, ttl,
+              std::string(rdata.begin(), rdata.end()));
+}
+
+void DnsResponseBuilder::AppendA(const std::string& service_domain_name,
+                                 uint32 ttl, net::IPAddressNumber http_ipv4) {
+  if (http_ipv4.empty()) {
+    LOG(ERROR) << "Invalid IP";
+    return;
+  }
+
+  AddResponse(service_domain_name, net::dns_protocol::kTypeA, ttl,
+              std::string(http_ipv4.begin(), http_ipv4.end()));
+}
+
+void DnsResponseBuilder::AppendTxt(const std::string& service_name, uint32 ttl,
+                                   const std::vector<std::string>& metadata) {
+  std::string rdata;
+  for (std::vector<std::string>::const_iterator str = metadata.begin();
+       str != metadata.end(); ++str) {
+    int len = static_cast<int>(str->size());
+    DCHECK_LT(len, 256);
+    rdata += static_cast<char>(len);  // Set length byte.
+    rdata += *str;
+  }
+
+  AddResponse(service_name, net::dns_protocol::kTypeTXT, ttl, rdata);
+}
+
+scoped_refptr<net::IOBufferWithSize> DnsResponseBuilder::Build() {
+  size_t size = sizeof(header_);
+  for (std::vector<DnsResponseRecord>::const_iterator iter = responses_.begin();
+       iter != responses_.end(); ++iter) {
+    size += iter->name.size() + 2 +  // Two dots: first and last.
+            sizeof(iter->type) + sizeof(iter->klass) + sizeof(iter->ttl) +
+            2 +  // sizeof(RDLENGTH)
+            iter->rdata.size();
+  }
+
+  if (responses_.empty())
+    return NULL;  // No answer.
+
+  header_.ancount = static_cast<uint16>(responses_.size());
+
+  scoped_refptr<net::IOBufferWithSize> message(
+      new net::IOBufferWithSize(static_cast<int>(size)));
+  net::BigEndianWriter writer(message->data(), message->size());
+  bool success = writer.WriteU16(header_.id) &&
+                 writer.WriteU16(header_.flags) &&
+                 writer.WriteU16(header_.qdcount) &&
+                 writer.WriteU16(header_.ancount) &&
+                 writer.WriteU16(header_.nscount) &&
+                 writer.WriteU16(header_.arcount);
+  DCHECK(success);
+
+  std::string name_in_dns_format;
+  for (std::vector<DnsResponseRecord>::const_iterator iter = responses_.begin();
+       iter != responses_.end(); ++iter) {
+    success = net::DNSDomainFromDot(iter->name, &name_in_dns_format);
+    DCHECK(success);
+    DCHECK_EQ(name_in_dns_format.size(), iter->name.size() + 2);
+
+    success = writer.WriteBytes(name_in_dns_format.data(),
+                                name_in_dns_format.size()) &&
+              writer.WriteU16(iter->type) &&
+              writer.WriteU16(iter->klass) &&
+              writer.WriteU32(iter->ttl) &&
+              writer.WriteU16(static_cast<uint16>(iter->rdata.size())) &&
+              writer.WriteBytes(iter->rdata.data(), iter->rdata.size());
+    DCHECK(success);
+  }
+
+  DCHECK_EQ(writer.remaining(), 0);  // For warranty of correct size allocation.
+
+  return message;
+}
+
+void DnsResponseBuilder::AddResponse(const std::string& name, uint16 type,
+                                     uint32 ttl, const std::string& rdata) {
+  DnsResponseRecord response;
+  response.name = name;
+  response.klass = klass;
+  response.ttl = ttl;
+  response.type = type;
+  response.rdata = rdata;
+  responses_.push_back(response);
+}
+