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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/big_endian.h"
#include "base/logging.h"
#include "net/base/dns_util.h"
#include "net/base/io_buffer.h"
#include "net/base/ip_endpoint.h"
#include "net/dns/dns_response.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;
}
DnsResponseBuilder::~DnsResponseBuilder() {
}
void DnsResponseBuilder::AppendPtr(const std::string& service_type,
uint32 ttl,
const std::string& service_name,
bool answer) {
std::string rdata;
bool success = net::DNSDomainFromDot(service_name, &rdata);
DCHECK(success);
AddResponse(service_type, net::dns_protocol::kTypePTR, ttl, rdata, answer);
}
void DnsResponseBuilder::AppendSrv(const std::string& service_name,
uint32 ttl,
uint16 priority,
uint16 weight,
uint16 http_port,
const std::string& service_domain_name,
bool answer) {
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());
base::BigEndianWriter writer(reinterpret_cast<char*>(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()), answer);
}
void DnsResponseBuilder::AppendA(const std::string& service_domain_name,
uint32 ttl,
net::IPAddressNumber http_ipv4,
bool answer) {
// TODO(maksymb): IP to send must depends on interface from where query was
// received.
if (http_ipv4.empty()) {
return;
}
AddResponse(service_domain_name, net::dns_protocol::kTypeA, ttl,
std::string(http_ipv4.begin(), http_ipv4.end()), answer);
}
void DnsResponseBuilder::AppendAAAA(const std::string& service_domain_name,
uint32 ttl,
net::IPAddressNumber http_ipv6,
bool answer) {
// TODO(maksymb): IP to send must depends on interface from where query was
// received.
if (http_ipv6.empty()) {
return;
}
AddResponse(service_domain_name, net::dns_protocol::kTypeAAAA, ttl,
std::string(http_ipv6.begin(), http_ipv6.end()), answer);
}
void DnsResponseBuilder::AppendTxt(const std::string& service_name,
uint32 ttl,
const std::vector<std::string>& metadata,
bool answer) {
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, answer);
}
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.
DCHECK_EQ(static_cast<size_t>(header_.ancount + header_.arcount),
responses_.size());
scoped_refptr<net::IOBufferWithSize> message(
new net::IOBufferWithSize(static_cast<int>(size)));
base::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,
bool answer) {
DnsResponseRecord response;
response.name = name;
response.klass = klass;
response.ttl = ttl;
response.type = type;
response.rdata = rdata;
if (answer) {
responses_.insert(responses_.begin() + header_.ancount, response);
++header_.ancount;
} else {
responses_.push_back(response);
++header_.arcount;
}
}
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