// Copyright (C) 2012  Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

#include <exceptions/exceptions.h>

#include <util/buffer.h>

#include <dns/name.h>
#include <dns/labelsequence.h>
#include <dns/messagerenderer.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rrclass.h>
#include <dns/rrtype.h>

#include <datasrc/memory/rdata_encoder.h>

#include <util/unittests/wiredata.h>

#include <gtest/gtest.h>

#include <boost/bind.hpp>
#include <boost/foreach.hpp>

#include <cstring>
#include <set>
#include <string>
#include <vector>

using namespace isc::dns;
using namespace isc::dns::rdata;
using namespace isc::datasrc::memory;
using namespace isc::datasrc::memory::testing;

using isc::util::unittests::matchWireData;
using std::string;
using std::vector;

namespace {
// This defines a tuple of test data used in test_rdata_list below.
struct TestRdata {
    const char* const rrclass;  // RR class, textual form
    const char* const rrtype;   // RR type, textual form
    const char* const rdata;    // textual RDATA
    const size_t n_varlen_fields; // expected # of variable-len fields
};

// This test data consist of (almost) all supported types of RDATA (+ some
// unusual and corner cases).
const TestRdata test_rdata_list[] = {
    {"IN", "A", "192.0.2.1", 0},
    {"IN", "NS", "ns.example.com", 0},
    {"IN", "CNAME", "cname.example.com", 0},
    {"IN", "SOA", "ns.example.com root.example.com 0 0 0 0 0", 0},
    {"IN", "PTR", "reverse.example.com", 0},
    {"IN", "HINFO", "\"cpu-info\" \"OS-info\"", 1},
    {"IN", "MINFO", "root.example.com mbox.example.com", 0},
    {"IN", "MX", "10 mx.example.com", 0},
    {"IN", "TXT", "\"test1\" \"test 2\"", 1},
    {"IN", "RP", "root.example.com. rp-text.example.com", 0},
    {"IN", "AFSDB", "1 afsdb.example.com", 0},
    {"IN", "AAAA", "2001:db8::1", 0},
    {"IN", "SRV", "1 0 10 target.example.com", 0},
    {"IN", "NAPTR", "100 50 \"s\" \"http\" \"\" _http._tcp.example.com", 1},
    {"IN", "DNAME", "dname.example.com", 0},
    {"IN", "DS", "12892 5 2 5F0EB5C777586DE18DA6B5", 1},
    {"IN", "SSHFP", "1 1 dd465c09cfa51fb45020cc83316fff", 1},
    // We handle RRSIG separately, so it's excluded from the list
    {"IN", "NSEC", "next.example.com. A AAAA NSEC RRSIG", 1},
    {"IN", "DNSKEY", "256 3 5 FAKEFAKE", 1},
    {"IN", "DHCID", "FAKEFAKE", 1},
    {"IN", "NSEC3", "1 1 12 AABBCCDD FAKEFAKE A RRSIG", 1},
    {"IN", "NSEC3PARAM", "1 0 12 AABBCCDD", 1},
    {"IN", "SPF", "v=spf1 +mx a:colo.example.com/28 -all", 1},
    {"IN", "DLV", "12892 5 2 5F0EB5C777586DE18DA6B5", 1},
    {"IN", "TYPE65000", "\\# 3 010203", 1}, // some "custom" type
    {"IN", "TYPE65535", "\\# 0", 1},        // max RR type, 0-length RDATA
    {"CH", "A", "\\# 2 0102", 1}, // A RR for non-IN class; varlen data
    {"CH", "NS", "ns.example.com", 0}, // class CH, generic data
    {"CH", "TXT", "BIND10", 1},        // ditto
    {"HS", "A", "\\# 5 0102030405", 1}, // A RR for non-IN class; varlen data
    {NULL, NULL, NULL, 0}
};

// The following two functions will be used to generate wire format data
// from encoded representation of each RDATA.
void
renderNameField(MessageRenderer* renderer, bool additional_required,
                const LabelSequence& labels, RdataNameAttributes attributes)
{
    EXPECT_EQ(additional_required,
              (attributes & NAMEATTR_ADDITIONAL) != 0);
    renderer->writeName(labels, (attributes & NAMEATTR_COMPRESSIBLE) != 0);
}

void
renderDataField(MessageRenderer* renderer, const uint8_t* data,
                size_t data_len)
{
    renderer->writeData(data, data_len);
}

class RdataEncoderTest : public ::testing::Test {
protected:
    RdataEncoderTest() : a_rdata_(createRdata(RRType::A(), RRClass::IN(),
                                              "192.0.2.53")),
                         aaaa_rdata_(createRdata(RRType::AAAA(), RRClass::IN(),
                                                 "2001:db8::53")),
                         rrsig_rdata_(createRdata(
                                          RRType::RRSIG(), RRClass::IN(),
                                          "A 5 2 3600 20120814220826 "
                                          "20120715220826 12345 com. FAKE"))
    {}

    // This helper test method constructs encodes the given list of RDATAs
    // (in rdata_list), and then iterates over the data, rendering the fields
    // in the wire format.  It then compares the wire data with the one
    // generated by the normal libdns++ interface to see the encoding/decoding
    // works as intended.
    void checkEncode(RRClass rrclass, RRType rrtype,
                     const vector<ConstRdataPtr>& rdata_list,
                     size_t expected_varlen_fields,
                     const vector<ConstRdataPtr>& rrsig_list);

    void addRdataCommon(const vector<ConstRdataPtr>& rrsigs);
    void addRdataMultiCommon(const vector<ConstRdataPtr>& rrsigs);

    // Some commonly used RDATA
    const ConstRdataPtr a_rdata_;
    const ConstRdataPtr aaaa_rdata_;
    const ConstRdataPtr rrsig_rdata_;

    RdataEncoder encoder_;
    vector<uint8_t> encoded_data_;
    MessageRenderer expected_renderer_;
    MessageRenderer actual_renderer_;
    vector<ConstRdataPtr> rdata_list_;
};

void
RdataEncoderTest::checkEncode(RRClass rrclass, RRType rrtype,
                              const vector<ConstRdataPtr>& rdata_list,
                              size_t expected_varlen_fields,
                              const vector<ConstRdataPtr>& rrsig_list =
                              vector<ConstRdataPtr>())
{
    // These two names will be rendered before and after the test RDATA,
    // to check in case the RDATA contain a domain name whether it's
    // compressed or not correctly.  The names in the RDATA should basically
    // a subdomain of example.com, so it can be compressed due to dummy_name.
    // Likewise, dummy_name2 should be able to be fully compressed due to
    // the name in the RDATA.
    const Name dummy_name("com");
    const Name dummy_name2("example.com");

    // The set of RR types that require additional section processing.
    // We'll pass it to renderNameField to check the stored attribute matches
    // our expectation.
    std::set<RRType> need_additionals;
    need_additionals.insert(RRType::NS());
    need_additionals.insert(RRType::MX());
    need_additionals.insert(RRType::SRV());
    expected_renderer_.clear();
    actual_renderer_.clear();
    encoded_data_.clear();

    const bool additional_required =
        (need_additionals.find(rrtype) != need_additionals.end());

    // Build expected wire-format data
    expected_renderer_.writeName(dummy_name);
    BOOST_FOREACH(const ConstRdataPtr& rdata, rdata_list) {
        rdata->toWire(expected_renderer_);
    }
    expected_renderer_.writeName(dummy_name2);
    BOOST_FOREACH(const ConstRdataPtr& rdata, rrsig_list) {
        rdata->toWire(expected_renderer_);
    }

    // Then build wire format data using the encoded data.
    // 1st dummy name
    actual_renderer_.writeName(dummy_name);

    // Create encoded data
    encoder_.start(rrclass, rrtype);
    BOOST_FOREACH(const ConstRdataPtr& rdata, rdata_list) {
        encoder_.addRdata(*rdata);
    }
    BOOST_FOREACH(const ConstRdataPtr& rdata, rrsig_list) {
        encoder_.addSIGRdata(*rdata);
    }
    encoded_data_.resize(encoder_.getStorageLength());
    encoder_.encode(&encoded_data_[0], encoded_data_.size());

    // If this type of RDATA is expected to contain variable-length fields,
    // we brute force the encoded data, exploiting our knowledge of actual
    // encoding, then adjust the encoded data excluding the list of length
    // fields.  This is ugly, but we should be able to eliminate this hack
    // at #2096.
    vector<uint16_t> varlen_list;
    if (expected_varlen_fields > 0) {
        const size_t varlen_list_size =
            rdata_list.size() * expected_varlen_fields * sizeof(uint16_t);
        ASSERT_LE(varlen_list_size, encoded_data_.size());
        varlen_list.resize(rdata_list.size() * expected_varlen_fields);
        std::memcpy(&varlen_list[0], &encoded_data_[0], varlen_list_size);
        encoded_data_.assign(encoded_data_.begin() + varlen_list_size,
                             encoded_data_.end());
    }

    // If RRSIGs are given, we need to extract the list of the RRSIG lengths
    // and adjust encoded_data_ further (this will be unnecessary at #2096,
    // too).
    vector<uint16_t> rrsiglen_list;
    if (rrsig_list.size() > 0) {
        const size_t rrsig_len_size = rrsig_list.size() * sizeof(uint16_t);
        ASSERT_LE(rrsig_len_size, encoded_data_.size());
        rrsiglen_list.resize(rrsig_list.size() * rrsig_len_size);
        std::memcpy(&rrsiglen_list[0], &encoded_data_[0], rrsig_len_size);
        encoded_data_.assign(encoded_data_.begin() + rrsig_len_size,
                             encoded_data_.end());
    }

    // Create wire-format data from the encoded data
    foreachRdataField(rrclass, rrtype, rdata_list.size(), encoded_data_,
                      varlen_list,
                      boost::bind(renderNameField, &actual_renderer_,
                                  additional_required, _1, _2),
                      boost::bind(renderDataField, &actual_renderer_, _1, _2));
    // 2nd dummy name
    actual_renderer_.writeName(dummy_name2);
    // Finally, dump any RRSIGs in wire format.
    foreachRRSig(encoded_data_, rrsiglen_list,
                 boost::bind(renderDataField, &actual_renderer_, _1, _2));

    // Two sets of wire-format data should be identical.
    matchWireData(expected_renderer_.getData(), expected_renderer_.getLength(),
                  actual_renderer_.getData(), actual_renderer_.getLength());
}

void
RdataEncoderTest::addRdataCommon(const vector<ConstRdataPtr>& rrsigs) {
    // Basic check on the encoded data for (most of) all supported RR types,
    // in a comprehensive manner.
    for (size_t i = 0; test_rdata_list[i].rrclass != NULL; ++i) {
        SCOPED_TRACE(string(test_rdata_list[i].rrclass) + "/" +
                     test_rdata_list[i].rrtype);
        const RRClass rrclass(test_rdata_list[i].rrclass);
        const RRType rrtype(test_rdata_list[i].rrtype);
        const ConstRdataPtr rdata = createRdata(rrtype, rrclass,
                                                test_rdata_list[i].rdata);
        rdata_list_.clear();
        rdata_list_.push_back(rdata);
        checkEncode(rrclass, rrtype, rdata_list_,
                    test_rdata_list[i].n_varlen_fields, rrsigs);
    }
}

TEST_F(RdataEncoderTest, addRdata) {
    vector<ConstRdataPtr> rrsigs;
    addRdataCommon(rrsigs);     // basic tests without RRSIGs (empty vector)

    // Test with RRSIGs (covered type doesn't always match, but the encoder
    // doesn't check that)
    rrsigs.push_back(rrsig_rdata_);
    addRdataCommon(rrsigs);
}

void
RdataEncoderTest::addRdataMultiCommon(const vector<ConstRdataPtr>& rrsigs) {
    // Similar to addRdata(), but test with multiple RDATAs.
    // Four different cases are tested: a single fixed-len RDATA (A),
    // fixed-len data + domain name (MX), variable-len data only (TXT),
    // variable-len data + domain name (NAPTR).
    ConstRdataPtr a_rdata2 = createRdata(RRType::A(), RRClass::IN(),
                                         "192.0.2.54");
    rdata_list_.clear();
    rdata_list_.push_back(a_rdata_);
    rdata_list_.push_back(a_rdata2);
    checkEncode(RRClass::IN(), RRType::A(), rdata_list_, 0, rrsigs);

    ConstRdataPtr mx_rdata1 = createRdata(RRType::MX(), RRClass::IN(),
                                          "5 mx1.example.com");
    ConstRdataPtr mx_rdata2 = createRdata(RRType::MX(), RRClass::IN(),
                                          "10 mx2.example.com");
    rdata_list_.clear();
    rdata_list_.push_back(mx_rdata1);
    rdata_list_.push_back(mx_rdata2);
    checkEncode(RRClass::IN(), RRType::MX(), rdata_list_, 0, rrsigs);

    ConstRdataPtr txt_rdata1 = createRdata(RRType::TXT(), RRClass::IN(),
                                           "foo bar baz");
    ConstRdataPtr txt_rdata2 = createRdata(RRType::TXT(), RRClass::IN(),
                                          "another text data");
    rdata_list_.clear();
    rdata_list_.push_back(txt_rdata1);
    rdata_list_.push_back(txt_rdata2);
    checkEncode(RRClass::IN(), RRType::TXT(), rdata_list_, 1, rrsigs);

    ConstRdataPtr naptr_rdata1 =
        createRdata(RRType::NAPTR(), RRClass::IN(),
                    "100 50 \"s\" \"http\" \"\" _http._tcp.example.com");
    ConstRdataPtr naptr_rdata2 =
        createRdata(RRType::NAPTR(), RRClass::IN(),
                    "200 100 \"s\" \"http\" \"\" _http._tcp.example.com");
    rdata_list_.clear();
    rdata_list_.push_back(naptr_rdata1);
    rdata_list_.push_back(naptr_rdata2);
    checkEncode(RRClass::IN(), RRType::NAPTR(), rdata_list_, 1, rrsigs);
}

TEST_F(RdataEncoderTest, encodeLargeRdata) {
    // There should be no reason for a large RDATA to fail in encoding,
    // but we check such a  case explicitly.

    encoded_data_.resize(65535); // max unsigned 16-bit int
    isc::util::InputBuffer buffer(&encoded_data_[0], encoded_data_.size());
    const in::DHCID large_dhcid(buffer, encoded_data_.size());

    encoder_.start(RRClass::IN(), RRType::DHCID());
    encoder_.addRdata(large_dhcid);
    encoded_data_.resize(encoder_.getStorageLength());
    encoder_.encode(&encoded_data_[0], encoded_data_.size());

    // The encoded data should be identical to the original one.
    ASSERT_LT(sizeof(uint16_t), encoder_.getStorageLength());
    isc::util::InputBuffer ib(&encoded_data_[2], encoded_data_.size() - 2);
    const in::DHCID encoded_dhcid(ib, ib.getLength());
    EXPECT_EQ(0, encoded_dhcid.compare(large_dhcid));
}

TEST_F(RdataEncoderTest, addRdataMulti) {
    vector<ConstRdataPtr> rrsigs;
    addRdataMultiCommon(rrsigs); // test without RRSIGs (empty vector)

    // Tests with two RRSIGs
    rrsigs.push_back(rrsig_rdata_);
    rrsigs.push_back(createRdata(RRType::RRSIG(), RRClass::IN(),
                                 "A 5 2 3600 20120814220826 "
                                 "20120715220826 54321 com. FAKE"));
    addRdataMultiCommon(rrsigs);
}

TEST_F(RdataEncoderTest, badAddRdata) {
    // Some operations must follow start().
    EXPECT_THROW(encoder_.addRdata(*a_rdata_), isc::InvalidOperation);
    EXPECT_THROW(encoder_.getStorageLength(), isc::InvalidOperation);
    encoded_data_.resize(256); // allocate space of some arbitrary size
    EXPECT_THROW(encoder_.encode(&encoded_data_[0], encoded_data_.size()),
                 isc::InvalidOperation);

    // Bad buffer for encode
    encoder_.start(RRClass::IN(), RRType::A());
    encoder_.addRdata(*a_rdata_);
    const size_t buf_len = encoder_.getStorageLength();
    // NULL buffer for encode
    EXPECT_THROW(encoder_.encode(NULL, buf_len), isc::BadValue);
    // buffer length is too short
    encoded_data_.resize(buf_len - 1);
    EXPECT_THROW(encoder_.encode(&encoded_data_[0], buf_len - 1),
                 isc::BadValue);
    encoded_data_.resize(buf_len + 1);
    encoder_.encode(&encoded_data_[1], buf_len);

    // Type of RDATA and the specified RR type don't match.  addRdata() should
    // detect this inconsistency.
    encoder_.start(RRClass::IN(), RRType::AAAA());
    EXPECT_THROW(encoder_.addRdata(*a_rdata_), isc::BadValue);

    // Likewise.
    encoder_.start(RRClass::IN(), RRType::A());
    EXPECT_THROW(encoder_.addRdata(*aaaa_rdata_), isc::BadValue);

    // Likewise.  The encoder expects the first name completes the data, and
    // throws on the second due as an unexpected name field.
    const ConstRdataPtr rp_rdata =
        createRdata(RRType::RP(), RRClass::IN(), "a.example. b.example");
    encoder_.start(RRClass::IN(), RRType::NS());
    EXPECT_THROW(encoder_.addRdata(*rp_rdata), isc::BadValue);

    // Likewise.  The encoder considers the name data a variable length data
    // field, and throws on the first name.
    encoder_.start(RRClass::IN(), RRType::DHCID());
    EXPECT_THROW(encoder_.addRdata(*rp_rdata), isc::BadValue);

    // Likewise.  The text RDATA (2 bytes) will be treated as MX preference,
    // and the encoder will still expect to see a domain name.
    const ConstRdataPtr txt_rdata = createRdata(RRType::TXT(), RRClass::IN(),
                                                "a");
    encoder_.start(RRClass::IN(), RRType::MX());
    EXPECT_THROW(encoder_.addRdata(*txt_rdata), isc::BadValue);

    // Likewise.  Inconsistent name compression policy.
    const ConstRdataPtr ns_rdata =
        createRdata(RRType::NS(), RRClass::IN(), "ns.example");
    encoder_.start(RRClass::IN(), RRType::DNAME());
    EXPECT_THROW(encoder_.addRdata(*ns_rdata), isc::BadValue);

    // Same as the previous one, opposite inconsistency.
    const ConstRdataPtr dname_rdata =
        createRdata(RRType::DNAME(), RRClass::IN(), "dname.example");
    encoder_.start(RRClass::IN(), RRType::NS());
    EXPECT_THROW(encoder_.addRdata(*dname_rdata), isc::BadValue);

    // RDATA len exceeds the 16-bit range.  Technically not invalid, but
    // we don't support that (and it's practically useless anyway).
    encoded_data_.resize(65536); // use encoded_data_ for placeholder
    isc::util::InputBuffer buffer(&encoded_data_[0], encoded_data_.size());
    encoder_.start(RRClass::IN(), RRType::DHCID());
    EXPECT_THROW(encoder_.addRdata(in::DHCID(buffer, encoded_data_.size())),
                                   RdataEncodingError);

    // RRSIG cannot be used as the main RDATA type (can only be added as
    // a signature for some other type of RDATAs).
    EXPECT_THROW(encoder_.start(RRClass::IN(), RRType::RRSIG()),
                 isc::BadValue);
}

TEST_F(RdataEncoderTest, addSIGRdataOnly) {
    // Encoded data that only contain RRSIGs.  Mostly useless, but can happen
    // (in a partially broken zone) and it's accepted.
    encoder_.start(RRClass::IN(), RRType::A());
    encoder_.addSIGRdata(*rrsig_rdata_);
    encoded_data_.resize(encoder_.getStorageLength());
    encoder_.encode(&encoded_data_[0], encoded_data_.size());
    ASSERT_LT(sizeof(uint16_t), encoder_.getStorageLength());

    // The encoded data should be identical to the given one.
    isc::util::InputBuffer ib(&encoded_data_[2], encoded_data_.size() - 2);
    const generic::RRSIG encoded_sig(ib, ib.getLength());
    EXPECT_EQ(0, encoded_sig.compare(*rrsig_rdata_));
}

TEST_F(RdataEncoderTest, badAddSIGRdata) {
    // try adding SIG before start
    EXPECT_THROW(encoder_.addSIGRdata(*rrsig_rdata_), isc::InvalidOperation);

    // Very big RRSIG.  This implementation rejects it.
    isc::util::OutputBuffer ob(0);
    rrsig_rdata_->toWire(ob);
    // append dummy trailing signature to make it too big
    vector<uint8_t> dummy_sig(65536 - ob.getLength());
    ob.writeData(&dummy_sig[0], dummy_sig.size());
    ASSERT_EQ(65536, ob.getLength());

    isc::util::InputBuffer ib(ob.getData(), ob.getLength());
    const generic::RRSIG big_sigrdata(ib, ob.getLength());
    encoder_.start(RRClass::IN(), RRType::A());
    EXPECT_THROW(encoder_.addSIGRdata(big_sigrdata), RdataEncodingError);
}
}