// Copyright (c) 2011-2014 The Bitcoin Core developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

//
// Unit tests for denial-of-service detection/prevention code
//



#include "keystore.h"
#include "main.h"
#include "net.h"
#include "pow.h"
#include "script.h"
#include "serialize.h"

#include <stdint.h>

#include <boost/assign/list_of.hpp> // for 'map_list_of()'
#include <boost/date_time/posix_time/posix_time_types.hpp>
#include <boost/foreach.hpp>
#include <boost/test/unit_test.hpp>

// Tests this internal-to-main.cpp method:
extern bool AddOrphanTx(const CTransaction& tx);
extern unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans);
extern std::map<uint256, CTransaction> mapOrphanTransactions;
extern std::map<uint256, std::set<uint256> > mapOrphanTransactionsByPrev;

CService ip(uint32_t i)
{
    struct in_addr s;
    s.s_addr = i;
    return CService(CNetAddr(s), Params().GetDefaultPort());
}

BOOST_AUTO_TEST_SUITE(DoS_tests)

BOOST_AUTO_TEST_CASE(DoS_banning)
{
    CNode::ClearBanned();
    CAddress addr1(ip(0xa0b0c001));
    CNode dummyNode1(INVALID_SOCKET, addr1, "", true);
    dummyNode1.nVersion = 1;
    Misbehaving(dummyNode1.GetId(), 100); // Should get banned
    SendMessages(&dummyNode1, false);
    BOOST_CHECK(CNode::IsBanned(addr1));
    BOOST_CHECK(!CNode::IsBanned(ip(0xa0b0c001|0x0000ff00))); // Different IP, not banned

    CAddress addr2(ip(0xa0b0c002));
    CNode dummyNode2(INVALID_SOCKET, addr2, "", true);
    dummyNode2.nVersion = 1;
    Misbehaving(dummyNode2.GetId(), 50);
    SendMessages(&dummyNode2, false);
    BOOST_CHECK(!CNode::IsBanned(addr2)); // 2 not banned yet...
    BOOST_CHECK(CNode::IsBanned(addr1));  // ... but 1 still should be
    Misbehaving(dummyNode2.GetId(), 50);
    SendMessages(&dummyNode2, false);
    BOOST_CHECK(CNode::IsBanned(addr2));
}

BOOST_AUTO_TEST_CASE(DoS_banscore)
{
    CNode::ClearBanned();
    mapArgs["-banscore"] = "111"; // because 11 is my favorite number
    CAddress addr1(ip(0xa0b0c001));
    CNode dummyNode1(INVALID_SOCKET, addr1, "", true);
    dummyNode1.nVersion = 1;
    Misbehaving(dummyNode1.GetId(), 100);
    SendMessages(&dummyNode1, false);
    BOOST_CHECK(!CNode::IsBanned(addr1));
    Misbehaving(dummyNode1.GetId(), 10);
    SendMessages(&dummyNode1, false);
    BOOST_CHECK(!CNode::IsBanned(addr1));
    Misbehaving(dummyNode1.GetId(), 1);
    SendMessages(&dummyNode1, false);
    BOOST_CHECK(CNode::IsBanned(addr1));
    mapArgs.erase("-banscore");
}

BOOST_AUTO_TEST_CASE(DoS_bantime)
{
    CNode::ClearBanned();
    int64_t nStartTime = GetTime();
    SetMockTime(nStartTime); // Overrides future calls to GetTime()

    CAddress addr(ip(0xa0b0c001));
    CNode dummyNode(INVALID_SOCKET, addr, "", true);
    dummyNode.nVersion = 1;

    Misbehaving(dummyNode.GetId(), 100);
    SendMessages(&dummyNode, false);
    BOOST_CHECK(CNode::IsBanned(addr));

    SetMockTime(nStartTime+60*60);
    BOOST_CHECK(CNode::IsBanned(addr));

    SetMockTime(nStartTime+60*60*24+1);
    BOOST_CHECK(!CNode::IsBanned(addr));
}

static bool CheckNBits(unsigned int nbits1, int64_t time1, unsigned int nbits2, int64_t time2)\
{
    if (time1 > time2)
        return CheckNBits(nbits2, time2, nbits1, time1);
    int64_t deltaTime = time2-time1;

    uint256 required;
    required.SetCompact(ComputeMinWork(nbits1, deltaTime));
    uint256 have;
    have.SetCompact(nbits2);
    return (have <= required);
}

BOOST_AUTO_TEST_CASE(DoS_checknbits)
{
    using namespace boost::assign; // for 'map_list_of()'

    // Timestamps,nBits from the bitcoin block chain.
    // These are the block-chain checkpoint blocks
    typedef std::map<int64_t, unsigned int> BlockData;
    BlockData chainData =
        map_list_of(1239852051,486604799)(1262749024,486594666)
        (1279305360,469854461)(1280200847,469830746)(1281678674,469809688)
        (1296207707,453179945)(1302624061,453036989)(1309640330,437004818)
        (1313172719,436789733);

    // Make sure CheckNBits considers every combination of block-chain-lock-in-points
    // "sane":
    BOOST_FOREACH(const BlockData::value_type& i, chainData)
    {
        BOOST_FOREACH(const BlockData::value_type& j, chainData)
        {
            BOOST_CHECK(CheckNBits(i.second, i.first, j.second, j.first));
        }
    }

    // Test a couple of insane combinations:
    BlockData::value_type firstcheck = *(chainData.begin());
    BlockData::value_type lastcheck = *(chainData.rbegin());

    // First checkpoint difficulty at or a while after the last checkpoint time should fail when
    // compared to last checkpoint
    BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*10, lastcheck.second, lastcheck.first));
    BOOST_CHECK(!CheckNBits(firstcheck.second, lastcheck.first+60*60*24*14, lastcheck.second, lastcheck.first));

    // ... but OK if enough time passed for difficulty to adjust downward:
    BOOST_CHECK(CheckNBits(firstcheck.second, lastcheck.first+60*60*24*365*4, lastcheck.second, lastcheck.first));
}

CTransaction RandomOrphan()
{
    std::map<uint256, CTransaction>::iterator it;
    it = mapOrphanTransactions.lower_bound(GetRandHash());
    if (it == mapOrphanTransactions.end())
        it = mapOrphanTransactions.begin();
    return it->second;
}

BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
{
    CKey key;
    key.MakeNewKey(true);
    CBasicKeyStore keystore;
    keystore.AddKey(key);

    // 50 orphan transactions:
    for (int i = 0; i < 50; i++)
    {
        CMutableTransaction tx;
        tx.vin.resize(1);
        tx.vin[0].prevout.n = 0;
        tx.vin[0].prevout.hash = GetRandHash();
        tx.vin[0].scriptSig << OP_1;
        tx.vout.resize(1);
        tx.vout[0].nValue = 1*CENT;
        tx.vout[0].scriptPubKey.SetDestination(key.GetPubKey().GetID());

        AddOrphanTx(tx);
    }

    // ... and 50 that depend on other orphans:
    for (int i = 0; i < 50; i++)
    {
        CTransaction txPrev = RandomOrphan();

        CMutableTransaction tx;
        tx.vin.resize(1);
        tx.vin[0].prevout.n = 0;
        tx.vin[0].prevout.hash = txPrev.GetHash();
        tx.vout.resize(1);
        tx.vout[0].nValue = 1*CENT;
        tx.vout[0].scriptPubKey.SetDestination(key.GetPubKey().GetID());
        SignSignature(keystore, txPrev, tx, 0);

        AddOrphanTx(tx);
    }

    // This really-big orphan should be ignored:
    for (int i = 0; i < 10; i++)
    {
        CTransaction txPrev = RandomOrphan();

        CMutableTransaction tx;
        tx.vout.resize(1);
        tx.vout[0].nValue = 1*CENT;
        tx.vout[0].scriptPubKey.SetDestination(key.GetPubKey().GetID());
        tx.vin.resize(500);
        for (unsigned int j = 0; j < tx.vin.size(); j++)
        {
            tx.vin[j].prevout.n = j;
            tx.vin[j].prevout.hash = txPrev.GetHash();
        }
        SignSignature(keystore, txPrev, tx, 0);
        // Re-use same signature for other inputs
        // (they don't have to be valid for this test)
        for (unsigned int j = 1; j < tx.vin.size(); j++)
            tx.vin[j].scriptSig = tx.vin[0].scriptSig;

        BOOST_CHECK(!AddOrphanTx(tx));
    }

    // Test LimitOrphanTxSize() function:
    LimitOrphanTxSize(40);
    BOOST_CHECK(mapOrphanTransactions.size() <= 40);
    LimitOrphanTxSize(10);
    BOOST_CHECK(mapOrphanTransactions.size() <= 10);
    LimitOrphanTxSize(0);
    BOOST_CHECK(mapOrphanTransactions.empty());
    BOOST_CHECK(mapOrphanTransactionsByPrev.empty());
}

BOOST_AUTO_TEST_SUITE_END()