// See the file "COPYING" in the main distribution directory for copyright.

#include "zeek/Hash.h"

#include "zeek/zeek-config.h"

#include <highwayhash/highwayhash_target.h>
#include <highwayhash/instruction_sets.h>
#include <highwayhash/sip_hash.h>

#include "zeek/DebugLogger.h"
#include "zeek/Desc.h"
#include "zeek/Reporter.h"
#include "zeek/Val.h" // needed for const.bif
#include "zeek/ZeekString.h"
#include "zeek/digest.h"

#include "const.bif.netvar_h"

namespace zeek::detail
	{

alignas(32) uint64_t KeyedHash::shared_highwayhash_key[4];
alignas(32) uint64_t KeyedHash::cluster_highwayhash_key[4];
alignas(16) unsigned long long KeyedHash::shared_siphash_key[2];

// we use the following lines to not pull in the highwayhash headers in Hash.h - but to check the
// types did not change underneath us.
static_assert(std::is_same<hash64_t, highwayhash::HHResult64>::value,
              "Highwayhash return values must match hash_x_t");
static_assert(std::is_same<hash128_t, highwayhash::HHResult128>::value,
              "Highwayhash return values must match hash_x_t");
static_assert(std::is_same<hash256_t, highwayhash::HHResult256>::value,
              "Highwayhash return values must match hash_x_t");

void KeyedHash::InitializeSeeds(const std::array<uint32_t, SEED_INIT_SIZE>& seed_data)
	{
	static_assert(std::is_same<decltype(KeyedHash::shared_siphash_key),
	                           highwayhash::SipHashState::Key>::value,
	              "Highwayhash Key is not unsigned long long[2]");
	static_assert(
		std::is_same<decltype(KeyedHash::shared_highwayhash_key), highwayhash::HHKey>::value,
		"Highwayhash HHKey is not uint64_t[4]");
	if ( seeds_initialized )
		return;

	// leaving this at being generated by md5, allowing user scripts that use hmac_md5 functionality
	// to get the same hash values as before. For now.
	internal_md5((const u_char*)seed_data.data(), sizeof(seed_data) - 16,
	             shared_hmac_md5_key); // The last 128 bits of buf are for siphash
	// yes, we use the same buffer twice to initialize two different keys. This should not really be
	// a security problem of any kind: hmac-md5 is not really used anymore - and even if it was, the
	// hashes should not reveal any information about their initialization vector.
	static_assert(sizeof(shared_highwayhash_key) == SHA256_DIGEST_LENGTH);
	calculate_digest(Hash_SHA256, (const u_char*)seed_data.data(), sizeof(seed_data) - 16,
	                 reinterpret_cast<unsigned char*>(shared_highwayhash_key));
	memcpy(shared_siphash_key, reinterpret_cast<const char*>(seed_data.data()) + 64, 16);

	seeds_initialized = true;
	}

void KeyedHash::InitOptions()
	{
	calculate_digest(Hash_SHA256, BifConst::digest_salt->Bytes(), BifConst::digest_salt->Len(),
	                 reinterpret_cast<unsigned char*>(cluster_highwayhash_key));
	}

hash64_t KeyedHash::Hash64(const void* bytes, uint64_t size)
	{
	return highwayhash::SipHash(shared_siphash_key, static_cast<const char*>(bytes), size);
	}

void KeyedHash::Hash128(const void* bytes, uint64_t size, hash128_t* result)
	{
	highwayhash::InstructionSets::Run<highwayhash::HighwayHash>(
		shared_highwayhash_key, static_cast<const char*>(bytes), size, result);
	}

void KeyedHash::Hash256(const void* bytes, uint64_t size, hash256_t* result)
	{
	highwayhash::InstructionSets::Run<highwayhash::HighwayHash>(
		shared_highwayhash_key, static_cast<const char*>(bytes), size, result);
	}

hash64_t KeyedHash::StaticHash64(const void* bytes, uint64_t size)
	{
	hash64_t result = 0;
	highwayhash::InstructionSets::Run<highwayhash::HighwayHash>(
		cluster_highwayhash_key, static_cast<const char*>(bytes), size, &result);
	return result;
	}

void KeyedHash::StaticHash128(const void* bytes, uint64_t size, hash128_t* result)
	{
	highwayhash::InstructionSets::Run<highwayhash::HighwayHash>(
		cluster_highwayhash_key, static_cast<const char*>(bytes), size, result);
	}

void KeyedHash::StaticHash256(const void* bytes, uint64_t size, hash256_t* result)
	{
	highwayhash::InstructionSets::Run<highwayhash::HighwayHash>(
		cluster_highwayhash_key, static_cast<const char*>(bytes), size, result);
	}

void init_hash_function()
	{
	// Make sure we have already called init_random_seed().
	if ( ! KeyedHash::IsInitialized() )
		reporter->InternalError("Zeek's hash functions aren't fully initialized");
	}

HashKey::HashKey(bool b)
	{
	Set(b);
	}

HashKey::HashKey(int i)
	{
	Set(i);
	}

HashKey::HashKey(zeek_int_t bi)
	{
	Set(bi);
	}

HashKey::HashKey(zeek_uint_t bu)
	{
	Set(bu);
	}

HashKey::HashKey(uint32_t u)
	{
	Set(u);
	}

HashKey::HashKey(const uint32_t u[], size_t n)
	{
	size = write_size = n * sizeof(u[0]);
	key = (char*)u;
	}

HashKey::HashKey(double d)
	{
	Set(d);
	}

HashKey::HashKey(const void* p)
	{
	Set(p);
	}

HashKey::HashKey(const char* s)
	{
	size = write_size = strlen(s); // note - skip final \0
	key = (char*)s;
	}

HashKey::HashKey(const String* s)
	{
	size = write_size = s->Len();
	key = (char*)s->Bytes();
	}

HashKey::HashKey(const void* bytes, size_t arg_size)
	{
	size = write_size = arg_size;
	key = CopyKey((char*)bytes, size);
	is_our_dynamic = true;
	}

HashKey::HashKey(const void* arg_key, size_t arg_size, hash_t arg_hash)
	{
	size = write_size = arg_size;
	hash = arg_hash;
	key = CopyKey((char*)arg_key, size);
	is_our_dynamic = true;
	}

HashKey::HashKey(const void* arg_key, size_t arg_size, hash_t arg_hash, bool /* dont_copy */)
	{
	size = write_size = arg_size;
	hash = arg_hash;
	key = (char*)arg_key;
	}

hash_t HashKey::Hash() const
	{
	if ( hash == 0 )
		hash = HashBytes(key, size);
#ifdef DEBUG
	ODesc d;
	Describe(&d);
	DBG_LOG(DBG_HASHKEY, "HashKey %p %s", this, d.Description());
#endif
	return hash;
	}

void* HashKey::TakeKey()
	{
	if ( is_our_dynamic )
		{
		is_our_dynamic = false;
		return key;
		}
	else
		return CopyKey(key, size);
	}

void HashKey::Describe(ODesc* d) const
	{
	char buf[64];
	snprintf(buf, 16, "%0" PRIx64, hash);
	d->Add(buf);
	d->SP();

	if ( size > 0 )
		{
		d->Add(IsAllocated() ? "(" : "[");

		for ( size_t i = 0; i < size; i++ )
			{
			if ( i > 0 )
				{
				d->SP();
				// Extra spacing every 8 bytes, for readability.
				if ( i % 8 == 0 )
					d->SP();
				}

			// Don't display unwritten content, only say how much there is.
			if ( i > write_size )
				{
				d->Add("<+");
				d->Add(static_cast<uint64_t>(size - write_size - 1));
				d->Add(" of ");
				d->Add(static_cast<uint64_t>(size));
				d->Add(" available>");
				break;
				}

			snprintf(buf, 3, "%02x", key[i]);
			d->Add(buf);
			}

		d->Add(IsAllocated() ? ")" : "]");
		}
	}

char* HashKey::CopyKey(const char* k, size_t s) const
	{
	char* k_copy = new char[s]; // s == 0 is okay, returns non-nil
	memcpy(k_copy, k, s);
	return k_copy;
	}

hash_t HashKey::HashBytes(const void* bytes, size_t size)
	{
	return KeyedHash::Hash64(bytes, size);
	}

void HashKey::Set(bool b)
	{
	key_u.b = b;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(b);
	}

void HashKey::Set(int i)
	{
	key_u.i = i;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(i);
	}

void HashKey::Set(zeek_int_t bi)
	{
	key_u.bi = bi;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(bi);
	}

void HashKey::Set(zeek_uint_t bu)
	{
	key_u.bi = zeek_int_t(bu);
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(bu);
	}

void HashKey::Set(uint32_t u)
	{
	key_u.u32 = u;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(u);
	}

void HashKey::Set(double d)
	{
	key_u.d = d;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(d);
	}

void HashKey::Set(const void* p)
	{
	key_u.p = p;
	key = reinterpret_cast<char*>(&key_u);
	size = write_size = sizeof(p);
	}

void HashKey::Reserve(const char* tag, size_t addl_size, size_t alignment)
	{
	ASSERT(! IsAllocated());
	size_t s0 = size;
	size_t s1 = util::memory_size_align(size, alignment);
	size = s1 + addl_size;

	DBG_LOG(DBG_HASHKEY, "HashKey %p reserving %lu/%lu: %lu -> %lu -> %lu [%s]", this, addl_size,
	        alignment, s0, s1, size, tag);
	}

void HashKey::Allocate()
	{
	if ( key != nullptr and key != reinterpret_cast<char*>(&key_u) )
		{
		reporter->InternalWarning("usage error in HashKey::Allocate(): already allocated");
		return;
		}

	is_our_dynamic = true;
	key = reinterpret_cast<char*>(new double[size / sizeof(double) + 1]);

	read_size = 0;
	write_size = 0;
	}

void HashKey::Write(const char* tag, bool b)
	{
	Write(tag, &b, sizeof(b), 0);
	}

void HashKey::Write(const char* tag, int i, bool align)
	{
	if ( ! IsAllocated() )
		{
		Set(i);
		return;
		}

	Write(tag, &i, sizeof(i), align ? sizeof(i) : 0);
	}

void HashKey::Write(const char* tag, zeek_int_t bi, bool align)
	{
	if ( ! IsAllocated() )
		{
		Set(bi);
		return;
		}

	Write(tag, &bi, sizeof(bi), align ? sizeof(bi) : 0);
	}

void HashKey::Write(const char* tag, zeek_uint_t bu, bool align)
	{
	if ( ! IsAllocated() )
		{
		Set(bu);
		return;
		}

	Write(tag, &bu, sizeof(bu), align ? sizeof(bu) : 0);
	}

void HashKey::Write(const char* tag, uint32_t u, bool align)
	{
	if ( ! IsAllocated() )
		{
		Set(u);
		return;
		}

	Write(tag, &u, sizeof(u), align ? sizeof(u) : 0);
	}

void HashKey::Write(const char* tag, double d, bool align)
	{
	if ( ! IsAllocated() )
		{
		Set(d);
		return;
		}

	Write(tag, &d, sizeof(d), align ? sizeof(d) : 0);
	}

void HashKey::Write(const char* tag, const void* bytes, size_t n, size_t alignment)
	{
	size_t s0 = write_size;
	AlignWrite(alignment);
	size_t s1 = write_size;
	EnsureWriteSpace(n);

	memcpy(key + write_size, bytes, n);
	write_size += n;

	DBG_LOG(DBG_HASHKEY, "HashKey %p writing %lu/%lu: %lu -> %lu -> %lu [%s]", this, n, alignment,
	        s0, s1, write_size, tag);
	}

void HashKey::SkipWrite(const char* tag, size_t n)
	{
	DBG_LOG(DBG_HASHKEY, "HashKey %p skip-writing %lu: %lu -> %lu [%s]", this, n, write_size,
	        write_size + n, tag);

	EnsureWriteSpace(n);
	write_size += n;
	}

void HashKey::AlignWrite(size_t alignment)
	{
	ASSERT(IsAllocated());

	if ( alignment == 0 )
		return;

	size_t old_size = write_size;

	write_size = util::memory_size_align(write_size, alignment);

	if ( write_size > size )
		reporter->InternalError("buffer overflow in HashKey::AlignWrite(): "
		                        "after alignment, %lu bytes used of %lu allocated",
		                        write_size, size);

	while ( old_size < write_size )
		key[old_size++] = '\0';
	}

void HashKey::AlignRead(size_t alignment) const
	{
	ASSERT(IsAllocated());

	if ( alignment == 0 )
		return;

	int old_size = read_size;

	read_size = util::memory_size_align(read_size, alignment);

	if ( read_size > size )
		reporter->InternalError("buffer overflow in HashKey::AlignRead(): "
		                        "after alignment, %lu bytes used of %lu allocated",
		                        read_size, size);
	}

void HashKey::Read(const char* tag, bool& b) const
	{
	Read(tag, &b, sizeof(b), 0);
	}

void HashKey::Read(const char* tag, int& i, bool align) const
	{
	Read(tag, &i, sizeof(i), align ? sizeof(i) : 0);
	}

void HashKey::Read(const char* tag, zeek_int_t& i, bool align) const
	{
	Read(tag, &i, sizeof(i), align ? sizeof(i) : 0);
	}

void HashKey::Read(const char* tag, zeek_uint_t& u, bool align) const
	{
	Read(tag, &u, sizeof(u), align ? sizeof(u) : 0);
	}

void HashKey::Read(const char* tag, uint32_t& u, bool align) const
	{
	Read(tag, &u, sizeof(u), align ? sizeof(u) : 0);
	}

void HashKey::Read(const char* tag, double& d, bool align) const
	{
	Read(tag, &d, sizeof(d), align ? sizeof(d) : 0);
	}

void HashKey::Read(const char* tag, void* out, size_t n, size_t alignment) const
	{
	size_t s0 = read_size;
	AlignRead(alignment);
	size_t s1 = read_size;
	EnsureReadSpace(n);

	// In case out is nil, make sure nothing is to be read, and only memcpy
	// when there is a non-zero amount. Memory checkers don't nullpointers
	// in memcpy even if the size is 0.
	ASSERT(out != nullptr || (out == nullptr && n == 0));

	if ( n > 0 )
		{
		memcpy(out, key + read_size, n);
		read_size += n;
		}

	DBG_LOG(DBG_HASHKEY, "HashKey %p reading %lu/%lu: %lu -> %lu -> %lu [%s]", this, n, alignment,
	        s0, s1, read_size, tag);
	}

void HashKey::SkipRead(const char* tag, size_t n) const
	{
	DBG_LOG(DBG_HASHKEY, "HashKey %p skip-reading %lu: %lu -> %lu [%s]", this, n, read_size,
	        read_size + n, tag);

	EnsureReadSpace(n);
	read_size += n;
	}

void HashKey::EnsureWriteSpace(size_t n) const
	{
	if ( n == 0 )
		return;

	if ( ! IsAllocated() )
		reporter->InternalError("usage error in HashKey::EnsureWriteSpace(): "
		                        "size-checking unreserved buffer");
	if ( write_size + n > size )
		reporter->InternalError("buffer overflow in HashKey::Write(): writing %lu "
		                        "bytes with %lu remaining",
		                        n, size - write_size);
	}

void HashKey::EnsureReadSpace(size_t n) const
	{
	if ( n == 0 )
		return;

	if ( ! IsAllocated() )
		reporter->InternalError("usage error in HashKey::EnsureReadSpace(): "
		                        "size-checking unreserved buffer");
	if ( read_size + n > size )
		reporter->InternalError("buffer overflow in HashKey::EnsureReadSpace(): reading %lu "
		                        "bytes with %lu remaining",
		                        n, size - read_size);
	}

	} // namespace zeek::detail