/*
 *
 * (C) 2003-2020 Anope Team
 * Contact us at team@anope.org
 *
 * Please read COPYING and README for further details.
 *
 * Based on the original code of Epona by Lara.
 * Based on the original code of Services by Andy Church.
 */

#include "services.h"
#include "sockets.h"
#include "socketengine.h"
#include "logger.h"

#ifndef _WIN32
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#endif

std::map<int, Socket *> SocketEngine::Sockets;

uint32_t TotalRead = 0;
uint32_t TotalWritten = 0;

SocketIO NormalSocketIO;

sockaddrs::sockaddrs(const Anope::string &address)
{
	this->clear();
	if (!address.empty() && address.find_first_not_of_ci("0123456789abcdef.:") == Anope::string::npos)
		this->pton(address.find(':') != Anope::string::npos ? AF_INET6 : AF_INET, address);
}

void sockaddrs::clear()
{
	memset(this, 0, sizeof(*this));
}

int sockaddrs::family() const
{
	return sa.sa_family;
}

size_t sockaddrs::size() const
{
	switch (sa.sa_family)
	{
		case AF_INET:
			return sizeof(sa4);
		case AF_INET6:
			return sizeof(sa6);
		default:
			break;
	}

	return 0;
}

int sockaddrs::port() const
{
	switch (sa.sa_family)
	{
		case AF_INET:
			return ntohs(sa4.sin_port);
		case AF_INET6:
			return ntohs(sa6.sin6_port);
		default:
			break;
	}

	return -1;
}

Anope::string sockaddrs::addr() const
{
	char address[INET6_ADDRSTRLEN];

	switch (sa.sa_family)
	{
		case AF_INET:
			if (inet_ntop(AF_INET, &sa4.sin_addr, address, sizeof(address)))
				return address;
			break;
		case AF_INET6:
			if (inet_ntop(AF_INET6, &sa6.sin6_addr, address, sizeof(address)))
				return address;
			break;
		default:
			break;
	}

	return "";
}

Anope::string sockaddrs::reverse() const
{
	char address[128];

	switch (sa.sa_family)
	{
		case AF_INET6:
		{
			static const char hex[] = "0123456789abcdef";
			unsigned reverse_ip_count = 0;
			for (int j = 15; j >= 0; --j)
			{
				address[reverse_ip_count++] = hex[sa6.sin6_addr.s6_addr[j] & 0xF];
				address[reverse_ip_count++] = '.';
				address[reverse_ip_count++] = hex[sa6.sin6_addr.s6_addr[j] >> 4];
				address[reverse_ip_count++] = '.';
			}
			/* Remove the last '.' */
			address[reverse_ip_count - 1] = 0;
			return address;
		}
		case AF_INET:
		{
			unsigned long forward = sa4.sin_addr.s_addr;
			in_addr rev;
			rev.s_addr = forward << 24 | (forward & 0xFF00) << 8 | (forward & 0xFF0000) >> 8 | forward >> 24;
			if (inet_ntop(AF_INET, &rev, address, sizeof(address)))
				return address;
			break;
		}
	}

	return "";
}

bool sockaddrs::ipv6() const
{
	return sa.sa_family == AF_INET6;
}

bool sockaddrs::valid() const
{
	return size() != 0;
}

bool sockaddrs::operator==(const sockaddrs &other) const
{
	if (sa.sa_family != other.sa.sa_family)
		return false;
	switch (sa.sa_family)
	{
		case AF_INET:
			return (sa4.sin_port == other.sa4.sin_port) && (sa4.sin_addr.s_addr == other.sa4.sin_addr.s_addr);
		case AF_INET6:
			return (sa6.sin6_port == other.sa6.sin6_port) && !memcmp(sa6.sin6_addr.s6_addr, other.sa6.sin6_addr.s6_addr, 16);
		default:
			return !memcmp(this, &other, sizeof(*this));
	}

	return false;
}

void sockaddrs::pton(int type, const Anope::string &address, int pport)
{
	this->clear();

	switch (type)
	{
		case AF_INET:
		{
			int i = inet_pton(type, address.c_str(), &sa4.sin_addr);
			if (i <= 0)
				this->clear();
			else
			{
				sa4.sin_family = type;
				sa4.sin_port = htons(pport);
			}
			break;
		}
		case AF_INET6:
		{
			int i = inet_pton(type, address.c_str(), &sa6.sin6_addr);
			if (i <= 0)
				this->clear();
			else
			{
				sa6.sin6_family = type;
				sa6.sin6_port = htons(pport);
			}
			break;
		}
		default:
			break;
	}
}

void sockaddrs::ntop(int type, const void *src)
{
	char buf[INET6_ADDRSTRLEN];

	if (inet_ntop(type, src, buf, sizeof(buf)) != buf)
	{
		this->clear();
		return;
	}

	switch (type)
	{
		case AF_INET:
			sa4.sin_addr = *reinterpret_cast<const in_addr *>(src);
			sa4.sin_family = type;
			return;
		case AF_INET6:
			sa6.sin6_addr = *reinterpret_cast<const in6_addr *>(src);
			sa6.sin6_family = type;
			return;
		default:
			break;
	}

	this->clear();
}

cidr::cidr(const Anope::string &ip)
{
	bool ipv6 = ip.find(':') != Anope::string::npos;
	size_t sl = ip.find_last_of('/');

	if (sl == Anope::string::npos)
	{
		this->cidr_ip = ip;
		this->cidr_len = ipv6 ? 128 : 32;
		this->addr.pton(ipv6 ? AF_INET6 : AF_INET, ip);
	}
	else
	{
		Anope::string real_ip = ip.substr(0, sl);
		Anope::string cidr_range = ip.substr(sl + 1);

		this->cidr_ip = real_ip;
		this->cidr_len = ipv6 ? 128 : 32;
		try
		{
			if (cidr_range.is_pos_number_only())
				this->cidr_len = convertTo<unsigned int>(cidr_range);
		}
		catch (const ConvertException &) { }
		this->addr.pton(ipv6 ? AF_INET6 : AF_INET, real_ip);
	}
}

cidr::cidr(const Anope::string &ip, unsigned char len)
{
	bool ipv6 = ip.find(':') != Anope::string::npos;
	this->addr.pton(ipv6 ? AF_INET6 : AF_INET, ip);
	this->cidr_ip = ip;
	this->cidr_len = len;
}

cidr::cidr(const sockaddrs &a, unsigned char len) : addr(a)
{
	this->cidr_ip = a.addr();
	this->cidr_len = len;
}

Anope::string cidr::mask() const
{
	if ((this->addr.ipv6() && this->cidr_len == 128) || (!this->addr.ipv6() && this->cidr_len == 32))
		return this->cidr_ip;
	else
		return Anope::printf("%s/%d", this->cidr_ip.c_str(), this->cidr_len);
}

bool cidr::match(const sockaddrs &other)
{
	if (!valid() || !other.valid() || this->addr.sa.sa_family != other.sa.sa_family)
		return false;

	const uint8_t *ip, *their_ip;
	uint8_t byte, len = this->cidr_len;

	switch (this->addr.sa.sa_family)
	{
		case AF_INET:
			ip = reinterpret_cast<const uint8_t *>(&this->addr.sa4.sin_addr);
			if (len > 32)
				len = 32;
			byte = len / 8;
			their_ip = reinterpret_cast<const uint8_t *>(&other.sa4.sin_addr);
			break;
		case AF_INET6:
			ip = reinterpret_cast<const uint8_t *>(&this->addr.sa6.sin6_addr);
			if (len > 128)
				len = 128;
			byte = len / 8;
			their_ip = reinterpret_cast<const uint8_t *>(&other.sa6.sin6_addr);
			break;
		default:
			return false;
	}

	if (memcmp(ip, their_ip, byte))
		return false;

	ip += byte;
	their_ip += byte;

	byte = len % 8;
	if (byte)
	{
		uint8_t m = ~0 << (8 - byte);
		return (*ip & m) == (*their_ip & m);
	}

	return true;
}

bool cidr::operator<(const cidr &other) const
{
	if (this->addr.sa.sa_family != other.addr.sa.sa_family)
		return this->addr.sa.sa_family < other.addr.sa.sa_family;

	switch (this->addr.sa.sa_family)
	{
		case AF_INET:
		{
			unsigned int m = 0xFFFFFFFFU >> (32 - this->cidr_len);

			return (this->addr.sa4.sin_addr.s_addr & m) < (other.addr.sa4.sin_addr.s_addr & m);
		}
		case AF_INET6:
		{
			int i = memcmp(&this->addr.sa6.sin6_addr.s6_addr, &other.addr.sa6.sin6_addr.s6_addr, this->cidr_len / 8);
			if (i || this->cidr_len >= 128)
				return i < 0;

			// Now all thats left is to compare 'remainig' bits at offset this->cidr_len / 8
			int remaining = this->cidr_len % 8;
			unsigned char m = 0xFF << (8 - remaining);

			return (this->addr.sa6.sin6_addr.s6_addr[this->cidr_len / 8] & m) < (other.addr.sa6.sin6_addr.s6_addr[this->cidr_len / 8] & m);
		}
		default:
			throw CoreException("Unknown AFTYPE for cidr");
	}
}

bool cidr::operator==(const cidr &other) const
{
	return !(*this < other) && !(other < *this);
}

bool cidr::operator!=(const cidr &other) const
{
	return !(*this == other);
}

bool cidr::valid() const
{
	return this->addr.valid();
}

size_t cidr::hash::operator()(const cidr &s) const
{
	switch (s.addr.sa.sa_family)
	{
		case AF_INET:
		{
			unsigned int m = 0xFFFFFFFFU >> (32 - s.cidr_len);
			return s.addr.sa4.sin_addr.s_addr & m;
		}
		case AF_INET6:
		{
			size_t h = 0;

			for (unsigned i = 0; i < s.cidr_len / 8; ++i)
				h ^= (s.addr.sa6.sin6_addr.s6_addr[i] << ((i * 8) % sizeof(size_t)));

			int remaining = s.cidr_len % 8;
			unsigned char m = 0xFF << (8 - remaining);

			h ^= s.addr.sa6.sin6_addr.s6_addr[s.cidr_len / 8] & m;

			return h;
		}
		default:
			throw CoreException("Unknown AFTYPE for cidr");
	}
}

int SocketIO::Recv(Socket *s, char *buf, size_t sz)
{
	int i = recv(s->GetFD(), buf, sz, 0);
	if (i > 0)
		TotalRead += i;
	return i;
}

int SocketIO::Send(Socket *s, const char *buf, size_t sz)
{
	int i = send(s->GetFD(), buf, sz, 0);
	if (i > 0)
		TotalWritten += i;
	return i;
}

int SocketIO::Send(Socket *s, const Anope::string &buf)
{
	return this->Send(s, buf.c_str(), buf.length());
}

ClientSocket *SocketIO::Accept(ListenSocket *s)
{
	sockaddrs conaddr;

	socklen_t size = sizeof(conaddr);
	int newsock = accept(s->GetFD(), &conaddr.sa, &size);

	if (newsock >= 0)
	{
		ClientSocket *ns = s->OnAccept(newsock, conaddr);
		ns->flags[SF_ACCEPTED] = true;
		ns->OnAccept();
		return ns;
	}
	else
		throw SocketException("Unable to accept connection: " + Anope::LastError());
}

SocketFlag SocketIO::FinishAccept(ClientSocket *cs)
{
	return SF_ACCEPTED;
}

void SocketIO::Bind(Socket *s, const Anope::string &ip, int port)
{
	s->bindaddr.pton(s->IsIPv6() ? AF_INET6 : AF_INET, ip, port);
	if (bind(s->GetFD(), &s->bindaddr.sa, s->bindaddr.size()) == -1)
		throw SocketException("Unable to bind to address: " + Anope::LastError());
}

void SocketIO::Connect(ConnectionSocket *s, const Anope::string &target, int port)
{
	s->flags[SF_CONNECTING] = s->flags[SF_CONNECTED] = false;
	s->conaddr.pton(s->IsIPv6() ? AF_INET6 : AF_INET, target, port);
	int c = connect(s->GetFD(), &s->conaddr.sa, s->conaddr.size());
	if (c == -1)
	{
		if (!SocketEngine::IgnoreErrno())
			s->OnError(Anope::LastError());
		else
		{
			SocketEngine::Change(s, true, SF_WRITABLE);
			s->flags[SF_CONNECTING] = true;
		}
	}
	else
	{
		s->flags[SF_CONNECTED] = true;
		s->OnConnect();
	}
}

SocketFlag SocketIO::FinishConnect(ConnectionSocket *s)
{
	if (s->flags[SF_CONNECTED])
		return SF_CONNECTED;
	else if (!s->flags[SF_CONNECTING])
		throw SocketException("SocketIO::FinishConnect called for a socket not connected nor connecting?");

	int optval = 0;
	socklen_t optlen = sizeof(optval);
	if (!getsockopt(s->GetFD(), SOL_SOCKET, SO_ERROR, reinterpret_cast<char *>(&optval), &optlen) && !optval)
	{
		s->flags[SF_CONNECTED] = true;
		s->flags[SF_CONNECTING] = false;
		s->OnConnect();
		return SF_CONNECTED;
	}
	else
	{
		errno = optval;
		s->OnError(optval ? Anope::LastError() : "");
		return SF_DEAD;
	}
}

Socket::Socket()
{
	throw CoreException("Socket::Socket() ?");
}

Socket::Socket(int s, bool i, int type)
{
	this->io = &NormalSocketIO;
	this->ipv6 = i;
	if (s == -1)
		this->sock = socket(this->ipv6 ? AF_INET6 : AF_INET, type, 0);
	else
		this->sock = s;
	this->SetBlocking(false);
	SocketEngine::Sockets[this->sock] = this;
	SocketEngine::Change(this, true, SF_READABLE);
}

Socket::~Socket()
{
	SocketEngine::Change(this, false, SF_READABLE);
	SocketEngine::Change(this, false, SF_WRITABLE);
	anope_close(this->sock);
	this->io->Destroy();
	SocketEngine::Sockets.erase(this->sock);
}

int Socket::GetFD() const
{
	return sock;
}

bool Socket::IsIPv6() const
{
	return ipv6;
}

bool Socket::SetBlocking(bool state)
{
	int f = fcntl(this->GetFD(), F_GETFL, 0);
	if (state)
		return !fcntl(this->GetFD(), F_SETFL, f & ~O_NONBLOCK);
	else
		return !fcntl(this->GetFD(), F_SETFL, f | O_NONBLOCK);
}

void Socket::Bind(const Anope::string &ip, int port)
{
	this->io->Bind(this, ip, port);
}

bool Socket::Process()
{
	return true;
}

bool Socket::ProcessRead()
{
	return true;
}

bool Socket::ProcessWrite()
{
	return true;
}

void Socket::ProcessError()
{
}

ListenSocket::ListenSocket(const Anope::string &bindip, int port, bool i)
{
	this->SetBlocking(false);

	const int op = 1;
	setsockopt(this->GetFD(), SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<const char *>(&op), sizeof(op));

	this->bindaddr.pton(i ? AF_INET6 : AF_INET, bindip, port);
	this->io->Bind(this, bindip, port);

	if (listen(sock, SOMAXCONN) == -1)
		throw SocketException("Unable to listen: " + Anope::LastError());
}

ListenSocket::~ListenSocket()
{
}

bool ListenSocket::ProcessRead()
{
	try
	{
		this->io->Accept(this);
	}
	catch (const SocketException &ex)
	{
		Log() << ex.GetReason();
	}
	return true;
}

int SocketEngine::GetLastError()
{
#ifndef _WIN32
	return errno;
#else
	return WSAGetLastError();
#endif
}

void SocketEngine::SetLastError(int err)
{
#ifndef _WIN32
	errno = err;
#else
	WSASetLastError(err);
#endif
}

bool SocketEngine::IgnoreErrno()
{
	return GetLastError() == EAGAIN
		|| GetLastError() == EWOULDBLOCK
		|| GetLastError() == EINTR
		|| GetLastError() == EINPROGRESS;
}
