eqemu-server/common/net/servertalk_client_connection.cpp

/*	EQEmu: EQEmulator

	Copyright (C) 2001-2026 EQEmu Development Team

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "servertalk_client_connection.h"

#include "common/eqemu_logsys.h"
#include "common/net/dns.h"

EQ::Net::ServertalkClient::ServertalkClient(const std::string &addr, int port, bool ipv6, const std::string &identifier, const std::string &credentials)
	: m_timer(std::make_unique<EQ::Timer>(100, true, std::bind(&EQ::Net::ServertalkClient::Connect, this)))
{
	m_port = port;
	m_ipv6 = ipv6;
	m_identifier = identifier.empty() ? "Unknown" : identifier;
	m_credentials = credentials;
	m_connecting = false;
	DNSLookup(addr, port, false, [this](const std::string &address) {
		m_addr = address;
	});
}

EQ::Net::ServertalkClient::~ServertalkClient()
{
}

void EQ::Net::ServertalkClient::Send(uint16_t opcode, EQ::Net::Packet &p)
{
	// pad zero size packets
	if (p.Length() == 0) {
		p.PutUInt8(0, 0);
	}

	EQ::Net::DynamicPacket out;
	out.PutUInt32(0, p.Length());
	out.PutUInt16(4, opcode);
	out.PutPacket(6, p);

	InternalSend(ServertalkMessage, out);
}

void EQ::Net::ServertalkClient::SendPacket(ServerPacket *p)
{
	EQ::Net::DynamicPacket pout;
	if (p->pBuffer) {
		pout.PutData(0, p->pBuffer, p->size);
	}
	Send(p->opcode, pout);
}

void EQ::Net::ServertalkClient::OnMessage(uint16_t opcode, std::function<void(uint16_t, EQ::Net::Packet&)> cb)
{
	m_message_callbacks.emplace(std::make_pair(opcode, cb));
}

void EQ::Net::ServertalkClient::OnMessage(std::function<void(uint16_t, EQ::Net::Packet&)> cb)
{
	m_message_callback = cb;
}

void EQ::Net::ServertalkClient::Connect()
{
	if (m_addr.length() == 0 || m_port == 0 || m_connection || m_connecting) {
		return;
	}

	m_connecting = true;
	EQ::Net::TCPConnection::Connect(m_addr, m_port, false, [this](std::shared_ptr<EQ::Net::TCPConnection> connection) {
		if (connection == nullptr) {
			LogNetTCP("Error connecting to {0}:{1}, attempting to reconnect...", m_addr, m_port);
			m_connecting = false;
			return;
		}

		LogNetTCP("Connected to {0}:{1}", m_addr, m_port);
		m_connection = connection;
		m_connection->OnDisconnect([this](EQ::Net::TCPConnection *c) {
			LogNetTCP("Connection lost to {0}:{1}, attempting to reconnect...", m_addr, m_port);
			m_connection.reset();
		});

		m_connection->OnRead(std::bind(&EQ::Net::ServertalkClient::ProcessData, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));
		m_connection->Start();

		SendHandshake();

		if (m_on_connect_cb) {
			m_on_connect_cb(this);
		}

		m_connecting = false;
	});
}

void EQ::Net::ServertalkClient::ProcessData(EQ::Net::TCPConnection *c, const unsigned char *data, size_t length)
{
	m_buffer.insert(m_buffer.end(), (const char*)data, (const char*)data + length);
	ProcessReadBuffer();
}

void EQ::Net::ServertalkClient::SendHello()
{
	EQ::Net::DynamicPacket p;
	InternalSend(ServertalkClientHello, p);
}

void EQ::Net::ServertalkClient::InternalSend(ServertalkPacketType type, EQ::Net::Packet &p)
{
	if (!m_connection)
		return;

	EQ::Net::DynamicPacket out;
	out.PutUInt32(0, (uint32_t)p.Length());
	out.PutUInt8(4, (uint8_t)type);
	if (p.Length() > 0) {
		out.PutPacket(5, p);
	}

	m_connection->Write((const char*)out.Data(), out.Length());
}

void EQ::Net::ServertalkClient::ProcessReadBuffer()
{
	size_t current = 0;
	size_t total = m_buffer.size();

	while (current < total) {
		auto left = total - current;

		/*
		//header:
		//uint32 length;
		//uint8 type;
		*/
		size_t length = 0;
		uint8_t type = 0;
		if (left < 5) {
			break;
		}

		length = *(uint32_t*)&m_buffer[current];
		type = *(uint8_t*)&m_buffer[current + 4];

		if (current + 5 + length > total) {
			break;
		}

		if (length == 0) {
			EQ::Net::DynamicPacket p;
			switch (type) {
			case ServertalkServerHello:
				ProcessHello(p);
				break;
			case ServertalkMessage:
				ProcessMessage(p);
				break;
			}
		}
		else {
			EQ::Net::StaticPacket p(&m_buffer[current + 5], length);
			switch (type) {
			case ServertalkServerHello:
				ProcessHello(p);
				break;
			case ServertalkMessage:
				ProcessMessage(p);
				break;
			}
		}

		current += length + 5;
	}

	if (current == total) {
		m_buffer.clear();
	}
	else {
		m_buffer.erase(m_buffer.begin(), m_buffer.begin() + current);
	}
}

void EQ::Net::ServertalkClient::ProcessHello(EQ::Net::Packet &p)
{
	try {
		SendHandshake();

		if (m_on_connect_cb) {
			m_on_connect_cb(this);
		}
}
	catch (std::exception &ex) {
		LogError("Error parsing hello from server: {0}", ex.what());
		m_connection->Disconnect();

		if (m_on_connect_cb) {
			m_on_connect_cb(nullptr);
		}
	}
}

void EQ::Net::ServertalkClient::ProcessMessage(EQ::Net::Packet &p)
{
	try {
		auto length = p.GetUInt32(0);
		auto opcode = p.GetUInt16(4);
		if (length > 0) {
			auto data = p.GetString(6, length);

			size_t message_len = length;
			EQ::Net::StaticPacket packet(&data[0], message_len);

			auto cb = m_message_callbacks.find(opcode);
			if (cb != m_message_callbacks.end()) {
				cb->second(opcode, packet);
			}

			if (m_message_callback) {
				m_message_callback(opcode, packet);
			}
		}
	}
	catch (std::exception &ex) {
		LogError("Error parsing message from server: {0}", ex.what());
	}
}

void EQ::Net::ServertalkClient::SendHandshake()
{
	EQ::Net::DynamicPacket handshake;
	handshake.PutString(0, m_identifier);
	handshake.PutString(m_identifier.length() + 1, m_credentials);
	handshake.PutUInt8(m_identifier.length() + 1 + m_credentials.length(), 0);
	InternalSend(ServertalkClientDowngradeSecurityHandshake, handshake);
}