Martin Michelsen
1542 lines
56 KiB
C++
1542 lines
56 KiB
C++
#include "IPStackSimulator.hh"
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#include <stdint.h>
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#include <string.h>
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#include <phosg/Network.hh>
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#include <phosg/Random.hh>
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#include <phosg/Time.hh>
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#include <string>
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#include "DNSServer.hh"
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#include "GameServer.hh"
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#include "IPFrameInfo.hh"
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#include "Loggers.hh"
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using namespace std;
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static size_t unescape_hdlc_frame_inplace(void* vdata, size_t size) {
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uint8_t* data = reinterpret_cast<uint8_t*>(vdata);
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if (size < 2) {
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throw runtime_error("escaped HDLC frame is too small");
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}
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if (data[0] != 0x7E) {
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throw runtime_error("HDLC frame does not begin with 7E");
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}
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if (data[size - 1] != 0x7E) {
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throw runtime_error("HDLC frame does not end with 7E");
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}
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size_t read_offset = 1;
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size_t write_offset = 1;
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while (read_offset < size - 1) {
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uint8_t ch = data[read_offset++];
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if (ch == 0x7D) {
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if (read_offset >= size - 1) {
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throw runtime_error("abort sequence received");
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}
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ch = data[read_offset++] ^ 0x20;
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}
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data[write_offset++] = ch;
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}
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if (write_offset > size - 1) {
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throw logic_error("unescaping HDLC frame resulted in longer data string");
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}
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data[write_offset++] = 0x7E;
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return write_offset;
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}
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static string escape_hdlc_frame(const void* data, size_t size, uint32_t escape_control_character_flags = 0xFFFFFFFF) {
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if (size < 2) {
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throw runtime_error("HDLC frame too small for start and end sentinels");
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}
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phosg::StringReader r(data, size);
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if (r.pget_u8(size - 1) != 0x7E) {
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throw runtime_error("HDLC frame does not end with 7E");
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}
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r.truncate(size - 1);
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if (r.get_u8() != 0x7E) {
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throw runtime_error("HDLC frame does not begin with 7E");
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}
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string ret("\x7E", 1);
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while (!r.eof()) {
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uint8_t ch = r.get_u8();
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if ((ch == 0x7D) || (ch == 0x7E) || ((ch < 0x20) && ((escape_control_character_flags >> ch) & 1))) {
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ret.push_back(0x7D);
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ret.push_back(ch ^ 0x20);
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} else {
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ret.push_back(ch);
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}
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}
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ret.push_back(0x7E);
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return ret;
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}
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static string escape_hdlc_frame(const string& data, uint32_t escape_control_character_flags = 0xFFFFFFFF) {
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return escape_hdlc_frame(data.data(), data.size(), escape_control_character_flags);
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}
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// Note: these functions exist because seq nums are allowed to wrap around the
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// 32-bit integer space by design. We have to do the subtraction before the
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// comparison to allow integer overflow to occur if needed.
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static inline bool seq_num_less(uint32_t a, uint32_t b) {
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return (a - b) & 0x80000000;
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}
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static inline bool seq_num_less_or_equal(uint32_t a, uint32_t b) {
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return (a == b) || seq_num_less(a, b);
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}
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static inline bool seq_num_greater(uint32_t a, uint32_t b) {
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return (b - a) & 0x80000000;
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}
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static __attribute__((unused)) inline bool seq_num_greater_or_equal(uint32_t a, uint32_t b) {
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return (a == b) || seq_num_greater(a, b);
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}
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IPSSClient::TCPConnection::TCPConnection(std::shared_ptr<IPSSClient> client)
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: client(client),
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resend_push_timer(*client->io_context) {}
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void IPSSClient::TCPConnection::drain_outbound_data(size_t size) {
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this->outbound_data_bytes -= size;
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while (size > 0 && !this->outbound_data.empty()) {
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auto& front_block = this->outbound_data.front();
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if (front_block.size() <= size) {
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size -= front_block.size();
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this->outbound_data.pop_front();
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} else {
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front_block = front_block.substr(size);
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size = 0;
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}
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}
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if (size > 0) {
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throw logic_error("attempted to drain more outbound data than was present");
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}
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}
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void IPSSClient::TCPConnection::linearize_outbound_data(size_t size) {
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while (this->outbound_data.size() > 1 && this->outbound_data.front().size() < size) {
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auto second_block_it = this->outbound_data.begin();
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second_block_it++;
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this->outbound_data.front() += *second_block_it;
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this->outbound_data.erase(second_block_it);
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}
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}
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IPSSClient::IPSSClient(
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shared_ptr<IPStackSimulator> sim,
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uint64_t network_id,
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VirtualNetworkProtocol protocol,
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asio::ip::tcp::socket&& sock)
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: io_context(sim->get_io_context()),
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sim(sim),
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network_id(network_id),
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sock(std::move(sock)),
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protocol(protocol),
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mac_addr(0),
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ipv4_addr(0),
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idle_timeout_timer(*sim->get_io_context()) {
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this->reschedule_idle_timeout();
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}
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void IPSSClient::reschedule_idle_timeout() {
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auto sim = this->sim.lock();
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if (!sim) {
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throw runtime_error("cannot reschedule idle timeout when simulator is missing");
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}
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this->idle_timeout_timer.cancel();
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this->idle_timeout_timer.expires_after(std::chrono::microseconds(sim->get_state()->client_idle_timeout_usecs));
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this->idle_timeout_timer.async_wait([this, sim](std::error_code ec) {
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if (!ec) {
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sim->log.info_f("Idle timeout expired on N-{:X}", this->network_id);
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this->sock.close();
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}
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});
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}
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IPSSChannel::IPSSChannel(
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std::shared_ptr<IPStackSimulator> sim,
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std::weak_ptr<IPSSClient> ipss_client,
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std::weak_ptr<IPSSClient::TCPConnection> tcp_conn,
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Version version,
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uint8_t language,
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const std::string& name,
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phosg::TerminalFormat terminal_send_color,
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phosg::TerminalFormat terminal_recv_color)
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: Channel(version, language, name, terminal_send_color, terminal_recv_color),
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sim(sim),
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ipss_client(ipss_client),
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tcp_conn(tcp_conn),
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data_available_signal(sim->io_context->get_executor()) {}
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std::string IPSSChannel::default_name() const {
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auto ipc = this->ipss_client.lock();
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if (ipc) {
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string addr_str = str_for_endpoint(ipc->sock.remote_endpoint());
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return std::format("ipss:N-{}:{}", ipc->network_id, addr_str);
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} else {
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return std::format("ipss:N-{}:__unknown_address__", ipc->network_id);
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}
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}
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bool IPSSChannel::connected() const {
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auto ipss_client = this->ipss_client.lock();
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auto tcp_conn = this->tcp_conn.lock();
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return tcp_conn && ipss_client && ipss_client->sock.is_open();
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}
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void IPSSChannel::disconnect() {
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auto c = this->ipss_client.lock();
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auto conn = this->tcp_conn.lock();
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if (c && conn) {
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sim->schedule_send_pending_push_frame(conn, 0);
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this->tcp_conn.reset();
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this->ipss_client.reset();
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this->data_available_signal.set();
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}
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}
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void IPSSChannel::add_inbound_data(const void* data, size_t size) {
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// If recv_buf is not null, there is a coroutine waiting to receive data, and
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// inbound_data must be empty. Copy the data directly to the waiting
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// coroutine's buffer, and put the rest in this->inbound_data if needed.
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if (this->recv_buf) {
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size_t direct_size = min<size_t>(this->recv_buf_size, size);
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memcpy(this->recv_buf, data, direct_size);
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data = reinterpret_cast<const uint8_t*>(data) + direct_size;
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size -= direct_size;
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this->recv_buf_size -= direct_size;
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this->recv_buf = this->recv_buf_size
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? reinterpret_cast<uint8_t*>(this->recv_buf) + direct_size
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: nullptr;
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}
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// If there is still data left after the above, add it to the pending inbound
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// data buffer
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if (size > 0) {
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this->inbound_data.emplace_back(reinterpret_cast<const char*>(data), size);
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}
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// Notify the waiting coroutine (if any) that data is available
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this->data_available_signal.set();
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}
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void IPSSChannel::send_raw(string&& data) {
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auto c = this->ipss_client.lock();
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if (!c) {
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return;
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}
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auto conn = this->tcp_conn.lock();
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if (!conn) {
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return;
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}
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auto sim = c->sim.lock();
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if (!sim) {
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return;
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}
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conn->outbound_data_bytes += data.size();
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conn->outbound_data.emplace_back(std::move(data));
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// If we're already waiting for an ACK from the remote client, don't send
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// another PSH right now - we will either send another PSH when we receive
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// the ACK or will retry sending the PSH soon (which will then include the
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// new data, if it's within the MTU from the last acked sequence number).
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if (!conn->awaiting_ack) {
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sim->schedule_send_pending_push_frame(conn, 0);
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}
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c->reschedule_idle_timeout();
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}
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asio::awaitable<void> IPSSChannel::recv_raw(void* data, size_t size) {
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if (this->recv_buf) {
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throw logic_error("recv_raw called again when it was already pending");
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}
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// Receive as much data as possible from the pending inbound data buffer
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while (size && !this->inbound_data.empty()) {
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auto& front_buf = this->inbound_data.front();
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if (size >= front_buf.size()) {
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memcpy(data, front_buf.data(), front_buf.size());
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data = reinterpret_cast<uint8_t*>(data) + front_buf.size();
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size -= front_buf.size();
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this->inbound_data.pop_front();
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} else {
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memcpy(data, front_buf.data(), size);
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data = reinterpret_cast<uint8_t*>(data) + size;
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front_buf = front_buf.substr(size);
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size = 0;
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}
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}
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// If there's still more data to read, block until it's available
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// (add_inbound_data is responsible for waking this coroutine)
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if (size > 0) {
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this->recv_buf = data;
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this->recv_buf_size = size;
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while (this->recv_buf) {
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if (!this->connected()) {
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throw runtime_error("IPSS channel closed");
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}
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this->data_available_signal.clear();
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co_await this->data_available_signal.wait();
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}
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}
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}
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IPStackSimulator::IPStackSimulator(shared_ptr<ServerState> state)
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: Server(state->io_context, "[IPStackSimulator] "), state(state) {
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this->host_mac_address_bytes.clear(0x90);
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this->broadcast_mac_address_bytes.clear(0xFF);
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}
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void IPStackSimulator::listen(const std::string& name, const string& addr, int port, VirtualNetworkProtocol protocol) {
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if (port == 0) {
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throw std::runtime_error("Listening port cannot be zero");
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}
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asio::ip::address asio_addr = addr.empty() ? asio::ip::address_v4::any() : asio::ip::make_address(addr);
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auto sock = make_shared<IPSSSocket>();
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sock->name = name;
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sock->endpoint = asio::ip::tcp::endpoint(asio_addr, port);
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sock->protocol = protocol;
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this->add_socket(std::move(sock));
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}
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uint32_t IPStackSimulator::connect_address_for_remote_address(uint32_t remote_addr) {
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// Use an address not on the same subnet as the client, so that PSO Plus and
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// Episode III will think they're talking to a remote network and won't
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// reject the connection.
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return ((remote_addr & 0xFF000000) == 0x23000000) ? 0x24242424 : 0x23232323;
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}
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uint64_t IPStackSimulator::tcp_conn_key_for_connection(std::shared_ptr<const IPSSClient::TCPConnection> conn) {
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return (static_cast<uint64_t>(conn->server_addr) << 32) |
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(static_cast<uint64_t>(conn->server_port) << 16) |
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static_cast<uint64_t>(conn->client_port);
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}
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uint64_t IPStackSimulator::tcp_conn_key_for_client_frame(const IPv4Header& ipv4, const TCPHeader& tcp) {
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return (static_cast<uint64_t>(ipv4.dest_addr) << 32) |
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(static_cast<uint64_t>(tcp.dest_port) << 16) |
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static_cast<uint64_t>(tcp.src_port);
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}
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uint64_t IPStackSimulator::tcp_conn_key_for_client_frame(const FrameInfo& fi) {
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if (!fi.ipv4 || !fi.tcp) {
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throw logic_error("tcp_conn_key_for_frame called on non-TCP frame");
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}
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return IPStackSimulator::tcp_conn_key_for_client_frame(*fi.ipv4, *fi.tcp);
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}
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string IPStackSimulator::str_for_ipv4_netloc(uint32_t addr, uint16_t port) {
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be_uint32_t be_addr = addr;
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char addr_str[INET_ADDRSTRLEN];
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if (!inet_ntop(AF_INET, &be_addr, addr_str, INET_ADDRSTRLEN)) {
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return std::format("<UNKNOWN>:{}", port);
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} else {
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return std::format("{}:{}", addr_str, port);
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}
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}
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string IPStackSimulator::str_for_tcp_connection(
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shared_ptr<const IPSSClient> c, std::shared_ptr<const IPSSClient::TCPConnection> conn) {
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uint64_t key = IPStackSimulator::tcp_conn_key_for_connection(conn);
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string server_netloc_str = str_for_ipv4_netloc(conn->server_addr, conn->server_port);
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string client_netloc_str = str_for_ipv4_netloc(c->ipv4_addr, conn->client_port);
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return std::format("{:016X} ({} -> {})", key, client_netloc_str, server_netloc_str);
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}
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asio::awaitable<void> IPStackSimulator::send_ethernet_tapserver_frame(
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shared_ptr<IPSSClient> c, FrameInfo::Protocol proto, const void* data, size_t size) const {
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struct {
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phosg::le_uint16_t frame_size;
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EthernetHeader ether;
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} header;
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static_assert(sizeof(header) == 0x10, "Ethernet tapserver header size is incorrect");
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header.ether.dest_mac = c->mac_addr;
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header.ether.src_mac = this->host_mac_address_bytes;
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switch (proto) {
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case FrameInfo::Protocol::NONE:
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throw logic_error("layer 3 protocol not specified");
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case FrameInfo::Protocol::LCP:
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throw logic_error("cannot send LCP frame over Ethernet");
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case FrameInfo::Protocol::IPV4:
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header.ether.protocol = 0x0800;
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break;
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case FrameInfo::Protocol::ARP:
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header.ether.protocol = 0x0806;
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break;
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default:
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throw logic_error("unknown layer 3 protocol");
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}
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header.frame_size = size + sizeof(EthernetHeader);
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array<asio::const_buffer, 2> bufs{
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asio::buffer(static_cast<const void*>(&header), sizeof(header)),
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asio::buffer(data, size)};
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co_await asio::async_write(c->sock, bufs, asio::use_awaitable);
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}
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asio::awaitable<void> IPStackSimulator::send_hdlc_frame(
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shared_ptr<IPSSClient> c, FrameInfo::Protocol proto, const void* data, size_t size, bool is_raw) const {
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HDLCHeader hdlc;
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hdlc.start_sentinel1 = 0x7E;
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hdlc.address = 0xFF;
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hdlc.control = 0x03;
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switch (proto) {
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case FrameInfo::Protocol::NONE:
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throw logic_error("layer 3 protocol not specified");
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case FrameInfo::Protocol::LCP:
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hdlc.protocol = 0xC021;
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break;
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case FrameInfo::Protocol::PAP:
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hdlc.protocol = 0xC023;
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break;
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case FrameInfo::Protocol::IPCP:
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hdlc.protocol = 0x8021;
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break;
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case FrameInfo::Protocol::IPV4:
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hdlc.protocol = 0x0021;
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break;
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case FrameInfo::Protocol::ARP:
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throw runtime_error("cannot send ARP packets over HDLC");
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default:
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throw logic_error("unknown layer 3 protocol");
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}
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phosg::StringWriter w;
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w.put(hdlc);
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w.write(data, size);
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w.put_u16l(FrameInfo::computed_hdlc_checksum(w.str().data() + 1, w.size() - 1));
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w.put_u8(0x7E);
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string escaped = escape_hdlc_frame(w.str(), c->hdlc_escape_control_character_flags);
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if (this->log.debug_f("Sending HDLC frame to virtual network (escaped to {:X} bytes)", escaped.size())) {
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phosg::print_data(stderr, w.str());
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}
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if (!is_raw) {
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phosg::le_uint16_t frame_size = escaped.size();
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array<asio::const_buffer, 2> bufs{
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asio::buffer(static_cast<const void*>(&frame_size), sizeof(frame_size)),
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asio::buffer(escaped.data(), escaped.size())};
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co_await asio::async_write(c->sock, bufs, asio::use_awaitable);
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} else {
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co_await asio::async_write(c->sock, asio::buffer(escaped.data(), escaped.size()), asio::use_awaitable);
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}
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}
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asio::awaitable<void> IPStackSimulator::send_layer3_frame(
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shared_ptr<IPSSClient> c, FrameInfo::Protocol proto, const void* data, size_t size) const {
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switch (c->protocol) {
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case VirtualNetworkProtocol::ETHERNET_TAPSERVER:
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co_await this->send_ethernet_tapserver_frame(c, proto, data, size);
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break;
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case VirtualNetworkProtocol::HDLC_TAPSERVER:
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co_await this->send_hdlc_frame(c, proto, data, size, false);
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break;
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case VirtualNetworkProtocol::HDLC_RAW:
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co_await this->send_hdlc_frame(c, proto, data, size, true);
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break;
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default:
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throw logic_error("unknown link type");
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}
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}
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|
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asio::awaitable<void> IPStackSimulator::on_client_frame(shared_ptr<IPSSClient> c, const void* data, size_t size) {
|
|
FrameInfo::LinkType link_type = (c->protocol == VirtualNetworkProtocol::ETHERNET_TAPSERVER)
|
|
? FrameInfo::LinkType::ETHERNET
|
|
: FrameInfo::LinkType::HDLC;
|
|
|
|
if (this->log.debug_f("Virtual network sent frame")) {
|
|
phosg::print_data(stderr, data, size);
|
|
}
|
|
|
|
FrameInfo fi(link_type, data, size);
|
|
if (this->log.should_log(phosg::LogLevel::L_DEBUG)) {
|
|
string fi_header = fi.header_str();
|
|
this->log.debug_f("Frame header: {}", fi_header);
|
|
}
|
|
|
|
if (fi.ether) {
|
|
if (c->mac_addr.is_filled_with(0)) {
|
|
c->mac_addr = fi.ether->src_mac;
|
|
} else if ((fi.ether->src_mac != c->mac_addr) && (fi.ether->src_mac != this->broadcast_mac_address_bytes)) {
|
|
throw runtime_error("client sent IPv4 packet from different MAC address");
|
|
}
|
|
} else if (fi.hdlc) {
|
|
uint16_t expected_checksum = fi.computed_hdlc_checksum();
|
|
uint16_t stored_checksum = fi.stored_hdlc_checksum();
|
|
if (expected_checksum != stored_checksum) {
|
|
throw runtime_error(std::format(
|
|
"HDLC checksum is incorrect ({:04X} expected, {:04X} received)",
|
|
expected_checksum, stored_checksum));
|
|
}
|
|
} else {
|
|
throw runtime_error("frame is not Ethernet or HDLC");
|
|
}
|
|
|
|
if (fi.lcp) {
|
|
co_await this->on_client_lcp_frame(c, fi);
|
|
|
|
} else if (fi.pap) {
|
|
co_await this->on_client_pap_frame(c, fi);
|
|
|
|
} else if (fi.ipcp) {
|
|
co_await this->on_client_ipcp_frame(c, fi);
|
|
|
|
} else if (fi.arp) {
|
|
co_await this->on_client_arp_frame(c, fi);
|
|
|
|
} else if (fi.ipv4) {
|
|
uint16_t expected_ipv4_checksum = fi.computed_ipv4_header_checksum();
|
|
if (fi.ipv4->checksum != expected_ipv4_checksum) {
|
|
throw runtime_error(std::format(
|
|
"IPv4 header checksum is incorrect ({:04X} expected, {:04X} received)",
|
|
expected_ipv4_checksum, fi.ipv4->checksum));
|
|
}
|
|
|
|
if ((fi.ipv4->src_addr != c->ipv4_addr) && (fi.ipv4->src_addr != 0)) {
|
|
throw runtime_error("client sent IPv4 packet from different IPv4 address");
|
|
}
|
|
|
|
if (fi.udp) {
|
|
uint16_t expected_udp_checksum = fi.computed_udp4_checksum();
|
|
if (fi.udp->checksum != expected_udp_checksum) {
|
|
throw runtime_error(std::format(
|
|
"UDP checksum is incorrect ({:04X} expected, {:04X} received)",
|
|
expected_udp_checksum, fi.udp->checksum));
|
|
}
|
|
co_await this->on_client_udp_frame(c, fi);
|
|
|
|
} else if (fi.tcp) {
|
|
uint16_t expected_tcp_checksum = fi.computed_tcp4_checksum();
|
|
if (fi.tcp->checksum != expected_tcp_checksum) {
|
|
throw runtime_error(std::format(
|
|
"TCP checksum is incorrect ({:04X} expected, {:04X} received)",
|
|
expected_tcp_checksum, fi.tcp->checksum));
|
|
}
|
|
co_await this->on_client_tcp_frame(c, fi);
|
|
|
|
} else {
|
|
throw runtime_error("frame uses unsupported IPv4 protocol");
|
|
}
|
|
|
|
} else {
|
|
throw runtime_error("frame is not IPv4");
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_lcp_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
switch (fi.lcp->command) {
|
|
case 0x01: { // Configure-Request
|
|
auto opts_r = fi.read_payload();
|
|
while (!opts_r.eof()) {
|
|
uint8_t opt = opts_r.get_u8();
|
|
string opt_data = opts_r.read(opts_r.get_u8() - 2);
|
|
phosg::StringReader opt_data_r(opt_data);
|
|
switch (opt) {
|
|
case 0x01: // Maximum receive unit
|
|
// TODO: Currently we ignore this, but we probably should use it.
|
|
opt_data_r.get_u16b();
|
|
break;
|
|
case 0x02: // Escaped control character flags
|
|
c->hdlc_escape_control_character_flags = opt_data_r.get_u32b();
|
|
break;
|
|
case 0x05: // Magic-Number
|
|
c->hdlc_remote_magic_number = opt_data_r.get_u32b();
|
|
break;
|
|
case 0x00: // RESERVED
|
|
case 0x03: // Authentication protocol
|
|
case 0x04: // Quality protocol
|
|
case 0x07: // Protocol field compression
|
|
case 0x08: // Address and control field compression
|
|
throw runtime_error(std::format("unimplemented LCP option {:02X} ({} bytes)", opt, opt_data.size()));
|
|
default:
|
|
throw runtime_error("unknown LCP option");
|
|
}
|
|
}
|
|
// Technically, we should implement the LCP state machine, but I'm too
|
|
// lazy to do this right now. In our situation, it should suffice to
|
|
// simply always send a Configure-Request to the client with a magic
|
|
// number not equal to the one we received.
|
|
phosg::StringWriter opts_w;
|
|
opts_w.put_u8(0x01); // Maximum receive unit
|
|
opts_w.put_u8(0x04);
|
|
opts_w.put_u16b(1500);
|
|
opts_w.put_u8(0x02); // Escaped control character flags (we don't require any)
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32(0);
|
|
opts_w.put_u8(0x03); // Authentication protocol
|
|
opts_w.put_u8(0x04);
|
|
opts_w.put_u16b(0xC023); // Password authentication protocol
|
|
opts_w.put_u8(0x05); // Magic number (bitwise inverse of the remote end's)
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(~c->hdlc_remote_magic_number);
|
|
phosg::StringWriter request_w;
|
|
request_w.put<LCPHeader>(LCPHeader{
|
|
.command = 0x01, // Configure-Request
|
|
.request_id = fi.lcp->request_id,
|
|
.size = static_cast<uint16_t>(sizeof(LCPHeader) + opts_w.size()),
|
|
});
|
|
request_w.write(opts_w.str());
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::LCP, request_w.str());
|
|
|
|
phosg::StringWriter ack_w;
|
|
ack_w.put<LCPHeader>(LCPHeader{
|
|
.command = 0x02, // Configure-Ack
|
|
.request_id = fi.lcp->request_id,
|
|
.size = fi.lcp->size,
|
|
});
|
|
ack_w.write(fi.payload, fi.payload_size);
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::LCP, ack_w.str());
|
|
|
|
break;
|
|
}
|
|
|
|
case 0x05: { // Terminate-Request
|
|
c->ipv4_addr = 0;
|
|
c->tcp_connections.clear();
|
|
string response(reinterpret_cast<const char*>(fi.payload), fi.payload_size);
|
|
response.at(0) = 0x06; // Terminate-Ack
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::LCP, response);
|
|
break;
|
|
}
|
|
|
|
case 0x09: { // Echo-Request
|
|
string response(reinterpret_cast<const char*>(fi.payload), fi.payload_size);
|
|
response.at(0) = 0x0A; // Echo-Reply
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::LCP, response);
|
|
break;
|
|
}
|
|
|
|
case 0x0B: // Discard-Request
|
|
case 0x02: // Configure-Ack
|
|
break;
|
|
|
|
case 0x03: // Configure-Nak
|
|
case 0x04: // Configure-Reject
|
|
case 0x06: // Terminate-Ack
|
|
case 0x07: // Code-Reject
|
|
case 0x08: // Protocol-Reject
|
|
case 0x0A: // Echo-Reply
|
|
throw runtime_error("unimplemented LCP command");
|
|
default:
|
|
throw runtime_error("unknown LCP command");
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_pap_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
if (fi.pap->command != 0x01) { // Authenticate-Request
|
|
throw runtime_error("client sent incorrect PAP command");
|
|
}
|
|
|
|
auto r = fi.read_payload();
|
|
string username = r.read(r.get_u8());
|
|
string password = r.read(r.get_u8());
|
|
this->log.info_f("Client logged in with username \"{}\" and password", username);
|
|
|
|
static const string login_message = "newserv PPP simulator";
|
|
phosg::StringWriter w;
|
|
w.put<PAPHeader>(PAPHeader{
|
|
.command = 0x02, // Authenticate-Ack
|
|
.request_id = fi.pap->request_id,
|
|
.size = login_message.size() + sizeof(PAPHeader) + 1,
|
|
});
|
|
w.put_u8(login_message.size());
|
|
w.write(login_message);
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::PAP, w.str());
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_ipcp_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
switch (fi.ipcp->command) {
|
|
case 0x01: { // Configure-Request
|
|
auto opts_r = fi.read_payload();
|
|
|
|
uint32_t remote_ip = 0;
|
|
uint32_t remote_primary_dns = 0;
|
|
uint32_t remote_secondary_dns = 0;
|
|
phosg::StringWriter rejected_opts_w;
|
|
while (!opts_r.eof()) {
|
|
uint8_t opt = opts_r.get_u8();
|
|
string opt_data = opts_r.read(opts_r.get_u8() - 2);
|
|
phosg::StringReader opt_data_r(opt_data);
|
|
switch (opt) {
|
|
case 0x01: // IP addresses (deprecated as of 1992; we don't support it at all)
|
|
throw runtime_error("IPCP client sent IP-Addresses option");
|
|
case 0x02: // IP compression protocol
|
|
rejected_opts_w.put_u8(0x02);
|
|
rejected_opts_w.put_u8(opt_data_r.size() + 2);
|
|
rejected_opts_w.write(opt_data);
|
|
break;
|
|
case 0x03: // IP address
|
|
remote_ip = opt_data_r.get_u32b();
|
|
break;
|
|
case 0x81: // Primary DNS server address
|
|
remote_primary_dns = opt_data_r.get_u32b();
|
|
break;
|
|
case 0x83: // Secondary DNS server address
|
|
remote_secondary_dns = opt_data_r.get_u32b();
|
|
break;
|
|
case 0x82: // Primary NBNS server address
|
|
case 0x84: // Secondary NBNS server address
|
|
case 0x04: // Mobile IP address
|
|
throw runtime_error(std::format("unimplemented IPCP option {:02X} ({} bytes)", opt, opt_data.size()));
|
|
default:
|
|
throw runtime_error("unknown IPCP option");
|
|
}
|
|
}
|
|
|
|
if (!rejected_opts_w.str().empty()) {
|
|
// Send a Configure-Reject if the client specified IP header compression
|
|
phosg::StringWriter reject_w;
|
|
reject_w.put<IPCPHeader>(IPCPHeader{
|
|
.command = 0x04, // Configure-Reject
|
|
.request_id = fi.ipcp->request_id,
|
|
.size = sizeof(IPCPHeader) + rejected_opts_w.size(),
|
|
});
|
|
reject_w.write(rejected_opts_w.str());
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPCP, reject_w.str());
|
|
|
|
} else if ((remote_ip != 0x1E1E1E1E) ||
|
|
(remote_primary_dns != 0x23232323) ||
|
|
(remote_secondary_dns != 0x24242424)) {
|
|
// Send a Configure-Nak if the client's request doesn't exactly match
|
|
// what we want them to use.
|
|
phosg::StringWriter opts_w;
|
|
opts_w.put_u8(0x03); // IP address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x1E1E1E1E);
|
|
opts_w.put_u8(0x81); // Primary DNS server address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x23232323);
|
|
opts_w.put_u8(0x83); // Secondary DNS server address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x24242424);
|
|
|
|
phosg::StringWriter nak_w;
|
|
nak_w.put<IPCPHeader>(IPCPHeader{
|
|
.command = 0x03, // Configure-Nak
|
|
.request_id = fi.ipcp->request_id,
|
|
.size = static_cast<uint16_t>(opts_w.size() + sizeof(IPCPHeader)),
|
|
});
|
|
nak_w.write(opts_w.str());
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPCP, nak_w.str());
|
|
|
|
} else { // Options OK
|
|
c->ipv4_addr = remote_ip;
|
|
|
|
// As with LCP, we technically should implement the state machine, but I
|
|
// continue to be lazy.
|
|
phosg::StringWriter opts_w;
|
|
opts_w.put_u8(0x03); // IP address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x39393939);
|
|
opts_w.put_u8(0x81); // Primary DNS server address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x23232323);
|
|
opts_w.put_u8(0x83); // Secondary DNS server address
|
|
opts_w.put_u8(0x06);
|
|
opts_w.put_u32b(0x24242424);
|
|
|
|
phosg::StringWriter request_w;
|
|
request_w.put<IPCPHeader>(IPCPHeader{
|
|
.command = 0x01, // Configure-Request
|
|
.request_id = fi.ipcp->request_id,
|
|
.size = static_cast<uint16_t>(opts_w.size() + sizeof(IPCPHeader)),
|
|
});
|
|
request_w.write(opts_w.str());
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPCP, request_w.str());
|
|
|
|
phosg::StringWriter ack_w;
|
|
ack_w.put<IPCPHeader>(IPCPHeader{
|
|
.command = 0x02, // Configure-Ack
|
|
.request_id = fi.ipcp->request_id,
|
|
.size = fi.ipcp->size,
|
|
});
|
|
ack_w.write(fi.payload, fi.payload_size);
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPCP, ack_w.str());
|
|
}
|
|
break;
|
|
}
|
|
|
|
case 0x05: { // Terminate-Request
|
|
c->ipv4_addr = 0;
|
|
c->tcp_connections.clear();
|
|
string response(reinterpret_cast<const char*>(fi.payload), fi.payload_size);
|
|
response.at(0) = 0x06; // Terminate-Ack
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::LCP, response);
|
|
break;
|
|
}
|
|
|
|
case 0x02: // Configure-Ack
|
|
break;
|
|
|
|
case 0x03: // Configure-Nak
|
|
case 0x04: // Configure-Reject
|
|
case 0x06: // Terminate-Ack
|
|
case 0x07: // Code-Reject
|
|
throw runtime_error("unimplemented IPCP command");
|
|
default:
|
|
throw runtime_error("unknown LCP command");
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_arp_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
if (fi.arp->hwaddr_len != 6 ||
|
|
fi.arp->paddr_len != 4 ||
|
|
fi.arp->hardware_type != 0x0001 ||
|
|
fi.arp->protocol_type != 0x0800) {
|
|
throw runtime_error("unsupported ARP parameters");
|
|
}
|
|
if (fi.payload_size < 20) {
|
|
throw runtime_error("ARP payload too small");
|
|
}
|
|
|
|
if (c->ipv4_addr == 0) {
|
|
c->ipv4_addr = *reinterpret_cast<const be_uint32_t*>(reinterpret_cast<const uint8_t*>(fi.payload) + 6);
|
|
}
|
|
|
|
phosg::StringWriter w;
|
|
w.put<ARPHeader>(ARPHeader{
|
|
.hardware_type = fi.arp->hardware_type,
|
|
.protocol_type = fi.arp->protocol_type,
|
|
.hwaddr_len = 6,
|
|
.paddr_len = 4,
|
|
.operation = 0x0002,
|
|
});
|
|
|
|
// The incoming payload is:
|
|
// uint8_t src_mac[6]; // MAC address of client
|
|
// uint8_t src_ip[4]; // IP address of client
|
|
// uint8_t dest_mac[6]; // MAC address of host (all zeroes)
|
|
// uint8_t dest_ip[4]; // IP address of host
|
|
// The outgoing payload is:
|
|
// uint8_t dest_mac[6]; // MAC address of host (from configuration)
|
|
// uint8_t dest_ip[4]; // IP address of host
|
|
// uint8_t src_mac[6]; // MAC address of client
|
|
// uint8_t src_ip[4]; // IP address of client
|
|
const char* payload_bytes = reinterpret_cast<const char*>(fi.payload);
|
|
w.write(this->host_mac_address_bytes.data(), 6);
|
|
w.write(payload_bytes + 16, 4);
|
|
w.write(payload_bytes, 10);
|
|
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::ARP, w.str());
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_udp_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
// We only implement DHCP and newserv's DNS server here.
|
|
|
|
// Every received UDP packet will elicit exactly one UDP response from
|
|
// newserv, so we prepare the response headers in advance
|
|
|
|
IPv4Header r_ipv4;
|
|
r_ipv4.version_ihl = 0x45;
|
|
r_ipv4.tos = 0;
|
|
// r_ipv4.size filled in later
|
|
r_ipv4.id = 0;
|
|
r_ipv4.frag_offset = 0;
|
|
r_ipv4.ttl = 20; // TODO: Does this value actually matter? Looks like it just has to be nonzero
|
|
r_ipv4.protocol = 17; // UDP
|
|
// r_ipv4.checksum filled in later
|
|
r_ipv4.src_addr = fi.ipv4->dest_addr;
|
|
r_ipv4.dest_addr = fi.ipv4->src_addr;
|
|
|
|
UDPHeader r_udp;
|
|
r_udp.src_port = fi.udp->dest_port;
|
|
r_udp.dest_port = fi.udp->src_port;
|
|
// r_udp.size filled in later
|
|
// r_udp.checksum filled in later
|
|
|
|
string r_data;
|
|
if (fi.udp->dest_port == 67) { // DHCP
|
|
auto r = fi.read_payload();
|
|
const auto& dhcp = r.get<DHCPHeader>();
|
|
if (dhcp.hardware_type != 1) {
|
|
throw runtime_error("unknown DHCP hardware type");
|
|
}
|
|
if (dhcp.hardware_address_length != 6) {
|
|
throw runtime_error("unknown DHCP hardware address length");
|
|
}
|
|
if (dhcp.magic != 0x63825363) {
|
|
throw runtime_error("incorrect DHCP magic cookie");
|
|
}
|
|
if (dhcp.opcode != 1) { // Request
|
|
throw runtime_error("DHCP packet is not a request");
|
|
}
|
|
|
|
unordered_map<uint8_t, string> option_data;
|
|
for (;;) {
|
|
uint8_t option = r.get_u8();
|
|
if (option == 0xFF) {
|
|
break;
|
|
}
|
|
uint8_t size = r.get_u8();
|
|
option_data.emplace(option, r.read(size));
|
|
}
|
|
|
|
uint8_t command = 0;
|
|
try {
|
|
command = option_data.at(53).at(0);
|
|
} catch (const out_of_range&) {
|
|
throw runtime_error("client did not send a DHCP command option");
|
|
}
|
|
|
|
if (command == 7) {
|
|
// Release IP address (we just ignore these)
|
|
|
|
} else if ((command == 1) || (command == 3)) {
|
|
// Populate the client's addresses
|
|
c->mac_addr = dhcp.client_hardware_address.data();
|
|
c->ipv4_addr = 0x0A000105; // 10.0.1.5
|
|
// In this case, the client doesn't know its IPv4 address or ours yet,
|
|
// so we overwrite the existing fields with the appropriate addresses.
|
|
r_ipv4.src_addr = 0x0A000101; // 10.0.1.1
|
|
r_ipv4.dest_addr = c->ipv4_addr;
|
|
|
|
if ((command != 1) && (command != 3)) {
|
|
throw runtime_error("client sent unknown DHCP command option");
|
|
}
|
|
|
|
phosg::StringWriter w;
|
|
DHCPHeader r_dhcp;
|
|
r_dhcp.opcode = 2; // Response
|
|
r_dhcp.hardware_type = 1; // Ethernet
|
|
r_dhcp.hardware_address_length = 6; // Ethernet
|
|
r_dhcp.hops = 0;
|
|
r_dhcp.transaction_id = dhcp.transaction_id;
|
|
r_dhcp.seconds_elapsed = 0;
|
|
r_dhcp.flags = 0;
|
|
r_dhcp.client_ip_address = 0;
|
|
r_dhcp.your_ip_address = r_ipv4.dest_addr;
|
|
r_dhcp.server_ip_address = r_ipv4.src_addr;
|
|
r_dhcp.gateway_ip_address = 0;
|
|
r_dhcp.client_hardware_address = c->mac_addr;
|
|
r_dhcp.unused_bootp_legacy.clear(0);
|
|
r_dhcp.magic = 0x63825363;
|
|
w.put(r_dhcp);
|
|
// DHCP message type option
|
|
w.put_u8(53);
|
|
w.put_u8(1);
|
|
w.put_u8(static_cast<uint8_t>((command == 3) ? 5 : 2)); // Offer or ack
|
|
// DHCP server ID option
|
|
w.put_u8(54);
|
|
w.put_u8(4);
|
|
w.put_u32b(0x0A000101); // 10.0.1.1
|
|
// Lease time option
|
|
w.put_u8(51);
|
|
w.put_u8(4);
|
|
w.put_u32b(60 * 60 * 24 * 7); // 1 week
|
|
// Renewal time option
|
|
w.put_u8(58);
|
|
w.put_u8(4);
|
|
w.put_u32b(60 * 60 * 24 * 7); // 1 week
|
|
// Rebind time option
|
|
w.put_u8(59);
|
|
w.put_u8(4);
|
|
w.put_u32b(60 * 60 * 24 * 7); // 1 week
|
|
// Subnet mask option
|
|
w.put_u8(1);
|
|
w.put_u8(4);
|
|
w.put_u32b(0xFFFFFF00); // 255.255.255.0
|
|
// Broadcast IP option
|
|
w.put_u8(28);
|
|
w.put_u8(4);
|
|
w.put_u32b(c->ipv4_addr | 0x000000FF);
|
|
// DNS server option
|
|
w.put_u8(6);
|
|
w.put_u8(4);
|
|
w.put_u32b(0x0A000101); // 10.0.1.1
|
|
// Domain name option
|
|
w.put_u8(15);
|
|
w.put_u8(7);
|
|
w.write("newserv");
|
|
// Default gateway option
|
|
w.put_u8(3);
|
|
w.put_u8(4);
|
|
w.put_u32b(0x0A000101); // 10.0.1.1
|
|
// End option list
|
|
w.put_u8(0xFF);
|
|
|
|
r_data = std::move(w.str());
|
|
|
|
} else {
|
|
throw runtime_error("client sent unknown DHCP command");
|
|
}
|
|
|
|
} else if (fi.udp->dest_port == 53) { // DNS
|
|
if (fi.payload_size < 0x0C) {
|
|
throw runtime_error("DNS payload too small");
|
|
}
|
|
|
|
uint32_t resolved_address = this->connect_address_for_remote_address(c->ipv4_addr);
|
|
r_data = DNSServer::response_for_query(fi.payload, fi.payload_size, resolved_address);
|
|
|
|
} else { // Not DHCP or DNS
|
|
throw runtime_error("UDP packet is not DHCP or DNS");
|
|
}
|
|
|
|
if (!r_data.empty()) {
|
|
r_ipv4.size = sizeof(IPv4Header) + sizeof(UDPHeader) + r_data.size();
|
|
r_udp.size = sizeof(UDPHeader) + r_data.size();
|
|
r_ipv4.checksum = FrameInfo::computed_ipv4_header_checksum(r_ipv4);
|
|
r_udp.checksum = FrameInfo::computed_udp4_checksum(
|
|
r_ipv4, r_udp, r_data.data(), r_data.size());
|
|
|
|
if (this->log.should_log(phosg::LogLevel::L_DEBUG)) {
|
|
string remote_str = this->str_for_ipv4_netloc(fi.ipv4->src_addr, fi.udp->src_port);
|
|
this->log.debug_f("Sending UDP response to {}", remote_str);
|
|
phosg::print_data(stderr, r_data);
|
|
}
|
|
|
|
phosg::StringWriter w;
|
|
w.put(r_ipv4);
|
|
w.put(r_udp);
|
|
w.write(r_data);
|
|
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPV4, w.str());
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::on_client_tcp_frame(shared_ptr<IPSSClient> c, const FrameInfo& fi) {
|
|
this->log.debug_f("Virtual network sent TCP frame (seq={:08X}, ack={:08X})",
|
|
fi.tcp->seq_num, fi.tcp->ack_num);
|
|
|
|
if (fi.tcp->flags & (TCPHeader::Flag::NS | TCPHeader::Flag::CWR | TCPHeader::Flag::ECE | TCPHeader::Flag::URG)) {
|
|
throw runtime_error("unsupported flag in TCP packet");
|
|
}
|
|
|
|
if (fi.tcp->flags & TCPHeader::Flag::SYN) {
|
|
// We never make connections back to the client, so we should never receive
|
|
// a SYN+ACK. Essentially, no other flags should be set in any received SYN.
|
|
if ((fi.tcp->flags & 0x0FFF) != TCPHeader::Flag::SYN) {
|
|
throw runtime_error("TCP SYN contains extra flags");
|
|
}
|
|
|
|
phosg::StringReader options_r(fi.tcp + 1, fi.tcp_options_size);
|
|
size_t max_frame_size = 1400;
|
|
while (!options_r.eof()) {
|
|
uint8_t option = options_r.get_u8();
|
|
uint8_t option_size = (option < 2) ? 1 : options_r.get_u8();
|
|
switch (option) {
|
|
case 0: // End of options list
|
|
options_r.go(options_r.size());
|
|
break;
|
|
case 1: // No option (padding)
|
|
break;
|
|
case 2: // Max segment size
|
|
if (option_size != 4) {
|
|
throw runtime_error("incorrect size for TCP max frame size option");
|
|
}
|
|
max_frame_size = options_r.get_u16b();
|
|
break;
|
|
case 3: // Window scale (ignored)
|
|
if (option_size != 3) {
|
|
throw runtime_error("incorrect size for TCP window scale option");
|
|
}
|
|
options_r.skip(option_size);
|
|
break;
|
|
case 4: // Selective ACK supported (ignored)
|
|
if (option_size != 2) {
|
|
throw runtime_error("incorrect size for TCP selective ACK supported option");
|
|
}
|
|
break;
|
|
case 5: // Selective ACK (ignored)
|
|
options_r.skip(option_size - 2);
|
|
break;
|
|
case 8: // Timestamps (ignored)
|
|
if (option_size != 10) {
|
|
throw runtime_error("incorrect size for TCP timestamps option");
|
|
}
|
|
options_r.skip(8);
|
|
break;
|
|
default:
|
|
throw runtime_error("invalid TCP option");
|
|
}
|
|
}
|
|
|
|
shared_ptr<IPSSClient::TCPConnection> conn;
|
|
string conn_str;
|
|
uint64_t key = this->tcp_conn_key_for_client_frame(fi);
|
|
auto conn_it = c->tcp_connections.find(key);
|
|
if (conn_it == c->tcp_connections.end()) {
|
|
conn = make_shared<IPSSClient::TCPConnection>(c);
|
|
c->tcp_connections.emplace(key, conn);
|
|
conn->server_addr = fi.ipv4->dest_addr;
|
|
conn->server_port = fi.tcp->dest_port;
|
|
conn->client_port = fi.tcp->src_port;
|
|
conn->next_client_seq = fi.tcp->seq_num + 1;
|
|
conn->acked_server_seq = phosg::random_object<uint32_t>();
|
|
conn->resend_push_usecs = DEFAULT_RESEND_PUSH_USECS;
|
|
conn->next_push_max_frame_size = max_frame_size;
|
|
conn->max_frame_size = max_frame_size;
|
|
|
|
conn_str = this->str_for_tcp_connection(c, conn);
|
|
this->log.info_f(
|
|
"Client opened TCP connection {} (acked_server_seq={:08X}, next_client_seq={:08X})",
|
|
conn_str, conn->acked_server_seq, conn->next_client_seq);
|
|
|
|
} else {
|
|
conn = conn_it->second;
|
|
|
|
// Connection is NOT new; this is probably a resend of an earlier SYN
|
|
if (!conn->awaiting_first_ack) {
|
|
throw logic_error("SYN received on already-open connection after initial phase");
|
|
}
|
|
// TODO: We should check the syn/ack numbers here instead of just assuming
|
|
// they're correct
|
|
conn_str = this->str_for_tcp_connection(c, conn);
|
|
this->log.debug_f("Client resent SYN for TCP connection {}", conn_str);
|
|
}
|
|
|
|
// Send a SYN+ACK (send_tcp_frame always adds the ACK flag)
|
|
co_await this->send_tcp_frame(c, conn, TCPHeader::Flag::SYN);
|
|
this->log.debug_f("Sent SYN+ACK on {} (acked_server_seq={:08X}, next_client_seq={:08X})",
|
|
conn_str, conn->acked_server_seq, conn->next_client_seq);
|
|
|
|
} else {
|
|
// This frame isn't a SYN, so a connection object should already exist
|
|
uint64_t key = this->tcp_conn_key_for_client_frame(fi);
|
|
auto conn_it = c->tcp_connections.find(key);
|
|
if (conn_it == c->tcp_connections.end()) {
|
|
throw runtime_error("non-SYN frame does not correspond to any open TCP connection");
|
|
}
|
|
auto& conn = conn_it->second;
|
|
bool conn_valid = true;
|
|
bool acked_seq_changed = false;
|
|
|
|
if (fi.tcp->flags & TCPHeader::Flag::ACK) {
|
|
this->log.debug_f("Client sent ACK {:08X}", fi.tcp->ack_num);
|
|
if (conn->awaiting_first_ack) {
|
|
if (fi.tcp->ack_num != conn->acked_server_seq + 1) {
|
|
throw runtime_error("first ack_num was not acked_server_seq + 1");
|
|
}
|
|
conn->acked_server_seq++;
|
|
conn->awaiting_first_ack = false;
|
|
|
|
} else {
|
|
conn->awaiting_ack = false;
|
|
if (seq_num_greater(fi.tcp->ack_num, conn->acked_server_seq)) {
|
|
this->log.debug_f("Advancing acked_server_seq from {:08X}", conn->acked_server_seq);
|
|
uint32_t ack_delta = fi.tcp->ack_num - conn->acked_server_seq;
|
|
if (conn->outbound_data_bytes < ack_delta) {
|
|
throw runtime_error("client acknowledged beyond end of sent data");
|
|
}
|
|
|
|
conn->drain_outbound_data(ack_delta);
|
|
conn->acked_server_seq += ack_delta;
|
|
conn->resend_push_usecs = DEFAULT_RESEND_PUSH_USECS;
|
|
conn->next_push_max_frame_size = conn->max_frame_size;
|
|
acked_seq_changed = true;
|
|
|
|
this->log.debug_f(
|
|
"Removed {:08X} bytes from pending buffer and advanced acked_server_seq to {:08X}",
|
|
ack_delta, conn->acked_server_seq);
|
|
|
|
} else if (seq_num_less(fi.tcp->ack_num, conn->acked_server_seq)) {
|
|
throw runtime_error("client sent lower ack num than previous frame");
|
|
}
|
|
}
|
|
|
|
if (!conn->server_channel) {
|
|
co_await this->open_server_connection(c, conn);
|
|
}
|
|
}
|
|
|
|
if (fi.tcp->flags & (TCPHeader::Flag::RST | TCPHeader::Flag::FIN)) {
|
|
bool is_rst = (fi.tcp->flags & TCPHeader::Flag::RST);
|
|
if (is_rst && (fi.tcp->flags & TCPHeader::Flag::FIN)) {
|
|
throw runtime_error("client sent TCP FIN+RST");
|
|
}
|
|
|
|
string conn_str = this->str_for_tcp_connection(c, conn);
|
|
this->log.info_f("Client closed TCP connection {}", conn_str);
|
|
if (conn->server_channel) {
|
|
conn->server_channel->disconnect();
|
|
conn->server_channel.reset();
|
|
}
|
|
|
|
// TODO: Are we supposed to send a response to an RST? Here we do, and the
|
|
// client probably just ignores it anyway
|
|
co_await this->send_tcp_frame(c, conn, fi.tcp->flags & (TCPHeader::Flag::RST | TCPHeader::Flag::FIN));
|
|
|
|
// Delete the connection object. The unique_ptr destructor flushes the
|
|
// bufferevent, and thereby sends an EOF to the server's end.
|
|
c->tcp_connections.erase(key);
|
|
conn_valid = false;
|
|
|
|
} else if (fi.payload_size != 0) {
|
|
// Note: The PSH flag isn't required to be set on all packets that
|
|
// contain data. The PSH flag just means "tell the application that data
|
|
// is available", so some senders only set the PSH flag on the last frame
|
|
// of a large segment of data, since the application wouldn't be able to
|
|
// process the segment until all of it is available. newserv can handle
|
|
// incomplete commands, so we just ignore the PSH flag and forward any
|
|
// data to the server immediately (hence the lack of a flag check in the
|
|
// above condition).
|
|
|
|
string conn_str = this->log.should_log(phosg::LogLevel::L_WARNING)
|
|
? this->str_for_tcp_connection(c, conn)
|
|
: "";
|
|
|
|
size_t payload_skip_bytes;
|
|
if (fi.tcp->seq_num == conn->next_client_seq) {
|
|
payload_skip_bytes = 0;
|
|
|
|
} else if (seq_num_less(fi.tcp->seq_num, conn->next_client_seq)) {
|
|
// If the frame overlaps an existing boundary, we'll accept some of the
|
|
// data; otherwise we'll ignore it entirely (but still send an ACK)
|
|
uint32_t end_seq = fi.tcp->seq_num + fi.payload_size;
|
|
if (seq_num_less_or_equal(end_seq, conn->next_client_seq)) { // Fully "in the past"
|
|
payload_skip_bytes = fi.payload_size;
|
|
} else { // Partially "in the past"
|
|
payload_skip_bytes = fi.payload_size - (end_seq - conn->next_client_seq);
|
|
}
|
|
|
|
} else {
|
|
// Payload is in the future - we must have missed a data frame. We'll
|
|
// ignore it (but warn) and send an ACK later, and the client should
|
|
// retransmit the lost data
|
|
this->log.warning_f(
|
|
"Client sent out-of-order sequence number (expected {:08X}, received {:08X}, 0x{:X} data bytes)",
|
|
conn->next_client_seq, fi.tcp->seq_num, fi.payload_size);
|
|
payload_skip_bytes = fi.payload_size;
|
|
}
|
|
|
|
if (payload_skip_bytes > fi.payload_size) {
|
|
throw logic_error("payload skip bytes too large");
|
|
}
|
|
|
|
if (payload_skip_bytes < fi.payload_size) {
|
|
const void* payload = reinterpret_cast<const uint8_t*>(fi.payload) + payload_skip_bytes;
|
|
size_t payload_size = fi.payload_size - payload_skip_bytes;
|
|
|
|
bool was_logged;
|
|
if (payload_skip_bytes) {
|
|
was_logged = this->log.debug_f(
|
|
"Client sent data on TCP connection {}, overlapping existing ack'ed data (0x{:X} bytes ignored)",
|
|
conn_str, payload_skip_bytes);
|
|
} else {
|
|
was_logged = this->log.debug_f("Client sent data on TCP connection {}", conn_str);
|
|
}
|
|
if (was_logged) {
|
|
phosg::print_data(stderr, payload, payload_size);
|
|
}
|
|
|
|
// Send the new data to the server
|
|
if (!conn->server_channel) {
|
|
this->log.warning_f("Client sent data on TCP connection {}, but server channel is missing",
|
|
conn_str);
|
|
} else if (!conn->server_channel->connected()) {
|
|
this->log.warning_f("Client sent data on TCP connection {}, but server channel is disconnected",
|
|
conn_str);
|
|
} else {
|
|
conn->server_channel->add_inbound_data(payload, payload_size);
|
|
}
|
|
|
|
// Update the sequence number and stats
|
|
conn->next_client_seq += payload_size;
|
|
conn->bytes_received += payload_size;
|
|
if (conn->next_client_seq < payload_size) {
|
|
this->log.warning_f("Client sequence number has wrapped (next={:08X}, bytes={:X})",
|
|
fi.tcp->seq_num, payload_size);
|
|
}
|
|
}
|
|
|
|
// Send an ACK
|
|
co_await this->send_tcp_frame(c, conn);
|
|
this->log.debug_f("Sent PSH ACK on {} (acked_server_seq={:08X}, next_client_seq={:08X}, bytes_received=0x{:X})",
|
|
conn_str, conn->acked_server_seq, conn->next_client_seq, conn->bytes_received);
|
|
}
|
|
|
|
if (conn_valid && acked_seq_changed) {
|
|
// Try to send some more data if the client is waiting on it
|
|
this->schedule_send_pending_push_frame(conn, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
void IPStackSimulator::schedule_send_pending_push_frame(shared_ptr<IPSSClient::TCPConnection> conn, uint64_t delay_usecs) {
|
|
conn->resend_push_timer.expires_after(std::chrono::microseconds(delay_usecs));
|
|
conn->resend_push_timer.async_wait([wconn = weak_ptr<IPSSClient::TCPConnection>(conn)](std::error_code ec) {
|
|
if (ec) {
|
|
return;
|
|
}
|
|
auto conn = wconn.lock();
|
|
if (!conn) {
|
|
return;
|
|
}
|
|
auto c = conn->client.lock();
|
|
if (!c) {
|
|
return;
|
|
}
|
|
auto sim = c->sim.lock();
|
|
if (!sim) {
|
|
return;
|
|
}
|
|
asio::co_spawn(*sim->get_io_context(), sim->send_pending_push_frame(c, conn), asio::detached);
|
|
});
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::send_pending_push_frame(
|
|
shared_ptr<IPSSClient> c, shared_ptr<IPSSClient::TCPConnection> conn) {
|
|
if (!conn->outbound_data_bytes) {
|
|
if (!conn->server_channel || !conn->server_channel->connected()) {
|
|
co_await this->close_tcp_connection(c, conn);
|
|
}
|
|
co_return;
|
|
}
|
|
|
|
size_t bytes_to_send = min<size_t>(conn->outbound_data_bytes, conn->next_push_max_frame_size);
|
|
if (c->protocol == VirtualNetworkProtocol::HDLC_TAPSERVER) {
|
|
// There is a bug in Dolphin's modem implementation (which I wrote, so it's
|
|
// my fault) that causes commands to be dropped when too much data is sent
|
|
// at once. To work around this, we only send up to 200 bytes in each push
|
|
// frame.
|
|
bytes_to_send = min<size_t>(bytes_to_send, 200);
|
|
}
|
|
|
|
this->log.debug_f("Sending PSH frame with seq_num {:08X}, 0x{:X}/0x{:X} data bytes",
|
|
conn->acked_server_seq, bytes_to_send, conn->outbound_data_bytes);
|
|
|
|
conn->linearize_outbound_data(bytes_to_send);
|
|
if (conn->outbound_data.empty() || conn->outbound_data.front().size() < bytes_to_send) {
|
|
// This should never happen because bytes_to_send should always be less
|
|
// than or equal to conn->outbound_data_bytes, which itself should be equal
|
|
// to the number of bytes that can be linearized
|
|
throw logic_error("failed to linearize enough bytes before sending TCP PSH");
|
|
}
|
|
co_await this->send_tcp_frame(c, conn, TCPHeader::Flag::PSH, conn->outbound_data.front().data(), bytes_to_send);
|
|
conn->awaiting_ack = true;
|
|
|
|
// Schedule the timer for sending another PSH, in case the client doesn't
|
|
// respond quickly enough
|
|
this->schedule_send_pending_push_frame(conn, conn->resend_push_usecs);
|
|
|
|
// If the client isn't responding to our PSHes, back off exponentially up to
|
|
// a limit of 5 seconds between PSH frames. This window is reset when
|
|
// acked_server_seq changes (that is, when the client has acknowledged any new
|
|
// data). It seems some situations cause GameCube clients to drop packets more
|
|
// often; to alleviate this, we also try to resend less data.
|
|
conn->resend_push_usecs *= 2;
|
|
if (conn->resend_push_usecs > 5000000) {
|
|
conn->resend_push_usecs = 5000000;
|
|
}
|
|
conn->next_push_max_frame_size = max<size_t>(0x100, conn->next_push_max_frame_size - 0x100);
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::send_tcp_frame(
|
|
shared_ptr<IPSSClient> c,
|
|
shared_ptr<IPSSClient::TCPConnection> conn,
|
|
uint16_t flags,
|
|
const void* payload_data,
|
|
size_t payload_size) {
|
|
if (!payload_data != !(flags & TCPHeader::Flag::PSH)) {
|
|
throw logic_error("data should be given if and only if PSH is given");
|
|
}
|
|
|
|
IPv4Header ipv4;
|
|
ipv4.version_ihl = 0x45;
|
|
ipv4.tos = 0;
|
|
// ipv4.size filled in later
|
|
ipv4.id = 0;
|
|
ipv4.frag_offset = 0;
|
|
ipv4.ttl = 20;
|
|
ipv4.protocol = 6; // TCP
|
|
// ipv4.checksum filled in later
|
|
ipv4.src_addr = conn->server_addr;
|
|
ipv4.dest_addr = c->ipv4_addr;
|
|
|
|
TCPHeader tcp;
|
|
tcp.src_port = conn->server_port;
|
|
tcp.dest_port = conn->client_port;
|
|
tcp.seq_num = conn->acked_server_seq;
|
|
tcp.ack_num = conn->next_client_seq;
|
|
tcp.flags = (5 << 12) | TCPHeader::Flag::ACK | flags;
|
|
tcp.window = 0x1000;
|
|
tcp.urgent_ptr = 0;
|
|
// tcp.checksum filled in later
|
|
|
|
ipv4.size = sizeof(IPv4Header) + sizeof(TCPHeader) + payload_size;
|
|
ipv4.checksum = FrameInfo::computed_ipv4_header_checksum(ipv4);
|
|
tcp.checksum = FrameInfo::computed_tcp4_checksum(ipv4, tcp, payload_data, payload_size);
|
|
|
|
phosg::StringWriter w;
|
|
w.put(ipv4);
|
|
w.put(tcp);
|
|
if (payload_data) {
|
|
w.write(payload_data, payload_size);
|
|
}
|
|
|
|
co_await this->send_layer3_frame(c, FrameInfo::Protocol::IPV4, w.str());
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::open_server_connection(
|
|
shared_ptr<IPSSClient> c, shared_ptr<IPSSClient::TCPConnection> conn) {
|
|
if (conn->server_channel) {
|
|
throw logic_error("server connection is already open");
|
|
}
|
|
|
|
string conn_str = this->str_for_tcp_connection(c, conn);
|
|
|
|
// Figure out which logical port the connection should go to
|
|
auto port_config_it = this->state->number_to_port_config.find(conn->server_port);
|
|
if (port_config_it == this->state->number_to_port_config.end()) {
|
|
this->log.error_f("TCP connection {} is to undefined port {}", conn_str, conn->server_port);
|
|
co_await this->close_tcp_connection(c, conn);
|
|
co_return;
|
|
}
|
|
const auto& port_config = port_config_it->second;
|
|
|
|
conn->server_channel = make_shared<IPSSChannel>(this->shared_from_this(), c, conn, port_config->version, 1);
|
|
|
|
if (!this->state->game_server.get()) {
|
|
this->log.error_f("No server available for TCP connection {}", conn_str);
|
|
co_await this->close_tcp_connection(c, conn);
|
|
co_return;
|
|
} else {
|
|
this->state->game_server->connect_channel(conn->server_channel, conn->server_port, port_config->behavior);
|
|
this->log.info_f("Connected TCP connection {} to game server", conn_str);
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::close_tcp_connection(
|
|
shared_ptr<IPSSClient> c, shared_ptr<IPSSClient::TCPConnection> conn) {
|
|
// Send an RST to the client. This is kind of rude (we really should use FIN)
|
|
// but the PSO network stack always sends an RST to us when disconnecting, so
|
|
// whatever
|
|
co_await this->send_tcp_frame(c, conn, TCPHeader::Flag::RST);
|
|
|
|
// Delete the connection object
|
|
string conn_str = this->str_for_tcp_connection(c, conn);
|
|
this->log.info_f("Server closed TCP connection {}", conn_str);
|
|
c->tcp_connections.erase(this->tcp_conn_key_for_connection(conn));
|
|
}
|
|
|
|
std::shared_ptr<IPSSClient> IPStackSimulator::create_client(
|
|
std::shared_ptr<IPSSSocket> listen_sock, asio::ip::tcp::socket&& client_sock) {
|
|
uint32_t addr = ipv4_addr_for_asio_addr(client_sock.remote_endpoint().address());
|
|
if (this->state->banned_ipv4_ranges->check(addr)) {
|
|
client_sock.close();
|
|
return nullptr;
|
|
}
|
|
|
|
uint64_t network_id = this->next_network_id++;
|
|
this->log.info_f("Virtual network N-{:X} connected via {}", network_id, listen_sock->name);
|
|
return make_shared<IPSSClient>(this->shared_from_this(), network_id, listen_sock->protocol, std::move(client_sock));
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::handle_tapserver_client(std::shared_ptr<IPSSClient> c) {
|
|
for (;;) {
|
|
le_uint16_t frame_size;
|
|
co_await asio::async_read(c->sock, asio::buffer(&frame_size, sizeof(frame_size)), asio::use_awaitable);
|
|
string frame(frame_size, '\0');
|
|
co_await asio::async_read(c->sock, asio::buffer(frame.data(), frame.size()), asio::use_awaitable);
|
|
|
|
if (c->protocol == VirtualNetworkProtocol::HDLC_TAPSERVER) {
|
|
frame.resize(unescape_hdlc_frame_inplace(frame.data(), frame.size()));
|
|
}
|
|
|
|
try {
|
|
co_await this->on_client_frame(c, frame.data(), frame.size());
|
|
} catch (const exception& e) {
|
|
if (this->log.warning_f("Failed to process frame: {}", e.what())) {
|
|
phosg::print_data(stderr, frame);
|
|
}
|
|
}
|
|
|
|
c->reschedule_idle_timeout();
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::handle_hdlc_raw_client(std::shared_ptr<IPSSClient> c) {
|
|
std::string buffer(0x1000, 0);
|
|
size_t buffer_bytes = 0;
|
|
for (;;) {
|
|
size_t req_buffer_size = buffer_bytes + 0x400;
|
|
if (buffer.size() < req_buffer_size) {
|
|
buffer.resize(req_buffer_size);
|
|
}
|
|
|
|
auto buf = asio::buffer(buffer.data() + buffer_bytes, buffer.size() - buffer_bytes);
|
|
buffer_bytes += co_await c->sock.async_read_some(buf, asio::use_awaitable);
|
|
|
|
// Process as many packets as possible
|
|
size_t frame_start_offset = 0;
|
|
while (buffer.size() > frame_start_offset) {
|
|
if (buffer[frame_start_offset] != 0x7E) {
|
|
throw runtime_error("HDLC frame does not begin with 7E");
|
|
}
|
|
size_t frame_end_offset = buffer.find(0x7E, frame_start_offset + 1);
|
|
if (frame_end_offset == string::npos) {
|
|
break;
|
|
}
|
|
frame_end_offset++;
|
|
|
|
// Unescaping a frame can't make it longer, so we just do it in-place
|
|
void* frame_data = buffer.data() + frame_start_offset;
|
|
size_t unescaped_size = unescape_hdlc_frame_inplace(frame_data, frame_end_offset - frame_start_offset);
|
|
|
|
try {
|
|
co_await this->on_client_frame(c, frame_data, unescaped_size);
|
|
} catch (const exception& e) {
|
|
if (this->log.warning_f("Failed to process frame: {}", e.what())) {
|
|
phosg::print_data(stderr, frame_data, unescaped_size);
|
|
}
|
|
}
|
|
|
|
frame_start_offset = frame_end_offset;
|
|
}
|
|
|
|
// Delete the processed packets from the beginning of the buffer
|
|
if (frame_start_offset > buffer_bytes) {
|
|
throw logic_error("frame start offset is beyond buffer bounds");
|
|
} else if (frame_start_offset == buffer_bytes) {
|
|
buffer_bytes = 0;
|
|
} else if (frame_start_offset > 0) {
|
|
memcpy(buffer.data(), buffer.data() + frame_start_offset, buffer_bytes - frame_start_offset);
|
|
buffer_bytes -= frame_start_offset;
|
|
}
|
|
|
|
// Reset the idle timer, since the client has sent something valid
|
|
c->reschedule_idle_timeout();
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::handle_client(std::shared_ptr<IPSSClient> c) {
|
|
switch (c->protocol) {
|
|
case VirtualNetworkProtocol::ETHERNET_TAPSERVER:
|
|
case VirtualNetworkProtocol::HDLC_TAPSERVER:
|
|
co_await this->handle_tapserver_client(c);
|
|
break;
|
|
case VirtualNetworkProtocol::HDLC_RAW:
|
|
co_await this->handle_hdlc_raw_client(c);
|
|
break;
|
|
default:
|
|
throw std::logic_error("unknown virtual network protocol");
|
|
}
|
|
}
|
|
|
|
asio::awaitable<void> IPStackSimulator::destroy_client(std::shared_ptr<IPSSClient> c) {
|
|
this->log.info_f("Virtual network N-{:X} disconnected ({} TCP connections to close)", c->network_id, c->tcp_connections.size());
|
|
for (const auto& [conn_id, conn] : c->tcp_connections) {
|
|
if (conn->server_channel) {
|
|
this->log.info_f("Closing TCP connection {:016X} on N-{:X}", conn_id, c->network_id);
|
|
conn->server_channel->disconnect();
|
|
conn->server_channel.reset();
|
|
} else {
|
|
this->log.info_f("TCP connection {:016X} on N-{:X} has no server channel", conn_id, c->network_id);
|
|
}
|
|
}
|
|
|
|
co_return;
|
|
}
|