RS232Net.cc

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#include "RS232Net.hh"
 
#include "RS232Connector.hh"
 
#include "PlugException.hh"
#include "EventDistributor.hh"
#include "Scheduler.hh"
#include "serialize.hh"
 
#include "checked_cast.hh"
#include "ranges.hh"
#include "StringOp.hh"
 
#include <array>
#include <bit>
#include <cassert>
#ifndef _WIN32
#include <netdb.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>
#endif
 
namespace openmsx {
 
// IP232 protocol
static constexpr char IP232_MAGIC    = '\xff';
 
// sending
static constexpr char IP232_DTR_LO   = '\x00';
static constexpr char IP232_DTR_HI   = '\x01';
 
// receiving
static constexpr char IP232_DCD_LO   = '\x00';
static constexpr char IP232_DCD_HI   = '\x01';
static constexpr char IP232_DCD_MASK = '\x01';
 
static constexpr char IP232_RI_LO    = '\x00';
static constexpr char IP232_RI_HI    = '\x02';
static constexpr char IP232_RI_MASK  = '\x02';
 
RS232Net::RS232Net(EventDistributor& eventDistributor_,
                         Scheduler& scheduler_,
                         CommandController& commandController)
        : eventDistributor(eventDistributor_), scheduler(scheduler_)
        , rs232NetAddressSetting(
                commandController, "rs232-net-address",
                "IP/address:port for RS232 net pluggable",
                "127.0.0.1:25232")
        , rs232NetUseIP232(
                commandController, "rs232-net-ip232",
                "Enable IP232 protocol",
                true)
{
        eventDistributor.registerEventListener(EventType::RS232_NET, *this);
}
 
RS232Net::~RS232Net()
{
        eventDistributor.unregisterEventListener(EventType::RS232_NET, *this);
}
 
// Parse a IPv6 or IPv4 address string.
//
// The address must be specified in one of the forms:
//   <host>
//   <host>:port
//   [<hostipv6>]:<port>
// with:
//   <hostname> being the name of the host,
//   <hostipv6> being the IP of the host, and
//   <host>     being the name of the host or its IPv6,
//   <port>     being the port number.
//
// The extra braces [...] in case the port is specified are needed as IPv6
// addresses themselves already contain colons, and it would be impossible to
// clearly distinguish between an IPv6 address, and an IPv6 address where a port
// has been specified. This format is a common one.
static std::optional<RS232Net::NetworkSocketAddress> parseNetworkAddress(std::string_view address)
{
        if (address.empty()) {
                // There was no address given, do not try to process it.
                return {};
        }
 
        // Preset the socket address
        RS232Net::NetworkSocketAddress result;
        memset(&result.address, 0, sizeof(result.address));
 
        struct addrinfo hints;
        memset(&hints, 0, sizeof(hints));
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = IPPROTO_TCP;
 
        auto setIPv4 = [&] {
                hints.ai_family = AF_INET;
                result.domain = PF_INET;
                result.len = sizeof(result.address.ipv4);
                result.address.ipv4.sin_family = AF_INET;
                result.address.ipv4.sin_port = 0;
                result.address.ipv4.sin_addr.s_addr = INADDR_ANY;
        };
        auto setIPv6 = [&] {
                hints.ai_family = AF_INET6;
                result.domain = PF_INET6;
                result.len = sizeof(result.address.ipv6);
                result.address.ipv6.sin6_family = AF_INET6;
                result.address.ipv6.sin6_port = 0;
                result.address.ipv6.sin6_addr = in6addr_any;
        };
 
        // Parse 'address', fills in 'addressPart' and 'portPart'
        std::string addressPart;
        std::string portPart;
        auto [ipv6_address_part, ipv6_port_part] = StringOp::splitOnFirst(address, ']');
        if (!ipv6_port_part.empty()) { // there was a ']' character (and it's already dropped)
                // Try to parse as: "[IPv6]:port"
                if (!ipv6_address_part.starts_with('[') || !ipv6_port_part.starts_with(':')) {
                        // Malformed address, do not try to process it.
                        return {};
                }
                addressPart = std::string(ipv6_address_part.substr(1)); // drop '['
                portPart    = std::string(ipv6_port_part   .substr(1)); // drop ':'
                setIPv6();
        } else {
                auto numColons = ranges::count(address, ':');
                if (numColons == 0) {
                        // either IPv4 or IPv6
                        addressPart = std::string(address);
                } else if (numColons == 1) {
                        // ipv4:port
                        auto [ipv4_address_part, ipv4_port_part] = StringOp::splitOnFirst(address, ':');
                        addressPart = std::string(ipv4_address_part);
                        portPart    = std::string(ipv4_port_part);
                        setIPv4();
                } else {
                        // ipv6 address
                        addressPart = std::string(address);
                        setIPv6();
                }
        }
 
        // Interpret 'addressPart' and 'portPart' (possibly the latter is empty)
        struct addrinfo* res;
        if (getaddrinfo(addressPart.c_str(), portPart.c_str(), &hints, &res) != 0) {
                return {};
        }
 
        memcpy(&result.address, res->ai_addr, res->ai_addrlen);
        freeaddrinfo(res);
        return result;
}
 
// Pluggable
void RS232Net::plugHelper(Connector& connector_, EmuTime::param /*time*/)
{
        auto address = rs232NetAddressSetting.getString();
        auto socketAddress = parseNetworkAddress(address);
        if (!socketAddress) {
                throw PlugException("Incorrect address / could not resolve: ", address);
        }
        open_socket(*socketAddress);
        if (sockfd == OPENMSX_INVALID_SOCKET) {
                throw PlugException("Can't open connection");
        }
 
        DTR = false;
        RTS = true;
        DCD = false;
        RI  = false;
        IP232 = rs232NetUseIP232.getBoolean();
 
        auto& rs232Connector = checked_cast<RS232Connector&>(connector_);
        rs232Connector.setDataBits(SerialDataInterface::DataBits::D8); // 8 data bits
        rs232Connector.setStopBits(SerialDataInterface::StopBits::S1); // 1 stop bit
        rs232Connector.setParityBit(false, SerialDataInterface::Parity::EVEN); // no parity
 
        setConnector(&connector_); // base class will do this in a moment,
                                   // but thread already needs it
        poller.reset();
        thread = std::thread([this]() { run(); });
}
 
void RS232Net::unplugHelper(EmuTime::param /*time*/)
{
        // close socket
        if (sockfd != OPENMSX_INVALID_SOCKET) {
                if (IP232) {
                        static constexpr std::array<char, 2> dtr_lo = {IP232_MAGIC, IP232_DTR_LO};
                        net_put(dtr_lo);
                }
                sock_close(sockfd);
                sockfd = OPENMSX_INVALID_SOCKET;
        }
        // stop helper thread
        poller.abort();
        if (thread.joinable()) thread.join();
}
 
std::string_view RS232Net::getName() const
{
        return "rs232-net";
}
 
std::string_view RS232Net::getDescription() const
{
        return "RS232 Network pluggable. Connects the RS232 port to IP:PORT, "
               "selected with the 'rs232-net-address' setting.";
}
 
void RS232Net::run()
{
        bool ipMagic = false;
        while (true) {
                if (sockfd == OPENMSX_INVALID_SOCKET) break;
#ifndef _WIN32
                if (poller.poll(sockfd)) {
                        break; // error or abort
                }
#endif
                char b;
                auto n = sock_recv(sockfd, &b, sizeof(b));
                if (n < 0) { // error
                        sock_close(sockfd);
                        sockfd = OPENMSX_INVALID_SOCKET;
                        break;
                } else if (n == 0) { // no data, try again
                        continue;
                }
 
                // Process received byte
                if (IP232) {
                        if (ipMagic) {
                                ipMagic = false;
                                if (b != IP232_MAGIC) {
                                        DCD = (b & IP232_DCD_MASK) == IP232_DCD_HI;
                                        // RI implemented in TCPSer 1.1.5 (not yet released)
                                        // RI present at least on Sony HBI-232 and HB-G900AP (bit 1 of &H82/&HBFFA status register)
                                        //    missing on SVI-738
                                        RI = (b & IP232_RI_MASK) == IP232_RI_HI;
                                        continue;
                                }
                                // was a literal 0xff
                        } else {
                                if (b == IP232_MAGIC) {
                                        ipMagic = true;
                                        continue;
                                }
                        }
                }
 
                // Put received byte in queue and notify main emulation thread
                assert(isPluggedIn());
                {
                        std::scoped_lock lock(mutex);
                        queue.push_back(b);
                }
                eventDistributor.distributeEvent(Rs232NetEvent());
        }
}
 
// input
void RS232Net::signal(EmuTime::param time)
{
        auto* conn = checked_cast<RS232Connector*>(getConnector());
 
        if (!conn->acceptsData()) {
                std::scoped_lock lock(mutex);
                queue.clear();
                return;
        }
 
        if (!conn->ready() || !RTS) return;
 
        std::scoped_lock lock(mutex);
        if (queue.empty()) return;
        char b = queue.pop_front();
        conn->recvByte(b, time);
}
 
// EventListener
bool RS232Net::signalEvent(const Event& /*event*/)
{
        if (isPluggedIn()) {
                signal(scheduler.getCurrentTime());
        } else {
                std::scoped_lock lock(mutex);
                queue.clear();
        }
        return false;
}
 
// output
void RS232Net::recvByte(uint8_t value_, EmuTime::param /*time*/)
{
        if (sockfd == OPENMSX_INVALID_SOCKET) return;
 
        auto value = static_cast<char>(value_);
        if ((value == IP232_MAGIC) && IP232) {
                static constexpr std::array<char, 2> ff = {IP232_MAGIC, IP232_MAGIC};
                net_put(ff);
        } else {
                net_put(std::span{&value, 1});
        }
}
 
// Control lines
 
std::optional<bool> RS232Net::getDSR(EmuTime::param /*time*/) const
{
        return true; // Needed to set this line in the correct state for a plugged device
}
 
std::optional<bool> RS232Net::getCTS(EmuTime::param /*time*/) const
{
        return true; // TODO: Implement when IP232 adds support for CTS
}
 
std::optional<bool> RS232Net::getDCD(EmuTime::param /*time*/) const
{
        return DCD;
}
 
std::optional<bool> RS232Net::getRI(EmuTime::param /*time*/) const
{
        return RI;
}
 
void RS232Net::setDTR(bool status, EmuTime::param /*time*/)
{
        if (DTR == status) return;
        DTR = status;
 
        if (sockfd == OPENMSX_INVALID_SOCKET) return;
        if (IP232) {
                std::array<char, 2> dtr = {IP232_MAGIC, DTR ? IP232_DTR_HI : IP232_DTR_LO};
                net_put(dtr);
        }
}
 
void RS232Net::setRTS(bool status, EmuTime::param /*time*/)
{
        if (RTS == status) return;
        RTS = status;
        if (RTS) {
                std::scoped_lock lock(mutex);
                if (!queue.empty()) {
                        eventDistributor.distributeEvent(Rs232NetEvent());
                }
        }
}
 
// Socket routines below based on VICE emulator socket.c
bool RS232Net::net_put(std::span<const char> buf)
{
        assert(sockfd != OPENMSX_INVALID_SOCKET);
 
        if (auto n = sock_send(sockfd, buf.data(), buf.size()); n < 0) {
                sock_close(sockfd);
                sockfd = OPENMSX_INVALID_SOCKET;
                return false;
        }
        return true;
}
 
// Open a socket and initialise it for client operation
void RS232Net::open_socket(const NetworkSocketAddress& socket_address)
{
        sockfd = socket(socket_address.domain, SOCK_STREAM, IPPROTO_TCP);
        if (sockfd == OPENMSX_INVALID_SOCKET) return;
 
        int one = 1;
        setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, std::bit_cast<char*>(&one), sizeof(one));
 
        if (connect(sockfd, &socket_address.address.generic, socket_address.len) < 0) {
                sock_close(sockfd);
                sockfd = OPENMSX_INVALID_SOCKET;
        }
}
 
template<typename Archive>
void RS232Net::serialize(Archive& /*ar*/, unsigned /*version*/)
{
        // don't try to resume a previous logfile (see PrinterPortLogger)
}
INSTANTIATE_SERIALIZE_METHODS(RS232Net);
REGISTER_POLYMORPHIC_INITIALIZER(Pluggable, RS232Net, "RS232Net");
 
} // namespace openmsx