/*

* (C) 2015,2016,2017 Jack Lloyd

* (C) 2016 Daniel Neus

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/socket.h>

#include <botan/exceptn.h>

#include <botan/mem_ops.h>

#include <chrono>

#if defined(BOTAN_HAS_BOOST_ASIO)

  /*

  * We don't need serial port support anyway, and asking for it causes

  * macro conflicts with termios.h when this file is included in the

  * amalgamation.

  */

  #define BOOST_ASIO_DISABLE_SERIAL_PORT

  #include <boost/asio.hpp>

  #include <boost/asio/system_timer.hpp>

#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS)

  #include <sys/socket.h>

  #include <sys/time.h>

  #include <netinet/in.h>

  #include <netdb.h>

  #include <string.h>

  #include <unistd.h>

  #include <errno.h>

  #include <fcntl.h>

#elif defined(BOTAN_TARGET_OS_HAS_WINSOCK2)

  #include <ws2tcpip.h>

#endif

namespace Botan {

namespace {

#if defined(BOTAN_HAS_BOOST_ASIO)

class Asio_Socket final : public OS::Socket

   {

   public:

      Asio_Socket(const std::string& hostname,

                  const std::string& service,

                  std::chrono::milliseconds timeout) :

         m_timeout(timeout), m_timer(m_io), m_tcp(m_io)

         {

         m_timer.expires_from_now(m_timeout);

         check_timeout();

         boost::asio::ip::tcp::resolver resolver(m_io);

         boost::asio::ip::tcp::resolver::query query(hostname, service);

         boost::asio::ip::tcp::resolver::iterator dns_iter = resolver.resolve(query);

         boost::system::error_code ec = boost::asio::error::would_block;

         auto connect_cb = [&ec](const boost::system::error_code& e,

                                 boost::asio::ip::tcp::resolver::iterator) { ec = e; };

         boost::asio::async_connect(m_tcp, dns_iter, connect_cb);

         while(ec == boost::asio::error::would_block)

            {

            m_io.run_one();

            }

         if(ec)

            throw boost::system::system_error(ec);

         if(m_tcp.is_open() == false)

            throw System_Error("Connection to host " + hostname + " failed");

         }

      void write(const uint8_t buf[], size_t len) override

         {

         m_timer.expires_from_now(m_timeout);

         boost::system::error_code ec = boost::asio::error::would_block;

         m_tcp.async_send(boost::asio::buffer(buf, len),

                           [&ec](boost::system::error_code e, size_t) { ec = e; });

         while(ec == boost::asio::error::would_block) { m_io.run_one(); }

         if(ec)

            {

            throw boost::system::system_error(ec);

            }

         }

      size_t read(uint8_t buf[], size_t len) override

         {

         m_timer.expires_from_now(m_timeout);

         boost::system::error_code ec = boost::asio::error::would_block;

         size_t got = 0;

         m_tcp.async_read_some(boost::asio::buffer(buf, len),

                               [&](boost::system::error_code cb_ec, size_t cb_got) { ec = cb_ec; got = cb_got; });

         while(ec == boost::asio::error::would_block) { m_io.run_one(); }

         if(ec)

            {

            if(ec == boost::asio::error::eof)

               return 0;

            throw boost::system::system_error(ec); // Some other error.

            }

         return got;

         }

   private:

      void check_timeout()

         {

         if(m_tcp.is_open() && m_timer.expires_at() < std::chrono::system_clock::now())

            {

            boost::system::error_code err;

            m_tcp.close(err);

            }

         m_timer.async_wait(std::bind(&Asio_Socket::check_timeout, this));

         }

      const std::chrono::milliseconds m_timeout;

      boost::asio::io_service m_io;

      boost::asio::system_timer m_timer;

      boost::asio::ip::tcp::socket m_tcp;

   };

#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS) || defined(BOTAN_TARGET_OS_HAS_WINSOCK2)

class BSD_Socket final : public OS::Socket

   {

   private:

#if defined(BOTAN_TARGET_OS_HAS_WINSOCK2)

      typedef SOCKET socket_type;

      typedef int socket_op_ret_type;

      typedef int socklen_type;

      typedef int sendrecv_len_type;

      static socket_type invalid_socket() { return INVALID_SOCKET; }

      static void close_socket(socket_type s) { ::closesocket(s); }

      static std::string get_last_socket_error() { return std::to_string(::WSAGetLastError()); }

      static bool nonblocking_connect_in_progress()

         {

         return (::WSAGetLastError() == WSAEWOULDBLOCK);

         }

      static void set_nonblocking(socket_type s)

         {

         u_long nonblocking = 1;

         ::ioctlsocket(s, FIONBIO, &nonblocking);

         }

      static void socket_init()

         {

         WSAData wsa_data;

         WORD wsa_version = MAKEWORD(2, 2);

         if (::WSAStartup(wsa_version, &wsa_data) != 0)

            {

            throw System_Error("WSAStartup() failed", WSAGetLastError());

            }

         if (LOBYTE(wsa_data.wVersion) != 2 || HIBYTE(wsa_data.wVersion) != 2)

            {

            ::WSACleanup();

            throw System_Error("Could not find a usable version of Winsock.dll");

            }

         }

      static void socket_fini()

         {

         ::WSACleanup();

         }

#else

      typedef int socket_type;

      typedef ssize_t socket_op_ret_type;

      typedef socklen_t socklen_type;

      typedef size_t sendrecv_len_type;

      static socket_type invalid_socket() { return -1; }

      static void close_socket(socket_type s) { ::close(s); }

      static std::string get_last_socket_error() { return ::strerror(errno); }

      static bool nonblocking_connect_in_progress() { return (errno == EINPROGRESS); }

      static void set_nonblocking(socket_type s)

         {

         if(::fcntl(s, F_SETFL, O_NONBLOCK) < 0)

            throw System_Error("Setting socket to non-blocking state failed", errno);

         }

      static void socket_init() {}

      static void socket_fini() {}

#endif

   public:

      BSD_Socket(const std::string& hostname,

                 const std::string& service,

                 std::chrono::microseconds timeout) : m_timeout(timeout)

         {

         socket_init();

         m_socket = invalid_socket();

         addrinfo hints;

         clear_mem(&hints, 1);

         hints.ai_family = AF_UNSPEC;

         hints.ai_socktype = SOCK_STREAM;

         addrinfo* res;

         int rc = ::getaddrinfo(hostname.c_str(), service.c_str(), &hints, &res);

         if(rc != 0)

            {

            throw System_Error("Name resolution failed for " + hostname, rc);

            }

         for(addrinfo* rp = res; (m_socket == invalid_socket()) && (rp != nullptr); rp = rp->ai_next)

            {

            if(rp->ai_family != AF_INET && rp->ai_family != AF_INET6)

               continue;

            m_socket = ::socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);

            if(m_socket == invalid_socket())

               {

               // unsupported socket type?

               continue;

               }

            set_nonblocking(m_socket);

            int err = ::connect(m_socket, rp->ai_addr, static_cast<socklen_type>(rp->ai_addrlen));

            if(err == -1)

               {

               int active = 0;

               if(nonblocking_connect_in_progress())

                  {

                  struct timeval timeout_tv = make_timeout_tv();

                  fd_set write_set;

                  FD_ZERO(&write_set);

                  // Weirdly, Winsock uses a SOCKET type but wants FD_SET to get an int instead

                  FD_SET(static_cast<int>(m_socket), &write_set);

                  active = ::select(static_cast<int>(m_socket + 1), nullptr, &write_set, nullptr, &timeout_tv);

                  if(active)

                     {

                     int socket_error = 0;

                     socklen_t len = sizeof(socket_error);

                     if(::getsockopt(m_socket, SOL_SOCKET, SO_ERROR, reinterpret_cast<char*>(&socket_error), &len) < 0)

                        throw System_Error("Error calling getsockopt", errno);

                     if(socket_error != 0)

                        {

                        active = 0;

                        }

                     }

                  }

               if(active == 0)

                  {

                  close_socket(m_socket);

                  m_socket = invalid_socket();

                  continue;

                  }

               }

            }

         ::freeaddrinfo(res);

         if(m_socket == invalid_socket())

            {

            throw System_Error("Connecting to " + hostname +

                                " for service " + service + " failed", errno);

            }

         }

      ~BSD_Socket()

         {

         close_socket(m_socket);

         m_socket = invalid_socket();

         socket_fini();

         }

      void write(const uint8_t buf[], size_t len) override

         {

         fd_set write_set;

         FD_ZERO(&write_set);

         FD_SET(m_socket, &write_set);

         size_t sent_so_far = 0;

         while(sent_so_far != len)

            {

            struct timeval timeout = make_timeout_tv();

            int active = ::select(static_cast<int>(m_socket + 1), nullptr, &write_set, nullptr, &timeout);

            if(active == 0)

               throw System_Error("Timeout during socket write");

            const size_t left = len - sent_so_far;

            socket_op_ret_type sent = ::send(m_socket, cast_uint8_ptr_to_char(&buf[sent_so_far]), static_cast<sendrecv_len_type>(left), 0);

            if(sent < 0)

               throw System_Error("Socket write failed", errno);

            else

               sent_so_far += static_cast<size_t>(sent);

            }

         }

      size_t read(uint8_t buf[], size_t len) override

         {

         fd_set read_set;

         FD_ZERO(&read_set);

         FD_SET(m_socket, &read_set);

         struct timeval timeout = make_timeout_tv();

         int active = ::select(static_cast<int>(m_socket + 1), &read_set, nullptr, nullptr, &timeout);

         if(active == 0)

            throw System_Error("Timeout during socket read");

         socket_op_ret_type got = ::recv(m_socket, cast_uint8_ptr_to_char(buf), static_cast<sendrecv_len_type>(len), 0);

         if(got < 0)

            throw System_Error("Socket read failed", errno);

         return static_cast<size_t>(got);

         }

   private:

      struct timeval make_timeout_tv() const

         {

         struct timeval tv;

         tv.tv_sec = static_cast<decltype(timeval::tv_sec)>(m_timeout.count() / 1000000);

         tv.tv_usec = static_cast<decltype(timeval::tv_usec)>(m_timeout.count() % 1000000);;

         return tv;

         }

      const std::chrono::microseconds m_timeout;

      socket_type m_socket;

   };

#endif

}

std::unique_ptr<OS::Socket>

OS::open_socket(const std::string& hostname,

                const std::string& service,

                std::chrono::milliseconds timeout)

   {

#if defined(BOTAN_HAS_BOOST_ASIO)

   return std::unique_ptr<OS::Socket>(new Asio_Socket(hostname, service, timeout));

#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS) || defined(BOTAN_TARGET_OS_HAS_WINSOCK2)

   return std::unique_ptr<OS::Socket>(new BSD_Socket(hostname, service, timeout));

#else

   BOTAN_UNUSED(hostname);

   BOTAN_UNUSED(service);

   BOTAN_UNUSED(timeout);

   // No sockets for you

   return std::unique_ptr<Socket>();

#endif

   }

}