/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2018 Paul Sokolovsky
 * Copyright (c) 2014-2019 Damien P. George
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "py/mpconfig.h"

#if MICROPY_PY_SOCKET

#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifdef _WIN32
// To get inet_pton and inet_ntop.
#ifdef __MINGW32__
#ifdef _WIN32_WINNT
#undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0600
#endif
#include <winsock2.h>
#include <ws2tcpip.h>
#ifndef __MINGW32__
#pragma comment(lib, "Ws2_32.lib")
#endif
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <poll.h>
#endif
#include <errno.h>
#include <math.h>

#include "py/objtuple.h"
#include "py/objstr.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "py/builtin.h"
#include "py/mphal.h"
#include "py/mpthread.h"
#include "extmod/vfs.h"

#ifdef _WIN32
// Some extra info regarding the windows-specific code:
// - like CPython, most of the error codes raised as OSError will be the WSA error codes, not errno.
// - places where EAGAIN is turned into MP_ETIMEOUT are generally not needed On windows since the
//   socket calls already return WSAETIMEDOUT.
// - makefile() and poll functionality are not implemented.

typedef int sock_len_t;
typedef int socket_size_t;
typedef SOCKET socket_t;

// Just to make sure since we rely on this.
#if SOCKET_ERROR != -1
#error socket functions must return -1 for errors
#endif
#if NO_ERROR != 0
#error socket functions must return 0 for no errors
#endif

#define socket_errno WSAGetLastError()
#define socket_eintr WSAEINTR
#define read_socket(fd, buf, size) recv(fd, buf, size, 0)
#define write_socket(fd, buf, size) send(fd, buf, size, 0)
#define close_socket(fd) closesocket(fd)

void wsa_startup() {
    WSADATA wsaData;
    (void)WSAStartup(MAKEWORD(1, 1), &wsaData);
}

void wsa_cleanup() {
    (void)WSACleanup();
}

// Socket calls are syscalls but with WSA error codes, not errno.
#ifdef MP_HAL_RETRY_SYSCALL
#undef MP_HAL_RETRY_SYSCALL
#endif

#define MP_HAL_RETRY_SYSCALL(ret, syscall, raise) { \
        for (;;) { \
            MP_THREAD_GIL_EXIT(); \
            ret = syscall; \
            MP_THREAD_GIL_ENTER(); \
            if (ret == -1) { \
                int err = WSAGetLastError(); \
                if (err == WSAEINTR) { \
                    mp_handle_pending(true); \
                    continue; \
                } \
                raise; \
            } \
            break; \
        } \
}

// Get SO_RCVTIMEO or SO_SNDTIMEO values.
DWORD get_socket_timeout(socket_t sock, bool read_or_write) {
    MP_THREAD_GIL_EXIT();
    DWORD timeout = 0;
    int opt_len = sizeof(timeout);
    const int opt_name = read_or_write ? SO_RCVTIMEO : SO_SNDTIMEO;
    const int r = getsockopt(sock, SOL_SOCKET, opt_name, (char *)&timeout, &opt_len);
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(r, WSAGetLastError());
    return timeout;
}

// Perform select() call, raising timeout error if timed out.
void select_on_socket(socket_t sock, bool read_or_write, DWORD timeout) {
    fd_set fdset;
    FD_ZERO(&fdset);
    FD_SET(sock, &fdset);
    struct timeval tv;
    tv.tv_sec = timeout / 1000;
    tv.tv_usec = (timeout * 1000) % 1000;
    int r;
    fd_set *read_fd = read_or_write ? &fdset : NULL;
    fd_set *write_fd = read_or_write ? NULL : &fdset;
    // First argument is ignored: "The nfds parameter is included only for
    // compatibility with Berkeley sockets".
    MP_HAL_RETRY_SYSCALL(r, select(1, read_fd, write_fd, NULL, &tv), {
        // r < 0 is error, r == 0 is timeout, r > 0 = no timeout.
        RAISE_ERRNO(r, WSAGetLastError());
    });
    if (r == 0) {
        mp_raise_OSError(MP_ETIMEDOUT);
    }
}
#else
typedef socklen_t sock_len_t;
typedef int socket_t;
typedef ssize_t socket_size_t;

#define socket_errno errno
#define socket_eintr EINTR
#define read_socket read
#define write_socket write
#define close_socket close

#define initialize_socket_system() {}
#endif

/*
  The idea of this module is to implement reasonable minimum of
  socket-related functions to write typical clients and servers.
  It's then possible to make a Python-level module more (or fully)
  compatible with CPython "socket", e.g.:
  ---- socket.py ----
  from socket import *
  from socket_more_funcs import *
  from socket_more_funcs2 import *
  -------------------
  I.e. this module should stay lean, and more functions (if needed)
  should be add to separate modules (C or Python level).
 */

typedef struct _mp_obj_socket_t {
    mp_obj_base_t base;
    socket_t fd;
    bool blocking;
} mp_obj_socket_t;

const mp_obj_type_t mp_type_socket;

// Helper functions
static inline mp_obj_t mp_obj_from_sockaddr(const struct sockaddr *addr, sock_len_t len) {
    return mp_obj_new_bytes((const byte *)addr, len);
}

static mp_obj_socket_t *socket_new(socket_t fd) {
    mp_obj_socket_t *o = mp_obj_malloc(mp_obj_socket_t, &mp_type_socket);
    o->fd = fd;
    o->blocking = true;
    return o;
}


static void socket_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    (void)kind;
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    mp_printf(print, "<_socket %d>", self->fd);
}

static mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
    mp_obj_socket_t *o = MP_OBJ_TO_PTR(o_in);
    socket_size_t r;
    MP_HAL_RETRY_SYSCALL(r, read_socket(o->fd, buf, size), {
        // On blocking socket, we get EAGAIN in case SO_RCVTIMEO/SO_SNDTIMEO
        // timed out, and need to convert that to ETIMEDOUT.
        if (err == EAGAIN && o->blocking) {
            err = MP_ETIMEDOUT;
        }

        *errcode = err;
        return MP_STREAM_ERROR;
    });
    return (mp_uint_t)r;
}

static mp_uint_t socket_write(mp_obj_t o_in, const void *buf, mp_uint_t size, int *errcode) {
    mp_obj_socket_t *o = MP_OBJ_TO_PTR(o_in);
    socket_size_t r;
    MP_HAL_RETRY_SYSCALL(r, write_socket(o->fd, buf, size), {
        // On blocking socket, we get EAGAIN in case SO_RCVTIMEO/SO_SNDTIMEO
        // timed out, and need to convert that to ETIMEDOUT.
        if (err == EAGAIN && o->blocking) {
            err = MP_ETIMEDOUT;
        }

        *errcode = err;
        return MP_STREAM_ERROR;
    });
    return (mp_uint_t)r;
}

static mp_uint_t socket_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, int *errcode) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(o_in);
    (void)arg;
    switch (request) {
        case MP_STREAM_CLOSE:
            // There's a POSIX drama regarding return value of close in general,
            // and EINTR error in particular. See e.g.
            // http://lwn.net/Articles/576478/
            // http://austingroupbugs.net/view.php?id=529
            // The rationale MicroPython follows is that close() just releases
            // file descriptor. If you're interested to catch I/O errors before
            // closing fd, fsync() it.
            MP_THREAD_GIL_EXIT();
            close_socket(self->fd);
            MP_THREAD_GIL_ENTER();
            return 0;

        #ifndef _WIN32
        case MP_STREAM_GET_FILENO:
            return self->fd;

        #if MICROPY_PY_SELECT
        case MP_STREAM_POLL: {
            mp_uint_t ret = 0;
            uint8_t pollevents = 0;
            if (arg & MP_STREAM_POLL_RD) {
                pollevents |= POLLIN;
            }
            if (arg & MP_STREAM_POLL_WR) {
                pollevents |= POLLOUT;
            }
            struct pollfd pfd = { .fd = self->fd, .events = pollevents };
            if (poll(&pfd, 1, 0) > 0) {
                if (pfd.revents & POLLIN) {
                    ret |= MP_STREAM_POLL_RD;
                }
                if (pfd.revents & POLLOUT) {
                    ret |= MP_STREAM_POLL_WR;
                }
                if (pfd.revents & POLLERR) {
                    ret |= MP_STREAM_POLL_ERR;
                }
                if (pfd.revents & POLLHUP) {
                    ret |= MP_STREAM_POLL_HUP;
                }
                if (pfd.revents & POLLNVAL) {
                    ret |= MP_STREAM_POLL_NVAL;
                }
            }
            return ret;
        }
        #endif
        #endif

        default:
            *errcode = MP_EINVAL;
            return MP_STREAM_ERROR;
    }
}

#ifndef _WIN32
static mp_obj_t socket_fileno(mp_obj_t self_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    return MP_OBJ_NEW_SMALL_INT(self->fd);
}
static MP_DEFINE_CONST_FUN_OBJ_1(socket_fileno_obj, socket_fileno);
#endif

static mp_obj_t socket_connect(mp_obj_t self_in, mp_obj_t addr_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(addr_in, &bufinfo, MP_BUFFER_READ);

    // special case of PEP 475 to retry only if blocking so we can't use
    // MP_HAL_RETRY_SYSCALL() here
    for (;;) {
        #ifdef _WIN32
        // The connect() call has no timeout so implement it by first calling select().
        // In theory there's a race condition here between select() returning and connect()
        // being called, in practice doesn't seem worth fixing.
        const DWORD timeout = get_socket_timeout(self->fd, true);
        if (timeout > 0 && self->blocking) {
            select_on_socket(self->fd, true, timeout);
        }
        #endif
        MP_THREAD_GIL_EXIT();
        int r = connect(self->fd, (const struct sockaddr *)bufinfo.buf, bufinfo.len);
        MP_THREAD_GIL_ENTER();
        if (r == -1) {
            int err = socket_errno;
            if (self->blocking) {
                if (err == socket_eintr) {
                    mp_handle_pending(true);
                    continue;
                }
                // EINPROGRESS on a blocking socket means the operation timed out
                if (err == EINPROGRESS) {
                    err = MP_ETIMEDOUT;
                }
            }
            mp_raise_OSError(err);
        }
        return mp_const_none;
    }
}
static MP_DEFINE_CONST_FUN_OBJ_2(socket_connect_obj, socket_connect);

static mp_obj_t socket_bind(mp_obj_t self_in, mp_obj_t addr_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(addr_in, &bufinfo, MP_BUFFER_READ);
    MP_THREAD_GIL_EXIT();
    int r = bind(self->fd, (const struct sockaddr *)bufinfo.buf, bufinfo.len);
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(r, socket_errno);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_2(socket_bind_obj, socket_bind);

// method socket.listen([backlog])
static mp_obj_t socket_listen(size_t n_args, const mp_obj_t *args) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);

    int backlog = MICROPY_PY_SOCKET_LISTEN_BACKLOG_DEFAULT;
    if (n_args > 1) {
        backlog = (int)mp_obj_get_int(args[1]);
        backlog = (backlog < 0) ? 0 : backlog;
    }

    MP_THREAD_GIL_EXIT();
    int r = listen(self->fd, backlog);
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(r, socket_errno);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_listen_obj, 1, 2, socket_listen);

static mp_obj_t socket_accept(mp_obj_t self_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    // sockaddr_storage isn't stack-friendly (129 bytes or so)
    // struct sockaddr_storage addr;
    byte addr[32];
    sock_len_t addr_len = sizeof(addr);
    socket_t fd;
    #ifdef _WIN32
    // The accept() call has no timeout so manually implement it by first calling select().
    const DWORD timeout = get_socket_timeout(self->fd, true);
    if (timeout > 0 && self->blocking) {
        select_on_socket(self->fd, true, timeout);
    }
    // The accept() call returns a socket, not an int, so cannot use MP_HAL_RETRY_SYSCALL.
    for (;;) {
        fd = accept(self->fd, (struct sockaddr *)&addr, &addr_len);
        if (fd == INVALID_SOCKET) {
            const int err = WSAGetLastError();
            if (err == WSAEINTR) {
                mp_handle_pending(1);
                continue;
            }
            mp_raise_OSError(err);
        }
        break;
    }
    #else
    MP_HAL_RETRY_SYSCALL(fd, accept(self->fd, (struct sockaddr *)&addr, &addr_len), {
        // EAGAIN on a blocking socket means the operation timed out
        if (self->blocking && err == EAGAIN) {
            err = MP_ETIMEDOUT;
        }
        mp_raise_OSError(err);
    });
    #endif

    mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(2, NULL));
    t->items[0] = MP_OBJ_FROM_PTR(socket_new(fd));
    t->items[1] = mp_obj_new_bytearray(addr_len, &addr);

    return MP_OBJ_FROM_PTR(t);
}
static MP_DEFINE_CONST_FUN_OBJ_1(socket_accept_obj, socket_accept);

// Note: besides flag param, this differs from read() in that
// this does not swallow blocking errors (EAGAIN, EWOULDBLOCK) -
// these would be thrown as exceptions.
static mp_obj_t socket_recv(size_t n_args, const mp_obj_t *args) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    int sz = MP_OBJ_SMALL_INT_VALUE(args[1]);
    int flags = 0;

    if (n_args > 2) {
        flags = MP_OBJ_SMALL_INT_VALUE(args[2]);
    }

    byte *buf = m_new(byte, sz);
    socket_size_t out_sz;
    MP_HAL_RETRY_SYSCALL(out_sz, recv(self->fd, (char *)buf, sz, flags), mp_raise_OSError(err));
    mp_obj_t ret = mp_obj_new_str_of_type(&mp_type_bytes, buf, out_sz);
    m_del(char, buf, sz);
    return ret;
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_recv_obj, 2, 3, socket_recv);

static mp_obj_t socket_recvfrom(size_t n_args, const mp_obj_t *args) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    int sz = MP_OBJ_SMALL_INT_VALUE(args[1]);
    int flags = 0;

    if (n_args > 2) {
        flags = MP_OBJ_SMALL_INT_VALUE(args[2]);
    }

    struct sockaddr_storage addr;
    sock_len_t addr_len = sizeof(addr);

    byte *buf = m_new(byte, sz);
    socket_size_t out_sz;
    MP_HAL_RETRY_SYSCALL(out_sz, recvfrom(self->fd, (char *)buf, sz, flags, (struct sockaddr *)&addr, &addr_len),
        mp_raise_OSError(err));
    mp_obj_t buf_o = mp_obj_new_str_of_type(&mp_type_bytes, buf, out_sz);
    m_del(char, buf, sz);

    mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(2, NULL));
    t->items[0] = buf_o;
    t->items[1] = mp_obj_from_sockaddr((struct sockaddr *)&addr, addr_len);

    return MP_OBJ_FROM_PTR(t);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_recvfrom_obj, 2, 3, socket_recvfrom);

// Note: besides flag param, this differs from write() in that
// this does not swallow blocking errors (EAGAIN, EWOULDBLOCK) -
// these would be thrown as exceptions.
static mp_obj_t socket_send(size_t n_args, const mp_obj_t *args) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    int flags = 0;

    if (n_args > 2) {
        flags = MP_OBJ_SMALL_INT_VALUE(args[2]);
    }

    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
    socket_size_t out_sz;
    MP_HAL_RETRY_SYSCALL(out_sz, send(self->fd, bufinfo.buf, bufinfo.len, flags),
        mp_raise_OSError(err));
    return MP_OBJ_NEW_SMALL_INT(out_sz);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_send_obj, 2, 3, socket_send);

static mp_obj_t socket_sendto(size_t n_args, const mp_obj_t *args) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    int flags = 0;

    mp_obj_t dst_addr = args[2];
    if (n_args > 3) {
        flags = MP_OBJ_SMALL_INT_VALUE(args[2]);
        dst_addr = args[3];
    }

    mp_buffer_info_t bufinfo, addr_bi;
    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
    mp_get_buffer_raise(dst_addr, &addr_bi, MP_BUFFER_READ);
    socket_size_t out_sz;
    MP_HAL_RETRY_SYSCALL(out_sz, sendto(self->fd, bufinfo.buf, bufinfo.len, flags,
        (struct sockaddr *)addr_bi.buf, addr_bi.len), mp_raise_OSError(err));
    return MP_OBJ_NEW_SMALL_INT(out_sz);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_sendto_obj, 3, 4, socket_sendto);

static mp_obj_t socket_setsockopt(size_t n_args, const mp_obj_t *args) {
    (void)n_args; // always 4
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    int level = MP_OBJ_SMALL_INT_VALUE(args[1]);
    int option = mp_obj_get_int(args[2]);

    const void *optval;
    sock_len_t optlen;
    int val;
    if (mp_obj_is_int(args[3])) {
        val = mp_obj_int_get_truncated(args[3]);
        optval = &val;
        optlen = sizeof(val);
    } else {
        mp_buffer_info_t bufinfo;
        mp_get_buffer_raise(args[3], &bufinfo, MP_BUFFER_READ);
        optval = bufinfo.buf;
        optlen = bufinfo.len;
    }
    MP_THREAD_GIL_EXIT();
    int r = setsockopt(self->fd, level, option, optval, optlen);
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(r, socket_errno);
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_setsockopt_obj, 4, 4, socket_setsockopt);

static mp_obj_t socket_setblocking(mp_obj_t self_in, mp_obj_t flag_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    int val = mp_obj_is_true(flag_in);
    MP_THREAD_GIL_EXIT();
    #ifdef _WIN32
    u_long mode = val ? 0 : 1;
    // Called 'flags' but here it's just the return value.
    const int flags = ioctlsocket(self->fd, FIONBIO, &mode);
    #else
    int flags = fcntl(self->fd, F_GETFL, 0);
    if (flags == -1) {
        MP_THREAD_GIL_ENTER();
        RAISE_ERRNO(flags, socket_errno);
    }
    if (val) {
        flags &= ~O_NONBLOCK;
    } else {
        flags |= O_NONBLOCK;
    }
    flags = fcntl(self->fd, F_SETFL, flags);
    #endif
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(flags, socket_errno);
    self->blocking = val;
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_2(socket_setblocking_obj, socket_setblocking);

static mp_obj_t socket_settimeout(mp_obj_t self_in, mp_obj_t timeout_in) {
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(self_in);
    struct timeval tv = {0, };
    #ifdef _WIN32
    DWORD time_val = 0;
    const char *ptv = (const char *)&time_val;
    const int opt_len = sizeof(DWORD);
    #else
    struct timeval *ptv = &tv;
    const int opt_len = sizeof(struct timeval);
    #endif
    bool new_blocking = true;

    // Timeout of None means no timeout, which in POSIX is signified with 0 timeout,
    // and that's how 'tv' is initialized above
    if (timeout_in != mp_const_none) {
        #if MICROPY_PY_BUILTINS_FLOAT
        mp_float_t val = mp_obj_get_float(timeout_in);
        mp_float_t ipart;
        tv.tv_usec = (time_t)MICROPY_FLOAT_C_FUN(round)(MICROPY_FLOAT_C_FUN(modf)(val, &ipart) * MICROPY_FLOAT_CONST(1000000.));
        tv.tv_sec = (suseconds_t)ipart;
        #else
        tv.tv_sec = mp_obj_get_int(timeout_in);
        #endif
        #ifdef _WIN32
        time_val = tv.tv_usec / 1000 + tv.tv_sec * 1000;
        #endif

        // For SO_RCVTIMEO/SO_SNDTIMEO, zero timeout means infinity, but
        // for Python API it means non-blocking.
        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
            new_blocking = false;
        }
    }

    if (new_blocking) {
        int r;
        MP_THREAD_GIL_EXIT();
        r = setsockopt(self->fd, SOL_SOCKET, SO_RCVTIMEO, ptv, opt_len);
        if (r == -1) {
            MP_THREAD_GIL_ENTER();
            RAISE_ERRNO(r, socket_errno);
        }
        r = setsockopt(self->fd, SOL_SOCKET, SO_SNDTIMEO, ptv, opt_len);
        MP_THREAD_GIL_ENTER();
        RAISE_ERRNO(r, socket_errno);
    }

    if (self->blocking != new_blocking) {
        socket_setblocking(self_in, mp_obj_new_bool(new_blocking));
    }

    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_2(socket_settimeout_obj, socket_settimeout);

#ifndef _WIN32
static mp_obj_t socket_makefile(size_t n_args, const mp_obj_t *args) {
    // TODO: CPython explicitly says that closing returned object doesn't close
    // the original socket (Python2 at all says that fd is dup()ed). But we
    // save on the bloat.
    mp_obj_socket_t *self = MP_OBJ_TO_PTR(args[0]);
    mp_obj_t *new_args = alloca(n_args * sizeof(mp_obj_t));
    memcpy(new_args + 1, args + 1, (n_args - 1) * sizeof(mp_obj_t));
    new_args[0] = MP_OBJ_NEW_SMALL_INT(self->fd);
    return mp_vfs_open(n_args, new_args, (mp_map_t *)&mp_const_empty_map);
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(socket_makefile_obj, 1, 3, socket_makefile);
#endif

static mp_obj_t socket_make_new(const mp_obj_type_t *type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
    (void)type_in;
    (void)n_kw;

    int family = AF_INET;
    int type = SOCK_STREAM;
    int proto = 0;

    if (n_args > 0) {
        assert(mp_obj_is_small_int(args[0]));
        family = MP_OBJ_SMALL_INT_VALUE(args[0]);
        if (n_args > 1) {
            assert(mp_obj_is_small_int(args[1]));
            type = MP_OBJ_SMALL_INT_VALUE(args[1]);
            if (n_args > 2) {
                assert(mp_obj_is_small_int(args[2]));
                proto = MP_OBJ_SMALL_INT_VALUE(args[2]);
            }
        }
    }

    MP_THREAD_GIL_EXIT();
    socket_t fd = socket(family, type, proto);
    #ifdef _WIN32
    const int err = fd == INVALID_SOCKET ? -1 : 0;
    #else
    const int err = fd;
    #endif
    MP_THREAD_GIL_ENTER();
    RAISE_ERRNO(err, socket_errno);
    return MP_OBJ_FROM_PTR(socket_new(fd));
}

static const mp_rom_map_elem_t socket_locals_dict_table[] = {
    #ifndef _WIN32
    { MP_ROM_QSTR(MP_QSTR_fileno), MP_ROM_PTR(&socket_fileno_obj) },
    { MP_ROM_QSTR(MP_QSTR_makefile), MP_ROM_PTR(&socket_makefile_obj) },
    #endif
    { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
    { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
    { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
    { MP_ROM_QSTR(MP_QSTR_connect), MP_ROM_PTR(&socket_connect_obj) },
    { MP_ROM_QSTR(MP_QSTR_bind), MP_ROM_PTR(&socket_bind_obj) },
    { MP_ROM_QSTR(MP_QSTR_listen), MP_ROM_PTR(&socket_listen_obj) },
    { MP_ROM_QSTR(MP_QSTR_accept), MP_ROM_PTR(&socket_accept_obj) },
    { MP_ROM_QSTR(MP_QSTR_recv), MP_ROM_PTR(&socket_recv_obj) },
    { MP_ROM_QSTR(MP_QSTR_recvfrom), MP_ROM_PTR(&socket_recvfrom_obj) },
    { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&socket_send_obj) },
    { MP_ROM_QSTR(MP_QSTR_sendto), MP_ROM_PTR(&socket_sendto_obj) },
    { MP_ROM_QSTR(MP_QSTR_setsockopt), MP_ROM_PTR(&socket_setsockopt_obj) },
    { MP_ROM_QSTR(MP_QSTR_setblocking), MP_ROM_PTR(&socket_setblocking_obj) },
    { MP_ROM_QSTR(MP_QSTR_settimeout), MP_ROM_PTR(&socket_settimeout_obj) },
    { MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&mp_stream_close_obj) },
};

static MP_DEFINE_CONST_DICT(socket_locals_dict, socket_locals_dict_table);

static const mp_stream_p_t socket_stream_p = {
    .read = socket_read,
    .write = socket_write,
    .ioctl = socket_ioctl,
};

MP_DEFINE_CONST_OBJ_TYPE(
    mp_type_socket,
    MP_QSTR_socket,
    MP_TYPE_FLAG_NONE,
    make_new, socket_make_new,
    print, socket_print,
    protocol, &socket_stream_p,
    locals_dict, &socket_locals_dict
    );

#define BINADDR_MAX_LEN sizeof(struct in6_addr)
static mp_obj_t mod_socket_inet_pton(mp_obj_t family_in, mp_obj_t addr_in) {
    int family = mp_obj_get_int(family_in);
    byte binaddr[BINADDR_MAX_LEN];
    int r = inet_pton(family, mp_obj_str_get_str(addr_in), binaddr);
    RAISE_ERRNO(r, socket_errno);
    if (r == 0) {
        mp_raise_OSError(MP_EINVAL);
    }
    int binaddr_len = 0;
    switch (family) {
        case AF_INET:
            binaddr_len = sizeof(struct in_addr);
            break;
        case AF_INET6:
            binaddr_len = sizeof(struct in6_addr);
            break;
    }
    return mp_obj_new_bytes(binaddr, binaddr_len);
}
static MP_DEFINE_CONST_FUN_OBJ_2(mod_socket_inet_pton_obj, mod_socket_inet_pton);

static mp_obj_t mod_socket_inet_ntop(mp_obj_t family_in, mp_obj_t binaddr_in) {
    int family = mp_obj_get_int(family_in);
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(binaddr_in, &bufinfo, MP_BUFFER_READ);
    vstr_t vstr;
    vstr_init_len(&vstr, family == AF_INET ? INET_ADDRSTRLEN : INET6_ADDRSTRLEN);
    if (inet_ntop(family, bufinfo.buf, vstr.buf, vstr.len) == NULL) {
        mp_raise_OSError(socket_errno);
    }
    vstr.len = strlen(vstr.buf);
    return mp_obj_new_str_from_utf8_vstr(&vstr);
}
static MP_DEFINE_CONST_FUN_OBJ_2(mod_socket_inet_ntop_obj, mod_socket_inet_ntop);

static mp_obj_t mod_socket_getaddrinfo(size_t n_args, const mp_obj_t *args) {

    const char *host = mp_obj_str_get_str(args[0]);
    const char *serv = NULL;
    struct addrinfo hints;
    char buf[6];
    memset(&hints, 0, sizeof(hints));
    // getaddrinfo accepts port in string notation, so however
    // it may seem stupid, we need to convert int to str
    if (mp_obj_is_small_int(args[1])) {
        unsigned port = (unsigned short)MP_OBJ_SMALL_INT_VALUE(args[1]);
        snprintf(buf, sizeof(buf), "%u", port);
        serv = buf;
        hints.ai_flags = AI_NUMERICSERV;
        #ifdef __UCLIBC_MAJOR__
        #if __UCLIBC_MAJOR__ == 0 && (__UCLIBC_MINOR__ < 9 || (__UCLIBC_MINOR__ == 9 && __UCLIBC_SUBLEVEL__ <= 32))
// "warning" requires -Wno-cpp which is a relatively new gcc option, so we choose not to use it.
// #warning Working around uClibc bug with numeric service name
        // Older versions og uClibc have bugs when numeric ports in service
        // arg require also hints.ai_socktype (or hints.ai_protocol) != 0
        // This actually was fixed in 0.9.32.1, but uClibc doesn't allow to
        // test for that.
        // http://git.uclibc.org/uClibc/commit/libc/inet/getaddrinfo.c?id=bc3be18145e4d5
        // Note that this is crude workaround, precluding UDP socket addresses
        // to be returned. TODO: set only if not set by Python args.
        hints.ai_socktype = SOCK_STREAM;
        #endif
        #endif
    } else {
        serv = mp_obj_str_get_str(args[1]);
    }

    if (n_args > 2) {
        hints.ai_family = MP_OBJ_SMALL_INT_VALUE(args[2]);
        if (n_args > 3) {
            hints.ai_socktype = MP_OBJ_SMALL_INT_VALUE(args[3]);
            if (n_args > 4) {
                hints.ai_protocol = MP_OBJ_SMALL_INT_VALUE(args[4]);
                if (n_args > 5) {
                    hints.ai_flags = MP_OBJ_SMALL_INT_VALUE(args[5]);
                }
            }
        }
    }

    struct addrinfo *addr_list;
    MP_THREAD_GIL_EXIT();
    int res = getaddrinfo(host, serv, &hints, &addr_list);
    MP_THREAD_GIL_ENTER();

    if (res != 0) {
        // CPython: socket.gaierror
        mp_raise_msg_varg(&mp_type_OSError, MP_ERROR_TEXT("[addrinfo error %d]"), res);
    }
    assert(addr_list);

    mp_obj_t list = mp_obj_new_list(0, NULL);
    for (struct addrinfo *addr = addr_list; addr; addr = addr->ai_next) {
        mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(5, NULL));
        t->items[0] = MP_OBJ_NEW_SMALL_INT(addr->ai_family);
        t->items[1] = MP_OBJ_NEW_SMALL_INT(addr->ai_socktype);
        t->items[2] = MP_OBJ_NEW_SMALL_INT(addr->ai_protocol);
        // "canonname will be a string representing the canonical name of the host
        // if AI_CANONNAME is part of the flags argument; else canonname will be empty." ??
        if (addr->ai_canonname) {
            t->items[3] = MP_OBJ_NEW_QSTR(qstr_from_str(addr->ai_canonname));
        } else {
            t->items[3] = mp_const_none;
        }
        t->items[4] = mp_obj_new_bytearray(addr->ai_addrlen, addr->ai_addr);
        mp_obj_list_append(list, MP_OBJ_FROM_PTR(t));
    }
    freeaddrinfo(addr_list);
    return list;
}
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_socket_getaddrinfo_obj, 2, 6, mod_socket_getaddrinfo);

static mp_obj_t mod_socket_sockaddr(mp_obj_t sockaddr_in) {
    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(sockaddr_in, &bufinfo, MP_BUFFER_READ);
    switch (((struct sockaddr *)bufinfo.buf)->sa_family) {
        case AF_INET: {
            struct sockaddr_in *sa = (struct sockaddr_in *)bufinfo.buf;
            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(3, NULL));
            t->items[0] = MP_OBJ_NEW_SMALL_INT(AF_INET);
            t->items[1] = mp_obj_new_bytes((byte *)&sa->sin_addr, sizeof(sa->sin_addr));
            t->items[2] = MP_OBJ_NEW_SMALL_INT(ntohs(sa->sin_port));
            return MP_OBJ_FROM_PTR(t);
        }
        case AF_INET6: {
            struct sockaddr_in6 *sa = (struct sockaddr_in6 *)bufinfo.buf;
            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(5, NULL));
            t->items[0] = MP_OBJ_NEW_SMALL_INT(AF_INET6);
            t->items[1] = mp_obj_new_bytes((byte *)&sa->sin6_addr, sizeof(sa->sin6_addr));
            t->items[2] = MP_OBJ_NEW_SMALL_INT(ntohs(sa->sin6_port));
            t->items[3] = MP_OBJ_NEW_SMALL_INT(ntohl(sa->sin6_flowinfo));
            t->items[4] = MP_OBJ_NEW_SMALL_INT(ntohl(sa->sin6_scope_id));
            return MP_OBJ_FROM_PTR(t);
        }
        default: {
            struct sockaddr *sa = (struct sockaddr *)bufinfo.buf;
            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(2, NULL));
            t->items[0] = MP_OBJ_NEW_SMALL_INT(sa->sa_family);
            t->items[1] = mp_obj_new_bytes((byte *)sa->sa_data, bufinfo.len - offsetof(struct sockaddr, sa_data));
            return MP_OBJ_FROM_PTR(t);
        }
    }
    return mp_const_none;
}
static MP_DEFINE_CONST_FUN_OBJ_1(mod_socket_sockaddr_obj, mod_socket_sockaddr);

static const mp_rom_map_elem_t mp_module_socket_globals_table[] = {
    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_socket) },
    { MP_ROM_QSTR(MP_QSTR_socket), MP_ROM_PTR(&mp_type_socket) },
    { MP_ROM_QSTR(MP_QSTR_getaddrinfo), MP_ROM_PTR(&mod_socket_getaddrinfo_obj) },
    { MP_ROM_QSTR(MP_QSTR_inet_pton), MP_ROM_PTR(&mod_socket_inet_pton_obj) },
    { MP_ROM_QSTR(MP_QSTR_inet_ntop), MP_ROM_PTR(&mod_socket_inet_ntop_obj) },
    { MP_ROM_QSTR(MP_QSTR_sockaddr), MP_ROM_PTR(&mod_socket_sockaddr_obj) },

#define C(name) { MP_ROM_QSTR(MP_QSTR_##name), MP_ROM_INT(name) }
    C(AF_UNIX),
    C(AF_INET),
    C(AF_INET6),
    C(SOCK_STREAM),
    C(SOCK_DGRAM),
    C(SOCK_RAW),

    C(MSG_DONTROUTE),
    #ifndef _WIN32
    C(MSG_DONTWAIT),
    #endif

    C(SOL_SOCKET),
    C(SO_BROADCAST),
    C(SO_ERROR),
    C(SO_KEEPALIVE),
    C(SO_LINGER),
    C(SO_REUSEADDR),
#undef C
};

static MP_DEFINE_CONST_DICT(mp_module_socket_globals, mp_module_socket_globals_table);

const mp_obj_module_t mp_module_socket = {
    .base = { &mp_type_module },
    .globals = (mp_obj_dict_t *)&mp_module_socket_globals,
};

MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_socket, mp_module_socket);

#endif // MICROPY_PY_SOCKET