xref: /netbsd-src/external/gpl3/gcc/dist/libstdc++-v3/include/experimental/internet (revision d16b7486a53dcb8072b60ec6fcb4373a2d0c27b7)
1// <experimental/internet> -*- C++ -*-
2
3// Copyright (C) 2015-2022 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file experimental/internet
26 *  This is a TS C++ Library header.
27 *  @ingroup networking-ts
28 */
29
30#ifndef _GLIBCXX_EXPERIMENTAL_INTERNET
31#define _GLIBCXX_EXPERIMENTAL_INTERNET
32
33#pragma GCC system_header
34
35#if __cplusplus >= 201402L
36
37#include <experimental/netfwd>
38#include <experimental/io_context>
39#include <experimental/bits/net.h>
40#include <array>
41#include <forward_list>
42#include <sstream>
43#include <cstdint>
44#include <experimental/string_view>
45#ifdef _GLIBCXX_HAVE_UNISTD_H
46# include <unistd.h>
47#endif
48#ifdef _GLIBCXX_HAVE_SYS_SOCKET_H
49# include <sys/socket.h>	// AF_INET, AF_INET6, SOCK_DGRAM, SOCK_STREAM
50#endif
51#ifdef _GLIBCXX_HAVE_ARPA_INET_H
52# include <arpa/inet.h>		// inet_ntop
53#endif
54#ifdef _GLIBCXX_HAVE_NETINET_IN_H
55# include <netinet/in.h>	// IPPROTO_IP, IPPROTO_IPV6, in_addr, in6_addr
56#endif
57#ifdef _GLIBCXX_HAVE_NETINET_TCP_H
58# include <netinet/tcp.h>	// TCP_NODELAY
59#endif
60#ifdef _GLIBCXX_HAVE_NETDB_H
61# include <netdb.h>		// getaddrinfo etc.
62#endif
63
64#if defined _WIN32 && __has_include(<ws2tcpip.h>)
65# include <ws2tcpip.h>
66#endif
67
68namespace std _GLIBCXX_VISIBILITY(default)
69{
70_GLIBCXX_BEGIN_NAMESPACE_VERSION
71namespace experimental
72{
73namespace net
74{
75inline namespace v1
76{
77namespace ip
78{
79  /** @addtogroup networking-ts
80   *  @{
81   */
82
83  /** Error codes for resolver errors.
84   * @{
85   */
86
87  enum class resolver_errc : int {
88#ifdef _GLIBCXX_HAVE_NETDB_H
89    host_not_found = EAI_NONAME,
90    host_not_found_try_again = EAI_AGAIN,
91    service_not_found = EAI_SERVICE
92    // N.B. POSIX defines additional errors that have no enumerator here:
93    // EAI_BADFLAGS, EAI_FAIL, EAI_FAMILY, EAI_MEMORY, EAI_SOCKTYPE, EAI_SYSTEM
94    // Some C libraries define additional errors:
95    // EAI_BADHINTS, EAI_OVERFLOW, EAI_PROTOCOL
96    // Some C libraries define additional (obsolete?) errors:
97    // EAI_ADDRFAMILY, EAI_NODATA
98#endif
99  };
100
101  /// Error category for resolver errors.
102  inline const error_category& resolver_category() noexcept // TODO non-inline
103  {
104    struct __cat : error_category
105    {
106      const char* name() const noexcept { return "resolver"; }
107      std::string message(int __e) const {
108#ifdef _GLIBCXX_HAVE_NETDB_H
109	  return ::gai_strerror(__e);
110#else
111	  return "name resolution requires <netdb.h>";
112#endif
113      }
114      virtual void __message(int) { } // TODO dual ABI XXX
115    };
116    static __cat __c;
117    return __c;
118  }
119
120  inline error_code make_error_code(resolver_errc __e) noexcept
121  { return error_code(static_cast<int>(__e), resolver_category()); }
122
123  inline error_condition make_error_condition(resolver_errc __e) noexcept
124  { return error_condition(static_cast<int>(__e), resolver_category()); }
125
126  /// @cond undocumented
127  inline error_code
128  __make_resolver_error_code(int __ai_err,
129			     [[__maybe_unused__]] int __sys_err) noexcept
130  {
131#ifdef EAI_SYSTEM
132    if (__builtin_expect(__ai_err == EAI_SYSTEM, 0))
133      return error_code(__sys_err, std::generic_category());
134#endif
135    return error_code(__ai_err, resolver_category());
136  }
137  /// @endcond
138
139  /// @}
140
141  using port_type = uint_least16_t;	///< Type used for port numbers.
142  using scope_id_type = uint_least32_t;	///< Type used for IPv6 scope IDs.
143
144  /// Convenience alias for constraining allocators for strings.
145  template<typename _Alloc>
146    using __string_with
147      = enable_if_t<std::is_same<typename _Alloc::value_type, char>::value,
148		    std::basic_string<char, std::char_traits<char>, _Alloc>>;
149
150  constexpr errc
151  __unsupported_err() noexcept
152  {
153#if defined EAFNOSUPPORT
154    return std::errc::address_family_not_supported;
155#else
156    return std::errc::operation_not_supported;
157#endif
158  }
159
160  /** Tag indicating conversion between IPv4 and IPv4-mapped IPv6 addresses.
161   * @{
162   */
163
164  struct v4_mapped_t {};
165  constexpr v4_mapped_t v4_mapped;
166
167  /// @}
168
169  /// An IPv4 address.
170  class address_v4
171  {
172  public:
173    // types:
174    using uint_type = uint_least32_t;
175
176    struct bytes_type : array<unsigned char, 4>
177    {
178      template<typename... _Tp>
179	explicit constexpr
180	bytes_type(_Tp... __tp)
181	: array<unsigned char, 4>{{static_cast<unsigned char>(__tp)...}}
182	{
183#if UCHAR_MAX > 0xFF
184	  for (auto __b : *this)
185	    if (__b > 0xFF)
186	      __throw_out_of_range("invalid address_v4::bytes_type value");
187#endif
188	}
189    };
190
191    // constructors:
192    constexpr address_v4() noexcept : _M_addr(0) { }
193
194    constexpr address_v4(const address_v4& a) noexcept = default;
195
196    constexpr
197    address_v4(const bytes_type& __b)
198    : _M_addr((__b[0] << 24) | (__b[1] << 16) | (__b[2] << 8) | __b[3])
199    { }
200
201    explicit constexpr
202    address_v4(uint_type __val) : _M_addr(_S_hton_32(__val))
203    {
204#if UINT_LEAST32_MAX > 0xFFFFFFFF
205      if (__val > 0xFFFFFFFF)
206	__throw_out_of_range("invalid address_v4::uint_type value");
207#endif
208    }
209
210    // assignment:
211    address_v4& operator=(const address_v4& a) noexcept = default;
212
213    // members:
214    constexpr bool is_unspecified() const noexcept { return to_uint() == 0; }
215
216    constexpr bool
217    is_loopback() const noexcept
218    { return (to_uint() & 0xFF000000) == 0x7F000000; }
219
220    constexpr bool
221    is_multicast() const noexcept
222    { return (to_uint() & 0xF0000000) == 0xE0000000; }
223
224    constexpr bytes_type
225    to_bytes() const noexcept
226    {
227      return bytes_type{
228	  (_M_addr >> 24) & 0xFF,
229	  (_M_addr >> 16) & 0xFF,
230	  (_M_addr >> 8) & 0xFF,
231	  _M_addr & 0xFF
232      };
233    }
234
235    constexpr uint_type
236    to_uint() const noexcept { return _S_ntoh_32(_M_addr); }
237
238    template<typename _Allocator = allocator<char>>
239      __string_with<_Allocator>
240      to_string(const _Allocator& __a = _Allocator()) const
241      {
242#ifdef _GLIBCXX_HAVE_ARPA_INET_H
243	__string_with<_Allocator> __str(__a);
244	__str.resize(INET_ADDRSTRLEN);
245	if (inet_ntop(AF_INET, &_M_addr, &__str.front(), __str.size()))
246	  __str.erase(__str.find('\0'));
247	else
248	  __str.resize(0);
249	return __str;
250#else
251	std::__throw_system_error((int)__unsupported_err());
252#endif
253      }
254
255    // static members:
256    static constexpr address_v4 any() noexcept { return address_v4{}; }
257
258    static constexpr
259    address_v4 loopback() noexcept { return address_v4{0x7F000001}; }
260
261    static constexpr
262    address_v4 broadcast() noexcept { return address_v4{0xFFFFFFFF}; }
263
264  private:
265    template<typename _InternetProtocol>
266      friend class basic_endpoint;
267
268    friend address_v4 make_address_v4(const char*, error_code&) noexcept;
269
270#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
271    static constexpr uint16_t _S_hton_16(uint16_t __h) { return __h; }
272    static constexpr uint16_t _S_ntoh_16(uint16_t __n) { return __n; }
273    static constexpr uint32_t _S_hton_32(uint32_t __h) { return __h; }
274    static constexpr uint32_t _S_ntoh_32(uint32_t __n) { return __n; }
275#else
276    static constexpr uint16_t
277    _S_hton_16(uint16_t __h) { return __builtin_bswap16(__h); }
278
279    static constexpr uint16_t
280    _S_ntoh_16(uint16_t __n) { return __builtin_bswap16(__n); }
281
282    static constexpr uint32_t
283    _S_hton_32(uint32_t __h) { return __builtin_bswap32(__h); }
284
285    static constexpr uint32_t
286    _S_ntoh_32(uint32_t __n) { return __builtin_bswap32(__n); }
287#endif
288
289#ifdef _GLIBCXX_HAVE_ARPA_INET_H
290    in_addr_t _M_addr; // network byte order
291#else
292    uint32_t _M_addr;
293#endif
294  };
295
296  /// An IPv6 address.
297  class address_v6
298  {
299  public:
300    // types:
301    struct bytes_type : array<unsigned char, 16>
302    {
303      template<typename... _Tp>
304	explicit constexpr
305	bytes_type(_Tp... __t)
306	: array<unsigned char, 16>{{static_cast<unsigned char>(__t)...}}
307	{ }
308    };
309
310    // constructors:
311    constexpr address_v6() noexcept : _M_bytes(), _M_scope_id() { }
312
313    constexpr address_v6(const address_v6& __a) noexcept = default;
314
315    constexpr
316    address_v6(const bytes_type& __bytes, scope_id_type __scope = 0)
317    : _M_bytes(__bytes), _M_scope_id(__scope)
318    { }
319
320    // assignment:
321    address_v6& operator=(const address_v6& __a) noexcept = default;
322
323    // members:
324    void scope_id(scope_id_type __id) noexcept { _M_scope_id = __id; }
325
326    constexpr scope_id_type scope_id() const noexcept { return _M_scope_id; }
327
328    constexpr bool
329    is_unspecified() const noexcept
330    {
331      for (int __i = 0; __i < 16; ++__i)
332	if (_M_bytes[__i] != 0x00)
333	  return false;
334      return _M_scope_id == 0;
335    }
336
337    constexpr bool
338    is_loopback() const noexcept
339    {
340      for (int __i = 0; __i < 15; ++__i)
341	if (_M_bytes[__i] != 0x00)
342	  return false;
343      return _M_bytes[15] == 0x01 && _M_scope_id == 0;
344    }
345
346    constexpr bool
347    is_multicast() const noexcept { return _M_bytes[0] == 0xFF; }
348
349    constexpr bool
350    is_link_local() const noexcept
351    { return _M_bytes[0] == 0xFE && (_M_bytes[1] & 0xC0) == 0x80; }
352
353    constexpr bool
354    is_site_local() const noexcept
355    { return _M_bytes[0] == 0xFE && (_M_bytes[1] & 0xC0) == 0xC0; }
356
357    constexpr bool
358    is_v4_mapped() const noexcept
359    {
360      const bytes_type& __b = _M_bytes;
361      return __b[0] == 0 && __b[1] == 0 && __b[ 2] == 0    && __b[ 3] == 0
362	  && __b[4] == 0 && __b[5] == 0 && __b[ 6] == 0    && __b[ 7] == 0
363	  && __b[8] == 0 && __b[9] == 0 && __b[10] == 0xFF && __b[11] == 0xFF;
364    }
365
366    constexpr bool
367    is_multicast_node_local() const noexcept
368    { return is_multicast() && (_M_bytes[1] & 0x0F) == 0x01; }
369
370    constexpr bool
371    is_multicast_link_local() const noexcept
372    { return is_multicast() && (_M_bytes[1] & 0x0F) == 0x02; }
373
374    constexpr bool
375    is_multicast_site_local() const noexcept
376    { return is_multicast() && (_M_bytes[1] & 0x0F) == 0x05; }
377
378    constexpr bool
379    is_multicast_org_local() const noexcept
380    { return is_multicast() && (_M_bytes[1] & 0x0F) == 0x08; }
381
382    constexpr bool
383    is_multicast_global() const noexcept
384    { return is_multicast() && (_M_bytes[1] & 0x0F) == 0x0b; }
385
386    constexpr bytes_type to_bytes() const noexcept { return _M_bytes; }
387
388    template<typename _Allocator = allocator<char>>
389      __string_with<_Allocator>
390      to_string(const _Allocator& __a = _Allocator()) const
391      {
392#ifdef _GLIBCXX_HAVE_ARPA_INET_H
393	__string_with<_Allocator> __str(__a);
394	__str.resize(INET6_ADDRSTRLEN + (_M_scope_id ? 11 : 0));
395	char* const __p = &__str.front();
396	if (inet_ntop(AF_INET6, &_M_bytes, __p, __str.size()))
397	  {
398	    auto __end = __str.find('\0');
399	    if (unsigned long __scope = _M_scope_id)
400	      {
401		__end +=
402#if _GLIBCXX_USE_C99_STDIO
403		  __builtin_snprintf(__p + __end, __str.size() - __end,
404				     "%%%lu", __scope);
405#else
406		  __builtin_sprintf(__p + __end, "%%%lu", __scope);
407#endif
408	      }
409	    __str.erase(__end);
410	  }
411	else
412	  __str.resize(0);
413	return __str;
414#else
415	std::__throw_system_error((int)__unsupported_err());
416#endif
417      }
418
419    // static members:
420
421    static constexpr address_v6
422    any() noexcept
423    {
424      return {};
425    }
426
427    static constexpr address_v6
428    loopback() noexcept
429    {
430      return {bytes_type{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}};
431    }
432
433  private:
434    template<typename _InternetProtocol>
435      friend class basic_endpoint;
436
437    friend constexpr bool
438    operator==(const address_v6&, const address_v6&) noexcept;
439
440    friend constexpr bool
441    operator< (const address_v6&, const address_v6&) noexcept;
442
443    bytes_type _M_bytes;
444    scope_id_type _M_scope_id;
445  };
446
447  /// Exception type thrown on misuse of IPv4 addresses as IPv6 or vice versa.
448  class bad_address_cast : public bad_cast
449  {
450  public:
451    bad_address_cast() { }
452
453    const char* what() const noexcept { return "bad address cast"; }
454  };
455
456  /// An IPv4 or IPv6 address.
457  class address
458  {
459  public:
460    // constructors:
461    constexpr address() noexcept : _M_v4(), _M_is_v4(true) { }
462
463#if __cpp_constexpr_dynamic_alloc
464    constexpr
465#endif
466    address(const address& __a) noexcept : _M_uninit(), _M_is_v4(__a._M_is_v4)
467    {
468      if (_M_is_v4)
469	std::_Construct(std::addressof(_M_v4), __a.to_v4());
470      else
471	std::_Construct(std::addressof(_M_v6), __a.to_v6());
472    }
473
474    constexpr
475    address(const address_v4& __a) noexcept : _M_v4(__a), _M_is_v4(true) { }
476
477    constexpr
478    address(const address_v6& __a) noexcept : _M_v6(__a), _M_is_v4(false) { }
479
480    // assignment:
481    address&
482    operator=(const address& __a) noexcept
483    {
484      if (__a._M_is_v4)
485	*this = __a.to_v4();
486      else
487	*this = __a.to_v6();
488      return *this;
489    }
490
491    address&
492    operator=(const address_v4& __a) noexcept
493    {
494      std::_Construct(std::addressof(_M_v4), __a);
495      _M_is_v4 = true;
496      return *this;
497    }
498
499    address&
500    operator=(const address_v6& __a) noexcept
501    {
502      std::_Construct(std::addressof(_M_v6), __a);
503      _M_is_v4 = false;
504      return *this;
505    }
506
507    // members:
508
509    constexpr bool is_v4() const noexcept { return _M_is_v4; }
510    constexpr bool is_v6() const noexcept { return !_M_is_v4; }
511
512    constexpr address_v4
513    to_v4() const
514    {
515      if (!is_v4())
516	_GLIBCXX_THROW_OR_ABORT(bad_address_cast());
517      return _M_v4;
518    }
519
520    constexpr address_v6
521    to_v6() const
522    {
523      if (!is_v6())
524	_GLIBCXX_THROW_OR_ABORT(bad_address_cast());
525      return _M_v6;
526    }
527
528    constexpr bool
529    is_unspecified() const noexcept
530    { return _M_is_v4 ? _M_v4.is_unspecified() : _M_v6.is_unspecified(); }
531
532    constexpr bool
533    is_loopback() const noexcept
534    { return _M_is_v4 ? _M_v4.is_loopback() : _M_v6.is_loopback(); }
535
536    constexpr bool
537    is_multicast() const noexcept
538    { return _M_is_v4 ? _M_v4.is_multicast() : _M_v6.is_multicast(); }
539
540    template<typename _Allocator = allocator<char>>
541      __string_with<_Allocator>
542      to_string(const _Allocator& __a = _Allocator()) const
543      {
544	if (_M_is_v4)
545	  return to_v4().to_string(__a);
546	return to_v6().to_string(__a);
547      }
548
549  private:
550    template<typename _InternetProtocol>
551      friend class basic_endpoint;
552
553    friend constexpr bool
554    operator==(const address&, const address&) noexcept;
555
556    friend constexpr bool
557    operator<(const address&, const address&) noexcept;
558
559    union {
560      address_v4 _M_v4;
561      address_v6 _M_v6;
562      bool	 _M_uninit;
563    };
564    bool _M_is_v4;
565  };
566
567  /** ip::address_v4 comparisons
568   * @{
569   */
570
571  constexpr bool
572  operator==(const address_v4& __a, const address_v4& __b) noexcept
573  { return __a.to_uint() == __b.to_uint(); }
574
575  constexpr bool
576  operator!=(const address_v4& __a, const address_v4& __b) noexcept
577  { return !(__a == __b); }
578
579  constexpr bool
580  operator< (const address_v4& __a, const address_v4& __b) noexcept
581  { return __a.to_uint() < __b.to_uint(); }
582
583  constexpr bool
584  operator> (const address_v4& __a, const address_v4& __b) noexcept
585  { return __b < __a; }
586
587  constexpr bool
588  operator<=(const address_v4& __a, const address_v4& __b) noexcept
589  { return !(__b < __a); }
590
591  constexpr bool
592  operator>=(const address_v4& __a, const address_v4& __b) noexcept
593  { return !(__a < __b); }
594
595  /// @}
596
597  /** ip::address_v6 comparisons
598   * @{
599   */
600
601  constexpr bool
602  operator==(const address_v6& __a, const address_v6& __b) noexcept
603  {
604    const auto& __aa = __a._M_bytes;
605    const auto& __bb = __b._M_bytes;
606    int __i = 0;
607    for (; __i < 16 && __aa[__i] == __bb[__i]; ++__i)
608      ;
609    return __i == 16 ? __a.scope_id() == __b.scope_id() : false;
610  }
611
612  constexpr bool
613  operator!=(const address_v6& __a, const address_v6& __b) noexcept
614  { return !(__a == __b); }
615
616  constexpr bool
617  operator< (const address_v6& __a, const address_v6& __b) noexcept
618  {
619    const auto& __aa = __a._M_bytes;
620    const auto& __bb = __b._M_bytes;
621    int __i = 0;
622    for (; __i < 16 && __aa[__i] == __bb[__i]; ++__i)
623      ;
624    return __i == 16 ? __a.scope_id() < __b.scope_id() : __aa[__i] < __bb[__i];
625  }
626
627  constexpr bool
628  operator> (const address_v6& __a, const address_v6& __b) noexcept
629  { return __b < __a; }
630
631  constexpr bool
632  operator<=(const address_v6& __a, const address_v6& __b) noexcept
633  { return !(__b < __a); }
634
635  constexpr bool
636  operator>=(const address_v6& __a, const address_v6& __b) noexcept
637  { return !(__a < __b); }
638
639  /// @}
640
641  /** ip::address comparisons
642   * @{
643   */
644
645  constexpr bool
646  operator==(const address& __a, const address& __b) noexcept
647  {
648    if (__a.is_v4())
649      return __b.is_v4() ? __a._M_v4 == __b._M_v4 : false;
650    return __b.is_v4() ? false : __a._M_v6 == __b._M_v6;
651  }
652
653  constexpr bool
654  operator!=(const address& __a, const address& __b) noexcept
655  { return !(__a == __b); }
656
657  constexpr bool
658  operator< (const address& __a, const address& __b) noexcept
659  {
660    if (__a.is_v4())
661      return __b.is_v4() ? __a._M_v4 < __b._M_v4 : true;
662    return __b.is_v4() ? false : __a._M_v6 < __b._M_v6;
663  }
664
665  constexpr bool
666  operator> (const address& __a, const address& __b) noexcept
667  { return __b < __a; }
668
669  constexpr bool
670  operator<=(const address& __a, const address& __b) noexcept
671  { return !(__b < __a); }
672
673  constexpr bool
674  operator>=(const address& __a, const address& __b) noexcept
675  { return !(__a < __b); }
676
677  /// @}
678
679  /** ip::address_v4 creation
680   * @{
681   */
682
683  constexpr address_v4
684  make_address_v4(const address_v4::bytes_type& __b)
685  { return address_v4{__b}; }
686
687  constexpr address_v4
688  make_address_v4(address_v4::uint_type __val)
689  { return address_v4{__val}; }
690
691  constexpr address_v4
692  make_address_v4(v4_mapped_t, const address_v6& __a)
693  {
694    if (!__a.is_v4_mapped())
695      _GLIBCXX_THROW_OR_ABORT(bad_address_cast());
696
697    const auto __v6b = __a.to_bytes();
698    return address_v4::bytes_type(__v6b[12], __v6b[13], __v6b[14], __v6b[15]);
699  }
700
701  inline address_v4
702  make_address_v4(const char* __str, error_code& __ec) noexcept
703  {
704#ifdef _GLIBCXX_HAVE_ARPA_INET_H
705    address_v4 __a;
706    const int __res = ::inet_pton(AF_INET, __str, &__a._M_addr);
707    if (__res == 1)
708      {
709	__ec.clear();
710	return __a;
711      }
712    if (__res == 0)
713      __ec = std::make_error_code(std::errc::invalid_argument);
714    else
715      __ec.assign(errno, generic_category());
716#else
717    __ec = std::make_error_code(__unsupported_err());
718#endif
719    return {};
720  }
721
722  inline address_v4
723  make_address_v4(const char* __str)
724  { return make_address_v4(__str, __throw_on_error{"make_address_v4"}); }
725
726  inline address_v4
727  make_address_v4(const string& __str, error_code& __ec) noexcept
728  { return make_address_v4(__str.c_str(), __ec); }
729
730  inline address_v4
731  make_address_v4(const string& __str)
732  { return make_address_v4(__str.c_str()); }
733
734  inline address_v4
735  make_address_v4(string_view __str, error_code& __ec) noexcept
736  {
737    char __buf[16]; // INET_ADDRSTRLEN isn't defined on Windows
738    auto __len = __str.copy(__buf, sizeof(__buf));
739    if (__len == sizeof(__buf))
740      {
741	__ec = std::make_error_code(std::errc::invalid_argument);
742	return {};
743      }
744    __ec.clear();
745    __buf[__len] = '\0';
746    return make_address_v4(__buf, __ec);
747  }
748
749  inline address_v4
750  make_address_v4(string_view __str)
751  { return make_address_v4(__str, __throw_on_error{"make_address_v4"}); }
752
753  /// @}
754
755  /** ip::address_v6 creation
756   * @{
757   */
758
759  constexpr address_v6
760  make_address_v6(const address_v6::bytes_type& __b, scope_id_type __scope = 0)
761  { return address_v6{__b, __scope}; }
762
763  constexpr address_v6
764  make_address_v6(v4_mapped_t, const address_v4& __a) noexcept
765  {
766    const address_v4::bytes_type __v4b = __a.to_bytes();
767    address_v6::bytes_type __v6b(0, 0, 0, 0, 0, 0, 0, 0,
768				 0, 0, 0xFF, 0xFF,
769				 __v4b[0], __v4b[1], __v4b[2], __v4b[3]);
770    return address_v6(__v6b);
771  }
772
773  inline address_v6
774  __make_address_v6(const char* __addr, const char* __scope, error_code& __ec)
775  {
776#ifdef _GLIBCXX_HAVE_ARPA_INET_H
777    address_v6::bytes_type __b;
778    const int __res = ::inet_pton(AF_INET6, __addr, __b.data());
779    if (__res == 1)
780      {
781	__ec.clear();
782	if (!__scope)
783	  {
784	    return { __b };
785	  }
786
787	char* __eptr;
788	unsigned long __val = std::strtoul(__scope, &__eptr, 10);
789	if (__eptr != __scope && !*__eptr
790	    && __val <= numeric_limits<scope_id_type>::max())
791	  {
792	    return { __b, static_cast<scope_id_type>(__val) };
793	  }
794	__ec = std::make_error_code(std::errc::invalid_argument);
795      }
796    else if (__res == 0)
797      __ec = std::make_error_code(std::errc::invalid_argument);
798    else
799      __ec.assign(errno, generic_category());
800#else
801    __ec = std::make_error_code(__unsupported_err());
802#endif
803    return {};
804  }
805
806  inline address_v6
807  make_address_v6(const char* __str, error_code& __ec) noexcept
808  {
809    auto __p = __builtin_strchr(__str, '%');
810    if (__p == nullptr)
811      return __make_address_v6(__str, nullptr, __ec);
812    char __buf[64];
813    char* __out = __buf;
814    bool __skip_leading_zero = true;
815    while (__str < __p && __out < std::end(__buf))
816      {
817	if (!__skip_leading_zero || *__str != '0')
818	  {
819	    if (*__str == ':' || *__str == '.')
820	      __skip_leading_zero = true;
821	    else
822	      __skip_leading_zero = false;
823	    *__out = *__str;
824	  }
825	__str++;
826      }
827    if (__out == std::end(__buf))
828      {
829	__ec = std::make_error_code(std::errc::invalid_argument);
830	return {};
831      }
832    else
833      {
834	*__out = '\0';
835	return __make_address_v6(__buf, __p + 1, __ec);
836      }
837  }
838
839  inline address_v6
840  make_address_v6(const char* __str)
841  { return make_address_v6(__str, __throw_on_error{"make_address_v6"}); }
842
843  inline address_v6
844  make_address_v6(const string& __str, error_code& __ec) noexcept
845  {
846    auto __pos = __str.find('%');
847    if (__pos == string::npos)
848      return __make_address_v6(__str.c_str(), nullptr, __ec);
849    char __buf[64];
850    char* __out = __buf;
851    bool __skip_leading_zero = true;
852    size_t __n = 0;
853    while (__n < __pos && __out < std::end(__buf))
854      {
855	if (!__skip_leading_zero || __str[__n] != '0')
856	  {
857	    if (__str[__n] == ':' || __str[__n] == '.')
858	      __skip_leading_zero = true;
859	    else
860	      __skip_leading_zero = false;
861	    *__out = __str[__n];
862	  }
863	__n++;
864      }
865    if (__out == std::end(__buf))
866      {
867	__ec = std::make_error_code(std::errc::invalid_argument);
868	return {};
869      }
870    else
871      {
872	*__out = '\0';
873	return __make_address_v6(__buf, __str.c_str() + __pos + 1, __ec);
874      }
875  }
876
877  inline address_v6
878  make_address_v6(const string& __str)
879  { return make_address_v6(__str, __throw_on_error{"make_address_v6"}); }
880
881  inline address_v6
882  make_address_v6(string_view __str, error_code& __ec) noexcept
883  {
884    char __buf[64];
885    char* __out = __buf;
886    char* __scope = nullptr;
887    bool __skip_leading_zero = true;
888    size_t __n = 0;
889    while (__n < __str.length() && __out < std::end(__buf))
890      {
891	if (__str[__n] == '%')
892	  {
893	    if (__scope)
894	      __out = std::end(__buf);
895	    else
896	      {
897		*__out = '\0';
898		__scope = ++__out;
899		__skip_leading_zero = true;
900	      }
901	  }
902	else if (!__skip_leading_zero || __str[__n] != '0')
903	  {
904	    if (__str[__n] == ':' || __str[__n] == '.')
905	      __skip_leading_zero = true;
906	    else
907	      __skip_leading_zero = false;
908	    *__out = __str[__n];
909	    __out++;
910	  }
911	__n++;
912      }
913    if (__out == std::end(__buf))
914      {
915	__ec = std::make_error_code(std::errc::invalid_argument);
916	return {};
917      }
918    else
919      {
920	*__out = '\0';
921	return __make_address_v6(__buf, __scope, __ec);
922      }
923  }
924
925  inline address_v6
926  make_address_v6(string_view __str)
927  { return make_address_v6(__str, __throw_on_error{"make_address_v6"}); }
928
929  /// @}
930
931  /** ip::address creation
932   * @{
933   */
934
935  inline address
936  make_address(const char* __str, error_code& __ec) noexcept
937  {
938    address __a;
939    address_v6 __v6a = make_address_v6(__str, __ec);
940    if (!__ec)
941      __a = __v6a;
942    else
943    {
944      address_v4 __v4a = make_address_v4(__str, __ec);
945      if (!__ec)
946	__a = __v4a;
947    }
948    return __a;
949  }
950
951  inline address
952  make_address(const char* __str)
953  { return make_address(__str, __throw_on_error{"make_address"}); }
954
955  inline address
956  make_address(const string& __str, error_code& __ec) noexcept; // TODO
957
958  inline address
959  make_address(const string& __str)
960  { return make_address(__str, __throw_on_error{"make_address"}); }
961
962  inline address
963  make_address(string_view __str, error_code& __ec) noexcept
964  {
965    if (__str.rfind('\0') != string_view::npos)
966      return make_address(__str.data(), __ec);
967    return make_address(__str.to_string(), __ec); // TODO don't allocate
968  }
969
970  inline address
971  make_address(string_view __str)
972  { return make_address(__str, __throw_on_error{"make_address"}); }
973
974  /// @}
975
976  /// ip::address I/O
977  template<typename _CharT, typename _Traits>
978    inline basic_ostream<_CharT, _Traits>&
979    operator<<(basic_ostream<_CharT, _Traits>& __os, const address& __a)
980    { return __os << __a.to_string(); }
981
982  /// ip::address_v4 I/O
983  template<typename _CharT, typename _Traits>
984    inline basic_ostream<_CharT, _Traits>&
985    operator<<(basic_ostream<_CharT, _Traits>& __os, const address_v4& __a)
986    { return __os << __a.to_string(); }
987
988  /// ip::address_v6 I/O
989  template<typename _CharT, typename _Traits>
990    inline basic_ostream<_CharT, _Traits>&
991    operator<<(basic_ostream<_CharT, _Traits>& __os, const address_v6& __a)
992    { return __os << __a.to_string(); }
993
994  template<typename> class basic_address_iterator; // not defined
995
996  template<> class basic_address_iterator<address_v4>
997  {
998  public:
999    // types:
1000    using value_type = address_v4;
1001    using difference_type = ptrdiff_t;
1002    using pointer = const address_v4*;
1003    using reference = const address_v4&;
1004    using iterator_category = input_iterator_tag;
1005
1006    // constructors:
1007    basic_address_iterator(const address_v4& __a) noexcept
1008    : _M_address(__a) { }
1009
1010    // members:
1011    reference operator*() const noexcept { return _M_address; }
1012    pointer operator->() const noexcept { return &_M_address; }
1013
1014    basic_address_iterator&
1015    operator++() noexcept
1016    {
1017      _M_address = value_type(_M_address.to_uint() + 1);
1018      return *this;
1019    }
1020
1021    basic_address_iterator operator++(int) noexcept
1022    {
1023      auto __tmp = *this;
1024      ++*this;
1025      return __tmp;
1026    }
1027
1028    basic_address_iterator& operator--() noexcept
1029    {
1030      _M_address = value_type(_M_address.to_uint() - 1);
1031      return *this;
1032    }
1033
1034    basic_address_iterator
1035    operator--(int) noexcept
1036    {
1037      auto __tmp = *this;
1038      --*this;
1039      return __tmp;
1040    }
1041
1042    bool
1043    operator==(const basic_address_iterator& __rhs) const noexcept
1044    { return _M_address == __rhs._M_address; }
1045
1046    bool
1047    operator!=(const basic_address_iterator& __rhs) const noexcept
1048    { return _M_address != __rhs._M_address; }
1049
1050  private:
1051    address_v4 _M_address;
1052  };
1053
1054  using address_v4_iterator = basic_address_iterator<address_v4>;
1055
1056  template<> class basic_address_iterator<address_v6>
1057  {
1058  public:
1059    // types:
1060    using value_type = address_v6;
1061    using difference_type = ptrdiff_t;
1062    using pointer = const address_v6*;
1063    using reference = const address_v6&;
1064    using iterator_category = input_iterator_tag;
1065
1066    // constructors:
1067    basic_address_iterator(const address_v6& __a) noexcept
1068    : _M_address(__a) { }
1069
1070    // members:
1071    reference operator*() const noexcept { return _M_address; }
1072    pointer operator->() const noexcept { return &_M_address; }
1073
1074    basic_address_iterator&
1075    operator++() noexcept; // TODO
1076
1077    basic_address_iterator
1078    operator++(int) noexcept
1079    {
1080      auto __tmp = *this;
1081      ++*this;
1082      return __tmp;
1083    }
1084
1085    basic_address_iterator&
1086    operator--() noexcept; // TODO
1087
1088    basic_address_iterator
1089    operator--(int) noexcept
1090    {
1091      auto __tmp = *this;
1092      --*this;
1093      return __tmp;
1094    }
1095
1096    bool
1097    operator==(const basic_address_iterator& __rhs) const noexcept
1098    { return _M_address == __rhs._M_address; }
1099
1100    bool
1101    operator!=(const basic_address_iterator& __rhs) const noexcept
1102    { return _M_address != __rhs._M_address; }
1103
1104  private:
1105    address_v6 _M_address;
1106  };
1107
1108  using address_v6_iterator = basic_address_iterator<address_v6>;
1109
1110  template<typename> class basic_address_range; // not defined
1111
1112  /** An IPv6 address range.
1113   * @{
1114   */
1115
1116  template<> class basic_address_range<address_v4>
1117  {
1118  public:
1119    // types:
1120
1121    using iterator = basic_address_iterator<address_v4>;
1122
1123    // constructors:
1124
1125    basic_address_range() noexcept : _M_begin({}), _M_end({}) { }
1126
1127    basic_address_range(const address_v4& __first,
1128                        const address_v4& __last) noexcept
1129    : _M_begin(__first), _M_end(__last) { }
1130
1131    // members:
1132
1133    iterator begin() const noexcept { return _M_begin; }
1134    iterator end() const noexcept { return _M_end; }
1135    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_begin == _M_end; }
1136
1137    size_t
1138    size() const noexcept { return _M_end->to_uint() - _M_begin->to_uint(); }
1139
1140    iterator
1141    find(const address_v4& __addr) const noexcept
1142    {
1143      if (*_M_begin <= __addr && __addr < *_M_end)
1144	return iterator{__addr};
1145      return end();
1146    }
1147
1148  private:
1149    iterator _M_begin;
1150    iterator _M_end;
1151  };
1152
1153  using address_v4_range = basic_address_range<address_v4>;
1154
1155  /// @}
1156
1157  /** An IPv6 address range.
1158   * @{
1159   */
1160
1161  template<> class basic_address_range<address_v6>
1162  {
1163  public:
1164    // types:
1165
1166    using iterator = basic_address_iterator<address_v6>;
1167
1168    // constructors:
1169
1170    basic_address_range() noexcept : _M_begin({}), _M_end({}) { }
1171    basic_address_range(const address_v6& __first,
1172                        const address_v6& __last) noexcept
1173    : _M_begin(__first), _M_end(__last) { }
1174
1175    // members:
1176
1177    iterator begin() const noexcept { return _M_begin; }
1178    iterator end() const noexcept { return _M_end; }
1179    _GLIBCXX_NODISCARD bool empty() const noexcept { return _M_begin == _M_end; }
1180
1181    iterator
1182    find(const address_v6& __addr) const noexcept
1183    {
1184      if (*_M_begin <= __addr && __addr < *_M_end)
1185	return iterator{__addr};
1186      return end();
1187    }
1188
1189  private:
1190    iterator _M_begin;
1191    iterator _M_end;
1192  };
1193
1194  using address_v6_range = basic_address_range<address_v6>;
1195
1196  /// @}
1197
1198  bool
1199  operator==(const network_v4& __a, const network_v4& __b) noexcept;
1200
1201  bool
1202  operator==(const network_v6& __a, const network_v6& __b) noexcept;
1203
1204
1205  /// An IPv4 network address.
1206  class network_v4
1207  {
1208  public:
1209    // constructors:
1210    constexpr network_v4() noexcept : _M_addr(), _M_prefix_len(0) { }
1211
1212    constexpr
1213    network_v4(const address_v4& __addr, int __prefix_len)
1214    : _M_addr(__addr), _M_prefix_len(__prefix_len)
1215    {
1216      if (_M_prefix_len < 0 || _M_prefix_len > 32)
1217	__throw_out_of_range("network_v4: invalid prefix length");
1218    }
1219
1220    constexpr
1221    network_v4(const address_v4& __addr, const address_v4& __mask)
1222    : _M_addr(__addr), _M_prefix_len(__builtin_popcount(__mask.to_uint()))
1223    {
1224      if (_M_prefix_len != 0)
1225	{
1226	  address_v4::uint_type __mask_uint = __mask.to_uint();
1227	  if (__builtin_ctz(__mask_uint) != (32 - _M_prefix_len))
1228	    __throw_invalid_argument("network_v4: invalid mask");
1229	  if ((__mask_uint & 0x80000000) == 0)
1230	    __throw_invalid_argument("network_v4: invalid mask");
1231	}
1232    }
1233
1234    // members:
1235
1236    constexpr address_v4 address() const noexcept { return _M_addr; }
1237    constexpr int prefix_length() const noexcept { return _M_prefix_len; }
1238
1239    constexpr address_v4
1240    netmask() const noexcept
1241    {
1242      address_v4::uint_type __val = address_v4::broadcast().to_uint();
1243      __val >>= (32 - _M_prefix_len);
1244      __val <<= (32 - _M_prefix_len);
1245      return address_v4{__val};
1246    }
1247
1248    constexpr address_v4
1249    network() const noexcept
1250    { return address_v4{_M_addr.to_uint() & netmask().to_uint()}; }
1251
1252    constexpr address_v4
1253    broadcast() const noexcept
1254    { return address_v4{_M_addr.to_uint() | ~netmask().to_uint()}; }
1255
1256    address_v4_range
1257    hosts() const noexcept
1258    {
1259      if (is_host())
1260	return { address(), *++address_v4_iterator(address()) };
1261      return { network(), broadcast() };
1262    }
1263
1264    constexpr network_v4
1265    canonical() const noexcept
1266    { return network_v4(network(), prefix_length()); }
1267
1268    constexpr bool is_host() const noexcept { return _M_prefix_len == 32; }
1269
1270    constexpr bool
1271    is_subnet_of(const network_v4& __other) const noexcept
1272    {
1273      if (__other.prefix_length() < prefix_length())
1274	{
1275	  network_v4 __net(address(), __other.prefix_length());
1276	  return __net.canonical() == __other.canonical();
1277	}
1278      return false;
1279    }
1280
1281    template<typename _Allocator = allocator<char>>
1282      __string_with<_Allocator>
1283      to_string(const _Allocator& __a = _Allocator()) const
1284      {
1285	return address().to_string(__a) + '/'
1286	  + std::to_string(prefix_length());
1287      }
1288
1289  private:
1290    address_v4 _M_addr;
1291    int _M_prefix_len;
1292  };
1293
1294  /// An IPv6 network address.
1295  class network_v6
1296  {
1297  public:
1298    // constructors:
1299    constexpr network_v6() noexcept : _M_addr(), _M_prefix_len(0) { }
1300
1301    constexpr
1302    network_v6(const address_v6& __addr, int __prefix_len)
1303    : _M_addr(__addr), _M_prefix_len(__prefix_len)
1304    {
1305      if (_M_prefix_len < 0 || _M_prefix_len > 128)
1306	__throw_out_of_range("network_v6: invalid prefix length");
1307    }
1308
1309    // members:
1310    constexpr address_v6 address() const noexcept { return _M_addr; }
1311    constexpr int prefix_length() const noexcept { return _M_prefix_len; }
1312
1313    constexpr address_v6 network() const noexcept; // TODO
1314
1315    address_v6_range
1316    hosts() const noexcept
1317    {
1318      if (is_host())
1319	return { address(), *++address_v6_iterator(address()) };
1320      return {}; // { network(), XXX broadcast() XXX }; // TODO
1321    }
1322
1323    constexpr network_v6
1324    canonical() const noexcept
1325    { return network_v6{network(), prefix_length()}; }
1326
1327    constexpr bool is_host() const noexcept { return _M_prefix_len == 128; }
1328
1329    constexpr bool
1330    is_subnet_of(const network_v6& __other) const noexcept
1331    {
1332      if (__other.prefix_length() < prefix_length())
1333	{
1334	  network_v6 __net(address(), __other.prefix_length());
1335	  return __net.canonical() == __other.canonical();
1336	}
1337      return false;
1338    }
1339
1340    template<typename _Allocator = allocator<char>>
1341      __string_with<_Allocator>
1342      to_string(const _Allocator& __a = _Allocator()) const
1343      {
1344	return address().to_string(__a) + '/'
1345	  + std::to_string(prefix_length());
1346      }
1347
1348  private:
1349    address_v6 _M_addr;
1350    int _M_prefix_len;
1351  };
1352
1353
1354  /** ip::network_v4 comparisons
1355   * @{
1356   */
1357
1358  inline bool
1359  operator==(const network_v4& __a, const network_v4& __b) noexcept
1360  {
1361    return __a.address() == __b.address()
1362      && __a.prefix_length() == __b.prefix_length();
1363  }
1364
1365  inline bool
1366  operator!=(const network_v4& __a, const network_v4& __b) noexcept
1367  { return !(__a == __b); }
1368
1369  /// @}
1370
1371  /** ip::network_v6 comparisons
1372   * @{
1373   */
1374
1375  inline bool
1376  operator==(const network_v6& __a, const network_v6& __b) noexcept
1377  {
1378    return __a.address() == __b.address()
1379      && __a.prefix_length() == __b.prefix_length();
1380  }
1381
1382  inline bool
1383  operator!=(const network_v6& __a, const network_v6& __b) noexcept
1384  { return !(__a == __b); }
1385
1386  /// @}
1387
1388  /** ip::network_v4 creation
1389   * @{
1390   */
1391
1392  inline network_v4
1393  make_network_v4(const address_v4& __a, int __prefix_len)
1394  { return network_v4{__a, __prefix_len}; }
1395
1396  inline network_v4
1397  make_network_v4(const address_v4& __a, const address_v4& __mask)
1398  { return network_v4{ __a, __mask }; }
1399
1400  network_v4 make_network_v4(const char*, error_code&) noexcept; // TODO
1401
1402  inline network_v4
1403  make_network_v4(const char* __str)
1404  { return make_network_v4(__str, __throw_on_error{"make_network_v4"}); }
1405
1406  network_v4 make_network_v4(const string&, error_code&) noexcept; // TODO
1407
1408  inline network_v4
1409  make_network_v4(const string& __str)
1410  { return make_network_v4(__str, __throw_on_error{"make_network_v4"}); }
1411
1412  network_v4 make_network_v4(string_view, error_code&) noexcept; // TODO
1413
1414  inline network_v4
1415  make_network_v4(string_view __str)
1416  { return make_network_v4(__str, __throw_on_error{"make_network_v4"}); }
1417
1418  /// @}
1419
1420  /** ip::network_v6 creation
1421   * @{
1422   */
1423
1424  inline network_v6
1425  make_network_v6(const address_v6& __a, int __prefix_len)
1426  { return network_v6{__a, __prefix_len}; }
1427
1428  network_v6 make_network_v6(const char*, error_code&) noexcept; // TODO
1429
1430  inline network_v6
1431  make_network_v6(const char* __str)
1432  { return make_network_v6(__str, __throw_on_error{"make_network_v6"}); }
1433
1434  network_v6 make_network_v6(const string&, error_code&) noexcept; // TODO
1435
1436  inline network_v6
1437  make_network_v6(const string& __str)
1438  { return make_network_v6(__str, __throw_on_error{"make_network_v6"}); }
1439
1440  network_v6 make_network_v6(string_view, error_code&) noexcept; // TODO
1441
1442  inline network_v6
1443  make_network_v6(string_view __str)
1444  { return make_network_v6(__str, __throw_on_error{"make_network_v6"}); }
1445
1446  /// @}
1447
1448  /// ip::network_v4 I/O
1449  template<typename _CharT, typename _Traits>
1450    inline basic_ostream<_CharT, _Traits>&
1451    operator<<(basic_ostream<_CharT, _Traits>& __os, const network_v4& __net)
1452    { return __os << __net.to_string(); }
1453
1454  /// ip::network_v6 I/O
1455  template<typename _CharT, typename _Traits>
1456    inline basic_ostream<_CharT, _Traits>&
1457    operator<<(basic_ostream<_CharT, _Traits>& __os, const network_v6& __net)
1458    { return __os << __net.to_string(); }
1459
1460  /// An IP endpoint.
1461  template<typename _InternetProtocol>
1462    class basic_endpoint
1463    {
1464    public:
1465      // types:
1466      using protocol_type = _InternetProtocol;
1467
1468      // constructors:
1469
1470      constexpr
1471      basic_endpoint() noexcept : _M_data()
1472      { _M_data._M_v4.sin_family = protocol_type::v4().family(); }
1473
1474      constexpr
1475      basic_endpoint(const protocol_type& __proto,
1476		     port_type __port_num) noexcept
1477      : _M_data()
1478      {
1479	__glibcxx_assert(__proto == protocol_type::v4()
1480			  || __proto == protocol_type::v6());
1481
1482	_M_data._M_v4.sin_family = __proto.family();
1483	_M_data._M_v4.sin_port = address_v4::_S_hton_16(__port_num);
1484      }
1485
1486      constexpr
1487      basic_endpoint(const ip::address& __addr,
1488		     port_type __port_num) noexcept
1489      : _M_data()
1490      {
1491	if (__addr.is_v4())
1492	  {
1493	    _M_data._M_v4.sin_family = protocol_type::v4().family();
1494	    _M_data._M_v4.sin_port = address_v4::_S_hton_16(__port_num);
1495	    _M_data._M_v4.sin_addr.s_addr = __addr._M_v4._M_addr;
1496	  }
1497	else
1498	  {
1499	    _M_data._M_v6 = {};
1500	    _M_data._M_v6.sin6_family = protocol_type::v6().family();
1501	    _M_data._M_v6.sin6_port = address_v4::_S_hton_16(__port_num);
1502	    __builtin_memcpy(_M_data._M_v6.sin6_addr.s6_addr,
1503			     __addr._M_v6._M_bytes.data(), 16);
1504	    _M_data._M_v6.sin6_scope_id = __addr._M_v6._M_scope_id;
1505	  }
1506      }
1507
1508      // members:
1509      constexpr protocol_type protocol() const noexcept
1510      {
1511	return _M_is_v6() ? protocol_type::v6() : protocol_type::v4();
1512      }
1513
1514      constexpr ip::address
1515      address() const noexcept
1516      {
1517	ip::address __addr;
1518	if (_M_is_v6())
1519	  {
1520	    __builtin_memcpy(&__addr._M_v6._M_bytes,
1521			     _M_data._M_v6.sin6_addr.s6_addr, 16);
1522	    __addr._M_is_v4 = false;
1523	  }
1524	else
1525	  {
1526	    __builtin_memcpy(&__addr._M_v4._M_addr,
1527			     &_M_data._M_v4.sin_addr.s_addr, 4);
1528	  }
1529	return __addr;
1530      }
1531
1532      void
1533      address(const ip::address& __addr) noexcept
1534      {
1535	if (__addr.is_v6())
1536	  {
1537	    _M_data._M_v6 = {};
1538	    _M_data._M_v6.sin6_family = protocol_type::v6().family();
1539	    __builtin_memcpy(_M_data._M_v6.sin6_addr.s6_addr,
1540			     __addr._M_v6._M_bytes.data(), 16);
1541	    _M_data._M_v6.sin6_scope_id = __addr._M_v6._M_scope_id;
1542	  }
1543	else
1544	  {
1545	    _M_data._M_v4.sin_family = protocol_type::v4().family();
1546	    _M_data._M_v4.sin_addr.s_addr = __addr._M_v4._M_addr;
1547	  }
1548      }
1549
1550      constexpr port_type
1551      port() const noexcept
1552      { return address_v4::_S_ntoh_16(_M_data._M_v4.sin_port); }
1553
1554      void
1555      port(port_type __port_num) noexcept
1556      { _M_data._M_v4.sin_port = address_v4::_S_hton_16(__port_num); }
1557
1558      void* data() noexcept { return &_M_data; }
1559
1560      const void* data() const noexcept { return &_M_data; }
1561
1562      constexpr size_t size() const noexcept
1563      { return _M_is_v6() ? sizeof(sockaddr_in6) : sizeof(sockaddr_in); }
1564
1565      void
1566      resize(size_t __s)
1567      {
1568	if (__s != size())
1569	  __throw_length_error("net::ip::basic_endpoint::resize");
1570      }
1571
1572      constexpr size_t capacity() const noexcept { return sizeof(_M_data); }
1573
1574    private:
1575      union
1576      {
1577	sockaddr_in	_M_v4;
1578	sockaddr_in6	_M_v6;
1579      } _M_data;
1580
1581      constexpr bool _M_is_v6() const noexcept
1582      { return _M_data._M_v4.sin_family == AF_INET6; }
1583    };
1584
1585  /** basic_endpoint comparisons
1586   * @{
1587   */
1588
1589  template<typename _InternetProtocol>
1590    inline bool
1591    operator==(const basic_endpoint<_InternetProtocol>& __a,
1592	       const basic_endpoint<_InternetProtocol>& __b)
1593    { return __a.address() == __b.address() && __a.port() == __b.port(); }
1594
1595  template<typename _InternetProtocol>
1596    inline bool
1597    operator!=(const basic_endpoint<_InternetProtocol>& __a,
1598	       const basic_endpoint<_InternetProtocol>& __b)
1599    { return !(__a == __b); }
1600
1601  template<typename _InternetProtocol>
1602    inline bool
1603    operator< (const basic_endpoint<_InternetProtocol>& __a,
1604	       const basic_endpoint<_InternetProtocol>& __b)
1605    {
1606      return __a.address() < __b.address()
1607	|| (!(__b.address() < __a.address()) && __a.port() < __b.port());
1608    }
1609
1610  template<typename _InternetProtocol>
1611    inline bool
1612    operator> (const basic_endpoint<_InternetProtocol>& __a,
1613	       const basic_endpoint<_InternetProtocol>& __b)
1614    { return __b < __a; }
1615
1616  template<typename _InternetProtocol>
1617    inline bool
1618    operator<=(const basic_endpoint<_InternetProtocol>& __a,
1619	       const basic_endpoint<_InternetProtocol>& __b)
1620    { return !(__b < __a); }
1621
1622  template<typename _InternetProtocol>
1623    inline bool
1624    operator>=(const basic_endpoint<_InternetProtocol>& __a,
1625	       const basic_endpoint<_InternetProtocol>& __b)
1626    { return !(__a < __b); }
1627
1628  /// @}
1629
1630  /// basic_endpoint I/O
1631  template<typename _CharT, typename _Traits, typename _InternetProtocol>
1632    inline basic_ostream<_CharT, _Traits>&
1633    operator<<(basic_ostream<_CharT, _Traits>& __os,
1634	       const basic_endpoint<_InternetProtocol>& __ep)
1635    {
1636      basic_ostringstream<_CharT, _Traits> __ss;
1637      if (__ep.protocol()
1638	  == basic_endpoint<_InternetProtocol>::protocol_type::v6())
1639	__ss << '[' << __ep.address() << ']';
1640      else
1641	__ss << __ep.address();
1642      __ss << ':' << __ep.port();
1643      __os << __ss.str();
1644      return __os;
1645    }
1646
1647  /** Type representing a single result of name/address resolution.
1648   * @{
1649   */
1650
1651  template<typename _InternetProtocol>
1652    class basic_resolver_entry
1653    {
1654    public:
1655      // types:
1656      using protocol_type = _InternetProtocol;
1657      using endpoint_type = typename _InternetProtocol::endpoint;
1658
1659      // constructors:
1660      basic_resolver_entry() { }
1661
1662      basic_resolver_entry(const endpoint_type& __ep,
1663			   string_view __h, string_view __s)
1664      : _M_ep(__ep), _M_host(__h), _M_svc(__s) { }
1665
1666      // members:
1667      endpoint_type endpoint() const { return _M_ep; }
1668      operator endpoint_type() const { return _M_ep; }
1669
1670      template<typename _Allocator = allocator<char>>
1671	__string_with<_Allocator>
1672	host_name(const _Allocator& __a = _Allocator()) const
1673	{ return { _M_host, __a }; }
1674
1675      template<typename _Allocator = allocator<char>>
1676	__string_with<_Allocator>
1677	service_name(const _Allocator& __a = _Allocator()) const
1678	{ return { _M_svc, __a }; }
1679
1680    private:
1681      basic_endpoint<_InternetProtocol> _M_ep;
1682      string _M_host;
1683      string _M_svc;
1684    };
1685
1686  template<typename _InternetProtocol>
1687    inline bool
1688    operator==(const basic_resolver_entry<_InternetProtocol>& __a,
1689	       const basic_resolver_entry<_InternetProtocol>& __b)
1690    {
1691      return __a.endpoint() == __b.endpoint()
1692	&& __a.host_name() == __b.host_name()
1693	&& __a.service_name() == __b.service_name();
1694    }
1695
1696  template<typename _InternetProtocol>
1697    inline bool
1698    operator!=(const basic_resolver_entry<_InternetProtocol>& __a,
1699	       const basic_resolver_entry<_InternetProtocol>& __b)
1700    { return !(__a == __b); }
1701
1702  /// @}
1703
1704  /** Base class defining flags for name/address resolution.
1705   * @{
1706   */
1707
1708  class resolver_base
1709  {
1710  public:
1711    enum flags : int { };
1712    static constexpr flags passive		= (flags)AI_PASSIVE;
1713    static constexpr flags canonical_name	= (flags)AI_CANONNAME;
1714    static constexpr flags numeric_host		= (flags)AI_NUMERICHOST;
1715#ifdef AI_NUMERICSERV
1716    static constexpr flags numeric_service	= (flags)AI_NUMERICSERV;
1717#endif
1718#ifdef AI_V4MAPPED
1719    static constexpr flags v4_mapped		= (flags)AI_V4MAPPED;
1720#endif
1721#ifdef AI_ALL
1722    static constexpr flags all_matching		= (flags)AI_ALL;
1723#endif
1724#ifdef AI_ADDRCONFIG
1725    static constexpr flags address_configured	= (flags)AI_ADDRCONFIG;
1726#endif
1727
1728    friend constexpr flags
1729    operator&(flags __f1, flags __f2) noexcept
1730    { return flags( int(__f1) & int(__f2) ); }
1731
1732    friend constexpr flags
1733    operator|(flags __f1, flags __f2) noexcept
1734    { return flags( int(__f1) | int(__f2) ); }
1735
1736    friend constexpr flags
1737    operator^(flags __f1, flags __f2) noexcept
1738    { return flags( int(__f1) ^ int(__f2) ); }
1739
1740    friend constexpr flags
1741    operator~(flags __f) noexcept
1742    { return flags( ~int(__f) ); }
1743
1744    friend constexpr flags&
1745    operator&=(flags& __f1, flags __f2) noexcept
1746    { return __f1 = (__f1 & __f2); }
1747
1748    friend constexpr flags&
1749    operator|=(flags& __f1, flags __f2) noexcept
1750    { return __f1 = (__f1 | __f2); }
1751
1752    friend constexpr flags&
1753    operator^=(flags& __f1, flags __f2) noexcept
1754    { return __f1 = (__f1 ^ __f2); }
1755
1756  protected:
1757    resolver_base() = default;
1758    ~resolver_base() = default;
1759  };
1760
1761  // TODO define resolver_base::flags static constants in .so for C++14 mode
1762
1763  /// @}
1764
1765  /** Container for results of name/address resolution.
1766   * @{
1767   */
1768
1769  template<typename _InternetProtocol>
1770    class basic_resolver_results
1771    {
1772    public:
1773      // types:
1774      using protocol_type = _InternetProtocol;
1775      using endpoint_type = typename protocol_type::endpoint;
1776      using value_type = basic_resolver_entry<protocol_type>;
1777      using const_reference = const value_type&;
1778      using reference = value_type&;
1779      using const_iterator = typename forward_list<value_type>::const_iterator;
1780      using iterator = const_iterator;
1781      using difference_type = ptrdiff_t;
1782      using size_type = size_t;
1783
1784      // construct / copy / destroy:
1785
1786      basic_resolver_results() = default;
1787
1788      basic_resolver_results(const basic_resolver_results&) = default;
1789
1790      basic_resolver_results(basic_resolver_results&&) noexcept = default;
1791
1792      basic_resolver_results&
1793      operator=(const basic_resolver_results&) = default;
1794
1795      basic_resolver_results&
1796      operator=(basic_resolver_results&&) = default;
1797
1798      ~basic_resolver_results() = default;
1799
1800      // size:
1801      size_type size() const noexcept { return _M_size; }
1802      size_type max_size() const noexcept { return _M_results.max_size(); }
1803
1804      _GLIBCXX_NODISCARD bool
1805      empty() const noexcept { return _M_results.empty(); }
1806
1807      // element access:
1808      const_iterator begin() const { return _M_results.begin(); }
1809      const_iterator end() const { return _M_results.end(); }
1810      const_iterator cbegin() const { return _M_results.begin(); }
1811      const_iterator cend() const { return _M_results.end(); }
1812
1813      // swap:
1814      void
1815      swap(basic_resolver_results& __that) noexcept
1816      { _M_results.swap(__that._M_results); }
1817
1818    private:
1819      friend class basic_resolver<protocol_type>;
1820
1821      basic_resolver_results(string_view, string_view, resolver_base::flags,
1822			     error_code&, protocol_type* = nullptr);
1823
1824      basic_resolver_results(const endpoint_type&, error_code&);
1825
1826      forward_list<value_type> _M_results;
1827      size_t _M_size = 0;
1828    };
1829
1830  template<typename _InternetProtocol>
1831    inline bool
1832    operator==(const basic_resolver_results<_InternetProtocol>& __a,
1833	       const basic_resolver_results<_InternetProtocol>& __b)
1834    {
1835      return __a.size() == __b.size()
1836	&& std::equal(__a.begin(), __a.end(), __b.begin());
1837    }
1838
1839  template<typename _InternetProtocol>
1840    inline bool
1841    operator!=(const basic_resolver_results<_InternetProtocol>& __a,
1842	       const basic_resolver_results<_InternetProtocol>& __b)
1843    { return !(__a == __b); }
1844
1845  /// @}
1846
1847  /// Perform name/address resolution.
1848  template<typename _InternetProtocol>
1849    class basic_resolver : public resolver_base
1850    {
1851    public:
1852      // types:
1853
1854      using executor_type = io_context::executor_type;
1855      using protocol_type = _InternetProtocol;
1856      using endpoint_type = typename _InternetProtocol::endpoint;
1857      using results_type = basic_resolver_results<_InternetProtocol>;
1858
1859      // construct / copy / destroy:
1860
1861      explicit basic_resolver(io_context& __ctx) : _M_ctx(&__ctx) { }
1862
1863      basic_resolver(const basic_resolver&) = delete;
1864
1865      basic_resolver(basic_resolver&& __rhs) noexcept
1866      : _M_ctx(__rhs._M_ctx)
1867      { } // TODO move state/tasks etc.
1868
1869      ~basic_resolver() { cancel(); }
1870
1871      basic_resolver& operator=(const basic_resolver&) = delete;
1872
1873      basic_resolver& operator=(basic_resolver&& __rhs)
1874      {
1875	cancel();
1876	_M_ctx = __rhs._M_ctx;
1877	// TODO move state/tasks etc.
1878	return *this;
1879      }
1880
1881      // basic_resolver operations:
1882
1883      executor_type get_executor() noexcept { return _M_ctx->get_executor(); }
1884
1885      void cancel() { } // TODO
1886
1887      results_type
1888      resolve(string_view __host_name, string_view __service_name)
1889      {
1890	return resolve(__host_name, __service_name, resolver_base::flags(),
1891		       __throw_on_error{"basic_resolver::resolve"});
1892      }
1893
1894      results_type
1895      resolve(string_view __host_name, string_view __service_name,
1896	      error_code& __ec)
1897      {
1898	return resolve(__host_name, __service_name, resolver_base::flags(),
1899		       __ec);
1900      }
1901
1902      results_type
1903      resolve(string_view __host_name, string_view __service_name, flags __f)
1904      {
1905	return resolve(__host_name, __service_name, __f,
1906		       __throw_on_error{"basic_resolver::resolve"});
1907      }
1908
1909      results_type
1910      resolve(string_view __host_name, string_view __service_name, flags __f,
1911	      error_code& __ec)
1912      { return {__host_name, __service_name, __f, __ec}; }
1913
1914      template<typename _CompletionToken>
1915	__deduced_t<_CompletionToken, void(error_code, results_type)>
1916	async_resolve(string_view __host_name, string_view __service_name,
1917		      _CompletionToken&& __token)
1918	{
1919	  return async_resolve(__host_name, __service_name,
1920			       resolver_base::flags(),
1921			       forward<_CompletionToken>(__token));
1922	}
1923
1924      template<typename _CompletionToken>
1925	__deduced_t<_CompletionToken, void(error_code, results_type)>
1926	async_resolve(string_view __host_name, string_view __service_name,
1927		      flags __f, _CompletionToken&& __token); // TODO
1928
1929      results_type
1930      resolve(const protocol_type& __protocol,
1931	      string_view __host_name, string_view __service_name)
1932      {
1933	return resolve(__protocol, __host_name, __service_name,
1934		       resolver_base::flags(),
1935		       __throw_on_error{"basic_resolver::resolve"});
1936      }
1937
1938      results_type
1939      resolve(const protocol_type& __protocol,
1940	      string_view __host_name, string_view __service_name,
1941	      error_code& __ec)
1942      {
1943	return resolve(__protocol, __host_name, __service_name,
1944		       resolver_base::flags(), __ec);
1945      }
1946
1947      results_type
1948      resolve(const protocol_type& __protocol,
1949	      string_view __host_name, string_view __service_name, flags __f)
1950      {
1951	return resolve(__protocol, __host_name, __service_name, __f,
1952		       __throw_on_error{"basic_resolver::resolve"});
1953      }
1954
1955      results_type
1956      resolve(const protocol_type& __protocol,
1957	      string_view __host_name, string_view __service_name,
1958	      flags __f, error_code& __ec)
1959      { return {__host_name, __service_name, __f, __ec, &__protocol}; }
1960
1961      template<typename _CompletionToken>
1962	__deduced_t<_CompletionToken, void(error_code, results_type)>
1963	async_resolve(const protocol_type& __protocol,
1964		      string_view __host_name, string_view __service_name,
1965		      _CompletionToken&& __token)
1966	{
1967	  return async_resolve(__protocol, __host_name, __service_name,
1968			       resolver_base::flags(),
1969			       forward<_CompletionToken>(__token));
1970	}
1971
1972      template<typename _CompletionToken>
1973	__deduced_t<_CompletionToken, void(error_code, results_type)>
1974	async_resolve(const protocol_type& __protocol,
1975		      string_view __host_name, string_view __service_name,
1976		      flags __f, _CompletionToken&& __token); // TODO
1977
1978      results_type
1979      resolve(const endpoint_type& __ep)
1980      { return resolve(__ep, __throw_on_error{"basic_resolver::resolve"}); }
1981
1982      results_type
1983      resolve(const endpoint_type& __ep, error_code& __ec)
1984      { return { __ep, __ec }; }
1985
1986      template<typename _CompletionToken> // TODO
1987	__deduced_t<_CompletionToken, void(error_code, results_type)>
1988	async_resolve(const endpoint_type& __ep, _CompletionToken&& __token);
1989
1990    private:
1991      io_context* _M_ctx;
1992    };
1993
1994  /// Private constructor to synchronously resolve host and service names.
1995  template<typename _InternetProtocol>
1996    basic_resolver_results<_InternetProtocol>::
1997    basic_resolver_results(string_view __host_name, string_view __service_name,
1998			   resolver_base::flags __f, error_code& __ec,
1999			   protocol_type* __protocol)
2000    {
2001#ifdef _GLIBCXX_HAVE_NETDB_H
2002      string __host;
2003      const char* __h = __host_name.data()
2004	? (__host = __host_name.to_string()).c_str()
2005	: nullptr;
2006      string __svc;
2007      const char* __s = __service_name.data()
2008	? (__svc = __service_name.to_string()).c_str()
2009	: nullptr;
2010
2011      ::addrinfo __hints{ };
2012      __hints.ai_flags = static_cast<int>(__f);
2013      if (__protocol)
2014	{
2015	  __hints.ai_family = __protocol->family();
2016	  __hints.ai_socktype = __protocol->type();
2017	  __hints.ai_protocol = __protocol->protocol();
2018	}
2019      else
2020	{
2021	  auto __p = endpoint_type{}.protocol();
2022	  __hints.ai_family = AF_UNSPEC;
2023	  __hints.ai_socktype = __p.type();
2024	  __hints.ai_protocol = __p.protocol();
2025	}
2026
2027      struct __scoped_addrinfo
2028      {
2029	~__scoped_addrinfo() { if (_M_p) ::freeaddrinfo(_M_p); }
2030	::addrinfo* _M_p = nullptr;
2031      } __sai;
2032
2033      if (int __err = ::getaddrinfo(__h, __s, &__hints, &__sai._M_p))
2034	{
2035	  __ec = ip::__make_resolver_error_code(__err, errno);
2036	  return;
2037	}
2038      __ec.clear();
2039
2040      endpoint_type __ep;
2041      auto __tail = _M_results.before_begin();
2042      for (auto __ai = __sai._M_p; __ai != nullptr; __ai = __ai->ai_next)
2043	{
2044	  if (__ai->ai_family == AF_INET || __ai->ai_family == AF_INET6)
2045	    {
2046	      if (__ai->ai_addrlen <= __ep.capacity())
2047		__builtin_memcpy(__ep.data(), __ai->ai_addr, __ai->ai_addrlen);
2048	      __ep.resize(__ai->ai_addrlen);
2049	      __tail = _M_results.emplace_after(__tail, __ep, __host, __svc);
2050	      _M_size++;
2051	    }
2052	}
2053#else
2054      __ec = std::make_error_code(errc::operation_not_supported);
2055#endif
2056    }
2057
2058  /// Private constructor to synchronously resolve an endpoint.
2059  template<typename _InternetProtocol>
2060    basic_resolver_results<_InternetProtocol>::
2061    basic_resolver_results(const endpoint_type& __ep, error_code& __ec)
2062    {
2063#ifdef _GLIBCXX_HAVE_NETDB_H
2064      char __host_name[1025];	// glibc NI_MAXHOST
2065      char __service_name[32];  // glibc NI_MAXSERV
2066      int __flags = 0;
2067      if (__ep.protocol().type() == SOCK_DGRAM)
2068	__flags |= NI_DGRAM;
2069      auto __sa = static_cast<const sockaddr*>(__ep.data());
2070      int __err = ::getnameinfo(__sa, __ep.size(),
2071				__host_name, sizeof(__host_name),
2072				__service_name, sizeof(__service_name),
2073				__flags);
2074      if (__err)
2075	{
2076	  __flags |= NI_NUMERICSERV;
2077	  __err = ::getnameinfo(__sa, __ep.size(),
2078				__host_name, sizeof(__host_name),
2079				__service_name, sizeof(__service_name),
2080				__flags);
2081	}
2082      if (__err)
2083	__ec = ip::__make_resolver_error_code(__err, errno);
2084      else
2085	{
2086	  __ec.clear();
2087	  _M_results.emplace_front(__ep, __host_name, __service_name);
2088	  _M_size = 1;
2089	}
2090#else
2091      __ec = std::make_error_code(errc::operation_not_supported);
2092#endif
2093    }
2094
2095  /** The name of the local host.
2096   * @{
2097   */
2098
2099  template<typename _Allocator>
2100    __string_with<_Allocator>
2101    host_name(const _Allocator& __a, error_code& __ec)
2102    {
2103#ifdef HOST_NAME_MAX
2104      constexpr size_t __maxlen = HOST_NAME_MAX;
2105#else
2106      constexpr size_t __maxlen = 256;
2107#endif
2108      char __buf[__maxlen + 1];
2109      if (::gethostname(__buf, __maxlen) == -1)
2110	__ec.assign(errno, generic_category());
2111      __buf[__maxlen] = '\0';
2112      return { __buf, __a };
2113    }
2114
2115  template<typename _Allocator>
2116    inline __string_with<_Allocator>
2117    host_name(const _Allocator& __a)
2118    { return host_name(__a, __throw_on_error{"host_name"}); }
2119
2120  inline string
2121  host_name(error_code& __ec)
2122  { return host_name(std::allocator<char>{}, __ec); }
2123
2124  inline string
2125  host_name()
2126  { return host_name(std::allocator<char>{}, __throw_on_error{"host_name"}); }
2127
2128  /// @}
2129
2130#ifdef IPPROTO_TCP
2131  /// The TCP byte-stream protocol.
2132  class tcp
2133  {
2134  public:
2135    // types:
2136    using endpoint = basic_endpoint<tcp>;	 ///< A TCP endpoint.
2137    using resolver = basic_resolver<tcp>;	 ///< A TCP resolver.
2138    using socket = basic_stream_socket<tcp>;	 ///< A TCP socket.
2139    using acceptor = basic_socket_acceptor<tcp>; ///< A TCP acceptor.
2140    using iostream = basic_socket_iostream<tcp>; /// A TCP iostream.
2141
2142#ifdef TCP_NODELAY
2143    /// Disable coalescing of small segments (i.e. the Nagle algorithm).
2144    struct no_delay : __sockopt_crtp<no_delay, bool>
2145    {
2146      using __sockopt_crtp::__sockopt_crtp;
2147      using __sockopt_crtp::operator=;
2148
2149      static const int _S_level = IPPROTO_TCP;
2150      static const int _S_name = TCP_NODELAY;
2151    };
2152#endif
2153
2154    // static members:
2155
2156    /// A protocol object representing IPv4 TCP.
2157    static constexpr tcp v4() noexcept { return tcp(AF_INET); }
2158    /// A protocol object representing IPv6 TCP.
2159    static constexpr tcp v6() noexcept { return tcp(AF_INET6); }
2160
2161    tcp() = delete;
2162
2163    constexpr int family() const noexcept { return _M_family; }
2164    constexpr int type() const noexcept { return SOCK_STREAM; }
2165    constexpr int protocol() const noexcept { return IPPROTO_TCP; }
2166
2167  private:
2168    constexpr explicit tcp(int __family) : _M_family(__family) { }
2169
2170    int _M_family;
2171  };
2172
2173  /** tcp comparisons
2174   * @{
2175   */
2176
2177  constexpr bool
2178  operator==(const tcp& __a, const tcp& __b) noexcept
2179  { return __a.family() == __b.family(); }
2180
2181  constexpr bool
2182  operator!=(const tcp& __a, const tcp& __b) noexcept
2183  { return !(__a == __b); }
2184
2185  /// @}
2186#endif // IPPROTO_TCP
2187
2188#ifdef IPPROTO_UDP
2189  /// The UDP datagram protocol.
2190  class udp
2191  {
2192  public:
2193    // types:
2194    using endpoint = basic_endpoint<udp>;
2195    using resolver = basic_resolver<udp>;
2196    using socket = basic_datagram_socket<udp>;
2197
2198    // static members:
2199    static constexpr udp v4() noexcept { return udp(AF_INET); }
2200    static constexpr udp v6() noexcept { return udp(AF_INET6); }
2201
2202    udp() = delete;
2203
2204    constexpr int family() const noexcept { return _M_family; }
2205    constexpr int type() const noexcept { return SOCK_DGRAM; }
2206    constexpr int protocol() const noexcept { return IPPROTO_UDP; }
2207
2208  private:
2209    constexpr explicit udp(int __family) : _M_family(__family) { }
2210
2211    int _M_family;
2212  };
2213
2214  /** udp comparisons
2215   * @{
2216   */
2217
2218  constexpr bool
2219  operator==(const udp& __a, const udp& __b) noexcept
2220  { return __a.family() == __b.family(); }
2221
2222  constexpr bool
2223  operator!=(const udp& __a, const udp& __b) noexcept
2224  { return !(__a == __b); }
2225
2226  /// @}
2227#endif // IPPROTO_UDP
2228
2229#if defined IPPROTO_IP && defined IPPROTO_IPV6
2230
2231  /// Restrict a socket created for an IPv6 protocol to IPv6 only.
2232  class v6_only : public __sockopt_crtp<v6_only, bool>
2233  {
2234  public:
2235    using __sockopt_crtp::__sockopt_crtp;
2236    using __sockopt_crtp::operator=;
2237
2238  private:
2239    friend __sockopt_crtp<v6_only, bool>;
2240    static const int _S_level = IPPROTO_IPV6;
2241    static const int _S_name = IPV6_V6ONLY;
2242  };
2243
2244  namespace unicast
2245  {
2246    /// Set the default number of hops (TTL) for outbound datagrams.
2247    class hops : public __sockopt_crtp<hops>
2248    {
2249    public:
2250      using __sockopt_crtp::__sockopt_crtp;
2251      using __sockopt_crtp::operator=;
2252
2253      template<typename _Protocol>
2254	int
2255	level(const _Protocol& __p) const noexcept
2256	{ return __p.family() == AF_INET6 ? IPPROTO_IPV6 : IPPROTO_IP; }
2257
2258      template<typename _Protocol>
2259	int
2260	name(const _Protocol& __p) const noexcept
2261	{ return __p.family() == AF_INET6 ? IPV6_UNICAST_HOPS : IP_TTL; }
2262    };
2263  } // namespace unicast
2264
2265  namespace multicast
2266  {
2267    class __mcastopt
2268    {
2269    public:
2270      explicit
2271      __mcastopt(const address& __grp) noexcept
2272      : __mcastopt(__grp.is_v4() ? __mcastopt(__grp.to_v4()) : __mcastopt(__grp.to_v6()))
2273      { }
2274
2275      explicit
2276      __mcastopt(const address_v4& __grp,
2277		 const address_v4& __iface = address_v4::any()) noexcept
2278      {
2279#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
2280	_M_v4.imr_multiaddr.s_addr = __grp.to_uint();
2281	_M_v4.imr_interface.s_addr = __iface.to_uint();
2282#else
2283	_M_v4.imr_multiaddr.s_addr = __builtin_bswap32(__grp.to_uint());
2284	_M_v4.imr_interface.s_addr = __builtin_bswap32(__iface.to_uint());
2285#endif
2286      }
2287
2288      explicit
2289      __mcastopt(const address_v6& __grp, unsigned int __iface = 0) noexcept
2290      {
2291	const auto __addr = __grp.to_bytes();
2292	__builtin_memcpy(_M_v6.ipv6mr_multiaddr.s6_addr, __addr.data(), 16);
2293	_M_v6.ipv6mr_interface = __iface;
2294      }
2295
2296      template<typename _Protocol>
2297	int
2298	level(const _Protocol& __p) const noexcept
2299	{ return __p.family() == AF_INET6 ? IPPROTO_IPV6 : IPPROTO_IP; }
2300
2301      template<typename _Protocol>
2302	const void*
2303	data(const _Protocol& __p) const noexcept
2304	{ return __p.family() == AF_INET6 ? &_M_v6 : &_M_v4; }
2305
2306      template<typename _Protocol>
2307	size_t
2308	size(const _Protocol& __p) const noexcept
2309	{ return __p.family() == AF_INET6 ? sizeof(_M_v6) : sizeof(_M_v4); }
2310
2311    private:
2312      ipv6_mreq _M_v6 = {};
2313      ip_mreq _M_v4 = {};
2314    };
2315
2316    /// Request that a socket joins a multicast group.
2317    class join_group : private __mcastopt
2318    {
2319    public:
2320      using __mcastopt::__mcastopt;
2321      using __mcastopt::level;
2322      using __mcastopt::data;
2323      using __mcastopt::size;
2324
2325      template<typename _Protocol>
2326	int
2327	name(const _Protocol& __p) const noexcept
2328	{
2329	  if (__p.family() == AF_INET6)
2330	    return IPV6_JOIN_GROUP;
2331	  return IP_ADD_MEMBERSHIP;
2332	}
2333    };
2334
2335    /// Request that a socket leaves a multicast group.
2336    class leave_group : private __mcastopt
2337    {
2338    public:
2339      using __mcastopt::__mcastopt;
2340      using __mcastopt::level;
2341      using __mcastopt::data;
2342      using __mcastopt::size;
2343
2344      template<typename _Protocol>
2345	int
2346	name(const _Protocol& __p) const noexcept
2347	{
2348	  if (__p.family() == AF_INET6)
2349	    return IPV6_LEAVE_GROUP;
2350	  return IP_DROP_MEMBERSHIP;
2351	}
2352    };
2353
2354    /// Specify the network interface for outgoing multicast datagrams.
2355    class outbound_interface
2356    {
2357    public:
2358      explicit
2359      outbound_interface(const address_v4& __v4) noexcept
2360      {
2361#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
2362	_M_v4.s_addr = __v4.to_uint();
2363#else
2364	_M_v4.s_addr = __builtin_bswap32(__v4.to_uint());
2365#endif
2366      }
2367
2368      explicit
2369      outbound_interface(unsigned int __v6) noexcept
2370      : _M_v4(), _M_v6(__v6)
2371      { }
2372
2373      template<typename _Protocol>
2374	int
2375	level(const _Protocol& __p) const noexcept
2376	{ return __p.family() == AF_INET6 ? IPPROTO_IPV6 : IPPROTO_IP; }
2377
2378      template<typename _Protocol>
2379	int
2380	name(const _Protocol& __p) const noexcept
2381	{
2382	  return __p.family() == AF_INET6
2383	    ? IPV6_MULTICAST_IF : IP_MULTICAST_IF;
2384	}
2385
2386      template<typename _Protocol>
2387	const void*
2388	data(const _Protocol& __p) const noexcept
2389	{ return __p.family() == AF_INET6 ? &_M_v6 : &_M_v4; }
2390
2391      template<typename _Protocol>
2392	size_t
2393	size(const _Protocol& __p) const noexcept
2394	{ return __p.family() == AF_INET6 ? sizeof(_M_v6) : sizeof(_M_v4); }
2395
2396    private:
2397      in_addr _M_v4;
2398      unsigned _M_v6 = 0;
2399    };
2400
2401    /// Set the default number of hops (TTL) for outbound datagrams.
2402    class hops : public __sockopt_crtp<hops>
2403    {
2404    public:
2405      using __sockopt_crtp::__sockopt_crtp;
2406      using __sockopt_crtp::operator=;
2407
2408      template<typename _Protocol>
2409	int
2410	level(const _Protocol& __p) const noexcept
2411	{ return __p.family() == AF_INET6 ? IPPROTO_IPV6 : IPPROTO_IP; }
2412
2413      template<typename _Protocol>
2414	int
2415	name(const _Protocol& __p) const noexcept
2416	{
2417	  return __p.family() == AF_INET6
2418	    ? IPV6_MULTICAST_HOPS : IP_MULTICAST_TTL;
2419	}
2420    };
2421
2422    /// Set whether datagrams are delivered back to the local application.
2423    class enable_loopback : public __sockopt_crtp<enable_loopback, bool>
2424    {
2425    public:
2426      using __sockopt_crtp::__sockopt_crtp;
2427      using __sockopt_crtp::operator=;
2428
2429      template<typename _Protocol>
2430	int
2431	level(const _Protocol& __p) const noexcept
2432	{ return __p.family() == AF_INET6 ? IPPROTO_IPV6 : IPPROTO_IP; }
2433
2434      template<typename _Protocol>
2435	int
2436	name(const _Protocol& __p) const noexcept
2437	{
2438	  return __p.family() == AF_INET6
2439	    ? IPV6_MULTICAST_LOOP : IP_MULTICAST_LOOP;
2440	}
2441    };
2442
2443  } // namespace multicast
2444
2445#endif // IPPROTO_IP && IPPROTO_IPV6
2446
2447  /// @}
2448
2449} // namespace ip
2450} // namespace v1
2451} // namespace net
2452} // namespace experimental
2453
2454  template<>
2455    struct is_error_condition_enum<experimental::net::v1::ip::resolver_errc>
2456    : public true_type {};
2457
2458  // hash support
2459  template<typename _Tp> struct hash;
2460  template<>
2461    struct hash<experimental::net::v1::ip::address>
2462    : __hash_base<size_t, experimental::net::v1::ip::address>
2463    {
2464      size_t
2465      operator()(const experimental::net::v1::ip::address& __a) const
2466      {
2467	if (__a.is_v4())
2468	  return _Hash_impl::hash(__a.to_v4());
2469	else
2470	  return _Hash_impl::hash(__a.to_v6());
2471      }
2472    };
2473
2474  template<>
2475    struct hash<experimental::net::v1::ip::address_v4>
2476    : __hash_base<size_t, experimental::net::v1::ip::address_v4>
2477    {
2478      size_t
2479      operator()(const experimental::net::v1::ip::address_v4& __a) const
2480      { return _Hash_impl::hash(__a.to_bytes()); }
2481    };
2482
2483  template<> struct hash<experimental::net::v1::ip::address_v6>
2484    : __hash_base<size_t, experimental::net::v1::ip::address_v6>
2485    {
2486      size_t
2487      operator()(const experimental::net::v1::ip::address_v6& __a) const
2488      { return _Hash_impl::hash(__a.to_bytes()); }
2489    };
2490
2491_GLIBCXX_END_NAMESPACE_VERSION
2492} // namespace std
2493
2494#endif // C++14
2495
2496#endif // _GLIBCXX_EXPERIMENTAL_INTERNET
2497