include/boost/corosio/native/detail/endpoint_convert.hpp

99.0% Lines (100 / 101) 100.0% Functions (16 / 16)

[ ] prev/next file n p prev/next uncovered line

endpoint_convert.hpp

f(x) Functions (16)

Function Calls Lines Blocks

Line	Hits	Source Code
1		//
2		// Copyright (c) 2026 Vinnie Falco (vinnie.falco@gmail.com)
3		//
4		// Distributed under the Boost Software License, Version 1.0. (See accompanying
5		// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6		//
7		// Official repository: https://github.com/cppalliance/corosio
8		//
9
10		#ifndef BOOST_COROSIO_NATIVE_DETAIL_ENDPOINT_CONVERT_HPP
11		#define BOOST_COROSIO_NATIVE_DETAIL_ENDPOINT_CONVERT_HPP
12
13		#include <boost/corosio/endpoint.hpp>
14		#include <boost/corosio/family.hpp>
15		#include <boost/corosio/local_endpoint.hpp>
16		#include <boost/corosio/detail/platform.hpp>
17
18		#include <algorithm>
19		#include <cstring>
20
21		#if BOOST_COROSIO_POSIX
22		#include <sys/socket.h>
23		#include <sys/un.h>
24		#include <netinet/in.h>
25		#include <arpa/inet.h>
26		#else
27		#ifndef WIN32_LEAN_AND_MEAN
28		#define WIN32_LEAN_AND_MEAN
29		#endif
30		#ifndef NOMINMAX
31		#define NOMINMAX
32		#endif
33		#include <winsock2.h>
34		#include <ws2tcpip.h>
35		#endif
36
37		#include <cstddef> // offsetof
38		#include <tuple>
39
40		#ifndef AF_UNIX
41		#define AF_UNIX 1
42		#endif
43
44		namespace boost::corosio::detail {
45
46		/** Convert IPv4 endpoint to sockaddr_in.
47
48		@param ep The endpoint to convert. Must be IPv4 (is_v4() == true);
49		a wrong-family endpoint terminates (throwing conversion inside
50		a noexcept function).
51		@return A sockaddr_in structure with fields in network byte order.
52		*/
53		inline sockaddr_in
54	10792x	to_sockaddr_in(endpoint const& ep) noexcept
55		{
56	10792x	sockaddr_in sa{};
57	10792x	sa.sin_family = AF_INET;
58	10792x	sa.sin_port = htons(ep.port());
59	10792x	auto bytes = ep.address().to_v4().to_bytes();
60	10792x	std::memcpy(&sa.sin_addr, bytes.data(), 4);
61	10792x	return sa;
62		}
63
64		/** Convert IPv6 endpoint to sockaddr_in6.
65
66		@param ep The endpoint to convert. Must be IPv6 (is_v6() == true);
67		a wrong-family endpoint terminates (throwing conversion inside
68		a noexcept function).
69		@return A sockaddr_in6 structure with fields in network byte order.
70		*/
71		inline sockaddr_in6
72	56x	to_sockaddr_in6(endpoint const& ep) noexcept
73		{
74	56x	sockaddr_in6 sa{};
75	56x	sa.sin6_family = AF_INET6;
76	56x	sa.sin6_port = htons(ep.port());
77	56x	auto addr = ep.address().to_v6();
78	56x	auto bytes = addr.to_bytes();
79	56x	std::memcpy(&sa.sin6_addr, bytes.data(), 16);
80	56x	sa.sin6_scope_id = addr.scope_id();
81	56x	return sa;
82		}
83
84		/** Create endpoint from sockaddr_in.
85
86		@param sa The sockaddr_in structure with fields in network byte order.
87		@return An endpoint with address and port extracted from sa.
88		*/
89		inline endpoint
90	27155x	from_sockaddr_in(sockaddr_in const& sa) noexcept
91		{
92		ipv4_address::bytes_type bytes;
93	27155x	std::memcpy(bytes.data(), &sa.sin_addr, 4);
94	27155x	return endpoint(ipv4_address(bytes), ntohs(sa.sin_port));
95		}
96
97		/** Create endpoint from sockaddr_in6.
98
99		@param sa The sockaddr_in6 structure with fields in network byte order.
100		@return An endpoint with address and port extracted from sa.
101		*/
102		inline endpoint
103	87x	from_sockaddr_in6(sockaddr_in6 const& sa) noexcept
104		{
105		ipv6_address::bytes_type bytes;
106	87x	std::memcpy(bytes.data(), &sa.sin6_addr, 16);
107	87x	return endpoint(ipv6_address(bytes, sa.sin6_scope_id), ntohs(sa.sin6_port));
108		}
109
110		/** Convert an IPv4 endpoint to an IPv4-mapped IPv6 sockaddr_in6.
111
112		Produces a `sockaddr_in6` with the `::ffff:` prefix, suitable
113		for passing an IPv4 destination to a dual-stack IPv6 socket.
114
115		@param ep The endpoint to convert. Must be IPv4 (is_v4() == true);
116		a wrong-family endpoint terminates (throwing conversion inside
117		a noexcept function).
118		@return A sockaddr_in6 with the IPv4-mapped address.
119		*/
120		inline sockaddr_in6
121	2x	to_v4_mapped_sockaddr_in6(endpoint const& ep) noexcept
122		{
123	2x	sockaddr_in6 sa{};
124	2x	sa.sin6_family = AF_INET6;
125	2x	sa.sin6_port = htons(ep.port());
126		// The mapping constructor supplies the ::ffff:0:0/96 prefix
127	2x	auto bytes = ipv6_address(ep.address().to_v4()).to_bytes();
128	2x	std::memcpy(&sa.sin6_addr, bytes.data(), 16);
129	2x	return sa;
130		}
131
132		/** Convert endpoint to sockaddr_storage.
133
134		Dispatches to @ref to_sockaddr_in or @ref to_sockaddr_in6
135		based on the endpoint's address family.
136
137		@param ep The endpoint to convert.
138		@param storage Output parameter filled with the sockaddr.
139		@return The length of the filled sockaddr structure.
140		*/
141		inline socklen_t
142	10829x	to_sockaddr(endpoint const& ep, sockaddr_storage& storage) noexcept
143		{
144	10829x	std::memset(&storage, 0, sizeof(storage));
145	10829x	if (ep.is_v4())
146		{
147	10778x	auto sa = to_sockaddr_in(ep);
148	10778x	std::memcpy(&storage, &sa, sizeof(sa));
149	10778x	return sizeof(sa);
150		}
151	51x	auto sa6 = to_sockaddr_in6(ep);
152	51x	std::memcpy(&storage, &sa6, sizeof(sa6));
153	51x	return sizeof(sa6);
154		}
155
156		/** Convert endpoint to sockaddr_storage for a specific socket family.
157
158		When the socket is AF_INET6 and the endpoint is IPv4, the address
159		is converted to an IPv4-mapped IPv6 address (`::ffff:x.x.x.x`) so
160		dual-stack sockets can connect to IPv4 destinations.
161
162		@param ep The endpoint to convert.
163		@param socket_family The address family of the socket (AF_INET or
164		AF_INET6).
165		@param storage Output parameter filled with the sockaddr.
166		@return The length of the filled sockaddr structure.
167		*/
168		inline socklen_t
169	8566x	to_sockaddr(
170		endpoint const& ep, int socket_family, sockaddr_storage& storage) noexcept
171		{
172		// IPv4 endpoint on IPv6 socket: use IPv4-mapped address.
173		// The reverse mismatch (v4-mapped IPv6 endpoint on an AF_INET
174		// socket) is deliberately not bridged; the kernel rejects it.
175	8566x	if (ep.is_v4() && socket_family == AF_INET6)
176		{
177	2x	std::memset(&storage, 0, sizeof(storage));
178	2x	auto sa6 = to_v4_mapped_sockaddr_in6(ep);
179	2x	std::memcpy(&storage, &sa6, sizeof(sa6));
180	2x	return sizeof(sa6);
181		}
182	8564x	return to_sockaddr(ep, storage);
183		}
184
185		/** Create endpoint from sockaddr_storage.
186
187		Dispatches on `ss_family` to reconstruct the appropriate
188		IPv4 or IPv6 endpoint.
189
190		@param storage The sockaddr_storage with fields in network byte order.
191		@return An endpoint with address and port extracted from storage.
192		*/
193		inline endpoint
194	27215x	from_sockaddr(sockaddr_storage const& storage) noexcept
195		{
196	27215x	if (storage.ss_family == AF_INET)
197		{
198		sockaddr_in sa;
199	27132x	std::memcpy(&sa, &storage, sizeof(sa));
200	27132x	return from_sockaddr_in(sa);
201		}
202	83x	if (storage.ss_family == AF_INET6)
203		{
204		sockaddr_in6 sa6;
205	83x	std::memcpy(&sa6, &storage, sizeof(sa6));
206	83x	return from_sockaddr_in6(sa6);
207		}
208	✗	return endpoint{};
209		}
210
211		/** Convert a native address family to the portable one.
212
213		@param af The native family (`AF_INET`, `AF_INET6`, or anything
214		else, which maps to v4 as the inert value).
215		@return The portable family.
216		*/
217		inline corosio::family
218	8759x	to_family(int af) noexcept
219		{
220	8759x	return af == AF_INET6 ? corosio::family::v6 : corosio::family::v4;
221		}
222
223		/** Convert the portable address family to the native one.
224
225		@param f The portable family.
226		@return `AF_INET` or `AF_INET6`.
227		*/
228		inline int
229	10987x	native_family(corosio::family f) noexcept
230		{
231	10987x	return f == corosio::family::v6 ? AF_INET6 : AF_INET;
232		}
233
234		/** Return the native address family for an endpoint.
235
236		@param ep The endpoint to query.
237		@return `AF_INET` for IPv4, `AF_INET6` for IPv6.
238		*/
239		inline int
240		endpoint_family(endpoint const& ep) noexcept
241		{
242		return ep.is_v6() ? AF_INET6 : AF_INET;
243		}
244
245		/** Return the address family of a socket descriptor.
246
247		@param fd The socket file descriptor.
248		@return AF_INET, AF_INET6, or AF_UNSPEC on failure.
249		*/
250		inline int
251	17526x	socket_family(
252		#if BOOST_COROSIO_POSIX
253		int fd
254		#else
255		std::uintptr_t fd
256		#endif
257		) noexcept
258		{
259	17526x	sockaddr_storage storage{};
260	17526x	socklen_t len = sizeof(storage);
261	17526x	if (getsockname(
262		#if BOOST_COROSIO_POSIX
263		fd,
264		#else
265		static_cast<SOCKET>(fd),
266		#endif
267	17526x	reinterpret_cast<sockaddr*>(&storage), &len) != 0)
268	2x	return AF_UNSPEC;
269	17524x	return storage.ss_family;
270		}
271
272		//----------------------------------------------------------
273		// local_endpoint (AF_UNIX) conversions
274		//----------------------------------------------------------
275
276		// Platform-agnostic sockaddr_un alias. POSIX uses the real
277		// sockaddr_un from <sys/un.h>; Windows uses a private struct
278		// matching the layout (same approach as Boost.Asio).
279		#if BOOST_COROSIO_POSIX
280		using un_sa_t = sockaddr_un;
281		#else
282		struct un_sa_t
283		{
284		u_short sun_family;
285		char sun_path[108];
286		};
287		#endif
288
289		/** Convert a local_endpoint to sockaddr_storage.
290
291		@param ep The local endpoint to convert.
292		@param storage Output parameter filled with the sockaddr_un.
293		@return The length of the filled sockaddr structure.
294		*/
295		inline socklen_t
296	290x	to_sockaddr(local_endpoint const& ep, sockaddr_storage& storage) noexcept
297		{
298	290x	std::memset(&storage, 0, sizeof(storage));
299	290x	un_sa_t sa{};
300	290x	sa.sun_family = AF_UNIX;
301	290x	auto path = ep.path();
302	580x	auto copy_len = (std::min)(
303	290x	path.size(),
304	290x	(std::min)(local_endpoint::max_path_length, sizeof(sa.sun_path)));
305	290x	if (copy_len > 0)
306	290x	std::memcpy(sa.sun_path, path.data(), copy_len);
307	290x	std::memcpy(&storage, &sa, sizeof(sa));
308
309	290x	if (ep.is_abstract())
310	6x	return static_cast<socklen_t>(offsetof(un_sa_t, sun_path) + copy_len);
311	284x	return static_cast<socklen_t>(sizeof(sa));
312		}
313
314		/** Convert a local_endpoint to sockaddr_storage (family-aware overload).
315
316		The socket_family parameter is ignored for Unix sockets since
317		there is no dual-stack mapping.
318
319		@param ep The local endpoint to convert.
320		@param socket_family Ignored.
321		@param storage Output parameter filled with the sockaddr_un.
322		@return The length of the filled sockaddr structure.
323		*/
324		inline socklen_t
325	201x	to_sockaddr(
326		local_endpoint const& ep,
327		int /socket_family/,
328		sockaddr_storage& storage) noexcept
329		{
330	201x	return to_sockaddr(ep, storage);
331		}
332
333		/** Create a local_endpoint from sockaddr_storage.
334
335		@param storage The sockaddr_storage (must have ss_family == AF_UNIX).
336		@param len The address length returned by the kernel.
337		@return A local_endpoint with the path extracted from the
338		sockaddr_un, or an empty endpoint if the family is not AF_UNIX.
339		*/
340		inline local_endpoint
341	946x	from_sockaddr_local(sockaddr_storage const& storage, socklen_t len) noexcept
342		{
343	946x	if (storage.ss_family != AF_UNIX)
344	1x	return local_endpoint{};
345
346	945x	un_sa_t sa{};
347	945x	std::memcpy(
348	945x	&sa, &storage, (std::min)(static_cast<std::size_t>(len), sizeof(sa)));
349
350	945x	auto path_offset = offsetof(un_sa_t, sun_path);
351	945x	if (static_cast<std::size_t>(len) <= path_offset)
352	707x	return local_endpoint{};
353
354		// Clamp to the buffer: a foreign len may overstate the payload,
355		// and sun_path is the struct's last member.
356	476x	auto path_len = (std::min)(static_cast<std::size_t>(len) - path_offset,
357	238x	sizeof(sa.sun_path));
358
359		// Non-abstract paths may be null-terminated by the kernel
360	238x	if (path_len > 0 && sa.sun_path[0] != '\0')
361		{
362		auto* end =
363	232x	static_cast<char const*>(std::memchr(sa.sun_path, '\0', path_len));
364	232x	if (end)
365	232x	path_len = static_cast<std::size_t>(end - sa.sun_path);
366		}
367
368		// A foreign sun_path may exceed corosio's cap; the factory then
369		// yields the empty endpoint, which is what we return.
370	238x	return std::get<1>(
371	476x	make_local_endpoint(std::string_view(sa.sun_path, path_len)));
372		}
373
374		//----------------------------------------------------------
375		// Tag-dispatch helpers for templatized reactor code.
376		// Overload resolution selects the correct conversion based
377		// on the Endpoint type.
378		//----------------------------------------------------------
379
380		/** Convert sockaddr_storage to an IP endpoint (tag overload).
381
382		@param storage The sockaddr_storage with fields in network byte order.
383		@param len The address length returned by the kernel.
384		@return An endpoint with address and port extracted from storage.
385		*/
386		inline endpoint
387	27214x	from_sockaddr_as(
388		sockaddr_storage const& storage,
389		socklen_t /len/,
390		endpoint const&) noexcept
391		{
392	27214x	return from_sockaddr(storage);
393		}
394
395		/** Convert sockaddr_storage to a local_endpoint (tag overload).
396
397		@param storage The sockaddr_storage.
398		@param len The address length returned by the kernel.
399		@return A local_endpoint with path extracted from storage.
400		*/
401		inline local_endpoint
402	946x	from_sockaddr_as(
403		sockaddr_storage const& storage,
404		socklen_t len,
405		local_endpoint const&) noexcept
406		{
407	946x	return from_sockaddr_local(storage, len);
408		}
409
410		} // namespace boost::corosio::detail
411
412		#endif
413