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_DETAIL_ENDPOINT_CONVERT_HPP
 
11 - 
#define BOOST_COROSIO_DETAIL_ENDPOINT_CONVERT_HPP
 
12 -
 
13 - 
#include <boost/corosio/endpoint.hpp>
 
14 - 
#include <boost/corosio/detail/platform.hpp>
 
15 -
 
16 - 
#include <cstring>
 
17 -
 
18 - 
#if BOOST_COROSIO_POSIX
 
19 - 
#include <sys/socket.h>
 
20 - 
#include <netinet/in.h>
 
21 - 
#include <arpa/inet.h>
 
22 - 
#else
 
23 - 
#ifndef WIN32_LEAN_AND_MEAN
 
24 - 
#define WIN32_LEAN_AND_MEAN
 
25 - 
#endif
 
26 - 
#ifndef NOMINMAX
 
27 - 
#define NOMINMAX
 
28 - 
#endif
 
29 - 
#include <WinSock2.h>
 
30 - 
#include <Ws2tcpip.h>
 
31 - 
#endif
 
32 -
 
33 - 
namespace boost::corosio::detail {
 
34 -
 
35 - 
/** Convert IPv4 endpoint to sockaddr_in.
 
36 -
 
37 - 
    @param ep The endpoint to convert. Must be IPv4 (is_v4() == true).
 
38 - 
    @return A sockaddr_in structure with fields in network byte order.
 
39 - 
*/
 
40 - 
inline sockaddr_in
 
41 - 
to_sockaddr_in(endpoint const& ep) noexcept
 
42 - 
{
 
43 - 
    sockaddr_in sa{};
 
44 - 
    sa.sin_family = AF_INET;
 
45 - 
    sa.sin_port   = htons(ep.port());
 
46 - 
    auto bytes    = ep.v4_address().to_bytes();
 
47 - 
    std::memcpy(&sa.sin_addr, bytes.data(), 4);
 
48 - 
    return sa;
 
49 - 
}
 
50 -
 
51 - 
/** Convert IPv6 endpoint to sockaddr_in6.
 
52 -
 
53 - 
    @param ep The endpoint to convert. Must be IPv6 (is_v6() == true).
 
54 - 
    @return A sockaddr_in6 structure with fields in network byte order.
 
55 - 
*/
 
56 - 
inline sockaddr_in6
 
57 - 
to_sockaddr_in6(endpoint const& ep) noexcept
 
58 - 
{
 
59 - 
    sockaddr_in6 sa{};
 
60 - 
    sa.sin6_family = AF_INET6;
 
61 - 
    sa.sin6_port   = htons(ep.port());
 
62 - 
    auto bytes     = ep.v6_address().to_bytes();
 
63 - 
    std::memcpy(&sa.sin6_addr, bytes.data(), 16);
 
64 - 
    return sa;
 
65 - 
}
 
66 -
 
67 - 
/** Create endpoint from sockaddr_in.
 
68 -
 
69 - 
    @param sa The sockaddr_in structure with fields in network byte order.
 
70 - 
    @return An endpoint with address and port extracted from sa.
 
71 - 
*/
 
72 - 
inline endpoint
 
73 - 
from_sockaddr_in(sockaddr_in const& sa) noexcept
 
74 - 
{
 
75 - 
    ipv4_address::bytes_type bytes;
 
76 - 
    std::memcpy(bytes.data(), &sa.sin_addr, 4);
 
77 - 
    return endpoint(ipv4_address(bytes), ntohs(sa.sin_port));
 
78 - 
}
 
79 -
 
80 - 
/** Create endpoint from sockaddr_in6.
 
81 -
 
82 - 
    @param sa The sockaddr_in6 structure with fields in network byte order.
 
83 - 
    @return An endpoint with address and port extracted from sa.
 
84 - 
*/
 
85 - 
inline endpoint
 
86 - 
from_sockaddr_in6(sockaddr_in6 const& sa) noexcept
 
87 - 
{
 
88 - 
    ipv6_address::bytes_type bytes;
 
89 - 
    std::memcpy(bytes.data(), &sa.sin6_addr, 16);
 
90 - 
    return endpoint(ipv6_address(bytes), ntohs(sa.sin6_port));
 
91 - 
}
 
92 -
 
93 - 
/** Convert an IPv4 endpoint to an IPv4-mapped IPv6 sockaddr_in6.
 
94 -
 
95 - 
    Produces a `sockaddr_in6` with the `::ffff:` prefix, suitable
 
96 - 
    for passing an IPv4 destination to a dual-stack IPv6 socket.
 
97 -
 
98 - 
    @param ep The endpoint to convert. Must be IPv4 (is_v4() == true).
 
99 - 
    @return A sockaddr_in6 with the IPv4-mapped address.
 
100 - 
*/
 
101 - 
inline sockaddr_in6
 
102 - 
to_v4_mapped_sockaddr_in6(endpoint const& ep) noexcept
 
103 - 
{
 
104 - 
    sockaddr_in6 sa{};
 
105 - 
    sa.sin6_family = AF_INET6;
 
106 - 
    sa.sin6_port   = htons(ep.port());
 
107 - 
    // ::ffff:0:0/96 prefix
 
108 - 
    sa.sin6_addr.s6_addr[10] = 0xff;
 
109 - 
    sa.sin6_addr.s6_addr[11] = 0xff;
 
110 - 
    auto bytes = ep.v4_address().to_bytes();
 
111 - 
    std::memcpy(&sa.sin6_addr.s6_addr[12], bytes.data(), 4);
 
112 - 
    return sa;
 
113 - 
}
 
114 -
 
115 - 
/** Convert endpoint to sockaddr_storage.
 
116 -
 
117 - 
    Dispatches to @ref to_sockaddr_in or @ref to_sockaddr_in6
 
118 - 
    based on the endpoint's address family.
 
119 -
 
120 - 
    @param ep The endpoint to convert.
 
121 - 
    @param storage Output parameter filled with the sockaddr.
 
122 - 
    @return The length of the filled sockaddr structure.
 
123 - 
*/
 
124 - 
inline socklen_t
 
125 - 
to_sockaddr( endpoint const& ep, sockaddr_storage& storage ) noexcept
 
126 - 
{
 
127 - 
    std::memset( &storage, 0, sizeof( storage ) );
 
128 - 
    if( ep.is_v4() )
 
129 - 
    {
 
130 - 
        auto sa = to_sockaddr_in( ep );
 
131 - 
        std::memcpy( &storage, &sa, sizeof( sa ) );
 
132 - 
        return sizeof( sa );
 
133 - 
    }
 
134 - 
    auto sa6 = to_sockaddr_in6( ep );
 
135 - 
    std::memcpy( &storage, &sa6, sizeof( sa6 ) );
 
136 - 
    return sizeof( sa6 );
 
137 - 
}
 
138 -
 
139 - 
/** Convert endpoint to sockaddr_storage for a specific socket family.
 
140 -
 
141 - 
    When the socket is AF_INET6 and the endpoint is IPv4, the address
 
142 - 
    is converted to an IPv4-mapped IPv6 address (`::ffff:x.x.x.x`) so
 
143 - 
    dual-stack sockets can connect to IPv4 destinations.
 
144 -
 
145 - 
    @param ep The endpoint to convert.
 
146 - 
    @param socket_family The address family of the socket (AF_INET or
 
147 - 
        AF_INET6).
 
148 - 
    @param storage Output parameter filled with the sockaddr.
 
149 - 
    @return The length of the filled sockaddr structure.
 
150 - 
*/
 
151 - 
inline socklen_t
 
152 - 
to_sockaddr(
 
153 - 
    endpoint const& ep,
 
154 - 
    int socket_family,
 
155 - 
    sockaddr_storage& storage) noexcept
 
156 - 
{
 
157 - 
    // IPv4 endpoint on IPv6 socket: use IPv4-mapped address
 
158 - 
    if (ep.is_v4() && socket_family == AF_INET6)
 
159 - 
    {
 
160 - 
        std::memset(&storage, 0, sizeof(storage));
 
161 - 
        auto sa6 = to_v4_mapped_sockaddr_in6(ep);
 
162 - 
        std::memcpy(&storage, &sa6, sizeof(sa6));
 
163 - 
        return sizeof(sa6);
 
164 - 
    }
 
165 - 
    return to_sockaddr(ep, storage);
 
166 - 
}
 
167 -
 
168 - 
/** Create endpoint from sockaddr_storage.
 
169 -
 
170 - 
    Dispatches on `ss_family` to reconstruct the appropriate
 
171 - 
    IPv4 or IPv6 endpoint.
 
172 -
 
173 - 
    @param storage The sockaddr_storage with fields in network byte order.
 
174 - 
    @return An endpoint with address and port extracted from storage.
 
175 - 
*/
 
176 - 
inline endpoint
 
177 - 
from_sockaddr( sockaddr_storage const& storage ) noexcept
 
178 - 
{
 
179 - 
    if( storage.ss_family == AF_INET )
 
180 - 
    {
 
181 - 
        sockaddr_in sa;
 
182 - 
        std::memcpy( &sa, &storage, sizeof( sa ) );
 
183 - 
        return from_sockaddr_in( sa );
 
184 - 
    }
 
185 - 
    if( storage.ss_family == AF_INET6 )
 
186 - 
    {
 
187 - 
        sockaddr_in6 sa6;
 
188 - 
        std::memcpy( &sa6, &storage, sizeof( sa6 ) );
 
189 - 
        return from_sockaddr_in6( sa6 );
 
190 - 
    }
 
191 - 
    return endpoint{};
 
192 - 
}
 
193 -
 
194 - 
/** Return the native address family for an endpoint.
 
195 -
 
196 - 
    @param ep The endpoint to query.
 
197 - 
    @return `AF_INET` for IPv4, `AF_INET6` for IPv6.
 
198 - 
*/
 
199 - 
inline int
 
200 - 
endpoint_family( endpoint const& ep ) noexcept
 
201 - 
{
 
202 - 
    return ep.is_v6() ? AF_INET6 : AF_INET;
 
203 - 
}
 
204 -
 
205 - 
/** Return the address family of a socket descriptor.
 
206 -
 
207 - 
    @param fd The socket file descriptor.
 
208 - 
    @return AF_INET, AF_INET6, or AF_UNSPEC on failure.
 
209 - 
*/
 
210 - 
inline int
 
211 - 
socket_family(
 
212 - 
#if BOOST_COROSIO_POSIX
 
213 - 
    int fd
 
214 - 
#else
 
215 - 
    std::uintptr_t fd
 
216 - 
#endif
 
217 - 
    ) noexcept
 
218 - 
{
 
219 - 
    sockaddr_storage storage{};
 
220 - 
    socklen_t len = sizeof(storage);
 
221 - 
    if (getsockname(
 
222 - 
#if BOOST_COROSIO_POSIX
 
223 - 
            fd,
 
224 - 
#else
 
225 - 
            static_cast<SOCKET>(fd),
 
226 - 
#endif
 
227 - 
            reinterpret_cast<sockaddr*>(&storage), &len) != 0)
 
228 - 
        return AF_UNSPEC;
 
229 - 
    return storage.ss_family;
 
230 - 
}
 
231 -
 
232 - 
} // namespace boost::corosio::detail
 
233 -
 
234 - 
#endif