TLA Line data Source code
1 : //
2 : // Copyright (c) 2026 Michael Vandeberg
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_EPOLL_EPOLL_TRAITS_HPP
11 : #define BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_TRAITS_HPP
12 :
13 : #include <boost/corosio/detail/platform.hpp>
14 :
15 : #if BOOST_COROSIO_HAS_EPOLL
16 :
17 : #include <boost/corosio/native/detail/make_err.hpp>
18 : #include <boost/corosio/native/detail/reactor/reactor_descriptor_state.hpp>
19 :
20 : #include <system_error>
21 : #include <tuple>
22 :
23 : #include <errno.h>
24 : #include <netinet/in.h>
25 : #include <sys/socket.h>
26 :
27 : /* epoll backend traits.
28 :
29 : Captures the platform-specific behavior of the Linux epoll backend:
30 : atomic SOCK_NONBLOCK|SOCK_CLOEXEC on socket(), accept4() for
31 : accepted connections, and sendmsg(MSG_NOSIGNAL) for writes.
32 : */
33 :
34 : namespace boost::corosio::detail {
35 :
36 : class epoll_scheduler;
37 :
38 : struct epoll_traits
39 : {
40 : using scheduler_type = epoll_scheduler;
41 : using desc_state_type = reactor_descriptor_state;
42 :
43 : static constexpr bool needs_write_notification = false;
44 :
45 : // No extra per-socket state or lifecycle hooks needed for epoll.
46 : struct stream_socket_hook
47 : {
48 HIT 155 : std::error_code on_set_option(
49 : int fd, int level, int optname,
50 : void const* data, std::size_t size) noexcept
51 : {
52 155 : if (::setsockopt(
53 : fd, level, optname, data,
54 155 : static_cast<socklen_t>(size)) != 0)
55 2 : return make_err(errno);
56 153 : return {};
57 : }
58 34251 : static void pre_shutdown(int) noexcept {}
59 11297 : static void pre_destroy(int) noexcept {}
60 : };
61 :
62 : struct write_policy
63 : {
64 71 : static ssize_t write(int fd, iovec* iovecs, int count) noexcept
65 : {
66 71 : msghdr msg{};
67 71 : msg.msg_iov = iovecs;
68 71 : msg.msg_iovlen = static_cast<std::size_t>(count);
69 :
70 : ssize_t n;
71 : do
72 : {
73 71 : n = ::sendmsg(fd, &msg, MSG_NOSIGNAL);
74 : }
75 71 : while (n < 0 && errno == EINTR);
76 71 : return n;
77 : }
78 :
79 168736 : static ssize_t write_one(
80 : int fd, void const* data, std::size_t size) noexcept
81 : {
82 : ssize_t n;
83 : do
84 : {
85 168736 : n = ::send(fd, data, size, MSG_NOSIGNAL);
86 : }
87 168736 : while (n < 0 && errno == EINTR);
88 168736 : return n;
89 : }
90 : };
91 :
92 : struct accept_policy
93 : {
94 7464 : static int do_accept(
95 : int fd, sockaddr_storage& peer, socklen_t& addrlen) noexcept
96 : {
97 7464 : addrlen = sizeof(peer);
98 : int new_fd;
99 : do
100 : {
101 7464 : new_fd = ::accept4(
102 : fd, reinterpret_cast<sockaddr*>(&peer), &addrlen,
103 : SOCK_NONBLOCK | SOCK_CLOEXEC);
104 : }
105 7464 : while (new_fd < 0 && errno == EINTR);
106 7464 : return new_fd;
107 : }
108 : };
109 :
110 : // Create a nonblocking, close-on-exec socket using Linux's atomic flags.
111 4223 : static int create_socket(int family, int type, int protocol) noexcept
112 : {
113 4223 : return ::socket(family, type | SOCK_NONBLOCK | SOCK_CLOEXEC, protocol);
114 : }
115 :
116 : // Apply protocol-specific options after socket creation.
117 : // For IP sockets, sets IPV6_V6ONLY on AF_INET6 (best-effort).
118 : static std::error_code
119 3881 : configure_ip_socket(int fd, int family) noexcept
120 : {
121 3881 : if (family == AF_INET6)
122 : {
123 21 : int one = 1;
124 42 : std::ignore = ::setsockopt(
125 21 : fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
126 : }
127 3881 : return {};
128 : }
129 :
130 : // Apply protocol-specific options for acceptor sockets.
131 : // For IP acceptors, sets IPV6_V6ONLY=0 (dual-stack, best-effort).
132 : static std::error_code
133 246 : configure_ip_acceptor(int fd, int family) noexcept
134 : {
135 246 : if (family == AF_INET6)
136 : {
137 11 : int val = 0;
138 22 : std::ignore = ::setsockopt(
139 11 : fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
140 : }
141 246 : return {};
142 : }
143 :
144 : // No extra configuration needed for local (unix) sockets on epoll.
145 : static std::error_code
146 96 : configure_local_socket(int /*fd*/) noexcept
147 : {
148 96 : return {};
149 : }
150 :
151 : // Non-mutating validation for fds adopted via assign(). Used when
152 : // the caller retains fd ownership responsibility.
153 : static std::error_code
154 120 : validate_assigned_fd(int /*fd*/) noexcept
155 : {
156 120 : return {};
157 : }
158 : };
159 :
160 : } // namespace boost::corosio::detail
161 :
162 : #endif // BOOST_COROSIO_HAS_EPOLL
163 :
164 : #endif // BOOST_COROSIO_NATIVE_DETAIL_EPOLL_EPOLL_TRAITS_HPP
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