147 lines
3.9 KiB
C++
147 lines
3.9 KiB
C++
// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
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// Distributed under the MIT License (http://opensource.org/licenses/MIT)
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#pragma once
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#ifdef _WIN32
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# error include tcp_client-windows.h instead
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#endif
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// tcp client helper
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#include <spdlog/common.h>
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#include <spdlog/details/os.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <unistd.h>
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#include <netdb.h>
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#include <netinet/tcp.h>
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#include <netinet/in.h>
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#include <string>
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namespace spdlog {
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namespace details {
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class tcp_client
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{
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int socket_ = -1;
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public:
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bool is_connected() const
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{
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return socket_ != -1;
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}
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void close()
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{
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if (is_connected())
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{
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::close(socket_);
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socket_ = -1;
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}
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}
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int fd() const
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{
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return socket_;
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}
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~tcp_client()
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{
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close();
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}
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// try to connect or throw on failure
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void connect(const std::string &host, int port)
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{
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close();
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struct addrinfo hints
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{};
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memset(&hints, 0, sizeof(struct addrinfo));
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hints.ai_family = AF_UNSPEC; // To work with IPv4, IPv6, and so on
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hints.ai_socktype = SOCK_STREAM; // TCP
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hints.ai_flags = AI_NUMERICSERV; // port passed as as numeric value
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hints.ai_protocol = 0;
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auto port_str = std::to_string(port);
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struct addrinfo *addrinfo_result;
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auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
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if (rv != 0)
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{
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throw_spdlog_ex(fmt_lib::format("::getaddrinfo failed: {}", gai_strerror(rv)));
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}
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// Try each address until we successfully connect(2).
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int last_errno = 0;
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for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next)
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{
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#if defined(SOCK_CLOEXEC)
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const int flags = SOCK_CLOEXEC;
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#else
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const int flags = 0;
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#endif
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socket_ = ::socket(rp->ai_family, rp->ai_socktype | flags, rp->ai_protocol);
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if (socket_ == -1)
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{
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last_errno = errno;
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continue;
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}
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rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
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if (rv == 0)
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{
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break;
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}
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last_errno = errno;
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::close(socket_);
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socket_ = -1;
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}
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::freeaddrinfo(addrinfo_result);
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if (socket_ == -1)
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{
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throw_spdlog_ex("::connect failed", last_errno);
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}
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// set TCP_NODELAY
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int enable_flag = 1;
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::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag), sizeof(enable_flag));
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// prevent sigpipe on systems where MSG_NOSIGNAL is not available
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#if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
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::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, reinterpret_cast<char *>(&enable_flag), sizeof(enable_flag));
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#endif
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#if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
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# error "tcp_sink would raise SIGPIPE since neither SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
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#endif
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}
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// Send exactly n_bytes of the given data.
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// On error close the connection and throw.
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void send(const char *data, size_t n_bytes)
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{
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size_t bytes_sent = 0;
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while (bytes_sent < n_bytes)
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{
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#if defined(MSG_NOSIGNAL)
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const int send_flags = MSG_NOSIGNAL;
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#else
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const int send_flags = 0;
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#endif
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auto write_result = ::send(socket_, data + bytes_sent, n_bytes - bytes_sent, send_flags);
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if (write_result < 0)
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{
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close();
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throw_spdlog_ex("write(2) failed", errno);
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}
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if (write_result == 0) // (probably should not happen but in any case..)
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{
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break;
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}
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bytes_sent += static_cast<size_t>(write_result);
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}
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}
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};
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} // namespace details
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} // namespace spdlog
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