90 lines
2.2 KiB
C++
90 lines
2.2 KiB
C++
/*
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* IXGetFreePort.cpp
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* Author: Benjamin Sergeant
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* Copyright (c) 2019 Machine Zone. All rights reserved.
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*/
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#include "IXGetFreePort.h"
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#include <ixwebsocket/IXNetSystem.h>
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#include <ixwebsocket/IXSocket.h>
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#include <random>
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#include <string>
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namespace ix
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{
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int getAnyFreePortRandom()
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{
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std::random_device rd;
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std::uniform_int_distribution<int> dist(1024 + 1, 65535);
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return dist(rd);
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}
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int getAnyFreePort()
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{
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int sockfd;
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if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
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{
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return getAnyFreePortRandom();
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}
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int enable = 1;
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if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char*) &enable, sizeof(enable)) < 0)
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{
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return getAnyFreePortRandom();
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}
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// Bind to port 0. This is the standard way to get a free port.
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struct sockaddr_in server; // server address information
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server.sin_family = AF_INET;
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server.sin_port = htons(0);
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server.sin_addr.s_addr = inet_addr("127.0.0.1");
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if (bind(sockfd, (struct sockaddr*) &server, sizeof(server)) < 0)
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{
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Socket::closeSocket(sockfd);
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return getAnyFreePortRandom();
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}
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struct sockaddr_in sa; // server address information
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socklen_t len = sizeof(sa);
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if (getsockname(sockfd, (struct sockaddr*) &sa, &len) < 0)
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{
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Socket::closeSocket(sockfd);
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return getAnyFreePortRandom();
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}
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int port = ntohs(sa.sin_port);
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Socket::closeSocket(sockfd);
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return port;
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}
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int getFreePort()
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{
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while (true)
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{
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#if defined(__has_feature)
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#if __has_feature(address_sanitizer)
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int port = getAnyFreePortRandom();
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#else
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int port = getAnyFreePort();
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#endif
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#else
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int port = getAnyFreePort();
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#endif
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//
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// Only port above 1024 can be used by non root users, but for some
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// reason I got port 7 returned with macOS when binding on port 0...
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//
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if (port > 1024)
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{
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return port;
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}
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}
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return -1;
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}
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} // namespace ix
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