add playground_socket

.gitignore

@@ -10,6 +10,7 @@
 !www
 !includes
 !test
+!playground
 
 !*.cpp
 !*.hpp

playground/.gitignore

@@ -0,0 +1,5 @@
+*
+
+!.gitignore
+!*.cpp
+!*.hpp

playground/playground_socket.cpp

@@ -0,0 +1,69 @@
+#include <fcntl.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <cerrno>
+#include <cstring>
+#include <string>
+#include <iostream>
+
+int test_socket(const char *server_ip, const char *server_port) {
+	int errcode;
+	int socket_fd;
+	int ai_family, ai_socktype, ai_protocol;
+	struct addrinfo *addr_info;
+	struct addrinfo	hints = {};
+//	const char *server_ip = "127.0.0.1";
+//	const char *server_port = "65536";
+
+	printf("ip:%s, port:%s\n", server_ip, server_port);
+
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_family = AF_UNSPEC;  // allows IPv4 and IPv6
+	hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST | AI_NUMERICSERV;  // socket, IP, PORT
+	hints.ai_protocol = IPPROTO_TCP;
+
+	errcode = getaddrinfo(server_ip, server_port, &hints, &addr_info);
+	if (errcode != 0) {
+		std::cerr << "[Error] getaddrinfo:" << gai_strerror(errcode) << std::endl;
+		return 1;
+	}
+//	std::cout << "errcode:" << errcode << ", " <<
+
+	ai_family = addr_info->ai_family;
+	ai_socktype = addr_info->ai_socktype;
+	ai_protocol = addr_info->ai_protocol;
+	errno = 0;
+	std::cout << "socket" << std::endl;
+	socket_fd = socket(ai_family, ai_socktype, ai_protocol);
+	if (socket_fd == -1) {
+		std::cerr << "[Error] socket:" << strerror(errno) << std::endl;
+		return 1;
+	}
+
+	std::cout << "bind" << std::endl;
+	errno = 0;
+	if (bind(socket_fd, addr_info->ai_addr, addr_info->ai_addrlen) == -1) {
+		std::cerr << "[Error] bind:" << strerror(errno) << std::endl;
+		return 1;
+	}
+
+	std::cout << "listen" << std::endl;
+	if (listen(socket_fd, SOMAXCONN) == -1) {
+		std::cerr << "[Error] listen:" << strerror(errno) << std::endl;
+		return 1;
+	}
+
+	std::cout << "OK" << std::endl;
+	return 0;
+}
+
+// port 0, 0はエラーにならない
+int main() {
+	int ret1 = test_socket("255.255.255.254", "8080");
+	int ret2 = test_socket("255.255.255.254", "8080");
+
+	std::cout << "ret1:" << ret1 << std::endl;
+	std::cout << "ret2:" << ret2 << std::endl;
+}