网络编程套接字（二）之UDP服务器简单实现 - ToB企服应用市场:ToB评测及商务社交产业平台

NAME
socket - create an endpoint for communication
SYNOPSIS
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
int socket(int domain, int type, int protocol);

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NAME
bind - bind a name to a socket
SYNOPSIS
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
int bind(int sockfd, const struct sockaddr *addr,
socklen_t addrlen);

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#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
in_addr_t inet_addr(const char *cp);
char *inet_ntoa(struct in_addr in);

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NAME
recv, recvfrom, recvmsg - receive a message from a socket
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
ssize_t recv(int sockfd, void *buf, size_t len, int flags);
ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags,
struct sockaddr *src_addr, socklen_t *addrlen);
ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);

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NAME
send, sendto, sendmsg - send a message on a socket
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
ssize_t send(int sockfd, const void *buf, size_t len, int flags);
ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen);
ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);

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#include <iostream>
#include "udp_server.hpp"
#include <string>
#include <memory>
static void usage(const std::string &proc)
{
std::cout << "\nusage: " << proc << " port\n" << std::endl;
}
// ./udpserver port
int main(int argc, char *argv[])
{
if (argc != 2)
{
usage(argv[0]);
exit(0);
}
uint16_t port = atoi(argv[1]);
std::unique_ptr<UdpServer> usvr(new UdpServer(port));
usvr->InitServer();
usvr->start();
return 0;
}

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#pragma once
#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <string>
class UdpServer
{
public:
UdpServer(const uint16_t &port, std::string ip = "")
: ip_(ip), port_(port), sock_(-1)
{
}
void InitServer()
{
// 1.创建套接字
sock_ = socket(AF_INET, SOCK_DGRAM, 0);
if (sock_ < 0)
{
std::cerr << "创建套接字失败！" << errno << strerror(errno) << std::endl;
exit(0);
}
// 2.进行绑定:绑定ip和端口号
// 2.1 服务器的套接字填充结构
struct sockaddr_in local_server;
bzero(&local_server, sizeof(local_server));
local_server.sin_family = AF_INET;
local_server.sin_port = htons(port_); // 端口号需要从主机转网络
local_server.sin_addr.s_addr = ip_.empty() ? INADDR_ANY : inet_addr(ip_.c_str()); // ip地址需要主机转网络，并且要转化成4字节形式
int len = sizeof(local_server);
if (bind(sock_, (struct sockaddr *)&local_server, len))
{
std::cout << "绑定失败！" << errno << strerror(errno) << std::endl;
exit(1);
}
std::cout << "服务器初始化完成！" << std::endl;
}
void start()
{
std::cout << "服务器运行成功!" << std::endl;
char buffer[1024];
char result[1024];
std::string server_echo;
// 服务器不能停下来，除非挂掉——死循环
for (;;)
{
struct sockaddr_in src_client; // 服务器收到的客户端来源
socklen_t len = sizeof(src_client);
ssize_t s = recvfrom(sock_, buffer, sizeof(buffer) - 1, 0, (struct sockaddr *)&src_client, &len);
if (s < 0)
{
std::cout << "接收消息失败！" << std::endl;
}
buffer[s] = 0;
//std::string src_client_ip = inet_ntoa(src_client.sin_addr);
//uint16_t src_client_port = ntohs(src_client.sin_port);
//std::cout << "[" << src_client_ip << "," << src_client_port << "]: " << buffer << std::endl;
// 客户端发过来的信息是指令，服务器将结果返回给客户端
FILE *fp = popen(buffer, "r");
if (fp == nullptr)
{
std::cout << "popen失败!" << std::endl;
continue;
}
while (fgets(result, sizeof(result), fp) != nullptr)
{
server_echo += result;
}
// 服务器发回消息
sendto(sock_, server_echo.c_str(), server_echo.size(), 0, (struct sockaddr *)&src_client, len);
//sendto(sock_, buffer, sizeof(buffer), 0, (struct sockaddr *)&src_client, len);
}
}
private:
std::string ip_; // 服务器ip地址
uint16_t port_; // 服务器端口号
int sock_; // 套接字
};

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#include <iostream>
#include "udp_server.hpp"
#include <string>
#include <memory>
static void usage(const std::string &proc)
{
std::cout << "\nusage: " << proc << " port\n" << std::endl;
}
// ./udpserver port
int main(int argc, char *argv[])
{
if (argc != 2)
{
usage(argv[0]);
exit(0);
}
uint16_t port = atoi(argv[1]);
std::unique_ptr<UdpServer> usvr(new UdpServer(port));
usvr->InitServer();
usvr->start();
return 0;
}

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#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <cerrno>
#include <unistd.h>
#include <string>
#include <stdio.h>
#include <cstring>
static void usage(const std::string &proc)
{
std::cout << "\nusage: "
<< proc << " port ip\n"
<< std::endl;
}
// ./udpclient ip port 带上服务器的ip和端口号
int main(int argc, char *argv[])
{
if (argc != 3)
{
usage(argv[0]);
exit(0);
}
// 1.创建套接字
int sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0)
{
std::cerr << "创建套接字失败！" << errno << strerror(errno) << std::endl;
exit(1);
}
// 作为客户端，其不需要进行绑定，由os自动进行绑定
std::string message;
// 给哪个服务器发送消息，填充服务器信息
struct sockaddr_in send_server;
bzero(&send_server, sizeof(send_server));
send_server.sin_family = AF_INET;
send_server.sin_port = htons(atoi(argv[2]));
send_server.sin_addr.s_addr = inet_addr(argv[1]);
while (true)
{
// 2.从键盘获取信息
std::cout << "请输入#";
std::getline(std::cin, message);
if (message == "quit")
break;
// 3.发送消息
sendto(sock, message.c_str(), message.size(), 0, (struct sockaddr *)&send_server, sizeof(send_server));
// 4.接收服务器的消息
char buffer[1024];
struct sockaddr_in revc_server;
bzero(&revc_server, sizeof(revc_server));
socklen_t len = sizeof(revc_server);
ssize_t s = recvfrom(sock, buffer, sizeof(buffer) - 1, 0, (struct sockaddr *)&revc_server, &len);
std::cout << "服务器说：" << buffer << std::endl;
}
close(sock);
return 0;
}

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