UNIX网络编程练习-获取客户端IP和端口

// 服务端程序
// DATE: 2015.11.30
// AUTH: robertkun

#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <unistd.h>
#include <errno.h>

using namespace std;

typedef struct sockaddr SA;

int main()
{
	char buff[256] = {0};

	// 创建TCP套接字
	int _fd = socket(AF_INET, SOCK_STREAM, 0);
	
	// 绑定端口到套接字
	struct sockaddr_in addr;
	bzero(&addr, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(6543);
	
	if(bind(_fd, (SA *)&addr, sizeof(addr)) != 0) {
		cerr<<"bind error!"<<errno<<endl;
		return -1;
	}

	// 打开监听
	if(listen(_fd, 256) != 0) {
		cerr<<"listen error!"<<endl;
		return -1;
	}

	// 等待连接
	while(1)
	{
		struct sockaddr_in c_addr;
		socklen_t c_len = sizeof(c_addr); // 这里必须初始化,才可以使用
		int _connfd = accept(_fd, (SA *)&c_addr, &c_len);
		if(_connfd) {
			// 获取客户端信息,也可以使用getpeername()函数
			//getpeername(_connfd, (SA *)&c_addr, &c_len);

			cout<<"accept ok! "<<"client = "<<inet_ntoa(c_addr.sin_addr)
			<<":"<<ntohs(c_addr.sin_port)<<endl;
		}

		time_t ticks = time(NULL);
		snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks));
		write(_connfd, buff, strlen(buff));
	
		// 终止连接
		close(_connfd);
	}

	return 0;
}

输出:



man accept:

The addrlen argument is a value-result argument:

the caller must initialize it to contain the size (in bytes) of the structure pointed to by addr;

on return it will contain the actual size of the peer address.