c - TCP 服务器套接字未通过 addrinfo 方法侦听
问题描述
所以这里是代码,代码成功编译......
#include <stdio.h> // for printf
#include <linux/if_tun.h> //for IFF_TUN
#include <sys/socket.h> //socket, struct sockaddr_in
#include <fcntl.h> // for O_RDWR macros
#include <string.h> //for strcpy
#include <unistd.h> //for read();
#include <netdb.h> //for struct sockaddr
#include <net/if.h> //struct ifreq and IFNAMSIZ and other macros
#include <errno.h>
#include <stdlib.h>
// _check: error handler
static int _check(int retval, const char *msg)
{
if(retval == -1)
{
fprintf(stderr, "%s: %s\n", msg, strerror(errno));
exit(EXIT_FAILURE);
}
return retval;
}
int tcp_listen_sock(int listen_connection)
{
/*-------------------------socket-----------------------*/
int sock, tcp_sock;
struct addrinfo hints, *result;
struct sockaddr *addrin;
memset(&hints ,0 , sizeof(hints));
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
const char *host;
host = "0.0.0.0";
_check(getaddrinfo(host, NULL, &hints, &result), "getaddrinfo");
if (result->ai_family == AF_INET)
((struct sockaddr_in *)result->ai_addr)->sin_port = htons(5678);
else if (result->ai_family == AF_INET6)
((struct sockaddr_in6 *)result->ai_addr)->sin6_port = htons(5678);
else {
fprintf(stderr, "unknown ai_family %d", result->ai_family);
freeaddrinfo(result);
return -1;
}
memcpy(addrin, result->ai_addr, result->ai_addrlen);
// *client_len = result->ai_addrlen;
_check((sock = socket(AF_INET, SOCK_STREAM, 0)), "socket");
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "enp0s3");
_check(setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr)), "setsockopt");
int flags;
if((flags = fcntl(sock, F_GETFL)) != -1)
{
fcntl(sock, F_SETFL, flags | O_NONBLOCK);
}
else
perror("socket fcntl");
_check(bind(sock,result->ai_addr, result->ai_addrlen), "tcp bind");
int len = sizeof(struct sockaddr);
_check(listen(sock, listen_connection), "listen");
tcp_sock = accept(sock, result->ai_addr, &result->ai_addrlen );
printf("now listening on tcp!\n");
return tcp_sock;
}
int main(int argc, char **argv)
{
printf("Starting program\n");
int tcp = tcp_listen_sock(5);
printf("ending program\n");
return 0;
}
和 ,
输出
Starting program
now listening on tcp!
ending program
但服务器套接字实际上并没有在听......
预期输出:
Starting program
now listening on tcp!
read...
write...
read...
write...
read...
write..
我无法弄清楚我缺少什么,我知道我还没有实现读、写,但是当服务器套接字似乎工作正常并正常监听时我会这样做。
注意:我在 linux 中执行此操作(特别是 ubuntu)
任何帮助将不胜感激...
解决方案
调用 getaddrinfo 来初始化本地列表套接字似乎有点过头了。
从这个开始。这是一个简单的“创建侦听套接字并等待传入的 TCP 连接”代码示例。
int tcp_socket_listen(int listen_connection)
{
struct sockaddr_in addr = {0};
sockaddr_in addrRemote = {0};
socklen_t sizeRemote = 0;
int tcp_socket = -1;
s = socket(AF_INET, SOCK_STREAM, 0);
_check(s, "socket");
addr.sin_family = AF_INET;
addr.sin_port = htons(5678);
_check(bind(s, (sockaddr*)&addr, sizeof(addr)), "bind");
_check(listen(sock, listen_connection), "listen");
sizeRemote = sizeof(addrRemote);
tcp_sock = accept(s, (sockaddr*)&addrRemote, &sizeRemote);
_check(tcp_sock, "accept");
printf("now listening on TCP\n");
return tcp_sock;
}
现在,如果您想绑定到特定适配器(例如“enp0s3”)而不是默认适配器(“所有适配器”)或需要 IPV6 支持,您可以在此处仔细阅读我在 github 上的示例代码,GetSocketAddressForAdapter
并将该地址用于bind
调用上面的默认addr
地址。它是 C++,但您可以通过一些工作将其移植到直接 C。