linux 下socket编程 一对一阻塞通信

linux下socket编程，socket的流程和windows几乎一样，只是linux下不需要加载socket版本号。

1.create socket。

函数：int server_socket = socket(AF_INET, SOCK_STREAM, 0);

第一个参数：通信域    可选：AF_INET是IPV4， AF_INET6是IPV6

第二个参数： 通信类型 可选：SOCK_STREAM(面向连接可靠TCP），SOCK_DGRAM(无连接不可靠UDP)

第三个参数： 使用协议，和第二个参数对应，一般为0(依据第二个参数自动补充协议), IPPROTO_TCP(TCP), IPPROTO_UDP(UDP)

返回值为-1失败，否则成功

2.bind socket 

首先创建本地地址

    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(12345);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    bzero(&(server_addr.sin_zero), 8);   //补齐

 int bind_result = bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr));

返回值为-1则失败，否则成功

3.listen   

listen(server_socket, 5)  // 5为最多可以同时连接的客户端

返回值-1失败，否则成功

4.accept

struct sockaddr_in client_address;

socklen_t address_len;

int client_socket = accept(server_socket, (struct sockaddr *)&client_address, &address_len);

client_addres得到客户端地址

返回值大于0成功，否则失败

5.recv

recv(client_socket, recv_msg, BUFFER_SIZE, 0);

返回值大于0，表示接受到的字节长度；等于0，表示客户端退出；小于0，表示接收消息失败(如网络不好)

6.send

send(client_socket, input_msg, BUFFER_SIZE, 0);

服务器端代码：

#include<stdio.h>#include<netinet/in.h>#include<sys/socket.h>#include<arpa/inet.h>#include<string.h>int main(int argc, const char * argv[]){    struct sockaddr_in server_addr;    server_addr.sin_family = AF_INET;    server_addr.sin_port = htons(11332);    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");    bzero(&(server_addr.sin_zero), 8);    int server_socket = socket(AF_INET, SOCK_STREAM, 0);    if(server_socket == -1)    {perror("socket error");        return 1;    }    int bind_result = bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr));    if(bind_result == -1)    {perror("bind error");return -1;    }    if(listen(server_socket, 5) == -1)    {perror("listen error");return -1;    }    struct sockaddr_in client_address;    socklen_t address_len;    int client_socket = accept(server_socket, (struct sockaddr *)&client_address, &address_len);    if(client_socket == -1)    {perror("accept error");return -1;    }    char recv_msg[1024];    char reply_msg[1024];        while(1)    {bzero(recv_msg, 1024);bzero(reply_msg, 1024);printf("reply:");scanf("%s", reply_msg);send(client_socket, reply_msg, 1024, 0);long byte_num = recv(client_socket, recv_msg, 1024, 0);recv_msg[byte_num] = '\0';printf("client said:%s\n", recv_msg);    }    return 0;}

客户端代码：

#include <stdio.h>#include <netinet/in.h>#include <sys/socket.h>#include <arpa/inet.h>#include <string.h>int main (int argc, const char * argv[]){    struct sockaddr_in server_addr;    server_addr.sin_family = AF_INET;    server_addr.sin_port = htons(11332);    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");    bzero(&(server_addr.sin_zero),8);    int server_socket = socket(AF_INET, SOCK_STREAM, 0);    if (server_socket == -1) {        perror("socket error");        return 1;    }    char recv_msg[1024];    char reply_msg[1024];    if (connect(server_socket, (struct sockaddr *)&server_addr, sizeof(struct sockaddr_in))==0)     {        while (1) {            bzero(recv_msg, 1024);            bzero(reply_msg, 1024);            long byte_num = recv(server_socket,recv_msg,1024,0);            recv_msg[byte_num] = '\0';            printf("server said:%s\n",recv_msg);            printf("reply:");            scanf("%s",reply_msg);            if (send(server_socket, reply_msg, 1024, 0) == -1) {                perror("send error");            }        }    }    // insert code here...    printf("Hello, World!\n");    return 0;}

由于是阻塞的，只能一问一答的通信。