C语言Socket编程（TCP与UDP）

C语言Socket编程（TCP与UDP）

UDP：

//udp_server.c:
#include 
#include 
#include 
#include 
#include 
#include 
#define PORT_SERV 8889
#define BUFF_LEN 1024static 
void UDP_server_process(int s,struct sockaddr_in *client)
{    
	int n,len,PORT_INT,count = 0;    
	char buff[BUFF_LEN] = {0};    
	char *IP_STR;    
	len = sizeof(*client);    
	while(1){        
		n = recvfrom(s,buff,BUFF_LEN,0,(struct sockaddr *)client,&len);        
		IP_STR = (char *)inet_ntoa(client->sin_addr);        
		PORT_INT = ntohs(client->sin_port);        
		printf("%d Received Address:%s:%d\n",count,IP_STR,PORT_INT);        
		printf("%d Received Message:%s\n",count++,buff);        
		printf("\n");        
		sendto(s,buff,n,0,(struct sockaddr *)client,len);        
		memset(buff,0,BUFF_LEN);            
	}
}
int main(int argc,char **argv)
{    
	int s;    
	struct sockaddr_in addr_serv,addr_clie;    
	s = socket(AF_INET,SOCK_DGRAM,0);    
	memset(&addr_serv,0,sizeof(addr_serv));    
	addr_serv.sin_family = AF_INET;    
	addr_serv.sin_addr.s_addr = htonl(INADDR_ANY);    
	addr_serv.sin_port = htons(PORT_SERV);    
	bind(s,(struct sockaddr *)&addr_serv,sizeof(addr_serv));
	UDP_server_process(s,&addr_clie);    
	return 0;
}

//udp_client.c:
#include 
#include 
#include 
#include 
#include 
#include 


#define PORT_SERV 8889


#define BUFF_LEN 1024
#define SERV_IP "192.168.31.34"
static void UDP_client_process(int s,struct sockaddr_in *client)
{
    char RecBuff[BUFF_LEN]="\n";
    char SendBuff[BUFF_LEN] = {0};
    int n;
    struct sockaddr_in from;
    int len = sizeof(*client);
    printf("please input message!\n");
    while(1){
        n = read(0,SendBuff,BUFF_LEN);
        SendBuff[n++] = '\0';
        sendto(s,SendBuff,n,0,(struct sockaddr *)client,len);
    //    recvfrom(s,RecBuff,BUFF_LEN,0,(struct sockaddr*)&from,&len);
    //    printf("recved:%s\n",RecBuff);
    }
}


int main(int argc,char **argv)
{
    int s;
    struct sockaddr_in addr_serv,addr_clie;
    char *msg;
    /*
    if(argc != 3){
        printf("parameter is error!\n");
        printf("format:ip port\n");
        return -1;
    }
    */
    s = socket(AF_INET,SOCK_DGRAM,0);
    memset(&addr_clie,0,sizeof(addr_clie));
    addr_clie.sin_family = AF_INET;
   
    /*inet_addr(SERV_IP); inet_addr(argv[1])*/   
    addr_clie.sin_addr.s_addr = htonl(INADDR_ANY);
   
    /*htons(atoi(argv[2]));*/
    addr_clie.sin_port = htons(PORT_SERV);


    UDP_client_process(s,&addr_clie);


    close(s);
    return 0;
}

TCP

//tcp_server.c:

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define SERVER_PORT 6666


/*监听后，一直处于accept阻塞状态，直到有客户端连接，当客户端如数quit后，断开与客户端的连接*/
int main()
{
    int sock;
    //声明两个套接字sockaddr_in结构体变量，分别表示客户端和服务器
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    int addr_len = sizeof(server_addr);
    int client;
    char buffer[1024];
    int DataNum;
    //socket函数，失败返回-1
    //int socket(int domain, int type, int protocol);
    //第一个参数表示使用的地址类型，一般都是ipv4，AF_INET
    //第二个参数表示套接字类型：tcp：面向连接的稳定数据传输SOCK_STREAM
    //第三个参数设置为0
    if((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        perror("socket");
        return 1;
    }
    bzero(&server_addr, sizeof(server_addr));
    //初始化服务器端的套接字，并用htons和htonl将端口和地址转成网络字节序
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    //ip可以是本服务器的ip，也可以用宏INADDR_ANY代替，代表0.0.0.0，表明所有地址
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    //对于bind，accept之类的函数，里面套接字参数都是需要强制转换成(struct sockaddr *)
    //bind三个参数：服务器端的套接字的文件描述符，
    if(bind(sock, (struct sockaddr *)&server_addr, addr_len) < 0)
    {
        perror("connect");
        return 1;
    }
    //设置服务器上的socket为监听状态
    if(listen(sock, 5) < 0)
    {
        perror("listen");
        return 1;
    }
    while(1)
    {
        printf("监听端口: %d\n", SERVER_PORT);
        //调用accept函数后，会进入阻塞状态
        //accept返回一个套接字的文件描述符，这样服务器端便有两个套接字的文件描述符，
        //sock和client。
        //sock仍然继续在监听状态，client则负责接收和发送数据
        //client_addr是一个传出参数，accept返回时，传出客户端的地址和端口号
        //addr_len是一个传入-传出参数，传入的是调用者提供的缓冲区的client_addr的长度，以避免缓冲区溢出。
        //传出的是客户端地址结构体的实际长度。
        //出错返回-1
        client = accept(sock, (struct sockaddr*)&client_addr, (socklen_t*)&addr_len);
        if(client < 0)
        {
            perror("accept");
            continue;
        }
        printf("等待消息...\n");
        //inet_ntoa ip地址转换函数，将网络字节序IP转换为点分十进制IP
        //表达式：char *inet_ntoa (struct in_addr);
        printf("IP is %s\n", inet_ntoa(client_addr.sin_addr));
        printf("Port is %d\n", htons(client_addr.sin_port));
        int n = 0;
        while(1)
        {
            DataNum = recv(client, buffer, 1024, 0);
            if(DataNum < 0)
            {
                perror("recv null");
                continue;
            }
            if(strcmp(buffer, "quit") == 0)
                break;
            printf("读取消息:%s\n",buffer);
            memset(buffer,0,sizeof(buffer));
        
            printf("发送消息:");
            fflush( stdout );
            n = read(0,buffer,1024);
            send(client, buffer, n, 0);
            printf("\n");
            if(strcmp(buffer, "quit") == 0)
                break;
        }
    }
    close(sock);
    return 0;
}

//tcp_client.c:

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define SERVER_PORT 6666
/*连接到服务器后，会不停循环，等待输入，输入quit后，断开与服务器的连接*/
int main()
{
    //客户端只需要一个套接字文件描述符，用于和服务器通信
    int sock;
    //描述服务器的socket
    struct sockaddr_in server_addr;
    char buffer[1024];
    int DataNum;
    if((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        perror("socket");
        return 1;
    }
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    //指定服务器端的ip，本地测试：127.0.0.1
    //inet_addr()函数，将点分十进制IP转换成网络字节序IP
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    if(connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
    {
        perror("connect");
        return 1;
    }
    int n = 0;
    while(1)
    {
        printf("发送消息:");
        fflush( stdout );
        n = read(0,buffer,1024);
        buffer[n++] = '\0';
        printf("\n");
        send(sock, buffer, n, 0);
        if(strcmp(buffer, "quit") == 0)
            break;
        memset(buffer,0,sizeof(buffer));
        DataNum = recv(sock, buffer, 1024, 0);
        printf("接收消息：%s\n", buffer);
        memset(buffer,0,sizeof(buffer));
    }
    close(sock);
    return 0;
}