UNIX-Linux socket网络编程（下）：UDP和TCP通信的简单范例

一、UDP通信

本地通信：

a.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

typedef struct sockaddr* SP;

int main()
{
	// 创建socket
	int sockfd = socket(AF_LOCAL,SOCK_DGRAM,0);
	if(0 > sockfd)
	{
		perror("socket");
		return -1;
	}

	// 准备地址
	struct sockaddr_un addr,src_addr;
	addr.sun_family = AF_LOCAL;
	strcpy(addr.sun_path,"socketA");

	// 绑定会自动创建socket文件
	remove(addr.sun_path);
	if(bind(sockfd,(SP)&addr,sizeof(addr)))
	{
		perror("bind");
		return -1;
	}

	for(;;)
	{
		char buf[256] = {};
		socklen_t len;

		// 接收
		recvfrom(sockfd,buf,sizeof(buf),0,(SP)&src_addr,&len);
		printf("recv:%s from:%s\n",buf,src_addr.sun_path);
		if(!strcmp("quit",buf))
		{
			printf("通信结束!\n");
			break;
		}

		// 发送
		strcat(buf,"!");
		sendto(sockfd,buf,strlen(buf)+1,0,(SP)&src_addr,len);
	}
	// 关闭
	close(sockfd);
	// 删除
	remove(addr.sun_path);
}

b.c。

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

typedef struct sockaddr* SP;

int main()
{
	// 创建socket对象
	int sockfd = socket(AF_LOCAL,SOCK_DGRAM,0);
	if(0 > sockfd)
	{
		perror("socket");
		return -1;
	}

	// 准备绑定地址
	struct sockaddr_un addr,dest_addr;
	addr.sun_family = AF_LOCAL;
	strcpy(addr.sun_path,"socketB");
	dest_addr.sun_family = AF_LOCAL;
	strcpy(dest_addr.sun_path,"socketA");

	// 绑定
	remove(addr.sun_path);
	if(bind(sockfd,(SP)&addr,sizeof(addr)))
	{
		perror("bind");
		return -1;
	}

	for(;;)
	{
		char buf[256] = {};
		printf(">");
		gets(buf);

		// 发送
		sendto(sockfd,buf,strlen(buf)+1,0,(SP)&dest_addr,sizeof(dest_addr));
		if(!strcmp("quit",buf))
		{
			printf("通信结束!\n");
			break;
		}
		socklen_t len;
		// 接收
		recvfrom(sockfd,buf,sizeof(buf),0,(SP)&addr,&len);
		printf("recv:%s\n",buf);
		
	}

	// 关闭
	close(sockfd);

	// 删除
	remove(addr.sun_path);
}

网络通信：

server.c。

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

typedef struct sockaddr* SP;
int main()
{
    int sockfd = socket(AF_INET,SOCK_DGRAM,0);
    if(0 > sockfd)
    {
        perror("socket");
        return -1;
    }

    struct sockaddr_in addr,src_addr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(端口号);
    addr.sin_addr.s_addr = inet_addr("ip");

    if(bind(sockfd,(SP)&addr,sizeof(addr)))
    {
        perror("bind");
        return -1;
    }

    for(;;)
    {
        char buf[256] = {};
        socklen_t len;
        recvfrom(sockfd,buf,sizeof(buf),0,(SP)&src_addr,&len);
        printf("recv:%s\n",buf);
        if(!strcmp("quit",buf))
        {
        	printf("通信结束!\n");
        	break;
        }

        sendto(sockfd,"hehe",5,0,(SP)&src_addr,len);
    }

    close(sockfd);
}

client.c

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

typedef struct sockaddr* SP;

int main()
{
	int sockfd = socket(AF_INET,SOCK_DGRAM,0);
	if(0 > sockfd)
	{
		perror("socket");
		return -1;
	}

	// 目标地址
	struct sockaddr_in addr;
	addr.sin_family = AF_INET;
	addr.sin_port = htons(端口号);
	addr.sin_addr.s_addr = inet_addr("目标ip");

	for(;;)
	{
		char buf[256] = {};
		printf(">");
		gets(buf);

		sendto(sockfd,buf,strlen(buf)+1,0,(SP)&addr,sizeof(addr));
		if(!strcmp("quit",buf))
		{
			printf("通信结束!\n");
			break;
		}

		socklen_t len;
		recvfrom(sockfd,buf,sizeof(buf),0,(SP)&addr,&len);
		printf("%s\n",buf);
	}

	close(sockfd);
}

二、TCP通信

server.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

typedef struct sockaddr* SP;

void* run(void* arg)
{
    // 备份客户端描述符
    int clifd = *(int*)arg;

    for(;;)
    {
        char buf[256] = {};
        int ret = read(clifd,buf,sizeof(buf));
        if(0 > ret)
        {
            printf("客户端异常结束!\n");
            break;
        }

        printf("recv:%s\n",buf);
        if(!strcmp("quit",buf))
        {
            printf("通信结束!\n");
            break;
        }

        write(clifd,"xixi",5);
    }

    close(clifd);
}
int main()
{
    // 创建socket
    int sockfd = socket(AF_INET,SOCK_STREAM,0);
    if(0 > sockfd)
    {
        perror("sockfd");
        return -1;
    }

    // 准备地址
    struct sockaddr_in addr,cliaddr;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(端口号);
    addr.sin_addr.s_addr = inet_addr("ip");
    // 绑定
    if(bind(sockfd,(SP)&addr,sizeof(addr)))
    {
        perror("bind");
        return -1;
    }

    // 监听
    listen(sockfd,10);

    // 等待连接
    for(;;)
    {
        socklen_t len;
        // 等待客户端连接并获取描述符
        int clifd = accept(sockfd,(SP)&cliaddr,&len);

        // 创建线程为客户端服务
        pthread_t tid;
        pthread_create(&tid,NULL,run,&clifd);
        usleep(500);
    }
}

client.c

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

typedef struct sockaddr* SP;

int main()
{
	int sockfd = socket(AF_INET,SOCK_STREAM,0);
	if(0 > sockfd)
	{
		perror("socket");
		return -1;
	}

	struct sockaddr_in addr;
	addr.sin_family = AF_INET;
	addr.sin_port = htons(端口号);
	addr.sin_addr.s_addr = inet_addr("目标ip");

	if(connect(sockfd,(SP)&addr,sizeof(addr)))
	{
		perror("connect");
		return -1;
	}

	for(;;)
	{
		char buf[256] = {};
		printf(">");
		gets(buf);
		write(sockfd,buf,strlen(buf)+1);
		if(!strcmp("quit",buf))
		{
			printf("通信结束!\n");
			break;
		}
		read(sockfd,buf,sizeof(buf));
		printf("server:%s\n",buf);
	}

	close(sockfd);
}