粘包，Telnet,SSH,Wireshark

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一，粘包

原因：tcp为流式套接字，数据与数据间没有边界，导致多次数据粘到一起。

解决：

1.规定一些数据间的间隔符，"\aa","\r\n";

2.可以指定要发送对象的数据长度。

3.自己将数据打包。

1.上传接收粘连

1.用户端

#include <head.h>int connect_server(const char *ip,const char *port)
{int fd = socket(AF_INET,SOCK_STREAM,0);if (fd < 0)handle_error_ret("socket fail");struct sockaddr_in seraddr;memset(&seraddr,0,sizeof(seraddr));seraddr.sin_family = AF_INET;seraddr.sin_addr.s_addr = inet_addr(ip);seraddr.sin_port = htons(atoi(port));//"50000"  if (connect(fd,(const struct sockaddr *)&seraddr,sizeof(seraddr)) < 0)handle_error_ret("connect_server fail");return fd;
}//./cli 127.0.0.1 50000 filename 
int main(int argc, const char *argv[])
{if (argc != 4){printf("usage: %s <ip> <port> <filename>\n",argv[0]);return -1;}int fd = connect_server(argv[1],argv[2]);if (fd < 0)return -1;int fd_s = open(argv[3],O_RDONLY);if (fd_s < 0)handle_error_ret("open fail");write(fd,argv[3],strlen(argv[3])+1);
//	write(fd,argv[3],strlen(argv[3]));char buf[100] = {0};int ret = 0;while (1){ret = read(fd_s,buf,sizeof(buf));if (ret == 0)break;write(fd,buf,ret);}close(fd_s);close(fd);return 0;
}

2.服务器

#include <head.h>int init_server(const char *ip,const char *port)
{int fd = socket(AF_INET,SOCK_STREAM,0);if (fd < 0)handle_error_ret("socket fail");struct sockaddr_in seraddr;memset(&seraddr,0,sizeof(seraddr));seraddr.sin_family = AF_INET;seraddr.sin_addr.s_addr = inet_addr(ip);seraddr.sin_port = htons(atoi(port));//"50000"  if (bind(fd,(const struct sockaddr*)&seraddr,sizeof(seraddr)) < 0)handle_error_ret("bind fail");if (listen(fd,5) < 0)handle_error_ret("listen fail");return fd;}//./ser 127.0.0.1 50000 
int main(int argc, const char *argv[])
{int ret = 0;if (argc != 3){printf("Usage: %s <ip> <port>\n",argv[0]);return -1;}int listenfd = init_server(argv[1],argv[2]);if (listenfd < 0)return -1;int connfd = 0;if ((connfd = accept(listenfd,NULL,NULL)) < 0)handle_error_ret("accept fail");//读文件名 char buf[100] = {0};ret = read(connfd,buf,sizeof(buf));printf("ret = %d buf = %s\n",ret, buf);int fd_d = open(buf,O_WRONLY|O_CREAT|O_TRUNC,0666);if (fd_d < 0)handle_error_ret("open fail");while (1){ret = read(connfd,buf,sizeof(buf));printf("ret = %d buf1 = %s \n",ret,buf);if (ret == 0)break;write(fd_d,buf,ret);}close(fd_d);close(connfd);return 0;
}

3.注意

服务器和客户端不能写在同级别文件夹中

2.解决粘连

1.客户端

#include <head.h>int connect_server(const char *ip,const char *port)
{int fd = socket(AF_INET,SOCK_STREAM,0);if (fd < 0)handle_error_ret("socket fail");struct sockaddr_in seraddr;memset(&seraddr,0,sizeof(seraddr));seraddr.sin_family = AF_INET;seraddr.sin_addr.s_addr = inet_addr(ip);seraddr.sin_port = htons(atoi(port));//"50000"  if (connect(fd,(const struct sockaddr *)&seraddr,sizeof(seraddr)) < 0)handle_error_ret("connect_server fail");return fd;
}//./cli 127.0.0.1 50000 filename 
int main(int argc, const char *argv[])
{if (argc != 4){printf("usage: %s <ip> <port> <filename>\n",argv[0]);return -1;}int fd = connect_server(argv[1],argv[2]);if (fd < 0)return -1;int fd_s = open(argv[3],O_RDONLY);if (fd_s < 0)handle_error_ret("open fail");//write(fd,argv[3],strlen(argv[3])+1);write(fd,argv[3],strlen(argv[3]));//方式1 //sleep(1);//方式2 write(fd,"\r\n",2);char buf[100] = {0};int ret = 0;while (1){ret = read(fd_s,buf,sizeof(buf));if (ret == 0)break;write(fd,buf,ret);}close(fd_s);close(fd);return 0;
}

2.服务器

#include <head.h>int init_server(const char *ip,const char *port)
{int fd = socket(AF_INET,SOCK_STREAM,0);if (fd < 0)handle_error_ret("socket fail");struct sockaddr_in seraddr;memset(&seraddr,0,sizeof(seraddr));seraddr.sin_family = AF_INET;seraddr.sin_addr.s_addr = inet_addr(ip);seraddr.sin_port = htons(atoi(port));//"50000"  if (bind(fd,(const struct sockaddr*)&seraddr,sizeof(seraddr)) < 0)handle_error_ret("bind fail");if (listen(fd,5) < 0)handle_error_ret("listen fail");return fd;}//./ser 127.0.0.1 50000 
int main(int argc, const char *argv[])
{int ret = 0;if (argc != 3){printf("Usage: %s <ip> <port>\n",argv[0]);return -1;}int listenfd = init_server(argv[1],argv[2]);if (listenfd < 0)return -1;int connfd = 0;if ((connfd = accept(listenfd,NULL,NULL)) < 0)handle_error_ret("accept fail");//读文件名 char buf[100] = {0};FILE *fp = fdopen(connfd,"r");if (fp == NULL)handle_error_ret("fdopen fail");fgets(buf,sizeof(buf),fp);  //buf => 1.txt\r\nbuf[strlen(buf)-2] = '\0';//	ret = read(connfd,buf,sizeof(buf));
//	printf("ret = %d buf = %s\n",ret, buf);printf("buf = %s\n",buf);int fd_d = open(buf,O_WRONLY|O_CREAT|O_TRUNC,0666);if (fd_d < 0)handle_error_ret("open fail");while (1){//ret = read(connfd,buf,sizeof(buf));ret = fread(buf,1,sizeof(buf),fp);printf("ret = %d buf1 = %s \n",ret,buf);if (ret == 0)break;write(fd_d,buf,ret);}close(fd_d);close(connfd);return 0;
}