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科林Linux6_网络

news 来源：原创 2024/9/28 17:51:53

#include<sys/socket.h>
#include<arpa/inet.h>    //大小端转换
#include<netdb.h>    //DNS

一、Socket套接字

为了开发网络应用，系统提供一套API函数接口，用于网络应用开发，这些接口称为套接字函数

struct sockaddr_int{sin_family=AF_INET;sin_port=8080;sin_addr.s_addr=127.0.0.1;
}addr;

int sockfd=socket(AF_INET,SOCK_STREAM|SOCK_DRAM,0);    //socket创建
//成功返回sockfd，失败返回-1bind(int sockfd,struct sockaddr* addr/*使用旧的网络信息结构体，向前兼容*/,socklen_t addrlen);
//成功返回0，失败返回-1。对socket设置自定义信息，保持信息不变listen(sockfd,backlog/*等待连接队列大小,默认128*/);//监听连接过程以及对应的链接事件（TCPServer）
//成功返回0，失败返回-1

htons();    //本机到网络16位，小端转大端端口号
htonl();    //小端转大端p
ntohs();
ntohl();
inet_ntop();    //大端序转字符串
inet_pton();
inet_addr();

connect(int sockfd,struct sockaddr* destaddr,sockelen_t addrlen);    //请求连接函数（发起握手请求）
//成功返回0，失败返回-1，如果网络异常可能引发阻塞int clientsock = accept(int serversocket,struct sockaddr* clientaddr,socklen_t* addrlen);    //阻塞等待并建立连接函数（完成三次握手），连接成功后立即返回
//成功返回sock，失败返回-1,如果网络异常可能引发阻塞send(int sockfd,char* msg,int len,MSG_NOSIGNAL/*写忽略信号*/);    //向目标发送网络信息recv(int sockfd,char* buffer,int size,MSG_DONTWAIT/*非阻塞读*/);    //读取接收网络信息

TCP连接方式：keep-alive长链接，close短链接

//TcpServer.h
#include<mysock.h>#define SHUTDOWN 1/*支持 tcp连接 及连接反馈的模型*/int main(){//close 循环持续连接int server_sock,client_sock;struct sockaddr_in addrClient;socklen_t addrlen;server_sock=net_initializer();printf("Test tcp server version 1.0\n");char client_ip[16];while(SHUTDOWN){addrlen=sizeof(addrClient);client_sock=ACCEPT(server_sock,(struct sockaddr*)&addrClient,&addrlen);bzero(client_ip,16);inet_ntop(AF_INET,&addrClient.sin_addr.s_addr,client_ip,16);//大端序转字符串printf("client port %d,client ip %s\n",ntohs(addrClient.sin_port),client_ip);first_response(client_sock,client_ip);business(client_sock);//读取请求，处理请求，反馈响应close(client_sock);}close(server_sock);printf("server tis done\n");return 0;
}

//TcpClient.h
#include<mysock.h>int main(){//创建套接字int server_sock=SOCKET(AF_INET,SOCK_STREAM,IPPROTO_TCP);//服务器套接字信息struct sockaddr_in addrServer;bzero(&addrServer,sizeof(addrServer));addrServer.sin_family=AF_INET;addrServer.sin_port=htons(8080);addrServer.sin_addr.s_addr=inet_addr("82.157.31.74");CONNECT(server_sock,(struct sockaddr*)&addrServer,sizeof(addrServer));int nRecvNum=0;int nSendNum=0;char recvBuf[1024]="";char sendBuf[1024]="";nRecvNum=RECV(server_sock,recvBuf,sizeof(recvBuf),0);printf("server:%s\n",recvBuf);fgets(sendBuf,sizeof(sendBuf),stdin);nSendNum=SEND(server_sock,sendBuf,sizeof(sendBuf),0);nRecvNum=RECV(server_sock,recvBuf,sizeof(recvBuf),0);printf("server:%s\n",recvBuf);close(server_sock);return 0;
}

套接字函数的包裹，网络功能的包裹：在系统函数的基础上，拓展函数的功能，在函数的基础上包裹一层功能更丰富的函数

//myscok.h
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<errno.h>
#include<ctype.h>
#include<time.h>int SOCKET(int domain,int type,int protocol);
int BIND(int sockfd,const struct sockaddr* addr,socklen_t addrlen);
int LISTEN(int sockfd,int backlog);
int CONNECT(int sockfd,const struct sockaddr* addr,socklen_t addrlen);
int ACCEPT(int sockfd,struct sockaddr* addr,socklen_t* addrlen);
ssize_t RECV(int sockfd,void* buf,size_t len,int flags);
ssize_t SEND(int sockfd,const void* buf,size_t len,int flags);int net_initializer();
void first_response(int sock,char* cip);//业务处理模块
void business(int client_sock);

//mysock.c
#include<mysock.h>int SOCKET(int domain,int type,int protocol){int sock;if((sock=socket(domain,type,protocol))==-1){perror("socket create failed");return -1;}return sock;
}int BIND(int sockfd,const struct sockaddr* addr,socklen_t addrlen){if((bind(sockfd,addr,addrlen))==-1){perror("bind call failed");return -1;}return 0;
}int LISTEN(int sockfd,int backlog){if((listen(sockfd,backlog))==-1){perror("listen call failed");return -1;}return 0;
}int CONNECT(int sockfd,const struct sockaddr* addr,socklen_t addrlen){if((connect(sockfd,addr,addrlen))==-1){perror("connect call failed");return -1;}return 0;
}int ACCEPT(int sockfd,struct sockaddr* addr,socklen_t* addrlen){int sock;if((sock=accept(sockfd,addr,addrlen))==-1){perror("accept call failed");return -1;}return sock;
}ssize_t RECV(int sockfd,void* buf,size_t len,int flags){ssize_t size;if((size=recv(sockfd,buf,len,flags))==-1){if(errno==EAGAIN){printf("recv nonblock return\n");}else{perror("recv call failed");}return -1;}return size;
}ssize_t SEND(int sockfd,const void* buf,size_t len,int flags){ssize_t size;if((size=send(sockfd,buf,len,flags))==-1){perror("send call failed");return -1;}return size;
}int net_initializer(){//套接字信息struct sockaddr_in addrServer;bzero(&addrServer,sizeof(addrServer));addrServer.sin_family=AF_INET;addrServer.sin_port=htons(8080);addrServer.sin_addr.s_addr=htonl(INADDR_ANY);//创建套接字int server_sock;server_sock=SOCKET(AF_INET,SOCK_STREAM,0);BIND(server_sock,(struct sockaddr*)&addrServer,sizeof(addrServer));LISTEN(server_sock,128);return server_sock;
}void first_response(int sock,char* cip){char response[1024];bzero(response,sizeof(response));sprintf(response,"hi, %s wellcome test TCP server.\n",cip);SEND(sock,response,strlen(response),0);
}void business(int client_sock){//读取一次客户端请求，处理后，立刻断开ssize_t recv_size;char recv_buffer[1024];bzero(recv_buffer,sizeof(recv_buffer));recv_size=RECV(client_sock,recv_buffer,sizeof(recv_buffer),0);if((strcmp(recv_buffer,"time\n")==0) || (strcmp(recv_buffer,"time")==0)){//响应系统时间time_t tp;char tbuf[1024];bzero(tbuf,sizeof(tbuf));ctime_r(&tp,tbuf);SEND(client_sock,tbuf,strlen(tbuf),0);printf("server,response time success.\n");close(client_sock);}else{//数据处理，大小写转换 toupper()int cnt=0;while(cnt<recv_size){recv_buffer[cnt]=toupper(recv_buffer[cnt]);cnt++;}SEND(client_sock,recv_buffer,recv_size,0);printf("server,response data sucess.\n");close(client_sock);}
}