sock编程
struct sockaddr
struct sockaddr_in --> struct in_addr
struct hostent
htonl() htons() ntohl() ntohs()
int inet_aton(const char* cp,struct in_addr * inp);
in_addr_t inet_addr(const char* cp);
const char* inet_ntop(int af,const void* src,char* dst,socklen_t size);
struct hostent * gethostbyname(const char* name);
client :socket——connect——recv/send——close (one fd)
server:socket——bind——listen——accept——recv/send——close
(listendfd) (peerfd)
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 buf,int flags);
ssize_t send( int sockfd,void* buf,size_t buf,int flags);
int setsockopt(int sockfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));
int level ,int opname,const void* optval,socklen_t optlen
靓仔不想抄代码了呜呜,好困
————————client :
socket
connect
while(1)
close
————————server :
socket
bind
listen
accept
send //send是阻塞式函数
close
//第一次send可以正常执行,此时因为连接已经断开了,服务器会收到一个RST报文
//第二次send时,服务器会收到一个SIGPIPE信号 ,该信号的默认处理方式是终结进程。
//总结:client的连接关闭,会导致服务器进程奔溃,是一个不能接受的情况,因为服务器要服务其他的客户端。
————————client :
socket
connect
recv
close
————————server :
socket
bind
listen
accept
send sleep() send //服务器往一个已经断开了的连接上继续发送数据,会造成什么影响?
close
//数据在发送时是字节流,不是一个个的数据包
//数据之间是没有边界的概念 =》 TCP粘包问题
————————client :
socket
connect
recv recv
close
————————server :
socket
bind
listen
accept
send send
close
//recv的返回值为0的情况
————————client :
socket
connect
recv recv
close
————————server :
socket
bind
listen
accept
send close
723__01:使用select实现一个基于UDP的一对一即时聊天程序。
001:
#include <func.h>
#define IP "192.168.235.128"
#define PORT1 8080
#define PORT2 8081
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main()
{
struct sockaddr* addr=addr_create(IP,PORT1);
struct sockaddr* addr1=addr_create(IP,PORT2);
int sockfd=socket(AF_INET,SOCK_DGRAM,0);
if(sockfd==-1){error(1,errno,"socket");}
//addr1暴露一下?
int err=bind(sockfd,addr1,sizeof(*addr));
if(err==-1){error(1,errno,"bind");}
int epfd=epoll_create1(0);
struct epoll_event epev;
epev.events=EPOLLIN;
epev.data.fd=sockfd;
epoll_ctl(epfd,EPOLL_CTL_ADD,sockfd,&epev);
epev.data.fd=STDIN_FILENO;//标准输入的文件描述符,通常为 0
epoll_ctl(epfd,EPOLL_CTL_ADD,STDIN_FILENO,&epev);
struct epoll_event epev_arr[2];
char buff[4096];
while(1){
int num=epoll_wait(epfd,epev_arr,2,-1);
for(int i=0;i<num;i++){
int fd=epev_arr[i].data.fd;
if(fd==STDIN_FILENO){
fgets(buff,4096,stdin);
//给addr发消息
sendto(sockfd,buff,strlen(buff)+1,0,addr,sizeof(struct sockaddr));
}
if(fd==sockfd){
recvfrom(sockfd,buff,4096,0,NULL,NULL);
printf("REC::%s\n",buff);
}
}
}
close(sockfd);
return 0;
}
002: TIMEWAI OR BUG
#include <func.h>
#define IP "192.168.235.128"
#define IP1 "42.194.149.92"
#define PORT1 8082
#define PORT2 13332
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main()
{
struct sockaddr* addr=addr_create(IP,PORT1);
struct sockaddr* addr1=addr_create(IP1,PORT2);
int sockfd=socket(AF_INET,SOCK_DGRAM,0);
if(sockfd==-1){error(1,errno,"socket");}
//addr暴露一下
/* int err=bind(sockfd,addr,sizeof(*addr)); */
/* if(err==-1){error(1,errno,"bind");} */
int epfd=epoll_create1(0);
struct epoll_event epev;
epev.events=EPOLLIN;
epev.data.fd=sockfd;
epoll_ctl(epfd,EPOLL_CTL_ADD,sockfd,&epev);
epev.data.fd=STDIN_FILENO;//标准输入的文件描述符,通常为 0
epoll_ctl(epfd,EPOLL_CTL_ADD,STDIN_FILENO,&epev);
struct epoll_event epev_arr[2];
char buff[4096];
while(1){
int num=epoll_wait(epfd,epev_arr,2,-1);
for(int i=0;i<num;i++){
int fd=epev_arr[i].data.fd;
if(fd==STDIN_FILENO){
fgets(buff,4096,stdin);
//给addr1发送消息
sendto(sockfd,buff,strlen(buff)+1,0,addr1,sizeof(struct sockaddr));
}
if(fd==sockfd){
recvfrom(sockfd,buff,4096,0,NULL,NULL);
printf("REC::%s\n",buff);
}
}
}
close(sockfd);
return 0;
}
721作业:
01:在一对一聊天的基础上,使用select实现一对多的回显服务。(回显服务即接收到客户端发送的数据后,再回复给客户端)
一对一的喵:
//client.c
#include <func.h>
#define IP1 "192.168.235.128"
#define IP2 "42.194.149.92"
#define PORT1 8080
#define PORT2 13332
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main()
{
int sofd=socket(AF_INET,SOCK_STREAM,0);
if(sofd==-1){error(1,errno,"socket");}
struct sockaddr* addr=addr_create(IP1,PORT1);
int err=connect(sofd,addr,sizeof(*addr));
if(err==-1){error(1,errno,"connect");}
printf("connect sucess\n");
fd_set set;
FD_ZERO(&set);
char buff[100]={0};
while(1){
FD_SET(STDIN_FILENO,&set);
FD_SET(sofd,&set);
select(sofd+1,&set,NULL,NULL,NULL);
if(FD_ISSET(STDIN_FILENO,&set)){
memset(buff,0,sizeof(buff));
err=read(STDIN_FILENO,buff,sizeof(buff));
if(strcmp(buff,"byby\n")==0){break;}
send(sofd,buff,err-1,0);
}
if(FD_ISSET(sofd,&set)){
memset(buff,0,sizeof(buff));
err=recv(sofd,buff,sizeof(buff),0);
if(err==0){printf("byebye\n");break;}
printf("ret: %d,recv:%s \n",err,buff);
}
}
close(sofd);
return 0;
}
//server.c
#include <func.h>
#define IP1 "192.168.235.128"
#define IP2 "42.194.149.92"
#define PORT1 8080
#define PORT2 13332
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main()
{
int sofd=socket(AF_INET,SOCK_STREAM,0);
if(sofd==-1){error(1,errno,"socket");}
struct sockaddr* addr=addr_create(IP1,PORT1);
int err=bind(sofd,addr,sizeof(*addr));
if(err==-1){error(1,errno,"bimd");}
printf("bind sucess\n");
/* struct sockaddr_in* addrin=(struct sockaddr_in*)addr; */
/* printf("%s,%d\n",inet_ntoa(addr->sin_addr), */
/* sizeof((struct sockaddr_in*)addr.sin.port)); */
err=listen(sofd,1);
if(err==-1){error(1,errno,"listen");}
struct sockaddr_in addr2;
socklen_t len=sizeof(addr2);
int peerfd=accept(sofd,(struct sockaddr*)&addr2,&len);
printf("client :%s:%d has connect\n",inet_ntoa(addr2.sin_addr),
ntohs(addr2.sin_port));
// sofd--->peerfd
fd_set set;
FD_ZERO(&set);
char buff[100]={0};
while(1){
FD_SET(STDIN_FILENO,&set);
FD_SET(peerfd,&set);
select(peerfd+1,&set,NULL,NULL,NULL);
if(FD_ISSET(STDIN_FILENO,&set)){
memset(buff,0,sizeof(buff));
err=read(STDIN_FILENO,buff,sizeof(buff));
if(strcmp(buff,"byby\n")==0){break;}
send(peerfd,buff,err-1,0);
}
if(FD_ISSET(peerfd,&set)){
memset(buff,0,sizeof(buff));
err=recv(peerfd,buff,sizeof(buff),0);
if(err==0){printf("byebye\n");break;}
printf("ret: %d,recv:%s \n",err,buff);
}
}
close(sofd);
return 0;
}
一对多的服务器喵:
#include <func.h>
#define IP1 "192.168.235.128"
#define IP2 "42.194.149.92"
#define PORT1 8080
#define PORT2 13332
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main()
{
int sofd=socket(AF_INET,SOCK_STREAM,0);
if(sofd==-1){error(1,errno,"socket");}
struct sockaddr* addr=addr_create(IP1,PORT1);
int err=bind(sofd,addr,sizeof(*addr));
if(err==-1){error(1,errno,"bimd");}
printf("bind sucess\n");
/* struct sockaddr_in* addrin=(struct sockaddr_in*)addr; */
/* printf("%s,%d\n",inet_ntoa(addr->sin_addr), */
/* sizeof((struct sockaddr_in*)addr.sin.port)); */
err=listen(sofd,1);
if(err==-1){error(1,errno,"listen");}
struct sockaddr_in addr2;
socklen_t len=sizeof(addr2);
int peerfd=accept(sofd,(struct sockaddr*)&addr2,&len);
printf("client :%s:%d has connect\n",inet_ntoa(addr2.sin_addr),
ntohs(addr2.sin_port));
// sofd--->peerfd
fd_set set;
FD_ZERO(&set);
char buff[100]={0};
while(1){
FD_SET(STDIN_FILENO,&set);
FD_SET(peerfd,&set);
select(peerfd+1,&set,NULL,NULL,NULL);
if(FD_ISSET(STDIN_FILENO,&set)){
memset(buff,0,sizeof(buff));
err=read(STDIN_FILENO,buff,sizeof(buff));
if(strcmp(buff,"byby\n")==0){break;}
send(peerfd,buff,err-1,0);
}
if(FD_ISSET(peerfd,&set)){
memset(buff,0,sizeof(buff));
err=recv(peerfd,buff,sizeof(buff),0);
if(err==0){printf("byebye\n");break;}
printf("ret: %d,recv:%s \n",err,buff);
}
}
close(sofd);
return 0;
}
02:使用select编写聊天室程序:客户端和服务端使用tcp通信;服务端可以处理新客户端的连接和转发消息;客户端可以连入服务端并发送消息。
//server.c
#include <func.h>
#define IP1 "192.168.235.128"
#define IP2 "42.194.149.92"
#define PORT1 8080
#define PORT2 13332
//聊天室服务端
typedef struct conn_s{
int netfd;
int isalive;
}conn_t;
struct sockaddr* addr_create(const char* ip,int port ){
struct sockaddr_in* addr=(struct sockaddr_in*)malloc(sizeof(struct sockaddr_in));
memset(addr,0,sizeof(*addr));
addr->sin_family=AF_INET;
addr->sin_port=htons(port);
addr->sin_addr.s_addr=inet_addr(ip);
return (struct sockaddr*)addr;
}
int main(int argc,char* argv[])
{
struct sockaddr* addr=addr_create(IP1,PORT1);
int sofd=socket(AF_INET,SOCK_STREAM,0);
if(sofd==-1){error(1,errno,"socket");}
bind(sofd,(struct sockaddr *)&addr,sizeof(addr));
listen(sofd,10);
//用于管理文件描述符集合,用于指示哪些文件描述符正在监听的 I/O 事件已经发生
fd_set set;//select 监听的集合
FD_ZERO(&set);
FD_SET(sofd,&set);
conn_t list[1024];
memset(list,0,sizeof(list));
int index;
while(1){
fd_set temp_set;//构建此次的监听合计
memcpy(&temp_set,&set,sizeof(set));//cp ser temp_set
select (10,&temp_set,NULL,NULL,NULL);
if(FD_ISSET(sofd,&temp_set)){
int netfd=accept(sofd,NULL,NULL);
list[index].isalive=1;
list[index].netfd=netfd;
FD_SET(netfd,&set);//增加监听
index++;
}
for(int i=0;i<index;i++){
conn_t con=list[i];
//isalive && isset==has new massege
if(con.isalive==1&&FD_ISSET(con.netfd,&temp_set)){
char buff[100]={0};
int res_recv=recv(con.netfd,buff,sizeof(buff),0);
if(res_recv==0){
//return 0 disconnect
list[i].isalive=0;
FD_CLR(con.netfd,&set);
close(list[i].netfd);
}else{
//recv msg-->send client
for(int j=0;j<index;j++){
if(list[j].isalive==0||j==i){
continue;
//跳过断开连接的客户端,跳过发信息过来的客户端
}
send(list[j].netfd,buff,sizeof(buff),0);
}
}
}
}
}
printf("学姐我饿了\n");
printf("我也是\n");
close(sofd);
free(addr);
return 0;
}