????????TCP?????????????socket?????????????????????
????????????????????￡?
??????1????????????socket??
??????2????????????????????????????bind??
??????3???????????????????????????????????listen??
??????4??????????????????????????????????????????????μ??????????????????accept??
??????5???÷?????????????????????send/recv??
??????6??????????????????????
??????7???????????
?????????????????￡?
??????1????????????socket??
??????2?????????????????????connect??
??????3??????????????????send/recv??
??????4??????????
????????????????????????????????????????????????????suse linux??
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <memory.h>
#include <unistd.h>
//#include <linux/in.h>
#include <netinet/in.h>
//#include <linux/inet_diag.h>
#include <arpa/inet.h>
#include <signal.h>
/**
???? sockaddr  sockaddr_in  socketaddr_un???
http://maomaozaoyue.blog.sohu.com/197538359.html
*/
#define PORT    11910   //?????????
#define BACKLOG 5       //???????????г???
#define buflen  1024
void process_conn_server(int s);
void sig_pipe(int signo);
int ss??sc;  //ss???????socket????????sc???????????socket??????
int main(int argc??char *argv[])
{
struct sockaddr_in server_addr; //?洢????????socket?????
struct sockaddr_in client_addr; //?洢????? socket?????
int err;    //?????
pid_t pid;  //?????е?ID
/*****************socket()***************/
ss = socket(AF_INET??SOCK_STREAM??0); //??????????л????????????????????????
if(ss<0)
{
printf("server : server socket create error ");
return -1;
}
//??????
sighandler_t ret;
ret = signal(SIGTSTP??sig_pipe);
if(SIG_ERR == ret)
{
printf("???????? ");
return -1;
}
else
printf("??????? ");
/******************bind()****************/
//??????????
memset(&server_addr??0??sizeof(server_addr));
server_addr.sin_family = AF_INET;           //Э????
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);   //??????
server_addr.sin_port = htons(PORT);
err = bind(ss??(struct sockaddr *)&server_addr??sizeof(sockaddr));
if(err<0)
{
printf("server : bind error ");
return -1;
}
/*****************listen()***************/
err = listen(ss??BACKLOG);   //???ü???????д?С
if(err < 0)
{
printf("server : listen error ");
return -1;
}
/****************accept()***************/
/**
?????????????????????????????????????????
????1?????????????μ?????????;2????????????C/S??????
????????????????????????????д???????????????
??????????????й?? ??????????????? ????????й??
?????????????????????????????е?????????????????
?????????????????fork??????????????????????????
????????????????????????????????????????
*/
for(;;)
{
socklen_t addrlen = sizeof(client_addr);
//accept???????????????????
sc = accept(ss??(struct sockaddr *)&client_addr??&addrlen);  //??????????????????? ?????????
if(sc < 0)  //????
{
continue;   //??????????
}
else
{
printf("server : connected ");
}
//??????????????????????????
pid = fork();
//fork ????????????????? 0 ???????????????? ID
if(pid == 0)        //???????????????
{
close(ss);
process_conn_server(sc);
}
else
{
close(sc);
}
}
}
/**
?????????????????????????????????????????????
????????????????????????????????
*/
//???????? s ????????????
void process_conn_server(int s)
{
ssize_t size = 0;
char buffer[buflen];  //?????????????
for(;;)
{
//?????
for(size = 0;size == 0 ;size = read(s??buffer??buflen));
//???????????????????
printf("%s"??buffer);
//????????
if(strcmp(buffer??"quit") == 0)
{
close(s);   //???????0????????-1
return ;
}
sprintf(buffer??"%d bytes altogether "??size);
write(s??buffer??strlen(buffer)+1);
}
}
void sig_pipe(int signo)
{
printf("catch a signal ");
if(signo == SIGTSTP)
{
printf("????? SIGTSTP ??? ");
int ret1 = close(ss);
int ret2 = close(sc);
int ret = ret1>ret2?ret1:ret2;
if(ret == 0)
printf("??? : ???????? ");
else if(ret ==-1 )
printf("??? : δ???????? ");
exit(1);
}
}