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socket.c
308 lines (247 loc) · 11.9 KB
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socket.c
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/************************************************************************************************
ASSIGNMENT #3 : Proxy Cache Server
NAME : ��ö��
DATE : 2000. 12. 1
COMPILER : UNIX gcc 2.8.1, LINUX gcc 2.9.0
FILE : socket.c, cache.c, md5.c, proxy.h
*************************************************************************************************/
/*
������ log���� ���� �����δ� �״��� �ξ����ϴ�.
�������� �ʴ� url�Է½� core������ �����Ǹ鼭 ������������ �ߴ� �������� �������� proxy
server���� ���Ƿ� �����ؼ� �����ִ� error.html���� ����
*/
#include "proxy.h"
static void sig_cld(int); /* fork�� �ڽ� ���μ��� ���� �����Լ�.*/
static void my_alarm(int); /* socket�� ���� ������ ���Ѵ��� ����.*/
const int nSockVal = 1;
int main()
{
pid_t pid;
int n_cli, cli, n;
char buf[BUFFSIZE];
char *hash_input;
struct sockaddr_in proxy_serv;
printf("Cheoree's Proxy server started.\n");
/******* socket() ************************************************************************/
if( (listen_sd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
{
perror("Cannot open stream socket");
exit(1);
}
setsockopt( listen_sd, SOL_SOCKET, SO_REUSEADDR, &nSockVal, sizeof(nSockVal) );
bzero( (char *)&proxy_serv, sizeof(proxy_serv) );
proxy_serv.sin_family = AF_INET;
proxy_serv.sin_addr.s_addr = htonl(INADDR_ANY);
proxy_serv.sin_port = htons(PORTNUM);
/******* bind() *************************************************************************/
if( bind(listen_sd, (struct sockaddr*) &proxy_serv, sizeof(proxy_serv)) < 0 )
{
perror("Cannot bind local address\n");
exit(1);
}
/******* listen() ************************************************************************/
listen( listen_sd, MAX_NUM_CLIENT );
/*---------- Starting loop -----------------------------------------------------------------*/
for(;;)
{
n_cli = sizeof(cli);
bzero(buf, sizeof(buf));
bzero( (char*) &cli, n_cli );
/****** accept() **********************************************************************/
do{
accept_sd = accept(listen_sd, (struct sockaddr*) &cli, &n_cli);
}while(accept_sd == -1 && errno == (EINTR || EAGAIN) );
if( signal(SIGCHLD, sig_cld) == SIG_ERR )
perror("signal error.");
if( (pid = fork()) < 0 )
perror("fork error");
/* Child Process Generated */
else if( pid == 0)
{
if( accept_sd == -1 )
exit(1);
close(listen_sd);
signal(SIGALRM, my_alarm);
do{ /*����������(Client) REQUEST�� �´�.*/
alarm(TIMEOUT);
n = read(accept_sd, buf, BUFFSIZE);
}while( n == -1 && errno == EINTR );
/*���� REQUEST�� hashing*/
hash_input = get_hash_url(buf);
/*hashed URL�� �Է°����� �۾�*/
/*�ڽ��� �����ϴ� ���� ���κ��� ó���ϴ� �Լ�. (cache.c ���Ͽ� �ֽ�.) */
cacheing( hash_input, buf );
exit(0);
}
/* Child exit */
close(accept_sd); /*�θ� ���μ����� socket descriptor�� �ݾ���.*/
}
/*-------- End of loop -------------------------------------------------------------------*/
}
/***********************************************************************************************
MISS �϶� �����Ǵ� �Լ��μ� ������ response(header, data)�� �о��ͼ� ������������ �����ϰ� �ٽ� cache
�� �����ϴ� ���� �Ѵ�.
************************************************************************************************/
void connect_web_srv( char *buf, char *whole_dir )
{
int qfile, write_n, read_n, a, b;
char domain_name[DNSIZE], response[BUFFSIZE];
char ws_request[BUFFSIZE];
struct hostent *hp; /*�������� �ּҸ� ���������� �ޱ����� �ּ� ����ü.*/
struct sockaddr_in web_serv;
bzero(response, sizeof(response));
bzero(domain_name, sizeof(domain_name));
bzero(ws_request, sizeof(ws_request));
/****** socket() **************************************************************************/
if( (connect_sd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
{
perror("Cannot open stream socket.");
exit(1);
}
/*domain name���� parsing*/
for(a=0;a<DNSIZE;a++)
{
if( buf[a] == '/' )
{
for(b=0;b<DNSIZE-a;b++)
{
if( buf[a+b+2] == '/' )
break;
domain_name[b] = buf[a+b+2];
}
break;
}
}
/* �������� �ּҿ� ���� ������ �´�.*/
if( (hp = gethostbyname(domain_name)) == NULL )
{
errpage(domain_name); /*�߰� ���� �Լ�*/
access_local_cache("./error.html"); /* " */
exit(1);
}
bzero( (char*) &web_serv, sizeof(web_serv) );
web_serv.sin_addr = *( (struct in_addr*)hp->h_addr_list[0] );
web_serv.sin_family = AF_INET;
web_serv.sin_port = htons(WEBPORT);
/****** connect() ************************************************************************/
if( connect(connect_sd, (struct sockaddr*)&web_serv, sizeof(web_serv)) < 0)
{
perror("Connect error.");
exit(1);
}
/* �������� Moved���� ������ ������ �� response�� �ƿ� �� ���� �DZ���� request header
�� �ٽ� �Ľ��ϴ� �Լ��̴�.*/
get_ws_request(buf, ws_request);
/* cache�� �������κ��� �ƿ� ����Ÿ�� ������ ������ ���� open() */
qfile = open( whole_dir, O_WRONLY | O_CREAT, 0666 );
write(connect_sd, ws_request, BUFFSIZE ); /* �������� request header ����.*/
do{
alarm(TIMEOUT);
while( (read_n = read(connect_sd, response, MAXLINE )) > 0 )
{
do{
write_n = write(accept_sd, response, read_n);/*Ŭ���̾�Ʈ�� ����Ÿ ����.*/
write( qfile, response, read_n ); /*cache�� ����Ÿ ����. */
bzero(response, sizeof(response));
}while( write_n == -1 && errno == EINTR);
}
}while( read_n == -1 && errno == EINTR );
close(qfile);
close(accept_sd); /* ���� ����ũ����, ���ϵ���ũ���� ���� �ݴ´�. ���� ����.*/
close(connect_sd);
printf("MISS : [ip:%s] ", inet_ntoa(web_serv.sin_addr));
printf("%s\n", strtok(buf, "\n"));
}
/*******************************************************************************************
HIT �϶� �����Ǵ� �Լ��μ� ���������� connect���� ������ ���ŵȴ�. local server�� cache�� Access
*******************************************************************************************/
void access_local_cache( char *whole_dir )
{
int qfile, read_n;
char filebuf[BUFFSIZE];
qfile = open( whole_dir, O_RDONLY );
while( (read_n = read(qfile, filebuf, MAXLINE )) > 0 )
{
write(accept_sd, filebuf, read_n);
bzero(filebuf, sizeof(filebuf));
}
printf("HIT : %s\n", whole_dir);
close(qfile);
}
/**************************************************************************
REQUEST header���� http://xxx.xxx.xxx/xxx/xxx/xxx.xx �κи��� �߶� �Լ�.
***************************************************************************/
char * get_hash_url( char *buf )
{
char temp[BUFFSIZE];
char *hash_input;
bzero(temp, sizeof(temp) );
strncpy(temp, buf, BUFFSIZE);
hash_input = strtok(temp, " ");
hash_input = strtok(NULL, " ");
return hash_input;
}
/**************************************************
domain name�� ���ŵ� REQUEST header�� ����� �Լ�.
***************************************************/
void get_ws_request( char *buf, char *ws_request)
{
int i,j;
int a=0, b=0;
/* ' '�� ���������� �����س�����. ' '�κ��� �迭��ġ�� ����. */
for(i=0;i<BUFFSIZE;i++)
{
ws_request[i] = buf[i];
if( buf[i] == ' ' ) break;
}
/* '/'���ڰ� 3�� ���ö����� �迭�� �پ��Ѵ´�. 3���������� ��ġ����.*/
while( b < 3 )
if( buf[a++] == '/' )
b++;
/* ' '���ں��� '/'���ڰ� 3�� ���°������� �پ��Ѱ� �ٽ� �迭 ����.*/
for(j=0;j<BUFFSIZE-i;j++)
{
ws_request[j+i+1] = buf[a+j-1];
if( buf[j] == '\0')
break;
}
}
static void my_alarm( int signo )
{
if( signal(SIGALRM, my_alarm) == SIG_ERR)
perror("signal error");
close(accept_sd);
close(connect_sd);
printf("Alarm fucntion called.\n");
exit(0);
}
static void sig_cld( int signo )
{
pid_t pid;
int status;
//printf("child terminated.\n");
if( signal(SIGCHLD, sig_cld) == SIG_ERR )
perror("signal error");
if( (pid = wait(&status)) < 0)
perror("wait error");
return;
}
/*************************************************************************
�߰� ���� �Լ��μ� hostent �ּ� ����ü�� ���ϵ� �����Ͱ��� ���� ���� ��, ����
���� �ʴ� url�� �Է����� ���������� (proxy server����) ���Ƿ� ��������������
������ ���������� ������.
**************************************************************************/
void errpage(char *url)
{
char msg[300];
int er;
bzero(msg, sizeof(msg));
printf("domain: %s\n", url);
sprintf(msg, "<html><title>Connect Error - Cheoree Proxy Server</title>
<body bgcolor = silver><br><font size = 2><b>Error</b> - http://%s/ <b>is Invalid URL</b>
</font></body></html>", url);
er = open("error.html", O_WRONLY | O_CREAT, 0644 );
write(er, msg, 300);
close(er);
}
/************************* End of File ****************************************************/