/**
* relayd.c -- a relay daemon (using one targethost/port)
* --
* $Id: relayd.c,v 1.4 1998/02/06 16:30:21 marcus Exp $
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* "The Java Telnet Applet" is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* relayd.c (c) 1996,1997 Marcus Meissner <marcus@mud.de> */
/* Compile with: cc -o relayd relayd.c
* or: gcc -o relayd relayd.c
* Solaris: (g)cc -o relayd relayd.c -lsocket -lnsl
*/
/* this program expects the string:
* "relay <hostname> <port>" or "relay <hostname>"
* after connecting. It will then try to connect to the specified host
* if failures occur, it will terminate the connection.
*/
/* adjust this to a reasonable limit */
#define MAXUSERS 120
/* message printed if all slots are used ... */
#define FAILMESSAGE "Sorry, all slots are full.\r\n"
/* string printed before connection */
#define RELAYHEADER "Relayd (c) Marcus Meissner\r\n"
#include <stdio.h>
#ifdef _WIN32
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <winsock.h>
#include <io.h>
#define ioctl ioctlsocket
#define write(h,buf,size) send(h,buf,size,0)
#define read(a,b,c) recv(a,b,c,0)
#define close _lclose
#define EINPROGRESS WSAEWOULDBLOCK
#else
#include <unistd.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/signal.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif
#include <memory.h>
#include <malloc.h>
#include <string.h>
#include <sys/types.h>
#if defined(sun) && defined(__GNUC__)
int socket(int,int,int);
int shutdown(int,int);
int close(int);
int bind(int,struct sockaddr*,int);
int listen(int,int);
void bzero(char*,int);
int select(int,fd_set *,fd_set*,fd_set*,struct timeval*);
int accept(int,struct sockaddr*,int*);
int connect(int,struct sockaddr*,int);
int recvfrom(int,char*,int,int,struct sockaddr*,int*);
/*void perror(char*); SLOWLARIS HASS*/
/*int sendto(int,char*,int,int,struct sockaddr*,int); SLOWLARIS HASS*/
#endif
/* extern char *sys_errlist[]; */
#ifdef hpux
/* redefinition... to avoid prototype in <time.h> */
#define FD_CAST int
#endif
#ifdef sgi
void bzero(void*,int);
#endif
#ifndef FD_CAST
#define FD_CAST fd_set
#endif
extern int errno;
char *inbuf[MAXUSERS],*outbuf[MAXUSERS];
int insize[MAXUSERS],outsize[MAXUSERS];
int incur[MAXUSERS],outcur[MAXUSERS];
int outfd[MAXUSERS],infd[MAXUSERS];
struct sockaddr_in inaddr[MAXUSERS],outaddr[MAXUSERS];
#ifdef _WIN32
#define perror xperror
void xperror(char *str) {
fprintf(stderr,"%s: %d\n",str,GetLastError());
}
#endif
static int
fd_make_nonblocking(int fd) {
int isnonblock=0;
#ifdef FIONBIO
if (!isnonblock) {
int b;
b=1;
if (-1==ioctl(fd,FIONBIO,&b)) {
perror("ioctl FIONBIO");
} else
isnonblock=1;
}
#endif
#ifdef O_NDELAY
if (!isnonblock) {
int flags;
if (-1==(flags=fcntl(fd,F_GETFL))) {
perror("fcntl F_GETFL");
} else {
flags|=O_NDELAY;
if (-1==fcntl(fd,F_SETFL,flags)) {
perror("fcntl F_SETFL O_NDELAY");
} else
isnonblock=1;
}
}
#endif
#ifdef O_NONBLOCK
if (!isnonblock) {
int flags;
if (-1==(flags=fcntl(fd,F_GETFL))) {
perror("fcntl F_GETFL");
} else {
flags|=O_NONBLOCK;
if (-1==fcntl(fd,F_SETFL,flags)) {
perror("fcntl F_SETFL O_NONBLOCK");
} else
isnonblock=1;
}
}
#endif
return isnonblock;
}
void
clean_connection(i)
int i;
{
if (outfd[i]>=0) {
if (-1==close(outfd[i]))
perror("close");
outfd[i]=-1;
}
if (infd[i]>=0) {
if (-1==close(infd[i]))
perror("close");
infd[i]=-1;
}
incur[i]=outcur[i]=0;
outbuf[i][0]=inbuf[i][0]='\0';
}
void
usage() {
fprintf(stderr,"Usage: relayd <listenport> <targethost> [<targetport>]\n");
}
void
main(argc,argv)
int argc;
char **argv;
{
int i,j,res;
int acfd;
struct sockaddr_in acsa;
char readbuf[1000],relaystring[1000];
struct in_addr targetaddr;
struct hostent *hp;
char *targethost;
int port,targetport;
#ifdef _WIN32
{
WSADATA wsad;
WSAStartup(0x0101,&wsad);
}
#else
close(0);
close(1);
#endif
#ifdef SIGPIPE
signal(SIGPIPE,SIG_IGN);
#endif
switch (argc) {
default:
case 1:
case 2:
usage();
exit(1);
case 3:
if (!sscanf(argv[1],"%d",&port)) {
usage();
exit(1);
}
targethost = argv[2];
targetport = 23;
break;
case 4:
if (!sscanf(argv[1],"%d",&port)) {
usage();exit(1);
}
if (!sscanf(argv[3],"%d",&targetport)) {
usage();exit(1);
}
targethost=argv[2];
break;
}
strcpy(relaystring,FAILMESSAGE);
if (-1==(acfd=socket(PF_INET,SOCK_STREAM,0))) {
perror("socket(accept_socket)");
exit(1);
}
for (i=MAXUSERS;i--;) {
inbuf[i]=malloc(10000*sizeof(char));
outbuf[i]=malloc(10000*sizeof(char));
inbuf[i][0]='\0';outbuf[i][0]='\0';
insize[i]=10000;incur[i]=0;
outsize[i]=10000;outcur[i]=0;
outfd[i]=infd[i]=-1;
}
acsa.sin_family=AF_INET;
acsa.sin_port=htons(port);
acsa.sin_addr.s_addr=INADDR_ANY;
if (-1==bind(acfd,(struct sockaddr*)&acsa,sizeof(struct sockaddr_in))) {
perror("bind");
exit(1);
}
/* 5 is usual the maximum anyway */
if (-1==listen(acfd,5)) {
perror("listen");
exit(1);
}
while (1) {
fd_set readfds,writefds;
int width;
width=3;
if (acfd>=width)
width=acfd+1;
restart_select:
FD_ZERO(&readfds);FD_ZERO(&writefds);
FD_SET(acfd,&readfds);
for (i=MAXUSERS;i--;) {
if (outfd[i]>=0) {
/*need to do that... else it will cause load 1*/
if (incur[i])
FD_SET(outfd[i],&writefds);
FD_SET(outfd[i],&readfds);
if (outfd[i]>=width)
width=outfd[i]+1;
}
if (infd[i]>=0) {
/*need to do that... else it will cause load 1*/
if (outcur[i])
FD_SET(infd[i],&writefds);
FD_SET(infd[i],&readfds);
if (infd[i]>=width)
width=infd[i]+1;
}
}
if (-1==select( width,
(FD_CAST*)&readfds,
(FD_CAST*)&writefds,
NULL,/*no exceptfds.*/
0)
) {
if (errno!=EINTR)
perror("select");
else
goto restart_select;
}
if (FD_ISSET(acfd,&readfds)) {
int afd;
int aclen;
struct sockaddr_in conaddr;
aclen=sizeof(struct sockaddr_in);
if (-1==(afd=accept(acfd,(struct sockaddr*)&conaddr,&aclen)))
perror("accept");
for (i=MAXUSERS;i--;)
if ((infd[i]==-1) && (outfd[i]==-1))
break;
if (i==-1) {
write(afd,relaystring,strlen(relaystring));
close(afd);
} else {
char sendbuf[200];
infd[i]=afd;
memcpy(&inaddr[i],&conaddr,sizeof(struct sockaddr_in));
/* outfd setting delayed until we get
* to the first line
*/
hp=gethostbyname(targethost);
if (!hp) {/* not found */
clean_connection(i);
continue;
}
memcpy(&targetaddr,hp->h_addr_list[0],sizeof(struct in_addr));
outaddr[i].sin_family=AF_INET;
outaddr[i].sin_port=htons(targetport);
memcpy(&(outaddr[i].sin_addr),&targetaddr,4);
strcpy(sendbuf,RELAYHEADER);
outcur[i]=strlen(sendbuf);
memcpy(outbuf[i],sendbuf,strlen(sendbuf)+1);
if (-1==(outfd[i]=socket(PF_INET,SOCK_STREAM,0)))
perror("socket(connect_socket)");
#ifndef _WIN32
(void)fd_make_nonblocking(outfd[i]);
#endif
if ( (-1==connect( outfd[i],
(struct sockaddr*)&outaddr[i],
sizeof(struct sockaddr_in))
#ifdef _WIN32
) && (WSAGetLastError()!=WSAEWOULDBLOCK)
#else
) && (errno!=EINPROGRESS)
#endif
) {
#ifdef _WIN32
sprintf(readbuf,"Connect to %s failed: %d\n",targethost,GetLastError());
#else
sprintf(readbuf,"Connect to %s failed: %s\n",targethost,sys_errlist[errno]);
#endif
perror("connect");
if (-1==write(infd[i],readbuf,strlen(readbuf)))
perror("write");
clean_connection(i);
continue;
}
inbuf[i][0]='\0';
incur[i]=0;
}
}
for (i=MAXUSERS;i--;) {
if ((infd[i]>=0) && FD_ISSET(infd[i],&readfds)) {
do {
if (-1==(res=read(infd[i],readbuf,1000))) {
if (errno==EINTR)
continue;
/* user side has broken the connection */
clean_connection(i);
break;
}
break;
} while (1);
if (res==0) /* EOF */
clean_connection(i);
if (res>0) {
readbuf[res]='\0';
while (incur[i]+res>=insize[i]) {
inbuf[i]=realloc(inbuf[i],insize[i]*2);
insize[i]*=2;
}
memcpy(inbuf[i]+incur[i],readbuf,res+1);
incur[i]+=res;
}
}
if ((outfd[i]>=0) && FD_ISSET(outfd[i],&readfds)) {
do {
if (-1==(res=read(outfd[i],readbuf,1000))) {
if (errno==EINTR)
continue;
/* the mudside has broken the
* connection. we still have
* to transmit the rest of
* the text
*/
outfd[i]=-1;
break;
}
break;
} while (1);
if (res==0)
clean_connection(i);
if (res>0) {
/* 0 is not automagically appended. */
readbuf[res]='\0';
while (outcur[i]+res>=outsize[i]) {
outbuf[i]=realloc(outbuf[i],outsize[i]*2);
outsize[i]*=2;
}
memcpy(outbuf[i]+outcur[i],readbuf,res+1);
outcur[i]+=res;
}
}
if ((infd[i]>=0) && FD_ISSET(infd[i],&writefds)) {
j=outcur[i];
if (-1==(res=write(infd[i],outbuf[i],j))) {
if (errno!=EINTR) {
clean_connection(i);
}
}
if (res>0) {
memcpy(outbuf[i],outbuf[i]+res,outcur[i]-res);
outcur[i]-=res;
}
}
if ((outfd[i]>=0) && FD_ISSET(outfd[i],&writefds)) {
j=incur[i];
if (-1==(res=write(outfd[i],inbuf[i],j))) {
if (errno!=EINTR) {
outfd[i]=-1;
/*clean_connection(i);*/
}
}
if (res>0) {
memcpy(inbuf[i],inbuf[i]+res,incur[i]-res);
incur[i]-=res;
}
}
}
}
}
