/** * 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 */ /* 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 " or "relay " * 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 #ifdef _WIN32 #include #include #include #include #include #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 #include #include #include #include #include #include #include #include #include #endif #include #include #include #include #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 */ #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 []\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; } } } } }