ref: 928de2ce5c6140c19c348ad782bfbe5fa6e35fc4
dir: /QW/qwfwd/qwfwd.c/
/*
Copyright (C) 1996-1997 Id Software, Inc.
This program 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
of the License, or (at your option) any later version.
This program 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 program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* udpred - a inetd launched udp port redirector
*
* Version: @(#)udpred.c 0.01 01/15/97
*
* Author: Chris Faherty <chrisf@america.com>
*
* syntax:
*
* udpred toip toport
*
* sample inetd.conf entry:
*
* 7000 dgram udp wait root /usr/sbin/tcpd /usr/sbin/udpred 192.168.100.16 7000
*
*
* This program 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 of the License, or (at your option) any later version.
*
*/
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/types.h>
#include <time.h>
#ifdef _WIN32
#include <winsock.h>
#else
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netdb.h>
#include <netinet/in.h>
#include <unistd.h>
#include <syslog.h>
#endif
int host_port; // port we are listening on
typedef struct peer {
time_t last;
struct sockaddr_in sin;
struct sockaddr_in dest;
int s; // connected socket to remote
struct peer *next;
} peer_t;
peer_t *peers;
/*
====================
NET_Init
====================
*/
void NET_Init (void)
{
#ifdef _WIN32
static WSADATA winsockdata;
// WORD wVersionRequested;
int r;
// wVersionRequested = MAKEWORD(1, 1);
r = WSAStartup (MAKEWORD(2, 1), &winsockdata);
if (r) {
fprintf(stderr, "Winsock initialization failed.");
exit(1);
}
printf("Winsock Initialized\n");
#endif
}
int connectsock(char *host, char *service, char *protocol)
{
struct hostent *phe;
struct servent *pse;
struct protoent *ppe;
struct sockaddr_in sin;
int s, type;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
/* Map service name to port number */
if(pse = getservbyname(service, protocol))
sin.sin_port = pse->s_port;
else if((sin.sin_port = htons((u_short)atoi(service))) == 0)
{
fprintf(stderr, "udpred: can't get \"%s\" service entry\n", service);
exit(2);
}
/* Map host name to IP address, allowing for dotted decimal */
if(phe = gethostbyname(host))
memcpy((char *)&sin.sin_addr, phe->h_addr, phe->h_length);
else if((sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE)
{
fprintf(stderr, "udpred: can't get \"%s\" host entry\n", host);
exit(2);
}
/* Map protocol name to protocol number */
if((ppe = getprotobyname(protocol)) == 0)
{
fprintf(stderr, "udpred: can't get \"%s\" protocol entry\n", protocol);
exit(2);
}
/* Use protocol to choose a socket type */
if(strcmp(protocol, "udp") == 0)
type = SOCK_DGRAM;
else
type = SOCK_STREAM;
/* Allocate a socket */
s = socket(PF_INET, type, ppe->p_proto);
if(s < 0)
{
fprintf(stderr, "udpred: can't create socket: %s\n", sys_errlist[errno]);
exit(2);
}
/* Connect the socket */
if(connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
{
fprintf(stderr, "udpred: can't connect to %s.%s: %s\n", host, service, sys_errlist[errno]);
exit(2);
}
return s;
}
int main(int argc, char *argv[])
{
fd_set rfds;
struct timeval tv;
int retval;
int i1;
char buffer[4095];
struct sockaddr_in fsin;
int alen;
peer_t *p;
int s;
struct sockaddr_in address;
if (argc < 3) {
printf("Usage: %s <port> <remote server> <remote server port>\n", argv[0]);
return 1;
}
NET_Init();
if ((s = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
perror("socket");
return 1;
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons((unsigned short)atoi(argv[1]));
if (bind (s, (void *)&address, sizeof(address)) == -1)
perror("bind");
while(1)
{
FD_ZERO(&rfds);
FD_SET(s, &rfds);
i1 = s;
for (p = peers; p; p = p->next) {
FD_SET(p->s, &rfds);
if (p->s >= i1)
i1 = p->s + 1;
}
/* Wait up to two minutes. */
tv.tv_sec = 2;
tv.tv_usec = 0;
retval = select(i1, &rfds, (fd_set *)0, (fd_set *)0, &tv);
if(retval > 0)
{
if(FD_ISSET(s, &rfds))
{
alen = sizeof(fsin);
i1 = recvfrom(s, buffer, 4096, 0, (struct sockaddr *) &fsin, &alen);
if(i1 > 0) {
for (p = peers; p; p = p->next)
if (memcmp(&p->sin.sin_addr, &fsin.sin_addr, sizeof(p->sin.sin_addr)) == 0 &&
memcmp(&p->sin.sin_port, &fsin.sin_port, sizeof(p->sin.sin_port)) == 0)
{
send(p->s, buffer, i1, 0);
time(&p->last);
break;
}
if (p == NULL) { // new peer
printf("peer %s:%d added", inet_ntoa(fsin.sin_addr), (int)ntohs(fsin.sin_port));
p = malloc(sizeof *p);
p->sin = fsin;
p->s = connectsock(argv[2], argv[3], "udp");
p->next = peers;
peers = p;
send(p->s, buffer, i1, 0);
time(&p->last);
}
}
}
for (p = peers; p; p = p->next)
if(FD_ISSET(p->s, &rfds))
{
i1 = recv(p->s, buffer, 4096, 0);
if(i1 > 0) {
time(&p->last);
sendto(s, buffer, i1, 0, (struct sockaddr *) &p->sin,
sizeof(p->sin));
}
}
} else {
peer_t *pp;
pp = NULL;
p = peers;
while (p) {
if (time(NULL) - p->last > 300) {
if (!pp && !p->next) {
printf("peer %s:%d removed (timeout)", inet_ntoa(p->sin.sin_addr), (int)ntohs(p->sin.sin_port));
free(p);
p = pp = NULL;
continue;
}
pp->next = p->next;
printf ("peer %s:%d removed (timeout)", inet_ntoa(p->sin.sin_addr), (int)ntohs(p->sin.sin_port));
free(p);
p = pp->next;
} else {
pp = p;
p = p->next;
}
}
}
}
}