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