114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/* $NetBSD: proxy.c,v 1.1.1.1 1999/12/11 22:24:12 veego Exp $ */
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/*
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* Sample transparent proxy program.
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*
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* Sample implementation of a program which intercepts a TCP connectiona and
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* just echos all data back to the origin. Written to work via inetd as a
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* "nonwait" program running as root; ie.
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* tcpmux stream tcp nowait root /usr/local/bin/proxy proxy
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* with a NAT rue like this:
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* rdr smc0 0/0 port 80 -> 127.0.0.1/32 port 1
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*/
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <syslog.h>
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#if !defined(__SVR4) && !defined(__svr4__)
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#include <strings.h>
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#else
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#include <sys/byteorder.h>
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#endif
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/param.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#if defined(sun) && (defined(__svr4__) || defined(__SVR4))
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# include <sys/ioccom.h>
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# include <sys/sysmacros.h>
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#endif
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/tcp.h>
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#include <net/if.h>
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#include <netdb.h>
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#include <arpa/nameser.h>
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#include <arpa/inet.h>
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#include <resolv.h>
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#include <ctype.h>
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#include "netinet/ip_compat.h"
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#include "netinet/ip_fil.h"
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#include "netinet/ip_proxy.h"
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#include "netinet/ip_nat.h"
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main(argc, argv)
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int argc;
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char *argv[];
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{
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struct sockaddr_in sin, sloc, sout;
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natlookup_t natlook;
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char buffer[512];
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int namelen, fd, n;
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/*
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* get IP# and port # of the remote end of the connection (at the
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* origin).
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*/
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namelen = sizeof(sin);
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if (getpeername(0, (struct sockaddr *)&sin, &namelen) == -1) {
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perror("getpeername");
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exit(-1);
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}
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/*
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* get IP# and port # of the local end of the connection (at the
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* man-in-the-middle).
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*/
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namelen = sizeof(sin);
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if (getsockname(0, (struct sockaddr *)&sloc, &namelen) == -1) {
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perror("getsockname");
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exit(-1);
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}
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/*
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* Build up the NAT natlookup structure.
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*/
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bzero((char *)&natlook, sizeof(natlook));
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natlook.nl_outip = sin.sin_addr;
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natlook.nl_inip = sloc.sin_addr;
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natlook.nl_flags = IPN_TCP;
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natlook.nl_outport = sin.sin_port;
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natlook.nl_inport = sloc.sin_port;
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/*
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* Open the NAT device and lookup the mapping pair.
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*/
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fd = open(IPL_NAT, O_RDONLY);
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if (ioctl(fd, SIOCGNATL, &natlook) == -1) {
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perror("ioctl");
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exit(-1);
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}
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close(fd);
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/*
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* Log it
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*/
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syslog(LOG_DAEMON|LOG_INFO, "connect to %s,%d",
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inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));
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printf("connect to %s,%d\n",
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inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));
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/*
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* Just echo data read in from stdin to stdout
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*/
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while ((n = read(0, buffer, sizeof(buffer))) > 0)
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if (write(1, buffer, n) != n)
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break;
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close(0);
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}
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