samples/proxy.c - net/ipfilter - Rivoreo Source Code Repositories

 /*
  * Sample transparent proxy program.
  *
  * Sample implementation of a program which intercepts a TCP connectiona and
  * just echos all data back to the origin.  Written to work via inetd as a
  * "nonwait" program running as root; ie.
  * tcpmux          stream  tcp     nowait root /usr/local/bin/proxy proxy
  * with a NAT rue like this:
  * rdr smc0 0/0 port 80 -> 127.0.0.1/32 port 1
  */
 #include <stdio.h>
 #include <string.h>
 #include <fcntl.h>
 #include <syslog.h>
 #if !defined(__SVR4) && !defined(__svr4__)
 #include <strings.h>
 #else
 #include <sys/byteorder.h>
 #endif
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/param.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <stddef.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #if defined(sun) && (defined(__svr4__) || defined(__SVR4))
 # include <sys/ioccom.h>
 # include <sys/sysmacros.h>
 #endif
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
 #include <net/if.h>
 #include <netdb.h>
 #include <arpa/nameser.h>
 #include <arpa/inet.h>
 #include <resolv.h>
 #include <ctype.h>
 #include "netinet/ip_compat.h"
 #include "netinet/ip_fil.h"
 #include "netinet/ip_nat.h"
 #include "netinet/ip_state.h"
 #include "netinet/ip_proxy.h"
 #include "netinet/ip_nat.h"


 main(argc, argv)
 int argc;
 char *argv[];
 {
 	struct	sockaddr_in	sin, sloc, sout;
 	natlookup_t	natlook;
 	natlookup_t	*natlookp = &natlook;
 	char	buffer[512];
 	int	namelen, fd, n;

 	/*
 	 * get IP# and port # of the remote end of the connection (at the
 	 * origin).
 	 */
 	namelen = sizeof(sin);
 	if (getpeername(0, (struct sockaddr *)&sin, &namelen) == -1) {
 		perror("getpeername");
 		exit(-1);
 	}

 	/*
 	 * get IP# and port # of the local end of the connection (at the
 	 * man-in-the-middle).
 	 */
 	namelen = sizeof(sin);
 	if (getsockname(0, (struct sockaddr *)&sloc, &namelen) == -1) {
 		perror("getsockname");
 		exit(-1);
 	}

 	/*
 	 * Build up the NAT natlookup structure.
 	 */
 	bzero((char *)&natlook, sizeof(natlook));
 	natlook.nl_outip = sin.sin_addr;
 	natlook.nl_inip = sloc.sin_addr;
 	natlook.nl_flags = IPN_TCPUDP;
 	natlook.nl_outport = ntohs(sin.sin_port);
 	natlook.nl_inport = ntohs(sloc.sin_port);

 	/*
 	 * Open the NAT device and lookup the mapping pair.
 	 */
 	fd = open(IPL_NAT, O_RDONLY);
 	if (ioctl(fd, SIOCGNATL, &natlookp) == -1) {
 		perror("ioctl(SIOCGNATL)");
 		exit(-1);
 	}

 #define	DO_NAT_OUT
 #ifdef	DO_NAT_OUT
 	if (argc > 1)
 		do_nat_out(0, 1, fd, &natlook, argv[1]);
 #else

 	/*
 	 * Log it
 	 */
 	syslog(LOG_DAEMON|LOG_INFO, "connect to %s,%d",
 		inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));
 	printf("connect to %s,%d\n",
 		inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));

 	/*
 	 * Just echo data read in from stdin to stdout
 	 */
 	while ((n = read(0, buffer, sizeof(buffer))) > 0)
 		if (write(1, buffer, n) != n)
 			break;
 	close(0);
 #endif
 }


 #ifdef	DO_NAT_OUT
 do_nat_out(in, out, fd, nlp, extif)
 int fd;
 natlookup_t *nlp;
 char *extif;
 {
 	nat_save_t ns, *nsp = &ns;
 	struct sockaddr_in usin;
 	u_32_t sum1, sum2, sumd;
 	int onoff, ofd, slen;
 	ipnat_t *ipn;
 	nat_t *nat;

 	bzero((char *)&ns, sizeof(ns));

 	nat = &ns.ipn_nat;
 	nat->nat_p = IPPROTO_TCP;
 	nat->nat_dir = NAT_OUTBOUND;
 	if ((extif != NULL) && (*extif != '\0')) {
 		strncpy(nat->nat_ifname, extif, sizeof(nat->nat_ifname));
 		nat->nat_ifname[sizeof(nat->nat_ifname) - 1] = '\0';
 	}

 	ofd = socket(AF_INET, SOCK_DGRAM, 0);
 	bzero((char *)&usin, sizeof(usin));
 	usin.sin_family = AF_INET;
 	usin.sin_addr = nlp->nl_realip;
 	usin.sin_port = nlp->nl_realport;
 	(void) connect(ofd, (struct sockaddr *)&usin, sizeof(usin));
 	slen = sizeof(usin);
 	(void) getsockname(ofd, (struct sockaddr *)&usin, &slen);
 	close(ofd);
 printf("local IP# to use: %s\n", inet_ntoa(usin.sin_addr));

 	if ((ofd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
 		perror("socket");
 	usin.sin_port = 0;
 	if (bind(ofd, (struct sockaddr *)&usin, sizeof(usin)))
 		perror("bind");
 	slen = sizeof(usin);
 	if (getsockname(ofd, (struct sockaddr *)&usin, &slen))
 		perror("getsockname");
 printf("local port# to use: %d\n", ntohs(usin.sin_port));

 	nat->nat_inip = usin.sin_addr;
 	nat->nat_outip = nlp->nl_outip;
 	nat->nat_oip = nlp->nl_realip;

 	sum1 = LONG_SUM(ntohl(usin.sin_addr.s_addr)) + ntohs(usin.sin_port);
 	sum2 = LONG_SUM(ntohl(nat->nat_outip.s_addr)) + ntohs(nlp->nl_outport);
 	CALC_SUMD(sum1, sum2, sumd);
 	nat->nat_sumd[0] = (sumd & 0xffff) + (sumd >> 16);
 	nat->nat_sumd[1] = nat->nat_sumd[0];

 	sum1 = LONG_SUM(ntohl(usin.sin_addr.s_addr));
 	sum2 = LONG_SUM(ntohl(nat->nat_outip.s_addr));
 	CALC_SUMD(sum1, sum2, sumd);
 	nat->nat_ipsumd = (sumd & 0xffff) + (sumd >> 16);

 	nat->nat_inport = usin.sin_port;
 	nat->nat_outport = nlp->nl_outport;
 	nat->nat_oport = nlp->nl_realport;

 	nat->nat_flags = IPN_TCPUDP;

 	onoff = 1;
 	if (ioctl(fd, SIOCSTLCK, &onoff) == 0) {
 		if (ioctl(fd, SIOCSTPUT, &nsp) != 0)
 			perror("SIOCSTPUT");
 		onoff = 0;
 		if (ioctl(fd, SIOCSTLCK, &onoff) != 0)
 			perror("SIOCSTLCK");
 	}

 	usin.sin_addr = nlp->nl_realip;
 	usin.sin_port = nlp->nl_realport;
 printf("remote end for connection: %s,%d\n", inet_ntoa(usin.sin_addr),
 ntohs(usin.sin_port));
 fflush(stdout);
 	if (connect(ofd, (struct sockaddr *)&usin, sizeof(usin)))
 		perror("connect");

 	relay(in, out, ofd);
 }


 relay(in, out, net)
 int in, out, net;
 {
 	char netbuf[1024], outbuf[1024];
 	char *nwptr, *nrptr, *owptr, *orptr;
 	size_t nsz, osz;
 	fd_set rd, wr;
 	int i, n, maxfd;

 	n = 0;
 	maxfd = in;
 	if (out > maxfd)
 		maxfd = out;
 	if (net > maxfd)
 		maxfd = net;

 	nrptr = netbuf;
 	nwptr = netbuf;
 	nsz = sizeof(netbuf);
 	orptr = outbuf;
 	owptr = outbuf;
 	osz = sizeof(outbuf);

 	while (n >= 0) {
 		FD_ZERO(&rd);
 		FD_ZERO(&wr);

 		if (nrptr - netbuf < sizeof(netbuf))
 			FD_SET(in, &rd);
 		if (orptr - outbuf < sizeof(outbuf))
 			FD_SET(net, &rd);

 		if (nsz < sizeof(netbuf))
 			FD_SET(net, &wr);
 		if (osz < sizeof(outbuf))
 			FD_SET(out, &wr);

 		n = select(maxfd + 1, &rd, &wr, NULL, NULL);

 		if ((n > 0) && FD_ISSET(in, &rd)) {
 			i = read(in, nrptr, sizeof(netbuf) - (nrptr - netbuf));
 			if (i <= 0)
 				break;
 			nsz -= i;
 			nrptr += i;
 			n--;
 		}

 		if ((n > 0) && FD_ISSET(net, &rd)) {
 			i = read(net, orptr, sizeof(outbuf) - (orptr - outbuf));
 			if (i <= 0)
 				break;
 			osz -= i;
 			orptr += i;
 			n--;
 		}

 		if ((n > 0) && FD_ISSET(out, &wr)) {
 			i = write(out, owptr, orptr - owptr);
 			if (i <= 0)
 				break;
 			osz += i;
 			if (osz == sizeof(outbuf) || owptr == orptr) {
 				orptr = outbuf;
 				owptr = outbuf;
 			} else
 				owptr += i;
 			n--;
 		}

 		if ((n > 0) && FD_ISSET(net, &wr)) {
 			i = write(net, nwptr, nrptr - nwptr);
 			if (i <= 0)
 				break;
 			nsz += i;
 			if (nsz == sizeof(netbuf) || nwptr == nrptr) {
 				nrptr = netbuf;
 				nwptr = netbuf;
 			} else
 				nwptr += i;
 		}
 	}

 	close(net);
 	close(out);
 	close(in);
 }
 #endif
	/*
	* Sample transparent proxy program.
	*
	* Sample implementation of a program which intercepts a TCP connectiona and
	* just echos all data back to the origin. Written to work via inetd as a
	* "nonwait" program running as root; ie.
	* tcpmux stream tcp nowait root /usr/local/bin/proxy proxy
	* with a NAT rue like this:
	* rdr smc0 0/0 port 80 -> 127.0.0.1/32 port 1
	*/
	#include <stdio.h>
	#include <string.h>
	#include <fcntl.h>
	#include <syslog.h>
	#if !defined(__SVR4) && !defined(__svr4__)
	#include <strings.h>
	#else
	#include <sys/byteorder.h>
	#endif
	#include <sys/types.h>
	#include <sys/time.h>
	#include <sys/param.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <stddef.h>
	#include <sys/socket.h>
	#include <sys/ioctl.h>
	#if defined(sun) && (defined(__svr4__) \|\| defined(__SVR4))
	# include <sys/ioccom.h>
	# include <sys/sysmacros.h>
	#endif
	#include <netinet/in.h>
	#include <netinet/in_systm.h>
	#include <netinet/ip.h>
	#include <netinet/tcp.h>
	#include <net/if.h>
	#include <netdb.h>
	#include <arpa/nameser.h>
	#include <arpa/inet.h>
	#include <resolv.h>
	#include <ctype.h>
	#include "netinet/ip_compat.h"
	#include "netinet/ip_fil.h"
	#include "netinet/ip_nat.h"
	#include "netinet/ip_state.h"
	#include "netinet/ip_proxy.h"
	#include "netinet/ip_nat.h"


	main(argc, argv)
	int argc;
	char *argv[];
	{
	struct sockaddr_in sin, sloc, sout;
	natlookup_t natlook;
	natlookup_t *natlookp = &natlook;
	char buffer[512];
	int namelen, fd, n;

	/*
	* get IP# and port # of the remote end of the connection (at the
	* origin).
	*/
	namelen = sizeof(sin);
	if (getpeername(0, (struct sockaddr *)&sin, &namelen) == -1) {
	perror("getpeername");
	exit(-1);
	}

	/*
	* get IP# and port # of the local end of the connection (at the
	* man-in-the-middle).
	*/
	namelen = sizeof(sin);
	if (getsockname(0, (struct sockaddr *)&sloc, &namelen) == -1) {
	perror("getsockname");
	exit(-1);
	}

	/*
	* Build up the NAT natlookup structure.
	*/
	bzero((char *)&natlook, sizeof(natlook));
	natlook.nl_outip = sin.sin_addr;
	natlook.nl_inip = sloc.sin_addr;
	natlook.nl_flags = IPN_TCPUDP;
	natlook.nl_outport = ntohs(sin.sin_port);
	natlook.nl_inport = ntohs(sloc.sin_port);

	/*
	* Open the NAT device and lookup the mapping pair.
	*/
	fd = open(IPL_NAT, O_RDONLY);
	if (ioctl(fd, SIOCGNATL, &natlookp) == -1) {
	perror("ioctl(SIOCGNATL)");
	exit(-1);
	}

	#define DO_NAT_OUT
	#ifdef DO_NAT_OUT
	if (argc > 1)
	do_nat_out(0, 1, fd, &natlook, argv[1]);
	#else

	/*
	* Log it
	*/
	syslog(LOG_DAEMON\|LOG_INFO, "connect to %s,%d",
	inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));
	printf("connect to %s,%d\n",
	inet_ntoa(natlook.nl_realip), ntohs(natlook.nl_realport));

	/*
	* Just echo data read in from stdin to stdout
	*/
	while ((n = read(0, buffer, sizeof(buffer))) > 0)
	if (write(1, buffer, n) != n)
	break;
	close(0);
	#endif
	}


	#ifdef DO_NAT_OUT
	do_nat_out(in, out, fd, nlp, extif)
	int fd;
	natlookup_t *nlp;
	char *extif;
	{
	nat_save_t ns, *nsp = &ns;
	struct sockaddr_in usin;
	u_32_t sum1, sum2, sumd;
	int onoff, ofd, slen;
	ipnat_t *ipn;
	nat_t *nat;

	bzero((char *)&ns, sizeof(ns));

	nat = &ns.ipn_nat;
	nat->nat_p = IPPROTO_TCP;
	nat->nat_dir = NAT_OUTBOUND;
	if ((extif != NULL) && (*extif != '\0')) {
	strncpy(nat->nat_ifname, extif, sizeof(nat->nat_ifname));
	nat->nat_ifname[sizeof(nat->nat_ifname) - 1] = '\0';
	}

	ofd = socket(AF_INET, SOCK_DGRAM, 0);
	bzero((char *)&usin, sizeof(usin));
	usin.sin_family = AF_INET;
	usin.sin_addr = nlp->nl_realip;
	usin.sin_port = nlp->nl_realport;
	(void) connect(ofd, (struct sockaddr *)&usin, sizeof(usin));
	slen = sizeof(usin);
	(void) getsockname(ofd, (struct sockaddr *)&usin, &slen);
	close(ofd);
	printf("local IP# to use: %s\n", inet_ntoa(usin.sin_addr));

	if ((ofd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	perror("socket");
	usin.sin_port = 0;
	if (bind(ofd, (struct sockaddr *)&usin, sizeof(usin)))
	perror("bind");
	slen = sizeof(usin);
	if (getsockname(ofd, (struct sockaddr *)&usin, &slen))
	perror("getsockname");
	printf("local port# to use: %d\n", ntohs(usin.sin_port));

	nat->nat_inip = usin.sin_addr;
	nat->nat_outip = nlp->nl_outip;
	nat->nat_oip = nlp->nl_realip;

	sum1 = LONG_SUM(ntohl(usin.sin_addr.s_addr)) + ntohs(usin.sin_port);
	sum2 = LONG_SUM(ntohl(nat->nat_outip.s_addr)) + ntohs(nlp->nl_outport);
	CALC_SUMD(sum1, sum2, sumd);
	nat->nat_sumd[0] = (sumd & 0xffff) + (sumd >> 16);
	nat->nat_sumd[1] = nat->nat_sumd[0];

	sum1 = LONG_SUM(ntohl(usin.sin_addr.s_addr));
	sum2 = LONG_SUM(ntohl(nat->nat_outip.s_addr));
	CALC_SUMD(sum1, sum2, sumd);
	nat->nat_ipsumd = (sumd & 0xffff) + (sumd >> 16);

	nat->nat_inport = usin.sin_port;
	nat->nat_outport = nlp->nl_outport;
	nat->nat_oport = nlp->nl_realport;

	nat->nat_flags = IPN_TCPUDP;

	onoff = 1;
	if (ioctl(fd, SIOCSTLCK, &onoff) == 0) {
	if (ioctl(fd, SIOCSTPUT, &nsp) != 0)
	perror("SIOCSTPUT");
	onoff = 0;
	if (ioctl(fd, SIOCSTLCK, &onoff) != 0)
	perror("SIOCSTLCK");
	}

	usin.sin_addr = nlp->nl_realip;
	usin.sin_port = nlp->nl_realport;
	printf("remote end for connection: %s,%d\n", inet_ntoa(usin.sin_addr),
	ntohs(usin.sin_port));
	fflush(stdout);
	if (connect(ofd, (struct sockaddr *)&usin, sizeof(usin)))
	perror("connect");

	relay(in, out, ofd);
	}


	relay(in, out, net)
	int in, out, net;
	{
	char netbuf[1024], outbuf[1024];
	char nwptr, nrptr, owptr, orptr;
	size_t nsz, osz;
	fd_set rd, wr;
	int i, n, maxfd;

	n = 0;
	maxfd = in;
	if (out > maxfd)
	maxfd = out;
	if (net > maxfd)
	maxfd = net;

	nrptr = netbuf;
	nwptr = netbuf;
	nsz = sizeof(netbuf);
	orptr = outbuf;
	owptr = outbuf;
	osz = sizeof(outbuf);

	while (n >= 0) {
	FD_ZERO(&rd);
	FD_ZERO(&wr);

	if (nrptr - netbuf < sizeof(netbuf))
	FD_SET(in, &rd);
	if (orptr - outbuf < sizeof(outbuf))
	FD_SET(net, &rd);

	if (nsz < sizeof(netbuf))
	FD_SET(net, &wr);
	if (osz < sizeof(outbuf))
	FD_SET(out, &wr);

	n = select(maxfd + 1, &rd, &wr, NULL, NULL);

	if ((n > 0) && FD_ISSET(in, &rd)) {
	i = read(in, nrptr, sizeof(netbuf) - (nrptr - netbuf));
	if (i <= 0)
	break;
	nsz -= i;
	nrptr += i;
	n--;
	}

	if ((n > 0) && FD_ISSET(net, &rd)) {
	i = read(net, orptr, sizeof(outbuf) - (orptr - outbuf));
	if (i <= 0)
	break;
	osz -= i;
	orptr += i;
	n--;
	}

	if ((n > 0) && FD_ISSET(out, &wr)) {
	i = write(out, owptr, orptr - owptr);
	if (i <= 0)
	break;
	osz += i;
	if (osz == sizeof(outbuf) \|\| owptr == orptr) {
	orptr = outbuf;
	owptr = outbuf;
	} else
	owptr += i;
	n--;
	}

	if ((n > 0) && FD_ISSET(net, &wr)) {
	i = write(net, nwptr, nrptr - nwptr);
	if (i <= 0)
	break;
	nsz += i;
	if (nsz == sizeof(netbuf) \|\| nwptr == nrptr) {
	nrptr = netbuf;
	nwptr = netbuf;
	} else
	nwptr += i;
	}
	}

	close(net);
	close(out);
	close(in);
	}
	#endif