1 files changed, 315 insertions, 0 deletions
diff --git a/samples/proxy.c b/samples/proxy.c
new file mode 100644
index 0000000..f2063ec
--- /dev/null
+++ b/samples/proxy.c
@@ -0,0 +1,315 @@
+/*
+ * 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"
+#include "netinet/ipl.h"
+
+
+main(argc, argv)
+int argc;
+char *argv[];
+{
+	struct	sockaddr_in	sin, sloc, sout;
+	ipfobj_t	obj;
+	natlookup_t	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);
+	}
+
+	bzero((char *)&obj, sizeof(obj));
+	obj.ipfo_rev = IPFILTER_VERSION;
+	obj.ipfo_size = sizeof(natlook);
+	obj.ipfo_ptr = &natlook;
+	obj.ipfo_type = IPFOBJ_NATLOOKUP;
+
+	/*
+	 * 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_TCP;
+	natlook.nl_outport = sin.sin_port;
+	natlook.nl_inport = sloc.sin_port;
+
+	/*
+	 * Open the NAT device and lookup the mapping pair.
+	 */
+	fd = open(IPNAT_NAME, O_RDONLY);
+	if (ioctl(fd, SIOCGNATL, &obj) == -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;
+	ipfobj_t obj;
+	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_ifnames[0], extif,
+			sizeof(nat->nat_ifnames[0]));
+		strncpy(nat->nat_ifnames[1], extif,
+			sizeof(nat->nat_ifnames[1]));
+		nat->nat_ifnames[0][sizeof(nat->nat_ifnames[0]) - 1] = '\0';
+		nat->nat_ifnames[1][sizeof(nat->nat_ifnames[1]) - 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;
+
+	bzero((char *)&obj, sizeof(obj));
+	obj.ipfo_rev = IPFILTER_VERSION;
+	obj.ipfo_size = sizeof(*nsp);
+	obj.ipfo_ptr = nsp;
+	obj.ipfo_type = IPFOBJ_NATSAVE;
+
+	onoff = 1;
+	if (ioctl(fd, SIOCSTLCK, &onoff) == 0) {
+		if (ioctl(fd, SIOCSTPUT, &obj) != 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