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/*
* Copyright (C) 1999/2000 Sebastian Krahmer.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Sebastian Krahmer.
* 4. The name Sebastian Krahmer may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "misc.h"
#include "socket.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
// since this is entered by new process each call
// we must make itextern and increased by main()
extern short inc;
namespace NS_Filter {
const char SSL_HANDSHAKE = 22;
const char SSL_MAJOR3 = 3;
const char SSL_CLIENTHELLO = 1;
unsigned short portbase = 8888;
using namespace NS_Misc;
void check_and_forward(int server)
{
struct sockaddr_in dst;
int client, r = 0;
// we are server. get real dest.
if (NS_Socket::dstaddr(server, &dst) < 0) {
log(NS_Socket::why());
die(NULL);
}
// calc. port to bind to
unsigned short port = portbase + (inc++ % (65000-portbase));
// make connection to real server
if ((client = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
log("NS_Filter::check_and_forward::socket");
die(NULL);
}
fd_set rset;
FD_ZERO(&rset);
FD_SET(server, &rset);
struct timeval tv;
tv.tv_sec = 2;
tv.tv_usec = 0;
// watch if real client sends some data
if (select(server+1, &rset, NULL, NULL, &tv) < 0) {
log("NS_Filter::check_and_forward::select");
die(NULL);
}
char buf[4096];
memset(buf, 0, sizeof(buf));
// if so, check for SSLv3
if (FD_ISSET(server, &rset)) {
if ((r = read(server, buf, sizeof(buf))) < 0) {
log("NS_Filter::check_and_forward::read");
die(NULL);
}
if (buf[0] == SSL_HANDSHAKE &&
buf[1] == SSL_MAJOR3 &&
buf[5] == SSL_CLIENTHELLO &&
buf[9] == SSL_MAJOR3) { // got SSLv3 ?
// bind to special port to signal that
// SSL is coming
if (NS_Socket::bind_local(client, port, false) < 0) {
log(NS_Socket::why());
die(NULL);
}
log("Filtered SSL connection.");
}
}
// Now, do the connect, aftee we bound or not
if (connect(client, (struct sockaddr*)&dst, sizeof(dst)) < 0) {
log("NS_Filter::check_and_forward::connect");
die(NULL);
}
// If there was any data sent by client, flush it now
if (FD_ISSET(server, &rset))
write(client, buf, r);
int max = server > client ? server : client;
for (;;) {
// now, do the proxy
FD_ZERO(&rset);
FD_SET(server, &rset);
FD_SET(client, &rset);
if (select(max+1, &rset, NULL, NULL, NULL) < 0) {
if (errno == EINTR)
continue;
else {
log("NS_Filter::check_and_forward::select()");
die(NULL);
}
}
if (FD_ISSET(client, &rset)) {
r = read(client, buf, sizeof(buf));
if (r <= 0)
break;
if (write(server, buf, r) < 0)
break;
}
if (FD_ISSET(server, &rset)) {
errno = 0;
r = read(server, buf, sizeof(buf));
if (r <= 0)
break;
if (write(client, buf, r) < 0)
break;
}
}
close(client);
return;
}
}; // namespace
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