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/***************************************************************************
* proxy_http.c -- HTTP Connect proxying. *
* *
***********************IMPORTANT NSOCK LICENSE TERMS***********************
*
* The nsock parallel socket event library is (C) 1999-2023 Nmap Software LLC
* This library is free software; you may redistribute and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; Version 2. This guarantees your right to use, modify, and
* redistribute this software under certain conditions. If this license is
* unacceptable to you, Nmap Software LLC may be willing to sell alternative
* licenses (contact sales@nmap.com ).
*
* As a special exception to the GPL terms, Nmap Software LLC grants permission
* to link the code of this program with any version of the OpenSSL library
* which is distributed under a license identical to that listed in the included
* docs/licenses/OpenSSL.txt file, and distribute linked combinations including
* the two. You must obey the GNU GPL in all respects for all of the code used
* other than OpenSSL. If you modify this file, you may extend this exception to
* your version of the file, but you are not obligated to do so.
*
* If you received these files with a written license agreement stating terms
* other than the (GPL) terms above, then that alternative license agreement
* takes precedence over this comment.
*
* Source is provided to this software because we believe users have a right to
* know exactly what a program is going to do before they run it. This also
* allows you to audit the software for security holes.
*
* Source code also allows you to port Nmap to new platforms, fix bugs, and add
* new features. You are highly encouraged to send your changes to the
* dev@nmap.org mailing list for possible incorporation into the main
* distribution. By sending these changes to Fyodor or one of the Insecure.Org
* development mailing lists, or checking them into the Nmap source code
* repository, it is understood (unless you specify otherwise) that you are
* offering the Nmap Project (Nmap Software LLC) the unlimited, non-exclusive
* right to reuse, modify, and relicense the code. Nmap will always be available
* Open Source, but this is important because the inability to relicense code
* has caused devastating problems for other Free Software projects (such as KDE
* and NASM). We also occasionally relicense the code to third parties as
* discussed above. If you wish to specify special license conditions of your
* contributions, just say so when you send them.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License v2.0 for more
* details (http://www.gnu.org/licenses/gpl-2.0.html).
*
***************************************************************************/
/* $Id $ */
#define _GNU_SOURCE
#include <stdio.h>
#include "nsock.h"
#include "nsock_internal.h"
#include "nsock_log.h"
#include <string.h>
#define DEFAULT_PROXY_PORT_HTTP 8080
extern struct timeval nsock_tod;
extern const struct proxy_spec ProxySpecHttp;
static int proxy_http_node_new(struct proxy_node **node, const struct uri *uri) {
int rc;
struct proxy_node *proxy;
proxy = (struct proxy_node *)safe_zalloc(sizeof(struct proxy_node));
proxy->spec = &ProxySpecHttp;
rc = proxy_resolve(uri->host, (struct sockaddr *)&proxy->ss, &proxy->sslen, AF_UNSPEC);
if (rc < 0) {
free(proxy);
*node = NULL;
return -1;
}
if (uri->port == -1)
proxy->port = DEFAULT_PROXY_PORT_HTTP;
else
proxy->port = (unsigned short)uri->port;
rc = asprintf(&proxy->nodestr, "http://%s:%d", uri->host, proxy->port);
if (rc < 0) {
/* asprintf() failed for some reason but this is not a disaster (yet).
* Set nodestr to NULL and try to keep on going. */
proxy->nodestr = NULL;
}
*node = proxy;
return 1;
}
static void proxy_http_node_delete(struct proxy_node *node) {
if (!node)
return;
free(node->nodestr);
free(node);
}
static int handle_state_initial(struct npool *nsp, struct nevent *nse, void *udata) {
struct proxy_chain_context *px_ctx = nse->iod->px_ctx;
struct sockaddr_storage *ss;
size_t sslen;
unsigned short port;
struct proxy_node *next;
int timeout;
px_ctx->px_state = PROXY_STATE_HTTP_TCP_CONNECTED;
next = proxy_ctx_node_next(px_ctx);
if (next) {
ss = &next->ss;
sslen = next->sslen;
port = next->port;
} else {
ss = &px_ctx->target_ss;
sslen = px_ctx->target_sslen;
port = px_ctx->target_port;
}
timeout = TIMEVAL_MSEC_SUBTRACT(nse->timeout, nsock_tod);
nsock_printf(nsp, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch,
timeout, udata, "CONNECT %s:%d HTTP/1.1\r\n\r\n",
inet_ntop_ez(ss, sslen), (int)port);
nsock_readlines(nsp, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch,
timeout, udata, 1);
return 0;
}
static int handle_state_tcp_connected(struct npool *nsp, struct nevent *nse, void *udata) {
struct proxy_chain_context *px_ctx = nse->iod->px_ctx;
char *res;
int reslen;
res = nse_readbuf(nse, &reslen);
/* TODO string check!! */
if (!((reslen >= 15) && strstr(res, "200 OK"))) {
struct proxy_node *node = px_ctx->px_current;
nsock_log_debug("Connection refused from proxy %s", node->nodestr);
return -EINVAL;
}
px_ctx->px_state = PROXY_STATE_HTTP_TUNNEL_ESTABLISHED;
if (proxy_ctx_node_next(px_ctx) == NULL) {
forward_event(nsp, nse, udata);
} else {
px_ctx->px_current = proxy_ctx_node_next(px_ctx);
px_ctx->px_state = PROXY_STATE_INITIAL;
nsock_proxy_ev_dispatch(nsp, nse, udata);
}
return 0;
}
static void proxy_http_handler(nsock_pool nspool, nsock_event nsevent, void *udata) {
int rc = 0;
struct npool *nsp = (struct npool *)nspool;
struct nevent *nse = (struct nevent *)nsevent;
switch (nse->iod->px_ctx->px_state) {
case PROXY_STATE_INITIAL:
rc = handle_state_initial(nsp, nse, udata);
break;
case PROXY_STATE_HTTP_TCP_CONNECTED:
if (nse->type == NSE_TYPE_READ)
rc = handle_state_tcp_connected(nsp, nse, udata);
break;
case PROXY_STATE_HTTP_TUNNEL_ESTABLISHED:
forward_event(nsp, nse, udata);
break;
default:
fatal("Invalid proxy state!");
}
if (rc) {
nse->status = NSE_STATUS_PROXYERROR;
forward_event(nsp, nse, udata);
}
}
/* ---- PROXY DEFINITION ---- */
static const struct proxy_op ProxyOpsHttp = {
proxy_http_node_new,
proxy_http_node_delete,
proxy_http_handler,
};
const struct proxy_spec ProxySpecHttp = {
"http://",
PROXY_TYPE_HTTP,
&ProxyOpsHttp,
};
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