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/***************************************************************************
* nsock_proxy.h -- PRIVATE interface definitions for proxy handling. *
* *
***********************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).
*
***************************************************************************/
/* $Id$ */
#ifndef NSOCK_PROXY_H
#define NSOCK_PROXY_H
#include "gh_list.h"
#if HAVE_NETDB_H
#include <netdb.h>
#endif
#include <nsock.h>
#include <errno.h>
/* ------------------- CONSTANTS ------------------- */
enum nsock_proxy_type {
PROXY_TYPE_HTTP = 0,
PROXY_TYPE_SOCKS4,
PROXY_TYPE_COUNT,
};
enum nsock_proxy_state {
/* Common initial state for all proxy types. */
PROXY_STATE_INITIAL,
/* HTTP proxy states. */
PROXY_STATE_HTTP_TCP_CONNECTED,
PROXY_STATE_HTTP_TUNNEL_ESTABLISHED,
/* SOCKS 4 proxy states. */
PROXY_STATE_SOCKS4_TCP_CONNECTED,
PROXY_STATE_SOCKS4_TUNNEL_ESTABLISHED,
};
/* ------------------- STRUCTURES ------------------- */
struct uri {
char *scheme;
char *user;
char *pass;
char *host;
char *path;
int port;
};
/* Static information about a proxy node in the chain. This is generated by
* parsing the proxy specification string given by user. Those structures are
* then read-only and stored in the nsock_pool. */
struct proxy_node {
const struct proxy_spec *spec;
struct sockaddr_storage ss;
size_t sslen;
unsigned short port;
char *nodestr; /* used for log messages */
gh_lnode_t nodeq;
};
/* Ordered list of proxy nodes, as specified in the proxy specification string. */
struct proxy_chain {
gh_list_t nodes;
};
/* IOD-specific context. For each IOD we establish a tunnel through the chain of
* proxies. This structure stores all the related information. */
struct proxy_chain_context {
const struct proxy_chain *px_chain;
/* Nodes iterator in px_chain->nodes */
struct proxy_node *px_current;
/* Current node connection state. */
enum nsock_proxy_state px_state;
/* Those fields are used to store information about the final target
* to reach. */
enum nse_type target_ev_type;
struct sockaddr_storage target_ss;
size_t target_sslen;
unsigned short target_port;
nsock_ev_handler target_handler;
};
struct proxy_op {
int (*node_new)(struct proxy_node **node, const struct uri *uri);
void (*node_delete)(struct proxy_node *node);
void (*handler)(nsock_pool nspool, nsock_event nsevent, void *udata);
};
struct proxy_spec {
const char *prefix;
enum nsock_proxy_type type;
const struct proxy_op *ops;
};
/* ------------------- UTIL FUNCTIONS ------------------- */
int proxy_resolve(const char *host, struct sockaddr *addr, size_t *addrlen, int ai_family);
static inline struct proxy_node *proxy_ctx_node_next(struct proxy_chain_context *ctx) {
gh_lnode_t *next;
assert(ctx);
assert(ctx->px_current);
next = gh_lnode_next(&ctx->px_current->nodeq);
if (!next)
return NULL;
return container_of(next, struct proxy_node, nodeq);
}
/* ------------------- PROTOTYPES ------------------- */
struct proxy_chain_context *proxy_chain_context_new(nsock_pool nspool);
void proxy_chain_context_delete(struct proxy_chain_context *ctx);
void nsock_proxy_ev_dispatch(nsock_pool nspool, nsock_event nsevent, void *udata);
void forward_event(nsock_pool nspool, nsock_event nse, void *udata);
#endif /* NSOCK_PROXY_H */
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