badvpn/socksclient/BSocksClient.h

/**
 * @file BSocksClient.h
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * This file is part of BadVPN.
 * 
 * BadVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 * 
 * BadVPN 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * @section DESCRIPTION
 * 
 * SOCKS5 client. TCP only, no authentication.
 */

#ifndef BADVPN_SOCKS_BSOCKSCLIENT_H
#define BADVPN_SOCKS_BSOCKSCLIENT_H

#include <stdint.h>

#include <misc/debug.h>
#include <misc/debugerror.h>
#include <misc/socks_proto.h>
#include <base/DebugObject.h>
#include <system/BSocket.h>
#include <flow/PacketStreamSender.h>
#include <flowextra/StreamSocketSink.h>
#include <flowextra/StreamSocketSource.h>

#define BSOCKSCLIENT_EVENT_ERROR 1
#define BSOCKSCLIENT_EVENT_UP 2
#define BSOCKSCLIENT_EVENT_ERROR_CLOSED 3

/**
 * Handler for events generated by the SOCKS client.
 * 
 * @param user as in {@link BSocksClient_Init}
 * @param event event type. One of BSOCKSCLIENT_EVENT_ERROR, BSOCKSCLIENT_EVENT_UP
 *              and BSOCKSCLIENT_EVENT_ERROR_CLOSED.
 *              If event is BSOCKSCLIENT_EVENT_UP, the object was previously in down
 *              state and has transitioned to up state; I/O can be done from this point on.
 *              If event is BSOCKSCLIENT_EVENT_ERROR or BSOCKSCLIENT_EVENT_ERROR_CLOSED,
 *              the object must be freed from within the job closure of this handler,
 *              and no further I/O must be attempted.
 */
typedef void (*BSocksClient_handler) (void *user, int event);

typedef struct {
    BAddr dest_addr;
    BSocksClient_handler handler;
    void *user;
    BReactor *reactor;
    int state;
    FlowErrorDomain domain;
    BSocket sock;
    union {
        struct {
            PacketPassInterface *send_if;
            PacketStreamSender send_sender;
            StreamSocketSink send_sink;
            StreamSocketSource recv_source;
            StreamRecvInterface *recv_if;
            union {
                struct {
                    struct socks_client_hello_header header;
                    struct socks_client_hello_method method;
                } __attribute__((packed)) client_hello;
                struct socks_server_hello server_hello;
                struct {
                    struct socks_request_header header;
                    union {
                        struct socks_addr_ipv4 ipv4;
                        struct socks_addr_ipv6 ipv6;
                    } addr;
                } __attribute__((packed)) request;
                struct {
                    struct socks_reply_header header;
                    union {
                        struct socks_addr_ipv4 ipv4;
                        struct socks_addr_ipv6 ipv6;
                    } addr;
                } __attribute__((packed)) reply;
            } msg;
            uint8_t *recv_dest;
            int recv_len;
            int recv_total;
        } control;
        struct {
            StreamSocketSink send_sink;
            StreamSocketSource recv_source;
        } up;
    };
    DebugError d_err;
    DebugObject d_obj;
} BSocksClient;

/**
 * Initializes the object.
 * The object is initialized in down state. The object must transition to up
 * state before the user may begin any I/O.
 * 
 * @param o the object
 * @param server_addr SOCKS5 server address
 * @param dest_addr remote address
 * @param handler handler for up and error events
 * @param user value passed to handler
 * @param reactor reactor we live in
 * @return 1 on success, 0 on failure
 */
int BSocksClient_Init (BSocksClient *o, BAddr server_addr, BAddr dest_addr, BSocksClient_handler handler, void *user, BReactor *reactor) WARN_UNUSED;

/**
 * Frees the object.
 * 
 * @param o the object
 */
void BSocksClient_Free (BSocksClient *o);

/**
 * Returns the send interface.
 * The object must be in up state.
 * 
 * @param o the object
 * @return send interface
 */
StreamPassInterface * BSocksClient_GetSendInterface (BSocksClient *o);

/**
 * Returns the receive interface.
 * The object must be in up state.
 * 
 * @param o the object
 * @return receive interface
 */
StreamRecvInterface * BSocksClient_GetRecvInterface (BSocksClient *o);

#endif