mirror of
https://github.com/OpenVPN/openvpn.git
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564a21094e
git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@5599 e7ae566f-a301-0410-adde-c780ea21d3b5
189 lines
6.0 KiB
C
189 lines
6.0 KiB
C
/*
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* OpenVPN -- An application to securely tunnel IP networks
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* over a single UDP port, with support for SSL/TLS-based
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* session authentication and key exchange,
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* packet encryption, packet authentication, and
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* packet compression.
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*
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* Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (see the file COPYING included with this
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* distribution); if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef FRAGMENT_H
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#define FRAGMENT_H
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#ifdef ENABLE_FRAGMENT
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#include "common.h"
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#include "buffer.h"
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#include "interval.h"
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#include "mtu.h"
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#include "shaper.h"
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#include "error.h"
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#define N_FRAG_BUF 25 /* number of packet buffers */
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#define FRAG_TTL_SEC 10 /* number of seconds time-to-live for a fragment */
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#define FRAG_WAKEUP_INTERVAL 5 /* wakeup code called once per n seconds */
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struct fragment {
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bool defined;
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int max_frag_size; /* maximum size of each fragment */
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/*
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* 32 bit array corresponding to each fragment. A 1 bit in element n means that
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* the fragment n has been received. Needs to have at least MAX_FRAGS bits.
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*/
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# define FRAG_MAP_MASK 0xFFFFFFFF
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# define MAX_FRAGS 32 /* maximum number of fragments per packet */
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unsigned int map;
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time_t timestamp; /* timestamp for time-to-live purposes */
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struct buffer buf; /* fragment assembly buffer for received datagrams */
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};
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struct fragment_list {
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int seq_id;
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int index;
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struct fragment fragments[N_FRAG_BUF];
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};
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struct fragment_master {
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struct event_timeout wakeup; /* when should main openvpn event loop wake us up */
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/* true if the OS has explicitly recommended an MTU value */
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bool received_os_mtu_hint;
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/* a sequence ID describes a set of fragments that make up one datagram */
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# define N_SEQ_ID 256 /* sequence number wraps to 0 at this value (should be a power of 2) */
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int outgoing_seq_id; /* sent as FRAG_SEQ_ID below */
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/* outgoing packet is possibly sent as a series of fragments */
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# define MAX_FRAG_PKT_SIZE 65536 /* maximum packet size */
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int outgoing_frag_size; /* sent to peer via FRAG_SIZE when FRAG_YES_LAST set */
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int outgoing_frag_id; /* each fragment in a datagram is numbered 0 to MAX_FRAGS-1 */
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struct buffer outgoing; /* outgoing datagram, free if current_frag_id == 0 */
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struct buffer outgoing_return; /* buffer to return outgoing fragment */
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/* incoming fragments from remote */
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struct fragment_list incoming;
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};
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/*
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* Fragment header sent over the wire.
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*/
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typedef uint32_t fragment_header_type;
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/* convert a fragment_header_type from host to network order */
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#define hton_fragment_header_type(x) htonl(x)
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/* convert a fragment_header_type from network to host order */
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#define ntoh_fragment_header_type(x) ntohl(x)
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/* FRAG_TYPE 2 bits */
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#define FRAG_TYPE_MASK 0x00000003
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#define FRAG_TYPE_SHIFT 0
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#define FRAG_WHOLE 0 /* packet is whole, FRAG_N_PACKETS_RECEIVED echoed back to peer */
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#define FRAG_YES_NOTLAST 1 /* packet is a fragment, but is not the last fragment,
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FRAG_N_PACKETS_RECEIVED set as above */
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#define FRAG_YES_LAST 2 /* packet is the last fragment, FRAG_SIZE = size of non-last frags */
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#define FRAG_TEST 3 /* control packet for establishing MTU size (not implemented yet) */
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/* FRAG_SEQ_ID 8 bits */
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#define FRAG_SEQ_ID_MASK 0x000000ff
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#define FRAG_SEQ_ID_SHIFT 2
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/* FRAG_ID 5 bits */
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#define FRAG_ID_MASK 0x0000001f
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#define FRAG_ID_SHIFT 10
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/*
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* FRAG_SIZE 14 bits
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*
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* IF FRAG_YES_LAST (FRAG_SIZE):
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* The max size of a fragment. If a fragment is not the last fragment in the packet,
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* then the fragment size is guaranteed to be equal to the max fragment size. Therefore,
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* max_frag_size is only sent over the wire if FRAG_LAST is set. Otherwise it is assumed
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* to be the actual fragment size received.
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*/
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/* FRAG_SIZE 14 bits */
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#define FRAG_SIZE_MASK 0x00003fff
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#define FRAG_SIZE_SHIFT 15
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#define FRAG_SIZE_ROUND_SHIFT 2 /* fragment/datagram sizes represented as multiple of 4 */
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#define FRAG_SIZE_ROUND_MASK ((1 << FRAG_SIZE_ROUND_SHIFT) - 1)
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/*
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* FRAG_EXTRA 16 bits
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*
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* IF FRAG_WHOLE or FRAG_YES_NOTLAST, these 16 bits are available (not currently used)
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*/
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/* FRAG_EXTRA 16 bits */
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#define FRAG_EXTRA_MASK 0x0000ffff
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#define FRAG_EXTRA_SHIFT 15
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/*
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* Public functions
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*/
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struct fragment_master *fragment_init (struct frame *frame);
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void fragment_frame_init (struct fragment_master *f, const struct frame *frame);
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void fragment_free (struct fragment_master *f);
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void fragment_incoming (struct fragment_master *f, struct buffer *buf,
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const struct frame* frame);
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void fragment_outgoing (struct fragment_master *f, struct buffer *buf,
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const struct frame* frame);
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bool fragment_ready_to_send (struct fragment_master *f, struct buffer *buf,
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const struct frame* frame);
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/*
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* Private functions.
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*/
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void fragment_wakeup (struct fragment_master *f, struct frame *frame);
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/*
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* Inline functions
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*/
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static inline void
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fragment_housekeeping (struct fragment_master *f, struct frame *frame, struct timeval *tv)
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{
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if (event_timeout_trigger (&f->wakeup, tv, ETT_DEFAULT))
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fragment_wakeup (f, frame);
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}
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static inline bool
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fragment_outgoing_defined (struct fragment_master *f)
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{
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return f->outgoing.len > 0;
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}
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#endif
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#endif
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