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-rw-r--r--fragment.c408
1 files changed, 0 insertions, 408 deletions
diff --git a/fragment.c b/fragment.c
deleted file mode 100644
index 5ef3a47..0000000
--- a/fragment.c
+++ /dev/null
@@ -1,408 +0,0 @@
-/*
- * OpenVPN -- An application to securely tunnel IP networks
- * over a single UDP port, with support for SSL/TLS-based
- * session authentication and key exchange,
- * packet encryption, packet authentication, and
- * packet compression.
- *
- * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
- *
- * This program 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.
- *
- * 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 for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program (see the file COPYING included with this
- * distribution); if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#include "syshead.h"
-
-#ifdef ENABLE_FRAGMENT
-
-#include "misc.h"
-#include "fragment.h"
-#include "integer.h"
-#include "memdbg.h"
-
-#define FRAG_ERR(s) { errmsg = s; goto error; }
-
-static void
-fragment_list_buf_init (struct fragment_list *list, const struct frame *frame)
-{
- int i;
- for (i = 0; i < N_FRAG_BUF; ++i)
- list->fragments[i].buf = alloc_buf (BUF_SIZE (frame));
-}
-
-static void
-fragment_list_buf_free (struct fragment_list *list)
-{
- int i;
- for (i = 0; i < N_FRAG_BUF; ++i)
- free_buf (&list->fragments[i].buf);
-}
-
-/*
- * Given a sequence ID number, get a fragment buffer. Use a sliding window,
- * similar to packet_id code.
- */
-static struct fragment *
-fragment_list_get_buf (struct fragment_list *list, int seq_id)
-{
- int diff;
- if (abs (diff = modulo_subtract (seq_id, list->seq_id, N_SEQ_ID)) >= N_FRAG_BUF)
- {
- int i;
- for (i = 0; i < N_FRAG_BUF; ++i)
- list->fragments[i].defined = false;
- list->index = 0;
- list->seq_id = seq_id;
- diff = 0;
- }
- while (diff > 0)
- {
- list->fragments[list->index = modulo_add (list->index, 1, N_FRAG_BUF)].defined = false;
- list->seq_id = modulo_add (list->seq_id, 1, N_SEQ_ID);
- --diff;
- }
- return &list->fragments[modulo_add (list->index, diff, N_FRAG_BUF)];
-}
-
-struct fragment_master *
-fragment_init (struct frame *frame)
-{
- struct fragment_master *ret;
-
- /* code that initializes other parts of
- fragment_master assume an initial CLEAR */
- ALLOC_OBJ_CLEAR (ret, struct fragment_master);
-
- /* add in the size of our contribution to the expanded frame size */
- frame_add_to_extra_frame (frame, sizeof(fragment_header_type));
-
- /*
- * Outgoing sequence ID is randomized to reduce
- * the probability of sequence number collisions
- * when openvpn sessions are restarted. This is
- * not done out of any need for security, as all
- * fragmentation control information resides
- * inside of the encrypted/authenticated envelope.
- */
- ret->outgoing_seq_id = (int)get_random() & (N_SEQ_ID - 1);
-
- event_timeout_init (&ret->wakeup, FRAG_WAKEUP_INTERVAL, now);
-
- return ret;
-}
-
-void
-fragment_free (struct fragment_master *f)
-{
- fragment_list_buf_free (&f->incoming);
- free_buf (&f->outgoing);
- free_buf (&f->outgoing_return);
- free (f);
-}
-
-void
-fragment_frame_init (struct fragment_master *f, const struct frame *frame)
-{
- fragment_list_buf_init (&f->incoming, frame);
- f->outgoing = alloc_buf (BUF_SIZE (frame));
- f->outgoing_return = alloc_buf (BUF_SIZE (frame));
-}
-
-/*
- * Accept an incoming datagram (which may be a fragment) from remote.
- * If the datagram is whole (i.e not a fragment), pass through.
- * If the datagram is a fragment, join with other fragments received so far.
- * If a fragment fully completes the datagram, return the datagram.
- */
-void
-fragment_incoming (struct fragment_master *f, struct buffer *buf,
- const struct frame* frame)
-{
- const char *errmsg = NULL;
- fragment_header_type flags = 0;
- int frag_type = 0;
-
- if (buf->len > 0)
- {
- /* get flags from packet head */
- if (!buf_read (buf, &flags, sizeof (flags)))
- FRAG_ERR ("flags not found in packet");
- flags = ntoh_fragment_header_type (flags);
-
- /* get fragment type from flags */
- frag_type = ((flags >> FRAG_TYPE_SHIFT) & FRAG_TYPE_MASK);
-
-#if 0
- /*
- * If you want to extract FRAG_EXTRA_MASK/FRAG_EXTRA_SHIFT bits,
- * do it here.
- */
- if (frag_type == FRAG_WHOLE || frag_type == FRAG_YES_NOTLAST)
- {
- }
-#endif
-
- /* handle the fragment type */
- if (frag_type == FRAG_WHOLE)
- {
- dmsg (D_FRAG_DEBUG,
- "FRAG_IN buf->len=%d type=FRAG_WHOLE flags="
- fragment_header_format,
- buf->len,
- flags);
-
- if (flags & (FRAG_SEQ_ID_MASK | FRAG_ID_MASK))
- FRAG_ERR ("spurrious FRAG_WHOLE flags");
- }
- else if (frag_type == FRAG_YES_NOTLAST || frag_type == FRAG_YES_LAST)
- {
- const int seq_id = ((flags >> FRAG_SEQ_ID_SHIFT) & FRAG_SEQ_ID_MASK);
- const int n = ((flags >> FRAG_ID_SHIFT) & FRAG_ID_MASK);
- const int size = ((frag_type == FRAG_YES_LAST)
- ? (int)(((flags >> FRAG_SIZE_SHIFT) & FRAG_SIZE_MASK) << FRAG_SIZE_ROUND_SHIFT)
- : buf->len);
-
- /* get the appropriate fragment buffer based on received seq_id */
- struct fragment *frag = fragment_list_get_buf (&f->incoming, seq_id);
-
- dmsg (D_FRAG_DEBUG,
- "FRAG_IN len=%d type=%d seq_id=%d frag_id=%d size=%d flags="
- fragment_header_format,
- buf->len,
- frag_type,
- seq_id,
- n,
- size,
- flags);
-
- /* make sure that size is an even multiple of 1<<FRAG_SIZE_ROUND_SHIFT */
- if (size & FRAG_SIZE_ROUND_MASK)
- FRAG_ERR ("bad fragment size");
-
- /* is this the first fragment for our sequence number? */
- if (!frag->defined || (frag->defined && frag->max_frag_size != size))
- {
- frag->defined = true;
- frag->max_frag_size = size;
- frag->map = 0;
- ASSERT (buf_init (&frag->buf, FRAME_HEADROOM_ADJ (frame, FRAME_HEADROOM_MARKER_FRAGMENT)));
- }
-
- /* copy the data to fragment buffer */
- if (!buf_copy_range (&frag->buf, n * size, buf, 0, buf->len))
- FRAG_ERR ("fragment buffer overflow");
-
- /* set elements in bit array to reflect which fragments have been received */
- frag->map |= (((frag_type == FRAG_YES_LAST) ? FRAG_MAP_MASK : 1) << n);
-
- /* update timestamp on partially built datagram */
- frag->timestamp = now;
-
- /* received full datagram? */
- if ((frag->map & FRAG_MAP_MASK) == FRAG_MAP_MASK)
- {
- frag->defined = false;
- *buf = frag->buf;
- }
- else
- {
- buf->len = 0;
- }
- }
- else if (frag_type == FRAG_TEST)
- {
- FRAG_ERR ("FRAG_TEST not implemented");
- }
- else
- {
- FRAG_ERR ("unknown fragment type");
- }
- }
-
- return;
-
- error:
- if (errmsg)
- msg (D_FRAG_ERRORS, "FRAG_IN error flags=" fragment_header_format ": %s", flags, errmsg);
- buf->len = 0;
- return;
-}
-
-/* pack fragment parms into a uint32_t and prepend to buffer */
-static void
-fragment_prepend_flags (struct buffer *buf,
- int type,
- int seq_id,
- int frag_id,
- int frag_size)
-{
- fragment_header_type flags = ((type & FRAG_TYPE_MASK) << FRAG_TYPE_SHIFT)
- | ((seq_id & FRAG_SEQ_ID_MASK) << FRAG_SEQ_ID_SHIFT)
- | ((frag_id & FRAG_ID_MASK) << FRAG_ID_SHIFT);
-
- if (type == FRAG_WHOLE || type == FRAG_YES_NOTLAST)
- {
- /*
- * If you want to set FRAG_EXTRA_MASK/FRAG_EXTRA_SHIFT bits,
- * do it here.
- */
- dmsg (D_FRAG_DEBUG,
- "FRAG_OUT len=%d type=%d seq_id=%d frag_id=%d frag_size=%d flags="
- fragment_header_format,
- buf->len, type, seq_id, frag_id, frag_size, flags);
- }
- else
- {
- flags |= (((frag_size >> FRAG_SIZE_ROUND_SHIFT) & FRAG_SIZE_MASK) << FRAG_SIZE_SHIFT);
-
- dmsg (D_FRAG_DEBUG,
- "FRAG_OUT len=%d type=%d seq_id=%d frag_id=%d frag_size=%d flags="
- fragment_header_format,
- buf->len, type, seq_id, frag_id, frag_size, flags);
- }
-
- flags = hton_fragment_header_type (flags);
- ASSERT (buf_write_prepend (buf, &flags, sizeof (flags)));
-}
-
-/*
- * Without changing the number of fragments, return a possibly smaller
- * max fragment size that will allow for the last fragment to be of
- * similar size as previous fragments.
- */
-static inline int
-optimal_fragment_size (int len, int max_frag_size)
-{
- const int mfs_aligned = (max_frag_size & ~FRAG_SIZE_ROUND_MASK);
- const int div = len / mfs_aligned;
- const int mod = len % mfs_aligned;
-
- if (div > 0 && mod > 0 && mod < mfs_aligned * 3 / 4)
- return min_int (mfs_aligned, (max_frag_size - ((max_frag_size - mod) / (div + 1))
- + FRAG_SIZE_ROUND_MASK) & ~FRAG_SIZE_ROUND_MASK);
- else
- return mfs_aligned;
-}
-
-/* process an outgoing datagram, possibly breaking it up into fragments */
-void
-fragment_outgoing (struct fragment_master *f, struct buffer *buf,
- const struct frame* frame)
-{
- const char *errmsg = NULL;
- if (buf->len > 0)
- {
- /* The outgoing buffer should be empty so we can put new data in it */
- if (f->outgoing.len)
- msg (D_FRAG_ERRORS, "FRAG: outgoing buffer is not empty, len=[%d,%d]",
- buf->len, f->outgoing.len);
- if (buf->len > PAYLOAD_SIZE_DYNAMIC(frame)) /* should we fragment? */
- {
- /*
- * Send the datagram as a series of 2 or more fragments.
- */
- f->outgoing_frag_size = optimal_fragment_size (buf->len, PAYLOAD_SIZE_DYNAMIC(frame));
- if (buf->len > f->outgoing_frag_size * MAX_FRAGS)
- FRAG_ERR ("too many fragments would be required to send datagram");
- ASSERT (buf_init (&f->outgoing, FRAME_HEADROOM (frame)));
- ASSERT (buf_copy (&f->outgoing, buf));
- f->outgoing_seq_id = modulo_add (f->outgoing_seq_id, 1, N_SEQ_ID);
- f->outgoing_frag_id = 0;
- buf->len = 0;
- ASSERT (fragment_ready_to_send (f, buf, frame));
- }
- else
- {
- /*
- * Send the datagram whole.
- */
- fragment_prepend_flags (buf,
- FRAG_WHOLE,
- 0,
- 0,
- 0);
- }
- }
- return;
-
- error:
- if (errmsg)
- msg (D_FRAG_ERRORS, "FRAG_OUT error, len=%d frag_size=%d MAX_FRAGS=%d: %s",
- buf->len, f->outgoing_frag_size, MAX_FRAGS, errmsg);
- buf->len = 0;
- return;
-}
-
-/* return true (and set buf) if we have an outgoing fragment which is ready to send */
-bool
-fragment_ready_to_send (struct fragment_master *f, struct buffer *buf,
- const struct frame* frame)
-{
- if (fragment_outgoing_defined (f))
- {
- /* get fragment size, and determine if it is the last fragment */
- int size = f->outgoing_frag_size;
- int last = false;
- if (f->outgoing.len <= size)
- {
- size = f->outgoing.len;
- last = true;
- }
-
- /* initialize return buffer */
- *buf = f->outgoing_return;
- ASSERT (buf_init (buf, FRAME_HEADROOM (frame)));
- ASSERT (buf_copy_n (buf, &f->outgoing, size));
-
- /* fragment flags differ based on whether or not we are sending the last fragment */
- fragment_prepend_flags (buf,
- last ? FRAG_YES_LAST : FRAG_YES_NOTLAST,
- f->outgoing_seq_id,
- f->outgoing_frag_id++,
- f->outgoing_frag_size);
-
- ASSERT (!last || !f->outgoing.len); /* outgoing buffer length should be zero after last fragment sent */
-
- return true;
- }
- else
- return false;
-}
-
-static void
-fragment_ttl_reap (struct fragment_master *f)
-{
- int i;
- for (i = 0; i < N_FRAG_BUF; ++i)
- {
- struct fragment *frag = &f->incoming.fragments[i];
- if (frag->defined && frag->timestamp + FRAG_TTL_SEC <= now)
- {
- msg (D_FRAG_ERRORS, "FRAG TTL expired i=%d", i);
- frag->defined = false;
- }
- }
-}
-
-/* called every FRAG_WAKEUP_INTERVAL seconds */
-void
-fragment_wakeup (struct fragment_master *f, struct frame *frame)
-{
- /* delete fragments with expired TTLs */
- fragment_ttl_reap (f);
-}
-
-#else
-static void dummy(void) {}
-#endif