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Diffstat (limited to 'openvpn/src/openvpn/lzo.c')
-rw-r--r--openvpn/src/openvpn/lzo.c310
1 files changed, 310 insertions, 0 deletions
diff --git a/openvpn/src/openvpn/lzo.c b/openvpn/src/openvpn/lzo.c
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+++ b/openvpn/src/openvpn/lzo.c
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+/*
+ * 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
+ */
+
+/**
+ * @file Data Channel Compression module function definitions.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#ifdef ENABLE_LZO
+
+#include "lzo.h"
+#include "error.h"
+#include "otime.h"
+
+#include "memdbg.h"
+
+#ifndef ENABLE_LZO_STUB
+/**
+ * Perform adaptive compression housekeeping.
+ *
+ * @param ac the adaptive compression state structure.
+ *
+ * @return
+ */
+static bool
+lzo_adaptive_compress_test (struct lzo_adaptive_compress *ac)
+{
+ const bool save = ac->compress_state;
+ const time_t local_now = now;
+
+ if (!ac->compress_state)
+ {
+ if (local_now >= ac->next)
+ {
+ if (ac->n_total > AC_MIN_BYTES
+ && (ac->n_total - ac->n_comp) < (ac->n_total / (100 / AC_SAVE_PCT)))
+ {
+ ac->compress_state = true;
+ ac->next = local_now + AC_OFF_SEC;
+ }
+ else
+ {
+ ac->next = local_now + AC_SAMP_SEC;
+ }
+ dmsg (D_COMP, "lzo_adaptive_compress_test: comp=%d total=%d", ac->n_comp, ac->n_total);
+ ac->n_total = ac->n_comp = 0;
+ }
+ }
+ else
+ {
+ if (local_now >= ac->next)
+ {
+ ac->next = local_now + AC_SAMP_SEC;
+ ac->n_total = ac->n_comp = 0;
+ ac->compress_state = false;
+ }
+ }
+
+ if (ac->compress_state != save)
+ dmsg (D_COMP_LOW, "Adaptive compression state %s", (ac->compress_state ? "OFF" : "ON"));
+
+ return !ac->compress_state;
+}
+
+static inline void
+lzo_adaptive_compress_data (struct lzo_adaptive_compress *ac, int n_total, int n_comp)
+{
+ ac->n_total += n_total;
+ ac->n_comp += n_comp;
+}
+
+#endif /* ENABLE_LZO_STUB */
+
+void lzo_adjust_frame_parameters (struct frame *frame)
+{
+ /* Leave room for our one-byte compressed/didn't-compress prefix byte. */
+ frame_add_to_extra_frame (frame, LZO_PREFIX_LEN);
+
+ /* Leave room for compression buffer to expand in worst case scenario
+ where data is totally uncompressible */
+ frame_add_to_extra_buffer (frame, LZO_EXTRA_BUFFER (EXPANDED_SIZE(frame)));
+}
+
+void
+lzo_compress_init (struct lzo_compress_workspace *lzowork, unsigned int flags)
+{
+ CLEAR (*lzowork);
+
+ lzowork->flags = flags;
+#ifndef ENABLE_LZO_STUB
+ lzowork->wmem_size = LZO_WORKSPACE;
+
+ if (lzo_init () != LZO_E_OK)
+ msg (M_FATAL, "Cannot initialize LZO compression library");
+ lzowork->wmem = (lzo_voidp) lzo_malloc (lzowork->wmem_size);
+ check_malloc_return (lzowork->wmem);
+ msg (D_INIT_MEDIUM, "LZO compression initialized");
+#else
+ msg (D_INIT_MEDIUM, "LZO stub compression initialized");
+#endif
+ lzowork->defined = true;
+}
+
+void
+lzo_compress_uninit (struct lzo_compress_workspace *lzowork)
+{
+ if (lzowork)
+ {
+ ASSERT (lzowork->defined);
+#ifndef ENABLE_LZO_STUB
+ lzo_free (lzowork->wmem);
+ lzowork->wmem = NULL;
+#endif
+ lzowork->defined = false;
+ }
+}
+
+static inline bool
+lzo_compression_enabled (struct lzo_compress_workspace *lzowork)
+{
+#ifndef ENABLE_LZO_STUB
+ if ((lzowork->flags & (LZO_SELECTED|LZO_ON)) == (LZO_SELECTED|LZO_ON))
+ {
+ if (lzowork->flags & LZO_ADAPTIVE)
+ return lzo_adaptive_compress_test (&lzowork->ac);
+ else
+ return true;
+ }
+#endif
+ return false;
+}
+
+void
+lzo_compress (struct buffer *buf, struct buffer work,
+ struct lzo_compress_workspace *lzowork,
+ const struct frame* frame)
+{
+#ifndef ENABLE_LZO_STUB
+ lzo_uint zlen = 0;
+ int err;
+ bool compressed = false;
+#endif
+
+ ASSERT (lzowork->defined);
+
+ if (buf->len <= 0)
+ return;
+
+#ifndef ENABLE_LZO_STUB
+ /*
+ * In order to attempt compression, length must be at least COMPRESS_THRESHOLD,
+ * and our adaptive level must give the OK.
+ */
+ if (buf->len >= COMPRESS_THRESHOLD && lzo_compression_enabled (lzowork))
+ {
+ ASSERT (buf_init (&work, FRAME_HEADROOM (frame)));
+ ASSERT (buf_safe (&work, LZO_EXTRA_BUFFER (PAYLOAD_SIZE (frame))));
+
+ if (!(buf->len <= PAYLOAD_SIZE (frame)))
+ {
+ dmsg (D_COMP_ERRORS, "LZO compression buffer overflow");
+ buf->len = 0;
+ return;
+ }
+
+ err = LZO_COMPRESS (BPTR (buf), BLEN (buf), BPTR (&work), &zlen, lzowork->wmem);
+ if (err != LZO_E_OK)
+ {
+ dmsg (D_COMP_ERRORS, "LZO compression error: %d", err);
+ buf->len = 0;
+ return;
+ }
+
+ ASSERT (buf_safe (&work, zlen));
+ work.len = zlen;
+ compressed = true;
+
+ dmsg (D_COMP, "compress %d -> %d", buf->len, work.len);
+ lzowork->pre_compress += buf->len;
+ lzowork->post_compress += work.len;
+
+ /* tell adaptive level about our success or lack thereof in getting any size reduction */
+ if (lzowork->flags & LZO_ADAPTIVE)
+ lzo_adaptive_compress_data (&lzowork->ac, buf->len, work.len);
+ }
+
+ /* did compression save us anything ? */
+ if (compressed && work.len < buf->len)
+ {
+ uint8_t *header = buf_prepend (&work, 1);
+ *header = YES_COMPRESS;
+ *buf = work;
+ }
+ else
+#endif
+ {
+ uint8_t *header = buf_prepend (buf, 1);
+ *header = NO_COMPRESS;
+ }
+}
+
+void
+lzo_decompress (struct buffer *buf, struct buffer work,
+ struct lzo_compress_workspace *lzowork,
+ const struct frame* frame)
+{
+#ifndef ENABLE_LZO_STUB
+ lzo_uint zlen = EXPANDED_SIZE (frame);
+ int err;
+#endif
+ uint8_t c; /* flag indicating whether or not our peer compressed */
+
+ ASSERT (lzowork->defined);
+
+ if (buf->len <= 0)
+ return;
+
+ ASSERT (buf_init (&work, FRAME_HEADROOM (frame)));
+
+ c = *BPTR (buf);
+ ASSERT (buf_advance (buf, 1));
+
+ if (c == YES_COMPRESS) /* packet was compressed */
+ {
+#ifndef ENABLE_LZO_STUB
+ ASSERT (buf_safe (&work, zlen));
+ err = LZO_DECOMPRESS (BPTR (buf), BLEN (buf), BPTR (&work), &zlen,
+ lzowork->wmem);
+ if (err != LZO_E_OK)
+ {
+ dmsg (D_COMP_ERRORS, "LZO decompression error: %d", err);
+ buf->len = 0;
+ return;
+ }
+
+ ASSERT (buf_safe (&work, zlen));
+ work.len = zlen;
+
+ dmsg (D_COMP, "decompress %d -> %d", buf->len, work.len);
+ lzowork->pre_decompress += buf->len;
+ lzowork->post_decompress += work.len;
+
+ *buf = work;
+#else
+ dmsg (D_COMP_ERRORS, "LZO decompression error: LZO capability not compiled");
+ buf->len = 0;
+ return;
+#endif
+ }
+ else if (c == NO_COMPRESS) /* packet was not compressed */
+ {
+ ;
+ }
+ else
+ {
+ dmsg (D_COMP_ERRORS, "Bad LZO decompression header byte: %d", c);
+ buf->len = 0;
+ }
+}
+
+void
+lzo_modify_flags (struct lzo_compress_workspace *lzowork, unsigned int flags)
+{
+ ASSERT (lzowork->defined);
+ lzowork->flags = flags;
+}
+
+void lzo_print_stats (const struct lzo_compress_workspace *lzo_compwork, struct status_output *so)
+{
+ ASSERT (lzo_compwork->defined);
+
+#ifndef ENABLE_LZO_STUB
+ status_printf (so, "pre-compress bytes," counter_format, lzo_compwork->pre_compress);
+ status_printf (so, "post-compress bytes," counter_format, lzo_compwork->post_compress);
+ status_printf (so, "pre-decompress bytes," counter_format, lzo_compwork->pre_decompress);
+ status_printf (so, "post-decompress bytes," counter_format, lzo_compwork->post_decompress);
+#endif
+}
+
+#else
+static void dummy(void) {}
+#endif /* ENABLE_LZO */
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