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-rw-r--r--src/openvpn/comp-lz4.c307
1 files changed, 307 insertions, 0 deletions
diff --git a/src/openvpn/comp-lz4.c b/src/openvpn/comp-lz4.c
new file mode 100644
index 0000000..395f3d2
--- /dev/null
+++ b/src/openvpn/comp-lz4.c
@@ -0,0 +1,307 @@
+/*
+ * 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) 2002-2012 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ * Copyright (C) 2013 Gert Doering <gert@greenie.muc.de>
+ *
+ * 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
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#if defined(ENABLE_LZ4)
+
+#if defined(NEED_COMPAT_LZ4)
+#include "compat-lz4.h"
+#else
+#include "lz4.h"
+#endif
+
+#include "comp.h"
+#include "error.h"
+
+#include "memdbg.h"
+
+static void
+lz4_compress_init (struct compress_context *compctx)
+{
+ msg (D_INIT_MEDIUM, "LZ4 compression initializing");
+ ASSERT(compctx->flags & COMP_F_SWAP);
+}
+
+static void
+lz4v2_compress_init (struct compress_context *compctx)
+{
+ msg (D_INIT_MEDIUM, "LZ4v2 compression initializing");
+}
+
+static void
+lz4_compress_uninit (struct compress_context *compctx)
+{
+}
+
+static bool
+do_lz4_compress (struct buffer *buf,
+ struct buffer *work,
+ struct compress_context *compctx,
+ const struct frame* frame)
+{
+ /*
+ * In order to attempt compression, length must be at least COMPRESS_THRESHOLD.
+ */
+ if (buf->len >= COMPRESS_THRESHOLD)
+ {
+ const size_t ps = PAYLOAD_SIZE (frame);
+ int zlen_max = ps + COMP_EXTRA_BUFFER (ps);
+ int zlen;
+
+ ASSERT (buf_init (work, FRAME_HEADROOM (frame)));
+ ASSERT (buf_safe (work, zlen_max));
+
+ if (buf->len > ps)
+ {
+ dmsg (D_COMP_ERRORS, "LZ4 compression buffer overflow");
+ buf->len = 0;
+ return false;
+ }
+
+ zlen = LZ4_compress_limitedOutput((const char *)BPTR(buf), (char *)BPTR(work), BLEN(buf), zlen_max );
+
+ if (zlen <= 0)
+ {
+ dmsg (D_COMP_ERRORS, "LZ4 compression error");
+ buf->len = 0;
+ return false;
+ }
+
+ ASSERT (buf_safe (work, zlen));
+ work->len = zlen;
+
+
+ dmsg (D_COMP, "LZ4 compress %d -> %d", buf->len, work->len);
+ compctx->pre_compress += buf->len;
+ compctx->post_compress += work->len;
+ return true;
+ }
+ return false;
+}
+
+
+static void
+lz4_compress (struct buffer *buf, struct buffer work,
+ struct compress_context *compctx,
+ const struct frame* frame)
+{
+ bool compressed;
+ if (buf->len <= 0)
+ return;
+
+ compressed = do_lz4_compress(buf, &work, compctx, frame);
+
+ /* On error do_lz4_compress sets buf len to zero, just return */
+ if (buf->len == 0)
+ return;
+
+ /* did compression save us anything? */
+ {
+ uint8_t comp_head_byte = NO_COMPRESS_BYTE_SWAP;
+ if (compressed && work.len < buf->len)
+ {
+ *buf = work;
+ comp_head_byte = LZ4_COMPRESS_BYTE;
+ }
+
+ {
+ uint8_t *head = BPTR (buf);
+ uint8_t *tail = BEND (buf);
+ ASSERT (buf_safe (buf, 1));
+ ++buf->len;
+
+ /* move head byte of payload to tail */
+ *tail = *head;
+ *head = comp_head_byte;
+ }
+ }
+}
+
+
+static void
+lz4v2_compress (struct buffer *buf, struct buffer work,
+ struct compress_context *compctx,
+ const struct frame* frame)
+{
+ bool compressed;
+ if (buf->len <= 0)
+ return;
+
+ compressed = do_lz4_compress(buf, &work, compctx, frame);
+
+ /* On Error just return */
+ if (buf->len == 0)
+ return;
+
+ /* did compression save us anything? Include 2 byte compression header
+ in calculation */
+ if (compressed && work.len + 2 < buf->len)
+ {
+ ASSERT(buf_prepend(&work, 2));
+ uint8_t *head = BPTR (&work);
+ head[0] = COMP_ALGV2_INDICATOR_BYTE;
+ head[1] = COMP_ALGV2_LZ4_BYTE;
+ *buf = work;
+ }
+ else
+ {
+ compv2_escape_data_ifneeded(buf);
+ }
+}
+
+void
+do_lz4_decompress(size_t zlen_max,
+ struct buffer *work,
+ struct buffer *buf,
+ struct compress_context *compctx)
+{
+ int uncomp_len;
+ ASSERT (buf_safe (work, zlen_max));
+ uncomp_len = LZ4_decompress_safe((const char *)BPTR(buf), (char *)BPTR(work), (size_t)BLEN(buf), zlen_max);
+ if (uncomp_len <= 0)
+ {
+ dmsg (D_COMP_ERRORS, "LZ4 decompression error: %d", uncomp_len);
+ buf->len = 0;
+ return;
+ }
+
+ ASSERT (buf_safe (work, uncomp_len));
+ work->len = uncomp_len;
+
+ dmsg (D_COMP, "LZ4 decompress %d -> %d", buf->len, work->len);
+ compctx->pre_decompress += buf->len;
+ compctx->post_decompress += work->len;
+
+ *buf = *work;
+}
+
+static void
+lz4_decompress (struct buffer *buf, struct buffer work,
+ struct compress_context *compctx,
+ const struct frame* frame)
+{
+ size_t zlen_max = EXPANDED_SIZE (frame);
+ uint8_t c; /* flag indicating whether or not our peer compressed */
+
+ if (buf->len <= 0)
+ return;
+
+ ASSERT (buf_init (&work, FRAME_HEADROOM (frame)));
+
+ /* do unframing/swap (assumes buf->len > 0) */
+ {
+ uint8_t *head = BPTR (buf);
+ c = *head;
+ --buf->len;
+ *head = *BEND (buf);
+ }
+
+ if (c == LZ4_COMPRESS_BYTE) /* packet was compressed */
+ {
+ do_lz4_decompress(zlen_max, &work, buf, compctx);
+ }
+ else if (c == NO_COMPRESS_BYTE_SWAP) /* packet was not compressed */
+ {
+ ;
+ }
+ else
+ {
+ dmsg (D_COMP_ERRORS, "Bad LZ4 decompression header byte: %d", c);
+ buf->len = 0;
+ }
+}
+
+static void
+lz4v2_decompress (struct buffer *buf, struct buffer work,
+ struct compress_context *compctx,
+ const struct frame* frame)
+{
+ size_t zlen_max = EXPANDED_SIZE (frame);
+ uint8_t c; /* flag indicating whether or not our peer compressed */
+
+ if (buf->len <= 0)
+ return;
+
+ ASSERT (buf_init (&work, FRAME_HEADROOM (frame)));
+
+ /* do unframing/swap (assumes buf->len > 0) */
+ uint8_t *head = BPTR (buf);
+ c = *head;
+
+ /* Not compressed */
+ if (c != COMP_ALGV2_INDICATOR_BYTE) {
+ return;
+ }
+
+ /* Packet to short to make sense */
+ if (buf->len <= 1)
+ {
+ buf->len=0;
+ return;
+ }
+
+ c = head[1];
+ if (c == COMP_ALGV2_LZ4_BYTE) /* packet was compressed */
+ {
+ buf_advance(buf,2);
+ do_lz4_decompress(zlen_max, &work, buf, compctx);
+ }
+ else if (c == COMP_ALGV2_UNCOMPRESSED_BYTE)
+ {
+ buf_advance(buf,2);
+ }
+ else
+ {
+ dmsg (D_COMP_ERRORS, "Bad LZ4v2 decompression header byte: %d", c);
+ buf->len = 0;
+ }
+}
+
+const struct compress_alg lz4_alg = {
+ "lz4",
+ lz4_compress_init,
+ lz4_compress_uninit,
+ lz4_compress,
+ lz4_decompress
+};
+
+const struct compress_alg lz4v2_alg = {
+ "lz4v2",
+ lz4v2_compress_init,
+ lz4_compress_uninit,
+ lz4v2_compress,
+ lz4v2_decompress
+};
+
+#else
+static void dummy(void) {}
+#endif /* ENABLE_LZ4 */
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