diff options
Diffstat (limited to 'crypto/openssh/compress.c')
| -rw-r--r-- | crypto/openssh/compress.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/crypto/openssh/compress.c b/crypto/openssh/compress.c new file mode 100644 index 0000000..c058d22 --- /dev/null +++ b/crypto/openssh/compress.c @@ -0,0 +1,166 @@ +/* $OpenBSD: compress.c,v 1.25 2006/08/06 01:13:32 stevesk Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * Interface to packet compression for ssh. + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + */ + +#include "includes.h" + +#include <sys/types.h> + +#include <stdarg.h> +#include <zlib.h> + +#include "log.h" +#include "buffer.h" +#include "compress.h" + +z_stream incoming_stream; +z_stream outgoing_stream; +static int compress_init_send_called = 0; +static int compress_init_recv_called = 0; +static int inflate_failed = 0; +static int deflate_failed = 0; + +/* + * Initializes compression; level is compression level from 1 to 9 + * (as in gzip). + */ + +void +buffer_compress_init_send(int level) +{ + if (compress_init_send_called == 1) + deflateEnd(&outgoing_stream); + compress_init_send_called = 1; + debug("Enabling compression at level %d.", level); + if (level < 1 || level > 9) + fatal("Bad compression level %d.", level); + deflateInit(&outgoing_stream, level); +} +void +buffer_compress_init_recv(void) +{ + if (compress_init_recv_called == 1) + inflateEnd(&incoming_stream); + compress_init_recv_called = 1; + inflateInit(&incoming_stream); +} + +/* Frees any data structures allocated for compression. */ + +void +buffer_compress_uninit(void) +{ + debug("compress outgoing: raw data %llu, compressed %llu, factor %.2f", + (unsigned long long)outgoing_stream.total_in, + (unsigned long long)outgoing_stream.total_out, + outgoing_stream.total_in == 0 ? 0.0 : + (double) outgoing_stream.total_out / outgoing_stream.total_in); + debug("compress incoming: raw data %llu, compressed %llu, factor %.2f", + (unsigned long long)incoming_stream.total_out, + (unsigned long long)incoming_stream.total_in, + incoming_stream.total_out == 0 ? 0.0 : + (double) incoming_stream.total_in / incoming_stream.total_out); + if (compress_init_recv_called == 1 && inflate_failed == 0) + inflateEnd(&incoming_stream); + if (compress_init_send_called == 1 && deflate_failed == 0) + deflateEnd(&outgoing_stream); +} + +/* + * Compresses the contents of input_buffer into output_buffer. All packets + * compressed using this function will form a single compressed data stream; + * however, data will be flushed at the end of every call so that each + * output_buffer can be decompressed independently (but in the appropriate + * order since they together form a single compression stream) by the + * receiver. This appends the compressed data to the output buffer. + */ + +void +buffer_compress(Buffer * input_buffer, Buffer * output_buffer) +{ + u_char buf[4096]; + int status; + + /* This case is not handled below. */ + if (buffer_len(input_buffer) == 0) + return; + + /* Input is the contents of the input buffer. */ + outgoing_stream.next_in = buffer_ptr(input_buffer); + outgoing_stream.avail_in = buffer_len(input_buffer); + + /* Loop compressing until deflate() returns with avail_out != 0. */ + do { + /* Set up fixed-size output buffer. */ + outgoing_stream.next_out = buf; + outgoing_stream.avail_out = sizeof(buf); + + /* Compress as much data into the buffer as possible. */ + status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH); + switch (status) { + case Z_OK: + /* Append compressed data to output_buffer. */ + buffer_append(output_buffer, buf, + sizeof(buf) - outgoing_stream.avail_out); + break; + default: + deflate_failed = 1; + fatal("buffer_compress: deflate returned %d", status); + /* NOTREACHED */ + } + } while (outgoing_stream.avail_out == 0); +} + +/* + * Uncompresses the contents of input_buffer into output_buffer. All packets + * uncompressed using this function will form a single compressed data + * stream; however, data will be flushed at the end of every call so that + * each output_buffer. This must be called for the same size units that the + * buffer_compress was called, and in the same order that buffers compressed + * with that. This appends the uncompressed data to the output buffer. + */ + +void +buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) +{ + u_char buf[4096]; + int status; + + incoming_stream.next_in = buffer_ptr(input_buffer); + incoming_stream.avail_in = buffer_len(input_buffer); + + for (;;) { + /* Set up fixed-size output buffer. */ + incoming_stream.next_out = buf; + incoming_stream.avail_out = sizeof(buf); + + status = inflate(&incoming_stream, Z_PARTIAL_FLUSH); + switch (status) { + case Z_OK: + buffer_append(output_buffer, buf, + sizeof(buf) - incoming_stream.avail_out); + break; + case Z_BUF_ERROR: + /* + * Comments in zlib.h say that we should keep calling + * inflate() until we get an error. This appears to + * be the error that we get. + */ + return; + default: + inflate_failed = 1; + fatal("buffer_uncompress: inflate returned %d", status); + /* NOTREACHED */ + } + } +} |
