| /* |
| * 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" |
| RCSID("$OpenBSD: compress.c,v 1.20 2004/01/13 19:23:15 markus Exp $"); |
| |
| #include "log.h" |
| #include "buffer.h" |
| #include "zlib.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", |
| outgoing_stream.total_in, 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", |
| incoming_stream.total_out, 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 */ |
| } |
| } |
| } |