1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * Author: Tatu Ylonen <ylo@cs.hut.fi> 3*0Sstevel@tonic-gate * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4*0Sstevel@tonic-gate * All rights reserved 5*0Sstevel@tonic-gate * Interface to packet compression for ssh. 6*0Sstevel@tonic-gate * 7*0Sstevel@tonic-gate * As far as I am concerned, the code I have written for this software 8*0Sstevel@tonic-gate * can be used freely for any purpose. Any derived versions of this 9*0Sstevel@tonic-gate * software must be clearly marked as such, and if the derived work is 10*0Sstevel@tonic-gate * incompatible with the protocol description in the RFC file, it must be 11*0Sstevel@tonic-gate * called by a name other than "ssh" or "Secure Shell". 12*0Sstevel@tonic-gate */ 13*0Sstevel@tonic-gate 14*0Sstevel@tonic-gate #include "includes.h" 15*0Sstevel@tonic-gate RCSID("$OpenBSD: compress.c,v 1.19 2002/03/18 17:31:54 provos Exp $"); 16*0Sstevel@tonic-gate 17*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 18*0Sstevel@tonic-gate 19*0Sstevel@tonic-gate #include "log.h" 20*0Sstevel@tonic-gate #include "buffer.h" 21*0Sstevel@tonic-gate #include "zlib.h" 22*0Sstevel@tonic-gate #include "compress.h" 23*0Sstevel@tonic-gate 24*0Sstevel@tonic-gate z_stream incoming_stream; 25*0Sstevel@tonic-gate z_stream outgoing_stream; 26*0Sstevel@tonic-gate static int compress_init_send_called = 0; 27*0Sstevel@tonic-gate static int compress_init_recv_called = 0; 28*0Sstevel@tonic-gate static int inflate_failed = 0; 29*0Sstevel@tonic-gate static int deflate_failed = 0; 30*0Sstevel@tonic-gate 31*0Sstevel@tonic-gate /* 32*0Sstevel@tonic-gate * Initializes compression; level is compression level from 1 to 9 33*0Sstevel@tonic-gate * (as in gzip). 34*0Sstevel@tonic-gate */ 35*0Sstevel@tonic-gate 36*0Sstevel@tonic-gate void 37*0Sstevel@tonic-gate buffer_compress_init_send(int level) 38*0Sstevel@tonic-gate { 39*0Sstevel@tonic-gate if (compress_init_send_called == 1) 40*0Sstevel@tonic-gate deflateEnd(&outgoing_stream); 41*0Sstevel@tonic-gate compress_init_send_called = 1; 42*0Sstevel@tonic-gate debug("Enabling compression at level %d.", level); 43*0Sstevel@tonic-gate if (level < 1 || level > 9) 44*0Sstevel@tonic-gate fatal("Bad compression level %d.", level); 45*0Sstevel@tonic-gate deflateInit(&outgoing_stream, level); 46*0Sstevel@tonic-gate } 47*0Sstevel@tonic-gate void 48*0Sstevel@tonic-gate buffer_compress_init_recv(void) 49*0Sstevel@tonic-gate { 50*0Sstevel@tonic-gate if (compress_init_recv_called == 1) 51*0Sstevel@tonic-gate inflateEnd(&incoming_stream); 52*0Sstevel@tonic-gate compress_init_recv_called = 1; 53*0Sstevel@tonic-gate inflateInit(&incoming_stream); 54*0Sstevel@tonic-gate } 55*0Sstevel@tonic-gate 56*0Sstevel@tonic-gate /* Frees any data structures allocated for compression. */ 57*0Sstevel@tonic-gate 58*0Sstevel@tonic-gate void 59*0Sstevel@tonic-gate buffer_compress_uninit(void) 60*0Sstevel@tonic-gate { 61*0Sstevel@tonic-gate debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f", 62*0Sstevel@tonic-gate outgoing_stream.total_in, outgoing_stream.total_out, 63*0Sstevel@tonic-gate outgoing_stream.total_in == 0 ? 0.0 : 64*0Sstevel@tonic-gate (double) outgoing_stream.total_out / outgoing_stream.total_in); 65*0Sstevel@tonic-gate debug("compress incoming: raw data %lu, compressed %lu, factor %.2f", 66*0Sstevel@tonic-gate incoming_stream.total_out, incoming_stream.total_in, 67*0Sstevel@tonic-gate incoming_stream.total_out == 0 ? 0.0 : 68*0Sstevel@tonic-gate (double) incoming_stream.total_in / incoming_stream.total_out); 69*0Sstevel@tonic-gate if (compress_init_recv_called == 1 && inflate_failed == 0) 70*0Sstevel@tonic-gate inflateEnd(&incoming_stream); 71*0Sstevel@tonic-gate if (compress_init_send_called == 1 && deflate_failed == 0) 72*0Sstevel@tonic-gate deflateEnd(&outgoing_stream); 73*0Sstevel@tonic-gate } 74*0Sstevel@tonic-gate 75*0Sstevel@tonic-gate /* 76*0Sstevel@tonic-gate * Compresses the contents of input_buffer into output_buffer. All packets 77*0Sstevel@tonic-gate * compressed using this function will form a single compressed data stream; 78*0Sstevel@tonic-gate * however, data will be flushed at the end of every call so that each 79*0Sstevel@tonic-gate * output_buffer can be decompressed independently (but in the appropriate 80*0Sstevel@tonic-gate * order since they together form a single compression stream) by the 81*0Sstevel@tonic-gate * receiver. This appends the compressed data to the output buffer. 82*0Sstevel@tonic-gate */ 83*0Sstevel@tonic-gate 84*0Sstevel@tonic-gate void 85*0Sstevel@tonic-gate buffer_compress(Buffer * input_buffer, Buffer * output_buffer) 86*0Sstevel@tonic-gate { 87*0Sstevel@tonic-gate u_char buf[4096]; 88*0Sstevel@tonic-gate int status; 89*0Sstevel@tonic-gate 90*0Sstevel@tonic-gate /* This case is not handled below. */ 91*0Sstevel@tonic-gate if (buffer_len(input_buffer) == 0) 92*0Sstevel@tonic-gate return; 93*0Sstevel@tonic-gate 94*0Sstevel@tonic-gate /* Input is the contents of the input buffer. */ 95*0Sstevel@tonic-gate outgoing_stream.next_in = buffer_ptr(input_buffer); 96*0Sstevel@tonic-gate outgoing_stream.avail_in = buffer_len(input_buffer); 97*0Sstevel@tonic-gate 98*0Sstevel@tonic-gate /* Loop compressing until deflate() returns with avail_out != 0. */ 99*0Sstevel@tonic-gate do { 100*0Sstevel@tonic-gate /* Set up fixed-size output buffer. */ 101*0Sstevel@tonic-gate outgoing_stream.next_out = buf; 102*0Sstevel@tonic-gate outgoing_stream.avail_out = sizeof(buf); 103*0Sstevel@tonic-gate 104*0Sstevel@tonic-gate /* Compress as much data into the buffer as possible. */ 105*0Sstevel@tonic-gate status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH); 106*0Sstevel@tonic-gate switch (status) { 107*0Sstevel@tonic-gate case Z_OK: 108*0Sstevel@tonic-gate /* Append compressed data to output_buffer. */ 109*0Sstevel@tonic-gate buffer_append(output_buffer, buf, 110*0Sstevel@tonic-gate sizeof(buf) - outgoing_stream.avail_out); 111*0Sstevel@tonic-gate break; 112*0Sstevel@tonic-gate default: 113*0Sstevel@tonic-gate deflate_failed = 1; 114*0Sstevel@tonic-gate fatal("buffer_compress: deflate returned %d", status); 115*0Sstevel@tonic-gate /* NOTREACHED */ 116*0Sstevel@tonic-gate } 117*0Sstevel@tonic-gate } while (outgoing_stream.avail_out == 0); 118*0Sstevel@tonic-gate } 119*0Sstevel@tonic-gate 120*0Sstevel@tonic-gate /* 121*0Sstevel@tonic-gate * Uncompresses the contents of input_buffer into output_buffer. All packets 122*0Sstevel@tonic-gate * uncompressed using this function will form a single compressed data 123*0Sstevel@tonic-gate * stream; however, data will be flushed at the end of every call so that 124*0Sstevel@tonic-gate * each output_buffer. This must be called for the same size units that the 125*0Sstevel@tonic-gate * buffer_compress was called, and in the same order that buffers compressed 126*0Sstevel@tonic-gate * with that. This appends the uncompressed data to the output buffer. 127*0Sstevel@tonic-gate */ 128*0Sstevel@tonic-gate 129*0Sstevel@tonic-gate void 130*0Sstevel@tonic-gate buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer) 131*0Sstevel@tonic-gate { 132*0Sstevel@tonic-gate u_char buf[4096]; 133*0Sstevel@tonic-gate int status; 134*0Sstevel@tonic-gate 135*0Sstevel@tonic-gate incoming_stream.next_in = buffer_ptr(input_buffer); 136*0Sstevel@tonic-gate incoming_stream.avail_in = buffer_len(input_buffer); 137*0Sstevel@tonic-gate 138*0Sstevel@tonic-gate for (;;) { 139*0Sstevel@tonic-gate /* Set up fixed-size output buffer. */ 140*0Sstevel@tonic-gate incoming_stream.next_out = buf; 141*0Sstevel@tonic-gate incoming_stream.avail_out = sizeof(buf); 142*0Sstevel@tonic-gate 143*0Sstevel@tonic-gate status = inflate(&incoming_stream, Z_PARTIAL_FLUSH); 144*0Sstevel@tonic-gate switch (status) { 145*0Sstevel@tonic-gate case Z_OK: 146*0Sstevel@tonic-gate buffer_append(output_buffer, buf, 147*0Sstevel@tonic-gate sizeof(buf) - incoming_stream.avail_out); 148*0Sstevel@tonic-gate break; 149*0Sstevel@tonic-gate case Z_BUF_ERROR: 150*0Sstevel@tonic-gate /* 151*0Sstevel@tonic-gate * Comments in zlib.h say that we should keep calling 152*0Sstevel@tonic-gate * inflate() until we get an error. This appears to 153*0Sstevel@tonic-gate * be the error that we get. 154*0Sstevel@tonic-gate */ 155*0Sstevel@tonic-gate return; 156*0Sstevel@tonic-gate default: 157*0Sstevel@tonic-gate inflate_failed = 1; 158*0Sstevel@tonic-gate fatal("buffer_uncompress: inflate returned %d", status); 159*0Sstevel@tonic-gate /* NOTREACHED */ 160*0Sstevel@tonic-gate } 161*0Sstevel@tonic-gate } 162*0Sstevel@tonic-gate } 163