/* * ==FILEVERSION 980319== * * ppp_deflate.c - interface the zlib procedures for Deflate compression * and decompression (as used by gzip) to the PPP code. * This version is for use with Linux kernel 1.3.X. * * Copyright (c) 1994 The Australian National University. * All rights reserved. * * Permission to use, copy, modify, and distribute this software and its * documentation is hereby granted, provided that the above copyright * notice appears in all copies. This software is provided without any * warranty, express or implied. The Australian National University * makes no representations about the suitability of this software for * any purpose. * * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, * OR MODIFICATIONS. * * From: deflate.c,v 1.1 1996/01/18 03:17:48 paulus Exp */ #include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/init.h> #include <linux/string.h> #include <linux/ppp_defs.h> #include <linux/ppp-comp.h> #include <linux/zlib.h> /* * State for a Deflate (de)compressor. */ struct ppp_deflate_state { int seqno; int w_size; int unit; int mru; int debug; z_stream strm; struct compstat stats; }; #define DEFLATE_OVHD 2 /* Deflate overhead/packet */ static void *z_comp_alloc(unsigned char *options, int opt_len); static void *z_decomp_alloc(unsigned char *options, int opt_len); static void z_comp_free(void *state); static void z_decomp_free(void *state); static int z_comp_init(void *state, unsigned char *options, int opt_len, int unit, int hdrlen, int debug); static int z_decomp_init(void *state, unsigned char *options, int opt_len, int unit, int hdrlen, int mru, int debug); static int z_compress(void *state, unsigned char *rptr, unsigned char *obuf, int isize, int osize); static void z_incomp(void *state, unsigned char *ibuf, int icnt); static int z_decompress(void *state, unsigned char *ibuf, int isize, unsigned char *obuf, int osize); static void z_comp_reset(void *state); static void z_decomp_reset(void *state); static void z_comp_stats(void *state, struct compstat *stats); /** * z_comp_free - free the memory used by a compressor * @arg: pointer to the private state for the compressor. */ static void z_comp_free(void *arg) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; if (state) { zlib_deflateEnd(&state->strm); vfree(state->strm.workspace); kfree(state); } } /** * z_comp_alloc - allocate space for a compressor. * @options: pointer to CCP option data * @opt_len: length of the CCP option at @options. * * The @options pointer points to the a buffer containing the * CCP option data for the compression being negotiated. It is * formatted according to RFC1979, and describes the window * size that the peer is requesting that we use in compressing * data to be sent to it. * * Returns the pointer to the private state for the compressor, * or NULL if we could not allocate enough memory. */ static void *z_comp_alloc(unsigned char *options, int opt_len) { struct ppp_deflate_state *state; int w_size; if (opt_len != CILEN_DEFLATE || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || options[3] != DEFLATE_CHK_SEQUENCE) return NULL; w_size = DEFLATE_SIZE(options[2]); if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) return NULL; state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL); if (state == NULL) return NULL; memset (state, 0, sizeof (struct ppp_deflate_state)); state->strm.next_in = NULL; state->w_size = w_size; state->strm.workspace = vmalloc(zlib_deflate_workspacesize()); if (state->strm.workspace == NULL) goto out_free; if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) goto out_free; return (void *) state; out_free: z_comp_free(state); return NULL; } /** * z_comp_init - initialize a previously-allocated compressor. * @arg: pointer to the private state for the compressor * @options: pointer to the CCP option data describing the * compression that was negotiated with the peer * @opt_len: length of the CCP option data at @options * @unit: PPP unit number for diagnostic messages * @hdrlen: ignored (present for backwards compatibility) * @debug: debug flag; if non-zero, debug messages are printed. * * The CCP options described by @options must match the options * specified when the compressor was allocated. The compressor * history is reset. Returns 0 for failure (CCP options don't * match) or 1 for success. */ static int z_comp_init(void *arg, unsigned char *options, int opt_len, int unit, int hdrlen, int debug) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; if (opt_len < CILEN_DEFLATE || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || DEFLATE_SIZE(options[2]) != state->w_size || options[3] != DEFLATE_CHK_SEQUENCE) return 0; state->seqno = 0; state->unit = unit; state->debug = debug; zlib_deflateReset(&state->strm); return 1; } /** * z_comp_reset - reset a previously-allocated compressor. * @arg: pointer to private state for the compressor. * * This clears the history for the compressor and makes it * ready to start emitting a new compressed stream. */ static void z_comp_reset(void *arg) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; state->seqno = 0; zlib_deflateReset(&state->strm); } /** * z_compress - compress a PPP packet with Deflate compression. * @arg: pointer to private state for the compressor * @rptr: uncompressed packet (input) * @obuf: compressed packet (output) * @isize: size of uncompressed packet * @osize: space available at @obuf * * Returns the length of the compressed packet, or 0 if the * packet is incompressible. */ int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf, int isize, int osize) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; int r, proto, off, olen, oavail; unsigned char *wptr; /* * Check that the protocol is in the range we handle. */ proto = PPP_PROTOCOL(rptr); if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) return 0; /* Don't generate compressed packets which are larger than the uncompressed packet. */ if (osize > isize) osize = isize; wptr = obuf; /* * Copy over the PPP header and store the 2-byte sequence number. */ wptr[0] = PPP_ADDRESS(rptr); wptr[1] = PPP_CONTROL(rptr); wptr[2] = PPP_COMP >> 8; wptr[3] = PPP_COMP; wptr += PPP_HDRLEN; wptr[0] = state->seqno >> 8; wptr[1] = state->seqno; wptr += DEFLATE_OVHD; olen = PPP_HDRLEN + DEFLATE_OVHD; state->strm.next_out = wptr; state->strm.avail_out = oavail = osize - olen; ++state->seqno; off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */ rptr += off; state->strm.next_in = rptr; state->strm.avail_in = (isize - off); for (;;) { r = zlib_deflate(&state->strm, Z_PACKET_FLUSH); if (r != Z_OK) { if (state->debug) printk(KERN_ERR "z_compress: deflate returned %d\n", r); break; } if (state->strm.avail_out == 0) { olen += oavail; state->strm.next_out = NULL; state->strm.avail_out = oavail = 1000000; } else { break; /* all done */ } } olen += oavail - state->strm.avail_out; /* * See if we managed to reduce the size of the packet. */ if (olen < isize) { state->stats.comp_bytes += olen; state->stats.comp_packets++; } else { state->stats.inc_bytes += isize; state->stats.inc_packets++; olen = 0; } state->stats.unc_bytes += isize; state->stats.unc_packets++; return olen; } /** * z_comp_stats - return compression statistics for a compressor * or decompressor. * @arg: pointer to private space for the (de)compressor * @stats: pointer to a struct compstat to receive the result. */ static void z_comp_stats(void *arg, struct compstat *stats) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; *stats = state->stats; } /** * z_decomp_free - Free the memory used by a decompressor. * @arg: pointer to private space for the decompressor. */ static void z_decomp_free(void *arg) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; if (state) { zlib_inflateEnd(&state->strm); kfree(state->strm.workspace); kfree(state); } } /** * z_decomp_alloc - allocate space for a decompressor. * @options: pointer to CCP option data * @opt_len: length of the CCP option at @options. * * The @options pointer points to the a buffer containing the * CCP option data for the compression being negotiated. It is * formatted according to RFC1979, and describes the window * size that we are requesting the peer to use in compressing * data to be sent to us. * * Returns the pointer to the private state for the decompressor, * or NULL if we could not allocate enough memory. */ static void *z_decomp_alloc(unsigned char *options, int opt_len) { struct ppp_deflate_state *state; int w_size; if (opt_len != CILEN_DEFLATE || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || options[3] != DEFLATE_CHK_SEQUENCE) return NULL; w_size = DEFLATE_SIZE(options[2]); if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) return NULL; state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL); if (state == NULL) return NULL; memset (state, 0, sizeof (struct ppp_deflate_state)); state->w_size = w_size; state->strm.next_out = NULL; state->strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL|__GFP_REPEAT); if (state->strm.workspace == NULL) goto out_free; if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK) goto out_free; return (void *) state; out_free: z_decomp_free(state); return NULL; } /** * z_decomp_init - initialize a previously-allocated decompressor. * @arg: pointer to the private state for the decompressor * @options: pointer to the CCP option data describing the * compression that was negotiated with the peer * @opt_len: length of the CCP option data at @options * @unit: PPP unit number for diagnostic messages * @hdrlen: ignored (present for backwards compatibility) * @mru: maximum length of decompressed packets * @debug: debug flag; if non-zero, debug messages are printed. * * The CCP options described by @options must match the options * specified when the decompressor was allocated. The decompressor * history is reset. Returns 0 for failure (CCP options don't * match) or 1 for success. */ static int z_decomp_init(void *arg, unsigned char *options, int opt_len, int unit, int hdrlen, int mru, int debug) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; if (opt_len < CILEN_DEFLATE || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || DEFLATE_SIZE(options[2]) != state->w_size || options[3] != DEFLATE_CHK_SEQUENCE) return 0; state->seqno = 0; state->unit = unit; state->debug = debug; state->mru = mru; zlib_inflateReset(&state->strm); return 1; } /** * z_decomp_reset - reset a previously-allocated decompressor. * @arg: pointer to private state for the decompressor. * * This clears the history for the decompressor and makes it * ready to receive a new compressed stream. */ static void z_decomp_reset(void *arg) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; state->seqno = 0; zlib_inflateReset(&state->strm); } /** * z_decompress - decompress a Deflate-compressed packet. * @arg: pointer to private state for the decompressor * @ibuf: pointer to input (compressed) packet data * @isize: length of input packet * @obuf: pointer to space for output (decompressed) packet * @osize: amount of space available at @obuf * * Because of patent problems, we return DECOMP_ERROR for errors * found by inspecting the input data and for system problems, but * DECOMP_FATALERROR for any errors which could possibly be said to * be being detected "after" decompression. For DECOMP_ERROR, * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be * infringing a patent of Motorola's if we do, so we take CCP down * instead. * * Given that the frame has the correct sequence number and a good FCS, * errors such as invalid codes in the input most likely indicate a * bug, so we return DECOMP_FATALERROR for them in order to turn off * compression, even though they are detected by inspecting the input. */ int z_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, int osize) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; int olen, seq, r; int decode_proto, overflow; unsigned char overflow_buf[1]; if (isize <= PPP_HDRLEN + DEFLATE_OVHD) { if (state->debug) printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n", state->unit, isize); return DECOMP_ERROR; } /* Check the sequence number. */ seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1]; if (seq != (state->seqno & 0xffff)) { if (state->debug) printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n", state->unit, seq, state->seqno & 0xffff); return DECOMP_ERROR; } ++state->seqno; /* * Fill in the first part of the PPP header. The protocol field * comes from the decompressed data. */ obuf[0] = PPP_ADDRESS(ibuf); obuf[1] = PPP_CONTROL(ibuf); obuf[2] = 0; /* * Set up to call inflate. We set avail_out to 1 initially so we can * look at the first byte of the output and decide whether we have * a 1-byte or 2-byte protocol field. */ state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD; state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD); state->strm.next_out = obuf + 3; state->strm.avail_out = 1; decode_proto = 1; overflow = 0; /* * Call inflate, supplying more input or output as needed. */ for (;;) { r = zlib_inflate(&state->strm, Z_PACKET_FLUSH); if (r != Z_OK) { if (state->debug) printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n", state->unit, r, (state->strm.msg? state->strm.msg: "")); return DECOMP_FATALERROR; } if (state->strm.avail_out != 0) break; /* all done */ if (decode_proto) { state->strm.avail_out = osize - PPP_HDRLEN; if ((obuf[3] & 1) == 0) { /* 2-byte protocol field */ obuf[2] = obuf[3]; --state->strm.next_out; ++state->strm.avail_out; } decode_proto = 0; } else if (!overflow) { /* * We've filled up the output buffer; the only way to * find out whether inflate has any more characters * left is to give it another byte of output space. */ state->strm.next_out = overflow_buf; state->strm.avail_out = 1; overflow = 1; } else { if (state->debug) printk(KERN_DEBUG "z_decompress%d: ran out of mru\n", state->unit); return DECOMP_FATALERROR; } } if (decode_proto) { if (state->debug) printk(KERN_DEBUG "z_decompress%d: didn't get proto\n", state->unit); return DECOMP_ERROR; } olen = osize + overflow - state->strm.avail_out; state->stats.unc_bytes += olen; state->stats.unc_packets++; state->stats.comp_bytes += isize; state->stats.comp_packets++; return olen; } /** * z_incomp - add incompressible input data to the history. * @arg: pointer to private state for the decompressor * @ibuf: pointer to input packet data * @icnt: length of input data. */ static void z_incomp(void *arg, unsigned char *ibuf, int icnt) { struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg; int proto, r; /* * Check that the protocol is one we handle. */ proto = PPP_PROTOCOL(ibuf); if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) return; ++state->seqno; /* * We start at the either the 1st or 2nd byte of the protocol field, * depending on whether the protocol value is compressible. */ state->strm.next_in = ibuf + 3; state->strm.avail_in = icnt - 3; if (proto > 0xff) { --state->strm.next_in; ++state->strm.avail_in; } r = zlib_inflateIncomp(&state->strm); if (r != Z_OK) { /* gak! */ if (state->debug) { printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n", state->unit, r, (state->strm.msg? state->strm.msg: "")); } return; } /* * Update stats. */ state->stats.inc_bytes += icnt; state->stats.inc_packets++; state->stats.unc_bytes += icnt; state->stats.unc_packets++; } /************************************************************* * Module interface table *************************************************************/ /* These are in ppp_generic.c */ extern int ppp_register_compressor (struct compressor *cp); extern void ppp_unregister_compressor (struct compressor *cp); /* * Procedures exported to if_ppp.c. */ static struct compressor ppp_deflate = { .compress_proto = CI_DEFLATE, .comp_alloc = z_comp_alloc, .comp_free = z_comp_free, .comp_init = z_comp_init, .comp_reset = z_comp_reset, .compress = z_compress, .comp_stat = z_comp_stats, .decomp_alloc = z_decomp_alloc, .decomp_free = z_decomp_free, .decomp_init = z_decomp_init, .decomp_reset = z_decomp_reset, .decompress = z_decompress, .incomp = z_incomp, .decomp_stat = z_comp_stats, .owner = THIS_MODULE }; static struct compressor ppp_deflate_draft = { .compress_proto = CI_DEFLATE_DRAFT, .comp_alloc = z_comp_alloc, .comp_free = z_comp_free, .comp_init = z_comp_init, .comp_reset = z_comp_reset, .compress = z_compress, .comp_stat = z_comp_stats, .decomp_alloc = z_decomp_alloc, .decomp_free = z_decomp_free, .decomp_init = z_decomp_init, .decomp_reset = z_decomp_reset, .decompress = z_decompress, .incomp = z_incomp, .decomp_stat = z_comp_stats, .owner = THIS_MODULE }; static int __init deflate_init(void) { int answer = ppp_register_compressor(&ppp_deflate); if (answer == 0) printk(KERN_INFO "PPP Deflate Compression module registered\n"); ppp_register_compressor(&ppp_deflate_draft); return answer; } static void __exit deflate_cleanup(void) { ppp_unregister_compressor(&ppp_deflate); ppp_unregister_compressor(&ppp_deflate_draft); } module_init(deflate_init); module_exit(deflate_cleanup); MODULE_LICENSE("Dual BSD/GPL"); MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE)); MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));