alistair23-linux/drivers/net/ppp_deflate.c
Jim Keniston 565d76cb7d zlib: slim down zlib_deflate() workspace when possible
Instead of always creating a huge (268K) deflate_workspace with the
maximum compression parameters (windowBits=15, memLevel=8), allow the
caller to obtain a smaller workspace by specifying smaller parameter
values.

For example, when capturing oops and panic reports to a medium with
limited capacity, such as NVRAM, compression may be the only way to
capture the whole report.  In this case, a small workspace (24K works
fine) is a win, whether you allocate the workspace when you need it (i.e.,
during an oops or panic) or at boot time.

I've verified that this patch works with all accepted values of windowBits
(positive and negative), memLevel, and compression level.

Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:17 -07:00

655 lines
19 KiB
C

/*
* ==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>
#include <asm/unaligned.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 = kzalloc(sizeof(*state),
GFP_KERNEL);
if (state == NULL)
return NULL;
state->strm.next_in = NULL;
state->w_size = w_size;
state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
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.
*/
static 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);
put_unaligned_be16(PPP_COMP, wptr + 2);
wptr += PPP_HDRLEN;
put_unaligned_be16(state->seqno, wptr);
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 = kzalloc(sizeof(*state), GFP_KERNEL);
if (state == NULL)
return NULL;
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.
*/
static 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 = get_unaligned_be16(ibuf + PPP_HDRLEN);
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));