diff options
Diffstat (limited to 'drivers/net/ppp/ppp_deflate.c')
| -rw-r--r-- | drivers/net/ppp/ppp_deflate.c | 635 |
1 files changed, 635 insertions, 0 deletions
diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c new file mode 100644 index 000000000..e6d48e5c6 --- /dev/null +++ b/drivers/net/ppp/ppp_deflate.c @@ -0,0 +1,635 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ppp_deflate.c - interface the zlib procedures for Deflate compression + * and decompression (as used by gzip) to the PPP code. + * + * Copyright 1994-1998 Paul Mackerras. + */ + +#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 && olen <= osize) { + 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) { + vfree(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 = vmalloc(zlib_inflate_workspacesize()); + 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 rc; + + rc = ppp_register_compressor(&ppp_deflate); + if (rc) + return rc; + + rc = ppp_register_compressor(&ppp_deflate_draft); + if (rc) { + ppp_unregister_compressor(&ppp_deflate); + return rc; + } + + pr_info("PPP Deflate Compression module registered\n"); + return 0; +} + +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)); |