/*-
* Copyright (c) 2006 Alexander Motin <mav@alkar.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Predictor-1 PPP compression netgraph node type.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_pred1.h>
#include "opt_netgraph.h"
MALLOC_DEFINE(M_NETGRAPH_PRED1, "netgraph_pred1", "netgraph pred1 node ");
/* PRED1 header length */
#define PRED1_HDRLEN 2
#define PRED1_TABLE_SIZE 0x10000
#define PRED1_BUF_SIZE 4096
#define PPP_INITFCS 0xffff /* Initial FCS value */
#define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
/*
* The following hash code is the heart of the algorithm:
* it builds a sliding hash sum of the previous 3-and-a-bit
* characters which will be used to index the guess table.
* A better hash function would result in additional compression,
* at the expense of time.
*/
#define HASH(x) priv->Hash = (priv->Hash << 4) ^ (x)
/* Node private data */
struct ng_pred1_private {
struct ng_pred1_config cfg; /* configuration */
u_char GuessTable[PRED1_TABLE_SIZE]; /* dictionary */
u_char inbuf[PRED1_BUF_SIZE]; /* input buffer */
u_char outbuf[PRED1_BUF_SIZE]; /* output buffer */
struct ng_pred1_stats stats; /* statistics */
uint16_t Hash;
ng_ID_t ctrlnode; /* path to controlling node */
uint16_t seqnum; /* sequence number */
u_char compress; /* compress/decompress flag */
};
typedef struct ng_pred1_private *priv_p;
/* Netgraph node methods */
static ng_constructor_t ng_pred1_constructor;
static ng_rcvmsg_t ng_pred1_rcvmsg;
static ng_shutdown_t ng_pred1_shutdown;
static ng_newhook_t ng_pred1_newhook;
static ng_rcvdata_t ng_pred1_rcvdata;
static ng_disconnect_t ng_pred1_disconnect;
/* Helper functions */
static int ng_pred1_compress(node_p node, struct mbuf *m,
struct mbuf **resultp);
static int ng_pred1_decompress(node_p node, struct mbuf *m,
struct mbuf **resultp);
static void Pred1Init(node_p node);
static int Pred1Compress(node_p node, u_char *source, u_char *dest,
int len);
static int Pred1Decompress(node_p node, u_char *source, u_char *dest,
int slen, int dlen);
static void Pred1SyncTable(node_p node, u_char *source, int len);
static uint16_t Crc16(uint16_t fcs, u_char *cp, int len);
static const uint16_t Crc16Table[];
/* Parse type for struct ng_pred1_config. */
static const struct ng_parse_struct_field ng_pred1_config_type_fields[]
= NG_PRED1_CONFIG_INFO;
static const struct ng_parse_type ng_pred1_config_type = {
&ng_parse_struct_type,
ng_pred1_config_type_fields
};
/* Parse type for struct ng_pred1_stat. */
static const struct ng_parse_struct_field ng_pred1_stats_type_fields[]
= NG_PRED1_STATS_INFO;
static const struct ng_parse_type ng_pred1_stat_type = {
&ng_parse_struct_type,
ng_pred1_stats_type_fields
};
/* List of commands and how to convert arguments to/from ASCII. */
static const struct ng_cmdlist ng_pred1_cmds[] = {
{
NGM_PRED1_COOKIE,
NGM_PRED1_CONFIG,
"config",
&ng_pred1_config_type,
NULL
},
{
NGM_PRED1_COOKIE,
NGM_PRED1_RESETREQ,
"resetreq",
NULL,
NULL
},
{
NGM_PRED1_COOKIE,
NGM_PRED1_GET_STATS,
"getstats",
NULL,
&ng_pred1_stat_type
},
{
NGM_PRED1_COOKIE,
NGM_PRED1_CLR_STATS,
"clrstats",
NULL,
NULL
},
{
NGM_PRED1_COOKIE,
NGM_PRED1_GETCLR_STATS,
"getclrstats",
NULL,
&ng_pred1_stat_type
},
{ 0 }
};
/* Node type descriptor */
static struct ng_type ng_pred1_typestruct = {
.version = NG_ABI_VERSION,
.name = NG_PRED1_NODE_TYPE,
.constructor = ng_pred1_constructor,
.rcvmsg = ng_pred1_rcvmsg,
.shutdown = ng_pred1_shutdown,
.newhook = ng_pred1_newhook,
.rcvdata = ng_pred1_rcvdata,
.disconnect = ng_pred1_disconnect,
.cmdlist = ng_pred1_cmds,
};
NETGRAPH_INIT(pred1, &ng_pred1_typestruct);
#define ERROUT(x) do { error = (x); goto done; } while (0)
/************************************************************************
NETGRAPH NODE STUFF
************************************************************************/
/*
* Node type constructor
*/
static int
ng_pred1_constructor(node_p node)
{
priv_p priv;
/* Allocate private structure. */
priv = malloc(sizeof(*priv), M_NETGRAPH_PRED1, M_WAITOK | M_ZERO);
NG_NODE_SET_PRIVATE(node, priv);
/* This node is not thread safe. */
NG_NODE_FORCE_WRITER(node);
/* Done */
return (0);
}
/*
* Give our OK for a hook to be added.
*/
static int
ng_pred1_newhook(node_p node, hook_p hook, const char *name)
{
const priv_p priv = NG_NODE_PRIVATE(node);
if (NG_NODE_NUMHOOKS(node) > 0)
return (EINVAL);
if (strcmp(name, NG_PRED1_HOOK_COMP) == 0)
priv->compress = 1;
else if (strcmp(name, NG_PRED1_HOOK_DECOMP) == 0)
priv->compress = 0;
else
return (EINVAL);
return (0);
}
/*
* Receive a control message.
*/
static int
ng_pred1_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
const priv_p priv = NG_NODE_PRIVATE(node);
struct ng_mesg *resp = NULL;
int error = 0;
struct ng_mesg *msg;
NGI_GET_MSG(item, msg);
if (msg->header.typecookie != NGM_PRED1_COOKIE)
ERROUT(EINVAL);
switch (msg->header.cmd) {
case NGM_PRED1_CONFIG:
{
struct ng_pred1_config *const cfg =
(struct ng_pred1_config *)msg->data;
/* Check configuration. */
if (msg->header.arglen != sizeof(*cfg))
ERROUT(EINVAL);
/* Configuration is OK, reset to it. */
priv->cfg = *cfg;
/* Save return address so we can send reset-req's. */
priv->ctrlnode = NGI_RETADDR(item);
/* Clear our state. */
Pred1Init(node);
break;
}
case NGM_PRED1_RESETREQ:
Pred1Init(node);
break;
case NGM_PRED1_GET_STATS:
case NGM_PRED1_CLR_STATS:
case NGM_PRED1_GETCLR_STATS:
{
/* Create response. */
if (msg->header.cmd != NGM_PRED1_CLR_STATS) {
NG_MKRESPONSE(resp, msg,
sizeof(struct ng_pred1_stats), M_NOWAIT);
if (resp == NULL)
ERROUT(ENOMEM);
bcopy(&priv->stats, resp->data,
sizeof(struct ng_pred1_stats));
}
if (msg->header.cmd != NGM_PRED1_GET_STATS)
bzero(&priv->stats, sizeof(struct ng_pred1_stats));
break;
}
default:
error = EINVAL;
break;
}
done:
NG_RESPOND_MSG(error, node, item, resp);
NG_FREE_MSG(msg);
return (error);
}
/*
* Receive incoming data on our hook.
*/
static int
ng_pred1_rcvdata(hook_p hook, item_p item)
{
const node_p node = NG_HOOK_NODE(hook);
const priv_p priv = NG_NODE_PRIVATE(node);
struct mbuf *m, *out;
int error;
if (!priv->cfg.enable) {
NG_FREE_ITEM(item);
return (ENXIO);
}
NGI_GET_M(item, m);
/* Compress. */
if (priv->compress) {
if ((error = ng_pred1_compress(node, m, &out)) != 0) {
NG_FREE_ITEM(item);
log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
return (error);
}
} else { /* Decompress. */
if ((error = ng_pred1_decompress(node, m, &out)) != 0) {
NG_FREE_ITEM(item);
log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
if (priv->ctrlnode != 0) {
struct ng_mesg *msg;
/* Need to send a reset-request. */
NG_MKMESSAGE(msg, NGM_PRED1_COOKIE,
NGM_PRED1_RESETREQ, 0, M_NOWAIT);
if (msg == NULL)
return (error);
NG_SEND_MSG_ID(error, node, msg,
priv->ctrlnode, 0);
}
return (error);
}
}
NG_FWD_NEW_DATA(error, item, hook, out);
return (error);
}
/*
* Destroy node.
*/
static int
ng_pred1_shutdown(node_p node)
{
const priv_p priv = NG_NODE_PRIVATE(node);
free(priv, M_NETGRAPH_PRED1);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_UNREF(node); /* Let the node escape. */
return (0);
}
/*
* Hook disconnection
*/
static int
ng_pred1_disconnect(hook_p hook)
{
const node_p node = NG_HOOK_NODE(hook);
Pred1Init(node);
/* Go away if no longer connected. */
if ((NG_NODE_NUMHOOKS(node) == 0) && NG_NODE_IS_VALID(node))
ng_rmnode_self(node);
return (0);
}
/************************************************************************
HELPER STUFF
************************************************************************/
/*
* Compress/encrypt a packet and put the result in a new mbuf at *resultp.
* The original mbuf is not free'd.
*/
static int
ng_pred1_compress(node_p node, struct mbuf *m, struct mbuf **resultp)
{
const priv_p priv = NG_NODE_PRIVATE(node);
int outlen, inlen;
u_char *out;
uint16_t fcs, lenn;
int len;
/* Initialize. */
*resultp = NULL;
inlen = m->m_pkthdr.len;
priv->stats.FramesPlain++;
priv->stats.InOctets += inlen;
/* Reserve space for expansion. */
if (inlen > (PRED1_BUF_SIZE*8/9 + 1 + 4)) {
priv->stats.Errors++;
NG_FREE_M(m);
return (ENOMEM);
}
/* We must own the mbuf chain exclusively to modify it. */
m = m_unshare(m, M_DONTWAIT);
if (m == NULL) {
priv->stats.Errors++;
return (ENOMEM);
}
/* Work with contiguous regions of memory. */
m_copydata(m, 0, inlen, (caddr_t)(priv->inbuf + 2));
lenn = htons(inlen & 0x7FFF);
/* Compute FCS. */
fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
fcs = Crc16(fcs, priv->inbuf + 2, inlen);
fcs = ~fcs;
/* Compress data. */
len = Pred1Compress(node, priv->inbuf + 2, priv->outbuf + 2, inlen);
/* What happened? */
if (len < inlen) {
out = priv->outbuf;
outlen = 2 + len;
*(uint16_t *)out = lenn;
*out |= 0x80;
priv->stats.FramesComp++;
} else {
out = priv->inbuf;
outlen = 2 + inlen;
*(uint16_t *)out = lenn;
priv->stats.FramesUncomp++;
}
/* Add FCS. */
(out + outlen)[0] = fcs & 0xFF;
(out + outlen)[1] = fcs >> 8;
/* Calculate resulting size. */
outlen += 2;
/* Return packet in an mbuf. */
m_copyback(m, 0, outlen, (caddr_t)out);
if (m->m_pkthdr.len < outlen) {
m_freem(m);
priv->stats.Errors++;
return (ENOMEM);
} else if (outlen < m->m_pkthdr.len)
m_adj(m, outlen - m->m_pkthdr.len);
*resultp = m;
priv->stats.OutOctets += outlen;
return (0);
}
/*
* Decompress/decrypt packet and put the result in a new mbuf at *resultp.
* The original mbuf is not free'd.
*/
static int
ng_pred1_decompress(node_p node, struct mbuf *m, struct mbuf **resultp)
{
const priv_p priv = NG_NODE_PRIVATE(node);
int inlen;
uint16_t len, len1, cf, lenn;
uint16_t fcs;
/* Initialize. */
*resultp = NULL;
inlen = m->m_pkthdr.len;
if (inlen > PRED1_BUF_SIZE) {
priv->stats.Errors++;
NG_FREE_M(m);
return (ENOMEM);
}
/* We must own the mbuf chain exclusively to modify it. */
m = m_unshare(m, M_DONTWAIT);
if (m == NULL) {
priv->stats.Errors++;
return (ENOMEM);
}
/* Work with contiguous regions of memory. */
m_copydata(m, 0, inlen, (caddr_t)priv->inbuf);
priv->stats.InOctets += inlen;
/* Get initial length value. */
len = priv->inbuf[0] << 8;
len += priv->inbuf[1];
cf = (len & 0x8000);
len &= 0x7fff;
/* Is data compressed or not really? */
if (cf) {
priv->stats.FramesComp++;
len1 = Pred1Decompress(node, priv->inbuf + 2, priv->outbuf,
inlen - 4, PRED1_BUF_SIZE);
if (len != len1) {
/* Error is detected. Send reset request */
m_freem(m);
priv->stats.Errors++;
log(LOG_NOTICE, "ng_pred1: Comp length error (%d) "
"--> len (%d)\n", len, len1);
return (EIO);
}
/*
* CRC check on receive is defined in RFC. It is surely required
* for compressed frames to signal dictionary corruption,
* but it is actually useless for uncompressed frames because
* the same check has already done by HDLC and/or other layer.
*/
lenn = htons(len);
fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
fcs = Crc16(fcs, priv->outbuf, len);
fcs = Crc16(fcs, priv->inbuf + inlen - 2, 2);
if (fcs != PPP_GOODFCS) {
m_freem(m);
priv->stats.Errors++;
log(LOG_NOTICE, "ng_pred1: Pred1: Bad CRC-16\n");
return (EIO);
}
/* Return packet in an mbuf. */
m_copyback(m, 0, len, (caddr_t)priv->outbuf);
if (m->m_pkthdr.len < len) {
m_freem(m);
priv->stats.Errors++;
return (ENOMEM);
} else if (len < m->m_pkthdr.len)
m_adj(m, len - m->m_pkthdr.len);
*resultp = m;
} else {
priv->stats.FramesUncomp++;
if (len != (inlen - 4)) {
/* Wrong length. Send reset request */
priv->stats.Errors++;
log(LOG_NOTICE, "ng_pred1: Uncomp length error (%d) "
"--> len (%d)\n", len, inlen - 4);
NG_FREE_M(m);
return (EIO);
}
Pred1SyncTable(node, priv->inbuf + 2, len);
m_adj(m, 2); /* Strip length. */
m_adj(m, -2); /* Strip fcs. */
*resultp = m;
}
priv->stats.FramesPlain++;
priv->stats.OutOctets += len;
return (0);
}
/*
* Pred1Init()
*/
static void
Pred1Init(node_p node)
{
const priv_p priv = NG_NODE_PRIVATE(node);
priv->Hash = 0;
memset(priv->GuessTable, 0, PRED1_TABLE_SIZE);
}
/*
* Pred1Compress()
*/
static int
Pred1Compress(node_p node, u_char *source, u_char *dest, int len)
{
const priv_p priv = NG_NODE_PRIVATE(node);
int i;
u_char flags;
u_char *flagdest, *orgdest;
orgdest = dest;
while (len) {
flagdest = dest++;
flags = 0; /* All guesses are wrong initially. */
for (i = 0; i < 8 && len; i++) {
if (priv->GuessTable[priv->Hash] == *source)
/* Guess was right - don't output. */
flags |= (1 << i);
else {
/* Guess wrong, output char. */
priv->GuessTable[priv->Hash] = *source;
*dest++ = *source;
}
HASH(*source++);
len--;
}
*flagdest = flags;
}
return (dest - orgdest);
}
/*
* Pred1Decompress()
*
* Returns decompressed size, or -1 if we ran out of space.
*/
static int
Pred1Decompress(node_p node, u_char *source, u_char *dest, int slen, int dlen)
{
const priv_p priv = NG_NODE_PRIVATE(node);
int i;
u_char flags, *orgdest;
orgdest = dest;
while (slen) {
flags = *source++;
slen--;
for (i = 0; i < 8; i++, flags >>= 1) {
if (dlen <= 0)
return(-1);
if (flags & 0x01)
/* Guess correct */
*dest = priv->GuessTable[priv->Hash];
else {
if (!slen)
/* We seem to be really done -- cabo. */
break;
/* Guess wrong. */
priv->GuessTable[priv->Hash] = *source;
/* Read from source. */
*dest = *source++;
slen--;
}
HASH(*dest++);
dlen--;
}
}
return (dest - orgdest);
}
/*
* Pred1SyncTable()
*/
static void
Pred1SyncTable(node_p node, u_char *source, int len)
{
const priv_p priv = NG_NODE_PRIVATE(node);
while (len--) {
priv->GuessTable[priv->Hash] = *source;
HASH(*source++);
}
}
/*
* Crc16()
*
* Compute the 16 bit frame check value, per RFC 1171 Appendix B,
* on an array of bytes.
*/
static uint16_t
Crc16(uint16_t crc, u_char *cp, int len)
{
while (len--)
crc = (crc >> 8) ^ Crc16Table[(crc ^ *cp++) & 0xff];
return (crc);
}
static const uint16_t Crc16Table[256] = {
/* 00 */ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
/* 08 */ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
/* 10 */ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
/* 18 */ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
/* 20 */ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
/* 28 */ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
/* 30 */ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
/* 38 */ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
/* 40 */ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
/* 48 */ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
/* 50 */ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
/* 58 */ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
/* 60 */ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
/* 68 */ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
/* 70 */ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
/* 78 */ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
/* 80 */ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
/* 88 */ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
/* 90 */ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
/* 98 */ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
/* a0 */ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
/* a8 */ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
/* b0 */ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
/* b8 */ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
/* c0 */ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
/* c8 */ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
/* d0 */ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
/* d8 */ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
/* e0 */ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
/* e8 */ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
/* f0 */ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
/* f8 */ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
