2 * Copyright (c) 2006 Alexander Motin <mav@alkar.net>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * $FreeBSD: src/sys/netgraph/ng_pred1.c,v 1.3 2008/01/27 02:04:12 mav Exp $
28 * $DragonFly: src/sys/netgraph7/ng_pred1.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
32 * Predictor-1 PPP compression netgraph node type.
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/errno.h>
41 #include <sys/syslog.h>
43 #include "ng_message.h"
48 #include "opt_netgraph.h"
50 MALLOC_DEFINE(M_NETGRAPH_PRED1, "netgraph_pred1", "netgraph pred1 node ");
52 /* PRED1 header length */
53 #define PRED1_HDRLEN 2
55 #define PRED1_TABLE_SIZE 0x10000
56 #define PRED1_BUF_SIZE 4096
57 #define PPP_INITFCS 0xffff /* Initial FCS value */
58 #define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
61 * The following hash code is the heart of the algorithm:
62 * it builds a sliding hash sum of the previous 3-and-a-bit
63 * characters which will be used to index the guess table.
64 * A better hash function would result in additional compression,
65 * at the expense of time.
68 #define HASH(x) priv->Hash = (priv->Hash << 4) ^ (x)
70 /* Node private data */
71 struct ng_pred1_private {
72 struct ng_pred1_config cfg; /* configuration */
73 u_char GuessTable[PRED1_TABLE_SIZE]; /* dictionary */
74 u_char inbuf[PRED1_BUF_SIZE]; /* input buffer */
75 u_char outbuf[PRED1_BUF_SIZE]; /* output buffer */
76 struct ng_pred1_stats stats; /* statistics */
78 ng_ID_t ctrlnode; /* path to controlling node */
79 uint16_t seqnum; /* sequence number */
80 u_char compress; /* compress/decompress flag */
82 typedef struct ng_pred1_private *priv_p;
84 /* Netgraph node methods */
85 static ng_constructor_t ng_pred1_constructor;
86 static ng_rcvmsg_t ng_pred1_rcvmsg;
87 static ng_shutdown_t ng_pred1_shutdown;
88 static ng_newhook_t ng_pred1_newhook;
89 static ng_rcvdata_t ng_pred1_rcvdata;
90 static ng_disconnect_t ng_pred1_disconnect;
92 /* Helper functions */
93 static int ng_pred1_compress(node_p node, struct mbuf *m,
94 struct mbuf **resultp);
95 static int ng_pred1_decompress(node_p node, struct mbuf *m,
96 struct mbuf **resultp);
97 static void Pred1Init(node_p node);
98 static int Pred1Compress(node_p node, u_char *source, u_char *dest,
100 static int Pred1Decompress(node_p node, u_char *source, u_char *dest,
102 static void Pred1SyncTable(node_p node, u_char *source, int len);
103 static uint16_t Crc16(uint16_t fcs, u_char *cp, int len);
105 static const uint16_t Crc16Table[];
107 /* Parse type for struct ng_pred1_config. */
108 static const struct ng_parse_struct_field ng_pred1_config_type_fields[]
109 = NG_PRED1_CONFIG_INFO;
110 static const struct ng_parse_type ng_pred1_config_type = {
111 &ng_parse_struct_type,
112 ng_pred1_config_type_fields
115 /* Parse type for struct ng_pred1_stat. */
116 static const struct ng_parse_struct_field ng_pred1_stats_type_fields[]
117 = NG_PRED1_STATS_INFO;
118 static const struct ng_parse_type ng_pred1_stat_type = {
119 &ng_parse_struct_type,
120 ng_pred1_stats_type_fields
123 /* List of commands and how to convert arguments to/from ASCII. */
124 static const struct ng_cmdlist ng_pred1_cmds[] = {
129 &ng_pred1_config_type,
155 NGM_PRED1_GETCLR_STATS,
163 /* Node type descriptor */
164 static struct ng_type ng_pred1_typestruct = {
165 .version = NG_ABI_VERSION,
166 .name = NG_PRED1_NODE_TYPE,
167 .constructor = ng_pred1_constructor,
168 .rcvmsg = ng_pred1_rcvmsg,
169 .shutdown = ng_pred1_shutdown,
170 .newhook = ng_pred1_newhook,
171 .rcvdata = ng_pred1_rcvdata,
172 .disconnect = ng_pred1_disconnect,
173 .cmdlist = ng_pred1_cmds,
175 NETGRAPH_INIT(pred1, &ng_pred1_typestruct);
177 #define ERROUT(x) do { error = (x); goto done; } while (0)
179 /************************************************************************
181 ************************************************************************/
184 * Node type constructor
187 ng_pred1_constructor(node_p node)
191 /* Allocate private structure. */
192 priv = kmalloc(sizeof(*priv), M_NETGRAPH_PRED1, M_WAITOK | M_ZERO);
194 NG_NODE_SET_PRIVATE(node, priv);
196 /* This node is not thread safe. */
197 NG_NODE_FORCE_WRITER(node);
204 * Give our OK for a hook to be added.
207 ng_pred1_newhook(node_p node, hook_p hook, const char *name)
209 const priv_p priv = NG_NODE_PRIVATE(node);
211 if (NG_NODE_NUMHOOKS(node) > 0)
214 if (strcmp(name, NG_PRED1_HOOK_COMP) == 0)
216 else if (strcmp(name, NG_PRED1_HOOK_DECOMP) == 0)
225 * Receive a control message.
228 ng_pred1_rcvmsg(node_p node, item_p item, hook_p lasthook)
230 const priv_p priv = NG_NODE_PRIVATE(node);
231 struct ng_mesg *resp = NULL;
235 NGI_GET_MSG(item, msg);
237 if (msg->header.typecookie != NGM_PRED1_COOKIE)
240 switch (msg->header.cmd) {
241 case NGM_PRED1_CONFIG:
243 struct ng_pred1_config *const cfg =
244 (struct ng_pred1_config *)msg->data;
246 /* Check configuration. */
247 if (msg->header.arglen != sizeof(*cfg))
250 /* Configuration is OK, reset to it. */
253 /* Save return address so we can send reset-req's. */
254 priv->ctrlnode = NGI_RETADDR(item);
256 /* Clear our state. */
261 case NGM_PRED1_RESETREQ:
265 case NGM_PRED1_GET_STATS:
266 case NGM_PRED1_CLR_STATS:
267 case NGM_PRED1_GETCLR_STATS:
269 /* Create response. */
270 if (msg->header.cmd != NGM_PRED1_CLR_STATS) {
271 NG_MKRESPONSE(resp, msg,
272 sizeof(struct ng_pred1_stats), M_WAITOK | M_NULLOK);
275 bcopy(&priv->stats, resp->data,
276 sizeof(struct ng_pred1_stats));
279 if (msg->header.cmd != NGM_PRED1_GET_STATS)
280 bzero(&priv->stats, sizeof(struct ng_pred1_stats));
289 NG_RESPOND_MSG(error, node, item, resp);
295 * Receive incoming data on our hook.
298 ng_pred1_rcvdata(hook_p hook, item_p item)
300 const node_p node = NG_HOOK_NODE(hook);
301 const priv_p priv = NG_NODE_PRIVATE(node);
302 struct mbuf *m, *out;
305 if (!priv->cfg.enable) {
312 if (priv->compress) {
313 if ((error = ng_pred1_compress(node, m, &out)) != 0) {
315 log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
319 } else { /* Decompress. */
320 if ((error = ng_pred1_decompress(node, m, &out)) != 0) {
322 log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
323 if (priv->ctrlnode != 0) {
326 /* Need to send a reset-request. */
327 NG_MKMESSAGE(msg, NGM_PRED1_COOKIE,
328 NGM_PRED1_RESETREQ, 0, M_WAITOK | M_NULLOK);
331 NG_SEND_MSG_ID(error, node, msg,
338 NG_FWD_NEW_DATA(error, item, hook, out);
346 ng_pred1_shutdown(node_p node)
348 const priv_p priv = NG_NODE_PRIVATE(node);
350 kfree(priv, M_NETGRAPH_PRED1);
351 NG_NODE_SET_PRIVATE(node, NULL);
352 NG_NODE_UNREF(node); /* Let the node escape. */
360 ng_pred1_disconnect(hook_p hook)
362 const node_p node = NG_HOOK_NODE(hook);
366 /* Go away if no longer connected. */
367 if ((NG_NODE_NUMHOOKS(node) == 0) && NG_NODE_IS_VALID(node))
368 ng_rmnode_self(node);
372 /************************************************************************
374 ************************************************************************/
377 * Compress/encrypt a packet and put the result in a new mbuf at *resultp.
378 * The original mbuf is not free'd.
381 ng_pred1_compress(node_p node, struct mbuf *m, struct mbuf **resultp)
383 const priv_p priv = NG_NODE_PRIVATE(node);
392 inlen = m->m_pkthdr.len;
394 priv->stats.FramesPlain++;
395 priv->stats.InOctets += inlen;
397 /* Reserve space for expansion. */
398 if (inlen > (PRED1_BUF_SIZE*8/9 + 1 + 4)) {
399 priv->stats.Errors++;
404 /* Work with contiguous regions of memory. */
405 m_copydata(m, 0, inlen, (caddr_t)(priv->inbuf + 2));
409 lenn = htons(inlen & 0x7FFF);
412 fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
413 fcs = Crc16(fcs, priv->inbuf + 2, inlen);
417 len = Pred1Compress(node, priv->inbuf + 2, priv->outbuf + 2, inlen);
423 *(uint16_t *)out = lenn;
425 priv->stats.FramesComp++;
429 *(uint16_t *)out = lenn;
430 priv->stats.FramesUncomp++;
434 (out + outlen)[0] = fcs & 0xFF;
435 (out + outlen)[1] = fcs >> 8;
437 /* Calculate resulting size. */
440 /* Return packet in an mbuf. */
441 *resultp = m_devget((caddr_t)out, outlen, 0, NULL, NULL);
442 if (*resultp == NULL) {
443 priv->stats.Errors++;
447 priv->stats.OutOctets += outlen;
453 * Decompress/decrypt packet and put the result in a new mbuf at *resultp.
454 * The original mbuf is not free'd.
457 ng_pred1_decompress(node_p node, struct mbuf *m, struct mbuf **resultp)
459 const priv_p priv = NG_NODE_PRIVATE(node);
461 uint16_t len, len1, cf, lenn;
467 inlen = m->m_pkthdr.len;
469 if (inlen > PRED1_BUF_SIZE) {
470 priv->stats.Errors++;
475 /* Work with contiguous regions of memory. */
476 m_copydata(m, 0, inlen, (caddr_t)priv->inbuf);
478 priv->stats.InOctets += inlen;
480 /* Get initial length value. */
481 len = priv->inbuf[0] << 8;
482 len += priv->inbuf[1];
487 /* Is data compressed or not really? */
491 priv->stats.FramesComp++;
492 len1 = Pred1Decompress(node, priv->inbuf + 2, priv->outbuf,
493 inlen - 4, PRED1_BUF_SIZE);
495 /* Error is detected. Send reset request */
496 priv->stats.Errors++;
497 log(LOG_NOTICE, "ng_pred1: Comp length error (%d) "
498 "--> len (%d)\n", len, len1);
503 * CRC check on receive is defined in RFC. It is surely required
504 * for compressed frames to signal dictionary corruption,
505 * but it is actually useless for uncompressed frames because
506 * the same check has already done by HDLC and/or other layer.
509 fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
510 fcs = Crc16(fcs, priv->outbuf, len);
511 fcs = Crc16(fcs, priv->inbuf + inlen - 2, 2);
513 if (fcs != PPP_GOODFCS) {
514 priv->stats.Errors++;
515 log(LOG_NOTICE, "ng_pred1: Pred1: Bad CRC-16\n");
519 /* Return packet in an mbuf. */
520 *resultp = m_devget((caddr_t)priv->outbuf, len, 0, NULL, NULL);
521 if (*resultp == NULL) {
522 priv->stats.Errors++;
527 priv->stats.FramesUncomp++;
528 if (len != (inlen - 4)) {
529 /* Wrong length. Send reset request */
530 priv->stats.Errors++;
531 log(LOG_NOTICE, "ng_pred1: Uncomp length error (%d) "
532 "--> len (%d)\n", len, inlen - 4);
536 Pred1SyncTable(node, priv->inbuf + 2, len);
537 m_adj(m, 2); /* Strip length. */
538 m_adj(m, -2); /* Strip fcs. */
542 priv->stats.FramesPlain++;
543 priv->stats.OutOctets += len;
553 Pred1Init(node_p node)
555 const priv_p priv = NG_NODE_PRIVATE(node);
558 memset(priv->GuessTable, 0, PRED1_TABLE_SIZE);
566 Pred1Compress(node_p node, u_char *source, u_char *dest, int len)
568 const priv_p priv = NG_NODE_PRIVATE(node);
571 u_char *flagdest, *orgdest;
576 flags = 0; /* All guesses are wrong initially. */
577 for (i = 0; i < 8 && len; i++) {
578 if (priv->GuessTable[priv->Hash] == *source)
579 /* Guess was right - don't output. */
582 /* Guess wrong, output char. */
583 priv->GuessTable[priv->Hash] = *source;
591 return (dest - orgdest);
597 * Returns decompressed size, or -1 if we ran out of space.
601 Pred1Decompress(node_p node, u_char *source, u_char *dest, int slen, int dlen)
603 const priv_p priv = NG_NODE_PRIVATE(node);
605 u_char flags, *orgdest;
611 for (i = 0; i < 8; i++, flags >>= 1) {
616 *dest = priv->GuessTable[priv->Hash];
619 /* We seem to be really done -- cabo. */
623 priv->GuessTable[priv->Hash] = *source;
624 /* Read from source. */
632 return (dest - orgdest);
640 Pred1SyncTable(node_p node, u_char *source, int len)
642 const priv_p priv = NG_NODE_PRIVATE(node);
645 priv->GuessTable[priv->Hash] = *source;
653 * Compute the 16 bit frame check value, per RFC 1171 Appendix B,
654 * on an array of bytes.
658 Crc16(uint16_t crc, u_char *cp, int len)
661 crc = (crc >> 8) ^ Crc16Table[(crc ^ *cp++) & 0xff];
665 static const uint16_t Crc16Table[256] = {
666 /* 00 */ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
667 /* 08 */ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
668 /* 10 */ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
669 /* 18 */ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
670 /* 20 */ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
671 /* 28 */ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
672 /* 30 */ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
673 /* 38 */ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
674 /* 40 */ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
675 /* 48 */ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
676 /* 50 */ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
677 /* 58 */ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
678 /* 60 */ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
679 /* 68 */ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
680 /* 70 */ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
681 /* 78 */ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
682 /* 80 */ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
683 /* 88 */ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
684 /* 90 */ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
685 /* 98 */ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
686 /* a0 */ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
687 /* a8 */ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
688 /* b0 */ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
689 /* b8 */ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
690 /* c0 */ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
691 /* c8 */ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
692 /* d0 */ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
693 /* d8 */ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
694 /* e0 */ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
695 /* e8 */ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
696 /* f0 */ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
697 /* f8 */ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78