2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2006 Alexander Motin <mav@alkar.net>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * Predictor-1 PPP compression netgraph node type.
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/errno.h>
42 #include <sys/syslog.h>
44 #include <netgraph/ng_message.h>
45 #include <netgraph/netgraph.h>
46 #include <netgraph/ng_parse.h>
47 #include <netgraph/ng_pred1.h>
49 #include "opt_netgraph.h"
51 static MALLOC_DEFINE(M_NETGRAPH_PRED1, "netgraph_pred1", "netgraph pred1 node");
53 /* PRED1 header length */
54 #define PRED1_HDRLEN 2
56 #define PRED1_TABLE_SIZE 0x10000
57 #define PRED1_BUF_SIZE 4096
58 #define PPP_INITFCS 0xffff /* Initial FCS value */
59 #define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
62 * The following hash code is the heart of the algorithm:
63 * it builds a sliding hash sum of the previous 3-and-a-bit
64 * characters which will be used to index the guess table.
65 * A better hash function would result in additional compression,
66 * at the expense of time.
69 #define HASH(x) priv->Hash = (priv->Hash << 4) ^ (x)
71 /* Node private data */
72 struct ng_pred1_private {
73 struct ng_pred1_config cfg; /* configuration */
74 u_char GuessTable[PRED1_TABLE_SIZE]; /* dictionary */
75 u_char inbuf[PRED1_BUF_SIZE]; /* input buffer */
76 u_char outbuf[PRED1_BUF_SIZE]; /* output buffer */
77 struct ng_pred1_stats stats; /* statistics */
79 ng_ID_t ctrlnode; /* path to controlling node */
80 uint16_t seqnum; /* sequence number */
81 u_char compress; /* compress/decompress flag */
83 typedef struct ng_pred1_private *priv_p;
85 /* Netgraph node methods */
86 static ng_constructor_t ng_pred1_constructor;
87 static ng_rcvmsg_t ng_pred1_rcvmsg;
88 static ng_shutdown_t ng_pred1_shutdown;
89 static ng_newhook_t ng_pred1_newhook;
90 static ng_rcvdata_t ng_pred1_rcvdata;
91 static ng_disconnect_t ng_pred1_disconnect;
93 /* Helper functions */
94 static int ng_pred1_compress(node_p node, struct mbuf *m,
95 struct mbuf **resultp);
96 static int ng_pred1_decompress(node_p node, struct mbuf *m,
97 struct mbuf **resultp);
98 static void Pred1Init(node_p node);
99 static int Pred1Compress(node_p node, u_char *source, u_char *dest,
101 static int Pred1Decompress(node_p node, u_char *source, u_char *dest,
103 static void Pred1SyncTable(node_p node, u_char *source, int len);
104 static uint16_t Crc16(uint16_t fcs, u_char *cp, int len);
106 static const uint16_t Crc16Table[];
108 /* Parse type for struct ng_pred1_config. */
109 static const struct ng_parse_struct_field ng_pred1_config_type_fields[]
110 = NG_PRED1_CONFIG_INFO;
111 static const struct ng_parse_type ng_pred1_config_type = {
112 &ng_parse_struct_type,
113 ng_pred1_config_type_fields
116 /* Parse type for struct ng_pred1_stat. */
117 static const struct ng_parse_struct_field ng_pred1_stats_type_fields[]
118 = NG_PRED1_STATS_INFO;
119 static const struct ng_parse_type ng_pred1_stat_type = {
120 &ng_parse_struct_type,
121 ng_pred1_stats_type_fields
124 /* List of commands and how to convert arguments to/from ASCII. */
125 static const struct ng_cmdlist ng_pred1_cmds[] = {
130 &ng_pred1_config_type,
156 NGM_PRED1_GETCLR_STATS,
164 /* Node type descriptor */
165 static struct ng_type ng_pred1_typestruct = {
166 .version = NG_ABI_VERSION,
167 .name = NG_PRED1_NODE_TYPE,
168 .constructor = ng_pred1_constructor,
169 .rcvmsg = ng_pred1_rcvmsg,
170 .shutdown = ng_pred1_shutdown,
171 .newhook = ng_pred1_newhook,
172 .rcvdata = ng_pred1_rcvdata,
173 .disconnect = ng_pred1_disconnect,
174 .cmdlist = ng_pred1_cmds,
176 NETGRAPH_INIT(pred1, &ng_pred1_typestruct);
178 #define ERROUT(x) do { error = (x); goto done; } while (0)
180 /************************************************************************
182 ************************************************************************/
185 * Node type constructor
188 ng_pred1_constructor(node_p node)
192 /* Allocate private structure. */
193 priv = malloc(sizeof(*priv), M_NETGRAPH_PRED1, M_WAITOK | M_ZERO);
195 NG_NODE_SET_PRIVATE(node, priv);
197 /* This node is not thread safe. */
198 NG_NODE_FORCE_WRITER(node);
205 * Give our OK for a hook to be added.
208 ng_pred1_newhook(node_p node, hook_p hook, const char *name)
210 const priv_p priv = NG_NODE_PRIVATE(node);
212 if (NG_NODE_NUMHOOKS(node) > 0)
215 if (strcmp(name, NG_PRED1_HOOK_COMP) == 0)
217 else if (strcmp(name, NG_PRED1_HOOK_DECOMP) == 0)
226 * Receive a control message.
229 ng_pred1_rcvmsg(node_p node, item_p item, hook_p lasthook)
231 const priv_p priv = NG_NODE_PRIVATE(node);
232 struct ng_mesg *resp = NULL;
236 NGI_GET_MSG(item, msg);
238 if (msg->header.typecookie != NGM_PRED1_COOKIE)
241 switch (msg->header.cmd) {
242 case NGM_PRED1_CONFIG:
244 struct ng_pred1_config *const cfg =
245 (struct ng_pred1_config *)msg->data;
247 /* Check configuration. */
248 if (msg->header.arglen != sizeof(*cfg))
251 /* Configuration is OK, reset to it. */
254 /* Save return address so we can send reset-req's. */
255 priv->ctrlnode = NGI_RETADDR(item);
257 /* Clear our state. */
262 case NGM_PRED1_RESETREQ:
266 case NGM_PRED1_GET_STATS:
267 case NGM_PRED1_CLR_STATS:
268 case NGM_PRED1_GETCLR_STATS:
270 /* Create response. */
271 if (msg->header.cmd != NGM_PRED1_CLR_STATS) {
272 NG_MKRESPONSE(resp, msg,
273 sizeof(struct ng_pred1_stats), M_NOWAIT);
276 bcopy(&priv->stats, resp->data,
277 sizeof(struct ng_pred1_stats));
280 if (msg->header.cmd != NGM_PRED1_GET_STATS)
281 bzero(&priv->stats, sizeof(struct ng_pred1_stats));
290 NG_RESPOND_MSG(error, node, item, resp);
296 * Receive incoming data on our hook.
299 ng_pred1_rcvdata(hook_p hook, item_p item)
301 const node_p node = NG_HOOK_NODE(hook);
302 const priv_p priv = NG_NODE_PRIVATE(node);
303 struct mbuf *m, *out;
306 if (!priv->cfg.enable) {
313 if (priv->compress) {
314 if ((error = ng_pred1_compress(node, m, &out)) != 0) {
316 log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
320 } else { /* Decompress. */
321 if ((error = ng_pred1_decompress(node, m, &out)) != 0) {
323 log(LOG_NOTICE, "%s: error: %d\n", __func__, error);
324 if (priv->ctrlnode != 0) {
327 /* Need to send a reset-request. */
328 NG_MKMESSAGE(msg, NGM_PRED1_COOKIE,
329 NGM_PRED1_RESETREQ, 0, M_NOWAIT);
332 NG_SEND_MSG_ID(error, node, msg,
339 NG_FWD_NEW_DATA(error, item, hook, out);
347 ng_pred1_shutdown(node_p node)
349 const priv_p priv = NG_NODE_PRIVATE(node);
351 free(priv, M_NETGRAPH_PRED1);
352 NG_NODE_SET_PRIVATE(node, NULL);
353 NG_NODE_UNREF(node); /* Let the node escape. */
361 ng_pred1_disconnect(hook_p hook)
363 const node_p node = NG_HOOK_NODE(hook);
367 /* Go away if no longer connected. */
368 if ((NG_NODE_NUMHOOKS(node) == 0) && NG_NODE_IS_VALID(node))
369 ng_rmnode_self(node);
373 /************************************************************************
375 ************************************************************************/
378 * Compress/encrypt a packet and put the result in a new mbuf at *resultp.
379 * The original mbuf is not free'd.
382 ng_pred1_compress(node_p node, struct mbuf *m, struct mbuf **resultp)
384 const priv_p priv = NG_NODE_PRIVATE(node);
393 inlen = m->m_pkthdr.len;
395 priv->stats.FramesPlain++;
396 priv->stats.InOctets += inlen;
398 /* Reserve space for expansion. */
399 if (inlen > (PRED1_BUF_SIZE*8/9 + 1 + 4)) {
400 priv->stats.Errors++;
405 /* We must own the mbuf chain exclusively to modify it. */
406 m = m_unshare(m, M_NOWAIT);
408 priv->stats.Errors++;
412 /* Work with contiguous regions of memory. */
413 m_copydata(m, 0, inlen, (caddr_t)(priv->inbuf + 2));
415 lenn = htons(inlen & 0x7FFF);
418 fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
419 fcs = Crc16(fcs, priv->inbuf + 2, inlen);
423 len = Pred1Compress(node, priv->inbuf + 2, priv->outbuf + 2, inlen);
429 *(uint16_t *)out = lenn;
431 priv->stats.FramesComp++;
435 *(uint16_t *)out = lenn;
436 priv->stats.FramesUncomp++;
440 (out + outlen)[0] = fcs & 0xFF;
441 (out + outlen)[1] = fcs >> 8;
443 /* Calculate resulting size. */
446 /* Return packet in an mbuf. */
447 m_copyback(m, 0, outlen, (caddr_t)out);
448 if (m->m_pkthdr.len < outlen) {
450 priv->stats.Errors++;
452 } else if (outlen < m->m_pkthdr.len)
453 m_adj(m, outlen - m->m_pkthdr.len);
455 priv->stats.OutOctets += outlen;
461 * Decompress/decrypt packet and put the result in a new mbuf at *resultp.
462 * The original mbuf is not free'd.
465 ng_pred1_decompress(node_p node, struct mbuf *m, struct mbuf **resultp)
467 const priv_p priv = NG_NODE_PRIVATE(node);
469 uint16_t len, len1, cf, lenn;
475 inlen = m->m_pkthdr.len;
477 if (inlen > PRED1_BUF_SIZE) {
478 priv->stats.Errors++;
483 /* We must own the mbuf chain exclusively to modify it. */
484 m = m_unshare(m, M_NOWAIT);
486 priv->stats.Errors++;
490 /* Work with contiguous regions of memory. */
491 m_copydata(m, 0, inlen, (caddr_t)priv->inbuf);
493 priv->stats.InOctets += inlen;
495 /* Get initial length value. */
496 len = priv->inbuf[0] << 8;
497 len += priv->inbuf[1];
502 /* Is data compressed or not really? */
504 priv->stats.FramesComp++;
505 len1 = Pred1Decompress(node, priv->inbuf + 2, priv->outbuf,
506 inlen - 4, PRED1_BUF_SIZE);
508 /* Error is detected. Send reset request */
510 priv->stats.Errors++;
511 log(LOG_NOTICE, "ng_pred1: Comp length error (%d) "
512 "--> len (%d)\n", len, len1);
517 * CRC check on receive is defined in RFC. It is surely required
518 * for compressed frames to signal dictionary corruption,
519 * but it is actually useless for uncompressed frames because
520 * the same check has already done by HDLC and/or other layer.
523 fcs = Crc16(PPP_INITFCS, (u_char *)&lenn, 2);
524 fcs = Crc16(fcs, priv->outbuf, len);
525 fcs = Crc16(fcs, priv->inbuf + inlen - 2, 2);
527 if (fcs != PPP_GOODFCS) {
529 priv->stats.Errors++;
530 log(LOG_NOTICE, "ng_pred1: Pred1: Bad CRC-16\n");
534 /* Return packet in an mbuf. */
535 m_copyback(m, 0, len, (caddr_t)priv->outbuf);
536 if (m->m_pkthdr.len < len) {
538 priv->stats.Errors++;
540 } else if (len < m->m_pkthdr.len)
541 m_adj(m, len - m->m_pkthdr.len);
545 priv->stats.FramesUncomp++;
546 if (len != (inlen - 4)) {
547 /* Wrong length. Send reset request */
548 priv->stats.Errors++;
549 log(LOG_NOTICE, "ng_pred1: Uncomp length error (%d) "
550 "--> len (%d)\n", len, inlen - 4);
554 Pred1SyncTable(node, priv->inbuf + 2, len);
555 m_adj(m, 2); /* Strip length. */
556 m_adj(m, -2); /* Strip fcs. */
560 priv->stats.FramesPlain++;
561 priv->stats.OutOctets += len;
571 Pred1Init(node_p node)
573 const priv_p priv = NG_NODE_PRIVATE(node);
576 memset(priv->GuessTable, 0, PRED1_TABLE_SIZE);
584 Pred1Compress(node_p node, u_char *source, u_char *dest, int len)
586 const priv_p priv = NG_NODE_PRIVATE(node);
589 u_char *flagdest, *orgdest;
594 flags = 0; /* All guesses are wrong initially. */
595 for (i = 0; i < 8 && len; i++) {
596 if (priv->GuessTable[priv->Hash] == *source)
597 /* Guess was right - don't output. */
600 /* Guess wrong, output char. */
601 priv->GuessTable[priv->Hash] = *source;
609 return (dest - orgdest);
615 * Returns decompressed size, or -1 if we ran out of space.
619 Pred1Decompress(node_p node, u_char *source, u_char *dest, int slen, int dlen)
621 const priv_p priv = NG_NODE_PRIVATE(node);
623 u_char flags, *orgdest;
629 for (i = 0; i < 8; i++, flags >>= 1) {
634 *dest = priv->GuessTable[priv->Hash];
637 /* We seem to be really done -- cabo. */
641 priv->GuessTable[priv->Hash] = *source;
642 /* Read from source. */
650 return (dest - orgdest);
658 Pred1SyncTable(node_p node, u_char *source, int len)
660 const priv_p priv = NG_NODE_PRIVATE(node);
663 priv->GuessTable[priv->Hash] = *source;
671 * Compute the 16 bit frame check value, per RFC 1171 Appendix B,
672 * on an array of bytes.
676 Crc16(uint16_t crc, u_char *cp, int len)
679 crc = (crc >> 8) ^ Crc16Table[(crc ^ *cp++) & 0xff];
683 static const uint16_t Crc16Table[256] = {
684 /* 00 */ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
685 /* 08 */ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
686 /* 10 */ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
687 /* 18 */ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
688 /* 20 */ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
689 /* 28 */ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
690 /* 30 */ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
691 /* 38 */ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
692 /* 40 */ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
693 /* 48 */ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
694 /* 50 */ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
695 /* 58 */ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
696 /* 60 */ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
697 /* 68 */ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
698 /* 70 */ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
699 /* 78 */ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
700 /* 80 */ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
701 /* 88 */ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
702 /* 90 */ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
703 /* 98 */ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
704 /* a0 */ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
705 /* a8 */ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
706 /* b0 */ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
707 /* b8 */ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
708 /* c0 */ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
709 /* c8 */ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
710 /* d0 */ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
711 /* d8 */ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
712 /* e0 */ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
713 /* e8 */ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
714 /* f0 */ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
715 /* f8 */ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78