1
2/*
3 * ng_frame_relay.c
4 *
5 * Copyright (c) 1996-1999 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Author: Julian Elisher <julian@freebsd.org>
38 *
|
39 * $FreeBSD: head/sys/netgraph/ng_frame_relay.c 68876 2000-11-18 15:17:43Z dwmalone $
|
| 39 * $FreeBSD: head/sys/netgraph/ng_frame_relay.c 69922 2000-12-12 18:52:14Z julian $ |
40 * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
41 */
42
43/*
44 * This node implements the frame relay protocol, not including
45 * the LMI line management. This means basically keeping track
46 * of which DLCI's are active, doing frame (de)multiplexing, etc.
47 *
48 * It has a 'downstream' hook that goes to the line, and a
49 * hook for each DLCI (eg, 'dlci16').
50 */
51
52#include <sys/param.h>
53#include <sys/systm.h>
54#include <sys/kernel.h>
55#include <sys/errno.h>
56#include <sys/malloc.h>
57#include <sys/mbuf.h>
58#include <sys/syslog.h>
59#include <sys/ctype.h>
60
61#include <netgraph/ng_message.h>
62#include <netgraph/netgraph.h>
63#include <netgraph/ng_frame_relay.h>
64
65/*
66 * Line info, and status per channel.
67 */
68struct ctxinfo { /* one per active hook */
69 u_int flags;
70#define CHAN_VALID 0x01 /* assigned to a channel */
71#define CHAN_ACTIVE 0x02 /* bottom level active */
72 int dlci; /* the dlci assigned to this context */
73 hook_p hook; /* if there's a hook assigned.. */
74};
75
76#define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */
77struct frmrel_softc {
78 int unit; /* which card are we? */
79 int datahooks; /* number of data hooks attached */
80 node_p node; /* netgraph node */
81 int addrlen; /* address header length */
82 int flags; /* state */
83 int mtu; /* guess */
84 u_char remote_seq; /* sequence number the remote sent */
85 u_char local_seq; /* sequence number the remote rcvd */
86 u_short ALT[1024]; /* map DLCIs to CTX */
87#define CTX_VALID 0x8000 /* this bit means it's a valid CTX */
88#define CTX_VALUE (MAX_CT - 1) /* mask for context part */
89 struct ctxinfo channel[MAX_CT];
90 struct ctxinfo downstream;
91};
92typedef struct frmrel_softc *sc_p;
93
94#define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */
95#define BYTE1_C_R 0x02
96#define BYTE2_FECN 0x08 /* forwards congestion notification */
97#define BYTE2_BECN 0x04 /* Backward congestion notification */
98#define BYTE2_DE 0x02 /* Discard elligability */
99#define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */
100
101/* Used to do headers */
102static struct segment {
103 u_char mask;
104 u_char shift;
105 u_char width;
106} makeup[] = {
107 { 0xfc, 2, 6 },
108 { 0xf0, 4, 4 },
109 { 0xfe, 1, 7 },
110 { 0xfc, 2, 6 }
111};
112
113#define SHIFTIN(segment, byte, dlci) \
114 { \
115 (dlci) <<= (segment)->width; \
116 (dlci) |= \
117 (((byte) & (segment)->mask) >> (segment)->shift); \
118 }
119
120#define SHIFTOUT(segment, byte, dlci) \
121 { \
122 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \
123 (dlci) >>= (segment)->width; \
124 }
125
126/* Netgraph methods */
127static ng_constructor_t ngfrm_constructor;
128static ng_shutdown_t ngfrm_rmnode;
129static ng_newhook_t ngfrm_newhook;
130static ng_rcvdata_t ngfrm_rcvdata;
131static ng_disconnect_t ngfrm_disconnect;
132
133/* Other internal functions */
134static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta);
135static int ngfrm_addrlen(char *hdr);
136static int ngfrm_allocate_CTX(sc_p sc, int dlci);
137
138/* Netgraph type */
139static struct ng_type typestruct = {
140 NG_VERSION,
141 NG_FRAMERELAY_NODE_TYPE,
142 NULL,
143 ngfrm_constructor,
144 NULL,
145 ngfrm_rmnode,
146 ngfrm_newhook,
147 NULL,
148 NULL,
149 ngfrm_rcvdata,
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150 ngfrm_rcvdata,
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150 ngfrm_disconnect,
151 NULL
152};
153NETGRAPH_INIT(framerelay, &typestruct);
154
155/*
156 * Given a DLCI, return the index of the context table entry for it,
157 * Allocating a new one if needs be, or -1 if none available.
158 */
159static int
160ngfrm_allocate_CTX(sc_p sc, int dlci)
161{
162 u_int ctxnum = -1; /* what ctx number we are using */
163 volatile struct ctxinfo *CTXp = NULL;
164
165 /* Sanity check the dlci value */
166 if (dlci > 1023)
167 return (-1);
168
169 /* Check to see if we already have an entry for this DLCI */
170 if (sc->ALT[dlci]) {
171 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
172 CTXp = sc->channel + ctxnum;
173 } else {
174 ctxnum = -1;
175 sc->ALT[dlci] = 0; /* paranoid but... */
176 }
177 }
178
179 /*
180 * If the index has no valid entry yet, then we need to allocate a
181 * CTX number to it
182 */
183 if (CTXp == NULL) {
184 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
185 /*
186 * If the VALID flag is empty it is unused
187 */
188 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
189 bzero(sc->channel + ctxnum,
190 sizeof(struct ctxinfo));
191 CTXp = sc->channel + ctxnum;
192 sc->ALT[dlci] = ctxnum | CTX_VALID;
193 sc->channel[ctxnum].dlci = dlci;
194 sc->channel[ctxnum].flags = CHAN_VALID;
195 break;
196 }
197 }
198 }
199
200 /*
201 * If we still don't have a CTX pointer, then we never found a free
202 * spot so give up now..
203 */
204 if (!CTXp) {
205 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
206 return (-1);
207 }
208 return (ctxnum);
209}
210
211/*
212 * Node constructor
213 */
214static int
215ngfrm_constructor(node_p *nodep)
216{
217 sc_p sc;
218 int error = 0;
219
220 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
221 if (!sc)
222 return (ENOMEM);
223 if ((error = ng_make_node_common(&typestruct, nodep))) {
224 FREE(sc, M_NETGRAPH);
225 return (error);
226 }
227 sc->addrlen = 2; /* default */
228
229 /* Link the node and our private info */
230 (*nodep)->private = sc;
231 sc->node = *nodep;
232 return (0);
233}
234
235/*
236 * Add a new hook
237 *
238 * We allow hooks called "debug", "downstream" and dlci[0-1023]
239 * The hook's private info points to our stash of info about that
240 * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
241 */
242static int
243ngfrm_newhook(node_p node, hook_p hook, const char *name)
244{
245 const sc_p sc = node->private;
246 const char *cp;
247 char *eptr;
248 int dlci = 0;
249 int ctxnum;
250
251 /* Check if it's our friend the control hook */
252 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
253 hook->private = NULL; /* paranoid */
254 return (0);
255 }
256
257 /*
258 * All other hooks either start with 'dlci' and have a decimal
259 * trailing channel number up to 4 digits, or are the downstream
260 * hook.
261 */
262 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
263 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
264
265 /* It must be the downstream connection */
266 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
267 return EINVAL;
268
269 /* Make sure we haven't already got one (paranoid) */
270 if (sc->downstream.hook)
271 return (EADDRINUSE);
272
273 /* OK add it */
274 hook->private = &sc->downstream;
275 sc->downstream.hook = hook;
276 sc->downstream.dlci = -1;
277 sc->downstream.flags |= CHAN_ACTIVE;
278 sc->datahooks++;
279 return (0);
280 }
281
282 /* Must be a dlci hook at this point */
283 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
284 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
285 return (EINVAL);
286 dlci = (int)strtoul(cp, &eptr, 10);
287 if (*eptr != '\0' || dlci < 0 || dlci > 1023)
288 return (EINVAL);
289
290 /*
291 * We have a dlci, now either find it, or allocate it. It's possible
292 * that we might have seen packets for it already and made an entry
293 * for it.
294 */
295 ctxnum = ngfrm_allocate_CTX(sc, dlci);
296 if (ctxnum == -1)
297 return (ENOBUFS);
298
299 /*
300 * Be paranoid: if it's got a hook already, that dlci is in use .
301 * Generic code can not catch all the synonyms (e.g. dlci016 vs
302 * dlci16)
303 */
304 if (sc->channel[ctxnum].hook != NULL)
305 return (EADDRINUSE);
306
307 /*
308 * Put our hooks into it (pun not intended)
309 */
310 sc->channel[ctxnum].flags |= CHAN_ACTIVE;
311 hook->private = sc->channel + ctxnum;
312 sc->channel[ctxnum].hook = hook;
313 sc->datahooks++;
314 return (0);
315}
316
317/*
318 * Count up the size of the address header if we don't already know
319 */
320int
321ngfrm_addrlen(char *hdr)
322{
323 if (hdr[0] & BYTEX_EA)
324 return 0;
325 if (hdr[1] & BYTEX_EA)
326 return 2;
327 if (hdr[2] & BYTEX_EA)
328 return 3;
329 if (hdr[3] & BYTEX_EA)
330 return 4;
331 return 0;
332}
333
334/*
335 * Receive data packet
336 */
337static int
338ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
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340 struct mbuf **ret_m, meta_p *ret_meta)
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| 339 struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp) |
340{
341 struct ctxinfo *const ctxp = hook->private;
342 int error = 0;
343 int dlci;
344 sc_p sc;
345 int alen;
346 char *data;
347
348 /* Data doesn't come in from just anywhere (e.g debug hook) */
349 if (ctxp == NULL) {
350 error = ENETDOWN;
351 goto bad;
352 }
353
354 /* If coming from downstream, decode it to a channel */
355 dlci = ctxp->dlci;
356 if (dlci == -1)
357 return (ngfrm_decode(hook->node, m, meta));
358
359 /* Derive the softc we will need */
360 sc = hook->node->private;
361
362 /* If there is no live channel, throw it away */
363 if ((sc->downstream.hook == NULL)
364 || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
365 error = ENETDOWN;
366 goto bad;
367 }
368
369 /* Store the DLCI on the front of the packet */
370 alen = sc->addrlen;
371 if (alen == 0)
372 alen = 2; /* default value for transmit */
373 M_PREPEND(m, alen, M_DONTWAIT);
374 if (m == NULL) {
375 error = ENOBUFS;
376 goto bad;
377 }
378 data = mtod(m, char *);
379
380 /*
381 * Shift the lowest bits into the address field untill we are done.
382 * First byte is MSBits of addr so work backwards.
383 */
384 switch (alen) {
385 case 2:
386 data[0] = data[1] = '\0';
387 SHIFTOUT(makeup + 1, data[1], dlci);
388 SHIFTOUT(makeup + 0, data[0], dlci);
389 data[1] |= BYTEX_EA;
390 break;
391 case 3:
392 data[0] = data[1] = data[2] = '\0';
393 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
394 SHIFTOUT(makeup + 1, data[1], dlci);
395 SHIFTOUT(makeup + 0, data[0], dlci);
396 data[2] |= BYTEX_EA;
397 break;
398 case 4:
399 data[0] = data[1] = data[2] = data[3] = '\0';
400 SHIFTOUT(makeup + 3, data[3], dlci);
401 SHIFTOUT(makeup + 2, data[2], dlci);
402 SHIFTOUT(makeup + 1, data[1], dlci);
403 SHIFTOUT(makeup + 0, data[0], dlci);
404 data[3] |= BYTEX_EA;
405 break;
406 default:
407 panic(__FUNCTION__);
408 }
409
410 /* Send it */
411 NG_SEND_DATA(error, sc->downstream.hook, m, meta);
412 return (error);
413
414bad:
415 NG_FREE_DATA(m, meta);
416 return (error);
417}
418
419/*
420 * Decode an incoming frame coming from the switch
421 */
422static int
423ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
424{
425 const sc_p sc = node->private;
426 char *data;
427 int alen;
428 u_int dlci = 0;
429 int error = 0;
430 int ctxnum;
431
432 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
433 error = ENOBUFS;
434 goto out;
435 }
436 data = mtod(m, char *);
437 if ((alen = sc->addrlen) == 0) {
438 sc->addrlen = alen = ngfrm_addrlen(data);
439 }
440 switch (alen) {
441 case 2:
442 SHIFTIN(makeup + 0, data[0], dlci);
443 SHIFTIN(makeup + 1, data[1], dlci);
444 break;
445 case 3:
446 SHIFTIN(makeup + 0, data[0], dlci);
447 SHIFTIN(makeup + 1, data[1], dlci);
448 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
449 break;
450 case 4:
451 SHIFTIN(makeup + 0, data[0], dlci);
452 SHIFTIN(makeup + 1, data[1], dlci);
453 SHIFTIN(makeup + 2, data[2], dlci);
454 SHIFTIN(makeup + 3, data[3], dlci);
455 break;
456 default:
457 error = EINVAL;
458 goto out;
459 }
460
461 if (dlci > 1023) {
462 error = EINVAL;
463 goto out;
464 }
465 ctxnum = sc->ALT[dlci];
466 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
467 /* Send it */
468 m_adj(m, alen);
469 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
470 return (error);
471 } else {
472 error = ENETDOWN;
473 }
474out:
475 NG_FREE_DATA(m, meta);
476 return (error);
477}
478
479/*
480 * Shutdown node
481 */
482static int
483ngfrm_rmnode(node_p node)
484{
485 const sc_p sc = node->private;
486
487 node->flags |= NG_INVALID;
488 ng_cutlinks(node);
489 ng_unname(node);
490 node->private = NULL;
491 FREE(sc, M_NETGRAPH);
492 ng_unref(node);
493 return (0);
494}
495
496/*
497 * Hook disconnection
498 *
499 * Invalidate the private data associated with this dlci.
500 * For this type, removal of the last link resets tries to destroy the node.
501 */
502static int
503ngfrm_disconnect(hook_p hook)
504{
505 const sc_p sc = hook->node->private;
506 struct ctxinfo *const cp = hook->private;
507 int dlci;
508
509 /* If it's a regular dlci hook, then free resources etc.. */
510 if (cp != NULL) {
511 cp->hook = NULL;
512 dlci = cp->dlci;
513 if (dlci != -1)
514 sc->ALT[dlci] = 0;
515 cp->flags = 0;
516 sc->datahooks--;
517 }
518 if (hook->node->numhooks == 0)
519 ng_rmnode(hook->node);
520 return (0);
521}
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