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 * $FreeBSD$
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 #include <machine/clock.h>
61
62 #include <netgraph/ng_message.h>
63 #include <netgraph/netgraph.h>
64 #include <netgraph/ng_frame_relay.h>
65
66 /*
67 * Line info, and status per channel.
68 */
69 struct ctxinfo { /* one per active hook */
70 u_int flags;
71 #define CHAN_VALID 0x01 /* assigned to a channel */
72 #define CHAN_ACTIVE 0x02 /* bottom level active */
73 int dlci; /* the dlci assigned to this context */
74 hook_p hook; /* if there's a hook assigned.. */
75 };
76
77 #define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */
78 struct frmrel_softc {
79 int unit; /* which card are we? */
80 int datahooks; /* number of data hooks attached */
81 node_p node; /* netgraph node */
82 int addrlen; /* address header length */
83 int flags; /* state */
84 int mtu; /* guess */
85 u_char remote_seq; /* sequence number the remote sent */
86 u_char local_seq; /* sequence number the remote rcvd */
87 u_short ALT[1024]; /* map DLCIs to CTX */
88 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */
89 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */
90 struct ctxinfo channel[MAX_CT];
91 struct ctxinfo downstream;
92 };
93 typedef struct frmrel_softc *sc_p;
94
95 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */
96 #define BYTE1_C_R 0x02
97 #define BYTE2_FECN 0x08 /* forwards congestion notification */
98 #define BYTE2_BECN 0x04 /* Backward congestion notification */
99 #define BYTE2_DE 0x02 /* Discard elligability */
100 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */
101
102 /* Used to do headers */
103 static struct segment {
104 u_char mask;
105 u_char shift;
106 u_char width;
107 } makeup[] = {
108 { 0xfc, 2, 6 },
109 { 0xf0, 4, 4 },
110 { 0xfe, 1, 7 },
111 { 0xfc, 2, 6 }
112 };
113
114 #define SHIFTIN(segment, byte, dlci) \
115 { \
116 (dlci) <<= (segment)->width; \
117 (dlci) |= \
118 (((byte) & (segment)->mask) >> (segment)->shift); \
119 }
120
121 #define SHIFTOUT(segment, byte, dlci) \
122 { \
123 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \
124 (dlci) >>= (segment)->width; \
125 }
126
127 /* Netgraph methods */
128 static ng_constructor_t ngfrm_constructor;
129 static ng_shutdown_t ngfrm_rmnode;
130 static ng_newhook_t ngfrm_newhook;
131 static ng_rcvdata_t ngfrm_rcvdata;
132 static ng_disconnect_t ngfrm_disconnect;
133
134 /* Other internal functions */
135 static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta);
136 static int ngfrm_addrlen(char *hdr);
137 static int ngfrm_allocate_CTX(sc_p sc, int dlci);
138
139 /* Netgraph type */
140 static struct ng_type typestruct = {
141 NG_VERSION,
142 NG_FRAMERELAY_NODE_TYPE,
143 NULL,
144 ngfrm_constructor,
145 NULL,
146 ngfrm_rmnode,
147 ngfrm_newhook,
148 NULL,
149 NULL,
150 ngfrm_rcvdata,
151 ngfrm_rcvdata,
152 ngfrm_disconnect,
153 NULL
154 };
155 NETGRAPH_INIT(framerelay, &typestruct);
156
157 /*
158 * Given a DLCI, return the index of the context table entry for it,
159 * Allocating a new one if needs be, or -1 if none available.
160 */
161 static int
162 ngfrm_allocate_CTX(sc_p sc, int dlci)
163 {
164 u_int ctxnum = -1; /* what ctx number we are using */
165 volatile struct ctxinfo *CTXp = NULL;
166
167 /* Sanity check the dlci value */
168 if (dlci > 1023)
169 return (-1);
170
171 /* Check to see if we already have an entry for this DLCI */
172 if (sc->ALT[dlci]) {
173 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
174 CTXp = sc->channel + ctxnum;
175 } else {
176 ctxnum = -1;
177 sc->ALT[dlci] = 0; /* paranoid but... */
178 }
179 }
180
181 /*
182 * If the index has no valid entry yet, then we need to allocate a
183 * CTX number to it
184 */
185 if (CTXp == NULL) {
186 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
187 /*
188 * If the VALID flag is empty it is unused
189 */
190 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
191 bzero(sc->channel + ctxnum,
192 sizeof(struct ctxinfo));
193 CTXp = sc->channel + ctxnum;
194 sc->ALT[dlci] = ctxnum | CTX_VALID;
195 sc->channel[ctxnum].dlci = dlci;
196 sc->channel[ctxnum].flags = CHAN_VALID;
197 break;
198 }
199 }
200 }
201
202 /*
203 * If we still don't have a CTX pointer, then we never found a free
204 * spot so give up now..
205 */
206 if (!CTXp) {
207 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
208 return (-1);
209 }
210 return (ctxnum);
211 }
212
213 /*
214 * Node constructor
215 */
216 static int
217 ngfrm_constructor(node_p *nodep)
218 {
219 sc_p sc;
220 int error = 0;
221
222 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT);
223 if (!sc)
224 return (ENOMEM);
225 bzero(sc, sizeof(*sc));
226 if ((error = ng_make_node_common(&typestruct, nodep))) {
227 FREE(sc, M_NETGRAPH);
228 return (error);
229 }
230 sc->addrlen = 2; /* default */
231
232 /* Link the node and our private info */
233 (*nodep)->private = sc;
234 sc->node = *nodep;
235 return (0);
236 }
237
238 /*
239 * Add a new hook
240 *
241 * We allow hooks called "debug", "downstream" and dlci[0-1023]
242 * The hook's private info points to our stash of info about that
243 * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
244 */
245 static int
246 ngfrm_newhook(node_p node, hook_p hook, const char *name)
247 {
248 const sc_p sc = node->private;
249 const char *cp;
250 char *eptr;
251 int dlci = 0;
252 int ctxnum;
253
254 /* Check if it's our friend the control hook */
255 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
256 hook->private = NULL; /* paranoid */
257 return (0);
258 }
259
260 /*
261 * All other hooks either start with 'dlci' and have a decimal
262 * trailing channel number up to 4 digits, or are the downstream
263 * hook.
264 */
265 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
266 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
267
268 /* It must be the downstream connection */
269 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
270 return EINVAL;
271
272 /* Make sure we haven't already got one (paranoid) */
273 if (sc->downstream.hook)
274 return (EADDRINUSE);
275
276 /* OK add it */
277 hook->private = &sc->downstream;
278 sc->downstream.hook = hook;
279 sc->downstream.dlci = -1;
280 sc->downstream.flags |= CHAN_ACTIVE;
281 sc->datahooks++;
282 return (0);
283 }
284
285 /* Must be a dlci hook at this point */
286 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
287 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0'))
288 return (EINVAL);
289 dlci = (int)strtoul(cp, &eptr, 10);
290 if (*eptr != '\0' || dlci < 0 || dlci > 1023)
291 return (EINVAL);
292
293 /*
294 * We have a dlci, now either find it, or allocate it. It's possible
295 * that we might have seen packets for it already and made an entry
296 * for it.
297 */
298 ctxnum = ngfrm_allocate_CTX(sc, dlci);
299 if (ctxnum == -1)
300 return (ENOBUFS);
301
302 /*
303 * Be paranoid: if it's got a hook already, that dlci is in use .
304 * Generic code can not catch all the synonyms (e.g. dlci016 vs
305 * dlci16)
306 */
307 if (sc->channel[ctxnum].hook != NULL)
308 return (EADDRINUSE);
309
310 /*
311 * Put our hooks into it (pun not intended)
312 */
313 sc->channel[ctxnum].flags |= CHAN_ACTIVE;
314 hook->private = sc->channel + ctxnum;
315 sc->channel[ctxnum].hook = hook;
316 sc->datahooks++;
317 return (0);
318 }
319
320 /*
321 * Count up the size of the address header if we don't already know
322 */
323 int
324 ngfrm_addrlen(char *hdr)
325 {
326 if (hdr[0] & BYTEX_EA)
327 return 0;
328 if (hdr[1] & BYTEX_EA)
329 return 2;
330 if (hdr[2] & BYTEX_EA)
331 return 3;
332 if (hdr[3] & BYTEX_EA)
333 return 4;
334 return 0;
335 }
336
337 /*
338 * Receive data packet
339 */
340 static int
341 ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
342 {
343 struct ctxinfo *const ctxp = hook->private;
344 int error = 0;
345 int dlci;
346 sc_p sc;
347 int alen;
348 char *data;
349
350 /* Data doesn't come in from just anywhere (e.g debug hook) */
351 if (ctxp == NULL) {
352 error = ENETDOWN;
353 goto bad;
354 }
355
356 /* If coming from downstream, decode it to a channel */
357 dlci = ctxp->dlci;
358 if (dlci == -1)
359 return (ngfrm_decode(hook->node, m, meta));
360
361 /* Derive the softc we will need */
362 sc = hook->node->private;
363
364 /* If there is no live channel, throw it away */
365 if ((sc->downstream.hook == NULL)
366 || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
367 error = ENETDOWN;
368 goto bad;
369 }
370
371 /* Store the DLCI on the front of the packet */
372 alen = sc->addrlen;
373 if (alen == 0)
374 alen = 2; /* default value for transmit */
375 M_PREPEND(m, alen, M_DONTWAIT);
376 if (m == NULL) {
377 error = ENOBUFS;
378 goto bad;
379 }
380 data = mtod(m, char *);
381
382 /*
383 * Shift the lowest bits into the address field untill we are done.
384 * First byte is MSBits of addr so work backwards.
385 */
386 switch (alen) {
387 case 2:
388 data[0] = data[1] = '\0';
389 SHIFTOUT(makeup + 1, data[1], dlci);
390 SHIFTOUT(makeup + 0, data[0], dlci);
391 data[1] |= BYTEX_EA;
392 break;
393 case 3:
394 data[0] = data[1] = data[2] = '\0';
395 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
396 SHIFTOUT(makeup + 1, data[1], dlci);
397 SHIFTOUT(makeup + 0, data[0], dlci);
398 data[2] |= BYTEX_EA;
399 break;
400 case 4:
401 data[0] = data[1] = data[2] = data[3] = '\0';
402 SHIFTOUT(makeup + 3, data[3], dlci);
403 SHIFTOUT(makeup + 2, data[2], dlci);
404 SHIFTOUT(makeup + 1, data[1], dlci);
405 SHIFTOUT(makeup + 0, data[0], dlci);
406 data[3] |= BYTEX_EA;
407 break;
408 default:
409 panic(__FUNCTION__);
410 }
411
412 /* Send it */
413 NG_SEND_DATA(error, sc->downstream.hook, m, meta);
414 return (error);
415
416 bad:
417 NG_FREE_DATA(m, meta);
418 return (error);
419 }
420
421 /*
422 * Decode an incoming frame coming from the switch
423 */
424 static int
425 ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
426 {
427 const sc_p sc = node->private;
428 char *data;
429 int alen;
430 u_int dlci = 0;
431 int error = 0;
432 int ctxnum;
433
434 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
435 error = ENOBUFS;
436 goto out;
437 }
438 data = mtod(m, char *);
439 if ((alen = sc->addrlen) == 0) {
440 sc->addrlen = alen = ngfrm_addrlen(data);
441 }
442 switch (alen) {
443 case 2:
444 SHIFTIN(makeup + 0, data[0], dlci);
445 SHIFTIN(makeup + 1, data[1], dlci);
446 break;
447 case 3:
448 SHIFTIN(makeup + 0, data[0], dlci);
449 SHIFTIN(makeup + 1, data[1], dlci);
450 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
451 break;
452 case 4:
453 SHIFTIN(makeup + 0, data[0], dlci);
454 SHIFTIN(makeup + 1, data[1], dlci);
455 SHIFTIN(makeup + 2, data[2], dlci);
456 SHIFTIN(makeup + 3, data[3], dlci);
457 break;
458 default:
459 error = EINVAL;
460 goto out;
461 }
462
463 if (dlci > 1023) {
464 error = EINVAL;
465 goto out;
466 }
467 ctxnum = sc->ALT[dlci];
468 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
469 /* Send it */
470 m_adj(m, alen);
471 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
472 return (error);
473 } else {
474 error = ENETDOWN;
475 }
476 out:
477 NG_FREE_DATA(m, meta);
478 return (error);
479 }
480
481 /*
482 * Shutdown node
483 */
484 static int
485 ngfrm_rmnode(node_p node)
486 {
487 const sc_p sc = node->private;
488
489 node->flags |= NG_INVALID;
490 ng_cutlinks(node);
491 ng_unname(node);
492 node->private = NULL;
493 FREE(sc, M_NETGRAPH);
494 ng_unref(sc->node);
495 return (0);
496 }
497
498 /*
499 * Hook disconnection
500 *
501 * Invalidate the private data associated with this dlci.
502 * For this type, removal of the last link resets tries to destroy the node.
503 */
504 static int
505 ngfrm_disconnect(hook_p hook)
506 {
507 const sc_p sc = hook->node->private;
508 struct ctxinfo *const cp = hook->private;
509 int dlci;
510
511 /* If it's a regular dlci hook, then free resources etc.. */
512 if (cp != NULL) {
513 cp->hook = NULL;
514 dlci = cp->dlci;
515 if (dlci != -1)
516 sc->ALT[dlci] = 0;
517 cp->flags = 0;
518 sc->datahooks--;
519 }
520 if (hook->node->numhooks == 0)
521 ng_rmnode(hook->node);
522 return (0);
523 }
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