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 Elischer <julian@freebsd.org>
38 *
39 * $FreeBSD: releng/5.3/sys/netgraph/ng_frame_relay.c 136588 2004-10-16 08:43:07Z cvs2svn $
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 */
68 struct 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!) */
77 struct 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 };
92 typedef 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 */
102 const static 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 */
127 static ng_constructor_t ngfrm_constructor;
128 static ng_shutdown_t ngfrm_shutdown;
129 static ng_newhook_t ngfrm_newhook;
130 static ng_rcvdata_t ngfrm_rcvdata;
131 static ng_disconnect_t ngfrm_disconnect;
132
133 /* Other internal functions */
134 static int ngfrm_decode(node_p node, item_p item);
135 static int ngfrm_addrlen(char *hdr);
136 static int ngfrm_allocate_CTX(sc_p sc, int dlci);
137
138 /* Netgraph type */
139 static struct ng_type typestruct = {
140 .version = NG_ABI_VERSION,
141 .name = NG_FRAMERELAY_NODE_TYPE,
142 .constructor = ngfrm_constructor,
143 .shutdown = ngfrm_shutdown,
144 .newhook = ngfrm_newhook,
145 .rcvdata = ngfrm_rcvdata,
146 .disconnect = ngfrm_disconnect,
147 };
148 NETGRAPH_INIT(framerelay, &typestruct);
149
150 /*
151 * Given a DLCI, return the index of the context table entry for it,
152 * Allocating a new one if needs be, or -1 if none available.
153 */
154 static int
155 ngfrm_allocate_CTX(sc_p sc, int dlci)
156 {
157 u_int ctxnum = -1; /* what ctx number we are using */
158 volatile struct ctxinfo *CTXp = NULL;
159
160 /* Sanity check the dlci value */
161 if (dlci > 1023)
162 return (-1);
163
164 /* Check to see if we already have an entry for this DLCI */
165 if (sc->ALT[dlci]) {
166 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
167 CTXp = sc->channel + ctxnum;
168 } else {
169 ctxnum = -1;
170 sc->ALT[dlci] = 0; /* paranoid but... */
171 }
172 }
173
174 /*
175 * If the index has no valid entry yet, then we need to allocate a
176 * CTX number to it
177 */
178 if (CTXp == NULL) {
179 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
180 /*
181 * If the VALID flag is empty it is unused
182 */
183 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
184 bzero(sc->channel + ctxnum,
185 sizeof(struct ctxinfo));
186 CTXp = sc->channel + ctxnum;
187 sc->ALT[dlci] = ctxnum | CTX_VALID;
188 sc->channel[ctxnum].dlci = dlci;
189 sc->channel[ctxnum].flags = CHAN_VALID;
190 break;
191 }
192 }
193 }
194
195 /*
196 * If we still don't have a CTX pointer, then we never found a free
197 * spot so give up now..
198 */
199 if (!CTXp) {
200 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
201 return (-1);
202 }
203 return (ctxnum);
204 }
205
206 /*
207 * Node constructor
208 */
209 static int
210 ngfrm_constructor(node_p node)
211 {
212 sc_p sc;
213
214 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
215 if (!sc)
216 return (ENOMEM);
217 sc->addrlen = 2; /* default */
218
219 /* Link the node and our private info */
220 NG_NODE_SET_PRIVATE(node, sc);
221 sc->node = node;
222 return (0);
223 }
224
225 /*
226 * Add a new hook
227 *
228 * We allow hooks called "debug", "downstream" and dlci[0-1023]
229 * The hook's private info points to our stash of info about that
230 * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
231 */
232 static int
233 ngfrm_newhook(node_p node, hook_p hook, const char *name)
234 {
235 const sc_p sc = NG_NODE_PRIVATE(node);
236 const char *cp;
237 char *eptr;
238 int dlci = 0;
239 int ctxnum;
240
241 /* Check if it's our friend the control hook */
242 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
243 NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */
244 return (0);
245 }
246
247 /*
248 * All other hooks either start with 'dlci' and have a decimal
249 * trailing channel number up to 4 digits, or are the downstream
250 * hook.
251 */
252 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
253 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
254
255 /* It must be the downstream connection */
256 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
257 return EINVAL;
258
259 /* Make sure we haven't already got one (paranoid) */
260 if (sc->downstream.hook)
261 return (EADDRINUSE);
262
263 /* OK add it */
264 NG_HOOK_SET_PRIVATE(hook, &sc->downstream);
265 sc->downstream.hook = hook;
266 sc->downstream.dlci = -1;
267 sc->downstream.flags |= CHAN_ACTIVE;
268 sc->datahooks++;
269 return (0);
270 }
271
272 /* Must be a dlci hook at this point */
273 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
274 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0'))
275 return (EINVAL);
276 dlci = (int)strtoul(cp, &eptr, 10);
277 if (*eptr != '\0' || dlci < 0 || dlci > 1023)
278 return (EINVAL);
279
280 /*
281 * We have a dlci, now either find it, or allocate it. It's possible
282 * that we might have seen packets for it already and made an entry
283 * for it.
284 */
285 ctxnum = ngfrm_allocate_CTX(sc, dlci);
286 if (ctxnum == -1)
287 return (ENOBUFS);
288
289 /*
290 * Be paranoid: if it's got a hook already, that dlci is in use .
291 * Generic code can not catch all the synonyms (e.g. dlci016 vs
292 * dlci16)
293 */
294 if (sc->channel[ctxnum].hook != NULL)
295 return (EADDRINUSE);
296
297 /*
298 * Put our hooks into it (pun not intended)
299 */
300 sc->channel[ctxnum].flags |= CHAN_ACTIVE;
301 NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum);
302 sc->channel[ctxnum].hook = hook;
303 sc->datahooks++;
304 return (0);
305 }
306
307 /*
308 * Count up the size of the address header if we don't already know
309 */
310 int
311 ngfrm_addrlen(char *hdr)
312 {
313 if (hdr[0] & BYTEX_EA)
314 return 0;
315 if (hdr[1] & BYTEX_EA)
316 return 2;
317 if (hdr[2] & BYTEX_EA)
318 return 3;
319 if (hdr[3] & BYTEX_EA)
320 return 4;
321 return 0;
322 }
323
324 /*
325 * Receive data packet
326 */
327 static int
328 ngfrm_rcvdata(hook_p hook, item_p item)
329 {
330 struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook);
331 int error = 0;
332 int dlci;
333 sc_p sc;
334 int alen;
335 char *data;
336 struct mbuf *m;
337
338 /* Data doesn't come in from just anywhere (e.g debug hook) */
339 if (ctxp == NULL) {
340 error = ENETDOWN;
341 goto bad;
342 }
343
344 /* If coming from downstream, decode it to a channel */
345 dlci = ctxp->dlci;
346 if (dlci == -1)
347 return (ngfrm_decode(NG_HOOK_NODE(hook), item));
348
349 NGI_GET_M(item, m);
350 /* Derive the softc we will need */
351 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
352
353 /* If there is no live channel, throw it away */
354 if ((sc->downstream.hook == NULL)
355 || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
356 error = ENETDOWN;
357 goto bad;
358 }
359
360 /* Store the DLCI on the front of the packet */
361 alen = sc->addrlen;
362 if (alen == 0)
363 alen = 2; /* default value for transmit */
364 M_PREPEND(m, alen, M_DONTWAIT);
365 if (m == NULL) {
366 error = ENOBUFS;
367 goto bad;
368 }
369 data = mtod(m, char *);
370
371 /*
372 * Shift the lowest bits into the address field untill we are done.
373 * First byte is MSBits of addr so work backwards.
374 */
375 switch (alen) {
376 case 2:
377 data[0] = data[1] = '\0';
378 SHIFTOUT(makeup + 1, data[1], dlci);
379 SHIFTOUT(makeup + 0, data[0], dlci);
380 data[1] |= BYTEX_EA;
381 break;
382 case 3:
383 data[0] = data[1] = data[2] = '\0';
384 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
385 SHIFTOUT(makeup + 1, data[1], dlci);
386 SHIFTOUT(makeup + 0, data[0], dlci);
387 data[2] |= BYTEX_EA;
388 break;
389 case 4:
390 data[0] = data[1] = data[2] = data[3] = '\0';
391 SHIFTOUT(makeup + 3, data[3], dlci);
392 SHIFTOUT(makeup + 2, data[2], dlci);
393 SHIFTOUT(makeup + 1, data[1], dlci);
394 SHIFTOUT(makeup + 0, data[0], dlci);
395 data[3] |= BYTEX_EA;
396 break;
397 default:
398 panic(__func__);
399 }
400
401 /* Send it */
402 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m);
403 return (error);
404
405 bad:
406 NG_FREE_ITEM(item);
407 NG_FREE_M(m);
408 return (error);
409 }
410
411 /*
412 * Decode an incoming frame coming from the switch
413 */
414 static int
415 ngfrm_decode(node_p node, item_p item)
416 {
417 const sc_p sc = NG_NODE_PRIVATE(node);
418 char *data;
419 int alen;
420 u_int dlci = 0;
421 int error = 0;
422 int ctxnum;
423 struct mbuf *m;
424
425 NGI_GET_M(item, m);
426 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
427 error = ENOBUFS;
428 goto out;
429 }
430 data = mtod(m, char *);
431 if ((alen = sc->addrlen) == 0) {
432 sc->addrlen = alen = ngfrm_addrlen(data);
433 }
434 switch (alen) {
435 case 2:
436 SHIFTIN(makeup + 0, data[0], dlci);
437 SHIFTIN(makeup + 1, data[1], dlci);
438 break;
439 case 3:
440 SHIFTIN(makeup + 0, data[0], dlci);
441 SHIFTIN(makeup + 1, data[1], dlci);
442 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
443 break;
444 case 4:
445 SHIFTIN(makeup + 0, data[0], dlci);
446 SHIFTIN(makeup + 1, data[1], dlci);
447 SHIFTIN(makeup + 2, data[2], dlci);
448 SHIFTIN(makeup + 3, data[3], dlci);
449 break;
450 default:
451 error = EINVAL;
452 goto out;
453 }
454
455 if (dlci > 1023) {
456 error = EINVAL;
457 goto out;
458 }
459 ctxnum = sc->ALT[dlci];
460 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
461 /* Send it */
462 m_adj(m, alen);
463 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m);
464 return (error);
465 } else {
466 error = ENETDOWN;
467 }
468 out:
469 NG_FREE_ITEM(item);
470 NG_FREE_M(m);
471 return (error);
472 }
473
474 /*
475 * Shutdown node
476 */
477 static int
478 ngfrm_shutdown(node_p node)
479 {
480 const sc_p sc = NG_NODE_PRIVATE(node);
481
482 NG_NODE_SET_PRIVATE(node, NULL);
483 FREE(sc, M_NETGRAPH);
484 NG_NODE_UNREF(node);
485 return (0);
486 }
487
488 /*
489 * Hook disconnection
490 *
491 * Invalidate the private data associated with this dlci.
492 * For this type, removal of the last link resets tries to destroy the node.
493 */
494 static int
495 ngfrm_disconnect(hook_p hook)
496 {
497 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
498 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook);
499 int dlci;
500
501 /* If it's a regular dlci hook, then free resources etc.. */
502 if (cp != NULL) {
503 cp->hook = NULL;
504 dlci = cp->dlci;
505 if (dlci != -1)
506 sc->ALT[dlci] = 0;
507 cp->flags = 0;
508 sc->datahooks--;
509 }
510 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
511 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
512 ng_rmnode_self(NG_HOOK_NODE(hook));
513 return (0);
514 }
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