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