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 * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
40 */
41
42 /*
43 * This node implements the frame relay protocol, not including
44 * the LMI line management. This means basically keeping track
45 * of which DLCI's are active, doing frame (de)multiplexing, etc.
46 *
47 * It has a 'downstream' hook that goes to the line, and a
48 * hook for each DLCI (eg, 'dlci16').
49 */
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/kernel.h>
54 #include <sys/errno.h>
55 #include <sys/malloc.h>
56 #include <sys/mbuf.h>
57 #include <sys/syslog.h>
58 #include <sys/ctype.h>
59
60 #include <netgraph/ng_message.h>
61 #include <netgraph/netgraph.h>
62 #include <netgraph/ng_frame_relay.h>
63
64 /*
65 * Line info, and status per channel.
66 */
67 struct ctxinfo { /* one per active hook */
68 u_int flags;
69 #define CHAN_VALID 0x01 /* assigned to a channel */
70 #define CHAN_ACTIVE 0x02 /* bottom level active */
71 int dlci; /* the dlci assigned to this context */
72 hook_p hook; /* if there's a hook assigned.. */
73 };
74
75 #define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */
76 struct frmrel_softc {
77 int unit; /* which card are we? */
78 int datahooks; /* number of data hooks attached */
79 node_p node; /* netgraph node */
80 int addrlen; /* address header length */
81 int flags; /* state */
82 int mtu; /* guess */
83 u_char remote_seq; /* sequence number the remote sent */
84 u_char local_seq; /* sequence number the remote rcvd */
85 u_short ALT[1024]; /* map DLCIs to CTX */
86 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */
87 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */
88 struct ctxinfo channel[MAX_CT];
89 struct ctxinfo downstream;
90 };
91 typedef struct frmrel_softc *sc_p;
92
93 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */
94 #define BYTE1_C_R 0x02
95 #define BYTE2_FECN 0x08 /* forwards congestion notification */
96 #define BYTE2_BECN 0x04 /* Backward congestion notification */
97 #define BYTE2_DE 0x02 /* Discard elligability */
98 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */
99
100 /* Used to do headers */
101 const static struct segment {
102 u_char mask;
103 u_char shift;
104 u_char width;
105 } makeup[] = {
106 { 0xfc, 2, 6 },
107 { 0xf0, 4, 4 },
108 { 0xfe, 1, 7 },
109 { 0xfc, 2, 6 }
110 };
111
112 #define SHIFTIN(segment, byte, dlci) \
113 { \
114 (dlci) <<= (segment)->width; \
115 (dlci) |= \
116 (((byte) & (segment)->mask) >> (segment)->shift); \
117 }
118
119 #define SHIFTOUT(segment, byte, dlci) \
120 { \
121 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \
122 (dlci) >>= (segment)->width; \
123 }
124
125 /* Netgraph methods */
126 static ng_constructor_t ngfrm_constructor;
127 static ng_shutdown_t ngfrm_shutdown;
128 static ng_newhook_t ngfrm_newhook;
129 static ng_rcvdata_t ngfrm_rcvdata;
130 static ng_disconnect_t ngfrm_disconnect;
131
132 /* Other internal functions */
133 static int ngfrm_decode(node_p node, item_p item);
134 static int ngfrm_addrlen(char *hdr);
135 static int ngfrm_allocate_CTX(sc_p sc, int dlci);
136
137 /* Netgraph type */
138 static struct ng_type typestruct = {
139 .version = NG_ABI_VERSION,
140 .name = NG_FRAMERELAY_NODE_TYPE,
141 .constructor = ngfrm_constructor,
142 .shutdown = ngfrm_shutdown,
143 .newhook = ngfrm_newhook,
144 .rcvdata = ngfrm_rcvdata,
145 .disconnect = ngfrm_disconnect,
146 };
147 NETGRAPH_INIT(framerelay, &typestruct);
148
149 #define ERROUT(x) do { error = (x); goto done; } while (0)
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
ngfrm_allocate_CTX(sc_p sc,int dlci)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
ngfrm_constructor(node_p node)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
ngfrm_newhook(node_p node,hook_p hook,const char * name)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 /* It must be the downstream connection */
254 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
255 return EINVAL;
256
257 /* Make sure we haven't already got one (paranoid) */
258 if (sc->downstream.hook)
259 return (EADDRINUSE);
260
261 /* OK add it */
262 NG_HOOK_SET_PRIVATE(hook, &sc->downstream);
263 sc->downstream.hook = hook;
264 sc->downstream.dlci = -1;
265 sc->downstream.flags |= CHAN_ACTIVE;
266 sc->datahooks++;
267 return (0);
268 }
269
270 /* Must be a dlci hook at this point */
271 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
272 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
273 return (EINVAL);
274 dlci = (int)strtoul(cp, &eptr, 10);
275 if (*eptr != '\0' || dlci < 0 || dlci > 1023)
276 return (EINVAL);
277
278 /*
279 * We have a dlci, now either find it, or allocate it. It's possible
280 * that we might have seen packets for it already and made an entry
281 * for it.
282 */
283 ctxnum = ngfrm_allocate_CTX(sc, dlci);
284 if (ctxnum == -1)
285 return (ENOBUFS);
286
287 /*
288 * Be paranoid: if it's got a hook already, that dlci is in use .
289 * Generic code can not catch all the synonyms (e.g. dlci016 vs
290 * dlci16)
291 */
292 if (sc->channel[ctxnum].hook != NULL)
293 return (EADDRINUSE);
294
295 /*
296 * Put our hooks into it (pun not intended)
297 */
298 sc->channel[ctxnum].flags |= CHAN_ACTIVE;
299 NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum);
300 sc->channel[ctxnum].hook = hook;
301 sc->datahooks++;
302 return (0);
303 }
304
305 /*
306 * Count up the size of the address header if we don't already know
307 */
308 int
ngfrm_addrlen(char * hdr)309 ngfrm_addrlen(char *hdr)
310 {
311 if (hdr[0] & BYTEX_EA)
312 return 0;
313 if (hdr[1] & BYTEX_EA)
314 return 2;
315 if (hdr[2] & BYTEX_EA)
316 return 3;
317 if (hdr[3] & BYTEX_EA)
318 return 4;
319 return 0;
320 }
321
322 /*
323 * Receive data packet
324 */
325 static int
ngfrm_rcvdata(hook_p hook,item_p item)326 ngfrm_rcvdata(hook_p hook, item_p item)
327 {
328 struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook);
329 struct mbuf *m = NULL;
330 int error = 0;
331 int dlci;
332 sc_p sc;
333 int alen;
334 char *data;
335
336 /* Data doesn't come in from just anywhere (e.g debug hook) */
337 if (ctxp == NULL)
338 ERROUT(ENETDOWN);
339
340 /* If coming from downstream, decode it to a channel */
341 dlci = ctxp->dlci;
342 if (dlci == -1)
343 return (ngfrm_decode(NG_HOOK_NODE(hook), item));
344
345 NGI_GET_M(item, m);
346 /* Derive the softc we will need */
347 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
348
349 /* If there is no live channel, throw it away */
350 if ((sc->downstream.hook == NULL)
351 || ((ctxp->flags & CHAN_ACTIVE) == 0))
352 ERROUT(ENETDOWN);
353
354 /* Store the DLCI on the front of the packet */
355 alen = sc->addrlen;
356 if (alen == 0)
357 alen = 2; /* default value for transmit */
358 M_PREPEND(m, alen, M_NOWAIT);
359 if (m == NULL)
360 ERROUT(ENOBUFS);
361 data = mtod(m, char *);
362
363 /*
364 * Shift the lowest bits into the address field until we are done.
365 * First byte is MSBits of addr so work backwards.
366 */
367 switch (alen) {
368 case 2:
369 data[0] = data[1] = '\0';
370 SHIFTOUT(makeup + 1, data[1], dlci);
371 SHIFTOUT(makeup + 0, data[0], dlci);
372 data[1] |= BYTEX_EA;
373 break;
374 case 3:
375 data[0] = data[1] = data[2] = '\0';
376 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
377 SHIFTOUT(makeup + 1, data[1], dlci);
378 SHIFTOUT(makeup + 0, data[0], dlci);
379 data[2] |= BYTEX_EA;
380 break;
381 case 4:
382 data[0] = data[1] = data[2] = data[3] = '\0';
383 SHIFTOUT(makeup + 3, data[3], dlci);
384 SHIFTOUT(makeup + 2, data[2], dlci);
385 SHIFTOUT(makeup + 1, data[1], dlci);
386 SHIFTOUT(makeup + 0, data[0], dlci);
387 data[3] |= BYTEX_EA;
388 break;
389 default:
390 panic("%s", __func__);
391 }
392
393 /* Send it */
394 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m);
395 return (error);
396
397 done:
398 NG_FREE_ITEM(item);
399 NG_FREE_M(m);
400 return (error);
401 }
402
403 /*
404 * Decode an incoming frame coming from the switch
405 */
406 static int
ngfrm_decode(node_p node,item_p item)407 ngfrm_decode(node_p node, item_p item)
408 {
409 const sc_p sc = NG_NODE_PRIVATE(node);
410 char *data;
411 int alen;
412 u_int dlci = 0;
413 int error = 0;
414 int ctxnum;
415 struct mbuf *m;
416
417 NGI_GET_M(item, m);
418 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
419 ERROUT(ENOBUFS);
420 data = mtod(m, char *);
421 if ((alen = sc->addrlen) == 0) {
422 sc->addrlen = alen = ngfrm_addrlen(data);
423 }
424 switch (alen) {
425 case 2:
426 SHIFTIN(makeup + 0, data[0], dlci);
427 SHIFTIN(makeup + 1, data[1], dlci);
428 break;
429 case 3:
430 SHIFTIN(makeup + 0, data[0], dlci);
431 SHIFTIN(makeup + 1, data[1], dlci);
432 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */
433 break;
434 case 4:
435 SHIFTIN(makeup + 0, data[0], dlci);
436 SHIFTIN(makeup + 1, data[1], dlci);
437 SHIFTIN(makeup + 2, data[2], dlci);
438 SHIFTIN(makeup + 3, data[3], dlci);
439 break;
440 default:
441 ERROUT(EINVAL);
442 }
443
444 if (dlci > 1023)
445 ERROUT(EINVAL);
446 ctxnum = sc->ALT[dlci];
447 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
448 /* Send it */
449 m_adj(m, alen);
450 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m);
451 return (error);
452 } else {
453 error = ENETDOWN;
454 }
455 done:
456 NG_FREE_ITEM(item);
457 NG_FREE_M(m);
458 return (error);
459 }
460
461 /*
462 * Shutdown node
463 */
464 static int
ngfrm_shutdown(node_p node)465 ngfrm_shutdown(node_p node)
466 {
467 const sc_p sc = NG_NODE_PRIVATE(node);
468
469 NG_NODE_SET_PRIVATE(node, NULL);
470 free(sc, M_NETGRAPH);
471 NG_NODE_UNREF(node);
472 return (0);
473 }
474
475 /*
476 * Hook disconnection
477 *
478 * Invalidate the private data associated with this dlci.
479 * For this type, removal of the last link resets tries to destroy the node.
480 */
481 static int
ngfrm_disconnect(hook_p hook)482 ngfrm_disconnect(hook_p hook)
483 {
484 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
485 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook);
486 int dlci;
487
488 /* If it's a regular dlci hook, then free resources etc.. */
489 if (cp != NULL) {
490 cp->hook = NULL;
491 dlci = cp->dlci;
492 if (dlci != -1)
493 sc->ALT[dlci] = 0;
494 cp->flags = 0;
495 sc->datahooks--;
496 }
497 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
498 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
499 ng_rmnode_self(NG_HOOK_NODE(hook));
500 return (0);
501 }
502