FreeBSD/Linux Kernel Cross Reference
sys/net/if_sl.c
1 /*-
2 * Copyright (c) 1987, 1989, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)if_sl.c 8.6 (Berkeley) 2/1/94
30 * $FreeBSD$
31 */
32
33 /*
34 * Serial Line interface
35 *
36 * Rick Adams
37 * Center for Seismic Studies
38 * 1300 N 17th Street, Suite 1450
39 * Arlington, Virginia 22209
40 * (703)276-7900
41 * rick@seismo.ARPA
42 * seismo!rick
43 *
44 * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
45 * N.B.: this belongs in netinet, not net, the way it stands now.
46 * Should have a link-layer type designation, but wouldn't be
47 * backwards-compatible.
48 *
49 * Converted to 4.3BSD Beta by Chris Torek.
50 * Other changes made at Berkeley, based in part on code by Kirk Smith.
51 * W. Jolitz added slip abort.
52 *
53 * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
54 * Added priority queuing for "interactive" traffic; hooks for TCP
55 * header compression; ICMP filtering (at 2400 baud, some cretin
56 * pinging you can use up all your bandwidth). Made low clist behavior
57 * more robust and slightly less likely to hang serial line.
58 * Sped up a bunch of things.
59 *
60 * Note that splimp() is used throughout to block both (tty) input
61 * interrupts and network activity; thus, splimp must be >= spltty.
62 */
63
64 #include "opt_inet.h"
65 #include "opt_slip.h"
66
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/malloc.h>
70 #include <sys/mbuf.h>
71 #include <sys/priv.h>
72 #include <sys/proc.h>
73 #include <sys/socket.h>
74 #include <sys/sockio.h>
75 #include <sys/fcntl.h>
76 #include <sys/signalvar.h>
77 #include <sys/tty.h>
78 #include <sys/clist.h>
79 #include <sys/kernel.h>
80 #include <sys/conf.h>
81 #include <sys/module.h>
82 #include <sys/proc.h>
83
84 #include <net/if.h>
85 #include <net/if_types.h>
86 #include <net/netisr.h>
87
88 #if INET
89 #include <netinet/in.h>
90 #include <netinet/in_systm.h>
91 #include <netinet/in_var.h>
92 #include <netinet/ip.h>
93 #else
94 #error "Huh? Slip without inet?"
95 #endif
96
97 #include <net/slcompress.h>
98 #include <net/if_slvar.h>
99 #include <net/slip.h>
100
101 #include <net/bpf.h>
102
103 static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface");
104
105 /*
106 * SLRMAX is a hard limit on input packet size. To simplify the code
107 * and improve performance, we require that packets fit in an mbuf
108 * cluster, and if we get a compressed packet, there's enough extra
109 * room to expand the header into a max length tcp/ip header (128
110 * bytes). So, SLRMAX can be at most
111 * MCLBYTES - 128
112 *
113 * SLMTU is the default transmit MTU. The transmit MTU should be kept
114 * small enough so that interactive use doesn't suffer, but large
115 * enough to provide good performance. 552 is a good choice for SLMTU
116 * because it is high enough to not fragment TCP packets being routed
117 * through this host. Packet fragmentation is bad with SLIP because
118 * fragment headers aren't compressed. The previous assumptions about
119 * the best MTU value don't really hold when using modern modems with
120 * BTLZ data compression because the modem buffers play a much larger
121 * role in interactive performance than the MTU. The MTU can be changed
122 * at any time to suit the specific environment with ifconfig(8), and
123 * its maximum value is defined as SLTMAX. SLTMAX must not be so large
124 * that it would overflow the stack if BPF is configured (XXX; if_ppp.c
125 * handles this better).
126 *
127 * SLIP_HIWAT is the amount of data that will be queued 'downstream'
128 * of us (i.e., in clists waiting to be picked up by the tty output
129 * interrupt). If we queue a lot of data downstream, it's immune to
130 * our t.o.s. queuing.
131 * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
132 * telnet/ftp will see a 1 sec wait, independent of the mtu (the
133 * wait is dependent on the ftp window size but that's typically
134 * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize
135 * the cost (in idle time on the wire) of the tty driver running
136 * off the end of its clists & having to call back slstart for a
137 * new packet. For a tty interface with any buffering at all, this
138 * cost will be zero. Even with a totally brain dead interface (like
139 * the one on a typical workstation), the cost will be <= 1 character
140 * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
141 * at most 1% while maintaining good interactive response.
142 */
143 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
144 #define SLRMAX (MCLBYTES - BUFOFFSET)
145 #define SLBUFSIZE (SLRMAX + BUFOFFSET)
146 #ifndef SLMTU
147 #define SLMTU 552 /* default MTU */
148 #endif
149 #define SLTMAX 1500 /* maximum MTU */
150 #define SLIP_HIWAT roundup(50,CBSIZE)
151 #define CLISTRESERVE 1024 /* Can't let clists get too low */
152
153 /*
154 * SLIP ABORT ESCAPE MECHANISM:
155 * (inspired by HAYES modem escape arrangement)
156 * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
157 * within window time signals a "soft" exit from slip mode by remote end
158 * if the IFF_DEBUG flag is on.
159 */
160 #define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/
161 #define ABT_IDLE 1 /* in seconds - idle before an escape */
162 #define ABT_COUNT 3 /* count of escapes for abort */
163 #define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */
164
165 static LIST_HEAD(sl_list, sl_softc) sl_list;
166
167 #define FRAME_END 0xc0 /* Frame End */
168 #define FRAME_ESCAPE 0xdb /* Frame Esc */
169 #define TRANS_FRAME_END 0xdc /* transposed frame end */
170 #define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */
171
172 static int slisstatic(int);
173 static void slmarkstatic(int);
174 static struct sl_softc *slcreate(void);
175 static void sldestroy(struct sl_softc *sc);
176 static struct mbuf *sl_btom(struct sl_softc *, int);
177 static timeout_t sl_keepalive;
178 static timeout_t sl_outfill;
179 static l_close_t slclose;
180 static l_rint_t slinput;
181 static l_ioctl_t sltioctl;
182 static l_start_t sltstart;
183 static int slioctl(struct ifnet *, u_long, caddr_t);
184 static int slopen(struct cdev *, struct tty *);
185 static int sloutput(struct ifnet *,
186 struct mbuf *, struct sockaddr *, struct rtentry *);
187 static void slstart(struct ifnet *);
188
189 static struct linesw slipdisc = {
190 .l_open = slopen,
191 .l_close = slclose,
192 .l_read = l_noread,
193 .l_write = l_nowrite,
194 .l_ioctl = sltioctl,
195 .l_rint = slinput,
196 .l_start = sltstart,
197 .l_modem = ttymodem
198 };
199
200 /*
201 * Called from boot code to establish sl interfaces.
202 */
203 static int
204 sl_modevent(module_t mod, int type, void *data)
205 {
206 switch (type) {
207 case MOD_LOAD:
208 ldisc_register(SLIPDISC, &slipdisc);
209 LIST_INIT(&sl_list);
210 break;
211 case MOD_UNLOAD:
212 ldisc_deregister(SLIPDISC);
213 printf("if_sl module unload - not possible for this module type\n");
214 return EINVAL;
215 default:
216 return EOPNOTSUPP;
217 }
218 return 0;
219 }
220
221 static moduledata_t sl_mod = {
222 "if_sl",
223 sl_modevent,
224 0
225 };
226
227 DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
228
229 static int *st_unit_list;
230 static size_t st_unit_max = 0;
231
232 static int
233 slisunitfree(int unit)
234 {
235 struct sl_softc *sc;
236
237 LIST_FOREACH(sc, &sl_list, sl_next) {
238 if (SL2IFP(sc)->if_dunit == unit)
239 return (0);
240 }
241 return (1);
242 }
243
244 static struct sl_softc *
245 sl_for_tty(struct tty *tp)
246 {
247 struct sl_softc *nc;
248
249 LIST_FOREACH(nc, &sl_list, sl_next) {
250 if (nc->sc_ttyp == tp)
251 return (nc);
252 }
253 return (NULL);
254 }
255 static int
256 slisstatic(int unit)
257 {
258 size_t i;
259
260 for (i = 0; i < st_unit_max; i++)
261 if (st_unit_list[i] == unit)
262 return 1;
263 return 0;
264 }
265
266 static void
267 slmarkstatic(int unit)
268 {
269 int *t;
270
271 if (slisstatic(unit))
272 return;
273
274 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT);
275 if (t == NULL)
276 return;
277
278 if (st_unit_list) {
279 bcopy(st_unit_list, t, sizeof(int) * st_unit_max);
280 free(st_unit_list, M_SL);
281 }
282 st_unit_list = t;
283 st_unit_list[st_unit_max] = unit;
284 st_unit_max++;
285 }
286
287 static struct sl_softc *
288 slcreate(void)
289 {
290 struct sl_softc *sc;
291 int unit;
292 struct mbuf *m;
293
294 MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO);
295 sc->sc_ifp = if_alloc(IFT_SLIP);
296 if (sc->sc_ifp == NULL) {
297 free(sc, M_SL);
298 return (NULL);
299 }
300
301 m = m_gethdr(M_TRYWAIT, MT_DATA);
302 if (m != NULL) {
303 MCLGET(m, M_TRYWAIT);
304 if ((m->m_flags & M_EXT) == 0) {
305 m_free(m);
306 m = NULL;
307 }
308 }
309
310 if (m == NULL) {
311 printf("sl: can't allocate buffer\n");
312 free(sc, M_SL);
313 return (NULL);
314 }
315
316 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
317 sc->sc_mbuf = m;
318 sc->sc_buf = sc->sc_ep - SLRMAX;
319 sc->sc_mp = sc->sc_buf;
320 sl_compress_init(&sc->sc_comp, -1);
321
322 SL2IFP(sc)->if_softc = sc;
323 SL2IFP(sc)->if_mtu = SLMTU;
324 SL2IFP(sc)->if_flags =
325 #ifdef SLIP_IFF_OPTS
326 SLIP_IFF_OPTS;
327 #else
328 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST | IFF_NEEDSGIANT;
329 #endif
330 SL2IFP(sc)->if_ioctl = slioctl;
331 SL2IFP(sc)->if_output = sloutput;
332 SL2IFP(sc)->if_start = slstart;
333 SL2IFP(sc)->if_snd.ifq_maxlen = 50;
334 sc->sc_fastq.ifq_maxlen = 32;
335 SL2IFP(sc)->if_linkmib = sc;
336 SL2IFP(sc)->if_linkmiblen = sizeof *sc;
337 mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF);
338
339 /*
340 * Find a suitable unit number.
341 */
342 for (unit=0; ; unit++) {
343 if (slisstatic(unit))
344 continue;
345 if (!slisunitfree(unit))
346 continue;
347 break;
348 }
349 if_initname(SL2IFP(sc), "sl", unit);
350 LIST_INSERT_HEAD(&sl_list, sc, sl_next);
351
352 if_attach(SL2IFP(sc));
353 bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN);
354
355 return sc;
356 }
357
358
359 /*
360 * Line specific open routine.
361 * Attach the given tty to the first available sl unit.
362 */
363 /* ARGSUSED */
364 static int
365 slopen(struct cdev *dev, register struct tty *tp)
366 {
367 register struct sl_softc *sc;
368 int s, error;
369
370 error = priv_check(curthread, PRIV_NET_SLIP);
371 if (error)
372 return (error);
373
374 if ((sc = slcreate()) == NULL)
375 return (ENOBUFS);
376
377 tp->t_hotchar = FRAME_END;
378 sc->sc_ttyp = tp;
379 SL2IFP(sc)->if_baudrate = tp->t_ospeed;
380 ttyflush(tp, FREAD | FWRITE);
381
382 /*
383 * We don't use t_canq or t_rawq, so reduce their
384 * cblock resources to 0. Reserve enough cblocks
385 * for t_outq to guarantee that we can fit a full
386 * packet if the SLIP_HIWAT check allows slstart()
387 * to loop. Use the same value for the cblock
388 * limit since the reserved blocks should always
389 * be enough. Reserving cblocks probably makes
390 * the CLISTRESERVE check unnecessary and wasteful.
391 */
392 clist_alloc_cblocks(&tp->t_canq, 0, 0);
393 clist_alloc_cblocks(&tp->t_outq,
394 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1,
395 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1);
396 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
397
398 s = splnet();
399 if_up(SL2IFP(sc));
400 splx(s);
401 return (0);
402 }
403
404 static void
405 sldestroy(struct sl_softc *sc)
406 {
407 bpfdetach(SL2IFP(sc));
408 if_detach(SL2IFP(sc));
409 if_free(SL2IFP(sc));
410 LIST_REMOVE(sc, sl_next);
411 m_free(sc->sc_mbuf);
412 mtx_destroy(&sc->sc_fastq.ifq_mtx);
413 if (sc->bpfbuf)
414 free(sc->bpfbuf, M_SL);
415 free(sc, M_SL);
416 }
417
418 /*
419 * Line specific close routine.
420 * Detach the tty from the sl unit.
421 */
422 static int
423 slclose(struct tty *tp, int flag)
424 {
425 register struct sl_softc *sc;
426 int s;
427
428 ttyflush(tp, FREAD | FWRITE);
429 /*
430 * XXX the placement of the following spl is misleading. tty
431 * interrupts must be blocked across line discipline switches
432 * and throughout closes to avoid races.
433 */
434 s = splimp(); /* actually, max(spltty, splnet) */
435 clist_free_cblocks(&tp->t_outq);
436 sc = sl_for_tty(tp);
437 if (sc != NULL) {
438 if (sc->sc_outfill) {
439 sc->sc_outfill = 0;
440 untimeout(sl_outfill, sc, sc->sc_ofhandle);
441 }
442 if (sc->sc_keepalive) {
443 sc->sc_keepalive = 0;
444 untimeout(sl_keepalive, sc, sc->sc_kahandle);
445 }
446 if_down(SL2IFP(sc));
447 sc->sc_ttyp = NULL;
448 sldestroy(sc);
449 }
450 splx(s);
451 return 0;
452 }
453
454 /*
455 * Line specific (tty) ioctl routine.
456 * Provide a way to get the sl unit number.
457 */
458 /* ARGSUSED */
459 static int
460 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag,
461 struct thread *td)
462 {
463 struct sl_softc *sc = sl_for_tty(tp);
464 int s, unit, wasup;
465
466 s = splimp();
467 switch (cmd) {
468 case SLIOCGUNIT:
469 *(int *)data = SL2IFP(sc)->if_dunit;
470 break;
471
472 case SLIOCSUNIT:
473 unit = *(u_int *)data;
474 if (unit < 0) {
475 splx(s);
476 return (ENXIO);
477 }
478 if (SL2IFP(sc)->if_dunit != unit) {
479 if (!slisunitfree(unit)) {
480 splx(s);
481 return (ENXIO);
482 }
483
484 wasup = SL2IFP(sc)->if_flags & IFF_UP;
485 bpfdetach(SL2IFP(sc));
486 if_detach(SL2IFP(sc));
487 LIST_REMOVE(sc, sl_next);
488 if_initname(SL2IFP(sc), "sl", unit);
489 LIST_INSERT_HEAD(&sl_list, sc, sl_next);
490 if_attach(SL2IFP(sc));
491 bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN);
492 if (wasup)
493 if_up(SL2IFP(sc));
494 else
495 if_down(SL2IFP(sc));
496 clist_alloc_cblocks(&tp->t_outq,
497 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1,
498 SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1);
499 }
500 slmarkstatic(unit);
501 break;
502
503 case SLIOCSKEEPAL:
504 sc->sc_keepalive = *(u_int *)data * hz;
505 if (sc->sc_keepalive) {
506 sc->sc_flags |= SC_KEEPALIVE;
507 sc->sc_kahandle = timeout(sl_keepalive, sc,
508 sc->sc_keepalive);
509 } else {
510 if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
511 untimeout(sl_keepalive, sc, sc->sc_kahandle);
512 sc->sc_flags &= ~SC_KEEPALIVE;
513 }
514 }
515 break;
516
517 case SLIOCGKEEPAL:
518 *(int *)data = sc->sc_keepalive / hz;
519 break;
520
521 case SLIOCSOUTFILL:
522 sc->sc_outfill = *(u_int *)data * hz;
523 if (sc->sc_outfill) {
524 sc->sc_flags |= SC_OUTWAIT;
525 sc->sc_ofhandle = timeout(sl_outfill, sc,
526 sc->sc_outfill);
527 } else {
528 if ((sc->sc_flags & SC_OUTWAIT) != 0) {
529 untimeout(sl_outfill, sc, sc->sc_ofhandle);
530 sc->sc_flags &= ~SC_OUTWAIT;
531 }
532 }
533 break;
534
535 case SLIOCGOUTFILL:
536 *(int *)data = sc->sc_outfill / hz;
537 break;
538
539 default:
540 splx(s);
541 return (ENOIOCTL);
542 }
543 splx(s);
544 return (0);
545 }
546
547 /*
548 * Queue a packet. Start transmission if not active.
549 * Compression happens in slstart; if we do it here, IP TOS
550 * will cause us to not compress "background" packets, because
551 * ordering gets trashed. It can be done for all packets in slstart.
552 */
553 static int
554 sloutput(struct ifnet *ifp, register struct mbuf *m, struct sockaddr *dst,
555 struct rtentry *rtp)
556 {
557 register struct sl_softc *sc = ifp->if_softc;
558 register struct ip *ip;
559 int error;
560
561 /*
562 * `Cannot happen' (see slioctl). Someday we will extend
563 * the line protocol to support other address families.
564 */
565 if (dst->sa_family != AF_INET) {
566 if_printf(ifp, "af%d not supported\n", dst->sa_family);
567 m_freem(m);
568 SL2IFP(sc)->if_noproto++;
569 return (EAFNOSUPPORT);
570 }
571
572 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
573 m_freem(m);
574 return (ENETDOWN);
575 }
576 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
577 m_freem(m);
578 return (EHOSTUNREACH);
579 }
580 ip = mtod(m, struct ip *);
581 if (SL2IFP(sc)->if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
582 m_freem(m);
583 return (ENETRESET); /* XXX ? */
584 }
585 if (ip->ip_tos & IPTOS_LOWDELAY &&
586 !ALTQ_IS_ENABLED(&SL2IFP(sc)->if_snd))
587 error = !(IF_HANDOFF(&sc->sc_fastq, m, SL2IFP(sc)));
588 else
589 IFQ_HANDOFF(SL2IFP(sc), m, error);
590 if (error) {
591 SL2IFP(sc)->if_oerrors++;
592 return (ENOBUFS);
593 }
594 return (0);
595 }
596
597 static void
598 slstart(struct ifnet *ifp)
599 {
600 struct sl_softc *sc = ifp->if_softc;
601 int s;
602
603 s = splimp();
604 if (sc->sc_ttyp->t_outq.c_cc == 0)
605 sltstart(sc->sc_ttyp);
606 splx(s);
607 }
608
609 /*
610 * Start output on interface. Get another datagram
611 * to send from the interface queue and map it to
612 * the interface before starting output.
613 */
614 static int
615 sltstart(struct tty *tp)
616 {
617 register struct sl_softc *sc = sl_for_tty(tp);
618 register struct mbuf *m;
619 register u_char *cp;
620 register struct ip *ip;
621 int s;
622 register int len = 0;
623
624 GIANT_REQUIRED; /* tty */
625
626 for (;;) {
627 /*
628 * Call output process whether or not there is more in the
629 * output queue. We are being called in lieu of ttstart
630 * and must do what it would.
631 */
632 tt_oproc(tp);
633
634 if (tp->t_outq.c_cc != 0) {
635 if (sc != NULL)
636 sc->sc_flags &= ~SC_OUTWAIT;
637 if (tp->t_outq.c_cc > SLIP_HIWAT)
638 return 0;
639 }
640
641 /*
642 * This happens briefly when the line shuts down.
643 */
644 if (sc == NULL)
645 return 0;
646
647 /*
648 * Get a packet and send it to the interface.
649 */
650 s = splimp();
651 IF_DEQUEUE(&sc->sc_fastq, m);
652 if (m)
653 SL2IFP(sc)->if_omcasts++; /* XXX */
654 else
655 IF_DEQUEUE(&SL2IFP(sc)->if_snd, m);
656 splx(s);
657 if (m == NULL)
658 return 0;
659
660 /*
661 * We do the header compression here rather than in sloutput
662 * because the packets will be out of order if we are using TOS
663 * queueing, and the connection id compression will get
664 * munged when this happens.
665 */
666 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
667 /*
668 * We need to save the TCP/IP header before it's
669 * compressed. To avoid complicated code, we just
670 * copy the entire packet into a stack buffer (since
671 * this is a serial line, packets should be short
672 * and/or the copy should be negligible cost compared
673 * to the packet transmission time).
674 */
675 register struct mbuf *m1 = m;
676 register u_char *cp;
677
678 if (sc->bpfbuf == NULL)
679 MALLOC(sc->bpfbuf, u_char *,
680 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT);
681
682 if (sc->bpfbuf) {
683 cp = sc->bpfbuf + SLIP_HDRLEN;
684 len = 0;
685 do {
686 register int mlen = m1->m_len;
687
688 bcopy(mtod(m1, caddr_t), cp, mlen);
689 cp += mlen;
690 len += mlen;
691 } while ((m1 = m1->m_next) != NULL);
692 }
693 }
694 ip = mtod(m, struct ip *);
695 if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
696 if (SL2IFP(sc)->if_flags & SC_COMPRESS)
697 *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
698 &sc->sc_comp, 1);
699 }
700 if (bpf_peers_present(SL2IFP(sc)->if_bpf) && sc->bpfbuf) {
701 /*
702 * Put the SLIP pseudo-"link header" in place. The
703 * compressed header is now at the beginning of the
704 * mbuf.
705 */
706 sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT;
707 bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN);
708 BPF_TAP(SL2IFP(sc), sc->bpfbuf, len + SLIP_HDRLEN);
709 }
710
711 /*
712 * If system is getting low on clists, just flush our
713 * output queue (if the stuff was important, it'll get
714 * retransmitted). Note that SLTMAX is used instead of
715 * the current if_mtu setting because connections that
716 * have already been established still use the original
717 * (possibly larger) mss.
718 */
719 if (cfreecount < CLISTRESERVE + SLTMAX) {
720 m_freem(m);
721 SL2IFP(sc)->if_collisions++;
722 continue;
723 }
724
725 sc->sc_flags &= ~SC_OUTWAIT;
726 /*
727 * The extra FRAME_END will start up a new packet, and thus
728 * will flush any accumulated garbage. We do this whenever
729 * the line may have been idle for some time.
730 */
731 if (tp->t_outq.c_cc == 0) {
732 ++SL2IFP(sc)->if_obytes;
733 (void) putc(FRAME_END, &tp->t_outq);
734 }
735
736 while (m) {
737 register u_char *ep;
738
739 cp = mtod(m, u_char *); ep = cp + m->m_len;
740 while (cp < ep) {
741 /*
742 * Find out how many bytes in the string we can
743 * handle without doing something special.
744 */
745 register u_char *bp = cp;
746
747 while (cp < ep) {
748 switch (*cp++) {
749 case FRAME_ESCAPE:
750 case FRAME_END:
751 --cp;
752 goto out;
753 }
754 }
755 out:
756 if (cp > bp) {
757 /*
758 * Put n characters at once
759 * into the tty output queue.
760 */
761 if (b_to_q((char *)bp, cp - bp,
762 &tp->t_outq))
763 break;
764 SL2IFP(sc)->if_obytes += cp - bp;
765 }
766 /*
767 * If there are characters left in the mbuf,
768 * the first one must be special..
769 * Put it out in a different form.
770 */
771 if (cp < ep) {
772 if (putc(FRAME_ESCAPE, &tp->t_outq))
773 break;
774 if (putc(*cp++ == FRAME_ESCAPE ?
775 TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
776 &tp->t_outq)) {
777 (void) unputc(&tp->t_outq);
778 break;
779 }
780 SL2IFP(sc)->if_obytes += 2;
781 }
782 }
783 m = m_free(m);
784 }
785
786 if (putc(FRAME_END, &tp->t_outq)) {
787 /*
788 * Not enough room. Remove a char to make room
789 * and end the packet normally.
790 * If you get many collisions (more than one or two
791 * a day) you probably do not have enough clists
792 * and you should increase "nclist" in param.c.
793 */
794 (void) unputc(&tp->t_outq);
795 (void) putc(FRAME_END, &tp->t_outq);
796 SL2IFP(sc)->if_collisions++;
797 } else {
798 ++SL2IFP(sc)->if_obytes;
799 SL2IFP(sc)->if_opackets++;
800 }
801 }
802 return 0;
803 }
804
805 /*
806 * Copy data buffer to mbuf chain; add ifnet pointer.
807 */
808 static struct mbuf *
809 sl_btom(struct sl_softc *sc, register int len)
810 {
811 struct mbuf *m, *newm;
812
813 MGETHDR(m, M_DONTWAIT, MT_DATA);
814 if (m == NULL)
815 return (NULL);
816
817 /*
818 * If we have more than MHLEN bytes, it's cheaper to
819 * queue the cluster we just filled & allocate a new one
820 * for the input buffer. Otherwise, fill the mbuf we
821 * allocated above. Note that code in the input routine
822 * guarantees that packet will fit in a cluster.
823 */
824 if (len >= MHLEN) {
825 MCLGET(m, M_DONTWAIT);
826 if ((m->m_flags & M_EXT) == 0) {
827 /*
828 * we couldn't get a cluster - if memory's this
829 * low, it's time to start dropping packets.
830 */
831 (void) m_free(m);
832 return (NULL);
833 }
834 /* Swap the new and old clusters */
835 newm = m;
836 m = sc->sc_mbuf;
837 sc->sc_mbuf = newm;
838 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE;
839
840 m->m_data = (caddr_t)sc->sc_buf;
841 } else
842 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
843
844 m->m_len = len;
845 m->m_pkthdr.len = len;
846 m->m_pkthdr.rcvif = SL2IFP(sc);
847 return (m);
848 }
849
850 /*
851 * tty interface receiver interrupt.
852 */
853 static int
854 slinput(int c, struct tty *tp)
855 {
856 register struct sl_softc *sc;
857 register struct mbuf *m;
858 register int len;
859 u_char chdr[CHDR_LEN];
860
861 tk_nin++;
862 sc = sl_for_tty(tp);
863 if (sc == NULL)
864 return 0;
865 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
866 sc->sc_flags |= SC_ERROR;
867 return 0;
868 }
869 c &= TTY_CHARMASK;
870
871 ++SL2IFP(sc)->if_ibytes;
872
873 if (SL2IFP(sc)->if_flags & IFF_DEBUG) {
874 if (c == ABT_ESC) {
875 /*
876 * If we have a previous abort, see whether
877 * this one is within the time limit.
878 */
879 if (sc->sc_abortcount &&
880 time_uptime >= sc->sc_starttime + ABT_WINDOW)
881 sc->sc_abortcount = 0;
882 /*
883 * If we see an abort after "idle" time, count it;
884 * record when the first abort escape arrived.
885 */
886 if (time_uptime >= sc->sc_lasttime + ABT_IDLE) {
887 if (++sc->sc_abortcount == 1)
888 sc->sc_starttime = time_uptime;
889 if (sc->sc_abortcount >= ABT_COUNT) {
890 slclose(tp,0);
891 return 0;
892 }
893 }
894 } else
895 sc->sc_abortcount = 0;
896 sc->sc_lasttime = time_uptime;
897 }
898
899 switch (c) {
900
901 case TRANS_FRAME_ESCAPE:
902 if (sc->sc_escape)
903 c = FRAME_ESCAPE;
904 break;
905
906 case TRANS_FRAME_END:
907 if (sc->sc_escape)
908 c = FRAME_END;
909 break;
910
911 case FRAME_ESCAPE:
912 sc->sc_escape = 1;
913 return 0;
914
915 case FRAME_END:
916 sc->sc_flags &= ~SC_KEEPALIVE;
917 if(sc->sc_flags & SC_ERROR) {
918 sc->sc_flags &= ~SC_ERROR;
919 goto newpack;
920 }
921 len = sc->sc_mp - sc->sc_buf;
922 if (len < 3)
923 /* less than min length packet - ignore */
924 goto newpack;
925
926 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
927 /*
928 * Save the compressed header, so we
929 * can tack it on later. Note that we
930 * will end up copying garbage in some
931 * cases but this is okay. We remember
932 * where the buffer started so we can
933 * compute the new header length.
934 */
935 bcopy(sc->sc_buf, chdr, CHDR_LEN);
936 }
937
938 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
939 if (c & 0x80)
940 c = TYPE_COMPRESSED_TCP;
941 else if (c == TYPE_UNCOMPRESSED_TCP)
942 *sc->sc_buf &= 0x4f; /* XXX */
943 /*
944 * We've got something that's not an IP packet.
945 * If compression is enabled, try to decompress it.
946 * Otherwise, if `auto-enable' compression is on and
947 * it's a reasonable packet, decompress it and then
948 * enable compression. Otherwise, drop it.
949 */
950 if (SL2IFP(sc)->if_flags & SC_COMPRESS) {
951 len = sl_uncompress_tcp(&sc->sc_buf, len,
952 (u_int)c, &sc->sc_comp);
953 if (len <= 0)
954 goto error;
955 } else if ((SL2IFP(sc)->if_flags & SC_AUTOCOMP) &&
956 c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
957 len = sl_uncompress_tcp(&sc->sc_buf, len,
958 (u_int)c, &sc->sc_comp);
959 if (len <= 0)
960 goto error;
961 SL2IFP(sc)->if_flags |= SC_COMPRESS;
962 } else
963 goto error;
964 }
965 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
966 /*
967 * Put the SLIP pseudo-"link header" in place.
968 * We couldn't do this any earlier since
969 * decompression probably moved the buffer
970 * pointer. Then, invoke BPF.
971 */
972 register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
973
974 hp[SLX_DIR] = SLIPDIR_IN;
975 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
976 BPF_TAP(SL2IFP(sc), hp, len + SLIP_HDRLEN);
977 }
978 m = sl_btom(sc, len);
979 if (m == NULL)
980 goto error;
981
982 SL2IFP(sc)->if_ipackets++;
983
984 if ((SL2IFP(sc)->if_flags & IFF_UP) == 0) {
985 m_freem(m);
986 goto newpack;
987 }
988 if (netisr_queue(NETISR_IP, m)) { /* (0) on success. */
989 SL2IFP(sc)->if_ierrors++;
990 SL2IFP(sc)->if_iqdrops++;
991 }
992 goto newpack;
993 }
994 if (sc->sc_mp < sc->sc_ep) {
995 *sc->sc_mp++ = c;
996 sc->sc_escape = 0;
997 return 0;
998 }
999
1000 /* can't put lower; would miss an extra frame */
1001 sc->sc_flags |= SC_ERROR;
1002
1003 error:
1004 SL2IFP(sc)->if_ierrors++;
1005 newpack:
1006 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
1007 sc->sc_escape = 0;
1008 return 0;
1009 }
1010
1011 /*
1012 * Process an ioctl request.
1013 */
1014 static int
1015 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
1016 {
1017 register struct ifaddr *ifa = (struct ifaddr *)data;
1018 register struct ifreq *ifr = (struct ifreq *)data;
1019 register int s, error = 0;
1020 struct sl_softc *sc = ifp->if_softc;
1021
1022 s = splimp();
1023
1024 switch (cmd) {
1025
1026 case SIOCSIFFLAGS:
1027 /*
1028 * if.c will set the interface up even if we
1029 * don't want it to.
1030 */
1031 if (sc->sc_ttyp == NULL) {
1032 ifp->if_flags &= ~IFF_UP;
1033 }
1034 break;
1035 case SIOCSIFADDR:
1036 /*
1037 * This is "historical" - set the interface up when
1038 * setting the address.
1039 */
1040 if (ifa->ifa_addr->sa_family == AF_INET) {
1041 if (sc->sc_ttyp != NULL)
1042 ifp->if_flags |= IFF_UP;
1043 } else {
1044 error = EAFNOSUPPORT;
1045 }
1046 break;
1047
1048 case SIOCSIFDSTADDR:
1049 if (ifa->ifa_addr->sa_family != AF_INET)
1050 error = EAFNOSUPPORT;
1051 break;
1052
1053 case SIOCADDMULTI:
1054 case SIOCDELMULTI:
1055 break;
1056
1057 case SIOCSIFMTU:
1058 /*
1059 * Set the interface MTU.
1060 */
1061 if (ifr->ifr_mtu > SLTMAX)
1062 error = EINVAL;
1063 else {
1064 struct tty *tp;
1065
1066 ifp->if_mtu = ifr->ifr_mtu;
1067 tp = sc->sc_ttyp;
1068 if (tp != NULL)
1069 clist_alloc_cblocks(&tp->t_outq,
1070 SLIP_HIWAT + 2 * ifp->if_mtu + 1,
1071 SLIP_HIWAT + 2 * ifp->if_mtu + 1);
1072 }
1073 break;
1074
1075 default:
1076 error = EINVAL;
1077 }
1078 splx(s);
1079 return (error);
1080 }
1081
1082 static void
1083 sl_keepalive(void *chan)
1084 {
1085 struct sl_softc *sc = chan;
1086
1087 if (sc->sc_keepalive) {
1088 if (sc->sc_flags & SC_KEEPALIVE) {
1089 if (sc->sc_ttyp->t_pgrp != NULL) {
1090 PGRP_LOCK(sc->sc_ttyp->t_pgrp);
1091 pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
1092 PGRP_UNLOCK(sc->sc_ttyp->t_pgrp);
1093 }
1094 } else
1095 sc->sc_flags |= SC_KEEPALIVE;
1096 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1097 } else {
1098 sc->sc_flags &= ~SC_KEEPALIVE;
1099 }
1100 }
1101
1102 static void
1103 sl_outfill(void *chan)
1104 {
1105 struct sl_softc *sc = chan;
1106 register struct tty *tp = sc->sc_ttyp;
1107 int s;
1108
1109 if (sc->sc_outfill && tp != NULL) {
1110 if (sc->sc_flags & SC_OUTWAIT) {
1111 s = splimp ();
1112 ++SL2IFP(sc)->if_obytes;
1113 (void) putc(FRAME_END, &tp->t_outq);
1114 tt_oproc(tp);
1115 splx (s);
1116 } else
1117 sc->sc_flags |= SC_OUTWAIT;
1118 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1119 } else {
1120 sc->sc_flags &= ~SC_OUTWAIT;
1121 }
1122 }
Cache object: 9c5fe5c4305ae1b85657034f6ffab3e3
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