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29 * @(#)if_sl.c 8.6 (Berkeley) 2/1/94
34 * Serial Line interface
37 * Center for Seismic Studies
38 * 1300 N 17th Street, Suite 1450
39 * Arlington, Virginia 22209
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.
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.
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.
60 * Note that splimp() is used throughout to block both (tty) input
61 * interrupts and network activity; thus, splimp must be >= spltty.
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/malloc.h>
73 #include <sys/socket.h>
74 #include <sys/sockio.h>
75 #include <sys/fcntl.h>
76 #include <sys/signalvar.h>
78 #include <sys/clist.h>
79 #include <sys/kernel.h>
81 #include <sys/module.h>
85 #include <net/if_types.h>
86 #include <net/netisr.h>
89 #include <netinet/in.h>
90 #include <netinet/in_systm.h>
91 #include <netinet/in_var.h>
92 #include <netinet/ip.h>
94 #error "Huh? Slip without inet?"
97 #include <net/slcompress.h>
98 #include <net/if_slvar.h>
103 static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface");
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
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).
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.
143 #define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
144 #define SLRMAX (MCLBYTES - BUFOFFSET)
145 #define SLBUFSIZE (SLRMAX + BUFOFFSET)
147 #define SLMTU 552 /* default MTU */
149 #define SLTMAX 1500 /* maximum MTU */
150 #define SLIP_HIWAT roundup(50,CBSIZE)
151 #define CLISTRESERVE 1024 /* Can't let clists get too low */
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.
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 */
165 static LIST_HEAD(sl_list, sl_softc) sl_list;
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 */
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 *);
189 static struct linesw slipdisc = {
193 .l_write = l_nowrite,
201 * Called from boot code to establish sl interfaces.
204 sl_modevent(module_t mod, int type, void *data)
208 ldisc_register(SLIPDISC, &slipdisc);
212 ldisc_deregister(SLIPDISC);
213 printf("if_sl module unload - not possible for this module type\n");
221 static moduledata_t sl_mod = {
227 DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
229 static int *st_unit_list;
230 static size_t st_unit_max = 0;
233 slisunitfree(int unit)
237 LIST_FOREACH(sc, &sl_list, sl_next) {
238 if (SL2IFP(sc)->if_dunit == unit)
244 static struct sl_softc *
245 sl_for_tty(struct tty *tp)
249 LIST_FOREACH(nc, &sl_list, sl_next) {
250 if (nc->sc_ttyp == tp)
260 for (i = 0; i < st_unit_max; i++)
261 if (st_unit_list[i] == unit)
267 slmarkstatic(int unit)
271 if (slisstatic(unit))
274 MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT);
279 bcopy(st_unit_list, t, sizeof(int) * st_unit_max);
280 free(st_unit_list, M_SL);
283 st_unit_list[st_unit_max] = unit;
287 static struct sl_softc *
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) {
301 m = m_gethdr(M_TRYWAIT, MT_DATA);
303 MCLGET(m, M_TRYWAIT);
304 if ((m->m_flags & M_EXT) == 0) {
311 printf("sl: can't allocate buffer\n");
316 sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
318 sc->sc_buf = sc->sc_ep - SLRMAX;
319 sc->sc_mp = sc->sc_buf;
320 sl_compress_init(&sc->sc_comp, -1);
322 SL2IFP(sc)->if_softc = sc;
323 SL2IFP(sc)->if_mtu = SLMTU;
324 SL2IFP(sc)->if_flags =
328 IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST | IFF_NEEDSGIANT;
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);
340 * Find a suitable unit number.
342 for (unit=0; ; unit++) {
343 if (slisstatic(unit))
345 if (!slisunitfree(unit))
349 if_initname(SL2IFP(sc), "sl", unit);
350 LIST_INSERT_HEAD(&sl_list, sc, sl_next);
352 if_attach(SL2IFP(sc));
353 bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN);
360 * Line specific open routine.
361 * Attach the given tty to the first available sl unit.
365 slopen(struct cdev *dev, register struct tty *tp)
367 register struct sl_softc *sc;
370 error = priv_check(curthread, PRIV_NET_SLIP);
374 if ((sc = slcreate()) == NULL)
377 tp->t_hotchar = FRAME_END;
379 SL2IFP(sc)->if_baudrate = tp->t_ospeed;
380 ttyflush(tp, FREAD | FWRITE);
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.
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);
405 sldestroy(struct sl_softc *sc)
407 bpfdetach(SL2IFP(sc));
408 if_detach(SL2IFP(sc));
410 LIST_REMOVE(sc, sl_next);
412 mtx_destroy(&sc->sc_fastq.ifq_mtx);
414 free(sc->bpfbuf, M_SL);
419 * Line specific close routine.
420 * Detach the tty from the sl unit.
423 slclose(struct tty *tp, int flag)
425 register struct sl_softc *sc;
428 ttyflush(tp, FREAD | FWRITE);
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.
434 s = splimp(); /* actually, max(spltty, splnet) */
435 clist_free_cblocks(&tp->t_outq);
438 if (sc->sc_outfill) {
440 untimeout(sl_outfill, sc, sc->sc_ofhandle);
442 if (sc->sc_keepalive) {
443 sc->sc_keepalive = 0;
444 untimeout(sl_keepalive, sc, sc->sc_kahandle);
455 * Line specific (tty) ioctl routine.
456 * Provide a way to get the sl unit number.
460 sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag,
463 struct sl_softc *sc = sl_for_tty(tp);
469 *(int *)data = SL2IFP(sc)->if_dunit;
473 unit = *(u_int *)data;
478 if (SL2IFP(sc)->if_dunit != unit) {
479 if (!slisunitfree(unit)) {
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);
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);
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,
510 if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
511 untimeout(sl_keepalive, sc, sc->sc_kahandle);
512 sc->sc_flags &= ~SC_KEEPALIVE;
518 *(int *)data = sc->sc_keepalive / hz;
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,
528 if ((sc->sc_flags & SC_OUTWAIT) != 0) {
529 untimeout(sl_outfill, sc, sc->sc_ofhandle);
530 sc->sc_flags &= ~SC_OUTWAIT;
536 *(int *)data = sc->sc_outfill / hz;
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.
554 sloutput(struct ifnet *ifp, register struct mbuf *m, struct sockaddr *dst,
557 register struct sl_softc *sc = ifp->if_softc;
558 register struct ip *ip;
562 * `Cannot happen' (see slioctl). Someday we will extend
563 * the line protocol to support other address families.
565 if (dst->sa_family != AF_INET) {
566 if_printf(ifp, "af%d not supported\n", dst->sa_family);
568 SL2IFP(sc)->if_noproto++;
569 return (EAFNOSUPPORT);
572 if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
576 if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
578 return (EHOSTUNREACH);
580 ip = mtod(m, struct ip *);
581 if (SL2IFP(sc)->if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
583 return (ENETRESET); /* XXX ? */
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)));
589 IFQ_HANDOFF(SL2IFP(sc), m, error);
591 SL2IFP(sc)->if_oerrors++;
598 slstart(struct ifnet *ifp)
600 struct sl_softc *sc = ifp->if_softc;
604 if (sc->sc_ttyp->t_outq.c_cc == 0)
605 sltstart(sc->sc_ttyp);
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.
615 sltstart(struct tty *tp)
617 register struct sl_softc *sc = sl_for_tty(tp);
618 register struct mbuf *m;
620 register struct ip *ip;
622 register int len = 0;
624 GIANT_REQUIRED; /* tty */
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.
634 if (tp->t_outq.c_cc != 0) {
636 sc->sc_flags &= ~SC_OUTWAIT;
637 if (tp->t_outq.c_cc > SLIP_HIWAT)
642 * This happens briefly when the line shuts down.
648 * Get a packet and send it to the interface.
651 IF_DEQUEUE(&sc->sc_fastq, m);
653 SL2IFP(sc)->if_omcasts++; /* XXX */
655 IF_DEQUEUE(&SL2IFP(sc)->if_snd, m);
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.
666 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
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).
675 register struct mbuf *m1 = m;
678 if (sc->bpfbuf == NULL)
679 MALLOC(sc->bpfbuf, u_char *,
680 SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT);
683 cp = sc->bpfbuf + SLIP_HDRLEN;
686 register int mlen = m1->m_len;
688 bcopy(mtod(m1, caddr_t), cp, mlen);
691 } while ((m1 = m1->m_next) != NULL);
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,
700 if (bpf_peers_present(SL2IFP(sc)->if_bpf) && sc->bpfbuf) {
702 * Put the SLIP pseudo-"link header" in place. The
703 * compressed header is now at the beginning of the
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);
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.
719 if (cfreecount < CLISTRESERVE + SLTMAX) {
721 SL2IFP(sc)->if_collisions++;
725 sc->sc_flags &= ~SC_OUTWAIT;
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.
731 if (tp->t_outq.c_cc == 0) {
732 ++SL2IFP(sc)->if_obytes;
733 (void) putc(FRAME_END, &tp->t_outq);
739 cp = mtod(m, u_char *); ep = cp + m->m_len;
742 * Find out how many bytes in the string we can
743 * handle without doing something special.
745 register u_char *bp = cp;
758 * Put n characters at once
759 * into the tty output queue.
761 if (b_to_q((char *)bp, cp - bp,
764 SL2IFP(sc)->if_obytes += cp - bp;
767 * If there are characters left in the mbuf,
768 * the first one must be special..
769 * Put it out in a different form.
772 if (putc(FRAME_ESCAPE, &tp->t_outq))
774 if (putc(*cp++ == FRAME_ESCAPE ?
775 TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
777 (void) unputc(&tp->t_outq);
780 SL2IFP(sc)->if_obytes += 2;
786 if (putc(FRAME_END, &tp->t_outq)) {
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.
794 (void) unputc(&tp->t_outq);
795 (void) putc(FRAME_END, &tp->t_outq);
796 SL2IFP(sc)->if_collisions++;
798 ++SL2IFP(sc)->if_obytes;
799 SL2IFP(sc)->if_opackets++;
806 * Copy data buffer to mbuf chain; add ifnet pointer.
809 sl_btom(struct sl_softc *sc, register int len)
811 struct mbuf *m, *newm;
813 MGETHDR(m, M_DONTWAIT, MT_DATA);
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.
825 MCLGET(m, M_DONTWAIT);
826 if ((m->m_flags & M_EXT) == 0) {
828 * we couldn't get a cluster - if memory's this
829 * low, it's time to start dropping packets.
834 /* Swap the new and old clusters */
838 sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE;
840 m->m_data = (caddr_t)sc->sc_buf;
842 bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
845 m->m_pkthdr.len = len;
846 m->m_pkthdr.rcvif = SL2IFP(sc);
851 * tty interface receiver interrupt.
854 slinput(int c, struct tty *tp)
856 register struct sl_softc *sc;
857 register struct mbuf *m;
859 u_char chdr[CHDR_LEN];
865 if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
866 sc->sc_flags |= SC_ERROR;
871 ++SL2IFP(sc)->if_ibytes;
873 if (SL2IFP(sc)->if_flags & IFF_DEBUG) {
876 * If we have a previous abort, see whether
877 * this one is within the time limit.
879 if (sc->sc_abortcount &&
880 time_uptime >= sc->sc_starttime + ABT_WINDOW)
881 sc->sc_abortcount = 0;
883 * If we see an abort after "idle" time, count it;
884 * record when the first abort escape arrived.
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) {
895 sc->sc_abortcount = 0;
896 sc->sc_lasttime = time_uptime;
901 case TRANS_FRAME_ESCAPE:
906 case TRANS_FRAME_END:
916 sc->sc_flags &= ~SC_KEEPALIVE;
917 if(sc->sc_flags & SC_ERROR) {
918 sc->sc_flags &= ~SC_ERROR;
921 len = sc->sc_mp - sc->sc_buf;
923 /* less than min length packet - ignore */
926 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
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.
935 bcopy(sc->sc_buf, chdr, CHDR_LEN);
938 if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
940 c = TYPE_COMPRESSED_TCP;
941 else if (c == TYPE_UNCOMPRESSED_TCP)
942 *sc->sc_buf &= 0x4f; /* XXX */
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.
950 if (SL2IFP(sc)->if_flags & SC_COMPRESS) {
951 len = sl_uncompress_tcp(&sc->sc_buf, len,
952 (u_int)c, &sc->sc_comp);
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);
961 SL2IFP(sc)->if_flags |= SC_COMPRESS;
965 if (bpf_peers_present(SL2IFP(sc)->if_bpf)) {
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.
972 register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
974 hp[SLX_DIR] = SLIPDIR_IN;
975 bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
976 BPF_TAP(SL2IFP(sc), hp, len + SLIP_HDRLEN);
978 m = sl_btom(sc, len);
982 SL2IFP(sc)->if_ipackets++;
984 if ((SL2IFP(sc)->if_flags & IFF_UP) == 0) {
988 if (netisr_queue(NETISR_IP, m)) { /* (0) on success. */
989 SL2IFP(sc)->if_ierrors++;
990 SL2IFP(sc)->if_iqdrops++;
994 if (sc->sc_mp < sc->sc_ep) {
1000 /* can't put lower; would miss an extra frame */
1001 sc->sc_flags |= SC_ERROR;
1004 SL2IFP(sc)->if_ierrors++;
1006 sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
1012 * Process an ioctl request.
1015 slioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
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;
1028 * if.c will set the interface up even if we
1031 if (sc->sc_ttyp == NULL) {
1032 ifp->if_flags &= ~IFF_UP;
1037 * This is "historical" - set the interface up when
1038 * setting the address.
1040 if (ifa->ifa_addr->sa_family == AF_INET) {
1041 if (sc->sc_ttyp != NULL)
1042 ifp->if_flags |= IFF_UP;
1044 error = EAFNOSUPPORT;
1048 case SIOCSIFDSTADDR:
1049 if (ifa->ifa_addr->sa_family != AF_INET)
1050 error = EAFNOSUPPORT;
1059 * Set the interface MTU.
1061 if (ifr->ifr_mtu > SLTMAX)
1066 ifp->if_mtu = ifr->ifr_mtu;
1069 clist_alloc_cblocks(&tp->t_outq,
1070 SLIP_HIWAT + 2 * ifp->if_mtu + 1,
1071 SLIP_HIWAT + 2 * ifp->if_mtu + 1);
1083 sl_keepalive(void *chan)
1085 struct sl_softc *sc = chan;
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);
1095 sc->sc_flags |= SC_KEEPALIVE;
1096 sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
1098 sc->sc_flags &= ~SC_KEEPALIVE;
1103 sl_outfill(void *chan)
1105 struct sl_softc *sc = chan;
1106 register struct tty *tp = sc->sc_ttyp;
1109 if (sc->sc_outfill && tp != NULL) {
1110 if (sc->sc_flags & SC_OUTWAIT) {
1112 ++SL2IFP(sc)->if_obytes;
1113 (void) putc(FRAME_END, &tp->t_outq);
1117 sc->sc_flags |= SC_OUTWAIT;
1118 sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
1120 sc->sc_flags &= ~SC_OUTWAIT;