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diff --git a/sys/net/if_sl.c b/sys/net/if_sl.c
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+/*
+ * Copyright (c) 1987, 1989, 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)if_sl.c 8.6 (Berkeley) 2/1/94
+ */
+
+/*
+ * Serial Line interface
+ *
+ * Rick Adams
+ * Center for Seismic Studies
+ * 1300 N 17th Street, Suite 1450
+ * Arlington, Virginia 22209
+ * (703)276-7900
+ * rick@seismo.ARPA
+ * seismo!rick
+ *
+ * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris).
+ * N.B.: this belongs in netinet, not net, the way it stands now.
+ * Should have a link-layer type designation, but wouldn't be
+ * backwards-compatible.
+ *
+ * Converted to 4.3BSD Beta by Chris Torek.
+ * Other changes made at Berkeley, based in part on code by Kirk Smith.
+ * W. Jolitz added slip abort.
+ *
+ * Hacked almost beyond recognition by Van Jacobson (van@helios.ee.lbl.gov).
+ * Added priority queuing for "interactive" traffic; hooks for TCP
+ * header compression; ICMP filtering (at 2400 baud, some cretin
+ * pinging you can use up all your bandwidth). Made low clist behavior
+ * more robust and slightly less likely to hang serial line.
+ * Sped up a bunch of things.
+ *
+ * Note that splimp() is used throughout to block both (tty) input
+ * interrupts and network activity; thus, splimp must be >= spltty.
+ */
+
+#include "sl.h"
+#if NSL > 0
+
+#include "bpfilter.h"
+
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/mbuf.h>
+#include <sys/buf.h>
+#include <sys/dkstat.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/file.h>
+#include <sys/tty.h>
+#include <sys/kernel.h>
+#include <sys/conf.h>
+
+#include <machine/cpu.h>
+
+#include <net/if.h>
+#include <net/if_types.h>
+#include <net/netisr.h>
+#include <net/route.h>
+
+#if INET
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#else
+Huh? Slip without inet?
+#endif
+
+#include <net/slcompress.h>
+#include <net/if_slvar.h>
+#include <net/slip.h>
+
+#if NBPFILTER > 0
+#include <sys/time.h>
+#include <net/bpf.h>
+#endif
+
+/*
+ * SLMAX is a hard limit on input packet size. To simplify the code
+ * and improve performance, we require that packets fit in an mbuf
+ * cluster, and if we get a compressed packet, there's enough extra
+ * room to expand the header into a max length tcp/ip header (128
+ * bytes). So, SLMAX can be at most
+ * MCLBYTES - 128
+ *
+ * SLMTU is a hard limit on output packet size. To insure good
+ * interactive response, SLMTU wants to be the smallest size that
+ * amortizes the header cost. (Remember that even with
+ * type-of-service queuing, we have to wait for any in-progress
+ * packet to finish. I.e., we wait, on the average, 1/2 * mtu /
+ * cps, where cps is the line speed in characters per second.
+ * E.g., 533ms wait for a 1024 byte MTU on a 9600 baud line. The
+ * average compressed header size is 6-8 bytes so any MTU > 90
+ * bytes will give us 90% of the line bandwidth. A 100ms wait is
+ * tolerable (500ms is not), so want an MTU around 296. (Since TCP
+ * will send 256 byte segments (to allow for 40 byte headers), the
+ * typical packet size on the wire will be around 260 bytes). In
+ * 4.3tahoe+ systems, we can set an MTU in a route so we do that &
+ * leave the interface MTU relatively high (so we don't IP fragment
+ * when acting as a gateway to someone using a stupid MTU).
+ *
+ * Similar considerations apply to SLIP_HIWAT: It's the amount of
+ * data that will be queued 'downstream' of us (i.e., in clists
+ * waiting to be picked up by the tty output interrupt). If we
+ * queue a lot of data downstream, it's immune to our t.o.s. queuing.
+ * E.g., if SLIP_HIWAT is 1024, the interactive traffic in mixed
+ * telnet/ftp will see a 1 sec wait, independent of the mtu (the
+ * wait is dependent on the ftp window size but that's typically
+ * 1k - 4k). So, we want SLIP_HIWAT just big enough to amortize
+ * the cost (in idle time on the wire) of the tty driver running
+ * off the end of its clists & having to call back slstart for a
+ * new packet. For a tty interface with any buffering at all, this
+ * cost will be zero. Even with a totally brain dead interface (like
+ * the one on a typical workstation), the cost will be <= 1 character
+ * time. So, setting SLIP_HIWAT to ~100 guarantees that we'll lose
+ * at most 1% while maintaining good interactive response.
+ */
+#if NBPFILTER > 0
+#define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
+#else
+#define BUFOFFSET (128+sizeof(struct ifnet **))
+#endif
+#define SLMAX (MCLBYTES - BUFOFFSET)
+#define SLBUFSIZE (SLMAX + BUFOFFSET)
+#define SLMTU 296
+#define SLIP_HIWAT roundup(50,CBSIZE)
+#define CLISTRESERVE 1024 /* Can't let clists get too low */
+
+/*
+ * SLIP ABORT ESCAPE MECHANISM:
+ * (inspired by HAYES modem escape arrangement)
+ * 1sec escape 1sec escape 1sec escape { 1sec escape 1sec escape }
+ * within window time signals a "soft" exit from slip mode by remote end
+ * if the IFF_DEBUG flag is on.
+ */
+#define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/
+#define ABT_IDLE 1 /* in seconds - idle before an escape */
+#define ABT_COUNT 3 /* count of escapes for abort */
+#define ABT_WINDOW (ABT_COUNT*2+2) /* in seconds - time to count */
+
+struct sl_softc sl_softc[NSL];
+
+#define FRAME_END 0xc0 /* Frame End */
+#define FRAME_ESCAPE 0xdb /* Frame Esc */
+#define TRANS_FRAME_END 0xdc /* transposed frame end */
+#define TRANS_FRAME_ESCAPE 0xdd /* transposed frame esc */
+
+extern struct timeval time;
+
+static int slinit __P((struct sl_softc *));
+static struct mbuf *sl_btom __P((struct sl_softc *, int));
+
+/*
+ * Called from boot code to establish sl interfaces.
+ */
+void
+slattach()
+{
+ register struct sl_softc *sc;
+ register int i = 0;
+
+ for (sc = sl_softc; i < NSL; sc++) {
+ sc->sc_if.if_name = "sl";
+ sc->sc_if.if_next = NULL;
+ sc->sc_if.if_unit = i++;
+ sc->sc_if.if_mtu = SLMTU;
+ sc->sc_if.if_flags =
+ IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST;
+ sc->sc_if.if_type = IFT_SLIP;
+ sc->sc_if.if_ioctl = slioctl;
+ sc->sc_if.if_output = sloutput;
+ sc->sc_if.if_snd.ifq_maxlen = 50;
+ sc->sc_fastq.ifq_maxlen = 32;
+ if_attach(&sc->sc_if);
+#if NBPFILTER > 0
+ bpfattach(&sc->sc_bpf, &sc->sc_if, DLT_SLIP, SLIP_HDRLEN);
+#endif
+ }
+}
+
+static int
+slinit(sc)
+ register struct sl_softc *sc;
+{
+ register caddr_t p;
+
+ if (sc->sc_ep == (u_char *) 0) {
+ MCLALLOC(p, M_WAIT);
+ if (p)
+ sc->sc_ep = (u_char *)p + SLBUFSIZE;
+ else {
+ printf("sl%d: can't allocate buffer\n", sc - sl_softc);
+ sc->sc_if.if_flags &= ~IFF_UP;
+ return (0);
+ }
+ }
+ sc->sc_buf = sc->sc_ep - SLMAX;
+ sc->sc_mp = sc->sc_buf;
+ sl_compress_init(&sc->sc_comp);
+ return (1);
+}
+
+/*
+ * Line specific open routine.
+ * Attach the given tty to the first available sl unit.
+ */
+/* ARGSUSED */
+int
+slopen(dev, tp)
+ dev_t dev;
+ register struct tty *tp;
+{
+ struct proc *p = curproc; /* XXX */
+ register struct sl_softc *sc;
+ register int nsl;
+ int error;
+
+ if (error = suser(p->p_ucred, &p->p_acflag))
+ return (error);
+
+ if (tp->t_line == SLIPDISC)
+ return (0);
+
+ for (nsl = NSL, sc = sl_softc; --nsl >= 0; sc++)
+ if (sc->sc_ttyp == NULL) {
+ if (slinit(sc) == 0)
+ return (ENOBUFS);
+ tp->t_sc = (caddr_t)sc;
+ sc->sc_ttyp = tp;
+ sc->sc_if.if_baudrate = tp->t_ospeed;
+ ttyflush(tp, FREAD | FWRITE);
+ return (0);
+ }
+ return (ENXIO);
+}
+
+/*
+ * Line specific close routine.
+ * Detach the tty from the sl unit.
+ */
+void
+slclose(tp)
+ struct tty *tp;
+{
+ register struct sl_softc *sc;
+ int s;
+
+ ttywflush(tp);
+ s = splimp(); /* actually, max(spltty, splnet) */
+ tp->t_line = 0;
+ sc = (struct sl_softc *)tp->t_sc;
+ if (sc != NULL) {
+ if_down(&sc->sc_if);
+ sc->sc_ttyp = NULL;
+ tp->t_sc = NULL;
+ MCLFREE((caddr_t)(sc->sc_ep - SLBUFSIZE));
+ sc->sc_ep = 0;
+ sc->sc_mp = 0;
+ sc->sc_buf = 0;
+ }
+ splx(s);
+}
+
+/*
+ * Line specific (tty) ioctl routine.
+ * Provide a way to get the sl unit number.
+ */
+/* ARGSUSED */
+int
+sltioctl(tp, cmd, data, flag)
+ struct tty *tp;
+ int cmd;
+ caddr_t data;
+ int flag;
+{
+ struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
+
+ switch (cmd) {
+ case SLIOCGUNIT:
+ *(int *)data = sc->sc_if.if_unit;
+ break;
+
+ default:
+ return (-1);
+ }
+ return (0);
+}
+
+/*
+ * Queue a packet. Start transmission if not active.
+ * Compression happens in slstart; if we do it here, IP TOS
+ * will cause us to not compress "background" packets, because
+ * ordering gets trashed. It can be done for all packets in slstart.
+ */
+int
+sloutput(ifp, m, dst, rtp)
+ struct ifnet *ifp;
+ register struct mbuf *m;
+ struct sockaddr *dst;
+ struct rtentry *rtp;
+{
+ register struct sl_softc *sc = &sl_softc[ifp->if_unit];
+ register struct ip *ip;
+ register struct ifqueue *ifq;
+ int s;
+
+ /*
+ * `Cannot happen' (see slioctl). Someday we will extend
+ * the line protocol to support other address families.
+ */
+ if (dst->sa_family != AF_INET) {
+ printf("sl%d: af%d not supported\n", sc->sc_if.if_unit,
+ dst->sa_family);
+ m_freem(m);
+ sc->sc_if.if_noproto++;
+ return (EAFNOSUPPORT);
+ }
+
+ if (sc->sc_ttyp == NULL) {
+ m_freem(m);
+ return (ENETDOWN); /* sort of */
+ }
+ if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 &&
+ (sc->sc_ttyp->t_cflag & CLOCAL) == 0) {
+ m_freem(m);
+ return (EHOSTUNREACH);
+ }
+ ifq = &sc->sc_if.if_snd;
+ ip = mtod(m, struct ip *);
+ if (sc->sc_if.if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
+ m_freem(m);
+ return (ENETRESET); /* XXX ? */
+ }
+ if (ip->ip_tos & IPTOS_LOWDELAY)
+ ifq = &sc->sc_fastq;
+ s = splimp();
+ if (IF_QFULL(ifq)) {
+ IF_DROP(ifq);
+ m_freem(m);
+ splx(s);
+ sc->sc_if.if_oerrors++;
+ return (ENOBUFS);
+ }
+ IF_ENQUEUE(ifq, m);
+ sc->sc_if.if_lastchange = time;
+ if (sc->sc_ttyp->t_outq.c_cc == 0)
+ slstart(sc->sc_ttyp);
+ splx(s);
+ return (0);
+}
+
+/*
+ * Start output on interface. Get another datagram
+ * to send from the interface queue and map it to
+ * the interface before starting output.
+ */
+void
+slstart(tp)
+ register struct tty *tp;
+{
+ register struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
+ register struct mbuf *m;
+ register u_char *cp;
+ register struct ip *ip;
+ int s;
+ struct mbuf *m2;
+#if NBPFILTER > 0
+ u_char bpfbuf[SLMTU + SLIP_HDRLEN];
+ register int len;
+#endif
+ extern int cfreecount;
+
+ for (;;) {
+ /*
+ * If there is more in the output queue, just send it now.
+ * We are being called in lieu of ttstart and must do what
+ * it would.
+ */
+ if (tp->t_outq.c_cc != 0) {
+ (*tp->t_oproc)(tp);
+ if (tp->t_outq.c_cc > SLIP_HIWAT)
+ return;
+ }
+ /*
+ * This happens briefly when the line shuts down.
+ */
+ if (sc == NULL)
+ return;
+
+ /*
+ * Get a packet and send it to the interface.
+ */
+ s = splimp();
+ IF_DEQUEUE(&sc->sc_fastq, m);
+ if (m)
+ sc->sc_if.if_omcasts++; /* XXX */
+ else
+ IF_DEQUEUE(&sc->sc_if.if_snd, m);
+ splx(s);
+ if (m == NULL)
+ return;
+
+ /*
+ * We do the header compression here rather than in sloutput
+ * because the packets will be out of order if we are using TOS
+ * queueing, and the connection id compression will get
+ * munged when this happens.
+ */
+#if NBPFILTER > 0
+ if (sc->sc_bpf) {
+ /*
+ * We need to save the TCP/IP header before it's
+ * compressed. To avoid complicated code, we just
+ * copy the entire packet into a stack buffer (since
+ * this is a serial line, packets should be short
+ * and/or the copy should be negligible cost compared
+ * to the packet transmission time).
+ */
+ register struct mbuf *m1 = m;
+ register u_char *cp = bpfbuf + SLIP_HDRLEN;
+
+ len = 0;
+ do {
+ register int mlen = m1->m_len;
+
+ bcopy(mtod(m1, caddr_t), cp, mlen);
+ cp += mlen;
+ len += mlen;
+ } while (m1 = m1->m_next);
+ }
+#endif
+ if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
+ if (sc->sc_if.if_flags & SC_COMPRESS)
+ *mtod(m, u_char *) |= sl_compress_tcp(m, ip,
+ &sc->sc_comp, 1);
+ }
+#if NBPFILTER > 0
+ if (sc->sc_bpf) {
+ /*
+ * Put the SLIP pseudo-"link header" in place. The
+ * compressed header is now at the beginning of the
+ * mbuf.
+ */
+ bpfbuf[SLX_DIR] = SLIPDIR_OUT;
+ bcopy(mtod(m, caddr_t), &bpfbuf[SLX_CHDR], CHDR_LEN);
+ bpf_tap(sc->sc_bpf, bpfbuf, len + SLIP_HDRLEN);
+ }
+#endif
+ sc->sc_if.if_lastchange = time;
+
+ /*
+ * If system is getting low on clists, just flush our
+ * output queue (if the stuff was important, it'll get
+ * retransmitted).
+ */
+ if (cfreecount < CLISTRESERVE + SLMTU) {
+ m_freem(m);
+ sc->sc_if.if_collisions++;
+ continue;
+ }
+ /*
+ * The extra FRAME_END will start up a new packet, and thus
+ * will flush any accumulated garbage. We do this whenever
+ * the line may have been idle for some time.
+ */
+ if (tp->t_outq.c_cc == 0) {
+ ++sc->sc_if.if_obytes;
+ (void) putc(FRAME_END, &tp->t_outq);
+ }
+
+ while (m) {
+ register u_char *ep;
+
+ cp = mtod(m, u_char *); ep = cp + m->m_len;
+ while (cp < ep) {
+ /*
+ * Find out how many bytes in the string we can
+ * handle without doing something special.
+ */
+ register u_char *bp = cp;
+
+ while (cp < ep) {
+ switch (*cp++) {
+ case FRAME_ESCAPE:
+ case FRAME_END:
+ --cp;
+ goto out;
+ }
+ }
+ out:
+ if (cp > bp) {
+ /*
+ * Put n characters at once
+ * into the tty output queue.
+ */
+ if (b_to_q((char *)bp, cp - bp,
+ &tp->t_outq))
+ break;
+ sc->sc_if.if_obytes += cp - bp;
+ }
+ /*
+ * If there are characters left in the mbuf,
+ * the first one must be special..
+ * Put it out in a different form.
+ */
+ if (cp < ep) {
+ if (putc(FRAME_ESCAPE, &tp->t_outq))
+ break;
+ if (putc(*cp++ == FRAME_ESCAPE ?
+ TRANS_FRAME_ESCAPE : TRANS_FRAME_END,
+ &tp->t_outq)) {
+ (void) unputc(&tp->t_outq);
+ break;
+ }
+ sc->sc_if.if_obytes += 2;
+ }
+ }
+ MFREE(m, m2);
+ m = m2;
+ }
+
+ if (putc(FRAME_END, &tp->t_outq)) {
+ /*
+ * Not enough room. Remove a char to make room
+ * and end the packet normally.
+ * If you get many collisions (more than one or two
+ * a day) you probably do not have enough clists
+ * and you should increase "nclist" in param.c.
+ */
+ (void) unputc(&tp->t_outq);
+ (void) putc(FRAME_END, &tp->t_outq);
+ sc->sc_if.if_collisions++;
+ } else {
+ ++sc->sc_if.if_obytes;
+ sc->sc_if.if_opackets++;
+ }
+ }
+}
+
+/*
+ * Copy data buffer to mbuf chain; add ifnet pointer.
+ */
+static struct mbuf *
+sl_btom(sc, len)
+ register struct sl_softc *sc;
+ register int len;
+{
+ register struct mbuf *m;
+
+ MGETHDR(m, M_DONTWAIT, MT_DATA);
+ if (m == NULL)
+ return (NULL);
+
+ /*
+ * If we have more than MHLEN bytes, it's cheaper to
+ * queue the cluster we just filled & allocate a new one
+ * for the input buffer. Otherwise, fill the mbuf we
+ * allocated above. Note that code in the input routine
+ * guarantees that packet will fit in a cluster.
+ */
+ if (len >= MHLEN) {
+ MCLGET(m, M_DONTWAIT);
+ if ((m->m_flags & M_EXT) == 0) {
+ /*
+ * we couldn't get a cluster - if memory's this
+ * low, it's time to start dropping packets.
+ */
+ (void) m_free(m);
+ return (NULL);
+ }
+ sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
+ m->m_data = (caddr_t)sc->sc_buf;
+ m->m_ext.ext_buf = (caddr_t)((int)sc->sc_buf &~ MCLOFSET);
+ } else
+ bcopy((caddr_t)sc->sc_buf, mtod(m, caddr_t), len);
+
+ m->m_len = len;
+ m->m_pkthdr.len = len;
+ m->m_pkthdr.rcvif = &sc->sc_if;
+ return (m);
+}
+
+/*
+ * tty interface receiver interrupt.
+ */
+void
+slinput(c, tp)
+ register int c;
+ register struct tty *tp;
+{
+ register struct sl_softc *sc;
+ register struct mbuf *m;
+ register int len;
+ int s;
+#if NBPFILTER > 0
+ u_char chdr[CHDR_LEN];
+#endif
+
+ tk_nin++;
+ sc = (struct sl_softc *)tp->t_sc;
+ if (sc == NULL)
+ return;
+ if (c & TTY_ERRORMASK || ((tp->t_state & TS_CARR_ON) == 0 &&
+ (tp->t_cflag & CLOCAL) == 0)) {
+ sc->sc_flags |= SC_ERROR;
+ return;
+ }
+ c &= TTY_CHARMASK;
+
+ ++sc->sc_if.if_ibytes;
+
+ if (sc->sc_if.if_flags & IFF_DEBUG) {
+ if (c == ABT_ESC) {
+ /*
+ * If we have a previous abort, see whether
+ * this one is within the time limit.
+ */
+ if (sc->sc_abortcount &&
+ time.tv_sec >= sc->sc_starttime + ABT_WINDOW)
+ sc->sc_abortcount = 0;
+ /*
+ * If we see an abort after "idle" time, count it;
+ * record when the first abort escape arrived.
+ */
+ if (time.tv_sec >= sc->sc_lasttime + ABT_IDLE) {
+ if (++sc->sc_abortcount == 1)
+ sc->sc_starttime = time.tv_sec;
+ if (sc->sc_abortcount >= ABT_COUNT) {
+ slclose(tp);
+ return;
+ }
+ }
+ } else
+ sc->sc_abortcount = 0;
+ sc->sc_lasttime = time.tv_sec;
+ }
+
+ switch (c) {
+
+ case TRANS_FRAME_ESCAPE:
+ if (sc->sc_escape)
+ c = FRAME_ESCAPE;
+ break;
+
+ case TRANS_FRAME_END:
+ if (sc->sc_escape)
+ c = FRAME_END;
+ break;
+
+ case FRAME_ESCAPE:
+ sc->sc_escape = 1;
+ return;
+
+ case FRAME_END:
+ if(sc->sc_flags & SC_ERROR) {
+ sc->sc_flags &= ~SC_ERROR;
+ goto newpack;
+ }
+ len = sc->sc_mp - sc->sc_buf;
+ if (len < 3)
+ /* less than min length packet - ignore */
+ goto newpack;
+
+#if NBPFILTER > 0
+ if (sc->sc_bpf) {
+ /*
+ * Save the compressed header, so we
+ * can tack it on later. Note that we
+ * will end up copying garbage in some
+ * cases but this is okay. We remember
+ * where the buffer started so we can
+ * compute the new header length.
+ */
+ bcopy(sc->sc_buf, chdr, CHDR_LEN);
+ }
+#endif
+
+ if ((c = (*sc->sc_buf & 0xf0)) != (IPVERSION << 4)) {
+ if (c & 0x80)
+ c = TYPE_COMPRESSED_TCP;
+ else if (c == TYPE_UNCOMPRESSED_TCP)
+ *sc->sc_buf &= 0x4f; /* XXX */
+ /*
+ * We've got something that's not an IP packet.
+ * If compression is enabled, try to decompress it.
+ * Otherwise, if `auto-enable' compression is on and
+ * it's a reasonable packet, decompress it and then
+ * enable compression. Otherwise, drop it.
+ */
+ if (sc->sc_if.if_flags & SC_COMPRESS) {
+ len = sl_uncompress_tcp(&sc->sc_buf, len,
+ (u_int)c, &sc->sc_comp);
+ if (len <= 0)
+ goto error;
+ } else if ((sc->sc_if.if_flags & SC_AUTOCOMP) &&
+ c == TYPE_UNCOMPRESSED_TCP && len >= 40) {
+ len = sl_uncompress_tcp(&sc->sc_buf, len,
+ (u_int)c, &sc->sc_comp);
+ if (len <= 0)
+ goto error;
+ sc->sc_if.if_flags |= SC_COMPRESS;
+ } else
+ goto error;
+ }
+#if NBPFILTER > 0
+ if (sc->sc_bpf) {
+ /*
+ * Put the SLIP pseudo-"link header" in place.
+ * We couldn't do this any earlier since
+ * decompression probably moved the buffer
+ * pointer. Then, invoke BPF.
+ */
+ register u_char *hp = sc->sc_buf - SLIP_HDRLEN;
+
+ hp[SLX_DIR] = SLIPDIR_IN;
+ bcopy(chdr, &hp[SLX_CHDR], CHDR_LEN);
+ bpf_tap(sc->sc_bpf, hp, len + SLIP_HDRLEN);
+ }
+#endif
+ m = sl_btom(sc, len);
+ if (m == NULL)
+ goto error;
+
+ sc->sc_if.if_ipackets++;
+ sc->sc_if.if_lastchange = time;
+ s = splimp();
+ if (IF_QFULL(&ipintrq)) {
+ IF_DROP(&ipintrq);
+ sc->sc_if.if_ierrors++;
+ sc->sc_if.if_iqdrops++;
+ m_freem(m);
+ } else {
+ IF_ENQUEUE(&ipintrq, m);
+ schednetisr(NETISR_IP);
+ }
+ splx(s);
+ goto newpack;
+ }
+ if (sc->sc_mp < sc->sc_ep) {
+ *sc->sc_mp++ = c;
+ sc->sc_escape = 0;
+ return;
+ }
+
+ /* can't put lower; would miss an extra frame */
+ sc->sc_flags |= SC_ERROR;
+
+error:
+ sc->sc_if.if_ierrors++;
+newpack:
+ sc->sc_mp = sc->sc_buf = sc->sc_ep - SLMAX;
+ sc->sc_escape = 0;
+}
+
+/*
+ * Process an ioctl request.
+ */
+int
+slioctl(ifp, cmd, data)
+ register struct ifnet *ifp;
+ int cmd;
+ caddr_t data;
+{
+ register struct ifaddr *ifa = (struct ifaddr *)data;
+ register struct ifreq *ifr;
+ register int s = splimp(), error = 0;
+
+ switch (cmd) {
+
+ case SIOCSIFADDR:
+ if (ifa->ifa_addr->sa_family == AF_INET)
+ ifp->if_flags |= IFF_UP;
+ else
+ error = EAFNOSUPPORT;
+ break;
+
+ case SIOCSIFDSTADDR:
+ if (ifa->ifa_addr->sa_family != AF_INET)
+ error = EAFNOSUPPORT;
+ break;
+
+ case SIOCADDMULTI:
+ case SIOCDELMULTI:
+ ifr = (struct ifreq *)data;
+ if (ifr == 0) {
+ error = EAFNOSUPPORT; /* XXX */
+ break;
+ }
+ switch (ifr->ifr_addr.sa_family) {
+
+#ifdef INET
+ case AF_INET:
+ break;
+#endif
+
+ default:
+ error = EAFNOSUPPORT;
+ break;
+ }
+ break;
+
+ default:
+ error = EINVAL;
+ }
+ splx(s);
+ return (error);
+}
+#endif
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