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0dc908e79c
freebsd/sys/net/if_sl.c
Ruslan Ermilov ea26d58729 Replaced the misleading uses of a historical artefact M_TRYWAIT with M_WAIT. 
Removed dead code that assumed that M_TRYWAIT can return NULL; it's not true
since the advent of MBUMA.

Reviewed by:	arch

There are ongoing disputes as to whether we want to switch to directly using
UMA flags M_WAITOK/M_NOWAIT for mbuf(9) allocation.
2008-03-25 09:39:02 +00:00

1111 lines
27 KiB
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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.
* 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
* $FreeBSD$
*/
/*
* 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 "opt_inet.h"
#include "opt_slip.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/fcntl.h>
#include <sys/signalvar.h>
#include <sys/tty.h>
#include <sys/clist.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/netisr.h>
#if INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#else
#error "Huh? Slip without inet?"
#endif
#include <net/slcompress.h>
#include <net/if_slvar.h>
#include <net/slip.h>
#include <net/bpf.h>
static MALLOC_DEFINE(M_SL, "sl", "SLIP Interface");
/*
* SLRMAX 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, SLRMAX can be at most
* MCLBYTES - 128
*
* SLMTU is the default transmit MTU. The transmit MTU should be kept
* small enough so that interactive use doesn't suffer, but large
* enough to provide good performance. 552 is a good choice for SLMTU
* because it is high enough to not fragment TCP packets being routed
* through this host. Packet fragmentation is bad with SLIP because
* fragment headers aren't compressed. The previous assumptions about
* the best MTU value don't really hold when using modern modems with
* BTLZ data compression because the modem buffers play a much larger
* role in interactive performance than the MTU. The MTU can be changed
* at any time to suit the specific environment with ifconfig(8), and
* its maximum value is defined as SLTMAX. SLTMAX must not be so large
* that it would overflow the stack if BPF is configured (XXX; if_ppp.c
* handles this better).
*
* SLIP_HIWAT is 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.
*/
#define BUFOFFSET (128+sizeof(struct ifnet **)+SLIP_HDRLEN)
#define SLRMAX (MCLBYTES - BUFOFFSET)
#define SLBUFSIZE (SLRMAX + BUFOFFSET)
#ifndef SLMTU
#define SLMTU 552 /* default MTU */
#endif
#define SLTMAX 1500 /* maximum MTU */
#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 */
static LIST_HEAD(sl_list, sl_softc) sl_list;
#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 */
static int slisstatic(int);
static void slmarkstatic(int);
static struct sl_softc *slcreate(void);
static void sldestroy(struct sl_softc *sc);
static struct mbuf *sl_btom(struct sl_softc *, int);
static timeout_t sl_keepalive;
static timeout_t sl_outfill;
static l_close_t slclose;
static l_rint_t slinput;
static l_ioctl_t sltioctl;
static l_start_t sltstart;
static int slioctl(struct ifnet *, u_long, caddr_t);
static int slopen(struct cdev *, struct tty *);
static int sloutput(struct ifnet *,
struct mbuf *, struct sockaddr *, struct rtentry *);
static void slstart(struct ifnet *);
static struct linesw slipdisc = {
.l_open = slopen,
.l_close = slclose,
.l_read = l_noread,
.l_write = l_nowrite,
.l_ioctl = sltioctl,
.l_rint = slinput,
.l_start = sltstart,
.l_modem = ttymodem
};
/*
* Called from boot code to establish sl interfaces.
*/
static int
sl_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
ldisc_register(SLIPDISC, &slipdisc);
LIST_INIT(&sl_list);
break;
case MOD_UNLOAD:
ldisc_deregister(SLIPDISC);
printf("if_sl module unload - not possible for this module type\n");
return EINVAL;
default:
return EOPNOTSUPP;
}
return 0;
}
static moduledata_t sl_mod = {
"if_sl",
sl_modevent,
0
};
DECLARE_MODULE(if_sl, sl_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
static int *st_unit_list;
static size_t st_unit_max = 0;
static int
slisunitfree(int unit)
{
struct sl_softc *sc;
LIST_FOREACH(sc, &sl_list, sl_next) {
if (SL2IFP(sc)->if_dunit == unit)
return (0);
}
return (1);
}
static struct sl_softc *
sl_for_tty(struct tty *tp)
{
struct sl_softc *nc;
LIST_FOREACH(nc, &sl_list, sl_next) {
if (nc->sc_ttyp == tp)
return (nc);
}
return (NULL);
}
static int
slisstatic(int unit)
{
size_t i;
for (i = 0; i < st_unit_max; i++)
if (st_unit_list[i] == unit)
return 1;
return 0;
}
static void
slmarkstatic(int unit)
{
int *t;
if (slisstatic(unit))
return;
MALLOC(t, int *, sizeof(int) * (st_unit_max+1), M_SL, M_NOWAIT);
if (t == NULL)
return;
if (st_unit_list) {
bcopy(st_unit_list, t, sizeof(int) * st_unit_max);
free(st_unit_list, M_SL);
}
st_unit_list = t;
st_unit_list[st_unit_max] = unit;
st_unit_max++;
}
static struct sl_softc *
slcreate(void)
{
struct sl_softc *sc;
int unit;
struct mbuf *m;
MALLOC(sc, struct sl_softc *, sizeof(*sc), M_SL, M_WAITOK | M_ZERO);
sc->sc_ifp = if_alloc(IFT_SLIP);
if (sc->sc_ifp == NULL) {
free(sc, M_SL);
return (NULL);
}
m = m_gethdr(M_WAIT, MT_DATA);
MCLGET(m, M_WAIT);
sc->sc_ep = mtod(m, u_char *) + SLBUFSIZE;
sc->sc_mbuf = m;
sc->sc_buf = sc->sc_ep - SLRMAX;
sc->sc_mp = sc->sc_buf;
sl_compress_init(&sc->sc_comp, -1);
SL2IFP(sc)->if_softc = sc;
SL2IFP(sc)->if_mtu = SLMTU;
SL2IFP(sc)->if_flags =
#ifdef SLIP_IFF_OPTS
SLIP_IFF_OPTS;
#else
IFF_POINTOPOINT | SC_AUTOCOMP | IFF_MULTICAST | IFF_NEEDSGIANT;
#endif
SL2IFP(sc)->if_ioctl = slioctl;
SL2IFP(sc)->if_output = sloutput;
SL2IFP(sc)->if_start = slstart;
SL2IFP(sc)->if_snd.ifq_maxlen = 50;
sc->sc_fastq.ifq_maxlen = 32;
SL2IFP(sc)->if_linkmib = sc;
SL2IFP(sc)->if_linkmiblen = sizeof *sc;
mtx_init(&sc->sc_fastq.ifq_mtx, "sl_fastq", NULL, MTX_DEF);
/*
* Find a suitable unit number.
*/
for (unit=0; ; unit++) {
if (slisstatic(unit))
continue;
if (!slisunitfree(unit))
continue;
break;
}
if_initname(SL2IFP(sc), "sl", unit);
LIST_INSERT_HEAD(&sl_list, sc, sl_next);
if_attach(SL2IFP(sc));
bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN);
return sc;
}
/*
* Line specific open routine.
* Attach the given tty to the first available sl unit.
*/
/* ARGSUSED */
static int
slopen(struct cdev *dev, register struct tty *tp)
{
register struct sl_softc *sc;
int s, error;
error = priv_check(curthread, PRIV_NET_SLIP);
if (error)
return (error);
if ((sc = slcreate()) == NULL)
return (ENOBUFS);
tp->t_hotchar = FRAME_END;
sc->sc_ttyp = tp;
SL2IFP(sc)->if_baudrate = tp->t_ospeed;
ttyflush(tp, FREAD | FWRITE);
/*
* We don't use t_canq or t_rawq, so reduce their
* cblock resources to 0. Reserve enough cblocks
* for t_outq to guarantee that we can fit a full
* packet if the SLIP_HIWAT check allows slstart()
* to loop. Use the same value for the cblock
* limit since the reserved blocks should always
* be enough. Reserving cblocks probably makes
* the CLISTRESERVE check unnecessary and wasteful.
*/
clist_alloc_cblocks(&tp->t_canq, 0, 0);
clist_alloc_cblocks(&tp->t_outq,
SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1,
SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1);
clist_alloc_cblocks(&tp->t_rawq, 0, 0);
s = splnet();
if_up(SL2IFP(sc));
splx(s);
return (0);
}
static void
sldestroy(struct sl_softc *sc)
{
bpfdetach(SL2IFP(sc));
if_detach(SL2IFP(sc));
if_free(SL2IFP(sc));
LIST_REMOVE(sc, sl_next);
m_free(sc->sc_mbuf);
mtx_destroy(&sc->sc_fastq.ifq_mtx);
if (sc->bpfbuf)
free(sc->bpfbuf, M_SL);
free(sc, M_SL);
}
/*
* Line specific close routine.
* Detach the tty from the sl unit.
*/
static int
slclose(struct tty *tp, int flag)
{
register struct sl_softc *sc;
int s;
ttyflush(tp, FREAD | FWRITE);
/*
* XXX the placement of the following spl is misleading. tty
* interrupts must be blocked across line discipline switches
* and throughout closes to avoid races.
*/
s = splimp(); /* actually, max(spltty, splnet) */
clist_free_cblocks(&tp->t_outq);
sc = sl_for_tty(tp);
if (sc != NULL) {
if (sc->sc_outfill) {
sc->sc_outfill = 0;
untimeout(sl_outfill, sc, sc->sc_ofhandle);
}
if (sc->sc_keepalive) {
sc->sc_keepalive = 0;
untimeout(sl_keepalive, sc, sc->sc_kahandle);
}
if_down(SL2IFP(sc));
sc->sc_ttyp = NULL;
sldestroy(sc);
}
splx(s);
return 0;
}
/*
* Line specific (tty) ioctl routine.
* Provide a way to get the sl unit number.
*/
/* ARGSUSED */
static int
sltioctl(struct tty *tp, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct sl_softc *sc = sl_for_tty(tp);
int s, unit, wasup;
s = splimp();
switch (cmd) {
case SLIOCGUNIT:
*(int *)data = SL2IFP(sc)->if_dunit;
break;
case SLIOCSUNIT:
unit = *(u_int *)data;
if (unit < 0) {
splx(s);
return (ENXIO);
}
if (SL2IFP(sc)->if_dunit != unit) {
if (!slisunitfree(unit)) {
splx(s);
return (ENXIO);
}
wasup = SL2IFP(sc)->if_flags & IFF_UP;
bpfdetach(SL2IFP(sc));
if_detach(SL2IFP(sc));
LIST_REMOVE(sc, sl_next);
if_initname(SL2IFP(sc), "sl", unit);
LIST_INSERT_HEAD(&sl_list, sc, sl_next);
if_attach(SL2IFP(sc));
bpfattach(SL2IFP(sc), DLT_SLIP, SLIP_HDRLEN);
if (wasup)
if_up(SL2IFP(sc));
else
if_down(SL2IFP(sc));
clist_alloc_cblocks(&tp->t_outq,
SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1,
SLIP_HIWAT + 2 * SL2IFP(sc)->if_mtu + 1);
}
slmarkstatic(unit);
break;
case SLIOCSKEEPAL:
sc->sc_keepalive = *(u_int *)data * hz;
if (sc->sc_keepalive) {
sc->sc_flags |= SC_KEEPALIVE;
sc->sc_kahandle = timeout(sl_keepalive, sc,
sc->sc_keepalive);
} else {
if ((sc->sc_flags & SC_KEEPALIVE) != 0) {
untimeout(sl_keepalive, sc, sc->sc_kahandle);
sc->sc_flags &= ~SC_KEEPALIVE;
}
}
break;
case SLIOCGKEEPAL:
*(int *)data = sc->sc_keepalive / hz;
break;
case SLIOCSOUTFILL:
sc->sc_outfill = *(u_int *)data * hz;
if (sc->sc_outfill) {
sc->sc_flags |= SC_OUTWAIT;
sc->sc_ofhandle = timeout(sl_outfill, sc,
sc->sc_outfill);
} else {
if ((sc->sc_flags & SC_OUTWAIT) != 0) {
untimeout(sl_outfill, sc, sc->sc_ofhandle);
sc->sc_flags &= ~SC_OUTWAIT;
}
}
break;
case SLIOCGOUTFILL:
*(int *)data = sc->sc_outfill / hz;
break;
default:
splx(s);
return (ENOIOCTL);
}
splx(s);
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.
*/
static int
sloutput(struct ifnet *ifp, register struct mbuf *m, struct sockaddr *dst,
struct rtentry *rtp)
{
register struct sl_softc *sc = ifp->if_softc;
register struct ip *ip;
int error;
/*
* `Cannot happen' (see slioctl). Someday we will extend
* the line protocol to support other address families.
*/
if (dst->sa_family != AF_INET) {
if_printf(ifp, "af%d not supported\n", dst->sa_family);
m_freem(m);
SL2IFP(sc)->if_noproto++;
return (EAFNOSUPPORT);
}
if (sc->sc_ttyp == NULL || !(ifp->if_flags & IFF_UP)) {
m_freem(m);
return (ENETDOWN);
}
if ((sc->sc_ttyp->t_state & TS_CONNECTED) == 0) {
m_freem(m);
return (EHOSTUNREACH);
}
ip = mtod(m, struct ip *);
if (SL2IFP(sc)->if_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
m_freem(m);
return (ENETRESET); /* XXX ? */
}
if (ip->ip_tos & IPTOS_LOWDELAY &&
!ALTQ_IS_ENABLED(&SL2IFP(sc)->if_snd))
error = !(IF_HANDOFF(&sc->sc_fastq, m, SL2IFP(sc)));
else
IFQ_HANDOFF(SL2IFP(sc), m, error);
if (error) {
SL2IFP(sc)->if_oerrors++;
return (ENOBUFS);
}
return (0);
}
static void
slstart(struct ifnet *ifp)
{
struct sl_softc *sc = ifp->if_softc;
int s;
s = splimp();
if (sc->sc_ttyp->t_outq.c_cc == 0)
sltstart(sc->sc_ttyp);
splx(s);
}
/*
* Start output on interface. Get another datagram
* to send from the interface queue and map it to
* the interface before starting output.
*/
static int
sltstart(struct tty *tp)
{
register struct sl_softc *sc = sl_for_tty(tp);
register struct mbuf *m;
register u_char *cp;
register struct ip *ip;
int s;
register int len = 0;
GIANT_REQUIRED; /* tty */
for (;;) {
/*
* Call output process whether or not there is more in the
* output queue. We are being called in lieu of ttstart
* and must do what it would.
*/
tt_oproc(tp);
if (tp->t_outq.c_cc != 0) {
if (sc != NULL)
sc->sc_flags &= ~SC_OUTWAIT;
if (tp->t_outq.c_cc > SLIP_HIWAT)
return 0;
}
/*
* This happens briefly when the line shuts down.
*/
if (sc == NULL)
return 0;
/*
* Get a packet and send it to the interface.
*/
s = splimp();
IF_DEQUEUE(&sc->sc_fastq, m);
if (m)
SL2IFP(sc)->if_omcasts++; /* XXX */
else
IF_DEQUEUE(&SL2IFP(sc)->if_snd, m);
splx(s);
if (m == NULL)
return 0;
/*
* 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 (bpf_peers_present(SL2IFP(sc)->if_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;
if (sc->bpfbuf == NULL)
MALLOC(sc->bpfbuf, u_char *,
SLTMAX + SLIP_HDRLEN, M_SL, M_NOWAIT);
if (sc->bpfbuf) {
cp = sc->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) != NULL);
}
}
ip = mtod(m, struct ip *);
if (ip->ip_v == IPVERSION && ip->ip_p == IPPROTO_TCP) {
if (SL2IFP(sc)->if_flags & SC_COMPRESS)
*mtod(m, u_char *) |= sl_compress_tcp(m, ip,
&sc->sc_comp, 1);
}
if (bpf_peers_present(SL2IFP(sc)->if_bpf) && sc->bpfbuf) {
/*
* Put the SLIP pseudo-"link header" in place. The
* compressed header is now at the beginning of the
* mbuf.
*/
sc->bpfbuf[SLX_DIR] = SLIPDIR_OUT;
bcopy(mtod(m, caddr_t), &sc->bpfbuf[SLX_CHDR], CHDR_LEN);
BPF_TAP(SL2IFP(sc), sc->bpfbuf, len + SLIP_HDRLEN);
}
/*
* If system is getting low on clists, just flush our
* output queue (if the stuff was important, it'll get
* retransmitted). Note that SLTMAX is used instead of
* the current if_mtu setting because connections that
* have already been established still use the original
* (possibly larger) mss.
*/
if (cfreecount < CLISTRESERVE + SLTMAX) {
m_freem(m);
SL2IFP(sc)->if_collisions++;
continue;
}
sc->sc_flags &= ~SC_OUTWAIT;
/*
* 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) {
++SL2IFP(sc)->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;
SL2IFP(sc)->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;
}
SL2IFP(sc)->if_obytes += 2;
}
}
m = m_free(m);
}
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);
SL2IFP(sc)->if_collisions++;
} else {
++SL2IFP(sc)->if_obytes;
SL2IFP(sc)->if_opackets++;
}
}
return 0;
}
/*
* Copy data buffer to mbuf chain; add ifnet pointer.
*/
static struct mbuf *
sl_btom(struct sl_softc *sc, register int len)
{
struct mbuf *m, *newm;
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);
}
/* Swap the new and old clusters */
newm = m;
m = sc->sc_mbuf;
sc->sc_mbuf = newm;
sc->sc_ep = mtod(newm, u_char *) + SLBUFSIZE;
m->m_data = (caddr_t)sc->sc_buf;
} 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 = SL2IFP(sc);
return (m);
}
/*
* tty interface receiver interrupt.
*/
static int
slinput(int c, struct tty *tp)
{
register struct sl_softc *sc;
register struct mbuf *m;
register int len;
u_char chdr[CHDR_LEN];
tk_nin++;
sc = sl_for_tty(tp);
if (sc == NULL)
return 0;
if (c & TTY_ERRORMASK || (tp->t_state & TS_CONNECTED) == 0) {
sc->sc_flags |= SC_ERROR;
return 0;
}
c &= TTY_CHARMASK;
++SL2IFP(sc)->if_ibytes;
if (SL2IFP(sc)->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_uptime >= 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_uptime >= sc->sc_lasttime + ABT_IDLE) {
if (++sc->sc_abortcount == 1)
sc->sc_starttime = time_uptime;
if (sc->sc_abortcount >= ABT_COUNT) {
slclose(tp,0);
return 0;
}
}
} else
sc->sc_abortcount = 0;
sc->sc_lasttime = time_uptime;
}
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 0;
case FRAME_END:
sc->sc_flags &= ~SC_KEEPALIVE;
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 (bpf_peers_present(SL2IFP(sc)->if_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);
}
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 (SL2IFP(sc)->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 ((SL2IFP(sc)->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;
SL2IFP(sc)->if_flags |= SC_COMPRESS;
} else
goto error;
}
if (bpf_peers_present(SL2IFP(sc)->if_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(SL2IFP(sc), hp, len + SLIP_HDRLEN);
}
m = sl_btom(sc, len);
if (m == NULL)
goto error;
SL2IFP(sc)->if_ipackets++;
if ((SL2IFP(sc)->if_flags & IFF_UP) == 0) {
m_freem(m);
goto newpack;
}
if (netisr_queue(NETISR_IP, m)) { /* (0) on success. */
SL2IFP(sc)->if_ierrors++;
SL2IFP(sc)->if_iqdrops++;
}
goto newpack;
}
if (sc->sc_mp < sc->sc_ep) {
*sc->sc_mp++ = c;
sc->sc_escape = 0;
return 0;
}
/* can't put lower; would miss an extra frame */
sc->sc_flags |= SC_ERROR;
error:
SL2IFP(sc)->if_ierrors++;
newpack:
sc->sc_mp = sc->sc_buf = sc->sc_ep - SLRMAX;
sc->sc_escape = 0;
return 0;
}
/*
* Process an ioctl request.
*/
static int
slioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
register struct ifaddr *ifa = (struct ifaddr *)data;
register struct ifreq *ifr = (struct ifreq *)data;
register int s, error = 0;
struct sl_softc *sc = ifp->if_softc;
s = splimp();
switch (cmd) {
case SIOCSIFFLAGS:
/*
* if.c will set the interface up even if we
* don't want it to.
*/
if (sc->sc_ttyp == NULL) {
ifp->if_flags &= ~IFF_UP;
}
break;
case SIOCSIFADDR:
/*
* This is "historical" - set the interface up when
* setting the address.
*/
if (ifa->ifa_addr->sa_family == AF_INET) {
if (sc->sc_ttyp != NULL)
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:
break;
case SIOCSIFMTU:
/*
* Set the interface MTU.
*/
if (ifr->ifr_mtu > SLTMAX)
error = EINVAL;
else {
struct tty *tp;
ifp->if_mtu = ifr->ifr_mtu;
tp = sc->sc_ttyp;
if (tp != NULL)
clist_alloc_cblocks(&tp->t_outq,
SLIP_HIWAT + 2 * ifp->if_mtu + 1,
SLIP_HIWAT + 2 * ifp->if_mtu + 1);
}
break;
default:
error = EINVAL;
}
splx(s);
return (error);
}
static void
sl_keepalive(void *chan)
{
struct sl_softc *sc = chan;
if (sc->sc_keepalive) {
if (sc->sc_flags & SC_KEEPALIVE) {
if (sc->sc_ttyp->t_pgrp != NULL) {
PGRP_LOCK(sc->sc_ttyp->t_pgrp);
pgsignal (sc->sc_ttyp->t_pgrp, SIGURG, 1);
PGRP_UNLOCK(sc->sc_ttyp->t_pgrp);
}
} else
sc->sc_flags |= SC_KEEPALIVE;
sc->sc_kahandle = timeout(sl_keepalive, sc, sc->sc_keepalive);
} else {
sc->sc_flags &= ~SC_KEEPALIVE;
}
}
static void
sl_outfill(void *chan)
{
struct sl_softc *sc = chan;
register struct tty *tp = sc->sc_ttyp;
int s;
if (sc->sc_outfill && tp != NULL) {
if (sc->sc_flags & SC_OUTWAIT) {
s = splimp ();
++SL2IFP(sc)->if_obytes;
(void) putc(FRAME_END, &tp->t_outq);
tt_oproc(tp);
splx (s);
} else
sc->sc_flags |= SC_OUTWAIT;
sc->sc_ofhandle = timeout(sl_outfill, sc, sc->sc_outfill);
} else {
sc->sc_flags &= ~SC_OUTWAIT;
}
}
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