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BSD 4_3_Reno release
[unix-history] / usr / src / sys / net / if_sl.c
/*
* Copyright (c) 1987, 1989 Regents of the University of California.
* All rights reserved.
*
* Redistribution is only permitted until one year after the first shipment
* of 4.4BSD by the Regents. Otherwise, redistribution and use in source and
* binary forms are permitted provided that: (1) source distributions retain
* this entire copyright notice and comment, and (2) distributions including
* binaries display the following acknowledgement: This product includes
* software developed by the University of California, Berkeley and its
* contributors'' in the documentation or other materials provided with the
* distribution and in all advertising materials mentioning features or use
* of this software. 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 AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* @(#)if_sl.c 7.21 (Berkeley) 6/28/90
*/
/*
* 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.
*/
/* $Header: if_sl.c,v 1.7 89/05/31 02:24:52 van Exp $ */
/* from if_sl.c,v 1.11 84/10/04 12:54:47 rick Exp */
#include "sl.h"
#if NSL > 0
#include "param.h"
#include "user.h"
#include "mbuf.h"
#include "buf.h"
#include "dkstat.h"
#include "socket.h"
#include "ioctl.h"
#include "file.h"
#include "tty.h"
#include "kernel.h"
#include "conf.h"
#include "errno.h"
#include "if.h"
#include "if_types.h"
#include "netisr.h"
#include "route.h"
#if INET
#include "../netinet/in.h"
#include "../netinet/in_systm.h"
#include "../netinet/in_var.h"
#include "../netinet/ip.h"
#endif
#include "machine/mtpr.h"
#include "slcompress.h"
#include "if_slvar.h"
/*
* 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.
*/
#define BUFOFFSET 128
#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 }
* signals a "soft" exit from slip mode by usermode process
*/
#define ABT_ESC '\033' /* can't be t_intr - distant host must know it*/
#define ABT_WAIT 1 /* in seconds - idle before an escape & after */
#define ABT_RECYCLE (5*2+2) /* in seconds - time window processing abort */
#define ABT_SOFT 3 /* count of escapes */
/*
* The following disgusting hack gets around the problem that IP TOS
* can't be set yet. We want to put "interactive" traffic on a high
* priority queue. To decide if traffic is interactive, we check that
* a) it is TCP and b) one of its ports is telnet, rlogin or ftp control.
*/
static u_short interactive_ports[8] = {
0, 513, 0, 0,
0, 21, 0, 23,
};
#define INTERACTIVE(p) (interactive_ports[(p) & 7] == (p))
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 */
#define t_sc T_LINEP
int sloutput(), slioctl(), ttrstrt();
extern struct timeval time;
/*
* Called from boot code to establish sl interfaces.
*/
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_unit = i++;
sc->sc_if.if_mtu = SLMTU;
sc->sc_if.if_flags = IFF_POINTOPOINT;
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);
}
}
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 */
slopen(dev, tp)
dev_t dev;
register struct tty *tp;
{
register struct sl_softc *sc;
register int nsl;
int error;
if (error = suser(u.u_cred, &u.u_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.
* Mimics part of ttyclose().
*/
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 */
sltioctl(tp, cmd, data, flag)
struct tty *tp;
caddr_t data;
{
struct sl_softc *sc = (struct sl_softc *)tp->t_sc;
int s;
switch (cmd) {
case TIOCGETD: /* XXX */
case SLIOGUNIT:
*(int *)data = sc->sc_if.if_unit;
break;
case SLIOCGFLAGS:
*(int *)data = sc->sc_flags;
break;
case SLIOCSFLAGS:
#define SC_MASK 0xffff
s = splimp();
sc->sc_flags =
(sc->sc_flags &~ SC_MASK) | ((*(int *)data) & SC_MASK);
splx(s);
break;
default:
return (-1);
}
return (0);
}
/*
* Queue a packet. Start transmission if not active.
*/
sloutput(ifp, m, dst)
struct ifnet *ifp;
register struct mbuf *m;
struct sockaddr *dst;
{
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);
return (EAFNOSUPPORT);
}
if (sc->sc_ttyp == NULL) {
m_freem(m);
return (ENETDOWN); /* sort of */
}
if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0) {
m_freem(m);
return (EHOSTUNREACH);
}
ifq = &sc->sc_if.if_snd;
if ((ip = mtod(m, struct ip *))->ip_p == IPPROTO_TCP) {
register int p = ((int *)ip)[ip->ip_hl];
if (INTERACTIVE(p & 0xffff) || INTERACTIVE(p >> 16)) {
ifq = &sc->sc_fastq;
p = 1;
} else
p = 0;
if (sc->sc_flags & SC_COMPRESS) {
/*
* The last parameter turns off connection id
* compression for background traffic: Since
* fastq traffic can jump ahead of the background
* traffic, we don't know what order packets will
* go on the line.
*/
p = sl_compress_tcp(m, ip, &sc->sc_comp, p);
*mtod(m, u_char *) |= p;
}
} else if (sc->sc_flags & SC_NOICMP && ip->ip_p == IPPROTO_ICMP) {
m_freem(m);
return (0);
}
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.
*/
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;
int s;
struct mbuf *m2;
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 == NULL)
IF_DEQUEUE(&sc->sc_if.if_snd, m);
splx(s);
if (m == NULL)
return;
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_bytessent;
(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_bytessent += 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_bytessent += 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_bytessent;
sc->sc_if.if_opackets++;
}
sc->sc_if.if_obytes = sc->sc_bytessent;
}
}
/*
* 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.
*/
slinput(c, tp)
register int c;
register struct tty *tp;
{
register struct sl_softc *sc;
register struct mbuf *m;
register int len;
int s;
tk_nin++;
sc = (struct sl_softc *)tp->t_sc;
if (sc == NULL)
return;
if (!(tp->t_state&TS_CARR_ON)) /* XXX */
return;
++sc->sc_bytesrcvd;
++sc->sc_if.if_ibytes;
c &= 0xff; /* XXX */
#ifdef ABT_ESC
if (sc->sc_flags & SC_ABORT) {
/* if we see an abort after "idle" time, count it */
if (c == ABT_ESC && time.tv_sec >= sc->sc_lasttime + ABT_WAIT) {
sc->sc_abortcount++;
/* record when the first abort escape arrived */
if (sc->sc_abortcount == 1)
sc->sc_starttime = time.tv_sec;
}
/*
* if we have an abort, see that we have not run out of time,
* or that we have an "idle" time after the complete escape
* sequence
*/
if (sc->sc_abortcount) {
if (time.tv_sec >= sc->sc_starttime + ABT_RECYCLE)
sc->sc_abortcount = 0;
if (sc->sc_abortcount >= ABT_SOFT &&
time.tv_sec >= sc->sc_lasttime + ABT_WAIT) {
slclose(tp);
return;
}
}
sc->sc_lasttime = time.tv_sec;
}
#endif
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:
len = sc->sc_mp - sc->sc_buf;
if (len < 3)
/* less than min length packet - ignore */
goto newpack;
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_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_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_flags |= SC_COMPRESS;
} else
goto error;
}
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;
}
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.
*/
slioctl(ifp, cmd, data)
register struct ifnet *ifp;
int cmd;
caddr_t data;
{
register struct ifaddr *ifa = (struct ifaddr *)data;
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;
default:
error = EINVAL;
}
splx(s);
return (error);
}
#endif
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.