if_ppp.c

基于组件方式开发操作系统的OSKIT源代码

/*
 * if_ppp.c - Point-to-Point Protocol (PPP) Asynchronous driver.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Drew D. Perkins
 * Carnegie Mellon University
 * 4910 Forbes Ave.
 * Pittsburgh, PA 15213
 * [phone]
 * [e-mail]
 *
 * Based on:
 *	@(#)if_sl.c	7.6.1.2 (Berkeley) 2/15/89
 *
 * Copyright (c) 1987 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Serial Line interface
 *
 * Rick Adams
 * Center for Seismic Studies
 * 1300 N 17th Street, Suite 1450
 * Arlington, Virginia 22209
 * [phone]
 * [e-mail]
 * seismo!rick
 *
 * Pounded on heavily by Chris Torek ([e-mail], umcp-cs!chris).
 * Converted to 4.3BSD Beta by Chris Torek.
 * Other changes made at Berkeley, based in part on code by Kirk Smith.
 *
 * Converted to 4.3BSD+ 386BSD by Brad Parker ([e-mail])
 * Added VJ tcp header compression; more unified ioctls
 *
 * Extensively modified by Paul Mackerras ([e-mail]).
 * Cleaned up a lot of the mbuf-related code to fix bugs that
 * caused system crashes and packet corruption.  Changed pppstart
 * so that it doesn't just give up with a collision if the whole
 * packet doesn't fit in the output ring buffer.
 *
 * Added priority queueing for interactive IP packets, following
 * the model of if_sl.c, plus hooks for bpf.
 * Paul Mackerras ([e-mail]).
 */

/* from if_sl.c,v 1.11 84/10/04 12:54:47 rick Exp */

#include "ppp.h"
#if NPPP > 0

#define VJC

#include <sys/param.h>
#include <sys/systm.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 <sys/vnode.h>
#include <sys/kernel.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>
#endif

#include "bpfilter.h"
#if NBPFILTER > 0
#include <sys/time.h>
#include <net/bpf.h>
#endif

#ifdef VJC
#include <net/pppcompress.h>
#define HDROFF	MAX_HDR
/* HDROFF should really be 128, but other parts of the system will
   panic on TCP+IP headers bigger than MAX_HDR = MHLEN (100). */

#else
#define	HDROFF	(0)
#endif

#include <net/if_ppp.h>
#include <machine/cpu.h>

/* This is a FreeBSD-2.x kernel. */
#define CCOUNT(q)	((q)->c_cc)

#define	PPP_HIWAT	400	/* Don't start a new packet if HIWAT on que */
#define	PPP_MAXMTU	16384	/* Largest MTU we allow */

struct ppp_softc ppp_softc[NPPP];

void	pppattach __P((void));
int	pppopen __P((dev_t dev, struct tty *tp));
int	pppclose __P((struct tty *tp, int flag));
int	pppread __P((struct tty *tp, struct uio *uio, int flag));
int	pppwrite __P((struct tty *tp, struct uio *uio, int flag));
int	ppptioctl __P((struct tty *tp, int cmd, caddr_t data, int flag,
		       struct proc *));
int	pppoutput __P((struct ifnet *, struct mbuf *,
		       struct sockaddr *, struct rtentry *));
int	pppinput __P((int c, struct tty *tp));
int	pppioctl __P((struct ifnet *ifp, int cmd, caddr_t data));
int	pppstart __P((struct tty *tp));

static struct linesw pppdisc = {
	pppopen, pppclose, pppread, pppwrite, ppptioctl,
	pppinput, pppstart, ttymodem
};

extern struct	ppp_softc *pppalloc __P((pid_t pid));
extern void	pppdealloc __P((struct ppp_softc *sc));
extern struct	mbuf *ppp_dequeue __P((struct ppp_softc *sc));
extern int	ppppktin __P((struct ppp_softc *sc, struct mbuf *m, int ilen));

static int	pppasyncstart __P((struct ppp_softc *));
static u_short	pppfcs __P((u_short fcs, u_char *cp, int len));
static int	pppgetm __P((struct ppp_softc *sc));
static struct	mbuf *ppp_btom __P((struct ppp_softc *sc));
static void	pppdumpm __P((struct mbuf *m0, int pktlen));
static void	pppdumpb __P((u_char *b, int l));
static void	ppplogchar __P((struct ppp_softc *, int));

/*
 * Some useful mbuf macros not in mbuf.h.
 */
#define M_DATASTART(m)	\
	((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf : \
	    (m)->m_flags & M_PKTHDR ? (m)->m_pktdat : (m)->m_dat)

#define M_DATASIZE(m)	\
	((m)->m_flags & M_EXT ? (m)->m_ext.ext_size : \
	    (m)->m_flags & M_PKTHDR ? MHLEN: MLEN)

/*
 * 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))

/*
 * Does c need to be escaped?
 */
#define ESCAPE_P(c)	(sc->sc_asyncmap[(c) >> 5] & (1 << ((c) & 0x1F)))

/*
 * Called from boot code to establish ppp interfaces.
 */
void
pppattach()
{
    register struct ppp_softc *sc;
    register int i = 0;

    linesw[PPPDISC] = pppdisc;

    for (sc = ppp_softc; i < NPPP; sc++) {
	sc->sc_if.if_name = "ppp";
	sc->sc_if.if_unit = i++;
	sc->sc_if.if_mtu = PPP_MTU;
	sc->sc_if.if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
	sc->sc_if.if_type = IFT_PPP;
	sc->sc_if.if_hdrlen = PPP_HDRLEN;
	sc->sc_if.if_ioctl = pppioctl;
	sc->sc_if.if_output = pppoutput;
	sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
	sc->sc_inq.ifq_maxlen = IFQ_MAXLEN;
	sc->sc_fastq.ifq_maxlen = IFQ_MAXLEN;
	if_attach(&sc->sc_if);
#if NBPFILTER > 0
	bpfattach(&sc->sc_bpf, &sc->sc_if, DLT_PPP, PPP_HDRLEN);
#endif
    }
}

/*
 * Allocate a ppp interface unit and initialize it.
 */
struct ppp_softc *
pppalloc(pid)
    pid_t pid;
{
    int nppp;
    struct ppp_softc *sc;

    for (nppp = 0, sc = ppp_softc; nppp < NPPP; nppp++, sc++)
	if (sc->sc_xfer == pid) {
	    sc->sc_xfer = 0;
	    break;
	}
    if (nppp >= NPPP)
	for (nppp = 0, sc = ppp_softc; nppp < NPPP; nppp++, sc++)
	    if (sc->sc_devp == NULL)
		break;
    if (nppp >= NPPP)
	return NULL;

    sc->sc_flags = 0;
    sc->sc_mru = PPP_MRU;
#ifdef VJC
    sl_compress_init(&sc->sc_comp);
#endif
    sc->sc_if.if_flags |= IFF_RUNNING;
    microtime(&sc->sc_if.if_lastchange);

    return sc;
}

/*
 * Deallocate a ppp unit.
 */
void
pppdealloc(sc)
	struct ppp_softc *sc;
{
    struct mbuf *m;

    if_down(&sc->sc_if);
    sc->sc_devp = NULL;
    sc->sc_xfer = 0;
    for (;;) {
	IF_DEQUEUE(&sc->sc_inq, m);
	if (m == NULL)
	    break;
	m_freem(m);
    }
    for (;;) {
	IF_DEQUEUE(&sc->sc_fastq, m);
	if (m == NULL)
	    break;
	m_freem(m);
    }
    sc->sc_if.if_flags &= ~(IFF_UP|IFF_RUNNING);
    microtime(&sc->sc_if.if_lastchange);
}

/*
 * Line specific open routine for async tty devices.
 * Attach the given tty to the first available ppp unit.
 */
/* ARGSUSED */
int
pppopen(dev, tp)
    dev_t dev;
    register struct tty *tp;
{
    struct proc *p = curproc;		/* XXX */
    register struct ppp_softc *sc;
    int error, s, i;

    if (error = suser(p->p_ucred, &p->p_acflag))
	return (error);

    if (tp->t_line == PPPDISC) {
	sc = (struct ppp_softc *) tp->t_sc;
	if (sc != NULL && sc->sc_devp == (void *) tp)
	    return (0);
    }

    if ((sc = pppalloc(p->p_pid)) == NULL)
	return ENXIO;

    if (sc->sc_outm != NULL) {
	m_freem(sc->sc_outm);
	sc->sc_outm = NULL;
    }

    if (pppgetm(sc) == 0) {
	sc->sc_if.if_flags &= ~(IFF_UP|IFF_RUNNING);
	microtime(&sc->sc_if.if_lastchange);
	return (ENOBUFS);
    }

    sc->sc_ilen = 0;
    bzero(sc->sc_asyncmap, sizeof(sc->sc_asyncmap));
    sc->sc_asyncmap[0] = 0xffffffff;
    sc->sc_asyncmap[3] = 0x60000000;
    sc->sc_rasyncmap = 0;
    sc->sc_devp = (void *) tp;
    sc->sc_start = pppasyncstart;

    tp->t_sc = (caddr_t) sc;
    ttyflush(tp, FREAD | FWRITE);
    /*
     * XXX we fudge t_canq to avoid providing pppselect() and FIONREAD.
     * I hope one char is enough.  The following actually gives CBSIZE
     * chars.
     */
    clist_alloc_cblocks(&tp->t_canq, 1, 1);
    clist_alloc_cblocks(&tp->t_outq, sc->sc_if.if_mtu + PPP_HIWAT,
			sc->sc_if.if_mtu + PPP_HIWAT);
    clist_alloc_cblocks(&tp->t_rawq, 0, 0);

    return (0);
}

/*
 * Line specific close routine.
 * Detach the tty from the ppp unit.
 * Mimics part of ttyclose().
 */
int
pppclose(tp, flag)
    struct tty *tp;
    int flag;
{
    register struct ppp_softc *sc;
    struct mbuf *m;
    int s;

    ttyflush(tp, FREAD | FWRITE);
    s = splimp();		/* paranoid; splnet probably ok */
    clist_free_cblocks(&tp->t_canq);
    clist_free_cblocks(&tp->t_outq);
    tp->t_line = 0;
    sc = (struct ppp_softc *)tp->t_sc;
    if (sc != NULL) {
	tp->t_sc = NULL;
	if (tp == (struct tty *) sc->sc_devp) {
	    m_freem(sc->sc_outm);
	    sc->sc_outm = NULL;
	    m_freem(sc->sc_m);
	    sc->sc_m = NULL;
	    pppdealloc(sc);
	}
    }
    splx(s);
    return (0);			/* success */
}

/*
 * Line specific (tty) read routine.
 */
int
pppread(tp, uio, flag)
    register struct tty *tp;
    struct uio *uio;
    int flag;
{
    register struct ppp_softc *sc = (struct ppp_softc *)tp->t_sc;
    struct mbuf *m, *m0;
    register int s;
    int error = 0;

    if ((tp->t_state & TS_CONNECTED) == 0)
	return 0;		/* end of file */
    if (sc == NULL || tp != (struct tty *) sc->sc_devp)
	return 0;
    s = splimp();
    while (sc->sc_inq.ifq_head == NULL && tp->t_line == PPPDISC) {
	if (tp->t_state & TS_ASYNC || flag & IO_NDELAY) {
	    splx(s);
	    return (EWOULDBLOCK);
	}
	error = ttysleep(tp, TSA_HUP_OR_INPUT(tp), TTIPRI | PCATCH, "pppin", 0);
	if (error)
	    return error;
    }
    if (tp->t_line != PPPDISC) {
	splx(s);
	return (-1);
    }

    /* Pull place-holder byte out of canonical queue */
    getc(&tp->t_canq);

    /* Get the packet from the input queue */
    IF_DEQUEUE(&sc->sc_inq, m0);
    splx(s);

    for (m = m0; m && uio->uio_resid; m = m->m_next)
	if (error = uiomove(mtod(m, u_char *), m->m_len, uio))
	    break;
    m_freem(m0);
    return (error);
}

/*
 * Line specific (tty) write routine.
 */
int
pppwrite(tp, uio, flag)
    register struct tty *tp;
    struct uio *uio;
    int flag;
{
    register struct ppp_softc *sc = (struct ppp_softc *)tp->t_sc;
    struct mbuf *m, *m0, **mp;
    struct sockaddr dst;
    struct ppp_header *ph1, *ph2;
    int len, error;

    if ((tp->t_state & TS_CONNECTED) == 0)
	return 0;		/* wrote 0 bytes */
    if (tp->t_line != PPPDISC)
	return (EINVAL);
    if (sc == NULL || tp != (struct tty *) sc->sc_devp)
	return EIO;
    if (uio->uio_resid > sc->sc_if.if_mtu + PPP_HDRLEN ||
	uio->uio_resid < PPP_HDRLEN)
	return (EMSGSIZE);
    for (mp = &m0; uio->uio_resid; mp = &m->m_next) {
	MGET(m, M_WAIT, MT_DATA);
	if ((*mp = m) == NULL) {
	    m_freem(m0);
	    return (ENOBUFS);
	}
	m->m_len=0;
	if (uio->uio_resid >= MCLBYTES / 2)
	    MCLGET(m, M_DONTWAIT);
	len = M_TRAILINGSPACE(m);
	if (len > uio->uio_resid)
	    len = uio->uio_resid;
	if (error = uiomove(mtod(m, u_char *), len, uio)) {
	    m_freem(m0);
	    return (error);
	}
	m->m_len = len;
    }
    dst.sa_family = AF_UNSPEC;
    ph1 = (struct ppp_header *) &dst.sa_data;
    ph2 = mtod(m0, struct ppp_header *);
    *ph1 = *ph2;
    m0->m_data += PPP_HDRLEN;
    m0->m_len -= PPP_HDRLEN;
    return (pppoutput(&sc->sc_if, m0, &dst, (struct rtentry *)0));
}

/*
 * Line specific (tty) ioctl routine.
 * Provide a way to get the ppp unit number.
 * This discipline requires that tty device drivers call
 * the line specific l_ioctl routine from their ioctl routines.
 */
/* ARGSUSED */
int
ppptioctl(tp, cmd, data, flag, p)
    struct tty *tp;
    caddr_t data;
    int cmd, flag;
    struct proc *p;
{
    register struct ppp_softc *sc = (struct ppp_softc *) tp->t_sc;
    int s, error, flags, mru;

    if (sc == NULL || tp != (struct tty *) sc->sc_devp)
	return -1;

    switch (cmd) {
    case FIONREAD:
	*(int *)data = sc->sc_inq.ifq_len;
	break;

    case PPPIOCGUNIT:
	*(int *)data = sc->sc_if.if_unit;
	break;

    case PPPIOCGFLAGS:
	*(u_int *)data = sc->sc_flags;
	break;

    case PPPIOCSFLAGS:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	flags = *(int *)data & SC_MASK;
	s = splimp();
	sc->sc_flags = (sc->sc_flags & ~SC_MASK) | flags;
	splx(s);
	break;

    case PPPIOCSASYNCMAP:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	sc->sc_asyncmap[0] = *(u_int *)data;
	break;

    case PPPIOCGASYNCMAP:
	*(u_int *)data = sc->sc_asyncmap[0];
	break;

    case PPPIOCSRASYNCMAP:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	sc->sc_rasyncmap = *(u_int *)data;
	break;

    case PPPIOCGRASYNCMAP:
	*(u_int *)data = sc->sc_rasyncmap;
	break;

    case PPPIOCSXASYNCMAP:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	bcopy(data, sc->sc_asyncmap, sizeof(sc->sc_asyncmap));
	sc->sc_asyncmap[1] = 0;		    /* mustn't escape 0x20 - 0x3f */
	sc->sc_asyncmap[2] &= ~0x40000000;  /* mustn't escape 0x5e */
	sc->sc_asyncmap[3] |= 0x60000000;   /* must escape 0x7d, 0x7e */
	break;

    case PPPIOCGXASYNCMAP:
	bcopy(sc->sc_asyncmap, data, sizeof(sc->sc_asyncmap));
	break;

    case PPPIOCSMRU:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);