if_ppp.c

基于组件方式开发操作系统的OSKIT源代码

	mru = *(int *)data;
	if (mru >= PPP_MRU && mru <= PPP_MAXMRU) {
	    sc->sc_mru = mru;
	    if (pppgetm(sc) == 0) {
		error = ENOBUFS;
		sc->sc_mru = PPP_MRU;
		if (pppgetm(sc) == 0)
		{
		    sc->sc_if.if_flags &= ~IFF_UP;
		    microtime(&sc->sc_if.if_lastchange);
		}
	    }
	}
	break;

    case PPPIOCGMRU:
	*(int *)data = sc->sc_mru;
	break;

#ifdef VJC
    case PPPIOCSMAXCID:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	sl_compress_setup(&sc->sc_comp, *(int *)data);
	break;
#endif

    case PPPIOCXFERUNIT:
	if (error = suser(p->p_ucred, &p->p_acflag))
	    return (error);
	sc->sc_xfer = p->p_pid;
	break;

    default:
	return (-1);
    }
    return (0);
}

/*
 * FCS lookup table as calculated by genfcstab.
 */
static u_short fcstab[256] = {
	0x0000,	0x1189,	0x2312,	0x329b,	0x4624,	0x57ad,	0x6536,	0x74bf,
	0x8c48,	0x9dc1,	0xaf5a,	0xbed3,	0xca6c,	0xdbe5,	0xe97e,	0xf8f7,
	0x1081,	0x0108,	0x3393,	0x221a,	0x56a5,	0x472c,	0x75b7,	0x643e,
	0x9cc9,	0x8d40,	0xbfdb,	0xae52,	0xdaed,	0xcb64,	0xf9ff,	0xe876,
	0x2102,	0x308b,	0x0210,	0x1399,	0x6726,	0x76af,	0x4434,	0x55bd,
	0xad4a,	0xbcc3,	0x8e58,	0x9fd1,	0xeb6e,	0xfae7,	0xc87c,	0xd9f5,
	0x3183,	0x200a,	0x1291,	0x0318,	0x77a7,	0x662e,	0x54b5,	0x453c,
	0xbdcb,	0xac42,	0x9ed9,	0x8f50,	0xfbef,	0xea66,	0xd8fd,	0xc974,
	0x4204,	0x538d,	0x6116,	0x709f,	0x0420,	0x15a9,	0x2732,	0x36bb,
	0xce4c,	0xdfc5,	0xed5e,	0xfcd7,	0x8868,	0x99e1,	0xab7a,	0xbaf3,
	0x5285,	0x430c,	0x7197,	0x601e,	0x14a1,	0x0528,	0x37b3,	0x263a,
	0xdecd,	0xcf44,	0xfddf,	0xec56,	0x98e9,	0x8960,	0xbbfb,	0xaa72,
	0x6306,	0x728f,	0x4014,	0x519d,	0x2522,	0x34ab,	0x0630,	0x17b9,
	0xef4e,	0xfec7,	0xcc5c,	0xddd5,	0xa96a,	0xb8e3,	0x8a78,	0x9bf1,
	0x7387,	0x620e,	0x5095,	0x411c,	0x35a3,	0x242a,	0x16b1,	0x0738,
	0xffcf,	0xee46,	0xdcdd,	0xcd54,	0xb9eb,	0xa862,	0x9af9,	0x8b70,
	0x8408,	0x9581,	0xa71a,	0xb693,	0xc22c,	0xd3a5,	0xe13e,	0xf0b7,
	0x0840,	0x19c9,	0x2b52,	0x3adb,	0x4e64,	0x5fed,	0x6d76,	0x7cff,
	0x9489,	0x8500,	0xb79b,	0xa612,	0xd2ad,	0xc324,	0xf1bf,	0xe036,
	0x18c1,	0x0948,	0x3bd3,	0x2a5a,	0x5ee5,	0x4f6c,	0x7df7,	0x6c7e,
	0xa50a,	0xb483,	0x8618,	0x9791,	0xe32e,	0xf2a7,	0xc03c,	0xd1b5,
	0x2942,	0x38cb,	0x0a50,	0x1bd9,	0x6f66,	0x7eef,	0x4c74,	0x5dfd,
	0xb58b,	0xa402,	0x9699,	0x8710,	0xf3af,	0xe226,	0xd0bd,	0xc134,
	0x39c3,	0x284a,	0x1ad1,	0x0b58,	0x7fe7,	0x6e6e,	0x5cf5,	0x4d7c,
	0xc60c,	0xd785,	0xe51e,	0xf497,	0x8028,	0x91a1,	0xa33a,	0xb2b3,
	0x4a44,	0x5bcd,	0x6956,	0x78df,	0x0c60,	0x1de9,	0x2f72,	0x3efb,
	0xd68d,	0xc704,	0xf59f,	0xe416,	0x90a9,	0x8120,	0xb3bb,	0xa232,
	0x5ac5,	0x4b4c,	0x79d7,	0x685e,	0x1ce1,	0x0d68,	0x3ff3,	0x2e7a,
	0xe70e,	0xf687,	0xc41c,	0xd595,	0xa12a,	0xb0a3,	0x8238,	0x93b1,
	0x6b46,	0x7acf,	0x4854,	0x59dd,	0x2d62,	0x3ceb,	0x0e70,	0x1ff9,
	0xf78f,	0xe606,	0xd49d,	0xc514,	0xb1ab,	0xa022,	0x92b9,	0x8330,
	0x7bc7,	0x6a4e,	0x58d5,	0x495c,	0x3de3,	0x2c6a,	0x1ef1,	0x0f78
};

/*
 * Calculate a new FCS given the current FCS and the new data.
 */
static u_short
pppfcs(fcs, cp, len)
    register u_short fcs;
    register u_char *cp;
    register int len;
{
    while (len--)
	fcs = PPP_FCS(fcs, *cp++);
    return (fcs);
}

/*
 * Queue a packet.  Start transmission if not active.
 * Packet is placed in Information field of PPP frame.
 */
int
pppoutput(ifp, m0, dst, rt)
	struct ifnet *ifp;
	struct mbuf *m0;
	struct sockaddr *dst;
	struct rtentry *rt;
{
    register struct ppp_softc *sc = &ppp_softc[ifp->if_unit];
    struct ppp_header *ph;
    int protocol, address, control;
    u_char *cp;
    int s, error;
    struct ip *ip;
    struct ifqueue *ifq;

    if (sc->sc_devp == NULL || (ifp->if_flags & IFF_RUNNING) == 0
	|| (ifp->if_flags & IFF_UP) == 0 && dst->sa_family != AF_UNSPEC) {
	error = ENETDOWN;	/* sort of */
	goto bad;
    }

    /*
     * Compute PPP header.
     */
    address = PPP_ALLSTATIONS;
    control = PPP_UI;
    ifq = &ifp->if_snd;
    switch (dst->sa_family) {
#ifdef INET
    case AF_INET:
	protocol = PPP_IP;
	if ((sc->sc_flags & SC_ENABLE_IP) == 0) {
	    error = ENETDOWN;
	    goto bad;
	}

	/*
	 * If this is a TCP packet to or from an "interactive" port,
	 * put the packet on the fastq instead.
	 */
	if ((ip = mtod(m0, struct ip *))->ip_p == IPPROTO_TCP) {
	    register int p = ntohl(((int *)ip)[ip->ip_hl]);
	    if (INTERACTIVE(p & 0xffff) || INTERACTIVE(p >> 16))
		ifq = &sc->sc_fastq;
	}

      /*
       * Most high-priority services set IPTOS_LOWDELAY.  This is a much more
       * generic mechanism than specific port numbers.  This same mechanism
       * is used by slip.
       */
      if (ip->ip_tos & IPTOS_LOWDELAY)
          ifq = &sc->sc_fastq;

	break;
#endif
#ifdef NS
    case AF_NS:
	protocol = PPP_XNS;
	break;
#endif
    case AF_UNSPEC:
	ph = (struct ppp_header *) dst->sa_data;
	address = ph->ph_address;
	control = ph->ph_control;
	protocol = ntohs(ph->ph_protocol);
	break;
    default:
	printf("ppp%d: af%d not supported\n", ifp->if_unit, dst->sa_family);
	error = EAFNOSUPPORT;
	goto bad;
    }

    /*
     * Add PPP header.  If no space in first mbuf, allocate another.
     * (This assumes M_LEADINGSPACE is always 0 for a cluster mbuf.)
     */
    if (M_LEADINGSPACE(m0) < PPP_HDRLEN) {
	m0 = m_prepend(m0, PPP_HDRLEN, M_DONTWAIT);
	if (m0 == 0) {
	    error = ENOBUFS;
	    goto bad;
	}
	m0->m_len = 0;
    } else
	m0->m_data -= PPP_HDRLEN;

    cp = mtod(m0, u_char *);
    *cp++ = address;
    *cp++ = control;
    *cp++ = protocol >> 8;
    *cp++ = protocol & 0xff;
    m0->m_len += PPP_HDRLEN;

    if (sc->sc_flags & SC_LOG_OUTPKT) {
	printf("ppp%d output: ", ifp->if_unit);
	pppdumpm(m0, -1);
    }

#if NBPFILTER > 0
    /* See if bpf wants to look at the packet. */
    if (sc->sc_bpf)
	bpf_mtap(sc->sc_bpf, m0);
#endif

    /*
     * Put the packet on the appropriate queue.
     */
    s = splimp();
    if (IF_QFULL(ifq)) {
	IF_DROP(ifq);
	splx(s);
	sc->sc_if.if_oerrors++;
	error = ENOBUFS;
	goto bad;
    }
    IF_ENQUEUE(ifq, m0);

    /*
     * Tell the device to send it out.
     */
    (*sc->sc_start)(sc);

    splx(s);
    return (0);

bad:
    m_freem(m0);
    return (error);
}

/*
 * Grab another packet off a queue and apply VJ compression,
 * address/control and/or protocol compression if appropriate.
 */
struct mbuf *
ppp_dequeue(sc)
    struct ppp_softc *sc;
{
    int s;
    struct mbuf *m;
    u_char *cp;
    int address, control, protocol;

    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 NULL;

    /*
     * Extract the ppp header of the new packet.
     * The ppp header will be in one mbuf.
     */
    cp = mtod(m, u_char *);
    address = cp[0];
    control = cp[1];
    protocol = (cp[2] << 8) + cp[3];

#ifdef VJC
    /*
     * If the packet is a TCP/IP packet, see if we can compress it.
     */
    if (protocol == PPP_IP && sc->sc_flags & SC_COMP_TCP) {
	struct ip *ip;
	int type;
	struct mbuf *mp;

	mp = m;
	ip = (struct ip *) (cp + PPP_HDRLEN);
	if (mp->m_len <= PPP_HDRLEN) {
	    mp = mp->m_next;
	    ip = mtod(mp, struct ip *);
	}
	/* this code assumes the IP/TCP header is in one non-shared mbuf */
	if (ip->ip_p == IPPROTO_TCP) {
	    type = sl_compress_tcp(mp, ip, &sc->sc_comp,
				   !(sc->sc_flags & SC_NO_TCP_CCID));
	    switch (type) {
	    case TYPE_UNCOMPRESSED_TCP:
		protocol = PPP_VJC_UNCOMP;
		break;
	    case TYPE_COMPRESSED_TCP:
		protocol = PPP_VJC_COMP;
		cp = mtod(m, u_char *);
		cp[0] = address;	/* header has moved */
		cp[1] = control;
		cp[2] = 0;
		break;
	    }
	    cp[3] = protocol;	/* update protocol in PPP header */
	}
    }
#endif	/* VJC */

#ifdef BSD_COMP
    if (protocol < PPP_COMP && (sc->sc_flags & SC_BSD_COMP)) {
	slen = m_totallen(m0);
	clen = pf_bsd_comp(sc->sc_bsd_db, cbuf, proto, m0, slen);
    }
#endif	/* BSD_COMP */

    /*
     * Compress the address/control and protocol, if possible.
     */
    if (sc->sc_flags & SC_COMP_AC && address == PPP_ALLSTATIONS &&
	control == PPP_UI && protocol != PPP_ALLSTATIONS &&
	protocol != PPP_LCP) {
	/* can compress address/control */
	m->m_data += 2;
	m->m_len -= 2;
    }
    if (sc->sc_flags & SC_COMP_PROT && protocol < 0xFF) {
	/* can compress protocol */
	if (mtod(m, u_char *) == cp) {
	    cp[2] = cp[1];	/* move address/control up */
	    cp[1] = cp[0];
	}
	++m->m_data;
	--m->m_len;
    }

    return m;
}

/*
 * This gets called from pppoutput when a new packet is
 * put on a queue.
 */
static int
pppasyncstart(sc)
    register struct ppp_softc *sc;
{
    register struct tty *tp = (struct tty *) sc->sc_devp;

    pppstart(tp);
    return 0;
}

/*
 * Start output on async tty interface.  Get another datagram
 * to send from the interface queue and start sending it.
 */
int
pppstart(tp)
    register struct tty *tp;
{
    register struct ppp_softc *sc = (struct ppp_softc *) tp->t_sc;
    register struct mbuf *m;
    register int len;
    register u_char *start, *stop, *cp;
    int n, s, ndone, done;
    struct mbuf *m2;

    if ((tp->t_state & TS_CONNECTED) == 0) {
	/* sorry, I can't talk now */
	return 0;
    }
    if (sc == NULL || tp != (struct tty *) sc->sc_devp) {
	(*tp->t_oproc)(tp);
	return 0;
    }

    for (;;) {
	/*
	 * Call output process whether or not there is any output.
	 * We are being called in lieu of ttstart and must do what
	 * it would.
	 */
	if (tp->t_oproc != NULL) {
	    (*tp->t_oproc)(tp);
	    if (CCOUNT(&tp->t_outq) > PPP_HIWAT)
		return 0;
	}

	/*
	 * See if we have an existing packet partly sent.
	 * If not, get a new packet and start sending it.
	 * We take packets on the priority queue ahead of those
	 * on the normal queue.
	 */
	m = sc->sc_outm;
	if (m == NULL) {
	    /*
	     * Get another packet to be sent
	     */
	    m = ppp_dequeue(sc);
	    if (m == NULL)
		return 0;

	    /*
	     * The extra PPP_FLAG 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 (CCOUNT(&tp->t_outq) == 0) {
		++sc->sc_bytessent;
		(void) putc(PPP_FLAG, &tp->t_outq);
	    }

	    /* Calculate the FCS for the first mbuf's worth. */
	    sc->sc_outfcs = pppfcs(PPP_INITFCS, mtod(m, u_char *), m->m_len);
	}

	for (;;) {
	    start = mtod(m, u_char *);
	    len = m->m_len;
	    stop = start + len;
	    while (len > 0) {
		/*
		 * Find out how many bytes in the string we can
		 * handle without doing something special.
		 */
		for (cp = start; cp < stop; cp++)
		    if (ESCAPE_P(*cp))
			break;
		n = cp - start;
		if (n) {
		    /* NetBSD (0.9 or later), 4.3-Reno or similar. */
		    ndone = n - b_to_q(start, n, &tp->t_outq);
		    len -= ndone;
		    start += ndone;
		    sc->sc_bytessent += ndone;

		    if (ndone < n)
			break;	/* packet doesn't fit */
		}
		/*
		 * If there are characters left in the mbuf,
		 * the first one must be special..
		 * Put it out in a different form.
		 */
		if (len) {
		    if (putc(PPP_ESCAPE, &tp->t_outq))
			break;
		    if (putc(*start ^ PPP_TRANS, &tp->t_outq)) {
			(void) unputc(&tp->t_outq);
			break;
		    }
		    sc->sc_bytessent += 2;
		    start++;
		    len--;
		}
	    }
	    /*
	     * If we didn't empty this mbuf, remember where we're up to.
	     * If we emptied the last mbuf, try to add the FCS and closing
	     * flag, and if we can't, leave sc_outm pointing to m, but with
	     * m->m_len == 0, to remind us to output the FCS and flag later.
	     */
	    done = len == 0;
	    if (done && m->m_next == NULL) {
		u_char *p, *q;
		int c;
		u_char endseq[8];

		/*
		 * We may have to escape the bytes in the FCS.
		 */
		p = endseq;
		c = ~sc->sc_outfcs & 0xFF;
		if (ESCAPE_P(c)) {
		    *p++ = PPP_ESCAPE;
		    *p++ = c ^ PPP_TRANS;
		} else
		    *p++ = c;
		c = (~sc->sc_outfcs >> 8) & 0xFF;
		if (ESCAPE_P(c)) {
		    *p++ = PPP_ESCAPE;
		    *p++ = c ^ PPP_TRANS;
		} else
		    *p++ = c;
		*p++ = PPP_FLAG;

		/*
		 * Try to output the FCS and flag.  If the bytes
		 * don't all fit, back out.
		 */
		for (q = endseq; q < p; ++q)
		    if (putc(*q, &tp->t_outq)) {
			done = 0;
			for (; q > endseq; --q)
			    unputc(&tp->t_outq);
			break;
		    }
	    }

	    if (!done) {
		m->m_data = start;
		m->m_len = len;
		sc->sc_outm = m;
		if (tp->t_oproc != NULL)
		    (*tp->t_oproc)(tp);
		return 0;	/* can't do any more at the moment */
	    }

	    /* Finished with this mbuf; free it and move on. */
	    MFREE(m, m2);
	    if (m2 == NULL)
		break;

	    m = m2;
	    sc->sc_outfcs = pppfcs(sc->sc_outfcs, mtod(m, u_char *), m->m_len);
	}

	/* Finished a packet */
	sc->sc_outm = NULL;
	sc->sc_bytessent++;	/* account for closing flag */
	sc->sc_if.if_opackets++;
	sc->sc_if.if_obytes = sc->sc_bytessent;
    }
    return 0;
}

/*
 * Allocate enough mbuf to handle current MRU.
 */
static int
pppgetm(sc)
    register struct ppp_softc *sc;
{
    struct mbuf *m, **mp;
    int len = HDROFF + sc->sc_mru + PPP_HDRLEN + PPP_FCSLEN;
    int s;

    s = splimp();
    for (mp = &sc->sc_m; (m = *mp) != NULL; mp = &m->m_next)
	if ((len -= M_DATASIZE(m)) <= 0) {
	    splx(s);
	    return (1);
	}

    for (;; mp = &m->m_next) {
	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == 0) {
	    m_freem(sc->sc_m);
	    sc->sc_m = NULL;
	    splx(s);
	    printf("ppp%d: can't allocate mbuf\n", sc->sc_if.if_unit);
	    return (0);
	}
	*mp = m;
	MCLGET(m, M_DONTWAIT);
	if ((len -= M_DATASIZE(m)) <= 0) {
	    splx(s);
	    return (1);
	}
    }
}

/*
 * Copy mbuf chain.  Would like to use m_copy(), but we need a real copy
 * of the data, not just copies of pointers to the data.
 */
static struct mbuf *