if_ppp.c

经典的ppp程序

	    snit_intr(ifp, mb, &nif);
	}
#endif

/*
 * For Digital UNIX, there's space set aside in the header mbuf
 * for the interface info.
 *
 * For Sun it's smuggled around via a pointer at the front of the mbuf.
 */
#ifdef __osf__
        mb->m_pkthdr.rcvif = ifp;
        mb->m_pkthdr.len = len;
#else
	mb->m_off -= sizeof(struct ifnet *);
	mb->m_len += sizeof(struct ifnet *);
	*mtod(mb, struct ifnet **) = ifp;
#endif

	inq = 0;
	switch (proto) {
	case PPP_IP:
	    inq = &ipintrq;
	    schednetisr(NETISR_IP);
	}

	if (inq != 0) {
	    s = splhigh();
	    if (IF_QFULL(inq)) {
		IF_DROP(inq);
		++ifp->if_ierrors;
		if (sp->flags & DBGLOG)
		    printf("if_ppp: inq full, proto=%x\n", proto);
		m_freem(mb);
	    } else {
		IF_ENQUEUE(inq, mb);
	    }
	    splx(s);
	} else {
	    if (sp->flags & DBGLOG)
		printf("if_ppp%d: proto=%x?\n", ifp->if_unit, proto);
	    ++ifp->if_ierrors;
	    m_freem(mb);
	}
	break;

    default:
	putnext(q, mp);
    }
    return 0;
}

/*
 * Network code wants to output a packet.
 * Turn it into a STREAMS message and send it down.
 */
static int
if_ppp_output(ifp, m0, dst)
    struct ifnet *ifp;
    struct mbuf *m0;
    struct sockaddr *dst;
{
    mblk_t *mp;
    int proto, s;
    if_ppp_t *sp;
    u_char *p;

    if ((ifp->if_flags & IFF_UP) == 0) {
	m_freem(m0);
	return ENETDOWN;
    }

    if ((unsigned)ifp->if_unit >= ppp_nalloc) {
#ifdef DEBUG
	printf("if_ppp_output: unit %d?\n", ifp->if_unit);
#endif
	m_freem(m0);
	return EINVAL;
    }
    sp = states[ifp->if_unit];
    if (sp == 0) {
#ifdef DEBUG
	printf("if_ppp_output: no queue?\n");
#endif
	m_freem(m0);
	return ENETDOWN;
    }

    if (sp->flags & DBGLOG) {
	p = mtod(m0, u_char *);
	printf("if_ppp_output%d: af=%d data=%x %x %x %x %x %x %x %x q=%x\n",
	       ifp->if_unit, dst->sa_family, p[0], p[1], p[2], p[3], p[4],
	       p[5], p[6], p[7], sp->q);
    }

    switch (dst->sa_family) {
    case AF_INET:
	proto = PPP_IP;
#ifdef SNIT_SUPPORT
	if (ifp->if_flags & IFF_PROMISC) {
	    struct nit_if nif;
	    struct mbuf *m;
	    int len;

	    for (len = 0, m = m0; m != NULL; m = m->m_next)
		len += m->m_len;
	    nif.nif_header = (caddr_t) &snit_ehdr;
	    nif.nif_hdrlen = sizeof(snit_ehdr);
	    nif.nif_bodylen = len;
	    nif.nif_promisc = 0;
	    snit_intr(ifp, m0, &nif);
	}
#endif
	break;

    default:
	m_freem(m0);
	return EAFNOSUPPORT;
    }

    ++ifp->if_opackets;
    mp = make_message(m0, PPP_HDRLEN);
    m_freem(m0);
    if (mp == 0) {
	++ifp->if_oerrors;
	return ENOBUFS;
    }
    mp->b_rptr -= PPP_HDRLEN;
    mp->b_rptr[0] = PPP_ALLSTATIONS;
    mp->b_rptr[1] = PPP_UI;
    mp->b_rptr[2] = proto >> 8;
    mp->b_rptr[3] = proto;

    s = splstr();
    if (sp->flags & DBGLOG)
	printf("if_ppp: putnext(%x, %x), r=%x w=%x p=%x\n",
	       sp->q, mp, mp->b_rptr, mp->b_wptr, proto);
    putnext(sp->q, mp);
    splx(s);

    return 0;
}

/*
 * Socket ioctl routine for ppp interfaces.
 */
static int
if_ppp_ioctl(ifp, cmd, data)
    struct ifnet *ifp;
    u_int cmd;
    caddr_t data;
{
    int s, error;
    struct ifreq *ifr = (struct ifreq *) data;
    struct ifaddr *ifa = (struct ifaddr *) data;
    u_short mtu;

    error = 0;
    s = splimp();
    switch (cmd) {
    case SIOCSIFFLAGS:
	if ((ifp->if_flags & IFF_RUNNING) == 0)
	    ifp->if_flags &= ~IFF_UP;
	break;

    case SIOCSIFADDR:
	if (IFA_ADDR(ifa).sa_family != AF_INET)
	    error = EAFNOSUPPORT;
	break;

    case SIOCSIFDSTADDR:
	if (IFA_ADDR(ifa).sa_family != AF_INET)
	    error = EAFNOSUPPORT;
	break;

    case SIOCSIFMTU:
	if ((error = NOTSUSER()) != 0)
	    break;
#ifdef __osf__
	/* this hack is necessary because ifioctl checks ifr_data
	 * in 4.0 and 5.0, but ifr_data and ifr_metric overlay each 
	 * other in the definition of struct ifreq so pppd can't set both.
	 */
        bcopy(ifr->ifr_data, &mtu, sizeof (u_short));
        ifr->ifr_mtu = mtu;
#endif

	if (ifr->ifr_mtu < PPP_MINMTU || ifr->ifr_mtu > PPP_MAXMTU) {
	    error = EINVAL;
	    break;
	}
	ifp->if_mtu = ifr->ifr_mtu;
	break;

    case SIOCGIFMTU:
	ifr->ifr_mtu = ifp->if_mtu;
	break;

    case SIOCADDMULTI:
    case SIOCDELMULTI:
	switch(ifr->ifr_addr.sa_family) {
	case AF_INET:
	    break;
	default:
	    error = EAFNOSUPPORT;
	    break;
	}
	break;

    default:
	error = EINVAL;
    }
    splx(s);
    return (error);
}

/*
 * Turn a STREAMS message into an mbuf chain.
 */
static struct mbuf *
make_mbufs(mp, off)
    mblk_t *mp;
    int off;
{
    struct mbuf *head, **prevp, *m;
    int len, space, n;
    unsigned char *cp, *dp;

    len = msgdsize(mp);
    if (len == 0)
	return 0;
    prevp = &head;
    space = 0;
    cp = mp->b_rptr;
#ifdef __osf__
    MGETHDR(m, M_DONTWAIT, MT_DATA);
    m->m_len = 0;
    space = MHLEN;
    *prevp = m;
    prevp = &m->m_next;
    dp = mtod(m, unsigned char *);
    len -= space;
    off = 0;
#endif
    for (;;) {
	while (cp >= mp->b_wptr) {
	    mp = mp->b_cont;
	    if (mp == 0) {
		*prevp = 0;
		return head;
	    }
	    cp = mp->b_rptr;
	}
	n = mp->b_wptr - cp;
	if (space == 0) {
	    MGET(m, M_DONTWAIT, MT_DATA);
	    *prevp = m;
	    if (m == 0) {
		if (head != 0)
		    m_freem(head);
		return 0;
	    }
	    if (len + off > 2 * MLEN) {
#ifdef __osf__
		MCLGET(m, M_DONTWAIT);
#else
		MCLGET(m);
#endif
	    }
#ifdef __osf__
	    space = ((m->m_flags & M_EXT) ? MCLBYTES : MLEN);
#else
	    space = (m->m_off > MMAXOFF? MCLBYTES: MLEN) - off;
	    m->m_off += off;
#endif
	    m->m_len = 0;
	    len -= space;
	    dp = mtod(m, unsigned char *);
	    off = 0;
	    prevp = &m->m_next;
	}
	if (n > space)
	    n = space;
	bcopy(cp, dp, n);
	cp += n;
	dp += n;
	space -= n;
	m->m_len += n;
    }
}

/*
 * Turn an mbuf chain into a STREAMS message.
 */
#define ALLOCB_MAX	4096

static mblk_t *
make_message(m, off)
    struct mbuf *m;
    int off;
{
    mblk_t *head, **prevp, *mp;
    int len, space, n, nb;
    unsigned char *cp, *dp;
    struct mbuf *nm;

    len = 0;
    for (nm = m; nm != 0; nm = nm->m_next)
	len += nm->m_len;
    prevp = &head;
    space = 0;
    cp = mtod(m, unsigned char *);
    nb = m->m_len;
    for (;;) {
	while (nb <= 0) {
	    m = m->m_next;
	    if (m == 0) {
		*prevp = 0;
		return head;
	    }
	    cp = mtod(m, unsigned char *);
	    nb = m->m_len;
	}
	if (space == 0) {
	    space = len + off;
	    if (space > ALLOCB_MAX)
		space = ALLOCB_MAX;
	    mp = allocb(space, BPRI_LO);
	    *prevp = mp;
	    if (mp == 0) {
		if (head != 0)
		    freemsg(head);
		return 0;
	    }
	    dp = mp->b_rptr += off;
	    space -= off;
	    len -= space;
	    off = 0;
	    prevp = &mp->b_cont;
	}
	n = nb < space? nb: space;
	bcopy(cp, dp, n);
	cp += n;
	dp += n;
	nb -= n;
	space -= n;
	mp->b_wptr = dp;
    }
}

/*
 * Digital UNIX doesn't allow for removing ifnet structures
 * from the list.  But then we're not using this as a loadable
 * module anyway, so that's OK.
 *
 * Under SunOS, this should allow the module to be unloaded.
 * Unfortunately, it doesn't seem to detach all the references,
 * so your system may well crash after you unload this module :-(
 */
#ifndef __osf__

/*
 * Remove an interface from the system.
 * This routine contains magic.
 */
#include <net/route.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>

static void
ppp_if_detach(ifp)
    struct ifnet *ifp;
{
    int s;
    struct inpcb *pcb;
    struct ifaddr *ifa;
    struct in_ifaddr **inap;
    struct ifnet **ifpp;

    s = splhigh();

    /*
     * Clear the interface from any routes currently cached in
     * TCP or UDP protocol control blocks.
     */
    for (pcb = tcb.inp_next; pcb != &tcb; pcb = pcb->inp_next)
	if (pcb->inp_route.ro_rt && pcb->inp_route.ro_rt->rt_ifp == ifp)
	    in_losing(pcb);
    for (pcb = udb.inp_next; pcb != &udb; pcb = pcb->inp_next)
	if (pcb->inp_route.ro_rt && pcb->inp_route.ro_rt->rt_ifp == ifp)
	    in_losing(pcb);

    /*
     * Delete routes through all addresses of the interface.
     */
    for (ifa = ifp->if_addrlist; ifa != 0; ifa = ifa->ifa_next) {
	rtinit(ifa, ifa, SIOCDELRT, RTF_HOST);
	rtinit(ifa, ifa, SIOCDELRT, 0);
    }

    /*
     * Unlink the interface's address(es) from the in_ifaddr list.
     */
    for (inap = &in_ifaddr; *inap != 0; ) {
	if ((*inap)->ia_ifa.ifa_ifp == ifp)
	    *inap = (*inap)->ia_next;
	else
	    inap = &(*inap)->ia_next;
    }

    /*
     * Delete the interface from the ifnet list.
     */
    for (ifpp = &ifnet; (*ifpp) != 0; ) {
	if (*ifpp == ifp)
	    break;
	ifpp = &(*ifpp)->if_next;
    }
    if (*ifpp == 0)
	printf("couldn't find interface ppp%d in ifnet list\n", ifp->if_unit);
    else
	*ifpp = ifp->if_next;

    splx(s);
}

#endif /* __osf__ */