if_ether.c

vxworks下的实现网络TCPIP协议的原代码

 * desten is filled in.  If there is no entry in arptab,
 * set one up and broadcast a request for the IP address.
 * Hold onto this mbuf and resend it once the address
 * is finally resolved.  A return value of 1 indicates
 * that desten has been filled in and the packet should be sent
 * normally; a 0 return indicates that the packet has been
 * taken over here, either now or for later transmission.
 */
int
arpresolve(ac, rt, m, dst, desten)
	register struct arpcom *ac;
	register struct rtentry *rt;
	struct mbuf *m;
	register struct sockaddr *dst;
	register u_char *desten;
{
	register struct llinfo_arp *la;
	struct sockaddr_dl *sdl;
	int alen;                          /* Length of MAC address */
	u_long lna;                        /* Host portion if IP address */

	if (m != NULL)		/* check if mbuf is not null */
	    {
	    if (m->m_flags & M_BCAST)
		{	/* broadcast */
		bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,
		      sizeof(etherbroadcastaddr));
		return (1);
		}
	    if (m->m_flags & M_MCAST)
		{	/* multicast */
		ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
		return(1);
		}
	    }
	
	if (rt)
		la = (struct llinfo_arp *)rt->rt_llinfo;
	else {
		if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)))
			rt = la->la_rt;
	}
	if (la == 0 || rt == 0) {
		logMsg ("arpresolve: can't allocate llinfo",0,0,0,0,0,0);
		m_freem(m);
		return (0);
	}
	sdl = SDL(rt->rt_gateway);
	/*
	 * Check the address family and length is valid, the address
	 * is resolved; otherwise, try to resolve.
	 */
	if ((rt->rt_expire == 0 || rt->rt_expire > tickGet()) &&
	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
		bcopy(LLADDR(sdl), (char *)desten, sdl->sdl_alen);
		return 1;
	}

	/* If IFF_NOARP then make LL addr from IP host addr */
	 
	if (ac->ac_if.if_flags & IFF_NOARP) 
	    {

	    /* Set expiration of Route/ARP entry */

	    if (rt->rt_expire == 0)
		{
		rt->rt_expire = tickGet ();
		}

	    /* Set length of MAC address.  Default to Ethernet length. */

	    alen = (sdl->sdl_alen > 0 ? sdl->sdl_alen : 
		    sizeof (struct ether_addr));

	    if (alen < 3)
		{
		return (0);
		}

	    bcopy((caddr_t)ac->ac_enaddr, (char *)desten, alen - 3);

	    lna = in_lnaof(SIN(dst)->sin_addr);
	    desten[alen - 1]     = lna & 0xff;
	    desten[alen - 1 - 1] = (lna >> 8) & 0xff;
	    desten[alen - 1 - 2] = (lna >> 16) & 0x7f;
	    return (1);
	    }

	/*
	 * There is an arptab entry, but no ethernet address
	 * response yet.  Replace the held mbuf with this
	 * latest one.
	 */
	if (la->la_hold)
		m_freem(la->la_hold);
	la->la_hold = m;
	if (rt->rt_expire) {
		rt->rt_flags &= ~RTF_REJECT;
		if (arpRxmitTicks < 0)
		    arpRxmitTicks = ARP_RXMIT_TICKS_DFLT;
		if (la->la_asked == 0 || 
		    (tickGet () - rt->rt_expire >= arpRxmitTicks)) {
			rt->rt_expire = tickGet();
			if (la->la_asked++ < arp_maxtries)
				arpwhohas(ac, &(SIN(dst)->sin_addr));
			else {
				rt->rt_flags |= RTF_REJECT;
				rt->rt_expire += (sysClkRateGet() * arpt_down);
				la->la_asked = 0;
			}
		}
	}
	return (0);
}

/*
 * Common length and type checks are done here,
 * then the protocol-specific routine is called.
 */
void
arpintr()
{
	register struct mbuf *m;
	register struct arphdr *ar;
	int s;

	while (arpintrq.ifq_head) {
		s = splimp();
		IF_DEQUEUE(&arpintrq, m);
		splx(s);
		if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
        {
            if ( m == 0 )
                panic("arpintr: m is NULL\n");
            if ( (m->m_flags & M_PKTHDR) == 0 )
                panic("arpintr: M_PKTHDR is NOT set\n");

			panic("arpintr");
        }
		if (m->m_len >= sizeof(struct arphdr) &&
		    (ar = mtod(m, struct arphdr *)) &&
		    ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
		    m->m_len >=
		      sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
			switch (ntohs(ar->ar_pro)) {

			case ETHERTYPE_IP:
			case ETHERTYPE_IPTRAILERS:
#ifdef PROXY_HOOK
			        if (proxyArpHook != NULL)
				    (* proxyArpHook)
					((struct arpcom *)m->m_pkthdr.rcvif,m);
#endif
				in_arpinput(m);
				continue;
			}
		m_freem(m);
	}
}

/*
 * ARP for Internet protocols on 10 Mb/s Ethernet.
 * Algorithm is that given in RFC 826.
 * In addition, a sanity check is performed on the sender
 * protocol address, to catch impersonators.
 * We no longer handle negotiations for use of trailer protocol:
 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
 * along with IP replies if we wanted trailers sent to us,
 * and also sent them in response to IP replies.
 * This allowed either end to announce the desire to receive
 * trailer packets.
 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
 * but formerly didn't normally send requests.
 */
static void
in_arpinput(m)
	struct mbuf *m;
{
	register struct ether_arp *ea;
	register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
	struct ether_header *eh;
	register struct llinfo_arp *la = 0;
	register struct rtentry *rt;
	struct in_ifaddr *ia, *maybe_ia = 0;
	struct sockaddr_dl *sdl;
	struct sockaddr sa;
	struct in_addr isaddr, itaddr, myaddr;
	int op;

	ea = mtod(m, struct ether_arp *);
	op = ntohs(ea->arp_op);
	bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr));
	bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr));
	for (ia = in_ifaddr; ia; ia = ia->ia_next)
		if (ia->ia_ifp == &ac->ac_if) {
			maybe_ia = ia;
			if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) ||
			     (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr))
				break;
		}
	if (maybe_ia == 0)
		goto out;
	myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
	    sizeof (ea->arp_sha)))
		goto out;	/* it's from me, ignore it. */
	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
	    sizeof (ea->arp_sha))) {
		logMsg (
		    "arp: ether address is broadcast for IP address %x!\n",
		    (int)ntohl(isaddr.s_addr), 0,0,0,0,0);
		goto out;
	}
	if (isaddr.s_addr == myaddr.s_addr) {
		logMsg(
		   "duplicate IP address %08x sent from ethernet address %s\n",
		   (int)ntohl(isaddr.s_addr), (int)ether_sprintf(ea->arp_sha),
		   0,0,0,0);
		itaddr = myaddr;
		goto reply;
	}
	la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
	if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
		if (sdl->sdl_alen &&
		    bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
			logMsg("arp info overwritten for %08x by %s\n",
			    (int) ntohl(isaddr.s_addr), 
			    (int) ether_sprintf(ea->arp_sha),0,0,0,0);
		bcopy((caddr_t)ea->arp_sha, LLADDR(sdl),
		    sdl->sdl_alen = sizeof(ea->arp_sha));
		if (rt->rt_expire)
			rt->rt_expire = tickGet() + (sysClkRateGet() * 
						     arpt_keep);
		rt->rt_flags &= ~RTF_REJECT;
		la->la_asked = 0;
		if (la->la_hold) {
			(*ac->ac_if.if_output)(&ac->ac_if, la->la_hold,
				rt_key(rt), rt);
			la->la_hold = 0;
		}
	}
reply:
	if (op != ARPOP_REQUEST) {
	out:
		m_freem(m);
		return;
	}
	if (itaddr.s_addr == myaddr.s_addr) {
		/* I am the target */
		bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
		    sizeof(ea->arp_sha));
		bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,
		    sizeof(ea->arp_sha));
	} else {
		la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
		if (la == 0)
			goto out;
		rt = la->la_rt;
		bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
		    sizeof(ea->arp_sha));
		sdl = SDL(rt->rt_gateway);
		bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
	}

	bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa));
	bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
	ea->arp_op = htons(ARPOP_REPLY);
	ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */
	eh = (struct ether_header *)sa.sa_data;
	bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost,
	    sizeof(eh->ether_dhost));
	eh->ether_type = ETHERTYPE_ARP;
	sa.sa_family = AF_UNSPEC;
	sa.sa_len = sizeof(sa);
	(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
	return;
}

/*
 * Free an arp entry.
 */
void
arptfree(la)
	register struct llinfo_arp *la;
{
	register struct rtentry *rt = la->la_rt;
	register struct sockaddr_dl *sdl;

	if (rt == 0)
		panic("arptfree");
	if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
	    sdl->sdl_family == AF_LINK) {
		sdl->sdl_alen = 0;
		la->la_asked = 0;
		rt->rt_flags &= ~RTF_REJECT;
		return;
	}

	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
	    0, (struct rtentry **)0);
}

/*
 * Lookup or enter a new address in arptab.
 */
static struct llinfo_arp *
arplookup(addr, create, proxy)
	u_long addr;
	int create, proxy;
{
	register struct rtentry *rt;
	static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };

	sin.sin_addr.s_addr = addr;
	sin.sin_other = proxy ? SIN_PROXY : 0;
	rt = rtalloc1((struct sockaddr *)&sin, create);
	if (rt == 0)
		return (0);
	rt->rt_refcnt--;
	if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 ||
	    rt->rt_gateway->sa_family != AF_LINK) {
		if (create)
			logMsg("arptnew failed on %x\n", (int)ntohl(addr),
			0,0,0,0,0);
		return (0);
	}
	return ((struct llinfo_arp *)rt->rt_llinfo);
}

int arpioctl
    (
    int 	cmd,
    caddr_t	data
    )
    {
    register struct arpreq *		ar = (struct arpreq *)data;
    register struct sockaddr_in *	soInAddr;

    register struct llinfo_arp *	la = NULL;
    register struct rtentry *		rt = NULL;
    struct rtentry * 			pNewRt;
    struct sockaddr_dl * 		sdl;
    struct sockaddr_in 			rtmask;
    struct sockaddr_in * 		pMask;

    struct sockaddr_inarp 		ipaddr;
    struct sockaddr_dl 			arpaddr;
    int error = OK;
    int flags = 0;

    BOOL proxy = FALSE;
    BOOL export = FALSE;

    if (ar->arp_pa.sa_family != AF_INET ||
	ar->arp_ha.sa_family != AF_UNSPEC)
	return (EAFNOSUPPORT);

    soInAddr = (struct sockaddr_in *)&ar->arp_pa;

    switch (cmd) 
	{
	case SIOCSARP:
            if (ar->arp_flags & ATF_PUBL)
                {
                flags |= RTF_ANNOUNCE;
                proxy = TRUE;
                }

            /* Search for existing entry with same address. */
   
            bzero ( (char *)&ipaddr, sizeof (ipaddr));
            ipaddr.sin_len = sizeof (ipaddr);
            ipaddr.sin_family = AF_INET;
            ipaddr.sin_addr.s_addr = soInAddr->sin_addr.s_addr;

            rt = rtalloc1 ((struct sockaddr *)&ipaddr, 0);
            if (rt)
                {
                rt->rt_refcnt--;
                if (soInAddr->sin_addr.s_addr ==
                        ((struct sockaddr_in *)rt_key (rt))->sin_addr.s_addr)
                    {
                    /* Matching entry found. Check address type. */

                    if ( (rt->rt_flags & RTF_GATEWAY) || 
                              (rt->rt_flags & RTF_LLINFO) == 0 || 
                                     rt->rt_gateway->sa_family != AF_LINK)
                        {
                        /* Host entry found: must create proxy entry. */

                        if ( !(ar->arp_flags & ATF_PUBL))
                            return (EINVAL);

                        /* 
                         * Set flag to prevent replacement of current entry 
                         * by creating entry which includes SIN_PROXY flag.
                         */

                        export = TRUE;
                        }
                    }
                }

            /*
             * Search completed. Get the interface type and index value
             * from the parent route.
             */

            if (rt)
                {
                /*
                 * For remote hosts or networks, the gateway's associated
                 * route entry contains the interface values.
                 */

                if (rt->rt_flags & RTF_GATEWAY)
                    {
                    if (rt->rt_gwroute == 0)
                        return (EHOSTUNREACH);
                    else