addrconf.c

linux 内核源代码

	struct in6_addr addr;
	struct inet6_dev    * idev;

	ASSERT_RTNL();

	if ((dev->type != ARPHRD_ETHER) &&
	    (dev->type != ARPHRD_FDDI) &&
	    (dev->type != ARPHRD_IEEE802_TR) &&
	    (dev->type != ARPHRD_ARCNET) &&
	    (dev->type != ARPHRD_INFINIBAND)) {
		/* Alas, we support only Ethernet autoconfiguration. */
		return;
	}

	idev = addrconf_add_dev(dev);
	if (idev == NULL)
		return;

	memset(&addr, 0, sizeof(struct in6_addr));
	addr.s6_addr32[0] = htonl(0xFE800000);

	if (ipv6_generate_eui64(addr.s6_addr + 8, dev) == 0)
		addrconf_add_linklocal(idev, &addr);
}

#if defined(CONFIG_IPV6_SIT) || defined(CONFIG_IPV6_SIT_MODULE)
static void addrconf_sit_config(struct net_device *dev)
{
	struct inet6_dev *idev;

	ASSERT_RTNL();

	/*
	 * Configure the tunnel with one of our IPv4
	 * addresses... we should configure all of
	 * our v4 addrs in the tunnel
	 */

	if ((idev = ipv6_find_idev(dev)) == NULL) {
		printk(KERN_DEBUG "init sit: add_dev failed\n");
		return;
	}

	sit_add_v4_addrs(idev);

	if (dev->flags&IFF_POINTOPOINT) {
		addrconf_add_mroute(dev);
		addrconf_add_lroute(dev);
	} else
		sit_route_add(dev);
}
#endif

static inline int
ipv6_inherit_linklocal(struct inet6_dev *idev, struct net_device *link_dev)
{
	struct in6_addr lladdr;

	if (!ipv6_get_lladdr(link_dev, &lladdr, IFA_F_TENTATIVE)) {
		addrconf_add_linklocal(idev, &lladdr);
		return 0;
	}
	return -1;
}

static void ip6_tnl_add_linklocal(struct inet6_dev *idev)
{
	struct net_device *link_dev;

	/* first try to inherit the link-local address from the link device */
	if (idev->dev->iflink &&
	    (link_dev = __dev_get_by_index(&init_net, idev->dev->iflink))) {
		if (!ipv6_inherit_linklocal(idev, link_dev))
			return;
	}
	/* then try to inherit it from any device */
	for_each_netdev(&init_net, link_dev) {
		if (!ipv6_inherit_linklocal(idev, link_dev))
			return;
	}
	printk(KERN_DEBUG "init ip6-ip6: add_linklocal failed\n");
}

/*
 * Autoconfigure tunnel with a link-local address so routing protocols,
 * DHCPv6, MLD etc. can be run over the virtual link
 */

static void addrconf_ip6_tnl_config(struct net_device *dev)
{
	struct inet6_dev *idev;

	ASSERT_RTNL();

	if ((idev = addrconf_add_dev(dev)) == NULL) {
		printk(KERN_DEBUG "init ip6-ip6: add_dev failed\n");
		return;
	}
	ip6_tnl_add_linklocal(idev);
}

static int addrconf_notify(struct notifier_block *this, unsigned long event,
			   void * data)
{
	struct net_device *dev = (struct net_device *) data;
	struct inet6_dev *idev = __in6_dev_get(dev);
	int run_pending = 0;
	int err;

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	switch(event) {
	case NETDEV_REGISTER:
		if (!idev && dev->mtu >= IPV6_MIN_MTU) {
			idev = ipv6_add_dev(dev);
			if (!idev)
				return notifier_from_errno(-ENOMEM);
		}
		break;
	case NETDEV_UP:
	case NETDEV_CHANGE:
		if (dev->flags & IFF_SLAVE)
			break;

		if (event == NETDEV_UP) {
			if (!addrconf_qdisc_ok(dev)) {
				/* device is not ready yet. */
				printk(KERN_INFO
					"ADDRCONF(NETDEV_UP): %s: "
					"link is not ready\n",
					dev->name);
				break;
			}

			if (!idev && dev->mtu >= IPV6_MIN_MTU)
				idev = ipv6_add_dev(dev);

			if (idev)
				idev->if_flags |= IF_READY;
		} else {
			if (!addrconf_qdisc_ok(dev)) {
				/* device is still not ready. */
				break;
			}

			if (idev) {
				if (idev->if_flags & IF_READY) {
					/* device is already configured. */
					break;
				}
				idev->if_flags |= IF_READY;
			}

			printk(KERN_INFO
					"ADDRCONF(NETDEV_CHANGE): %s: "
					"link becomes ready\n",
					dev->name);

			run_pending = 1;
		}

		switch(dev->type) {
#if defined(CONFIG_IPV6_SIT) || defined(CONFIG_IPV6_SIT_MODULE)
		case ARPHRD_SIT:
			addrconf_sit_config(dev);
			break;
#endif
		case ARPHRD_TUNNEL6:
			addrconf_ip6_tnl_config(dev);
			break;
		case ARPHRD_LOOPBACK:
			init_loopback(dev);
			break;

		default:
			addrconf_dev_config(dev);
			break;
		}
		if (idev) {
			if (run_pending)
				addrconf_dad_run(idev);

			/* If the MTU changed during the interface down, when the
			   interface up, the changed MTU must be reflected in the
			   idev as well as routers.
			 */
			if (idev->cnf.mtu6 != dev->mtu && dev->mtu >= IPV6_MIN_MTU) {
				rt6_mtu_change(dev, dev->mtu);
				idev->cnf.mtu6 = dev->mtu;
			}
			idev->tstamp = jiffies;
			inet6_ifinfo_notify(RTM_NEWLINK, idev);
			/* If the changed mtu during down is lower than IPV6_MIN_MTU
			   stop IPv6 on this interface.
			 */
			if (dev->mtu < IPV6_MIN_MTU)
				addrconf_ifdown(dev, event != NETDEV_DOWN);
		}
		break;

	case NETDEV_CHANGEMTU:
		if (idev && dev->mtu >= IPV6_MIN_MTU) {
			rt6_mtu_change(dev, dev->mtu);
			idev->cnf.mtu6 = dev->mtu;
			break;
		}

		if (!idev && dev->mtu >= IPV6_MIN_MTU) {
			idev = ipv6_add_dev(dev);
			if (idev)
				break;
		}

		/* MTU falled under IPV6_MIN_MTU. Stop IPv6 on this interface. */

	case NETDEV_DOWN:
	case NETDEV_UNREGISTER:
		/*
		 *	Remove all addresses from this interface.
		 */
		addrconf_ifdown(dev, event != NETDEV_DOWN);
		break;

	case NETDEV_CHANGENAME:
		if (idev) {
			snmp6_unregister_dev(idev);
#ifdef CONFIG_SYSCTL
			addrconf_sysctl_unregister(&idev->cnf);
			neigh_sysctl_unregister(idev->nd_parms);
			neigh_sysctl_register(dev, idev->nd_parms,
					      NET_IPV6, NET_IPV6_NEIGH, "ipv6",
					      &ndisc_ifinfo_sysctl_change,
					      NULL);
			addrconf_sysctl_register(idev, &idev->cnf);
#endif
			err = snmp6_register_dev(idev);
			if (err)
				return notifier_from_errno(err);
		}
		break;
	}

	return NOTIFY_OK;
}

/*
 *	addrconf module should be notified of a device going up
 */
static struct notifier_block ipv6_dev_notf = {
	.notifier_call = addrconf_notify,
	.priority = 0
};

static int addrconf_ifdown(struct net_device *dev, int how)
{
	struct inet6_dev *idev;
	struct inet6_ifaddr *ifa, **bifa;
	int i;

	ASSERT_RTNL();

	if (dev == init_net.loopback_dev && how == 1)
		how = 0;

	rt6_ifdown(dev);
	neigh_ifdown(&nd_tbl, dev);

	idev = __in6_dev_get(dev);
	if (idev == NULL)
		return -ENODEV;

	/* Step 1: remove reference to ipv6 device from parent device.
		   Do not dev_put!
	 */
	if (how == 1) {
		idev->dead = 1;

		/* protected by rtnl_lock */
		rcu_assign_pointer(dev->ip6_ptr, NULL);

		/* Step 1.5: remove snmp6 entry */
		snmp6_unregister_dev(idev);

	}

	/* Step 2: clear hash table */
	for (i=0; i<IN6_ADDR_HSIZE; i++) {
		bifa = &inet6_addr_lst[i];

		write_lock_bh(&addrconf_hash_lock);
		while ((ifa = *bifa) != NULL) {
			if (ifa->idev == idev) {
				*bifa = ifa->lst_next;
				ifa->lst_next = NULL;
				addrconf_del_timer(ifa);
				in6_ifa_put(ifa);
				continue;
			}
			bifa = &ifa->lst_next;
		}
		write_unlock_bh(&addrconf_hash_lock);
	}

	write_lock_bh(&idev->lock);

	/* Step 3: clear flags for stateless addrconf */
	if (how != 1)
		idev->if_flags &= ~(IF_RS_SENT|IF_RA_RCVD|IF_READY);

	/* Step 4: clear address list */
#ifdef CONFIG_IPV6_PRIVACY
	if (how == 1 && del_timer(&idev->regen_timer))
		in6_dev_put(idev);

	/* clear tempaddr list */
	while ((ifa = idev->tempaddr_list) != NULL) {
		idev->tempaddr_list = ifa->tmp_next;
		ifa->tmp_next = NULL;
		ifa->dead = 1;
		write_unlock_bh(&idev->lock);
		spin_lock_bh(&ifa->lock);

		if (ifa->ifpub) {
			in6_ifa_put(ifa->ifpub);
			ifa->ifpub = NULL;
		}
		spin_unlock_bh(&ifa->lock);
		in6_ifa_put(ifa);
		write_lock_bh(&idev->lock);
	}
#endif
	while ((ifa = idev->addr_list) != NULL) {
		idev->addr_list = ifa->if_next;
		ifa->if_next = NULL;
		ifa->dead = 1;
		addrconf_del_timer(ifa);
		write_unlock_bh(&idev->lock);

		__ipv6_ifa_notify(RTM_DELADDR, ifa);
		atomic_notifier_call_chain(&inet6addr_chain, NETDEV_DOWN, ifa);
		in6_ifa_put(ifa);

		write_lock_bh(&idev->lock);
	}
	write_unlock_bh(&idev->lock);

	/* Step 5: Discard multicast list */

	if (how == 1)
		ipv6_mc_destroy_dev(idev);
	else
		ipv6_mc_down(idev);

	idev->tstamp = jiffies;

	/* Shot the device (if unregistered) */

	if (how == 1) {
#ifdef CONFIG_SYSCTL
		addrconf_sysctl_unregister(&idev->cnf);
		neigh_sysctl_unregister(idev->nd_parms);
#endif
		neigh_parms_release(&nd_tbl, idev->nd_parms);
		neigh_ifdown(&nd_tbl, dev);
		in6_dev_put(idev);
	}
	return 0;
}

static void addrconf_rs_timer(unsigned long data)
{
	struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;

	if (ifp->idev->cnf.forwarding)
		goto out;

	if (ifp->idev->if_flags & IF_RA_RCVD) {
		/*
		 *	Announcement received after solicitation
		 *	was sent
		 */
		goto out;
	}

	spin_lock(&ifp->lock);
	if (ifp->probes++ < ifp->idev->cnf.rtr_solicits) {
		struct in6_addr all_routers;

		/* The wait after the last probe can be shorter */
		addrconf_mod_timer(ifp, AC_RS,
				   (ifp->probes == ifp->idev->cnf.rtr_solicits) ?
				   ifp->idev->cnf.rtr_solicit_delay :
				   ifp->idev->cnf.rtr_solicit_interval);
		spin_unlock(&ifp->lock);

		ipv6_addr_all_routers(&all_routers);

		ndisc_send_rs(ifp->idev->dev, &ifp->addr, &all_routers);
	} else {
		spin_unlock(&ifp->lock);
		/*
		 * Note: we do not support deprecated "all on-link"
		 * assumption any longer.
		 */
		printk(KERN_DEBUG "%s: no IPv6 routers present\n",
		       ifp->idev->dev->name);
	}

out:
	in6_ifa_put(ifp);
}

/*
 *	Duplicate Address Detection
 */
static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
{
	unsigned long rand_num;
	struct inet6_dev *idev = ifp->idev;

	if (ifp->flags & IFA_F_OPTIMISTIC)
		rand_num = 0;
	else
		rand_num = net_random() % (idev->cnf.rtr_solicit_delay ? : 1);

	ifp->probes = idev->cnf.dad_transmits;
	addrconf_mod_timer(ifp, AC_DAD, rand_num);
}

static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
{
	struct inet6_dev *idev = ifp->idev;
	struct net_device *dev = idev->dev;

	addrconf_join_solict(dev, &ifp->addr);

	net_srandom(ifp->addr.s6_addr32[3]);

	read_lock_bh(&idev->lock);
	if (ifp->dead)
		goto out;
	spin_lock_bh(&ifp->lock);

	if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
	    !(ifp->flags&IFA_F_TENTATIVE) ||
	    ifp->flags & IFA_F_NODAD) {
		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);
		spin_unlock_bh(&ifp->lock);
		read_unlock_bh(&idev->lock);

		addrconf_dad_completed(ifp);
		return;
	}

	if (!(idev->if_flags & IF_READY)) {
		spin_unlock_bh(&ifp->lock);
		read_unlock_bh(&idev->lock);
		/*
		 * If the defice is not ready:
		 * - keep it tentative if it is a permanent address.
		 * - otherwise, kill it.
		 */
		in6_ifa_hold(ifp);
		addrconf_dad_stop(ifp);
		return;
	}

	/*
	 * Optimistic nodes can start receiving
	 * Frames right away
	 */
	if(ifp->flags & IFA_F_OPTIMISTIC)
		ip6_ins_rt(ifp->rt);

	addrconf_dad_kick(ifp);
	spin_unlock_bh(&ifp->lock);
out:
	read_unlock_bh(&idev->lock);
}

static void addrconf_dad_timer(unsigned long data)
{
	struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;
	struct inet6_dev *idev = ifp->idev;
	struct in6_addr unspec;
	struct in6_addr mcaddr;

	read_lock_bh(&idev->lock);
	if (idev->dead) {
		read_unlock_bh(&idev->lock);
		goto out;
	}
	spin_lock_bh(&ifp->lock);
	if (ifp->probes == 0) {
		/*
		 * DAD was successful
		 */

		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);
		spin_unlock_bh(&ifp->lock);
		read_unlock_bh(&idev->lock);

		addrconf_dad_completed(ifp);

		goto out;
	}

	ifp->probes--;
	addrconf_mod_timer(ifp, AC_DAD, ifp->idev->nd_parms->retrans_time);
	spin_unlock_bh(&ifp->lock);
	read_unlock_bh(&idev->lock);

	/* send a neighbour solicitation for our addr */
	memset(&unspec, 0, sizeof(unspec));
	addrconf_addr_solict_mult(&ifp->addr, &mcaddr);
	ndisc_send_ns(ifp->idev->dev, NULL, &ifp->addr, &mcaddr, &unspec);
out:
	in6_ifa_put(ifp);
}

static void addrconf_dad_completed(struct inet6_ifaddr *ifp)
{
	struct net_device *	dev = ifp->idev->dev;

	/*
	 *	Configure the address for reception. Now it is valid.
	 */

	ipv6_ifa_notify(RTM_NEWADDR, ifp);

	/* If added prefix is link local and forwarding is off,
	   start sending router solicitations.
	 */

	if (ifp->idev->cnf.forwarding == 0 &&
	    ifp->idev->cnf.rtr_solicits > 0 &&
	    (dev->flags&IFF_LOOPBACK) == 0 &&
	    (