Commit 95c385b4 authored by Neil Horman's avatar Neil Horman Committed by David S. Miller
Browse files

[IPV6] ADDRCONF: Optimistic Duplicate Address Detection (RFC 4429) Support. 



Nominally an autoconfigured IPv6 address is added to an interface in the
Tentative state (as per RFC 2462).  Addresses in this state remain in this
state while the Duplicate Address Detection process operates on them to
determine their uniqueness on the network.  During this period, these
tentative addresses may not be used for communication, increasing the time
before a node may be able to communicate on a network.  Using Optimistic
Duplicate Address Detection, autoconfigured addresses may be used
immediately for communication on the network, as long as certain rules are
followed to avoid conflicts with other nodes during the Duplicate Address
Detection process.

Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 502b0935

include/linux/if_addr.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ enum 
#define IFA_F_TEMPORARY		IFA_F_SECONDARY



#define	IFA_F_NODAD		0x02

#define IFA_F_OPTIMISTIC	0x04

#define	IFA_F_HOMEADDRESS	0x10

#define IFA_F_DEPRECATED	0x20

#define IFA_F_TENTATIVE		0x40

include/linux/ipv6.h

+4 −0
Original line number Diff line number Diff line
@@ -178,6 +178,9 @@ struct ipv6_devconf { 
#endif

	__s32		proxy_ndp;

	__s32		accept_source_route;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD

	__s32		optimistic_dad;

#endif

	void		*sysctl;

};
@@ -208,6 +211,7 @@ enum { 
	DEVCONF_PROXY_NDP,

	__DEVCONF_OPTIMISTIC_DAD,

	DEVCONF_ACCEPT_SOURCE_ROUTE,

	DEVCONF_OPTIMISTIC_DAD,

	DEVCONF_MAX

};

include/net/addrconf.h

+3 −1
Original line number Diff line number Diff line
@@ -73,7 +73,9 @@ extern int ipv6_get_saddr(struct dst_entry *dst, 
extern int			ipv6_dev_get_saddr(struct net_device *dev, 

					       struct in6_addr *daddr,

					       struct in6_addr *saddr);

extern int			ipv6_get_lladdr(struct net_device *dev, struct in6_addr *);

extern int			ipv6_get_lladdr(struct net_device *dev,

						struct in6_addr *addr,

						unsigned char banned_flags);

extern int			ipv6_rcv_saddr_equal(const struct sock *sk, 

						      const struct sock *sk2);

extern void			addrconf_join_solict(struct net_device *dev,

net/ipv6/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -57,6 +57,16 @@ config IPV6_ROUTE_INFO 


	  If unsure, say N.



config IPV6_OPTIMISTIC_DAD

	bool "IPv6: Enable RFC 4429 Optimistic DAD (EXPERIMENTAL)"

	depends on IPV6 && EXPERIMENTAL

	---help---

	  This is experimental support for optimistic Duplicate

	  Address Detection.  It allows for autoconfigured addresses

	  to be used more quickly.



	  If unsure, say N.



config INET6_AH

	tristate "IPv6: AH transformation"

	depends on IPV6

net/ipv6/addrconf.c

+91 −15
Original line number Diff line number Diff line
@@ -530,6 +530,16 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen, 


	ifa->rt = rt;



	/*

	 * part one of RFC 4429, section 3.3

	 * We should not configure an address as

	 * optimistic if we do not yet know the link

	 * layer address of our nexhop router

	 */



	if (rt->rt6i_nexthop == NULL)

		ifa->flags &= ~IFA_F_OPTIMISTIC;



	ifa->idev = idev;

	in6_dev_hold(idev);

	/* For caller */
@@ -706,6 +716,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *i 
	int tmp_plen;

	int ret = 0;

	int max_addresses;

	u32 addr_flags;



	write_lock(&idev->lock);

	if (ift) {
@@ -763,10 +774,17 @@ retry: 
	spin_unlock_bh(&ifp->lock);



	write_unlock(&idev->lock);



	addr_flags = IFA_F_TEMPORARY;

	/* set in addrconf_prefix_rcv() */

	if (ifp->flags & IFA_F_OPTIMISTIC)

		addr_flags |= IFA_F_OPTIMISTIC;



	ift = !max_addresses ||

	      ipv6_count_addresses(idev) < max_addresses ?

		ipv6_add_addr(idev, &addr, tmp_plen,

			      ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK, IFA_F_TEMPORARY) : NULL;

			      ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK,

			      addr_flags) : NULL;

	if (!ift || IS_ERR(ift)) {

		in6_ifa_put(ifp);

		in6_dev_put(idev);
@@ -898,13 +916,14 @@ int ipv6_dev_get_saddr(struct net_device *daddr_dev, 
			 * - Tentative Address (RFC2462 section 5.4)

			 *  - A tentative address is not considered

			 *    "assigned to an interface" in the traditional

			 *    sense.

			 *    sense, unless it is also flagged as optimistic.

			 * - Candidate Source Address (section 4)

			 *  - In any case, anycast addresses, multicast

			 *    addresses, and the unspecified address MUST

			 *    NOT be included in a candidate set.

			 */

			if (ifa->flags & IFA_F_TENTATIVE)

			if ((ifa->flags & IFA_F_TENTATIVE) &&

			    (!(ifa->flags & IFA_F_OPTIMISTIC)))

				continue;

			if (unlikely(score.addr_type == IPV6_ADDR_ANY ||

				     score.addr_type & IPV6_ADDR_MULTICAST)) {
@@ -963,15 +982,17 @@ int ipv6_dev_get_saddr(struct net_device *daddr_dev, 
				}

			}



			/* Rule 3: Avoid deprecated address */

			/* Rule 3: Avoid deprecated and optimistic addresses */

			if (hiscore.rule < 3) {

				if (ipv6_saddr_preferred(hiscore.addr_type) ||

				    !(ifa_result->flags & IFA_F_DEPRECATED))

				   (((ifa_result->flags &

				    (IFA_F_DEPRECATED|IFA_F_OPTIMISTIC)) == 0)))

					hiscore.attrs |= IPV6_SADDR_SCORE_PREFERRED;

				hiscore.rule++;

			}

			if (ipv6_saddr_preferred(score.addr_type) ||

			    !(ifa->flags & IFA_F_DEPRECATED)) {

			   (((ifa_result->flags &

			    (IFA_F_DEPRECATED|IFA_F_OPTIMISTIC)) == 0))) {

				score.attrs |= IPV6_SADDR_SCORE_PREFERRED;

				if (!(hiscore.attrs & IPV6_SADDR_SCORE_PREFERRED)) {

					score.rule = 3;
@@ -1111,7 +1132,8 @@ int ipv6_get_saddr(struct dst_entry *dst, 


EXPORT_SYMBOL(ipv6_get_saddr);



int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)

int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,

		    unsigned char banned_flags)

{

	struct inet6_dev *idev;

	int err = -EADDRNOTAVAIL;
@@ -1122,7 +1144,7 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr) 


		read_lock_bh(&idev->lock);

		for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {

			if (ifp->scope == IFA_LINK && !(ifp->flags&IFA_F_TENTATIVE)) {

			if (ifp->scope == IFA_LINK && !(ifp->flags & banned_flags)) {

				ipv6_addr_copy(addr, &ifp->addr);

				err = 0;

				break;
@@ -1674,6 +1696,13 @@ ok: 


		if (ifp == NULL && valid_lft) {

			int max_addresses = in6_dev->cnf.max_addresses;

			u32 addr_flags = 0;



#ifdef CONFIG_IPV6_OPTIMISTIC_DAD

			if (in6_dev->cnf.optimistic_dad &&

			    !ipv6_devconf.forwarding)

				addr_flags = IFA_F_OPTIMISTIC;

#endif



			/* Do not allow to create too much of autoconfigured

			 * addresses; this would be too easy way to crash kernel.
@@ -1681,7 +1710,8 @@ ok: 
			if (!max_addresses ||

			    ipv6_count_addresses(in6_dev) < max_addresses)

				ifp = ipv6_add_addr(in6_dev, &addr, pinfo->prefix_len,

						    addr_type&IPV6_ADDR_SCOPE_MASK, 0);

						    addr_type&IPV6_ADDR_SCOPE_MASK,

						    addr_flags);



			if (!ifp || IS_ERR(ifp)) {

				in6_dev_put(in6_dev);
@@ -1889,6 +1919,11 @@ static int inet6_addr_add(int ifindex, struct in6_addr *pfx, int plen, 


		addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,

				      jiffies_to_clock_t(valid_lft * HZ), flags);

		/*

		 * Note that section 3.1 of RFC 4429 indicates

		 * that the Optimistic flag should not be set for

		 * manually configured addresses

		 */

		addrconf_dad_start(ifp, 0);

		in6_ifa_put(ifp);

		addrconf_verify(0);
@@ -2065,8 +2100,16 @@ static void init_loopback(struct net_device *dev) 
static void addrconf_add_linklocal(struct inet6_dev *idev, struct in6_addr *addr)

{

	struct inet6_ifaddr * ifp;

	u32 addr_flags = IFA_F_PERMANENT;



#ifdef CONFIG_IPV6_OPTIMISTIC_DAD

	if (idev->cnf.optimistic_dad &&

	    !ipv6_devconf.forwarding)

		addr_flags |= IFA_F_OPTIMISTIC;

#endif





	ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK, IFA_F_PERMANENT);

	ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK, addr_flags);

	if (!IS_ERR(ifp)) {

		addrconf_prefix_route(&ifp->addr, ifp->prefix_len, idev->dev, 0, 0);

		addrconf_dad_start(ifp, 0);
@@ -2134,7 +2177,7 @@ ipv6_inherit_linklocal(struct inet6_dev *idev, struct net_device *link_dev) 
{

	struct in6_addr lladdr;



	if (!ipv6_get_lladdr(link_dev, &lladdr)) {

	if (!ipv6_get_lladdr(link_dev, &lladdr, IFA_F_TENTATIVE)) {

		addrconf_add_linklocal(idev, &lladdr);

		return 0;

	}
@@ -2479,7 +2522,11 @@ 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);

}
@@ -2501,7 +2548,7 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags) 
	if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||

	    !(ifp->flags&IFA_F_TENTATIVE) ||

	    ifp->flags & IFA_F_NODAD) {

		ifp->flags &= ~IFA_F_TENTATIVE;

		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);

		spin_unlock_bh(&ifp->lock);

		read_unlock_bh(&idev->lock);
@@ -2521,6 +2568,14 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags) 
		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:
@@ -2545,7 +2600,7 @@ static void addrconf_dad_timer(unsigned long data) 
		 * DAD was successful

		 */



		ifp->flags &= ~IFA_F_TENTATIVE;

		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC);

		spin_unlock_bh(&ifp->lock);

		read_unlock_bh(&idev->lock);
@@ -3364,6 +3419,9 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, 
#endif

	array[DEVCONF_PROXY_NDP] = cnf->proxy_ndp;

	array[DEVCONF_ACCEPT_SOURCE_ROUTE] = cnf->accept_source_route;

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD

	array[DEVCONF_OPTIMISTIC_DAD] = cnf->optimistic_dad;

#endif

}



static inline size_t inet6_if_nlmsg_size(void)
@@ -3578,6 +3636,13 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp) 


	switch (event) {

	case RTM_NEWADDR:

		/*

		 * If the address was optimistic

		 * we inserted the route at the start of

		 * our DAD process, so we don't need

		 * to do it again

		 */

		if (!(ifp->rt->rt6i_node))

			ip6_ins_rt(ifp->rt);

		if (ifp->idev->cnf.forwarding)

			addrconf_join_anycast(ifp);
@@ -3899,6 +3964,17 @@ static struct addrconf_sysctl_table 
			.mode		=	0644,

			.proc_handler	=	&proc_dointvec,

		},

#ifdef CONFIG_IPV6_OPTIMISTIC_DAD

		{

			.ctl_name	=	CTL_UNNUMBERED,

			.procname       =       "optimistic_dad",

			.data           =       &ipv6_devconf.optimistic_dad,

			.maxlen         =       sizeof(int),

			.mode           =       0644,

			.proc_handler   =       &proc_dointvec,



		},

#endif

		{

			.ctl_name	=	0,	/* sentinel */

		}

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