1 files changed, 91 insertions, 15 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e035896..38274c2 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -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;
 
-	rand_num = net_random() % (idev->cnf.rtr_solicit_delay ? : 1);
+	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)
@@ -3578,7 +3636,14 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 
 	switch (event) {
 	case RTM_NEWADDR:
-		ip6_ins_rt(ifp->rt);
+		/*
+		 * 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);
 		break;
@@ -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 */
 		}