addrconf: put prefix address add in an own function

This patch moves the functionality to add a RA PIO prefix generated
address in an own function. This move prepares to add a hook for
adding a second address for a second link-layer address. E.g. short
address for 802.15.4 6LoWPAN.

Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Alexander Aring <aar@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -2333,12 +2333,110 @@ static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
 	       idev->addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
 }
 
+static int addrconf_prefix_rcv_add_addr(struct net *net,
+					struct net_device *dev,
+					const struct prefix_info *pinfo,
+					struct inet6_dev *in6_dev,
+					const struct in6_addr *addr,
+					int addr_type, u32 addr_flags,
+					bool sllao, bool tokenized,
+					__u32 valid_lft, u32 prefered_lft)
+{
+	struct inet6_ifaddr *ifp = ipv6_get_ifaddr(net, addr, dev, 1);
+	int create = 0, update_lft = 0;
+
+	if (!ifp && valid_lft) {
+		int max_addresses = in6_dev->cnf.max_addresses;
+
+#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
+		if (in6_dev->cnf.optimistic_dad &&
+		    !net->ipv6.devconf_all->forwarding && sllao)
+			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.
+		 */
+		if (!max_addresses ||
+		    ipv6_count_addresses(in6_dev) < max_addresses)
+			ifp = ipv6_add_addr(in6_dev, addr, NULL,
+					    pinfo->prefix_len,
+					    addr_type&IPV6_ADDR_SCOPE_MASK,
+					    addr_flags, valid_lft,
+					    prefered_lft);
+
+		if (IS_ERR_OR_NULL(ifp))
+			return -1;
+
+		update_lft = 0;
+		create = 1;
+		spin_lock_bh(&ifp->lock);
+		ifp->flags |= IFA_F_MANAGETEMPADDR;
+		ifp->cstamp = jiffies;
+		ifp->tokenized = tokenized;
+		spin_unlock_bh(&ifp->lock);
+		addrconf_dad_start(ifp);
+	}
+
+	if (ifp) {
+		u32 flags;
+		unsigned long now;
+		u32 stored_lft;
+
+		/* update lifetime (RFC2462 5.5.3 e) */
+		spin_lock_bh(&ifp->lock);
+		now = jiffies;
+		if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
+			stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
+		else
+			stored_lft = 0;
+		if (!update_lft && !create && stored_lft) {
+			const u32 minimum_lft = min_t(u32,
+				stored_lft, MIN_VALID_LIFETIME);
+			valid_lft = max(valid_lft, minimum_lft);
+
+			/* RFC4862 Section 5.5.3e:
+			 * "Note that the preferred lifetime of the
+			 *  corresponding address is always reset to
+			 *  the Preferred Lifetime in the received
+			 *  Prefix Information option, regardless of
+			 *  whether the valid lifetime is also reset or
+			 *  ignored."
+			 *
+			 * So we should always update prefered_lft here.
+			 */
+			update_lft = 1;
+		}
+
+		if (update_lft) {
+			ifp->valid_lft = valid_lft;
+			ifp->prefered_lft = prefered_lft;
+			ifp->tstamp = now;
+			flags = ifp->flags;
+			ifp->flags &= ~IFA_F_DEPRECATED;
+			spin_unlock_bh(&ifp->lock);
+
+			if (!(flags&IFA_F_TENTATIVE))
+				ipv6_ifa_notify(0, ifp);
+		} else
+			spin_unlock_bh(&ifp->lock);
+
+		manage_tempaddrs(in6_dev, ifp, valid_lft, prefered_lft,
+				 create, now);
+
+		in6_ifa_put(ifp);
+		addrconf_verify();
+	}
+
+	return 0;
+}
+
 void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 {
 	struct prefix_info *pinfo;
 	__u32 valid_lft;
 	__u32 prefered_lft;
-	int addr_type;
+	int addr_type, err;
 	u32 addr_flags = 0;
 	struct inet6_dev *in6_dev;
 	struct net *net = dev_net(dev);
@@ -2432,9 +2530,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 	/* Try to figure out our local address for this prefix */
 
 	if (pinfo->autoconf && in6_dev->cnf.autoconf) {
-		struct inet6_ifaddr *ifp;
 		struct in6_addr addr;
-		int create = 0, update_lft = 0;
 		bool tokenized = false;
 
 		if (pinfo->prefix_len == 64) {
@@ -2453,106 +2549,25 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 				goto ok;
 			} else if (ipv6_generate_eui64(addr.s6_addr + 8, dev) &&
 				   ipv6_inherit_eui64(addr.s6_addr + 8, in6_dev)) {
-				in6_dev_put(in6_dev);
-				return;
+				goto put;
 			}
 			goto ok;
 		}
 		net_dbg_ratelimited("IPv6 addrconf: prefix with wrong length %d\n",
 				    pinfo->prefix_len);
-		in6_dev_put(in6_dev);
-		return;
+		goto put;
 
 ok:
-
-		ifp = ipv6_get_ifaddr(net, &addr, dev, 1);
-
-		if (!ifp && valid_lft) {
-			int max_addresses = in6_dev->cnf.max_addresses;
-
-#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
-			if (in6_dev->cnf.optimistic_dad &&
-			    !net->ipv6.devconf_all->forwarding && sllao)
-				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.
-			 */
-			if (!max_addresses ||
-			    ipv6_count_addresses(in6_dev) < max_addresses)
-				ifp = ipv6_add_addr(in6_dev, &addr, NULL,
-						    pinfo->prefix_len,
-						    addr_type&IPV6_ADDR_SCOPE_MASK,
-						    addr_flags, valid_lft,
+		err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
+						   &addr, addr_type,
+						   addr_flags, sllao,
+						   tokenized, valid_lft,
 						   prefered_lft);
-
-			if (IS_ERR_OR_NULL(ifp)) {
-				in6_dev_put(in6_dev);
-				return;
-			}
-
-			update_lft = 0;
-			create = 1;
-			spin_lock_bh(&ifp->lock);
-			ifp->flags |= IFA_F_MANAGETEMPADDR;
-			ifp->cstamp = jiffies;
-			ifp->tokenized = tokenized;
-			spin_unlock_bh(&ifp->lock);
-			addrconf_dad_start(ifp);
-		}
-
-		if (ifp) {
-			u32 flags;
-			unsigned long now;
-			u32 stored_lft;
-
-			/* update lifetime (RFC2462 5.5.3 e) */
-			spin_lock_bh(&ifp->lock);
-			now = jiffies;
-			if (ifp->valid_lft > (now - ifp->tstamp) / HZ)
-				stored_lft = ifp->valid_lft - (now - ifp->tstamp) / HZ;
-			else
-				stored_lft = 0;
-			if (!update_lft && !create && stored_lft) {
-				const u32 minimum_lft = min_t(u32,
-					stored_lft, MIN_VALID_LIFETIME);
-				valid_lft = max(valid_lft, minimum_lft);
-
-				/* RFC4862 Section 5.5.3e:
-				 * "Note that the preferred lifetime of the
-				 *  corresponding address is always reset to
-				 *  the Preferred Lifetime in the received
-				 *  Prefix Information option, regardless of
-				 *  whether the valid lifetime is also reset or
-				 *  ignored."
-				 *
-				 * So we should always update prefered_lft here.
-				 */
-				update_lft = 1;
-			}
-
-			if (update_lft) {
-				ifp->valid_lft = valid_lft;
-				ifp->prefered_lft = prefered_lft;
-				ifp->tstamp = now;
-				flags = ifp->flags;
-				ifp->flags &= ~IFA_F_DEPRECATED;
-				spin_unlock_bh(&ifp->lock);
-
-				if (!(flags&IFA_F_TENTATIVE))
-					ipv6_ifa_notify(0, ifp);
-			} else
-				spin_unlock_bh(&ifp->lock);
-
-			manage_tempaddrs(in6_dev, ifp, valid_lft, prefered_lft,
-					 create, now);
-
-			in6_ifa_put(ifp);
-			addrconf_verify();
-		}
+		if (err)
+			goto put;
 	}
 	inet6_prefix_notify(RTM_NEWPREFIX, in6_dev, pinfo);
+put:
 	in6_dev_put(in6_dev);
 }