[PATCH net 1/2] ipv6: add ipv6_dev_find()

[Xin Long]

This is to add an ip_dev_find like function for ipv6, used to find
the dev by saddr.

It will be used by TIPC protocol. So also export it.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/net/addrconf.h |  2 ++
 net/ipv6/addrconf.c    | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 8418b7d..ba3f6c15 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -97,6 +97,8 @@ bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
 
 int ipv6_chk_prefix(const struct in6_addr *addr, struct net_device *dev);
 
+struct net_device *ipv6_dev_find(struct net *net, const struct in6_addr *addr);
+
 struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net,
                                     const struct in6_addr *addr,
                                     struct net_device *dev, int strict);
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 840bfdb..857d6f9 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1983,6 +1983,45 @@ int ipv6_chk_prefix(const struct in6_addr *addr, struct 
net_device *dev)
 }
 EXPORT_SYMBOL(ipv6_chk_prefix);
 
+/**
+ * ipv6_dev_find - find the first device with a given source address.
+ * @net: the net namespace
+ * @addr: the source address
+ *
+ * The caller should be protected by RCU, or RTNL.
+ */
+struct net_device *ipv6_dev_find(struct net *net, const struct in6_addr *addr)
+{
+       unsigned int hash = inet6_addr_hash(net, addr);
+       struct inet6_ifaddr *ifp, *result = NULL;
+       struct net_device *dev = NULL;
+
+       rcu_read_lock();
+       hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
+               if (net_eq(dev_net(ifp->idev->dev), net) &&
+                   ipv6_addr_equal(&ifp->addr, addr)) {
+                       result = ifp;
+                       break;
+               }
+       }
+
+       if (!result) {
+               struct rt6_info *rt;
+
+               rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
+               if (rt) {
+                       dev = rt->dst.dev;
+                       ip6_rt_put(rt);
+               }
+       } else {
+               dev = result->idev->dev;
+       }
+       rcu_read_unlock();
+
+       return dev;
+}
+EXPORT_SYMBOL(ipv6_dev_find);
+
 struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr 
*addr,
                                     struct net_device *dev, int strict)
 {
-- 
2.1.0