[IPV6] ADDRCONF: Mobile IPv6 Home Address support.

IFA_F_HOMEADDRESS is introduced for Mobile IPv6 Home Addresses on
Mobile Node.

The IFA_F_HOMEADDRESS flag should be set for Mobile IPv6 Home
Addresses for 2 purposes. 1) We need to check this on receipt of
Type 2 Routing Header (RFC3775 Secion 6.4), 2) We prefer Home
Address(es) in source address selection (RFC3484 Section 5 Rule 4).

Signed-off-by: Noriaki TAKAMIYA <takamiya@po.ntts.co.jp>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 43 insertions, 8 deletions

diff --git a/include/linux/if_addr.h b/include/linux/if_addr.h
index ca24b9de13fb..dbe8f6120a40 100644
--- a/include/linux/if_addr.h
+++ b/include/linux/if_addr.h
@@ -39,6 +39,7 @@ enum
 #define IFA_F_TEMPORARY         IFA_F_SECONDARY
 
 #define IFA_F_NODAD             0x02
+#define IFA_F_HOMEADDRESS       0x10
 #define IFA_F_DEPRECATED        0x20
 #define IFA_F_TENTATIVE         0x40
 #define IFA_F_PERMANENT         0x80
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index aa2ed8f0a9dd..44f1b673f916 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -61,12 +61,8 @@ extern int			addrconf_set_dstaddr(void __user *arg);
 extern int                      ipv6_chk_addr(struct in6_addr *addr,
                                               struct net_device *dev,
                                               int strict);
-/* XXX: this is a placeholder till addrconf supports */
 #ifdef CONFIG_IPV6_MIP6
-static inline int ipv6_chk_home_addr(struct in6_addr *addr)
-{
-        return 0;
-}
+extern int                      ipv6_chk_home_addr(struct in6_addr *addr);
 #endif
 extern struct inet6_ifaddr *    ipv6_get_ifaddr(struct in6_addr *addr,
                                                 struct net_device *dev,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index adb583a26151..c18676352397 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1038,9 +1038,27 @@ int ipv6_dev_get_saddr(struct net_device *daddr_dev,
                                         continue;
                         }
 
-                        /* Rule 4: Prefer home address -- not implemented yet */
+                        /* Rule 4: Prefer home address */
+#ifdef CONFIG_IPV6_MIP6
+                        if (hiscore.rule < 4) {
+                                if (ifa_result->flags & IFA_F_HOMEADDRESS)
+                                        hiscore.attrs |= IPV6_SADDR_SCORE_HOA;
+                                hiscore.rule++;
+                        }
+                        if (ifa->flags & IFA_F_HOMEADDRESS) {
+                                score.attrs |= IPV6_SADDR_SCORE_HOA;
+                                if (!(ifa_result->flags & IFA_F_HOMEADDRESS)) {
+                                        score.rule = 4;
+                                        goto record_it;
+                                }
+                        } else {
+                                if (hiscore.attrs & IPV6_SADDR_SCORE_HOA)
+                                        continue;
+                        }
+#else
                         if (hiscore.rule < 4)
                                 hiscore.rule++;
+#endif
 
                         /* Rule 5: Prefer outgoing interface */
                         if (hiscore.rule < 5) {
@@ -2759,6 +2777,26 @@ void if6_proc_exit(void)
 }
 #endif  /* CONFIG_PROC_FS */
 
+#ifdef CONFIG_IPV6_MIP6
+/* Check if address is a home address configured on any interface. */
+int ipv6_chk_home_addr(struct in6_addr *addr)
+{
+        int ret = 0;
+        struct inet6_ifaddr * ifp;
+        u8 hash = ipv6_addr_hash(addr);
+        read_lock_bh(&addrconf_hash_lock);
+        for (ifp = inet6_addr_lst[hash]; ifp; ifp = ifp->lst_next) {
+                if (ipv6_addr_cmp(&ifp->addr, addr) == 0 &&
+                    (ifp->flags & IFA_F_HOMEADDRESS)) {
+                        ret = 1;
+                        break;
+                }
+        }
+        read_unlock_bh(&addrconf_hash_lock);
+        return ret;
+}
+#endif
+
 /*
  *      Periodic address status verification
  */
@@ -2930,7 +2968,7 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u8 ifa_flags,
                 prefered_lft = 0x7FFFFFFF/HZ;
 
         spin_lock_bh(&ifp->lock);
-        ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD)) | ifa_flags;
+        ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS)) | ifa_flags;
         ifp->tstamp = jiffies;
         ifp->valid_lft = valid_lft;
         ifp->prefered_lft = prefered_lft;
@@ -2981,7 +3019,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
                 return -ENODEV;
 
         /* We ignore other flags so far. */
-        ifa_flags = ifm->ifa_flags & IFA_F_NODAD;
+        ifa_flags = ifm->ifa_flags & (IFA_F_NODAD | IFA_F_HOMEADDRESS);
 
         ifa = ipv6_get_ifaddr(pfx, dev, 1);
         if (ifa == NULL) {