[IPV6]: Fix source address selection.

Two additional labels (RFC 3484, sec. 10.3) for IPv6 addreses
are defined to make a distinction between global unicast
addresses and Unique Local Addresses (fc00::/7, RFC 4193) and
Teredo (2001::/32, RFC 4380). It is necessary to avoid attempts
of connection that would either fail (eg. fec0:: to 2001:feed::)
or be sub-optimal (2001:0:: to 2001:feed::).

Signed-off-by: Łukasz Stelmach <stlman@poczta.fm>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c2c26fa0943d..6b361fc3e14d 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -862,6 +862,8 @@ static int inline ipv6_saddr_label(const struct in6_addr *addr, int type)
   *     2002::/16               2
   *     ::/96                   3
   *     ::ffff:0:0/96           4
+  *     fc00::/7                5
+  *     2001::/32               6
   */
         if (type & IPV6_ADDR_LOOPBACK)
                 return 0;
@@ -869,8 +871,12 @@ static int inline ipv6_saddr_label(const struct in6_addr *addr, int type)
                 return 3;
         else if (type & IPV6_ADDR_MAPPED)
                 return 4;
+        else if (addr->s6_addr32[0] == htonl(0x20010000))
+                return 6;
         else if (addr->s6_addr16[0] == htons(0x2002))
                 return 2;
+        else if ((addr->s6_addr[0] & 0xfe) == 0xfc)
+                return 5;
         return 1;
 }