ip6: Implement IPv6 address sharing

This allows the same IPv6 address to exist on more than one
interface. Whenever dhcpcd address an IPv6 address, it will
advertise it along with the hardware address of the preferred
interface.

This is heavliy reliant on the kernel supporting this as it's the
kernel that handle the Duplicate Address Detection.
In a nutshell it needs to support RFC 7527 and ignore NA packets
from any hardware address the host owns.

Currently the only known kernel that fully supports this is
NetBSD-8.99.27

1 files changed, 1 insertions, 0 deletions

diff --git a/src/if.h b/src/if.h
index 51ef75c0..d260d2d1 100644
--- a/src/if.h
+++ b/src/if.h
@@ -197,6 +197,7 @@ int ip6_temp_valid_lifetime(const char *ifname);
 #else
 #define ip6_use_tempaddr(a) (0)
 #endif
+int ip6_forwarding(const char *ifname);
 
 int if_address6(unsigned char, const struct ipv6_addr *);
 int if_addrflags6(const struct interface *, const struct in6_addr *,