rework IPv6 dns address selection (FS#635)

Don't return anymore the link local IPv6 address as DNS IPv6 address
since different OS implementations (e.g. android, ...) cannot handle
a link local IPv6 address as DNS address.

IPv6 DNS address selection is reworked as follows :
-Consider all global/ULA IPv6 address having a valid lifetime
-Give preference to global/ULA IPv6 addresses being not deprecated
-Give preference to ULA IPv6 addresses over IPv6 global addresses
-Give preference to the IPv6 address with the longest preferred lifetime in
its selected category (ULA or global)
-If no global/ULA IPv6 address is present use the IPv6 link local address

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 4cd9e02..ebb0c80 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -232,7 +232,7 @@ static void handle_client_request(void *addr, void *data, size_t len,
 	size_t dns_cnt = iface->dns_cnt;
 
 	if ((dns_cnt == 0) &&
-		!odhcpd_get_linklocal_interface_address(iface->ifindex, &dns_addr)) {
+		!odhcpd_get_interface_dns_addr(iface, &dns_addr)) {
 		dns_addr_ptr = &dns_addr;
 		dns_cnt = 1;
 	}
@@ -464,7 +464,7 @@ static void relay_server_response(uint8_t *data, size_t len)
 		size_t rewrite_cnt = iface->dns_cnt;
 
 		if (rewrite_cnt == 0) {
-			if (odhcpd_get_linklocal_interface_address(iface->ifindex, &addr))
+			if (odhcpd_get_interface_dns_addr(iface, &addr))
 				return; // Unable to get interface address
 
 			rewrite = &addr;