dhcpv6: prefer ula over other globals

diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index ffcb6df..f850b02 100644 (file)
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -254,15 +254,17 @@ void dhcpv6_write_statefile(void)
                                        struct in6_addr addr;
                                        struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
                                        size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
-                                       size_t mostpref = 0;
+                                       size_t m = 0;
 
                                        for (size_t i = 0; i < addrlen; ++i)
-                                               if (addrs[i].preferred > addrs[mostpref].preferred)
-                                                       mostpref = i;
+                                               if (addrs[i].preferred > addrs[m].preferred ||
+                                                               (addrs[i].preferred == addrs[m].preferred &&
+                                                                               memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
+                                                       m = i;
 
                                        for (size_t i = 0; i < addrlen; ++i) {
                                                if (addrs[i].prefix > 96 || c->valid_until <= now ||
-                                                               (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != mostpref))
+                                                               (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m))
                                                        continue;
 
                                                addr = addrs[i].addr;
@@ -716,11 +718,13 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 
                        struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
                        size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
-                       size_t mostpref = 0;
+                       size_t m = 0;
 
                        for (size_t i = 0; i < addrlen; ++i)
-                               if (addrs[i].preferred > addrs[mostpref].preferred)
-                                       mostpref = i;
+                               if (addrs[i].preferred > addrs[m].preferred ||
+                                               (addrs[i].preferred == addrs[m].preferred &&
+                                                               memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
+                                       m = i;
 
                        for (size_t i = 0; i < addrlen; ++i) {
                                uint32_t prefix_pref = addrs[i].preferred - now;
@@ -760,7 +764,7 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
                                        n.addr.s6_addr32[3] = htonl(a->assigned);
                                        size_t entrlen = sizeof(n) - 4;
 
-                                       if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != mostpref)
+                                       if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m)
                                                continue;
 
                                        if (datalen + entrlen + 4 > buflen || a->assigned == 0)