interface-ip: fix race condition in IPv6 prefix address generation

[project/netifd.git] / interface-ip.c

diff --git a/interface-ip.c b/interface-ip.c
index 1490ca4..716a093 100644 (file)
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -761,15 +761,7 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
        memset(&addr, 0, sizeof(addr));
        memset(&route, 0, sizeof(route));
 
-       if (IN6_IS_ADDR_UNSPECIFIED(&assignment->addr)) {
-               addr.addr.in6 = prefix->addr;
-               addr.addr.in6.s6_addr32[1] |= htonl(assignment->assigned);
-               generate_ifaceid(iface, &addr.addr.in6);
-               assignment->addr = addr.addr.in6;
-       }
-       else
-               addr.addr.in6 = assignment->addr;
-
+       addr.addr.in6 = assignment->addr;
        addr.mask = assignment->length;
        addr.flags = DEVADDR_INET6 | DEVADDR_OFFLINK;
        addr.preferred_until = prefix->preferred_until;
@@ -778,11 +770,10 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
        route.flags = DEVADDR_INET6;
        route.mask = addr.mask < 64 ? 64 : addr.mask;
        route.addr = addr.addr;
-       clear_if_addr(&route.addr, route.mask);
-       interface_set_route_info(iface, &route);
 
        if (!add && assignment->enabled) {
                time_t now = system_get_rtime();
+
                addr.preferred_until = now;
                if (!addr.valid_until || addr.valid_until - now > 7200)
                        addr.valid_until = now + 7200;
@@ -800,12 +791,24 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
                                                        addr.mask, 0, iface, "unreachable", true);
                }
 
+               clear_if_addr(&route.addr, route.mask);
+               interface_set_route_info(iface, &route);
+
                system_del_route(l3_downlink, &route);
                system_add_address(l3_downlink, &addr);
 
                assignment->enabled = false;
-       } else if (add && (iface->state == IFS_UP || iface->state == IFS_SETUP) &&
-                       !system_add_address(l3_downlink, &addr)) {
+       } else if (add && (iface->state == IFS_UP || iface->state == IFS_SETUP)) {
+               if (IN6_IS_ADDR_UNSPECIFIED(&addr.addr.in6)) {
+                       addr.addr.in6 = prefix->addr;
+                       addr.addr.in6.s6_addr32[1] |= htonl(assignment->assigned);
+                       generate_ifaceid(iface, &addr.addr.in6);
+                       assignment->addr = addr.addr.in6;
+                       route.addr = addr.addr;
+               }
+
+               if (system_add_address(l3_downlink, &addr))
+                       return;
 
                if (!assignment->enabled) {
                        if (iface->ip6table)
@@ -822,7 +825,9 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
                        }
                }
 
-               route.metric = iface->metric;
+               clear_if_addr(&route.addr, route.mask);
+               interface_set_route_info(iface, &route);
+
                system_add_route(l3_downlink, &route);
 
                if (uplink && uplink->l3_dev.dev && !(l3_downlink->settings.flags & DEV_OPT_MTU6)) {