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

Don't generate an IPv6 prefix address without taking into account the
interface state. In case eui64 is configured to generate the ifaceid this
could fail as the layer3 device mac address could not yet be available if
the interface is not yet in setup or up state.
While at it remove the interface metric assignment as this is already done
by the function interface_set_route_info.

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

diff --git a/interface-ip.c b/interface-ip.c
index 1490ca4a7aa3302a22284f3b58413772c1a524cf..716a093e80a58afd753e80ed429b8ac3931d0d0e 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)) {