Revert "networkd: ndisc - revert to letting the kernel handle NDisc"

This reverts commit 23f186494c.

The bug has now been fixed, so we can go back to managing this ourselves.

src/network/networkd-ndisc.c

@@ -26,7 +26,7 @@
 #include "sd-ndisc.h"
 
 #include "networkd-link.h"
-/*
+
 static int ndisc_netlink_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
         _cleanup_link_unref_ Link *link = userdata;
         int r;
@@ -77,6 +77,7 @@ static void ndisc_prefix_autonomous_handler(sd_ndisc *nd, const struct in6_addr
         if (in_addr_is_null(AF_INET6, (const union in_addr_union *) &link->network->ipv6_token) == 0)
                 memcpy(((char *)&address->in_addr.in6) + 8, ((char *)&link->network->ipv6_token) + 8, 8);
         else {
+                /* see RFC4291 section 2.5.1 */
                 address->in_addr.in6.__in6_u.__u6_addr8[8]  = link->mac.ether_addr_octet[0];
                 address->in_addr.in6.__in6_u.__u6_addr8[8] ^= 1 << 1;
                 address->in_addr.in6.__in6_u.__u6_addr8[9]  = link->mac.ether_addr_octet[1];
@@ -139,12 +140,11 @@ static void ndisc_prefix_onlink_handler(sd_ndisc *nd, const struct in6_addr *pre
 
         link->ndisc_messages ++;
 }
-*/
 
 static void ndisc_router_handler(sd_ndisc *nd, uint8_t flags, const struct in6_addr *gateway, unsigned lifetime, int pref, void *userdata) {
         _cleanup_route_free_ Route *route = NULL;
         Link *link = userdata;
-        /* usec_t time_now; */
+        usec_t time_now;
         int r;
 
         assert(link);
@@ -163,8 +163,6 @@ static void ndisc_router_handler(sd_ndisc *nd, uint8_t flags, const struct in6_a
                         log_link_warning_errno(link, r, "Starting DHCPv6 client on NDisc request failed: %m");
         }
 
-        return;
-/*
         if (!gateway)
                 return;
 
@@ -191,7 +189,6 @@ static void ndisc_router_handler(sd_ndisc *nd, uint8_t flags, const struct in6_a
         }
 
         link->ndisc_messages ++;
-*/
 }
 
 static void ndisc_handler(sd_ndisc *nd, int event, void *userdata) {
@@ -245,8 +242,8 @@ int ndisc_configure(Link *link) {
 
         r = sd_ndisc_set_callback(link->ndisc_router_discovery,
                                   ndisc_router_handler,
-                                  NULL,
-                                  NULL,
+                                  ndisc_prefix_onlink_handler,
+                                  ndisc_prefix_autonomous_handler,
                                   ndisc_handler,
                                   link);