Merge pull request #21692 from yuwata/network-wireguard-allow-to-start-ndisc-or-radv

network: wireguard: allow to start ndisc or radv

src/network/networkd-address.c

@@ -600,7 +600,7 @@ const char* format_lifetime(char *buf, size_t l, usec_t lifetime_usec) {
 }
 
 static void log_address_debug(const Address *address, const char *str, const Link *link) {
-        _cleanup_free_ char *state = NULL, *addr = NULL, *peer = NULL, *flags_str = NULL;
+        _cleanup_free_ char *state = NULL, *addr = NULL, *peer = NULL, *flags_str = NULL, *scope_str = NULL;
 
         assert(address);
         assert(str);
@@ -615,13 +615,14 @@ static void log_address_debug(const Address *address, const char *str, const Lin
                 (void) in_addr_to_string(address->family, &address->in_addr_peer, &peer);
 
         (void) address_flags_to_string_alloc(address->flags, address->family, &flags_str);
+        (void) route_scope_to_string_alloc(address->scope, &scope_str);
 
-        log_link_debug(link, "%s %s address (%s): %s%s%s/%u (valid %s, preferred %s), flags: %s",
+        log_link_debug(link, "%s %s address (%s): %s%s%s/%u (valid %s, preferred %s), flags: %s, scope: %s",
                        str, strna(network_config_source_to_string(address->source)), strna(state),
                        strnull(addr), peer ? " peer " : "", strempty(peer), address->prefixlen,
                        FORMAT_LIFETIME(address->lifetime_valid_usec),
                        FORMAT_LIFETIME(address->lifetime_preferred_usec),
-                       strna(flags_str));
+                       strna(flags_str), strna(scope_str));
 }
 
 static int address_set_netlink_message(const Address *address, sd_netlink_message *req, Link *link) {
@@ -751,7 +752,7 @@ int link_drop_ipv6ll_addresses(Link *link) {
         /* IPv6LL address may be in the tentative state, and in that case networkd has not received it.
          * So, we need to dump all IPv6 addresses. */
 
-        if (link_ipv6ll_enabled(link))
+        if (link_may_have_ipv6ll(link))
                 return 0;
 
         r = sd_rtnl_message_new_addr(link->manager->rtnl, &req, RTM_GETADDR, link->ifindex, AF_INET6);
@@ -1916,18 +1917,11 @@ static int address_section_verify(Address *address) {
                 address->label = mfree(address->label);
         }
 
-        if (in_addr_is_localhost(address->family, &address->in_addr) > 0 &&
-            (address->family == AF_INET || !address->scope_set)) {
-                /* For IPv4, scope must be always RT_SCOPE_HOST.
-                 * For IPv6, use RT_SCOPE_HOST only when it is not explicitly specified. */
-
-                if (address->scope_set && address->scope != RT_SCOPE_HOST)
-                        log_warning_errno(SYNTHETIC_ERRNO(EINVAL),
-                                          "%s: non-host scope is set for localhost address. "
-                                          "Ignoring Scope= setting in the [Address] section from line %u. ",
-                                          address->section->filename, address->section->line);
-
-                address->scope = RT_SCOPE_HOST;
+        if (!address->scope_set) {
+                if (in_addr_is_localhost(address->family, &address->in_addr) > 0)
+                        address->scope = RT_SCOPE_HOST;
+                else if (in_addr_is_link_local(address->family, &address->in_addr) > 0)
+                        address->scope = RT_SCOPE_LINK;
         }
 
         if (address->family == AF_INET6 &&

src/network/networkd-link.c

@@ -126,6 +126,43 @@ bool link_ipv6ll_enabled(Link *link) {
         return link->network->link_local & ADDRESS_FAMILY_IPV6;
 }
 
+bool link_may_have_ipv6ll(Link *link) {
+        assert(link);
+
+        /*
+         * This is equivalent to link_ipv6ll_enabled() for non-WireGuard interfaces.
+         *
+         * For WireGuard interface, the kernel does not assign any IPv6LL addresses, but we can assign
+         * it manually. It is necessary to set an IPv6LL address manually to run NDisc or RADV on
+         * WireGuard interface. Note, also Multicast=yes must be set. See #17380.
+         *
+         * TODO: May be better to introduce GenerateIPv6LinkLocalAddress= setting, and use algorithms
+         *       used in networkd-address-generation.c
+         */
+
+        if (link_ipv6ll_enabled(link))
+                return true;
+
+        /* IPv6LL address can be manually assigned on WireGuard interface. */
+        if (streq_ptr(link->kind, "wireguard")) {
+                Address *a;
+
+                if (!link->network)
+                        return false;
+
+                ORDERED_HASHMAP_FOREACH(a, link->network->addresses_by_section) {
+                        if (a->family != AF_INET6)
+                                continue;
+                        if (in6_addr_is_set(&a->in_addr_peer.in6))
+                                continue;
+                        if (in6_addr_is_link_local(&a->in_addr.in6))
+                                return true;
+                }
+        }
+
+        return false;
+}
+
 bool link_ipv6_enabled(Link *link) {
         assert(link);
 

src/network/networkd-link.h

@@ -215,6 +215,7 @@ bool link_has_carrier(Link *link);
 
 bool link_ipv6_enabled(Link *link);
 bool link_ipv6ll_enabled(Link *link);
+bool link_may_have_ipv6ll(Link *link);
 int link_ipv6ll_gained(Link *link);
 
 bool link_ipv4ll_enabled(Link *link);

src/network/networkd-ndisc.c

@@ -37,7 +37,7 @@ bool link_ipv6_accept_ra_enabled(Link *link) {
         if (!link->network)
                 return false;
 
-        if (!link_ipv6ll_enabled(link))
+        if (!link_may_have_ipv6ll(link))
                 return false;
 
         assert(link->network->ipv6_accept_ra >= 0);

src/network/networkd-radv.c

@@ -54,7 +54,7 @@ void network_adjust_radv(Network *network) {
 bool link_radv_enabled(Link *link) {
         assert(link);
 
-        if (!link_ipv6ll_enabled(link))
+        if (!link_may_have_ipv6ll(link))
                 return false;
 
         return link->network->router_prefix_delegation;