Merge pull request #20377 from yuwata/network-bridge-fdb-20305

network: always append new bridge FDB entries

man/systemd.network.xml

@@ -2382,12 +2382,12 @@ IPv6Token=prefixstable:2002:da8:1::</programlisting></para>
 
       <varlistentry>
         <term><varname>UplinkInterface=</varname></term>
-        <listitem><para>Specifies name or index of uplink interface, or one of the special values
+        <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
-        <literal>:none</literal> and <literal>:auto</literal>. When emitting DNS, NTP, or SIP servers
+        values <literal>:none</literal> and <literal>:auto</literal>. When emitting DNS, NTP, or SIP
-        are enabled but no servers are specified, the servers configured in the uplink interface will
+        servers is enabled but no servers are specified, the servers configured in the uplink interface
-        be emitted. When <literal>:auto</literal>, the link which has default gateway with higher
+        will be emitted. When <literal>:auto</literal>, the link which has a default gateway with the
-        priority will be automatically selected. When <literal>:none</literal>, no uplink interface
+        highest priority will be automatically selected. When <literal>:none</literal>, no uplink
-        will be selected. Defaults to <literal>:auto</literal>.</para></listitem>
+        interface will be selected. Defaults to <literal>:auto</literal>.</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -2586,18 +2586,28 @@ IPv6Token=prefixstable:2002:da8:1::</programlisting></para>
         for details. Defaults to <literal>medium</literal>.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>UplinkInterface=</varname></term>
+        <listitem><para>Specifies the name or the index of the uplink interface, or one of the special
+        values <literal>:none</literal> and <literal>:auto</literal>. When emitting DNS servers or
+        search domains is enabled but no servers are specified, the servers configured in the uplink
+        interface will be emitted. When <literal>:auto</literal>, the link which has a default gateway
+        with the highest priority will be automatically selected. When <literal>:none</literal>, no
+        uplink interface will be selected. Defaults to <literal>:auto</literal>.</para></listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>EmitDNS=</varname></term>
         <term><varname>DNS=</varname></term>
 
-        <listitem><para><varname>DNS=</varname> specifies a list of recursive DNS server IPv6 addresses that
+        <listitem><para><varname>DNS=</varname> specifies a list of recursive DNS server IPv6 addresses
-        are distributed via Router Advertisement messages when <varname>EmitDNS=</varname> is
+        that are distributed via Router Advertisement messages when <varname>EmitDNS=</varname> is true.
-        true. <varname>DNS=</varname> also takes special value <literal>_link_local</literal>; in that case
+        <varname>DNS=</varname> also takes special value <literal>_link_local</literal>; in that case
-        the IPv6 link local address is distributed. If <varname>DNS=</varname> is empty, DNS servers are read
+        the IPv6 link local address is distributed. If <varname>DNS=</varname> is empty, DNS servers are
-        from the [Network] section. If the [Network] section does not contain any DNS servers either, DNS
+        read from the [Network] section. If the [Network] section does not contain any DNS servers
-        servers from the uplink with the highest priority default route are used. When
+        either, DNS servers from the uplink interface specified in <varname>UplinkInterface=</varname>
-        <varname>EmitDNS=</varname> is false, no DNS server information is sent in Router Advertisement
+        will be used. When <varname>EmitDNS=</varname> is false, no DNS server information is sent in
-        messages. <varname>EmitDNS=</varname> defaults to true.</para></listitem>
+        Router Advertisement messages. <varname>EmitDNS=</varname> defaults to true.</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -2605,11 +2615,12 @@ IPv6Token=prefixstable:2002:da8:1::</programlisting></para>
         <term><varname>Domains=</varname></term>
 
         <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when
-        <varname>EmitDomains=</varname> is true. If <varname>Domains=</varname> is empty, DNS search domains
+        <varname>EmitDomains=</varname> is true. If <varname>Domains=</varname> is empty, DNS search
-        are read from the [Network] section. If the [Network] section does not contain any DNS search domains
+        domains are read from the [Network] section. If the [Network] section does not contain any DNS
-        either, DNS search domains from the uplink with the highest priority default route are used. When
+        search domains either, DNS search domains from the uplink interface specified in
-        <varname>EmitDomains=</varname> is false, no DNS search domain information is sent in Router
+        <varname>UplinkInterface=</varname> will be used. When <varname>EmitDomains=</varname> is false,
-        Advertisement messages. <varname>EmitDomains=</varname> defaults to true.</para></listitem>
+        no DNS search domain information is sent in Router Advertisement messages.
+        <varname>EmitDomains=</varname> defaults to true.</para></listitem>
       </varlistentry>
 
       <varlistentry>

src/libsystemd/sd-netlink/rtnl-message.c

@@ -443,8 +443,12 @@ int sd_rtnl_message_new_neigh(sd_netlink *rtnl, sd_netlink_message **ret, uint16
         if (r < 0)
                 return r;
 
-        if (nlmsg_type == RTM_NEWNEIGH)
+        if (nlmsg_type == RTM_NEWNEIGH) {
-                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+                if (ndm_family == AF_BRIDGE)
+                        (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_APPEND;
+                else
+                        (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+        }
 
         ndm = NLMSG_DATA((*ret)->hdr);
 

src/network/networkd-dhcp-server.c

@@ -106,7 +106,7 @@ static int dhcp_server_find_uplink(Link *link, Link **ret) {
         if (link->network->dhcp_server_uplink_index > 0)
                 return link_get_by_index(link->manager, link->network->dhcp_server_uplink_index, ret);
 
-        if (link->network->dhcp_server_uplink_index == 0) {
+        if (link->network->dhcp_server_uplink_index == UPLINK_INDEX_AUTO) {
                 /* It is not necessary to propagate error in automatic selection. */
                 if (manager_find_uplink(link->manager, AF_INET, link, ret) < 0)
                         *ret = NULL;
@@ -663,55 +663,3 @@ int config_parse_dhcp_server_address(
         network->dhcp_server_address_prefixlen = prefixlen;
         return 0;
 }
-
-int config_parse_dhcp_server_uplink(
-                const char *unit,
-                const char *filename,
-                unsigned line,
-                const char *section,
-                unsigned section_line,
-                const char *lvalue,
-                int ltype,
-                const char *rvalue,
-                void *data,
-                void *userdata) {
-
-        Network *network = userdata;
-        int r;
-
-        assert(filename);
-        assert(lvalue);
-        assert(rvalue);
-
-        if (isempty(rvalue) || streq(rvalue, ":auto")) {
-                network->dhcp_server_uplink_index = 0; /* uplink will be selected automatically */
-                network->dhcp_server_uplink_name = mfree(network->dhcp_server_uplink_name);
-                return 0;
-        }
-
-        if (streq(rvalue, ":none")) {
-                network->dhcp_server_uplink_index = -1; /* uplink will not be selected automatically */
-                network->dhcp_server_uplink_name = mfree(network->dhcp_server_uplink_name);
-                return 0;
-        }
-
-        r = parse_ifindex(rvalue);
-        if (r > 0) {
-                network->dhcp_server_uplink_index = r;
-                network->dhcp_server_uplink_name = mfree(network->dhcp_server_uplink_name);
-                return 0;
-        }
-
-        if (!ifname_valid_full(rvalue, IFNAME_VALID_ALTERNATIVE)) {
-                log_syntax(unit, LOG_WARNING, filename, line, 0,
-                           "Invalid interface name in %s=, ignoring assignment: %s", lvalue, rvalue);
-                return 0;
-        }
-
-        r = free_and_strdup_warn(&network->dhcp_server_uplink_name, rvalue);
-        if (r < 0)
-                return r;
-
-        network->dhcp_server_uplink_index = 0;
-        return 0;
-}

src/network/networkd-dhcp-server.h

@@ -15,4 +15,3 @@ int request_process_dhcp_server(Request *req);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_server_relay_agent_suboption);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_server_emit);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_server_address);
-CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_server_uplink);

src/network/networkd-link.c

@@ -618,12 +618,8 @@ static int link_acquire_dynamic_ipv6_conf(Link *link) {
 
                 log_link_debug(link, "Starting IPv6 Router Advertisements");
 
-                r = radv_emit_dns(link);
-                if (r < 0)
-                        return log_link_warning_errno(link, r, "Failed to configure DNS or Domains in IPv6 Router Advertisement: %m");
-
                 r = sd_radv_start(link->radv);
-                if (r < 0 && r != -EBUSY)
+                if (r < 0)
                         return log_link_warning_errno(link, r, "Could not start IPv6 Router Advertisement: %m");
         }
 
@@ -1147,7 +1143,7 @@ static int link_configure(Link *link) {
         if (r < 0)
                 return r;
 
-        r = radv_configure(link);
+        r = link_request_radv(link);
         if (r < 0)
                 return r;
 

src/network/networkd-network-gperf.gperf

@@ -265,7 +265,7 @@ IPv6AcceptRA.PrefixDenyList,                 config_parse_ndisc_address_filter,
 IPv6AcceptRA.RouteAllowList,                 config_parse_ndisc_address_filter,                        0,                             offsetof(Network, ndisc_allow_listed_route_prefix)
 IPv6AcceptRA.RouteDenyList,                  config_parse_ndisc_address_filter,                        0,                             offsetof(Network, ndisc_deny_listed_route_prefix)
 DHCPServer.ServerAddress,                    config_parse_dhcp_server_address,                         0,                             0
-DHCPServer.UplinkInterface,                  config_parse_dhcp_server_uplink,                          0,                             0
+DHCPServer.UplinkInterface,                  config_parse_uplink,                                      0,                             0
 DHCPServer.RelayTarget,                      config_parse_in_addr_non_null,                            AF_INET,                       offsetof(Network, dhcp_server_relay_target)
 DHCPServer.RelayAgentCircuitId,              config_parse_dhcp_server_relay_agent_suboption,           0,                             offsetof(Network, dhcp_server_relay_agent_circuit_id)
 DHCPServer.RelayAgentRemoteId,               config_parse_dhcp_server_relay_agent_suboption,           0,                             offsetof(Network, dhcp_server_relay_agent_remote_id)
@@ -333,6 +333,7 @@ IPv6SendRA.DNS,                              config_parse_radv_dns,
 IPv6SendRA.EmitDomains,                      config_parse_bool,                                        0,                             offsetof(Network, router_emit_domains)
 IPv6SendRA.Domains,                          config_parse_radv_search_domains,                         0,                             0
 IPv6SendRA.DNSLifetimeSec,                   config_parse_sec,                                         0,                             offsetof(Network, router_dns_lifetime_usec)
+IPv6SendRA.UplinkInterface,                  config_parse_uplink,                                      0,                             0
 IPv6Prefix.Prefix,                           config_parse_prefix,                                      0,                             0
 IPv6Prefix.OnLink,                           config_parse_prefix_flags,                                0,                             0
 IPv6Prefix.AddressAutoconfiguration,         config_parse_prefix_flags,                                0,                             0

src/network/networkd-network.c

@@ -640,6 +640,7 @@ static Network *network_free(Network *network) {
 
         free(network->dhcp_server_timezone);
         free(network->dhcp_server_uplink_name);
+        free(network->router_uplink_name);
 
         for (sd_dhcp_lease_server_type_t t = 0; t < _SD_DHCP_LEASE_SERVER_TYPE_MAX; t++)
                 free(network->dhcp_server_emit[t].addresses);
@@ -1185,6 +1186,73 @@ int config_parse_link_group(
         return 0;
 }
 
+
+int config_parse_uplink(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        Network *network = userdata;
+        int *index, r;
+        char **name;
+
+        assert(filename);
+        assert(section);
+        assert(lvalue);
+        assert(rvalue);
+
+        if (streq(section, "DHCPServer")) {
+                index = &network->dhcp_server_uplink_index;
+                name = &network->dhcp_server_uplink_name;
+        } else if (streq(section, "IPv6SendRA")) {
+                index = &network->router_uplink_index;
+                name = &network->router_uplink_name;
+        } else
+                assert_not_reached();
+
+        if (isempty(rvalue) || streq(rvalue, ":auto")) {
+                *index = UPLINK_INDEX_AUTO;
+                *name = mfree(*name);
+                return 0;
+        }
+
+        if (streq(rvalue, ":none")) {
+                *index = UPLINK_INDEX_NONE;
+                *name = mfree(*name);
+                return 0;
+        }
+
+        r = parse_ifindex(rvalue);
+        if (r > 0) {
+                *index = r;
+                *name = mfree(*name);
+                return 0;
+        }
+
+        if (!ifname_valid_full(rvalue, IFNAME_VALID_ALTERNATIVE)) {
+                log_syntax(unit, LOG_WARNING, filename, line, 0,
+                           "Invalid interface name in %s=, ignoring assignment: %s", lvalue, rvalue);
+                return 0;
+        }
+
+        /* The interface name will be resolved later. */
+        r = free_and_strdup_warn(name, rvalue);
+        if (r < 0)
+                return r;
+
+        /* Note, if uplink_name is set, then uplink_index will be ignored. So, the below does not mean
+         * an uplink interface will be selected automatically. */
+        *index = UPLINK_INDEX_AUTO;
+        return 0;
+}
+
 DEFINE_CONFIG_PARSE_ENUM(config_parse_required_family_for_online, link_required_address_family, AddressFamily,
                          "Failed to parse RequiredFamilyForOnline= setting");
 

src/network/networkd-network.h

@@ -26,6 +26,10 @@
 #include "resolve-util.h"
 #include "socket-netlink.h"
 
+/* Special values for *_uplink_index. */
+#define UPLINK_INDEX_AUTO  0 /* uplink will be selected automatically */
+#define UPLINK_INDEX_NONE -1 /* uplink will not be selected automatically */
+
 typedef enum KeepConfiguration {
         KEEP_CONFIGURATION_NO            = 0,
         KEEP_CONFIGURATION_DHCP_ON_START = 1 << 0,
@@ -224,6 +228,8 @@ struct Network {
         struct in6_addr *router_dns;
         unsigned n_router_dns;
         OrderedSet *router_search_domains;
+        int router_uplink_index;
+        char *router_uplink_name;
 
         /* DHCPv6 Prefix Delegation support */
         int dhcp6_pd;
@@ -364,6 +370,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_keep_configuration);
 CONFIG_PARSER_PROTOTYPE(config_parse_ipv6_link_local_address_gen_mode);
 CONFIG_PARSER_PROTOTYPE(config_parse_activation_policy);
 CONFIG_PARSER_PROTOTYPE(config_parse_link_group);
+CONFIG_PARSER_PROTOTYPE(config_parse_uplink);
 
 const struct ConfigPerfItem* network_network_gperf_lookup(const char *key, GPERF_LEN_TYPE length);
 

src/network/networkd-queue.c

@@ -43,6 +43,8 @@ static void request_free_object(RequestType type, void *object) {
         case REQUEST_TYPE_NEXTHOP:
                 nexthop_free(object);
                 break;
+        case REQUEST_TYPE_RADV:
+                break;
         case REQUEST_TYPE_ROUTE:
                 route_free(object);
                 break;
@@ -110,7 +112,7 @@ static void request_hash_func(const Request *req, struct siphash *state) {
                 trivial_hash_func(req->object, state);
                 break;
         case REQUEST_TYPE_DHCP_SERVER:
-                /* This type does not have object. */
+                /* This type does not have an object. */
                 break;
         case REQUEST_TYPE_IPV6_PROXY_NDP:
                 in6_addr_hash_func(req->ipv6_proxy_ndp, state);
@@ -121,6 +123,9 @@ static void request_hash_func(const Request *req, struct siphash *state) {
         case REQUEST_TYPE_NEXTHOP:
                 nexthop_hash_func(req->nexthop, state);
                 break;
+        case REQUEST_TYPE_RADV:
+                /* This type does not have an object. */
+                break;
         case REQUEST_TYPE_ROUTE:
                 route_hash_func(req->route, state);
                 break;
@@ -174,6 +179,8 @@ static int request_compare_func(const struct Request *a, const struct Request *b
                 return nexthop_compare_func(a->nexthop, b->nexthop);
         case REQUEST_TYPE_ROUTE:
                 return route_compare_func(a->route, b->route);
+        case REQUEST_TYPE_RADV:
+                return 0;
         case REQUEST_TYPE_ROUTING_POLICY_RULE:
                 return routing_policy_rule_compare_func(a->rule, b->rule);
         case REQUEST_TYPE_SET_LINK:
@@ -211,10 +218,14 @@ int link_queue_request(
         assert(IN_SET(type,
                       REQUEST_TYPE_ACTIVATE_LINK,
                       REQUEST_TYPE_DHCP_SERVER,
+                      REQUEST_TYPE_RADV,
                       REQUEST_TYPE_SET_LINK,
                       REQUEST_TYPE_UP_DOWN) ||
                object);
-        assert(type == REQUEST_TYPE_DHCP_SERVER || netlink_handler);
+        assert(IN_SET(type,
+                      REQUEST_TYPE_DHCP_SERVER,
+                      REQUEST_TYPE_RADV) ||
+               netlink_handler);
 
         req = new(Request, 1);
         if (!req) {
@@ -298,6 +309,9 @@ int manager_process_requests(sd_event_source *s, void *userdata) {
                         case REQUEST_TYPE_NEXTHOP:
                                 r = request_process_nexthop(req);
                                 break;
+                        case REQUEST_TYPE_RADV:
+                                r = request_process_radv(req);
+                                break;
                         case REQUEST_TYPE_ROUTE:
                                 r = request_process_route(req);
                                 break;

src/network/networkd-queue.h

@@ -31,6 +31,7 @@ typedef enum RequestType {
         REQUEST_TYPE_IPV6_PROXY_NDP,
         REQUEST_TYPE_NEIGHBOR,
         REQUEST_TYPE_NEXTHOP,
+        REQUEST_TYPE_RADV,
         REQUEST_TYPE_ROUTE,
         REQUEST_TYPE_ROUTING_POLICY_RULE,
         REQUEST_TYPE_SET_LINK,

src/network/networkd-radv.c

@@ -10,6 +10,7 @@
 #include "networkd-link.h"
 #include "networkd-manager.h"
 #include "networkd-network.h"
+#include "networkd-queue.h"
 #include "networkd-radv.h"
 #include "parse-util.h"
 #include "string-util.h"
@@ -583,10 +584,7 @@ static int radv_set_dns(Link *link, Link *uplink) {
                 goto set_dns;
 
         if (uplink) {
-                if (!uplink->network) {
+                assert(uplink->network);
-                        log_link_debug(uplink, "Cannot fetch DNS servers as uplink interface is not managed by us");
-                        return 0;
-                }
 
                 r = network_get_ipv6_dns(uplink->network, &dns, &n_dns);
                 if (r > 0)
@@ -595,7 +593,7 @@ static int radv_set_dns(Link *link, Link *uplink) {
 
         return 0;
 
- set_dns:
+set_dns:
         return sd_radv_set_rdnss(link->radv,
                                  DIV_ROUND_UP(lifetime_usec, USEC_PER_SEC),
                                  dns, n_dns);
@@ -622,10 +620,7 @@ static int radv_set_domains(Link *link, Link *uplink) {
                 goto set_domains;
 
         if (uplink) {
-                if (!uplink->network) {
+                assert(uplink->network);
-                        log_link_debug(uplink, "Cannot fetch DNS search domains as uplink interface is not managed by us");
-                        return 0;
-                }
 
                 search_domains = uplink->network->search_domains;
                 if (search_domains)
@@ -634,7 +629,7 @@ static int radv_set_domains(Link *link, Link *uplink) {
 
         return 0;
 
- set_domains:
+set_domains:
         s = ordered_set_get_strv(search_domains);
         if (!s)
                 return log_oom();
@@ -645,20 +640,23 @@ static int radv_set_domains(Link *link, Link *uplink) {
 
 }
 
-int radv_emit_dns(Link *link) {
+static int radv_find_uplink(Link *link, Link **ret) {
-        Link *uplink = NULL;
+        assert(link);
-        int r;
 
-        (void) manager_find_uplink(link->manager, AF_INET6, link, &uplink);
+        if (link->network->router_uplink_name)
+                return link_get_by_name(link->manager, link->network->router_uplink_name, ret);
 
-        r = radv_set_dns(link, uplink);
+        if (link->network->router_uplink_index > 0)
-        if (r < 0)
+                return link_get_by_index(link->manager, link->network->router_uplink_index, ret);
-                log_link_warning_errno(link, r, "Could not set RA DNS: %m");
 
-        r = radv_set_domains(link, uplink);
+        if (link->network->router_uplink_index == UPLINK_INDEX_AUTO) {
-        if (r < 0)
+                /* It is not necessary to propagate error in automatic selection. */
-                log_link_warning_errno(link, r, "Could not set RA Domains: %m");
+                if (manager_find_uplink(link->manager, AF_INET6, link, ret) < 0)
+                        *ret = NULL;
+                return 0;
+        }
 
+        *ret = NULL;
         return 0;
 }
 
@@ -671,8 +669,9 @@ static bool link_radv_enabled(Link *link) {
         return link->network->router_prefix_delegation;
 }
 
-int radv_configure(Link *link) {
+static int radv_configure(Link *link) {
         uint16_t router_lifetime;
+        Link *uplink = NULL;
         RoutePrefix *q;
         Prefix *p;
         int r;
@@ -680,9 +679,6 @@ int radv_configure(Link *link) {
         assert(link);
         assert(link->network);
 
-        if (!link_radv_enabled(link))
-                return 0;
-
         if (link->radv)
                 return -EBUSY;
 
@@ -748,6 +744,16 @@ int radv_configure(Link *link) {
                         return r;
         }
 
+        (void) radv_find_uplink(link, &uplink);
+
+        r = radv_set_dns(link, uplink);
+        if (r < 0)
+                return log_link_debug_errno(link, r, "Could not set RA DNS: %m");
+
+        r = radv_set_domains(link, uplink);
+        if (r < 0)
+                return log_link_debug_errno(link, r, "Could not set RA Domains: %m");
+
         return 0;
 }
 
@@ -779,6 +785,96 @@ int radv_update_mac(Link *link) {
         return 0;
 }
 
+static int radv_is_ready_to_configure(Link *link) {
+        bool needs_uplink = false;
+        int r;
+
+        assert(link);
+        assert(link->network);
+
+        if (!IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED))
+                return false;
+
+        if (in6_addr_is_null(&link->ipv6ll_address))
+                return false;
+
+        if (link->network->router_emit_dns && !link->network->router_dns) {
+                _cleanup_free_ struct in6_addr *dns = NULL;
+                size_t n_dns;
+
+                r = network_get_ipv6_dns(link->network, &dns, &n_dns);
+                if (r < 0)
+                        return r;
+
+                needs_uplink = r == 0;
+        }
+
+        if (link->network->router_emit_domains &&
+            !link->network->router_search_domains &&
+            !link->network->search_domains)
+                needs_uplink = true;
+
+        if (needs_uplink) {
+                Link *uplink = NULL;
+
+                if (radv_find_uplink(link, &uplink) < 0)
+                        return false;
+
+                if (uplink && !uplink->network)
+                        return false;
+        }
+
+        return true;
+}
+
+int request_process_radv(Request *req) {
+        Link *link;
+        int r;
+
+        assert(req);
+        assert(req->link);
+        assert(req->type == REQUEST_TYPE_RADV);
+
+        link = req->link;
+
+        r = radv_is_ready_to_configure(link);
+        if (r <= 0)
+                return r;
+
+        r = radv_configure(link);
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to configure IPv6 Router Advertisement engine: %m");
+
+        if (link_has_carrier(link)) {
+                r = sd_radv_start(link->radv);
+                if (r < 0)
+                        return log_link_warning_errno(link, r, "Failed to start IPv6 Router Advertisement engine: %m");
+        }
+
+        log_link_debug(link, "IPv6 Router Advertisement engine is configured%s.",
+                       link_has_carrier(link) ? " and started." : "");
+        return 1;
+}
+
+int link_request_radv(Link *link) {
+        int r;
+
+        assert(link);
+
+        if (!link_radv_enabled(link))
+                return 0;
+
+        if (link->radv)
+                return 0;
+
+        r = link_queue_request(link, REQUEST_TYPE_RADV, NULL, false, NULL, NULL, NULL);
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to request IPv6 Router Advertisement engine: %m");
+
+        log_link_debug(link, "IPv6 Router Advertisement engine is requested.");
+        return 0;
+}
+
 int radv_add_prefix(
                 Link *link,
                 const struct in6_addr *prefix,

src/network/networkd-radv.h

@@ -14,8 +14,9 @@
 #include "conf-parser.h"
 #include "networkd-util.h"
 
-typedef struct Network Network;
 typedef struct Link Link;
+typedef struct Network Network;
+typedef struct Request Request;
 
 typedef enum RADVPrefixDelegation {
         RADV_PREFIX_DELEGATION_NONE   = 0,
@@ -50,12 +51,13 @@ void network_drop_invalid_prefixes(Network *network);
 void network_drop_invalid_route_prefixes(Network *network);
 void network_adjust_radv(Network *network);
 
-int radv_emit_dns(Link *link);
-int radv_configure(Link *link);
 int radv_update_mac(Link *link);
 int radv_add_prefix(Link *link, const struct in6_addr *prefix, uint8_t prefix_len,
                     uint32_t lifetime_preferred, uint32_t lifetime_valid);
 
+int request_process_radv(Request *req);
+int link_request_radv(Link *link);
+
 const char* radv_prefix_delegation_to_string(RADVPrefixDelegation i) _const_;
 RADVPrefixDelegation radv_prefix_delegation_from_string(const char *s) _pure_;
 

test/fuzz/fuzz-network-parser/directives.network

@@ -307,6 +307,7 @@ EmitDNS=
 EmitDomains=
 Managed=
 OtherInformation=
+UplinkInterface=
 [IPv6PrefixDelegation]
 RouterPreference=
 DNSLifetimeSec=

test/test-network/conf/25-vxlan-ipv6.netdev

@@ -0,0 +1,7 @@
+[NetDev]
+Name=vxlan97
+Kind=vxlan
+
+[VXLAN]
+VNI=4831583
+Local=fe80::281:8eff:fef0:73aa

test/test-network/conf/dhcp-server-with-ipv6-prefix.network

@@ -13,3 +13,7 @@ Prefix=2002:da8:1:0::/64
 [DHCPServer]
 DNS=192.168.5.1
 NTP=192.168.5.1
+
+[IPv6SendRA]
+EmitDNS=no
+EmitDomains=no

test/test-network/conf/ipv6ra-prefix-client-deny-list.network

@@ -9,3 +9,4 @@ IPv6AcceptRA=yes
 RouterDenyList=2001::1
 PrefixDenyList=2001:db8:0:2::
 RouteDenyList=2001:db1:fff::
+UseDomains=yes

test/test-network/conf/ipv6ra-prefix-client.network

@@ -11,3 +11,4 @@ PrefixAllowList=2001:db8:0:1:: 2001:db8:0:1::
 PrefixDenyList=2001:db8:0:1:: 2001:db8:0:1::
 RouteAllowList=2001:db0:fff:: 2001:db0:fff::
 RouteDenyList=2001:db0:fff:: 2001:db0:fff::
+UseDomains=yes

test/test-network/conf/ipv6ra-prefix.network

@@ -5,6 +5,9 @@ Name=veth99
 DHCP=no
 IPv6SendRA=yes
 
+[IPv6SendRA]
+UplinkInterface=dummy98
+
 [IPv6Prefix]
 Prefix=2001:db8:0:1::/64
 

test/test-network/conf/ipv6ra-uplink.network

@@ -0,0 +1,8 @@
+[Match]
+Name=dummy98
+
+[Network]
+IPv6AcceptRA=no
+Address=2001:db8:1:1::1/64
+DNS=2001:db8:1:1::2
+Domains=example.com

test/test-network/conf/vxlan-ipv6.network

@@ -0,0 +1,24 @@
+[Match]
+Name=vxlan97
+
+[Network]
+IPv6AcceptRA=no
+LinkLocalAddressing=yes
+
+[BridgeFDB]
+MACAddress=00:00:00:00:00:00
+Destination=fe80::27c:16ff:fec0:6c74
+OutgoingInterface=test1
+VNI=4831583
+
+[BridgeFDB]
+MACAddress=00:00:00:00:00:00
+Destination=fe80::2a2:e4ff:fef9:2269
+OutgoingInterface=test1
+VNI=4831583
+
+[BridgeFDB]
+MACAddress=00:00:00:00:00:00
+Destination=fe80::23b:d2ff:fe95:967f
+OutgoingInterface=test1
+VNI=4831583

test/test-network/conf/vxlan-test1.network

@@ -5,3 +5,4 @@ Name=test1
 IPv6AcceptRA=false
 LinkLocalAddressing=yes
 VXLAN=vxlan99
+VXLAN=vxlan97

test/test-network/systemd-networkd-tests.py

@@ -854,6 +854,7 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
         'vtitun98',
         'vtitun99',
         'vxcan99',
+        'vxlan97',
         'vxlan98',
         'vxlan99',
         'wg97',
@@ -944,6 +945,7 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
         '25-vti-tunnel.netdev',
         '25-vxcan.netdev',
         '25-vxlan-independent.netdev',
+        '25-vxlan-ipv6.netdev',
         '25-vxlan.netdev',
         '25-wireguard-23-peers.netdev',
         '25-wireguard-23-peers.network',
@@ -974,6 +976,7 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
         'sit.network',
         'vti6.network',
         'vti.network',
+        'vxlan-ipv6.network',
         'vxlan-test1.network',
         'vxlan.network',
         'xfrm.network',
@@ -1635,36 +1638,43 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
 
     def test_vxlan(self):
         copy_unit_to_networkd_unit_path('25-vxlan.netdev', 'vxlan.network',
+                                        '25-vxlan-ipv6.netdev', 'vxlan-ipv6.network',
                                         '25-vxlan-independent.netdev', 'netdev-link-local-addressing-yes.network',
                                         '11-dummy.netdev', 'vxlan-test1.network')
         start_networkd()
 
-        self.wait_online(['test1:degraded', 'vxlan99:degraded', 'vxlan98:degraded'])
+        self.wait_online(['test1:degraded', 'vxlan99:degraded', 'vxlan98:degraded', 'vxlan97:degraded'])
 
         output = check_output('ip -d link show vxlan99')
         print(output)
-        self.assertRegex(output, '999')
+        self.assertIn('999', output)
-        self.assertRegex(output, '5555')
+        self.assertIn('5555', output)
-        self.assertRegex(output, 'l2miss')
+        self.assertIn('l2miss', output)
-        self.assertRegex(output, 'l3miss')
+        self.assertIn('l3miss', output)
-        self.assertRegex(output, 'udpcsum')
+        self.assertIn('udpcsum', output)
-        self.assertRegex(output, 'udp6zerocsumtx')
+        self.assertIn('udp6zerocsumtx', output)
-        self.assertRegex(output, 'udp6zerocsumrx')
+        self.assertIn('udp6zerocsumrx', output)
-        self.assertRegex(output, 'remcsumtx')
+        self.assertIn('remcsumtx', output)
-        self.assertRegex(output, 'remcsumrx')
+        self.assertIn('remcsumrx', output)
-        self.assertRegex(output, 'gbp')
+        self.assertIn('gbp', output)
 
         output = check_output('bridge fdb show dev vxlan99')
         print(output)
-        self.assertRegex(output, '00:11:22:33:44:55 dst 10.0.0.5 self permanent')
+        self.assertIn('00:11:22:33:44:55 dst 10.0.0.5 self permanent', output)
-        self.assertRegex(output, '00:11:22:33:44:66 dst 10.0.0.6 self permanent')
+        self.assertIn('00:11:22:33:44:66 dst 10.0.0.6 self permanent', output)
-        self.assertRegex(output, '00:11:22:33:44:77 dst 10.0.0.7 via test1 self permanent')
+        self.assertIn('00:11:22:33:44:77 dst 10.0.0.7 via test1 self permanent', output)
 
         output = check_output(*networkctl_cmd, '-n', '0', 'status', 'vxlan99', env=env)
         print(output)
-        self.assertRegex(output, 'VNI: 999')
+        self.assertIn('VNI: 999', output)
-        self.assertRegex(output, 'Destination Port: 5555')
+        self.assertIn('Destination Port: 5555', output)
-        self.assertRegex(output, 'Underlying Device: test1')
+        self.assertIn('Underlying Device: test1', output)
+
+        output = check_output('bridge fdb show dev vxlan97')
+        print(output)
+        self.assertIn('00:00:00:00:00:00 dst fe80::23b:d2ff:fe95:967f via test1 self permanent', output)
+        self.assertIn('00:00:00:00:00:00 dst fe80::27c:16ff:fec0:6c74 via test1 self permanent', output)
+        self.assertIn('00:00:00:00:00:00 dst fe80::2a2:e4ff:fef9:2269 via test1 self permanent', output)
 
     def test_macsec(self):
         copy_unit_to_networkd_unit_path('25-macsec.netdev', '25-macsec.network', '25-macsec.key',
@@ -4685,14 +4695,19 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
         self.assertRegex(output, 'inet 192.168.5.[0-9]*/24 metric 1024 brd 192.168.5.255 scope global dynamic veth99')
 
 class NetworkdIPv6PrefixTests(unittest.TestCase, Utilities):
-    links = ['veth99']
+    links = [
+        'dummy98',
+        'veth99',
+    ]
 
     units = [
+        '12-dummy.netdev',
         '25-veth.netdev',
         'ipv6ra-prefix-client-deny-list.network',
         'ipv6ra-prefix-client.network',
-        'ipv6ra-prefix.network'
+        'ipv6ra-prefix.network',
-        ]
+        'ipv6ra-uplink.network',
+    ]
 
     def setUp(self):
         remove_links(self.links)
@@ -4705,10 +4720,11 @@ class NetworkdIPv6PrefixTests(unittest.TestCase, Utilities):
         stop_networkd(show_logs=True)
 
     def test_ipv6_route_prefix(self):
-        copy_unit_to_networkd_unit_path('25-veth.netdev', 'ipv6ra-prefix-client.network', 'ipv6ra-prefix.network')
+        copy_unit_to_networkd_unit_path('25-veth.netdev', 'ipv6ra-prefix-client.network', 'ipv6ra-prefix.network',
+                                        '12-dummy.netdev', 'ipv6ra-uplink.network')
 
         start_networkd()
-        self.wait_online(['veth99:routable', 'veth-peer:routable'])
+        self.wait_online(['veth99:routable', 'veth-peer:routable', 'dummy98:routable'])
 
         output = check_output('ip address show dev veth-peer')
         print(output)
@@ -4727,11 +4743,20 @@ class NetworkdIPv6PrefixTests(unittest.TestCase, Utilities):
         self.assertNotIn('inet6 2001:db8:0:1:', output)
         self.assertIn('inet6 2001:db8:0:2:', output)
 
+        output = check_output(*resolvectl_cmd, 'dns', 'veth-peer', env=env)
+        print(output)
+        self.assertRegex(output, '2001:db8:1:1::2')
+
+        output = check_output(*resolvectl_cmd, 'domain', 'veth-peer', env=env)
+        print(output)
+        self.assertIn('example.com', output)
+
     def test_ipv6_route_prefix_deny_list(self):
-        copy_unit_to_networkd_unit_path('25-veth.netdev', 'ipv6ra-prefix-client-deny-list.network', 'ipv6ra-prefix.network')
+        copy_unit_to_networkd_unit_path('25-veth.netdev', 'ipv6ra-prefix-client-deny-list.network', 'ipv6ra-prefix.network',
+                                        '12-dummy.netdev', 'ipv6ra-uplink.network')
 
         start_networkd()
-        self.wait_online(['veth99:routable', 'veth-peer:routable'])
+        self.wait_online(['veth99:routable', 'veth-peer:routable', 'dummy98:routable'])
 
         output = check_output('ip address show dev veth-peer')
         print(output)
@@ -4750,6 +4775,14 @@ class NetworkdIPv6PrefixTests(unittest.TestCase, Utilities):
         self.assertNotIn('inet6 2001:db8:0:1:', output)
         self.assertIn('inet6 2001:db8:0:2:', output)
 
+        output = check_output(*resolvectl_cmd, 'dns', 'veth-peer', env=env)
+        print(output)
+        self.assertRegex(output, '2001:db8:1:1::2')
+
+        output = check_output(*resolvectl_cmd, 'domain', 'veth-peer', env=env)
+        print(output)
+        self.assertIn('example.com', output)
+
 class NetworkdMTUTests(unittest.TestCase, Utilities):
     links = ['dummy98']