network: introduce IPv6 prefix assign

Expose a boolean flag to automatically add an address from the delegated prefix to the interface

man/systemd.network.xml

@@ -2033,6 +2033,11 @@
         to 2592000 seconds (30 days).</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>Assign=</varname></term>
+        <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false.
+        </para></listitem>
+      </varlistentry>
     </variablelist>
     </refsect1>
 

src/network/networkd-link.c

@@ -1222,6 +1222,7 @@ static int link_set_bridge_fdb(Link *link) {
 static int link_request_set_addresses(Link *link) {
         AddressLabel *label;
         Address *ad;
+        Prefix *p;
         int r;
 
         assert(link);
@@ -1257,6 +1258,35 @@ static int link_request_set_addresses(Link *link) {
                         link->address_messages++;
         }
 
+        if (IN_SET(link->network->router_prefix_delegation,
+                   RADV_PREFIX_DELEGATION_STATIC,
+                   RADV_PREFIX_DELEGATION_BOTH))
+                LIST_FOREACH(prefixes, p, link->network->static_prefixes) {
+                        _cleanup_(address_freep) Address *address = NULL;
+
+                        if (!p->assign)
+                                continue;
+
+                        r = address_new(&address);
+                        if (r < 0)
+                                return log_link_error_errno(link, r, "Could not allocate address: %m");
+
+                        r = sd_radv_prefix_get_prefix(p->radv_prefix, &address->in_addr.in6, &address->prefixlen);
+                        if (r < 0)
+                                return r;
+
+                        r = generate_ipv6_eui_64_address(link, &address->in_addr.in6);
+                        if (r < 0)
+                                return r;
+
+                        address->family = AF_INET6;
+                        r = address_configure(address, link, address_handler, true);
+                        if (r < 0)
+                                return log_link_warning_errno(link, r, "Could not set addresses: %m");
+                        if (r > 0)
+                                link->address_messages++;
+                }
+
         LIST_FOREACH(labels, label, link->network->address_labels) {
                 r = address_label_configure(label, link, NULL, false);
                 if (r < 0)

src/network/networkd-network-gperf.gperf

@@ -245,6 +245,7 @@ IPv6Prefix.OnLink,                           config_parse_prefix_flags,
 IPv6Prefix.AddressAutoconfiguration,         config_parse_prefix_flags,                                0,                             0
 IPv6Prefix.ValidLifetimeSec,                 config_parse_prefix_lifetime,                             0,                             0
 IPv6Prefix.PreferredLifetimeSec,             config_parse_prefix_lifetime,                             0,                             0
+IPv6Prefix.Assign,                           config_parse_prefix_assign,                               0,                             0
 IPv6RoutePrefix.Route,                       config_parse_route_prefix,                                0,                             0
 IPv6RoutePrefix.LifetimeSec,                 config_parse_route_prefix_lifetime,                       0,                             0
 CAN.BitRate,                                 config_parse_si_uint64,                                   0,                             offsetof(Network, can_bitrate)

src/network/networkd-radv.c

@@ -319,6 +319,46 @@ int config_parse_prefix_lifetime(const char *unit,
         return 0;
 }
 
+int config_parse_prefix_assign(
+                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;
+        _cleanup_(prefix_free_or_set_invalidp) Prefix *p = NULL;
+        int r;
+
+        assert(filename);
+        assert(section);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        r = prefix_new_static(network, filename, section_line, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_boolean(rvalue);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r,
+                           "Failed to parse %s=, ignoring assignment: %s",
+                           lvalue, rvalue);
+                return 0;
+        }
+
+        p->assign = r;
+        p = NULL;
+
+        return 0;
+}
+
 int config_parse_route_prefix(const char *unit,
                               const char *filename,
                               unsigned line,

src/network/networkd-radv.h

@@ -28,6 +28,8 @@ struct Prefix {
 
         sd_radv_prefix *radv_prefix;
 
+        bool assign;
+
         LIST_FIELDS(Prefix, prefixes);
 };
 
@@ -59,6 +61,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_router_preference);
 CONFIG_PARSER_PROTOTYPE(config_parse_prefix);
 CONFIG_PARSER_PROTOTYPE(config_parse_prefix_flags);
 CONFIG_PARSER_PROTOTYPE(config_parse_prefix_lifetime);
+CONFIG_PARSER_PROTOTYPE(config_parse_prefix_assign);
 CONFIG_PARSER_PROTOTYPE(config_parse_radv_dns);
 CONFIG_PARSER_PROTOTYPE(config_parse_radv_search_domains);
 CONFIG_PARSER_PROTOTYPE(config_parse_route_prefix);

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

@@ -186,6 +186,7 @@ OnLink=
 PreferredLifetimeSec=
 AddressAutoconfiguration=
 ValidLifetimeSec=
+Assign=
 [IPv6RoutePrefix]
 Route=
 LifetimeSec=