networkd: generalize IPv4LL to LinkLocal

This allows both IPv4 and IPv6 link-local addresses to be enabled or disabled. By default
we still enable IPv6LL and disable IPv4LL. The old config option is kept for backwards
compatibility, but removed from the documentation.

9 files changed, 96 insertions, 11 deletions

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index b8facdc0af..6c137e16e9 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -236,10 +236,12 @@
           </listitem>
         </varlistentry>
         <varlistentry>
-          <term><varname>IPv4LL=</varname></term>
+          <term><varname>LinkLocal=</varname></term>
           <listitem>
-            <para>A boolean. When true, enables IPv4 link-local support.
-            </para>
+            <para>Enables link-local address autoconfiguration. Accepts
+            <literal>yes</literal>, <literal>no</literal>,
+            <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults to
+            <literal>ipv6</literal>.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
diff --git a/network/80-container-host0.network b/network/80-container-host0.network
index 8d9293f239..4e68c3d549 100644
--- a/network/80-container-host0.network
+++ b/network/80-container-host0.network
@@ -11,4 +11,4 @@ Name=host0
 
 [Network]
 DHCP=yes
-IPv4LL=yes
+LinkLocal=yes
diff --git a/network/80-container-ve.network b/network/80-container-ve.network
index 7bde1d4934..cac436d81d 100644
--- a/network/80-container-ve.network
+++ b/network/80-container-ve.network
@@ -12,6 +12,6 @@ Driver=veth
 [Network]
 # Default to using a /28 prefix, giving up to 13 addresses per container.
 Address=0.0.0.0/28
-IPv4LL=yes
+LinkLocal=yes
 DHCPServer=yes
 IPMasquerade=yes
diff --git a/src/network/networkd-ipv4ll.c b/src/network/networkd-ipv4ll.c
index 339bf4d190..8050801e19 100644
--- a/src/network/networkd-ipv4ll.c
+++ b/src/network/networkd-ipv4ll.c
@@ -209,7 +209,7 @@ int ipv4ll_configure(Link *link) {
 
         assert(link);
         assert(link->network);
-        assert(link->network->ipv4ll);
+        assert(IN_SET(link->network->link_local, ADDRESS_FAMILY_IPV4, ADDRESS_FAMILY_YES));
 
         r = sd_ipv4ll_new(&link->ipv4ll);
         if (r < 0)
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index eff1ce94be..3b9881d71e 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -72,7 +72,17 @@ bool link_ipv4ll_enabled(Link *link) {
         if (!link->network)
                 return false;
 
-        return link->network->ipv4ll;
+        return IN_SET(link->network->link_local, ADDRESS_FAMILY_IPV4, ADDRESS_FAMILY_YES);
+}
+
+bool link_ipv6ll_enabled(Link *link) {
+        if (link->flags & IFF_LOOPBACK)
+                return false;
+
+        if (!link->network)
+                return false;
+
+        return IN_SET(link->network->link_local, ADDRESS_FAMILY_IPV6, ADDRESS_FAMILY_YES);
 }
 
 bool link_lldp_enabled(Link *link) {
@@ -1087,6 +1097,38 @@ static int link_up(Link *link) {
                 }
         }
 
+        if (!link_ipv6ll_enabled(link)) {
+                r = sd_rtnl_message_open_container(req, IFLA_AF_SPEC);
+                if (r < 0) {
+                        log_link_error(link, "Could not open IFLA_AF_SPEC container: %s", strerror(-r));
+                        return r;
+                }
+
+                r = sd_rtnl_message_open_container(req, AF_INET6);
+                if (r < 0) {
+                        log_link_error(link, "Could not open AF_INET6 container: %s", strerror(-r));
+                        return r;
+                }
+
+                r = sd_rtnl_message_append_u8(req, IFLA_INET6_ADDR_GEN_MODE, IN6_ADDR_GEN_MODE_NONE);
+                if (r < 0) {
+                        log_link_error(link, "Could not append IFLA_INET6_ADDR_GEN_MODE: %s", strerror(-r));
+                        return r;
+                }
+
+                r = sd_rtnl_message_close_container(req);
+                if (r < 0) {
+                        log_link_error(link, "Could not close AF_INET6 contaire: %s", strerror(-r));
+                        return r;
+                }
+
+                r = sd_rtnl_message_close_container(req);
+                if (r < 0) {
+                        log_link_error(link, "Could not close IFLA_AF_SPEC contaire: %s", strerror(-r));
+                        return r;
+                }
+        }
+
         r = sd_rtnl_call_async(link->manager->rtnl, req, link_up_handler, link,
                                0, NULL);
         if (r < 0) {
@@ -1391,8 +1433,8 @@ static int link_initialized_and_synced(sd_rtnl *rtnl, sd_rtnl_message *m,
                 return r;
 
         if (link->flags & IFF_LOOPBACK) {
-                if (network->ipv4ll)
-                        log_link_debug(link, "ignoring IPv4LL for loopback link");
+                if (network->link_local != ADDRESS_FAMILY_NO)
+                        log_link_debug(link, "ignoring link-local autoconfiguration for loopback link");
 
                 if (network->dhcp != ADDRESS_FAMILY_NO)
                         log_link_debug(link, "ignoring DHCP clients for loopback link");
diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index ce83f24da3..449dbc8846 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -116,6 +116,7 @@ int icmp6_configure(Link *link);
 
 bool link_lldp_enabled(Link *link);
 bool link_ipv4ll_enabled(Link *link);
+bool link_ipv6ll_enabled(Link *link);
 bool link_dhcp4_server_enabled(Link *link);
 bool link_dhcp4_enabled(Link *link);
 bool link_dhcp6_enabled(Link *link);
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 26fce97b6a..525f2ba799 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -36,7 +36,7 @@ Network.VXLAN,               config_parse_netdev,                0,
 Network.Tunnel,              config_parse_tunnel,                0,                             0
 Network.DHCP,                config_parse_dhcp,                  0,                             offsetof(Network, dhcp)
 Network.DHCPServer,          config_parse_bool,                  0,                             offsetof(Network, dhcp_server)
-Network.IPv4LL,              config_parse_bool,                  0,                             offsetof(Network, ipv4ll)
+Network.LinkLocal,           config_parse_address_family_boolean,0,                             offsetof(Network, link_local)
 Network.IPv4LLRoute,         config_parse_bool,                  0,                             offsetof(Network, ipv4ll_route)
 Network.LLDP,                config_parse_bool,                  0,                             offsetof(Network, lldp)
 Network.Address,             config_parse_address,               0,                             0
@@ -69,6 +69,7 @@ Bridge.Cost,                 config_parse_unsigned,              0,
 BridgeFDB.MACAddress,        config_parse_fdb_hwaddr,            0,                             0
 BridgeFDB.VLANId,            config_parse_fdb_vlan_id,           0,                             0
 /* backwards compatibility: do not add new entries to this section */
+Network.IPv4LL,              config_parse_ipv4ll,                0,                             offsetof(Network, link_local)
 DHCPv4.UseDNS,               config_parse_bool,                  0,                             offsetof(Network, dhcp_dns)
 DHCPv4.UseMTU,               config_parse_bool,                  0,                             offsetof(Network, dhcp_mtu)
 DHCPv4.UseHostname,          config_parse_bool,                  0,                             offsetof(Network, dhcp_hostname)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 504419cdb0..c39ba6dfa2 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -107,6 +107,8 @@ static int network_load_one(Manager *manager, const char *filename) {
 
         network->llmnr = LLMNR_SUPPORT_YES;
 
+        network->link_local = ADDRESS_FAMILY_IPV6;
+
         r = config_parse(NULL, filename, file,
                          "Match\0"
                          "Link\0"
@@ -520,6 +522,37 @@ int config_parse_tunnel(const char *unit,
         return 0;
 }
 
+int config_parse_ipv4ll(
+                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) {
+
+        AddressFamilyBoolean *link_local = data;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        /* Note that this is mostly like
+         * config_parse_address_family_boolean(), except that it
+         * applies only to IPv4 */
+
+        if (parse_boolean(rvalue))
+                *link_local |= ADDRESS_FAMILY_IPV4;
+        else
+                *link_local &= ~ADDRESS_FAMILY_IPV4;
+
+        return 0;
+}
+
 int config_parse_dhcp(
                 const char* unit,
                 const char *filename,
diff --git a/src/network/networkd.h b/src/network/networkd.h
index 147b21acdc..4f3bcf36f9 100644
--- a/src/network/networkd.h
+++ b/src/network/networkd.h
@@ -126,7 +126,7 @@ struct Network {
         bool dhcp_critical;
         bool dhcp_routes;
         unsigned dhcp_route_metric;
-        bool ipv4ll;
+        AddressFamilyBoolean link_local;
         bool ipv4ll_route;
 
         bool dhcp_server;
@@ -399,6 +399,12 @@ int config_parse_dhcp(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);
 
+/* IPv4LL support (legacy) */
+
+int config_parse_ipv4ll(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);
+
 /* LLMNR support */
 
 const char* llmnr_support_to_string(LLMNRSupport i) _const_;