Merge pull request #3156 from keszybz/duid-settings

Rework DUID setting

46 files changed, 671 insertions, 435 deletions

diff --git a/.gitignore b/.gitignore
index c7eb14452d..c17f79224b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -235,6 +235,7 @@
 /test-ndisc-rs
 /test-netlink
 /test-netlink-manual
+/test-netword-conf
 /test-network
 /test-network-tables
 /test-ns
diff --git a/Makefile.am b/Makefile.am
index a05c7ce4db..cf4e75996d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5515,6 +5515,12 @@ networkctl_LDADD = \
 dist_bashcompletion_data += \
 	shell-completion/bash/networkctl
 
+test_networkd_conf_SOURCES = \
+	src/network/test-networkd-conf.c
+
+test_networkd_conf_LDADD = \
+	libnetworkd-core.la
+
 test_network_SOURCES = \
 	src/network/test-network.c
 
@@ -5540,6 +5546,7 @@ test_network_tables_LDADD += \
 endif
 
 tests += \
+	test-networkd-conf \
 	test-network \
 	test-network-tables
 
diff --git a/man/networkd.conf.xml b/man/networkd.conf.xml
index 5166e05cbc..4bfc4f773a 100644
--- a/man/networkd.conf.xml
+++ b/man/networkd.conf.xml
@@ -58,14 +58,14 @@
     <title>Description</title>
 
     <para>These configuration files control global network parameters.
-    For e.g. DHCP Unique Identifier (DUID).</para>
+    Currently the DHCP Unique Identifier (DUID).</para>
 
   </refsect1>
 
   <xi:include href="standard-conf.xml" xpointer="main-conf" />
 
   <refsect1>
-    <title>[DUID] Section Options</title>
+    <title>[DHCP] Section Options</title>
 
     <para>This section configures the DHCP Unique Identifier (DUID) value used by DHCP
     protocol. DHCPv6 client protocol sends the DHCP Unique Identifier and the interface
@@ -73,28 +73,71 @@
     address. DHCPv4 client protocol sends IAID and DUID to the DHCP server when acquiring
     a dynamic IPv4 address if <option>ClientIdentifier=duid</option>. IAID and DUID allows
     a DHCP server to uniquely identify the machine and the interface requesting a DHCP IP.
-    To configure IAID and ClientIdentifier, see <citerefentry><refentrytitle>systemd.network
-    </refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+    To configure IAID and ClientIdentifier, see
+    <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+    </para>
 
-    <para>The DUID value specified here overrides the DUID that systemd-networkd
-    generates using the machine-id from the <filename>/etc/machine-id</filename> file.
-    To configure DUID per-network, see <citerefentry><refentrytitle>systemd.network
-    </refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
-
-    <para>The configured DHCP DUID should conform to the specification in 
-    <ulink url="http://tools.ietf.org/html/rfc3315#section-9">RFC 3315</ulink>,
-    <ulink url="http://tools.ietf.org/html/rfc6355">RFC 6355</ulink>. To configure IAID, see
-    <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
-    </citerefentry>.</para>
-
-    <para>The following options are available in <literal>[DUID]</literal> section:</para>
+    <para>The following options are understood:</para>
 
     <variablelist class='network-directives'>
+      <varlistentry>
+        <term><varname>DUIDType=</varname></term>
+        <listitem><para>Specifies how the DUID should be generated. See
+        <ulink url="https://tools.ietf.org/html/rfc3315#section-9">RFC 3315</ulink>
+        for a description of all the options.</para>
+
+        <para>The following values are understood:
+        <variablelist>
+          <varlistentry>
+            <term><option>vendor</option> </term>
+            <listitem><para>If <literal>DUIDType=vendor</literal>, then the DUID value will be generated using
+            <literal>43793</literal> as the vendor identifier (systemd) and hashed contents of
+            <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+            This is the default if <varname>DUIDType=</varname> is not specified.
+            </para></listitem>
+          </varlistentry>
+
+          <varlistentry>
+            <term><option>link-layer-time</option> </term>
+            <term><option>link-layer</option> </term>
+            <term><option>uuid</option> </term>
+            <listitem><para>Those values are parsed and can be used to set the DUID type
+            field, but DUID contents must be provided using <varname>DUIDRawData=</varname>.
+            </para></listitem>
+          </varlistentry>
+        </variablelist>
+        </para>
+
+        <para>In all cases, <varname>DUIDRawData=</varname> can be used to override the
+        actual DUID value that is used.</para></listitem>
+      </varlistentry>
 
       <varlistentry>
-        <term><varname>RawData=</varname></term>
-        <listitem><para>Specifies the DUID bytes as a single newline-terminated, hexadecimal
-        string, with each byte separated by a ':'.</para></listitem>
+        <term><varname>DUIDRawData=</varname></term>
+        <listitem><para>Specifies the DHCP DUID value as a single newline-terminated, hexadecimal string, with each
+        byte separated by <literal>:</literal>. The DUID that is sent is composed of the DUID type specified by
+        <varname>DUIDType=</varname> and the value configured here.</para>
+
+        <para>The DUID value specified here overrides the DUID that systemd-networkd generates using the machine-id
+        from the <filename>/etc/machine-id</filename> file. To configure DUID per-network, see
+        <citerefentry><refentrytitle>systemd.network </refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+        The configured DHCP DUID should conform to the specification in
+        <ulink url="http://tools.ietf.org/html/rfc3315#section-9">RFC 3315</ulink>,
+        <ulink url="http://tools.ietf.org/html/rfc6355">RFC 6355</ulink>. To configure IAID, see
+        <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
+        </citerefentry>.</para>
+
+        <example>
+          <title>A <option>DUIDType=vendor</option> with a custom value</title>
+
+          <programlisting>DUIDType=vendor
+DUIDRawData=00:00:ab:11:f9:2a:c2:77:29:f9:5c:00</programlisting>
+
+          <para>This specifies a 14 byte DUID, with the type DUID-EN (<literal>00:02</literal>), enterprise number
+          43793 (<literal>00:00:ab:11</literal>), and identifier value <literal>f9:2a:c2:77:29:f9:5c:00</literal>.
+          </para>
+        </example>
+        </listitem>
       </varlistentry>
     </variablelist>
   </refsect1>
diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 5e287faa6e..3ee80a64a0 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -832,6 +832,7 @@
             false.</para>
           </listitem>
         </varlistentry>
+
         <varlistentry>
           <term><varname>ClientIdentifier=</varname></term>
           <listitem>
@@ -839,6 +840,7 @@
             or <literal>duid</literal> (the default, see below) to use a RFC4361-compliant Client ID.</para>
           </listitem>
         </varlistentry>
+
         <varlistentry>
           <term><varname>VendorClassIdentifier=</varname></term>
           <listitem>
@@ -846,25 +848,25 @@
             type and configuration.</para>
           </listitem>
         </varlistentry>
-        <varlistentry>
-          <term><varname>DUIDRawData=</varname></term>
-          <listitem><para>Specifies the DHCP DUID bytes as a single newline-terminated, hexadecimal string, with each
-          byte separated by a ':'.  A DHCPv6 client sends the DHCP Unique Identifier (DUID) and the interface Identity
-          Association Identifier (IAID) to a DHCP server when acquiring a dynamic IPv6 address. Similar, DHCPv4 clients
-          send the IAID and DUID to the DHCP server when acquiring a dynamic IPv4 address if
-          <option>ClientIdentifier=duid</option>. IAID and DUID allows a DHCP server to uniquely identify the machine
-          and the interface requesting a DHCP IP address.</para>
 
-          <para>The DUID value specified here takes precedence over the DUID that systemd-networkd generates
-          using the machine-id from the <filename>/etc/machine-id</filename> file, as well as the
-          global DUID that may be specified in <citerefentry><refentrytitle>networkd.conf
-          </refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+        <varlistentry>
+          <term><varname>DUIDType=</varname></term>
+          <listitem>
+            <para>Override the global <varname>DUIDType</varname> setting for this network. See
+            <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+            for a description of possible values.</para>
+          </listitem>
+        </varlistentry>
 
-          <para>The configured DHCP DUID should conform to the specification in
-          <ulink url="http://tools.ietf.org/html/rfc3315#section-9">RFC 3315</ulink>,
-          <ulink url="http://tools.ietf.org/html/rfc6355">RFC 6355</ulink>.</para>
+        <varlistentry>
+          <term><varname>DUIDRawData=</varname></term>
+          <listitem>
+            <para>Override the global <varname>DUIDRawData</varname> setting for this network. See
+            <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+            for a description of possible values.</para>
           </listitem>
         </varlistentry>
+
         <varlistentry>
           <term><varname>RequestBroadcast=</varname></term>
           <listitem>
@@ -876,6 +878,7 @@
             networks where broadcasts are filtered out.</para>
           </listitem>
         </varlistentry>
+
         <varlistentry>
           <term><varname>RouteMetric=</varname></term>
           <listitem>
diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
index 4f7d4d8bf2..a21efc4d06 100644
--- a/src/libsystemd-network/dhcp-identifier.c
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -31,6 +31,37 @@
 #define SYSTEMD_PEN 43793
 #define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
 
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len) {
+        struct duid d;
+
+        assert_cc(sizeof(d.raw) >= MAX_DUID_LEN);
+        if (duid_len > MAX_DUID_LEN)
+                return -EINVAL;
+
+        switch (duid_type) {
+        case DUID_TYPE_LLT:
+                if (duid_len <= sizeof(d.llt))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_EN:
+                if (duid_len != sizeof(d.en))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_LL:
+                if (duid_len <= sizeof(d.ll))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_UUID:
+                if (duid_len != sizeof(d.uuid))
+                        return -EINVAL;
+                break;
+        default:
+                /* accept unknown type in order to be forward compatible */
+                break;
+        }
+        return 0;
+}
+
 int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) {
         sd_id128_t machine_id;
         uint64_t hash;
diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
index e6486b78f8..1cc0f9fb71 100644
--- a/src/libsystemd-network/dhcp-identifier.h
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -26,7 +26,6 @@
 #include "unaligned.h"
 
 typedef enum DUIDType {
-        DUID_TYPE_RAW       = 0,
         DUID_TYPE_LLT       = 1,
         DUID_TYPE_EN        = 2,
         DUID_TYPE_LL        = 3,
@@ -40,27 +39,28 @@ typedef enum DUIDType {
  */
 #define MAX_DUID_LEN 128
 
+/* https://tools.ietf.org/html/rfc3315#section-9.1 */
 struct duid {
         be16_t type;
         union {
                 struct {
-                        /* DHCP6_DUID_LLT */
+                        /* DUID_TYPE_LLT */
                         uint16_t htype;
                         uint32_t time;
                         uint8_t haddr[0];
                 } _packed_ llt;
                 struct {
-                        /* DHCP6_DUID_EN */
+                        /* DUID_TYPE_EN */
                         uint32_t pen;
                         uint8_t id[8];
                 } _packed_ en;
                 struct {
-                        /* DHCP6_DUID_LL */
+                        /* DUID_TYPE_LL */
                         int16_t htype;
                         uint8_t haddr[0];
                 } _packed_ ll;
                 struct {
-                        /* DHCP6_DUID_UUID */
+                        /* DUID_TYPE_UUID */
                         sd_id128_t uuid;
                 } _packed_ uuid;
                 struct {
@@ -69,36 +69,6 @@ struct duid {
         };
 } _packed_;
 
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len);
 int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len);
 int dhcp_identifier_set_iaid(int ifindex, uint8_t *mac, size_t mac_len, void *_id);
-
-static inline int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len) {
-        struct duid d;
-
-        assert(duid_len > 0);
-
-        switch (duid_type) {
-        case DUID_TYPE_LLT:
-                if (duid_len <= sizeof(d.llt))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_EN:
-                if (duid_len != sizeof(d.en))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_LL:
-                if (duid_len <= sizeof(d.ll))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_UUID:
-                if (duid_len != sizeof(d.uuid))
-                        return -EINVAL;
-                break;
-        default:
-                if (duid_len > sizeof(d.raw))
-                        return -EINVAL;
-                /* accept unknown type in order to be forward compatible */
-                break;
-        }
-        return 0;
-}
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 287b6e26fa..3846cf7476 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -115,14 +115,22 @@ static const uint8_t default_req_opts[] = {
         SD_DHCP_OPTION_DOMAIN_NAME_SERVER,
 };
 
-static int client_receive_message_raw(sd_event_source *s, int fd,
-                                      uint32_t revents, void *userdata);
-static int client_receive_message_udp(sd_event_source *s, int fd,
-                                      uint32_t revents, void *userdata);
+static int client_receive_message_raw(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata);
+static int client_receive_message_udp(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata);
 static void client_stop(sd_dhcp_client *client, int error);
 
-int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_callback_t cb,
-                                void *userdata) {
+int sd_dhcp_client_set_callback(
+                sd_dhcp_client *client,
+                sd_dhcp_client_callback_t cb,
+                void *userdata) {
         assert_return(client, -EINVAL);
 
         client->cb = cb;
@@ -171,8 +179,9 @@ int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
         return 0;
 }
 
-int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
-                                       const struct in_addr *last_addr) {
+int sd_dhcp_client_set_request_address(
+                sd_dhcp_client *client,
+                const struct in_addr *last_addr) {
         assert_return(client, -EINVAL);
         assert_return (IN_SET(client->state, DHCP_STATE_INIT,
                               DHCP_STATE_STOPPED), -EBUSY);
@@ -196,8 +205,12 @@ int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
         return 0;
 }
 
-int sd_dhcp_client_set_mac(sd_dhcp_client *client, const uint8_t *addr,
-                           size_t addr_len, uint16_t arp_type) {
+int sd_dhcp_client_set_mac(
+                sd_dhcp_client *client,
+                const uint8_t *addr,
+                size_t addr_len,
+                uint16_t arp_type) {
+
         DHCP_CLIENT_DONT_DESTROY(client);
         bool need_restart = false;
 
@@ -234,8 +247,11 @@ int sd_dhcp_client_set_mac(sd_dhcp_client *client, const uint8_t *addr,
         return 0;
 }
 
-int sd_dhcp_client_get_client_id(sd_dhcp_client *client, uint8_t *type,
-                                 const uint8_t **data, size_t *data_len) {
+int sd_dhcp_client_get_client_id(
+                sd_dhcp_client *client,
+                uint8_t *type,
+                const uint8_t **data,
+                size_t *data_len) {
 
         assert_return(client, -EINVAL);
         assert_return(type, -EINVAL);
@@ -254,8 +270,12 @@ int sd_dhcp_client_get_client_id(sd_dhcp_client *client, uint8_t *type,
         return 0;
 }
 
-int sd_dhcp_client_set_client_id(sd_dhcp_client *client, uint8_t type,
-                                 const uint8_t *data, size_t data_len) {
+int sd_dhcp_client_set_client_id(
+                sd_dhcp_client *client,
+                uint8_t type,
+                const uint8_t *data,
+                size_t data_len) {
+
         DHCP_CLIENT_DONT_DESTROY(client);
         bool need_restart = false;
 
@@ -298,13 +318,32 @@ int sd_dhcp_client_set_client_id(sd_dhcp_client *client, uint8_t type,
         return 0;
 }
 
-int sd_dhcp_client_set_iaid_duid(sd_dhcp_client *client, uint32_t iaid,
-                                 uint16_t duid_type, uint8_t *duid, size_t duid_len) {
+/**
+ * Sets IAID and DUID. If duid is non-null, the DUID is set to duid_type + duid
+ * without further modification. Otherwise, if duid_type is supported, DUID
+ * is set based on that type. Otherwise, an error is returned.
+ */
+int sd_dhcp_client_set_iaid_duid(
+                sd_dhcp_client *client,
+                uint32_t iaid,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len) {
+
         DHCP_CLIENT_DONT_DESTROY(client);
         int r;
+        size_t len;
+
         assert_return(client, -EINVAL);
-        zero(client->client_id);
+        assert_return(duid_len == 0 || duid != NULL, -EINVAL);
+
+        if (duid != NULL) {
+                r = dhcp_validate_duid_len(duid_type, duid_len);
+                if (r < 0)
+                        return r;
+        }
 
+        zero(client->client_id);
         client->client_id.type = 255;
 
         /* If IAID is not configured, generate it. */
@@ -317,22 +356,18 @@ int sd_dhcp_client_set_iaid_duid(sd_dhcp_client *client, uint32_t iaid,
         } else
                 client->client_id.ns.iaid = htobe32(iaid);
 
-        /* If DUID is not configured, generate DUID-EN. */
-        if (duid_len == 0) {
-                r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid,
-                                                &duid_len);
-                if (r < 0)
-                        return r;
-        } else {
-                r = dhcp_validate_duid_len(client->client_id.type, duid_len);
-                if (r < 0)
-                        return r;
+        if (duid != NULL) {
                 client->client_id.ns.duid.type = htobe16(duid_type);
                 memcpy(&client->client_id.ns.duid.raw.data, duid, duid_len);
-                duid_len += sizeof(client->client_id.ns.duid.type);
-        }
+                len = sizeof(client->client_id.ns.duid.type) + duid_len;
+        } else if (duid_type == DUID_TYPE_EN) {
+                r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &len);
+                if (r < 0)
+                        return r;
+        } else
+                return -EOPNOTSUPP;
 
-        client->client_id_len = sizeof(client->client_id.type) + duid_len +
+        client->client_id_len = sizeof(client->client_id.type) + len +
                                 sizeof(client->client_id.ns.iaid);
 
         if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) {
@@ -344,8 +379,10 @@ int sd_dhcp_client_set_iaid_duid(sd_dhcp_client *client, uint32_t iaid,
         return 0;
 }
 
-int sd_dhcp_client_set_hostname(sd_dhcp_client *client,
-                                const char *hostname) {
+int sd_dhcp_client_set_hostname(
+                sd_dhcp_client *client,
+                const char *hostname) {
+
         char *new_hostname = NULL;
 
         assert_return(client, -EINVAL);
@@ -368,8 +405,10 @@ int sd_dhcp_client_set_hostname(sd_dhcp_client *client,
         return 0;
 }
 
-int sd_dhcp_client_set_vendor_class_identifier(sd_dhcp_client *client,
-                                               const char *vci) {
+int sd_dhcp_client_set_vendor_class_identifier(
+                sd_dhcp_client *client,
+                const char *vci) {
+
         char *new_vci = NULL;
 
         assert_return(client, -EINVAL);
@@ -452,8 +491,13 @@ static void client_stop(sd_dhcp_client *client, int error) {
         client_initialize(client);
 }
 
-static int client_message_init(sd_dhcp_client *client, DHCPPacket **ret,
-                               uint8_t type, size_t *_optlen, size_t *_optoffset) {
+static int client_message_init(
+                sd_dhcp_client *client,
+                DHCPPacket **ret,
+                uint8_t type,
+                size_t *_optlen,
+                size_t *_optoffset) {
+
         _cleanup_free_ DHCPPacket *packet = NULL;
         size_t optlen, optoffset, size;
         be16_t max_size;
@@ -594,8 +638,12 @@ static int client_message_init(sd_dhcp_client *client, DHCPPacket **ret,
         return 0;
 }
 
-static int client_append_fqdn_option(DHCPMessage *message, size_t optlen, size_t *optoffset,
-                                     const char *fqdn) {
+static int client_append_fqdn_option(
+                DHCPMessage *message,
+                size_t optlen,
+                size_t *optoffset,
+                const char *fqdn) {
+
         uint8_t buffer[3 + DHCP_MAX_FQDN_LENGTH];
         int r;
 
@@ -612,8 +660,11 @@ static int client_append_fqdn_option(DHCPMessage *message, size_t optlen, size_t
         return r;
 }
 
-static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
-                                size_t len) {
+static int dhcp_client_send_raw(
+                sd_dhcp_client *client,
+                DHCPPacket *packet,
+                size_t len) {
+
         dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
                                       INADDR_BROADCAST, DHCP_PORT_SERVER, len);
 
@@ -820,8 +871,11 @@ static int client_send_request(sd_dhcp_client *client) {
 
 static int client_start(sd_dhcp_client *client);
 
-static int client_timeout_resend(sd_event_source *s, uint64_t usec,
-                                 void *userdata) {
+static int client_timeout_resend(
+                sd_event_source *s,
+                uint64_t usec,
+                void *userdata) {
+
         sd_dhcp_client *client = userdata;
         DHCP_CLIENT_DONT_DESTROY(client);
         usec_t next_timeout = 0;
@@ -965,8 +1019,10 @@ error:
         return 0;
 }
 
-static int client_initialize_io_events(sd_dhcp_client *client,
-                                       sd_event_io_handler_t io_callback) {
+static int client_initialize_io_events(
+                sd_dhcp_client *client,
+                sd_event_io_handler_t io_callback) {
+
         int r;
 
         assert(client);
@@ -1033,8 +1089,7 @@ error:
 
 }
 
-static int client_initialize_events(sd_dhcp_client *client,
-                                    sd_event_io_handler_t io_callback) {
+static int client_initialize_events(sd_dhcp_client *client, sd_event_io_handler_t io_callback) {
         client_initialize_io_events(client, io_callback);
         client_initialize_time_events(client);
 
@@ -1074,8 +1129,7 @@ static int client_start(sd_dhcp_client *client) {
         return client_start_delayed(client);
 }
 
-static int client_timeout_expire(sd_event_source *s, uint64_t usec,
-                                 void *userdata) {
+static int client_timeout_expire(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp_client *client = userdata;
         DHCP_CLIENT_DONT_DESTROY(client);
 
@@ -1115,8 +1169,7 @@ static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
         return client_initialize_events(client, client_receive_message_raw);
 }
 
-static int client_timeout_t1(sd_event_source *s, uint64_t usec,
-                             void *userdata) {
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp_client *client = userdata;
         DHCP_CLIENT_DONT_DESTROY(client);
 
@@ -1126,8 +1179,7 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec,
         return client_initialize_time_events(client);
 }
 
-static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
-                               size_t len) {
+static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, size_t len) {
         _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;
         int r;
 
@@ -1178,8 +1230,7 @@ static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
         return 0;
 }
 
-static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force,
-                                    size_t len) {
+static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force, size_t len) {
         int r;
 
         r = dhcp_option_parse(force, len, NULL, NULL, NULL);
@@ -1191,8 +1242,7 @@ static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force,
         return 0;
 }
 
-static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
-                             size_t len) {
+static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, size_t len) {
         _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;
         _cleanup_free_ char *error_message = NULL;
         int r;
@@ -1420,8 +1470,7 @@ static int client_set_lease_timeouts(sd_dhcp_client *client) {
         return 0;
 }
 
-static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
-                                 int len) {
+static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, int len) {
         DHCP_CLIENT_DONT_DESTROY(client);
         char time_string[FORMAT_TIMESPAN_MAX];
         int r = 0, notify_event = 0;
@@ -1567,8 +1616,12 @@ error:
         return r;
 }
 
-static int client_receive_message_udp(sd_event_source *s, int fd,
-                                      uint32_t revents, void *userdata) {
+static int client_receive_message_udp(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
         sd_dhcp_client *client = userdata;
         _cleanup_free_ DHCPMessage *message = NULL;
         const struct ether_addr zero_mac = { { 0, 0, 0, 0, 0, 0 } };
@@ -1645,8 +1698,12 @@ static int client_receive_message_udp(sd_event_source *s, int fd,
         return client_handle_message(client, message, len);
 }
 
-static int client_receive_message_raw(sd_event_source *s, int fd,
-                                      uint32_t revents, void *userdata) {
+static int client_receive_message_raw(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
         sd_dhcp_client *client = userdata;
         _cleanup_free_ DHCPPacket *packet = NULL;
         uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index ee4fb4fc1e..4adb053a57 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -111,7 +111,10 @@ DEFINE_STRING_TABLE_LOOKUP(dhcp6_message_status, int);
 
 static int client_start(sd_dhcp6_client *client, enum DHCP6State state);
 
-int sd_dhcp6_client_set_callback(sd_dhcp6_client *client, sd_dhcp6_client_callback_t cb, void *userdata) {
+int sd_dhcp6_client_set_callback(
+                sd_dhcp6_client *client,
+                sd_dhcp6_client_callback_t cb,
+                void *userdata) {
         assert_return(client, -EINVAL);
 
         client->cb = cb;
@@ -131,7 +134,10 @@ int sd_dhcp6_client_set_index(sd_dhcp6_client *client, int interface_index) {
         return 0;
 }
 
-int sd_dhcp6_client_set_local_address(sd_dhcp6_client *client, const struct in6_addr *local_address) {
+int sd_dhcp6_client_set_local_address(
+                sd_dhcp6_client *client,
+                const struct in6_addr *local_address) {
+
         assert_return(client, -EINVAL);
         assert_return(local_address, -EINVAL);
         assert_return(in_addr_is_link_local(AF_INET6, (const union in_addr_union *) local_address) > 0, -EINVAL);
@@ -180,20 +186,38 @@ static int client_ensure_duid(sd_dhcp6_client *client) {
         return dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
 }
 
-int sd_dhcp6_client_set_duid(sd_dhcp6_client *client, uint16_t duid_type,
-                             uint8_t *duid, size_t duid_len) {
+/**
+ * Sets DUID. If duid is non-null, the DUID is set to duid_type + duid
+ * without further modification. Otherwise, if duid_type is supported, DUID
+ * is set based on that type. Otherwise, an error is returned.
+ */
+int sd_dhcp6_client_set_duid(
+                sd_dhcp6_client *client,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len) {
+
         int r;
         assert_return(client, -EINVAL);
+        assert_return(duid_len == 0 || duid != NULL, -EINVAL);
         assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
 
-        if (duid_len > 0) {
+        if (duid != NULL) {
                 r = dhcp_validate_duid_len(duid_type, duid_len);
                 if (r < 0)
                         return r;
+        }
+
+        if (duid != NULL) {
                 client->duid.type = htobe16(duid_type);
                 memcpy(&client->duid.raw.data, duid, duid_len);
-                client->duid_len = duid_len + sizeof(client->duid.type);
-        }
+                client->duid_len = sizeof(client->duid.type) + duid_len;
+        } else if (duid_type == DUID_TYPE_EN) {
+                r = dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
+                if (r < 0)
+                        return r;
+        } else
+                return -EOPNOTSUPP;
 
         return 0;
 }
@@ -427,8 +451,7 @@ static int client_send_message(sd_dhcp6_client *client, usec_t time_now) {
         return 0;
 }
 
-static int client_timeout_t2(sd_event_source *s, uint64_t usec,
-                             void *userdata) {
+static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp6_client *client = userdata;
 
         assert_return(s, -EINVAL);
@@ -445,8 +468,7 @@ static int client_timeout_t2(sd_event_source *s, uint64_t usec,
         return 0;
 }
 
-static int client_timeout_t1(sd_event_source *s, uint64_t usec,
-                             void *userdata) {
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp6_client *client = userdata;
 
         assert_return(s, -EINVAL);
@@ -463,8 +485,7 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec,
         return 0;
 }
 
-static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec,
-                                        void *userdata) {
+static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec, void *userdata) {
         sd_dhcp6_client *client = userdata;
         DHCP6_CLIENT_DONT_DESTROY(client);
         enum DHCP6State state;
@@ -490,8 +511,7 @@ static usec_t client_timeout_compute_random(usec_t val) {
                 (random_u32() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
 }
 
-static int client_timeout_resend(sd_event_source *s, uint64_t usec,
-                                 void *userdata) {
+static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) {
         int r = 0;
         sd_dhcp6_client *client = userdata;
         usec_t time_now, init_retransmit_time = 0, max_retransmit_time = 0;
@@ -658,9 +678,11 @@ static int client_ensure_iaid(sd_dhcp6_client *client) {
         return 0;
 }
 
-static int client_parse_message(sd_dhcp6_client *client,
-                                DHCP6Message *message, size_t len,
-                                sd_dhcp6_lease *lease) {
+static int client_parse_message(
+                sd_dhcp6_client *client,
+                DHCP6Message *message,
+                size_t len,
+                sd_dhcp6_lease *lease) {
         int r;
         uint8_t *optval, *option, *id = NULL;
         uint16_t optcode, status;
diff --git a/src/network/networkd-address-pool.h b/src/network/networkd-address-pool.h
index 8e1378ff40..af30decfe0 100644
--- a/src/network/networkd-address-pool.h
+++ b/src/network/networkd-address-pool.h
@@ -22,7 +22,9 @@
 typedef struct AddressPool AddressPool;
 
 #include "in-addr-util.h"
-#include "networkd.h"
+#include "list.h"
+
+typedef struct Manager Manager;
 
 struct AddressPool {
         Manager *manager;
diff --git a/src/network/networkd-address.h b/src/network/networkd-address.h
index 3c81978fb1..784ab18b27 100644
--- a/src/network/networkd-address.h
+++ b/src/network/networkd-address.h
@@ -28,10 +28,12 @@ typedef struct Address Address;
 
 #include "networkd-link.h"
 #include "networkd-network.h"
-#include "networkd.h"
 
 #define CACHE_INFO_INFINITY_LIFE_TIME 0xFFFFFFFFU
 
+typedef struct Network Network;
+typedef struct Link Link;
+
 struct Address {
         Network *network;
         unsigned section;
diff --git a/src/network/networkd-conf.c b/src/network/networkd-conf.c
index 70f0121d6d..6072c1e2de 100644
--- a/src/network/networkd-conf.c
+++ b/src/network/networkd-conf.c
@@ -37,11 +37,10 @@ int manager_parse_config_file(Manager *m) {
 }
 
 static const char* const duid_type_table[_DUID_TYPE_MAX] = {
-        [DUID_TYPE_RAW]  = "raw",
         [DUID_TYPE_LLT]  = "link-layer-time",
         [DUID_TYPE_EN]   = "vendor",
         [DUID_TYPE_LL]   = "link-layer",
-        [DUID_TYPE_UUID] = "uuid"
+        [DUID_TYPE_UUID] = "uuid",
 };
 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_FROM_STRING(duid_type, DUIDType);
 DEFINE_CONFIG_PARSE_ENUM(config_parse_duid_type, duid_type, DUIDType, "Failed to parse DUID type");
@@ -58,69 +57,29 @@ int config_parse_duid_rawdata(
                 void *data,
                 void *userdata) {
 
-        int r;
-        char *cbyte;
-        const char *pduid = rvalue;
-        Manager *m = userdata;
-        Network *n = userdata;
-        DUIDType duidtype;
-        uint16_t dhcp_duid_type = 0;
-        uint8_t dhcp_duid[MAX_DUID_LEN];
-        size_t len, count = 0, duid_start_offset = 0, dhcp_duid_len = 0;
+        DUID *ret = data;
+        uint8_t raw_data[MAX_DUID_LEN];
+        unsigned count = 0;
 
         assert(filename);
         assert(lvalue);
         assert(rvalue);
-        assert(userdata);
+        assert(ret);
 
-        duidtype = (ltype == DUID_CONFIG_SOURCE_GLOBAL) ? m->duid_type : n->duid_type;
-
-        if (duidtype == _DUID_TYPE_INVALID)
-                duidtype = DUID_TYPE_RAW;
-
-        switch (duidtype) {
-
-        case DUID_TYPE_LLT:
-                /* RawData contains DUID-LLT link-layer address (offset 6) */
-                duid_start_offset = 6;
-                break;
-
-        case DUID_TYPE_EN:
-                /* RawData contains DUID-EN identifier (offset 4) */
-                duid_start_offset = 4;
-                break;
-
-        case DUID_TYPE_LL:
-                /* RawData contains DUID-LL link-layer address (offset 2) */
-                duid_start_offset = 2;
-                break;
-
-        case DUID_TYPE_UUID:
-                /* RawData specifies UUID (offset 0) - fall thru */
-
-        case DUID_TYPE_RAW:
-                /* First two bytes of RawData is DUID Type - fall thru */
-
-        default:
-                break;
-        }
-
-        if (duidtype != DUID_TYPE_RAW)
-                dhcp_duid_type = (uint16_t) duidtype;
-
-        /* RawData contains DUID in format " NN:NN:NN... " */
+        /* RawData contains DUID in format "NN:NN:NN..." */
         for (;;) {
-                int n1, n2;
+                int n1, n2, len, r;
                 uint32_t byte;
+                char *cbyte;
 
-                r = extract_first_word(&pduid, &cbyte, ":", 0);
+                r = extract_first_word(&rvalue, &cbyte, ":", 0);
                 if (r < 0) {
                         log_syntax(unit, LOG_ERR, filename, line, r, "Failed to read DUID, ignoring assignment: %s.", rvalue);
                         return 0;
                 }
                 if (r == 0)
                         break;
-                if (duid_start_offset + dhcp_duid_len >= MAX_DUID_LEN) {
+                if (count >= MAX_DUID_LEN) {
                         log_syntax(unit, LOG_ERR, filename, line, 0, "Max DUID length exceeded, ignoring assignment: %s.", rvalue);
                         return 0;
                 }
@@ -142,30 +101,11 @@ int config_parse_duid_rawdata(
                 }
 
                 byte = ((uint8_t) n1 << (4 * (len-1))) | (uint8_t) n2;
-
-                /* If DUID_TYPE_RAW, first two bytes hold DHCP DUID type code */
-                if (duidtype == DUID_TYPE_RAW && count < 2) {
-                        dhcp_duid_type |= (byte << (8 * (1 - count)));
-                        count++;
-                        continue;
-                }
-
-                dhcp_duid[duid_start_offset + dhcp_duid_len] = byte;
-                dhcp_duid_len++;
-        }
-
-        if (ltype == DUID_CONFIG_SOURCE_GLOBAL) {
-                m->duid_type = duidtype;
-                m->dhcp_duid_type = dhcp_duid_type;
-                m->dhcp_duid_len = dhcp_duid_len;
-                memcpy(&m->dhcp_duid[duid_start_offset], dhcp_duid, dhcp_duid_len);
-        } else {
-                /* DUID_CONFIG_SOURCE_NETWORK */
-                n->duid_type = duidtype;
-                n->dhcp_duid_type = dhcp_duid_type;
-                n->dhcp_duid_len = dhcp_duid_len;
-                memcpy(&n->dhcp_duid[duid_start_offset], dhcp_duid, dhcp_duid_len);
+                raw_data[count++] = byte;
         }
 
+        assert_cc(sizeof(raw_data) == sizeof(ret->raw_data));
+        memcpy(ret->raw_data, raw_data, count);
+        ret->raw_data_len = count;
         return 0;
 }
diff --git a/src/network/networkd-conf.h b/src/network/networkd-conf.h
index 671e656d7b..c7bfb42a72 100644
--- a/src/network/networkd-conf.h
+++ b/src/network/networkd-conf.h
@@ -21,14 +21,29 @@
 
 #include "networkd.h"
 
-typedef enum DuidConfigSource {
-        DUID_CONFIG_SOURCE_GLOBAL = 0,
-        DUID_CONFIG_SOURCE_NETWORK,
-} DuidConfigSource;
-
 int manager_parse_config_file(Manager *m);
 
 const struct ConfigPerfItem* networkd_gperf_lookup(const char *key, unsigned length);
 
-int config_parse_duid_type(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);
-int config_parse_duid_rawdata(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);
+int config_parse_duid_type(
+                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);
+int config_parse_duid_rawdata(
+                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);
diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index c5b61abc9e..89926e8a7e 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -24,7 +24,7 @@
 #include "dhcp-lease-internal.h"
 #include "hostname-util.h"
 #include "network-internal.h"
-#include "networkd-link.h"
+#include "networkd.h"
 
 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m,
                                void *userdata) {
@@ -628,28 +628,24 @@ int dhcp4_configure(Link *link) {
         }
 
         switch (link->network->dhcp_client_identifier) {
-        case DHCP_CLIENT_ID_DUID:
+        case DHCP_CLIENT_ID_DUID: {
                 /* If configured, apply user specified DUID and/or IAID */
-                if (link->network->duid_type != _DUID_TYPE_INVALID)
-                        r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
-                                                         link->network->iaid,
-                                                         link->network->dhcp_duid_type,
-                                                         link->network->dhcp_duid,
-                                                         link->network->dhcp_duid_len);
-                else
-                        r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
-                                                         link->network->iaid,
-                                                         link->manager->dhcp_duid_type,
-                                                         link->manager->dhcp_duid,
-                                                         link->manager->dhcp_duid_len);
+                const DUID *duid = link_duid(link);
+
+                r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
+                                                 link->network->iaid,
+                                                 duid->type,
+                                                 duid->raw_data_len > 0 ? duid->raw_data : NULL,
+                                                 duid->raw_data_len);
                 if (r < 0)
                         return r;
                 break;
+        }
         case DHCP_CLIENT_ID_MAC:
                 r = sd_dhcp_client_set_client_id(link->dhcp_client,
                                                  ARPHRD_ETHER,
                                                  (const uint8_t *) &link->mac,
-                                                 sizeof (link->mac));
+                                                 sizeof(link->mac));
                 if (r < 0)
                         return r;
                 break;
diff --git a/src/network/networkd-dhcp6.c b/src/network/networkd-dhcp6.c
index d4b2fbfc57..ccca4e9522 100644
--- a/src/network/networkd-dhcp6.c
+++ b/src/network/networkd-dhcp6.c
@@ -23,7 +23,7 @@
 #include "sd-dhcp6-client.h"
 
 #include "network-internal.h"
-#include "networkd-link.h"
+#include "networkd.h"
 
 static int dhcp6_lease_address_acquired(sd_dhcp6_client *client, Link *link);
 
@@ -206,6 +206,7 @@ int dhcp6_request_address(Link *link) {
 int dhcp6_configure(Link *link) {
         sd_dhcp6_client *client = NULL;
         int r;
+        const DUID *duid;
 
         assert(link);
 
@@ -234,16 +235,11 @@ int dhcp6_configure(Link *link) {
         if (r < 0)
                 goto error;
 
-        if (link->network->duid_type != _DUID_TYPE_INVALID)
-                r = sd_dhcp6_client_set_duid(client,
-                                             link->network->dhcp_duid_type,
-                                             link->network->dhcp_duid,
-                                             link->network->dhcp_duid_len);
-        else
-                r = sd_dhcp6_client_set_duid(client,
-                                             link->manager->dhcp_duid_type,
-                                             link->manager->dhcp_duid,
-                                             link->manager->dhcp_duid_len);
+        duid = link_duid(link);
+        r = sd_dhcp6_client_set_duid(client,
+                                     duid->type,
+                                     duid->raw_data_len > 0 ? duid->raw_data : NULL,
+                                     duid->raw_data_len);
         if (r < 0)
                 goto error;
 
diff --git a/src/network/networkd-fdb.h b/src/network/networkd-fdb.h
index 89b3e29405..84410714f5 100644
--- a/src/network/networkd-fdb.h
+++ b/src/network/networkd-fdb.h
@@ -19,10 +19,12 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-typedef struct FdbEntry FdbEntry;
+#include "list.h"
+#include "macro.h"
 
-#include "networkd-network.h"
-#include "networkd.h"
+typedef struct Network Network;
+typedef struct FdbEntry FdbEntry;
+typedef struct Link Link;
 
 struct FdbEntry {
         Network *network;
diff --git a/src/network/networkd-gperf.gperf b/src/network/networkd-gperf.gperf
index afc71b4cb8..3fdfe74955 100644
--- a/src/network/networkd-gperf.gperf
+++ b/src/network/networkd-gperf.gperf
@@ -14,5 +14,5 @@ struct ConfigPerfItem;
 %struct-type
 %includes
 %%
-DHCP.DUIDType,              config_parse_duid_type,                 0,                                  offsetof(Manager, duid_type)
-DHCP.DUIDRawData,           config_parse_duid_rawdata,              DUID_CONFIG_SOURCE_GLOBAL,          offsetof(Manager, dhcp_duid)
+DHCP.DUIDType,              config_parse_duid_type,                 0,          offsetof(Manager, duid.type)
+DHCP.DUIDRawData,           config_parse_duid_rawdata,              0,          offsetof(Manager, duid)
diff --git a/src/network/networkd-ipv4ll.c b/src/network/networkd-ipv4ll.c
index e05fd3eea7..35c9b06473 100644
--- a/src/network/networkd-ipv4ll.c
+++ b/src/network/networkd-ipv4ll.c
@@ -21,7 +21,7 @@
 #include <linux/if.h>
 
 #include "network-internal.h"
-#include "networkd-link.h"
+#include "networkd.h"
 
 static int ipv4ll_address_lost(Link *link) {
         _cleanup_address_free_ Address *address = NULL;
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 5fc513bfda..c646af1f1a 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -28,9 +28,8 @@
 #include "fileio.h"
 #include "netlink-util.h"
 #include "network-internal.h"
-#include "networkd-link.h"
+#include "networkd.h"
 #include "networkd-lldp-tx.h"
-#include "networkd-netdev.h"
 #include "set.h"
 #include "socket-util.h"
 #include "stdio-util.h"
@@ -2880,6 +2879,8 @@ int link_update(Link *link, sd_netlink_message *m) {
                         }
 
                         if (link->dhcp_client) {
+                                const DUID *duid = link_duid(link);
+
                                 r = sd_dhcp_client_set_mac(link->dhcp_client,
                                                            (const uint8_t *) &link->mac,
                                                            sizeof (link->mac),
@@ -2887,23 +2888,18 @@ int link_update(Link *link, sd_netlink_message *m) {
                                 if (r < 0)
                                         return log_link_warning_errno(link, r, "Could not update MAC address in DHCP client: %m");
 
-                                if (link->network->duid_type != _DUID_TYPE_INVALID)
-                                        r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
-                                                                         link->network->iaid,
-                                                                         link->network->dhcp_duid_type,
-                                                                         link->network->dhcp_duid,
-                                                                         link->network->dhcp_duid_len);
-                                else
-                                        r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
-                                                                         link->network->iaid,
-                                                                         link->manager->dhcp_duid_type,
-                                                                         link->manager->dhcp_duid,
-                                                                         link->manager->dhcp_duid_len);
+                                r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
+                                                                 link->network->iaid,
+                                                                 duid->type,
+                                                                 duid->raw_data_len > 0 ? duid->raw_data : NULL,
+                                                                 duid->raw_data_len);
                                 if (r < 0)
                                         return log_link_warning_errno(link, r, "Could not update DUID/IAID in DHCP client: %m");
                         }
 
                         if (link->dhcp6_client) {
+                                const DUID* duid = link_duid(link);
+
                                 r = sd_dhcp6_client_set_mac(link->dhcp6_client,
                                                             (const uint8_t *) &link->mac,
                                                             sizeof (link->mac),
@@ -2916,16 +2912,10 @@ int link_update(Link *link, sd_netlink_message *m) {
                                 if (r < 0)
                                         return log_link_warning_errno(link, r, "Could not update DHCPv6 IAID: %m");
 
-                                if (link->network->duid_type != _DUID_TYPE_INVALID)
-                                        r = sd_dhcp6_client_set_duid(link->dhcp6_client,
-                                                                     link->network->dhcp_duid_type,
-                                                                     link->network->dhcp_duid,
-                                                                     link->network->dhcp_duid_len);
-                                else
-                                        r = sd_dhcp6_client_set_duid(link->dhcp6_client,
-                                                                     link->manager->dhcp_duid_type,
-                                                                     link->manager->dhcp_duid,
-                                                                     link->manager->dhcp_duid_len);
+                                r = sd_dhcp6_client_set_duid(link->dhcp6_client,
+                                                             duid->type,
+                                                             duid->raw_data_len > 0 ? duid->raw_data : NULL,
+                                                             duid->raw_data_len);
                                 if (r < 0)
                                         return log_link_warning_errno(link, r, "Could not update DHCPv6 DUID: %m");
                         }
diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index f2a64ca9b5..86139be557 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -21,14 +21,17 @@
 
 #include <endian.h>
 
+#include "sd-bus.h"
 #include "sd-dhcp-client.h"
 #include "sd-dhcp-server.h"
 #include "sd-dhcp6-client.h"
 #include "sd-ipv4ll.h"
 #include "sd-lldp.h"
 #include "sd-ndisc.h"
+#include "sd-netlink.h"
 
-typedef struct Link Link;
+#include "list.h"
+#include "set.h"
 
 typedef enum LinkState {
         LINK_STATE_PENDING,
@@ -54,11 +57,11 @@ typedef enum LinkOperationalState {
         _LINK_OPERSTATE_INVALID = -1
 } LinkOperationalState;
 
-#include "networkd-address.h"
-#include "networkd-network.h"
-#include "networkd.h"
+typedef struct Manager Manager;
+typedef struct Network Network;
+typedef struct Address Address;
 
-struct Link {
+typedef struct Link {
         Manager *manager;
 
         int n_ref;
@@ -122,7 +125,7 @@ struct Link {
 
         Hashmap *bound_by_links;
         Hashmap *bound_to_links;
-};
+} Link;
 
 Link *link_unref(Link *link);
 Link *link_ref(Link *link);
diff --git a/src/network/networkd-lldp-tx.c b/src/network/networkd-lldp-tx.c
index 6bde04bc32..03b694c3f1 100644
--- a/src/network/networkd-lldp-tx.c
+++ b/src/network/networkd-lldp-tx.c
@@ -21,15 +21,18 @@
 #include <inttypes.h>
 #include <string.h>
 
+#include "alloc-util.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "hostname-util.h"
-#include "networkd-lldp-tx.h"
 #include "random-util.h"
 #include "socket-util.h"
 #include "string-util.h"
 #include "unaligned.h"
 
+#include "networkd.h"
+#include "networkd-lldp-tx.h"
+
 #define LLDP_MULTICAST_ADDR { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x0e }
 
 /* The LLDP spec calls this "txFastInit", see 9.2.5.19 */
diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index d355aaa19c..5dcd4df536 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -1037,7 +1037,7 @@ int manager_new(Manager **ret) {
         if (r < 0)
                 return r;
 
-        m->duid_type = _DUID_TYPE_INVALID;
+        m->duid.type = DUID_TYPE_EN;
 
         *ret = m;
         m = NULL;
diff --git a/src/network/networkd-ndisc.c b/src/network/networkd-ndisc.c
index 4577292e44..b22c58bfe5 100644
--- a/src/network/networkd-ndisc.c
+++ b/src/network/networkd-ndisc.c
@@ -24,7 +24,7 @@
 
 #include "sd-ndisc.h"
 
-#include "networkd-link.h"
+#include "networkd.h"
 
 static int ndisc_netlink_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
         _cleanup_link_unref_ Link *link = userdata;
diff --git a/src/network/networkd-netdev-bond.c b/src/network/networkd-netdev-bond.c
index 6b9cbcded6..7913b0088e 100644
--- a/src/network/networkd-netdev-bond.c
+++ b/src/network/networkd-netdev-bond.c
@@ -25,6 +25,7 @@
 
 #include "alloc-util.h"
 #include "conf-parser.h"
+#include "extract-word.h"
 #include "missing.h"
 #include "networkd-netdev-bond.h"
 #include "string-table.h"
diff --git a/src/network/networkd-netdev-bond.h b/src/network/networkd-netdev-bond.h
index cb6baea24f..b941edb344 100644
--- a/src/network/networkd-netdev-bond.h
+++ b/src/network/networkd-netdev-bond.h
@@ -20,8 +20,7 @@
 ***/
 
 #include "in-addr-util.h"
-
-typedef struct Bond Bond;
+#include "list.h"
 
 #include "networkd-netdev.h"
 
@@ -106,7 +105,7 @@ typedef struct ArpIpTarget {
         LIST_FIELDS(struct ArpIpTarget, arp_ip_target);
 } ArpIpTarget;
 
-struct Bond {
+typedef struct Bond {
         NetDev meta;
 
         BondMode mode;
@@ -133,8 +132,9 @@ struct Bond {
 
         int n_arp_ip_targets;
         ArpIpTarget *arp_ip_targets;
-};
+} Bond;
 
+DEFINE_NETDEV_CAST(BOND, Bond);
 extern const NetDevVTable bond_vtable;
 
 const char *bond_mode_to_string(BondMode d) _const_;
diff --git a/src/network/networkd-netdev-bridge.c b/src/network/networkd-netdev-bridge.c
index 3f91b2eaea..3e44dd7960 100644
--- a/src/network/networkd-netdev-bridge.c
+++ b/src/network/networkd-netdev-bridge.c
@@ -22,6 +22,7 @@
 
 #include "missing.h"
 #include "netlink-util.h"
+#include "networkd.h"
 #include "networkd-netdev-bridge.h"
 
 /* callback for brige netdev's parameter set */
diff --git a/src/network/networkd-netdev-bridge.h b/src/network/networkd-netdev-bridge.h
index 3f6f1d0502..b921439f02 100644
--- a/src/network/networkd-netdev-bridge.h
+++ b/src/network/networkd-netdev-bridge.h
@@ -19,11 +19,9 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-typedef struct Bridge Bridge;
-
 #include "networkd-netdev.h"
 
-struct Bridge {
+typedef struct Bridge {
         NetDev meta;
 
         int mcast_querier;
@@ -31,6 +29,7 @@ struct Bridge {
         usec_t forward_delay;
         usec_t hello_time;
         usec_t max_age;
-};
+} Bridge;
 
+DEFINE_NETDEV_CAST(BRIDGE, Bridge);
 extern const NetDevVTable bridge_vtable;
diff --git a/src/network/networkd-netdev-dummy.h b/src/network/networkd-netdev-dummy.h
index 42da62ebe4..efe302267e 100644
--- a/src/network/networkd-netdev-dummy.h
+++ b/src/network/networkd-netdev-dummy.h
@@ -19,12 +19,11 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-typedef struct Dummy Dummy;
-
 #include "networkd-netdev.h"
 
-struct Dummy {
+typedef struct Dummy {
         NetDev meta;
-};
+} Dummy;
 
+DEFINE_NETDEV_CAST(DUMMY, Dummy);
 extern const NetDevVTable dummy_vtable;
diff --git a/src/network/networkd-netdev-gperf.gperf b/src/network/networkd-netdev-gperf.gperf
index 15a787a9e3..1ebd0fdf20 100644
--- a/src/network/networkd-netdev-gperf.gperf
+++ b/src/network/networkd-netdev-gperf.gperf
@@ -1,11 +1,17 @@
 %{
 #include <stddef.h>
 #include "conf-parser.h"
-#include "networkd-netdev.h"
-#include "networkd-netdev-tunnel.h"
+#include "network-internal.h"
 #include "networkd-netdev-bond.h"
+#include "networkd-netdev-ipvlan.h"
 #include "networkd-netdev-macvlan.h"
-#include "network-internal.h"
+#include "networkd-netdev-tunnel.h"
+#include "networkd-netdev-tuntap.h"
+#include "networkd-netdev-veth.h"
+#include "networkd-netdev-vlan.h"
+#include "networkd-netdev-vxlan.h"
+#include "networkd-netdev-bridge.h"
+#include "networkd-netdev.h"
 %}
 struct ConfigPerfItem;
 %null_strings
diff --git a/src/network/networkd-netdev-ipvlan.h b/src/network/networkd-netdev-ipvlan.h
index 4bd0b67866..10d4079844 100644
--- a/src/network/networkd-netdev-ipvlan.h
+++ b/src/network/networkd-netdev-ipvlan.h
@@ -19,8 +19,6 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-typedef struct IPVlan IPVlan;
-
 #include "missing.h"
 #include "networkd-netdev.h"
 
@@ -31,12 +29,13 @@ typedef enum IPVlanMode {
         _NETDEV_IPVLAN_MODE_INVALID = -1
 } IPVlanMode;
 
-struct IPVlan {
+typedef struct IPVlan {
         NetDev meta;
 
         IPVlanMode mode;
-};
+} IPVlan;
 
+DEFINE_NETDEV_CAST(IPVLAN, IPVlan);
 extern const NetDevVTable ipvlan_vtable;
 
 const char *ipvlan_mode_to_string(IPVlanMode d) _const_;
diff --git a/src/network/networkd-netdev-macvlan.h b/src/network/networkd-netdev-macvlan.h
index 622ef9ef53..3663f4f051 100644
--- a/src/network/networkd-netdev-macvlan.h
+++ b/src/network/networkd-netdev-macvlan.h
@@ -38,6 +38,8 @@ struct MacVlan {
         MacVlanMode mode;
 };
 
+DEFINE_NETDEV_CAST(MACVLAN, MacVlan);
+DEFINE_NETDEV_CAST(MACVTAP, MacVlan);
 extern const NetDevVTable macvlan_vtable;
 extern const NetDevVTable macvtap_vtable;
 
diff --git a/src/network/networkd-netdev-tunnel.h b/src/network/networkd-netdev-tunnel.h
index 0d41f80a3c..7d31e7b687 100644
--- a/src/network/networkd-netdev-tunnel.h
+++ b/src/network/networkd-netdev-tunnel.h
@@ -19,7 +19,7 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-typedef struct Tunnel Tunnel;
+#include "in-addr-util.h"
 
 #include "networkd-netdev.h"
 
@@ -37,7 +37,7 @@ typedef enum IPv6FlowLabel {
         _NETDEV_IPV6_FLOWLABEL_INVALID = -1,
 } IPv6FlowLabel;
 
-struct Tunnel {
+typedef struct Tunnel {
         NetDev meta;
 
         uint8_t encap_limit;
@@ -56,8 +56,17 @@ struct Tunnel {
 
         bool pmtudisc;
         bool copy_dscp;
-};
-
+} Tunnel;
+
+DEFINE_NETDEV_CAST(IPIP, Tunnel);
+DEFINE_NETDEV_CAST(GRE, Tunnel);
+DEFINE_NETDEV_CAST(GRETAP, Tunnel);
+DEFINE_NETDEV_CAST(IP6GRE, Tunnel);
+DEFINE_NETDEV_CAST(IP6GRETAP, Tunnel);
+DEFINE_NETDEV_CAST(SIT, Tunnel);
+DEFINE_NETDEV_CAST(VTI, Tunnel);
+DEFINE_NETDEV_CAST(VTI6, Tunnel);
+DEFINE_NETDEV_CAST(IP6TNL, Tunnel);
 extern const NetDevVTable ipip_vtable;
 extern const NetDevVTable sit_vtable;
 extern const NetDevVTable vti_vtable;
diff --git a/src/network/networkd-netdev-tuntap.c b/src/network/networkd-netdev-tuntap.c
index 32917fe6d5..088a4d8d32 100644
--- a/src/network/networkd-netdev-tuntap.c
+++ b/src/network/networkd-netdev-tuntap.c
@@ -17,10 +17,13 @@
     along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <net/if.h>
-#include <sys/ioctl.h>
+#include <fcntl.h>
 #include <linux/if_tun.h>
+#include <net/if.h>
 #include <netinet/if_ether.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"
diff --git a/src/network/networkd-netdev-tuntap.h b/src/network/networkd-netdev-tuntap.h
index cbb7ee05a6..120f00a353 100644
--- a/src/network/networkd-netdev-tuntap.h
+++ b/src/network/networkd-netdev-tuntap.h
@@ -34,5 +34,7 @@ struct TunTap {
         bool vnet_hdr;
 };
 
+DEFINE_NETDEV_CAST(TUN, TunTap);
+DEFINE_NETDEV_CAST(TAP, TunTap);
 extern const NetDevVTable tun_vtable;
 extern const NetDevVTable tap_vtable;
diff --git a/src/network/networkd-netdev-veth.h b/src/network/networkd-netdev-veth.h
index ae5785783c..e69bfbc8f0 100644
--- a/src/network/networkd-netdev-veth.h
+++ b/src/network/networkd-netdev-veth.h
@@ -30,4 +30,5 @@ struct Veth {
         struct ether_addr *mac_peer;
 };
 
+DEFINE_NETDEV_CAST(VETH, Veth);
 extern const NetDevVTable veth_vtable;
diff --git a/src/network/networkd-netdev-vlan.h b/src/network/networkd-netdev-vlan.h
index 1de6a1cc36..73aacf4a0f 100644
--- a/src/network/networkd-netdev-vlan.h
+++ b/src/network/networkd-netdev-vlan.h
@@ -31,4 +31,5 @@ struct VLan {
         uint64_t id;
 };
 
+DEFINE_NETDEV_CAST(VLAN, VLan);
 extern const NetDevVTable vlan_vtable;
diff --git a/src/network/networkd-netdev-vxlan.c b/src/network/networkd-netdev-vxlan.c
index dabbd97c87..724f9861be 100644
--- a/src/network/networkd-netdev-vxlan.c
+++ b/src/network/networkd-netdev-vxlan.c
@@ -23,8 +23,10 @@
 
 #include "conf-parser.h"
 #include "alloc-util.h"
+#include "extract-word.h"
 #include "parse-util.h"
 #include "missing.h"
+
 #include "networkd-link.h"
 #include "networkd-netdev-vxlan.h"
 
diff --git a/src/network/networkd-netdev-vxlan.h b/src/network/networkd-netdev-vxlan.h
index a4bb44635a..4614c66fd1 100644
--- a/src/network/networkd-netdev-vxlan.h
+++ b/src/network/networkd-netdev-vxlan.h
@@ -55,6 +55,7 @@ struct VxLan {
         struct ifla_vxlan_port_range port_range;
 };
 
+DEFINE_NETDEV_CAST(VXLAN, VxLan);
 extern const NetDevVTable vxlan_vtable;
 
 int config_parse_vxlan_group_address(const char *unit,
diff --git a/src/network/networkd-netdev.h b/src/network/networkd-netdev.h
index 7ea825fcb4..20244c0309 100644
--- a/src/network/networkd-netdev.h
+++ b/src/network/networkd-netdev.h
@@ -19,15 +19,13 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include "list.h"
-
-typedef struct NetDev NetDev;
-typedef struct NetDevVTable NetDevVTable;
+#include "sd-netlink.h"
 
-#include "networkd-link.h"
-#include "networkd.h"
+#include "list.h"
+#include "time-util.h"
 
 typedef struct netdev_join_callback netdev_join_callback;
+typedef struct Link Link;
 
 struct netdev_join_callback {
         sd_netlink_message_handler_t callback;
@@ -78,7 +76,10 @@ typedef enum NetDevCreateType {
         _NETDEV_CREATE_INVALID = -1,
 } NetDevCreateType;
 
-struct NetDev {
+typedef struct Manager Manager;
+typedef struct Condition Condition;
+
+typedef struct NetDev {
         Manager *manager;
 
         int n_ref;
@@ -99,20 +100,9 @@ struct NetDev {
         int ifindex;
 
         LIST_HEAD(netdev_join_callback, callbacks);
-};
+} NetDev;
 
-#include "networkd-netdev-bond.h"
-#include "networkd-netdev-bridge.h"
-#include "networkd-netdev-dummy.h"
-#include "networkd-netdev-ipvlan.h"
-#include "networkd-netdev-macvlan.h"
-#include "networkd-netdev-tunnel.h"
-#include "networkd-netdev-tuntap.h"
-#include "networkd-netdev-veth.h"
-#include "networkd-netdev-vlan.h"
-#include "networkd-netdev-vxlan.h"
-
-struct NetDevVTable {
+typedef struct NetDevVTable {
         /* How much memory does an object of this unit type need */
         size_t object_size;
 
@@ -144,14 +134,14 @@ struct NetDevVTable {
 
         /* verify that compulsory configuration options were specified */
         int (*config_verify)(NetDev *netdev, const char *filename);
-};
+} NetDevVTable;
 
 extern const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX];
 
 #define NETDEV_VTABLE(n) netdev_vtable[(n)->kind]
 
 /* For casting a netdev into the various netdev kinds */
-#define DEFINE_CAST(UPPERCASE, MixedCase)                                   \
+#define DEFINE_NETDEV_CAST(UPPERCASE, MixedCase)                            \
         static inline MixedCase* UPPERCASE(NetDev *n) {                     \
                 if (_unlikely_(!n || n->kind != NETDEV_KIND_##UPPERCASE))   \
                         return NULL;                                        \
@@ -162,27 +152,6 @@ extern const NetDevVTable * const netdev_vtable[_NETDEV_KIND_MAX];
 /* For casting the various netdev kinds into a netdev */
 #define NETDEV(n) (&(n)->meta)
 
-DEFINE_CAST(BRIDGE, Bridge);
-DEFINE_CAST(BOND, Bond);
-DEFINE_CAST(VLAN, VLan);
-DEFINE_CAST(MACVLAN, MacVlan);
-DEFINE_CAST(MACVTAP, MacVlan);
-DEFINE_CAST(IPVLAN, IPVlan);
-DEFINE_CAST(VXLAN, VxLan);
-DEFINE_CAST(IPIP, Tunnel);
-DEFINE_CAST(GRE, Tunnel);
-DEFINE_CAST(GRETAP, Tunnel);
-DEFINE_CAST(IP6GRE, Tunnel);
-DEFINE_CAST(IP6GRETAP, Tunnel);
-DEFINE_CAST(SIT, Tunnel);
-DEFINE_CAST(VTI, Tunnel);
-DEFINE_CAST(VTI6, Tunnel);
-DEFINE_CAST(IP6TNL, Tunnel);
-DEFINE_CAST(VETH, Veth);
-DEFINE_CAST(DUMMY, Dummy);
-DEFINE_CAST(TUN, TunTap);
-DEFINE_CAST(TAP, TunTap);
-
 int netdev_load(Manager *manager);
 void netdev_drop(NetDev *netdev);
 
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 550b5e5240..51e750b299 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -85,8 +85,8 @@ DHCP.Hostname,                          config_parse_hostname,
 DHCP.RequestBroadcast,                  config_parse_bool,                              0,                             offsetof(Network, dhcp_broadcast)
 DHCP.CriticalConnection,                config_parse_bool,                              0,                             offsetof(Network, dhcp_critical)
 DHCP.VendorClassIdentifier,             config_parse_string,                            0,                             offsetof(Network, dhcp_vendor_class_identifier)
-DHCP.DUIDType,                          config_parse_duid_type,                         0,                             offsetof(Network, duid_type)
-DHCP.DUIDRawData,                       config_parse_duid_rawdata,                      DUID_CONFIG_SOURCE_NETWORK,    offsetof(Network, dhcp_duid)
+DHCP.DUIDType,                          config_parse_duid_type,                         0,                             offsetof(Network, duid.type)
+DHCP.DUIDRawData,                       config_parse_duid_rawdata,                      0,                             offsetof(Network, duid)
 DHCP.RouteMetric,                       config_parse_unsigned,                          0,                             offsetof(Network, dhcp_route_metric)
 DHCP.UseTimezone,                       config_parse_bool,                              0,                             offsetof(Network, dhcp_use_timezone)
 DHCPServer.MaxLeaseTimeSec,             config_parse_sec,                               0,                             offsetof(Network, dhcp_server_max_lease_time_usec)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 2ebcdfa744..206c270e50 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -131,7 +131,7 @@ static int network_load_one(Manager *manager, const char *filename) {
         network->ipv6_accept_ra = -1;
         network->ipv6_dad_transmits = -1;
         network->ipv6_hop_limit = -1;
-        network->duid_type = _DUID_TYPE_INVALID;
+        network->duid.type = _DUID_TYPE_INVALID;
         network->proxy_arp = -1;
 
         r = config_parse(NULL, filename, file,
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 15417f4828..ff2414efdd 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -19,18 +19,19 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include "sd-bus.h"
+#include "udev.h"
+
 #include "condition.h"
+#include "dhcp-identifier.h"
+#include "hashmap.h"
 #include "resolve-util.h"
 
-typedef struct Network Network;
-
-#include "dhcp-identifier.h"
 #include "networkd-address.h"
 #include "networkd-fdb.h"
 #include "networkd-netdev.h"
 #include "networkd-route.h"
 #include "networkd-util.h"
-#include "networkd.h"
 
 #define DHCP_ROUTE_METRIC 1024
 #define IPV4LL_ROUTE_METRIC 2048
@@ -67,6 +68,16 @@ typedef enum LLDPMode {
         _LLDP_MODE_INVALID = -1,
 } LLDPMode;
 
+typedef struct DUID {
+        /* Value of Type in [DHCP] section */
+        DUIDType type;
+
+        uint8_t raw_data_len;
+        uint8_t raw_data[MAX_DUID_LEN];
+} DUID;
+
+typedef struct Manager Manager;
+
 struct Network {
         Manager *manager;
 
@@ -147,12 +158,7 @@ struct Network {
         struct ether_addr *mac;
         unsigned mtu;
         uint32_t iaid;
-        /* Value of Type in [DUID] section */
-        DUIDType duid_type;
-        /* DUID type code - RFC 3315 */
-        uint16_t dhcp_duid_type;
-        size_t dhcp_duid_len;
-        uint8_t dhcp_duid[MAX_DUID_LEN];
+        DUID duid;
 
         LLDPMode lldp_mode; /* LLDP reception */
         bool lldp_emit;     /* LLDP transmission */
diff --git a/src/network/networkd-route.h b/src/network/networkd-route.h
index 3ddeea96b7..84d74992c9 100644
--- a/src/network/networkd-route.h
+++ b/src/network/networkd-route.h
@@ -22,7 +22,6 @@
 typedef struct Route Route;
 
 #include "networkd-network.h"
-#include "networkd.h"
 
 struct Route {
         Network *network;
diff --git a/src/network/networkd.h b/src/network/networkd.h
index 72a2438ac8..26d9e7d6e0 100644
--- a/src/network/networkd.h
+++ b/src/network/networkd.h
@@ -24,19 +24,30 @@
 #include "sd-bus.h"
 #include "sd-event.h"
 #include "sd-netlink.h"
+#include "udev.h"
 
+#include "dhcp-identifier.h"
 #include "hashmap.h"
 #include "list.h"
-#include "udev.h"
 
-typedef struct Manager Manager;
-
-#include "dhcp-identifier.h"
 #include "networkd-address-pool.h"
 #include "networkd-link.h"
+#include "networkd-netdev-bond.h"
+#include "networkd-netdev-bridge.h"
+#include "networkd-netdev-dummy.h"
+#include "networkd-netdev-ipvlan.h"
+#include "networkd-netdev-macvlan.h"
+#include "networkd-netdev-tunnel.h"
+#include "networkd-netdev-tuntap.h"
+#include "networkd-netdev-veth.h"
+#include "networkd-netdev-vlan.h"
+#include "networkd-netdev-vlan.h"
+#include "networkd-netdev-vxlan.h"
 #include "networkd-network.h"
 #include "networkd-util.h"
 
+extern const char* const network_dirs[];
+
 struct Manager {
         sd_netlink *rtnl;
         sd_event *event;
@@ -63,17 +74,15 @@ struct Manager {
 
         usec_t network_dirs_ts_usec;
 
-        /* Value of Type in [DUID] section */
-        DUIDType duid_type;
-        /* DUID type code - RFC 3315 */
-        uint16_t dhcp_duid_type;
-        size_t dhcp_duid_len;
-        uint8_t dhcp_duid[MAX_DUID_LEN];
+        DUID duid;
 };
 
-extern const char* const network_dirs[];
-
-/* Manager */
+static inline const DUID* link_duid(const Link *link) {
+        if (link->network->duid.type != _DUID_TYPE_INVALID)
+                return &link->network->duid;
+        else
+                return &link->manager->duid;
+}
 
 extern const sd_bus_vtable manager_vtable[];
 
diff --git a/src/network/test-networkd-conf.c b/src/network/test-networkd-conf.c
new file mode 100644
index 0000000000..8a62a2a567
--- /dev/null
+++ b/src/network/test-networkd-conf.c
@@ -0,0 +1,89 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2016 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "hexdecoct.h"
+#include "log.h"
+#include "macro.h"
+#include "string-util.h"
+
+#include "networkd-conf.h"
+#include "networkd-network.h"
+
+static void test_config_parse_duid_type_one(const char *rvalue, int ret, DUIDType expected) {
+        DUIDType actual = 0;
+        int r;
+
+        r = config_parse_duid_type("network", "filename", 1, "section", 1, "lvalue", 0, rvalue, &actual, NULL);
+        log_info_errno(r, "\"%s\" → %d (%m)", rvalue, actual);
+        assert_se(r == ret);
+        assert_se(expected == actual);
+}
+
+static void test_config_parse_duid_type(void) {
+        test_config_parse_duid_type_one("", 0, 0);
+        test_config_parse_duid_type_one("link-layer-time", 0, DUID_TYPE_LLT);
+        test_config_parse_duid_type_one("vendor", 0, DUID_TYPE_EN);
+        test_config_parse_duid_type_one("link-layer", 0, DUID_TYPE_LL);
+        test_config_parse_duid_type_one("uuid", 0, DUID_TYPE_UUID);
+        test_config_parse_duid_type_one("foo", 0, 0);
+}
+
+static void test_config_parse_duid_rawdata_one(const char *rvalue, int ret, const DUID* expected) {
+        DUID actual = {};
+        int r;
+
+        r = config_parse_duid_rawdata("network", "filename", 1, "section", 1, "lvalue", 0, rvalue, &actual, NULL);
+        log_info_errno(r, "\"%s\" → \"%s\" (%m)",
+                       rvalue, strnull(hexmem(actual.raw_data, actual.raw_data_len)));
+        assert_se(r == ret);
+        if (expected) {
+                assert_se(actual.raw_data_len == expected->raw_data_len);
+                assert_se(memcmp(actual.raw_data, expected->raw_data, expected->raw_data_len) == 0);
+        }
+}
+
+#define BYTES_0_128 "0:1:2:3:4:5:6:7:8:9:a:b:c:d:e:f:10:11:12:13:14:15:16:17:18:19:1a:1b:1c:1d:1e:1f:20:21:22:23:24:25:26:27:28:29:2a:2b:2c:2d:2e:2f:30:31:32:33:34:35:36:37:38:39:3a:3b:3c:3d:3e:3f:40:41:42:43:44:45:46:47:48:49:4a:4b:4c:4d:4e:4f:50:51:52:53:54:55:56:57:58:59:5a:5b:5c:5d:5e:5f:60:61:62:63:64:65:66:67:68:69:6a:6b:6c:6d:6e:6f:70:71:72:73:74:75:76:77:78:79:7a:7b:7c:7d:7e:7f:80"
+
+#define BYTES_1_128 {0x1,0x2,0x3,0x4,0x5,0x6,0x7,0x8,0x9,0xa,0xb,0xc,0xd,0xe,0xf,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f,0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f,0x80}
+
+static void test_config_parse_duid_rawdata(void) {
+        test_config_parse_duid_rawdata_one("", 0, &(DUID){});
+        test_config_parse_duid_rawdata_one("00:11:22:33:44:55:66:77", 0,
+                                           &(DUID){0, 8, {0x00,0x11,0x22,0x33,0x44,0x55,0x66,0x77}});
+        test_config_parse_duid_rawdata_one("00:11:22:", 0,
+                                           &(DUID){0, 3, {0x00,0x11,0x22}});
+        test_config_parse_duid_rawdata_one("000:11:22", 0, &(DUID){}); /* error, output is all zeros */
+        test_config_parse_duid_rawdata_one("00:111:22", 0, &(DUID){});
+        test_config_parse_duid_rawdata_one("0:1:2:3:4:5:6:7", 0,
+                                           &(DUID){0, 8, {0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7}});
+        test_config_parse_duid_rawdata_one("11::", 0, &(DUID){0, 1, {0x11}});  /* FIXME: should this be an error? */
+        test_config_parse_duid_rawdata_one("abcdef", 0, &(DUID){});
+        test_config_parse_duid_rawdata_one(BYTES_0_128, 0, &(DUID){});
+        test_config_parse_duid_rawdata_one(BYTES_0_128 + 2, 0, &(DUID){0, 128, BYTES_1_128});
+}
+
+int main(int argc, char **argv) {
+        log_parse_environment();
+        log_open();
+
+        test_config_parse_duid_type();
+        test_config_parse_duid_rawdata();
+
+        return 0;
+}
diff --git a/src/systemd/sd-dhcp-client.h b/src/systemd/sd-dhcp-client.h
index 374ff8774e..20b8c2873f 100644
--- a/src/systemd/sd-dhcp-client.h
+++ b/src/systemd/sd-dhcp-client.h
@@ -84,28 +84,57 @@ enum {
 
 typedef struct sd_dhcp_client sd_dhcp_client;
 
-typedef void (*sd_dhcp_client_callback_t)(sd_dhcp_client *client, int event,
-                                    void *userdata);
-int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_callback_t cb,
-                                void *userdata);
-
-int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option);
-int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
-                                       const struct in_addr *last_address);
-int sd_dhcp_client_set_request_broadcast(sd_dhcp_client *client, int broadcast);
-int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index);
-int sd_dhcp_client_set_mac(sd_dhcp_client *client, const uint8_t *addr,
-                           size_t addr_len, uint16_t arp_type);
-int sd_dhcp_client_set_client_id(sd_dhcp_client *client, uint8_t type,
-                                 const uint8_t *data, size_t data_len);
-int sd_dhcp_client_set_iaid_duid(sd_dhcp_client *client, uint32_t iaid,
-                                 uint16_t duid_type, uint8_t *duid, size_t duid_len);
-int sd_dhcp_client_get_client_id(sd_dhcp_client *client, uint8_t *type,
-                                 const uint8_t **data, size_t *data_len);
-int sd_dhcp_client_set_mtu(sd_dhcp_client *client, uint32_t mtu);
-int sd_dhcp_client_set_hostname(sd_dhcp_client *client, const char *hostname);
-int sd_dhcp_client_set_vendor_class_identifier(sd_dhcp_client *client, const char *vci);
-int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret);
+typedef void (*sd_dhcp_client_callback_t)(sd_dhcp_client *client, int event, void *userdata);
+int sd_dhcp_client_set_callback(
+                sd_dhcp_client *client,
+                sd_dhcp_client_callback_t cb,
+                void *userdata);
+
+int sd_dhcp_client_set_request_option(
+                sd_dhcp_client *client,
+                uint8_t option);
+int sd_dhcp_client_set_request_address(
+                sd_dhcp_client *client,
+                const struct in_addr *last_address);
+int sd_dhcp_client_set_request_broadcast(
+                sd_dhcp_client *client,
+                int broadcast);
+int sd_dhcp_client_set_index(
+                sd_dhcp_client *client,
+                int interface_index);
+int sd_dhcp_client_set_mac(
+                sd_dhcp_client *client,
+                const uint8_t *addr,
+                size_t addr_len,
+                uint16_t arp_type);
+int sd_dhcp_client_set_client_id(
+                sd_dhcp_client *client,
+                uint8_t type,
+                const uint8_t *data,
+                size_t data_len);
+int sd_dhcp_client_set_iaid_duid(
+                sd_dhcp_client *client,
+                uint32_t iaid,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len);
+int sd_dhcp_client_get_client_id(
+                sd_dhcp_client *client,
+                uint8_t *type,
+                const uint8_t **data,
+                size_t *data_len);
+int sd_dhcp_client_set_mtu(
+                sd_dhcp_client *client,
+                uint32_t mtu);
+int sd_dhcp_client_set_hostname(
+                sd_dhcp_client *client,
+                const char *hostname);
+int sd_dhcp_client_set_vendor_class_identifier(
+                sd_dhcp_client *client,
+                const char *vci);
+int sd_dhcp_client_get_lease(
+                sd_dhcp_client *client,
+                sd_dhcp_lease **ret);
 
 int sd_dhcp_client_stop(sd_dhcp_client *client);
 int sd_dhcp_client_start(sd_dhcp_client *client);
@@ -115,7 +144,10 @@ sd_dhcp_client *sd_dhcp_client_unref(sd_dhcp_client *client);
 
 int sd_dhcp_client_new(sd_dhcp_client **ret);
 
-int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int64_t priority);
+int sd_dhcp_client_attach_event(
+                sd_dhcp_client *client,
+                sd_event *event,
+                int64_t priority);
 int sd_dhcp_client_detach_event(sd_dhcp_client *client);
 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client);
 
diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
index 4604cb6382..90f62eaca4 100644
--- a/src/systemd/sd-dhcp6-client.h
+++ b/src/systemd/sd-dhcp6-client.h
@@ -76,29 +76,52 @@ enum {
 
 typedef struct sd_dhcp6_client sd_dhcp6_client;
 
-typedef void (*sd_dhcp6_client_callback_t)(sd_dhcp6_client *client, int event,
-                                     void *userdata);
-int sd_dhcp6_client_set_callback(sd_dhcp6_client *client,
-                                 sd_dhcp6_client_callback_t cb, void *userdata);
-
-int sd_dhcp6_client_set_index(sd_dhcp6_client *client, int interface_index);
-int sd_dhcp6_client_set_local_address(sd_dhcp6_client *client, const struct in6_addr *local_address);
-int sd_dhcp6_client_set_mac(sd_dhcp6_client *client, const uint8_t *addr,
-                            size_t addr_len, uint16_t arp_type);
-int sd_dhcp6_client_set_duid(sd_dhcp6_client *client, uint16_t duid_type,
-                             uint8_t *duid, size_t duid_len);
-int sd_dhcp6_client_set_iaid(sd_dhcp6_client *client, uint32_t iaid);
-int sd_dhcp6_client_set_information_request(sd_dhcp6_client *client, int enabled);
-int sd_dhcp6_client_get_information_request(sd_dhcp6_client *client, int *enabled);
-int sd_dhcp6_client_set_request_option(sd_dhcp6_client *client,
-                                       uint16_t option);
-
-int sd_dhcp6_client_get_lease(sd_dhcp6_client *client, sd_dhcp6_lease **ret);
+typedef void (*sd_dhcp6_client_callback_t)(sd_dhcp6_client *client, int event, void *userdata);
+int sd_dhcp6_client_set_callback(
+                sd_dhcp6_client *client,
+                sd_dhcp6_client_callback_t cb,
+                void *userdata);
+
+int sd_dhcp6_client_set_index(
+                sd_dhcp6_client *client,
+                int interface_index);
+int sd_dhcp6_client_set_local_address(
+                sd_dhcp6_client *client,
+                const struct in6_addr *local_address);
+int sd_dhcp6_client_set_mac(
+                sd_dhcp6_client *client,
+                const uint8_t *addr,
+                size_t addr_len,
+                uint16_t arp_type);
+int sd_dhcp6_client_set_duid(
+                sd_dhcp6_client *client,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len);
+int sd_dhcp6_client_set_iaid(
+                sd_dhcp6_client *client,
+                uint32_t iaid);
+int sd_dhcp6_client_set_information_request(
+                sd_dhcp6_client *client,
+                int enabled);
+int sd_dhcp6_client_get_information_request(
+                sd_dhcp6_client *client,
+                int *enabled);
+int sd_dhcp6_client_set_request_option(
+                sd_dhcp6_client *client,
+                uint16_t option);
+
+int sd_dhcp6_client_get_lease(
+                sd_dhcp6_client *client,
+                sd_dhcp6_lease **ret);
 
 int sd_dhcp6_client_stop(sd_dhcp6_client *client);
 int sd_dhcp6_client_start(sd_dhcp6_client *client);
 int sd_dhcp6_client_is_running(sd_dhcp6_client *client);
-int sd_dhcp6_client_attach_event(sd_dhcp6_client *client, sd_event *event, int64_t priority);
+int sd_dhcp6_client_attach_event(
+                sd_dhcp6_client *client,
+                sd_event *event,
+                int64_t priority);
 int sd_dhcp6_client_detach_event(sd_dhcp6_client *client);
 sd_event *sd_dhcp6_client_get_event(sd_dhcp6_client *client);
 sd_dhcp6_client *sd_dhcp6_client_ref(sd_dhcp6_client *client);