network: deprecate DuplicateAddressDetection=

And this introduces IPv6DuplicateAddressDetection=.

DuplicateAddressDetection= _disable_ IPv6 DAD if set to yes.
It is very confusing...

Author: yuwata

man/systemd.network.xml

@@ -984,18 +984,19 @@
           </listitem>
         </varlistentry>
         <varlistentry>
-          <term><varname>DuplicateAddressDetection=</varname></term>
+          <term><varname>IPv6DuplicateAddressDetection=</varname></term>
           <listitem>
-            <para>Takes a boolean. Do not perform Duplicate Address Detection
-            <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink> when adding this address.
-            Supported only on IPv6. Defaults to false.</para>
+            <para>Takes a boolean. When true performs IPv6 Duplicate Address Detection. See
+            <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink>.
+            Supported only on IPv6. Defaults to true.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><varname>IPv4DuplicateAddressDetection=</varname></term>
           <listitem>
             <para>Takes a boolean. When true performs IPv4 Duplicate Address Detection. See
-            <ulink url="https://tools.ietf.org/html/rfc5227">RFC 5224</ulink>. Defaults to false.</para>
+            <ulink url="https://tools.ietf.org/html/rfc5227">RFC 5224</ulink>.
+            Supported only on IPv4. Defaults to false.</para>
           </listitem>
         </varlistentry>
         <varlistentry>

src/network/networkd-address.c

@@ -32,6 +32,7 @@ int address_new(Address **ret) {
                 .scope = RT_SCOPE_UNIVERSE,
                 .cinfo.ifa_prefered = CACHE_INFO_INFINITY_LIFE_TIME,
                 .cinfo.ifa_valid = CACHE_INFO_INFINITY_LIFE_TIME,
+                .ipv6_duplicate_address_detection = true,
         };
 
         *ret = TAKE_PTR(address);
@@ -593,7 +594,7 @@ int address_configure(
         if (address->home_address)
                 address->flags |= IFA_F_HOMEADDRESS;
 
-        if (address->duplicate_address_detection)
+        if (!address->ipv6_duplicate_address_detection)
                 address->flags |= IFA_F_NODAD;
 
         if (address->manage_temporary_address)
@@ -994,14 +995,18 @@ int config_parse_address_flags(const char *unit,
         r = parse_boolean(rvalue);
         if (r < 0) {
                 log_syntax(unit, LOG_ERR, filename, line, r,
-                           "Failed to parse address flag, ignoring: %s", rvalue);
+                           "Failed to parse %s=, ignoring: %s", lvalue, rvalue);
                 return 0;
         }
 
         if (streq(lvalue, "HomeAddress"))
                 n->home_address = r;
         else if (streq(lvalue, "DuplicateAddressDetection"))
-                n->duplicate_address_detection = r;
+                n->ipv6_duplicate_address_detection = !!r;
+        else if (streq(lvalue, "IPv6DuplicateAddressDetection"))
+                n->ipv6_duplicate_address_detection = r;
+        else if (streq(lvalue, "IPv4DuplicateAddressDetection"))
+                n->ipv4_duplicate_address_detection = r;
         else if (streq(lvalue, "ManageTemporaryAddress"))
                 n->manage_temporary_address = r;
         else if (streq(lvalue, "PrefixRoute"))
@@ -1058,43 +1063,6 @@ int config_parse_address_scope(const char *unit,
         return 0;
 }
 
-int config_parse_address_ipv4_dad(const char *unit,
-                                  const char *filename,
-                                  unsigned line,
-                                  const char *section,
-                                  unsigned section_line,
-                                  const char *lvalue,
-                                  int ltype,
-                                  const char *rvalue,
-                                  void *data,
-                                  void *userdata) {
-        Network *network = userdata;
-        _cleanup_(address_free_or_set_invalidp) Address *n = NULL;
-        int r;
-
-        assert(filename);
-        assert(section);
-        assert(lvalue);
-        assert(rvalue);
-        assert(data);
-
-        r = address_new_static(network, filename, section_line, &n);
-        if (r < 0)
-                return r;
-
-        r = parse_boolean(rvalue);
-        if (r < 0) {
-                log_syntax(unit, LOG_ERR, filename, line, r,
-                           "Failed to parse IPv4 duplicate address detection, ignoring: %s", rvalue);
-                return 0;
-        }
-
-        n->ipv4_duplicate_address_detection = r;
-
-        n = NULL;
-        return 0;
-}
-
 bool address_is_ready(const Address *a) {
         assert(a);
 

src/network/networkd-address.h

@@ -40,7 +40,7 @@ struct Address {
         union in_addr_union in_addr_peer;
 
         bool ip_masquerade_done:1;
-        bool duplicate_address_detection:1;
+        bool ipv6_duplicate_address_detection:1;
         bool ipv4_duplicate_address_detection:1;
         bool manage_temporary_address:1;
         bool home_address:1;

src/network/networkd-network-gperf.gperf

@@ -105,11 +105,12 @@ Address.Broadcast,                      config_parse_broadcast,
 Address.Label,                          config_parse_label,                              0,                             0
 Address.PreferredLifetime,              config_parse_lifetime,                           0,                             0
 Address.HomeAddress,                    config_parse_address_flags,                      0,                             0
-Address.DuplicateAddressDetection,      config_parse_address_flags,                      0,                             0
+Address.DuplicateAddressDetection,      config_parse_address_flags,                      0,                             0 /* deprecated */
+Address.IPv6DuplicateAddressDetection,  config_parse_address_flags,                      0,                             0
+Address.IPv4DuplicateAddressDetection,  config_parse_address_flags,                      0,                             0
 Address.ManageTemporaryAddress,         config_parse_address_flags,                      0,                             0
 Address.PrefixRoute,                    config_parse_address_flags,                      0,                             0
 Address.AutoJoin,                       config_parse_address_flags,                      0,                             0
-Address.IPv4DuplicateAddressDetection,  config_parse_address_ipv4_dad,                   0,                             0
 Address.Scope,                          config_parse_address_scope,                      0,                             0
 IPv6AddressLabel.Prefix,                config_parse_address_label_prefix,               0,                             0
 IPv6AddressLabel.Label,                 config_parse_address_label,                      0,                             0

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

@@ -196,6 +196,8 @@ RestartSec=
 TripleSampling=
 [Address]
 DuplicateAddressDetection=
+IPv6DuplicateAddressDetection=
+IPv4DuplicateAddressDetection=
 AutoJoin=
 PreferredLifetime=
 Address=
@@ -206,7 +208,6 @@ ManageTemporaryAddress=
 Broadcast=
 Peer=
 Label=
-IPv4DuplicateAddressDetection=
 [RoutingPolicyRule]
 Table=
 IncomingInterface=