network/radv: update comment

DHCPv6PrefixDelegation= is replaced with DHCPPrefixDelegation=.

man/systemd.network.xml

@@ -6243,22 +6243,22 @@ Name=enp1s0
 [Network]
 DHCP=ipv6
 
-# The below setting is optional, to also assign an address in the delegated prefix
-# to the upstream interface. If not necessary, then comment out the line below and
-# the [DHCPPrefixDelegation] section.
-DHCPPrefixDelegation=yes
+# The lines below are optional, to also assign an address in the delegated prefix
+# to the upstream interface. Uncomment the lines below if necessary.
+#[Network]
+#DHCPPrefixDelegation=yes
+#[DHCPPrefixDelegation]
+#UplinkInterface=:self
+#SubnetId=0
+#Announce=no
 
-# If the upstream network provides Router Advertisement with Managed bit set,
-# then comment out the line below and WithoutRA= setting in the [DHCPv6] section.
-IPv6AcceptRA=no
-
-[DHCPv6]
-WithoutRA=solicit
-
-[DHCPPrefixDelegation]
-UplinkInterface=:self
-SubnetId=0
-Announce=no</programlisting>
+# If the upstream network does not provides any Router Advertisement (RA) messages
+# or provides an RA with both Managed and Other-information bits unset, then
+# uncomment the lines below.
+#[Network]
+#IPv6AcceptRA=no
+#[DHCPv6]
+#WithoutRA=solicit</programlisting>
 
       <programlisting># /etc/systemd/network/55-dhcpv6-pd-downstream.network
 [Match]

src/libsystemd-network/sd-dhcp6-client.c

@@ -767,6 +767,14 @@ int dhcp6_client_send_message(sd_dhcp6_client *client) {
 
         switch (client->state) {
         case DHCP6_STATE_INFORMATION_REQUEST:
+                /* RFC 7084 section 4.2 (https://datatracker.ietf.org/doc/html/rfc7084#section-4.2)
+                 * WPD-4: By default, the IPv6 CE router MUST initiate DHCPv6 prefix delegation when either
+                 * the M or O flags are set to 1 in a received Router Advertisement (RA) message. */
+                if (FLAGS_SET(client->request_ia, DHCP6_REQUEST_IA_PD)) {
+                        r = dhcp6_option_append_ia(&buf, &offset, (client->lease ? client->lease->ia_pd : NULL) ?: &client->ia_pd);
+                        if (r < 0)
+                                return r;
+                }
                 break;
 
         case DHCP6_STATE_SOLICITATION:

src/libsystemd-network/sd-dhcp6-lease.c

@@ -71,6 +71,32 @@ static void dhcp6_lease_set_lifetime(sd_dhcp6_lease *lease) {
         lease->lifetime_t2 = t2;
 }
 
+static void dhcp6_client_set_information_refresh_time(sd_dhcp6_client *client, sd_dhcp6_lease *lease, usec_t irt) {
+        usec_t t1 = USEC_INFINITY, t2 = USEC_INFINITY, min_valid_lt = USEC_INFINITY;
+
+        if (lease->ia_pd) {
+                t1 = be32_sec_to_usec(lease->ia_pd->header.lifetime_t1, /* max_as_infinity = */ true);
+                t2 = be32_sec_to_usec(lease->ia_pd->header.lifetime_t2, /* max_as_infinity = */ true);
+
+                LIST_FOREACH(addresses, a, lease->ia_pd->addresses)
+                        min_valid_lt = MIN(min_valid_lt, be32_sec_to_usec(a->iapdprefix.lifetime_valid, /* max_as_infinity = */ true));
+
+                if (t2 == 0 || t2 > min_valid_lt) {
+                        /* If T2 is zero or longer than the minimum valid lifetime of the prefixes,
+                         * then adjust lifetime with it. */
+                        t1 = min_valid_lt / 2;
+                        t2 = min_valid_lt / 10 * 8;
+                }
+
+                /* Adjust the received information refresh time with T1. */
+                irt = MIN(irt, t1);
+        }
+
+        client->information_refresh_time_usec = MAX(irt, IRT_MINIMUM);
+        log_dhcp6_client(client, "New information request will be refused in %s.",
+                         FORMAT_TIMESPAN(client->information_refresh_time_usec, USEC_PER_SEC));
+}
+
 #define DEFINE_GET_TIME_FUNCTIONS(name, val)                            \
         int sd_dhcp6_lease_get_##name(                                  \
                         sd_dhcp6_lease *lease,                          \
@@ -763,18 +789,12 @@ static int dhcp6_lease_parse_message(
                                 continue;
                         }
 
-                        dhcp6_ia_free(lease->ia_na);
-                        lease->ia_na = TAKE_PTR(ia);
+                        free_and_replace_full(lease->ia_na, ia, dhcp6_ia_free);
                         break;
                 }
                 case SD_DHCP6_OPTION_IA_PD: {
                         _cleanup_(dhcp6_ia_freep) DHCP6IA *ia = NULL;
 
-                        if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
-                                log_dhcp6_client(client, "Ignoring IA PD option in information requesting mode.");
-                                break;
-                        }
-
                         r = dhcp6_option_parse_ia(client, client->ia_pd.header.id, optcode, optlen, optval, &ia);
                         if (r == -ENOMEM)
                                 return log_oom_debug();
@@ -788,8 +808,7 @@ static int dhcp6_lease_parse_message(
                                 continue;
                         }
 
-                        dhcp6_ia_free(lease->ia_pd);
-                        lease->ia_pd = TAKE_PTR(ia);
+                        free_and_replace_full(lease->ia_pd, ia, dhcp6_ia_free);
                         break;
                 }
                 case SD_DHCP6_OPTION_RAPID_COMMIT:
@@ -872,12 +891,9 @@ static int dhcp6_lease_parse_message(
                                               "The client ID in %s message does not match. Ignoring.",
                                               dhcp6_message_type_to_string(message->type));
 
-        if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
-                client->information_refresh_time_usec = MAX(irt, IRT_MINIMUM);
-                log_dhcp6_client(client, "New information request will be refused in %s.",
-                                 FORMAT_TIMESPAN(client->information_refresh_time_usec, USEC_PER_SEC));
-
-        } else {
+        if (client->state == DHCP6_STATE_INFORMATION_REQUEST)
+                dhcp6_client_set_information_refresh_time(client, lease, irt);
+        else {
                 r = dhcp6_lease_get_serverid(lease, NULL, NULL);
                 if (r < 0)
                         return log_dhcp6_client_errno(client, r, "%s has no server id",

src/libsystemd-network/test-dhcp6-client.c

@@ -493,6 +493,11 @@ static const uint8_t msg_information_request[] = {
         DHCP6_MESSAGE_INFORMATION_REQUEST,
         /* Transaction ID */
         0x0f, 0xb4, 0xe5,
+        /* IA_PD */
+        0x00, SD_DHCP6_OPTION_IA_PD, 0x00, 0x0c,
+        IA_ID_BYTES,
+        0x00, 0x00, 0x00, 0x00, /* lifetime T1 */
+        0x00, 0x00, 0x00, 0x00, /* lifetime T2 */
         /* MUD URL */
         /* ORO */
         0x00, SD_DHCP6_OPTION_ORO, 0x00, 0x0c,

src/network/networkd-dhcp6.c

@@ -264,30 +264,40 @@ static int dhcp6_address_acquired(Link *link) {
                         return r;
         }
 
-        if (link->network->dhcp6_use_hostname) {
-                const char *dhcpname = NULL;
+        return 0;
+}
+
+static int dhcp6_request_hostname(Link *link) {
         _cleanup_free_ char *hostname = NULL;
+        const char *dhcpname = NULL;
+        int r;
 
-                (void) sd_dhcp6_lease_get_fqdn(link->dhcp6_lease, &dhcpname);
+        assert(link);
+        assert(link->network);
+
+        if (!link->network->dhcp6_use_hostname)
+                return 0;
+
+        r = sd_dhcp6_lease_get_fqdn(link->dhcp6_lease, &dhcpname);
+        if (r == -ENODATA)
+                return 0;
+        if (r < 0)
+                return r;
 
-                if (dhcpname) {
         r = shorten_overlong(dhcpname, &hostname);
         if (r < 0)
-                                log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s', ignoring: %m", dhcpname);
+                return log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s': %m", dhcpname);
         if (r == 1)
                 log_link_notice(link, "Overlong DHCP hostname received, shortened from '%s' to '%s'", dhcpname, hostname);
-                }
-                if (hostname) {
+
         r = manager_set_hostname(link->manager, hostname);
         if (r < 0)
-                                log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
-                }
-        }
+                log_link_warning_errno(link, r, "Failed to set transient hostname to '%s', ignoring: %m", hostname);
 
         return 0;
 }
 
-static int dhcp6_lease_ip_acquired(sd_dhcp6_client *client, Link *link) {
+static int dhcp6_lease_acquired(sd_dhcp6_client *client, Link *link) {
         _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease_old = NULL;
         sd_dhcp6_lease *lease;
         int r;
@@ -302,6 +312,10 @@ static int dhcp6_lease_ip_acquired(sd_dhcp6_client *client, Link *link) {
         lease_old = TAKE_PTR(link->dhcp6_lease);
         link->dhcp6_lease = sd_dhcp6_lease_ref(lease);
 
+        r = dhcp6_request_hostname(link);
+        if (r < 0)
+                return r;
+
         r = dhcp6_address_acquired(link);
         if (r < 0)
                 return r;
@@ -327,22 +341,6 @@ static int dhcp6_lease_ip_acquired(sd_dhcp6_client *client, Link *link) {
                 link_set_state(link, LINK_STATE_CONFIGURING);
 
         link_check_ready(link);
-        return 0;
-}
-
-static int dhcp6_lease_information_acquired(sd_dhcp6_client *client, Link *link) {
-        sd_dhcp6_lease *lease;
-        int r;
-
-        assert(client);
-        assert(link);
-
-        r = sd_dhcp6_client_get_lease(client, &lease);
-        if (r < 0)
-                return log_link_error_errno(link, r, "Failed to get DHCPv6 lease: %m");
-
-        unref_and_replace_full(link->dhcp6_lease, lease, sd_dhcp6_lease_ref, sd_dhcp6_lease_unref);
-
         link_dirty(link);
         return 0;
 }
@@ -387,11 +385,8 @@ static void dhcp6_handler(sd_dhcp6_client *client, int event, void *userdata) {
                 break;
 
         case SD_DHCP6_CLIENT_EVENT_IP_ACQUIRE:
-                r = dhcp6_lease_ip_acquired(client, link);
-                break;
-
         case SD_DHCP6_CLIENT_EVENT_INFORMATION_REQUEST:
-                r = dhcp6_lease_information_acquired(client, link);
+                r = dhcp6_lease_acquired(client, link);
                 break;
 
         default:

src/network/networkd-radv.c

@@ -1439,7 +1439,7 @@ int config_parse_router_prefix_delegation(
                 }
 
                 /* When IPv6SendRA= is enabled, only static prefixes are sent by default, and users
-                 * need to explicitly enable DHCPv6PrefixDelegation=. */
+                 * need to explicitly enable DHCPPrefixDelegation=. */
                 *ra = r ? RADV_PREFIX_DELEGATION_STATIC : RADV_PREFIX_DELEGATION_NONE;
                 return 0;
         }