Merge pull request #29910 from yuwata/rapid-commit

dhcp: about rapid commit

9 files changed, 52 insertions, 3 deletions

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 3e83caaf18..fe8c8a14c6 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -3768,6 +3768,18 @@ ServerAddress=192.168.0.1/24</programlisting>
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>RapidCommit=</varname></term>
+        <listitem>
+          <para>Takes a boolean. When true, the server supports
+          <ulink url="https://datatracker.ietf.org/doc/html/rfc4039">RFC 4039</ulink>. When a client sends
+          a DHCPDISCOVER message with the Rapid Commit option to the server, then the server will reply with
+          a DHCPACK message to the client, instead of DHCPOFFER. Defaults to true.</para>
+
+          <xi:include href="version-info.xml" xpointer="v255"/>
+        </listitem>
+      </varlistentry>
+
     </variablelist>
   </refsect1>
 
diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 1879b5b159..8db517293f 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -84,6 +84,7 @@ struct sd_dhcp_server {
         usec_t max_lease_time;
         usec_t default_lease_time;
         usec_t ipv6_only_preferred_usec;
+        bool rapid_commit;
 
         sd_dhcp_server_callback_t callback;
         void *callback_userdata;
@@ -108,6 +109,7 @@ typedef struct DHCPRequest {
         char *hostname;
         const uint8_t *parameter_request_list;
         size_t parameter_request_list_len;
+        bool rapid_commit;
 } DHCPRequest;
 
 extern const struct hash_ops dhcp_lease_hash_ops;
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 8a94685ba7..bbe0b5227b 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -1367,6 +1367,7 @@ static int client_timeout_resend(
                 } else if (client->attempt >= client->max_attempts)
                         goto error;
 
+                client->request_sent = time_now;
                 break;
 
         case DHCP_STATE_SELECTING:
@@ -1374,9 +1375,7 @@ static int client_timeout_resend(
                 if (r < 0 && client->attempt >= client->max_attempts)
                         goto error;
 
-                if (client->rapid_commit)
-                        client->request_sent = time_now;
-
+                client->request_sent = time_now;
                 break;
 
         case DHCP_STATE_INIT_REBOOT:
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 54a659766d..437028800d 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -211,6 +211,7 @@ int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) {
                 .bind_to_interface = true,
                 .default_lease_time = DHCP_DEFAULT_LEASE_TIME_USEC,
                 .max_lease_time = DHCP_MAX_LEASE_TIME_USEC,
+                .rapid_commit = true,
         };
 
         *ret = TAKE_PTR(server);
@@ -692,6 +693,15 @@ static int server_send_offer_or_ack(
                         return r;
         }
 
+        if (server->rapid_commit && req->rapid_commit && type == DHCP_ACK) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                SD_DHCP_OPTION_RAPID_COMMIT,
+                                0, NULL);
+                if (r < 0)
+                        return r;
+        }
+
         return dhcp_server_send_packet(server, req, packet, type, offset);
 }
 
@@ -810,6 +820,10 @@ static int parse_request(uint8_t code, uint8_t len, const void *option, void *us
                 req->parameter_request_list = option;
                 req->parameter_request_list_len = len;
                 break;
+
+        case SD_DHCP_OPTION_RAPID_COMMIT:
+                req->rapid_commit = true;
+                break;
         }
 
         return 0;
@@ -1210,6 +1224,9 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, siz
                         /* no free addresses left */
                         return 0;
 
+                if (server->rapid_commit && req->rapid_commit)
+                        return server_ack_request(server, req, existing_lease, address);
+
                 r = server_send_offer_or_ack(server, req, address, DHCP_OFFER);
                 if (r < 0)
                         /* this only fails on critical errors */
@@ -1274,6 +1291,9 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, siz
                         address = req->message->ciaddr;
                 }
 
+                /* Silently ignore Rapid Commit option in REQUEST message. */
+                req->rapid_commit = false;
+
                 /* disallow our own address */
                 if (address == server->address)
                         return 0;
@@ -1545,6 +1565,13 @@ int sd_dhcp_server_set_ipv6_only_preferred_usec(sd_dhcp_server *server, uint64_t
         return 0;
 }
 
+int sd_dhcp_server_set_rapid_commit(sd_dhcp_server *server, int enabled) {
+        assert_return(server, -EINVAL);
+
+        server->rapid_commit = enabled;
+        return 0;
+}
+
 int sd_dhcp_server_set_servers(
                 sd_dhcp_server *server,
                 sd_dhcp_lease_server_type_t what,
diff --git a/src/network/networkd-dhcp-server.c b/src/network/networkd-dhcp-server.c
index 17939ce54a..607fe0053c 100644
--- a/src/network/networkd-dhcp-server.c
+++ b/src/network/networkd-dhcp-server.c
@@ -418,6 +418,11 @@ static int dhcp4_server_configure(Link *link) {
         if (r < 0)
                 return log_link_warning_errno(link, r, "Failed to set boot filename for DHCPv4 server instance: %m");
 
+        r = sd_dhcp_server_set_rapid_commit(link->dhcp_server, link->network->dhcp_server_rapid_commit);
+        if (r < 0)
+                return log_link_warning_errno(link, r, "Failed to %s Rapid Commit support for DHCPv4 server instance: %m",
+                                              enable_disable(link->network->dhcp_server_rapid_commit));
+
         for (sd_dhcp_lease_server_type_t type = 0; type < _SD_DHCP_LEASE_SERVER_TYPE_MAX; type ++) {
 
                 if (!link->network->dhcp_server_emit[type].emit)
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 080f72dc2c..628b1ad19f 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -342,6 +342,7 @@ DHCPServer.BindToInterface,                  config_parse_bool,
 DHCPServer.BootServerAddress,                config_parse_in_addr_non_null,                            AF_INET,                       offsetof(Network, dhcp_server_boot_server_address)
 DHCPServer.BootServerName,                   config_parse_dns_name,                                    0,                             offsetof(Network, dhcp_server_boot_server_name)
 DHCPServer.BootFilename,                     config_parse_string,                                      CONFIG_PARSE_STRING_SAFE_AND_ASCII, offsetof(Network, dhcp_server_boot_filename)
+DHCPServer.RapidCommit,                      config_parse_bool,                                        0,                             offsetof(Network, dhcp_server_rapid_commit)
 DHCPServerStaticLease.Address,               config_parse_dhcp_static_lease_address,                   0,                             0
 DHCPServerStaticLease.MACAddress,            config_parse_dhcp_static_lease_hwaddr,                    0,                             0
 Bridge.Cost,                                 config_parse_uint32,                                      0,                             offsetof(Network, cost)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index fbda52f8f3..72ed2abd95 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -428,6 +428,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .dhcp_server_emit[SD_DHCP_LEASE_SIP].emit = true,
                 .dhcp_server_emit_router = true,
                 .dhcp_server_emit_timezone = true,
+                .dhcp_server_rapid_commit = true,
 
                 .router_lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
                 .router_dns_lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 021e7f9182..4995e55b53 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -228,6 +228,7 @@ struct Network {
         char *dhcp_server_boot_server_name;
         char *dhcp_server_boot_filename;
         usec_t dhcp_server_ipv6_only_preferred_usec;
+        bool dhcp_server_rapid_commit;
 
         /* link-local addressing support */
         AddressFamily link_local;
diff --git a/src/systemd/sd-dhcp-server.h b/src/systemd/sd-dhcp-server.h
index 1256076b83..feafa5d1fc 100644
--- a/src/systemd/sd-dhcp-server.h
+++ b/src/systemd/sd-dhcp-server.h
@@ -85,6 +85,7 @@ int sd_dhcp_server_set_static_lease(sd_dhcp_server *server, const struct in_addr
 int sd_dhcp_server_set_max_lease_time(sd_dhcp_server *server, uint64_t t);
 int sd_dhcp_server_set_default_lease_time(sd_dhcp_server *server, uint64_t t);
 int sd_dhcp_server_set_ipv6_only_preferred_usec(sd_dhcp_server *server, uint64_t t);
+int sd_dhcp_server_set_rapid_commit(sd_dhcp_server *server, int enabled);
 
 int sd_dhcp_server_forcerenew(sd_dhcp_server *server);