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Synergy Software Package User's Manual
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Synergy Software Package User's Manual
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The Dynamic Host Configuration Protocol (DHCP) is designed to completely automate DHCP Server allocation and dynamic IP address allocation through leasing an IP address to a client for a specified time.
In IPv6 networks, the DHCP protocol is of no use because it is limited to IPv4. Therefore, the DHCPv6 is the protocol used for dynamic global IPv6 address assignment from a DHCPv6 Server. This guide covers only the IPv4 version of DHCP, but applies to NetX™ and NetX™ Duo. A note will clearly identify where there are any differences in use between NetX and NetX Duo. To simplify wording in this document, NetX DHCPv4 will be used to stand for NetX and NetX Duo DHCP for IPv4.
The NetX DHCP Server defines APIs for creating, deleting, removing, starting, and stopping the server, for creating the pool of assignable IP addresses, and for setting up the network information for the client. A complete list of the available APIs, an example API call and a short description of each can be found in the following table. A table of status return values follows the API summary table.
NetX/NetX Duo DHCP Server Module API Summary
| Function Name | Example API Call and Description |
|---|---|
| nx_dhcp_server_create | nx_dhcp_server_create(&dhcp_server, &server_ip, pointer,DEMO_SERVER_STACK_SIZE, SERVER_IP_ADDRESS_LIST, "DHCP server", &server_pool);Create a DHCP Server instance. |
| nx_dhcp_create_server_ip_address_list | nx_dhcp_create_server_ip_list (&dhcp_server, iface_index,START_IP_ADDRESS_LIST, END_IP_ADDRESS_LIST, &addresses_added);Create pool of available IP addresses to assign to DHCP Clients on the specified network index. |
| nx_dhcp_clear_client_record | nx_dhcp_clear_client_record (&dhcp_server, &dhcp_client_ptr);Remove Client record in the Server database. |
| nx_dhcp_set_interface_network_parameters | nx_dhcp_set_interface_network_parameters(&dhcp_server, iface_index,NX_DHCP_SUBNET_MASK, NX_DHCP_DEFAULT_GATEWAY,NX_DHCP_DNS_SERVER);Set DHCP options for adding critical network parameters on specified interface in messages to Clients. |
| nx_dhcp_server_delete | nx_dhcp_server_delete(&dhcp_server);Delete a DHCP Server instance. |
| nx_dhcp_server_start | nx_dhcp_server_start(&dhcp_server);Start or resume DHCP Server processing. |
| nx_dhcp_server_stop | nx_dhcp_server_stop(&dhcp_server);Stop DHCP server processing. |
Status Return Values
| Name | Description |
|---|---|
| NX_SUCCESS | Successful DHCP call. |
| NX_PTR_ERROR* | Invalid pointer input. |
| NX_DHCP_PARAMETER_ERROR | Invalid non-pointer input. |
| NX_DHCP_INADEQUATE_PACKET_POOL_PAYLOAD | Packet payload too small error. |
| NX_DHCP_NO_SERVER_OPTION_LIST | Missing option list; cannot create Server. |
| NX_DHCP_SERVER_BAD_INTERFACE_INDEX | Index does not match addresses. |
| NX_DHCP_INVALID_IP_ADDRESS | Invalid IP address or network interface for creating Server address list. |
| NX_DHCP_INVALID_IP_ADDRESS_LIST | Illogical start/end IP addresses for Server list. |
| NX_DHCP_INVALID_NETWORK_PARAMETERS | Invalid network parameters for DHCP messages to Client. |
| NX_DHCP_SERVER_ALREADY_STARTED | The DHCP instance has already been started. |
| NX_DHCP_SERVER_NOT_STARTED | DHCP Server not started. |
| NX_CALLER_ERROR* | Invalid caller of service. |
The DHCP server utilizes the UDP protocol to receive DHCP Client requests and transmit responses. It handles all details of creating an IP instance, initializing the driver, creating the UDP socket, and binding to the well-known DHCP port 67 to receive client requests.
The DHCP Server is assigned a packet pool when it is created. It can share the packet pool used by the IP instance (the IP default packet pool) or the module can create a separate one for the server. The packet payload must be large enough to include DHCP data, IP and UDP headers, and the physical frame header. DHCP data size is set by the Size of the BOOT Buffer (bytes) property, which defaults to 548 bytes.
Before starting the DHCP Server, the application must create a pool of assignable IP addresses; it does so by calling the nx_dhcp_create_server_ip_address_listservice. This service takes as input a starting IP address and an ending IP address. The server verifies the addresses are local network addresses. The DHCP Server services are interface-specific, including creating the IP address list and setting network parameters. The assumed network interface the DHCP Server is running on is the primary interface (index is zero). It fills a table of IP addresses sequentially starting at the starting IP address. The addresses_added pointer input returns the number of addresses added, which is equal to or less than the size of this table. The IP address table size is defined by the Maximum size of an IP addresses list property, which defaults to 20. There is one such table for each network interface on which the DHCP Server is receiving DHCP Client requests.
The DHCP Server keeps a record of each client (or rather the client's DISCOVER request) in its client record table. The record lives for as long as the client keeps the assigned IP address. If the client fails to renew, or fails to respond to the DHCP protocol before reaching the bound (IP address assigned) state, the record is deleted. One table holds all client records from all network interfaces on which the server receives DHCP requests. The size of the table is set by the Size of client record table (units) property, which defaults to 50.
Once the DHCP Server is running and has created client records and assigned IP addresses, it periodically checks the time remaining on each of the client IP leases. The length of the IP lease is set in the Client IP address lease time (seconds) property. The default value of 0xFFFFFFFF is essentially a permanent lease. To assign leases of finite length, set the lease to a more standard time. An example lease time might be 10 days (0x0d5930 or 874,800 seconds). The interval on which the DHCP Server checks the time remaining on assigned IP leases is set to 1000 seconds*.* If a lease expires, the server simply removes the client record from the client record table, and returns that IP address back to the pool of assignable IP addresses. No message is sent to the client. The client should have initiated renew or rebind requests before its lease expired; or possibly the client has left the network.
The DHCP Server also keeps an inactivity timeout on each client session. When a client sends a packet, the inactivity timeout for that client is reset. The interval on which the DHCP Server checks the time remaining is the Fast‑periodic timer interval to check valid sessions (ticks), which defaults to 10 ticks*.* This session timeout is this value multiplied by the ratio of ticks per second to produce a session timeout of 10 seconds. If a client record session time out expires, that client's IP address is returned to the pool of assignable IP addresses and the client record is cleared. No message is sent to the client.
This section describes how to include either or both the NetX and NetX Duo DHCP Server module in an application using the SSP configurator.
To add the NetX/NetX Duo DHCP Server module to an application, simply add it to a thread using the stacks selection sequence given in the following table.
NetX/NetX Duo DHCP Server Module Selection Sequence
| Resource | ISDE Tab | Stacks Selection Sequence |
|---|---|---|
| g_dhcp_Server0NetXDHCPServer | Threads | New Stack> X-Ware> NetX> Protocols> NetXDHCPServer |
| g_dhcp_Server0NetX Duo DHCP IPv4Server | Threads | New Stack> X-Ware> NetX Duo> Protocols> NetX Duo DHCP IPv4Server |
When the NetX and/or NetX Duo DHCP Server module is added to the thread stack as shown in the following figure, the configurator automatically adds any needed lower‑level modules. Any modules needing additional configuration information have the box text highlighted in Red. Modules with a Gray band are individual modules that stand alone. Modules with a Blue band are shared or common; they need only be added once and can be used by multiple stacks. Modules with a Pink band can require the selection of lower-level modules; these are either optional or recommended. (This is indicated in the block with the inclusion of this text.) If the addition of lower-level modules is required, the module description include Add in the text. Clicking on any Pink banded modules brings up the New icon and displays possible choices.
In the stack above, the NetX Network Driver (or NetX Duo Network Driver in a NetX Duo stack) has not been populated yet. There are multiple possible selections for the Network Driver; they are not all provided so as not to needlessly complicate the figure and the following configuration tables. The available options depend on the MCU target, but some typical options include:
The NetX/NetX Duo DHCP Server module must be configured by the user for the desired operation. The SSP configuration window automatically identifies (by highlighting the block in red) any required configuration selections, such as interrupts or operating modes, which must be configured for lower-level modules for successful operation. Only properties that can be changed without causing conflicts are available for modification. Other properties are locked and not available for changes and are identified with a lock icon for the locked property in the Properties window in the ISDE. This approach simplifies the configuration process and makes it much less error-prone than previous manual approaches to configuration. The available configuration settings and defaults for all the user-accessible properties are given in the Properties tab within the SSP Configurator and are shown in the following tables for easy reference.
Configuration Settings for the NetX/NetX Duo DHCP Server Module
| ISDE Property | Value | Description |
|---|---|---|
| Internal thread priority | 1 | Internal thread priority selection. |
| Packet allocate timeout (seconds) | 2 | Packet allocate timeout selection. |
| Fast periodic timer interval to check valid sessions (ticks) | 10 | Fast periodic timer interval to check valid sessions selection. |
| DHCP Client Session timeout - multiple of Fast periodic interval (seconds) | 10 | DHCP Client session timeout selection. |
| Client IP address default lease time (seconds) | 0xFFFFFFFF | Client IP address lease time selection. |
| Slow periodic timer inverval to check IP lease expiration (seconds) | 1000 | Slow periodic timer inverval to check IP lease expiration selection. |
| Size of the array to contain options in client request (units) | 12 | Size of the array containing current requested options selection. |
| Server option list (optional - use space for separation | 1 3 6 | Module server option list selection. |
| Server option list size (optional) | 3 | Server option list size selection. |
| Size of the server host main buffer (bytes) | 32 | Size of the server host main buffer selection. |
| Size of the current client hostname buffer (byte) | 32 | Size of the current client hostname buffer selection. |
| Maximum size of an IP addresses list (units) | 20 | Maximum size of an IP addresses list selection. |
| Size of the client record table (units) | 50 | Size of the client record table selection. |
| Size of the BOOT buffer (bytes) | 548 | Size of the BOOT buffer selection. |
| Name | g_dhcp_server0 | Module name. |
| Internal thread stack size (bytes) | NetX Default: 2048 NetX Duo Default: 4096 | Internal thread stack size selection. |
| Name of generated initialization function | nx_dhcp_server_init0 | Name of generated initialization function selection. |
| Auto Initialization | Enable, Disable Default: Enable | Auto initialization selection. |
In some cases, settings other than the defaults for stack modules can be desirable. For example, it might be useful to select different Ethernet interface pins and resets. The configurable properties for the lower-level stack modules are given in the following sections for completeness and as a reference.
Only a small number of settings must be modified from the default for the IP layer and lower-level drivers as indicated via the red text in the thread stack block. Notice that some of the configuration properties must be set to a certain value for proper framework operation and are locked to prevent user modification. The following table identifies all the settings within the properties section for the module:
Configuration Settings for the NetX/NetX Duo IP Instance
| ISDE Property | Value | Description |
|---|---|---|
| Name | g_ip0 | Module name. |
| IPv4 Address (use commas for separation) | 0,0,0,0 | IPv4 Address selection. |
| Subnet Mask (use commas for separation) | 255,255,255,0 | Subnet Mask selection. |
| **IPv6 Global Address (use commas for separation) | 0x2001, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1 | IPv6 global address selection. |
| **IPv6 Link Local Address (use commas for separation, All zeros means use MAC address) | 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 | IPv6 link local address selection. |
| IP Helper Thread Stack Size (bytes) | 2048 | IP Helper Thread Stack Size (bytes) selection. |
| IP Helper Thread Priority | 3 | IP Helper Thread Priority selection. |
| ARP | Enable | ARP selection. |
| ARP Cache Size in Bytes | 512 | ARP Cache Size in Bytes selection. |
| Reverse ARP | Enable, Disable Default: Disable | Reverse ARP selection. |
| TCP | Enable, Disable Default: Enable | TCP selection. |
| UDP | Enable, Disable Default: Enable | UDP selection. |
| ICMP | Enable, Disable Default: Enable | ICMP selection. |
| IGMP | Enable, Disable Default: Enable | IGMP selection. |
| IP fragmentation | Enable, Disable Default: Disable | IP fragmentation selection. |
| Name of generated initialization function | ip_init0 | Name of generated initialization function selection. |
| Auto Initialization | Enable, Disable Default: Enable | Auto initialization selection. |
** Indicates properties that are only available in NetX Duo.
Configuration Settings for the NetX/NetX Duo DHCP Common Instance
| ISDE Property | Value | Description |
|---|---|---|
| Type of Service for UDP requests | Normal, Minimum delay, Maximum data, Maximum reliability, Minimum cost Default: Normal | Type of service UDP requests selection. |
| Fragmentation option | Don't fragment, Fragment okay Default: Don't fragment | Fragmentation option selection. |
| Time to live | 128 | Time to live selection. |
| Packet Queue depth | 5 | Packet queue depth selection. |
Configuration Settings for the NetX/NetX Duo Common Instance
| ISDE Property | Value | Description |
|---|---|---|
| Name of generated initialization function | nx_common_init0 | Name of generated initialization function selection. |
| Auto Initialization | Enable, Disable Default: Enable | Auto initialization selection. |
Configuration Settings for the NetX/NetX Duo Packet Pool Instance
| ISDE Property | Value | Description |
|---|---|---|
| Name | g_packet_pool0 | Module name. |
| Packet Size in Bytes | 640 | Packet size selection. |
| Number of Packets in Pool | 16 | Number of packets in pool selection. |
| Name of generated initialization function | packet_pool_init0 | Name of generated initialization function selection. |
| Auto Initialization | Enable, Disable Default: Enable | Auto initialization selection. |
The ETHERC peripheral module uses PCLKA as its clock source. The PCLKA frequency is set using the SSP configurator clock tab prior to a build, or by using the CGC interface at run-time.
The ETHERC peripheral module uses pins on the MCU device to communicate to external devices. I/O pins must be selected and configured by the external device as required. The following table illustrates the method for selecting the pins within the SSP configuration window and the subsequent table illustrates an example selection for the I2C pins.
Pin Selection for the ETHERC Module
| Resource | ISDE Tab | Pin selection Sequence |
|---|---|---|
| ETHERC | Pins | Select Peripherals> Connectivity:ETHERC> ETHERC1.RMII |
Pin Configuration Settings for the ETHERC1
| Property | Value | Description |
|---|---|---|
| Operation Mode | Disabled, Custom, RMII Default: Disabled | Select RMII as the Operation Mode for ETHERC1. |
| Pin Group Selection | Mixed, _A only Default: _A only | Pin group selection. |
| REF50CK | P701 | REF50CK pin. |
| TXD0 | P700 | TXD0 pin. |
| TXD1 | P406 | TXD1 pin. |
| TXD_EN | P405 | TXD_EN pin. |
| RXD0 | P702 | RXD0 pin. |
| RXD1 | P703 | RXD1 pin. |
| RX_ER | P704 | RX_ER pin. |
| CRS_DV | P705 | CRS_DV pin. |
| MDC | P403 | MDC pin. |
| MDIO | P404 | MDIO pin. |
The steps in using the NetX/NetX Duo DHCP Server module in a typical application are:
nx_dhcp_create_server_ip_address_list API.nx_dhcp_set_interface_network_parameters API.nx_dhcp_server_start API.The following figure illustrates common steps in a typical operational flow diagram:
