Fakernet - FPGA gateware for TCP/IP data source and UDP control

General Information

Fakernet is a fast FPGA-based TCP/IP data source with UDP control channels.
The FPGA board needs a PHY interface. No special kernel/OS drivers are needed.
The network connection to a controlling computer uses ordinary Ethernet equipment.
Typical use case: data acquisition.

Type
Special-purpose gateware and software.
Language
Gateware: VHDL. Helper library: C.
License
Fakernet is free software; distributed under the 3-clause BSD license.
See the accompanying LICENSE file.
Main developers
Håkan T. Johansson and Anders Furufors, Chalmers University of Technology, Sweden. Discussions: Philipp Klenze, Technische Universität München,
Distributor
Experimental subatomic physics group, Chalmers University of Technology, Sweden.
Acknowledgment
The research leading to these results was supported by the Swedish Research Council: the Scientific Council for Natural and Engineering Sciences under grant 2017-03839 and the Council for Research infrastructure under grant 822-2014-6644.
Reference
The recommended way to refer to Fakernet, when used for work that is published in a research article, is to cite the following paper:
H. T. Johansson, A. Furufors and P. Klenze, Fakernet - small and fast FPGA-based TCP and UDP communication. Pre-print (2020) at arXiv:2003.12527

Download

Location
http://fy.chalmers.se/~f96hajo/fakernet/fakernet-0.9.6.tar.gz
Contact
Håkan T. Johansson (f96hajo@chalmers.se)
Version
0.9.6 (CHANGELOG)
Support
No formal support.
Repository
https://gitlab.com/inkdot7/fakernet

Documentation

See README (included with download).

A short slide-show presentation.

Another short slide-show presentation.

Testing with a Arty A7-35 board.

NTP server with a Arty A7-35 board and GPS.

0.5 ns signal sampler with a Arty A7-35 board.

Direct LMD data generation for DAQ or analysis consumption.

Interfaces

FPGA module in VHDL
The Fakernet module receive and deliver packet data from and to the PHY.
The UDP control interface exposes a register read-write interface.
Data to be transmitted over TCP is committed to an internal buffer. 
entity fakernet_module is
  generic (-- Size of output (TCP) data buffer
           data_bufsize_addrbits : natural);
  port (clk            : in  std_logic;
        -- Config
        cfg_macaddr    : in  std_logic_vector (47 downto 0);
        cfg_ipaddr     : in  std_logic_vector (31 downto 0);
        -- Input network traffic
        in_word        : in  std_logic_vector(15 downto 0);
        in_got_word    : in  std_logic;
        in_new_packet  : in  std_logic;
        -- Output network traffic
        out_word       : out std_logic_vector(15 downto 0);
        out_ena        : out std_logic;
        out_payload    : out std_logic;
        out_taken      : in  std_logic;
        -- Register access interface (UDP access)
        reg_addr       : out std_logic_vector(24 downto 0);
        reg_data_wr    : out std_logic_vector(31 downto 0);
        reg_data_rd    : in  std_logic_vector(31 downto 0);
        reg_write      : out std_logic;
        reg_read       : out std_logic;
        reg_done       : in  std_logic;
        reg_cnt        : out std_logic_vector(3 downto 0);
        -- Data input interface (for TCP stream)
        data_word      : in  std_logic_vector(31 downto 0);
        data_offset    : in  std_logic_vector;
        data_write     : in  std_logic;
        data_commit_len: in  std_logic_vector;
        data_commit    : in  std_logic;
        data_free      : out std_logic;
        tcp_reset      : out std_logic;
        -- Signals to drive RTT estimate and timeouts
        slow_clock_tick     : in std_logic;
        timeout_tick        : in std_logic;
        );
end;
UDP communication functions in C
The most important functions, with their major arguments: 
/* Establish UDP connection. */
struct fnet_ctrl_client *
  fnet_ctrl_connect(const char *server,
                    int reliable);

/* Close connection. */
int
  fnet_ctrl_close(struct fnet_ctrl_client *client);

/* Retrieve pointers to prepare UDP register access. */
void
  fnet_ctrl_get_send_recv_bufs(struct fnet_ctrl_client *client,
                               fakernet_reg_acc_item **send,
                               fakernet_reg_acc_item **recv);

/* Perform UDP register access. */
int
  fnet_ctrl_send_recv_regacc(struct fnet_ctrl_client *client,
                             int num_items);

/* Reset TCP connection (done via UDP). */
int
  fnet_ctrl_reset_tcp(struct fnet_ctrl_client *client);
TCP stream reading
The data stream is read using normal read() calls, pseudo-code: 
fd = socket(TCP);
connect(fd, ip4_addr);
for ( ; ; )
 read(fd, buffer, n);
Comments? f96hajo@chalmers.se

Last modified: Sun Dec 18 23:25:18 CET 2022