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TCP/IP library

License: Other

Makefile 0.63% C 95.25% XC 2.96% C++ 0.26% Python 0.89%

lib_xtcp's Introduction

TCP/IP Library

Overview

A library providing two alternative TCP/UDP/IP protocol stacks for XMOS devices. This library connects to the XMOS Ethernet library to provide layer-3 traffic over Ethernet via MII or RGMII.

Features

TCP and UDP connection handling

DHCP, IP4LL, ICMP, IGMP support

Low level, event based interface for efficient memory usage

Supports IPv4 only, not IPv6

Stacks

This library provides two different TCP/IP stack implementations ported to the xCORE architecture.

uIP stack

The first stack ported is the uIP (micro IP) stack. The uIP stack has been designed to have a minimal resource footprint. As a result, it has limited performance and does not provide support for TCP windowing.

lwIP stack

The second stack ported is the lwIP (lightweight IP) stack. The lwIP stack requires more resources than uIP, but is designed to provide better throughput and also has support for TCP windowing.

Typical Resource Usage

.. resusage::

  * - configuration: UIP
    - globals: xtcp_ipconfig_t ipconfig = {
               { 0, 0, 0, 0 },
               { 0, 0, 0, 0 },
               { 0, 0, 0, 0 }
               };
               char mac_addr[6] = {0};
    - locals: interface mii_if i_mii; xtcp_if i_xtcp[1];
    - fn: xtcp_uip(i_xtcp, 1, i_mii,
                   null, null, null,
                   null, 0, mac_addr, null, ipconfig);
    - pins: 0
    - ports: 0
  * - configuration: LWIP
    - globals: xtcp_ipconfig_t ipconfig = {
               { 0, 0, 0, 0 },
               { 0, 0, 0, 0 },
               { 0, 0, 0, 0 }
               };
               char mac_addr[6] = {0};
    - locals: interface mii_if i_mii; xtcp_if i_xtcp[1];
    - fn: xtcp_lwip(i_xtcp, 1, i_mii,
                   null, null, null,
                   null, 0, mac_addr, null, ipconfig);
    - pins: 0
    - ports: 0
    - target: XCORE-200-EXPLORER

Software version and dependencies

.. libdeps::

Related application notes

The following application notes use this library:

AN00121 - Using the XMOS TCP/IP library

lib_xtcp's People

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ajwlucas samchesney ccrome brennangit jh14778 pthedinger fjes mohalgoblan xmos-jmccarthy ghsecuritylab cosmiccrouton pgbross arneg

lib_xtcp's Issues

static IP on slicekit GP XL216

Hi,

somehow I can't set static IP in the application. I have tried the same code with the latest released version 4.0.2 and app works fine.

I don't know what else should I change so that app uses static IP ?
Application passes to to uip.c file static IP address set in the main file.
Since there's no dhcp server on the network, it always gets the local IP 169/254.

Thank you

Sascha

lib_random

As both lib_xtcp and lib_crypto need access to a random number generator, it could be useful to export that functionality to a separate library (possible lib_random).

At the moment lib_xtcp has a copy of random.h and random.xc in its directory (under lib_xtcp/xtcp_lwip/xcore).

Library incorrectly pads small packets

In xcoredev.xc, lines 100-103 it incorrectly uses 64 bytes as the minimum packet size and pads:

    if (len < 64)  {
      for (int i=len;i<64;i++)
        (uip_buf32, unsigned char[])[i] = 0;
      len=64;
    }

This should be 60, as the CRC will be automatically added to make the size up to the minimum frame size of 64 bytes.

AN00121_udp_demo should be updated to the xCORE-200 sliceKIT

Currently it targets the L-16 sliceKIT.

Updating to support the xCORE-200 sliceKIT should add support for the RGMII based gigabit ethernet slice supplied in the kit.

mdns.h includes xtcp_client.h not xtcp.h

As in the title, this raises a warning in xtcp_client.h

xtcp polling performance

Hi there,
with the latest and greatest code, we get okay performance with lib_xtcp. However, the throughput leaves a bit to be desired.

I believe this is in part due to the length of the polling loop in xtcp(). Clearly, it's greatly improved from the previous revision, which is good, but it could still use a little help.

To that end, added a timer in the polling loop to see where the time is spent, and the results are:

Op	Time for this op (uS)	Cumulative time (uS)
xtcp_service_clients	.75	.75
xtcp_check_connection_poll	3.96	4.71
uip_xtcp_checkstate	.35	5.06
xtcp_process_udp_acks	.81	5.87
start of next loop (i.e. time to drop through the select statement)	.26	6.13

At 100MBit, an average packet of 1000 byts takes 80 uS on the wire. with a polling interval of 6 uS, this is maybe not a terrible ratio.

However, at 1000MBit, that same packet takes only 8uS, in which case the library when under load is spending a significant amount of time in xtcp_check_connection_poll.

Obviously, for smaller packets, the problem is much worse. (i.e. a 100 byte packet is only 0.8uS on the wire whereas the polling interval could be 10 times longer!)

Is there anything that can be done to improve performance here? It would be great if we could make this thing event driven rather than polled.

BTW, I checked this both when idle, and when the ethernet is under load at with ping -f and the timings are very consistent.

ipconfig may not be word aligned

xC compiler doesn't word align local arrays on the stack at the moment. While this may or may not change in the future, uip_server_init is casting char[4] in ipconfig that's passed to int*, which is not very good code. Suggest using memcmp or a for loop.

if (ipconfig != NULL && (*((int*)ipconfig->ipaddr) != 0)) {