UDP protocol fails totally

[bmah888]

From tru64.freak on December 09, 2010 08:04:11

What steps will reproduce the problem? 1. iperf3 -s
2. iperf3 -c server -u 3. What is the expected output? What do you see instead? no idea what to expect. What I get is:
client:
Connecting to host server, port 5201
error: Unable to read from stream socket: Connection refused

server:

Server listening on 5201

Accepted connection from 10.1.1.2, port 1840
Teh client has unexpectedly close the connection.
--------------- What version of the product are you using? On what operating system? iperf verion 3.0-BETA4 (2 Aug 2010)
OS: Tru64 v5.1 Please provide any additional information below. it is very disappointing that UDP does not work. As UDP is unreliable, and there is no compensation for packet loss/corruption as compared to TCP, it can be extremely useful in diagnosing connections that have problems.
It's a shame you haven't fixed this bug already.

Original issue: http://code.google.com/p/iperf/issues/detail?id=36

[bmah888]

From jdugan.esnet on December 15, 2010 11:31:10

UDP support is planned but is not yet finished. Patches are always welcome. "Talk is cheap. Show me the code." -- Linus Torvalds

[bmah888]

From kridgway@harris.com on June 22, 2011 01:28:18

UDP does not work because the -u parameter is not transferred correctly from the client to the server. The problem is with the use of getopt in iperf_api.c where the first parameter in params[0] is assumed to be the application name as it would be in agrv[]. The fix is to modify the loop on lines 623-630 as follows:

for (param = strtok(pstring, " "), n = 1, params = NULL; param; param = strtok(NULL, " ")) {
    if ((params = realloc(params, (n+1)*sizeof(char *))) == NULL) {
        i_errno = IERECVPARAMS;
        return (-1);
    }
    params[n] = param;
    n++;
}
params[0] = "";

[bmah888]

From andre.gomes.pt on July 04, 2011 17:31:31

For UDP testing, the server must also be initialized with -u option. So:

server> iperf -s -u
client> iperf -c -u

This works one time only. Issue 41 describes the problem. Hope this helps.

[bmah888]

From milutz on February 08, 2012 16:29:34

Re: comment 3

The referenced change is lines 623-630 as of r318 in the iperf_api.c file in the repo, but if your looking at the beta4 release its lines 590-597

If you don't have a diff tool handy, the changes are changing 'n=1' (not 0) in the first line and adding the 'params[0] = "";' after the block.

I can also confirm that this change (in my case solely made on the server side to the beta4 release) makes UDP mode work repeatedly, and without requiring specifying the "-u" when the server is run - its a surprisingly simple and potent fix!

[bmah888]

From jef.poskanzer on November 24, 2012 12:19:16

This one is fixed by the new JSON-based parameter transfer.

Status: Fixed