RFC_864_pattern is not correct with xinetd TCP server

[jeromecoutant]

Description

I set up a local TCP server in order to execute netsocket tests.

I am using xinetd, and configured services as recommened:

discard stream tcp6 nowait root internal
discard dgram udp6 wait root internal
echo stream tcp6 nowait root internal
echo dgram udp6 wait root internal
chargen stream tcp6 nowait root internal
chargen dgram udp6 wait root internal
daytime stream tcp6 nowait root internal
time stream tcp6 nowait root internal

Then, there are some issues with the chargen service in TCPSOCKET_RECV_100K sub test:

mbed-os/TESTS/netsocket/tcp/tcpsocket_recv_100k.cpp

Line 58 in 443e37b

static void generate_RFC_864_pattern(size_t offset, uint8_t *buf, size_t len)

After several checks, it seems there are several misalignments with what inetd service is providing:

• Pattern starts with !, not space

• 2 characters are missing : ~ and space

• sometimes, 2 lines are repeated : (maybe every 94*74 characters)

!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefgh
"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghi
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefgh
"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghi

I think current xinetd code is wrong…
https://github.com/xinetd-org/xinetd/blob/e7c1ba41f4f86b436fb82b0d55cd5d387bd4ecc4/xinetd/builtins.c#L377

But mbed-os test has to be updated with the current situation...

Issue request type

[ ] Question
[x] Enhancement
[ ] Bug

[adbridge]

Internal Jira reference: https://jira.arm.com/browse/ONME-3733

[SeppoTakalo]

Fix has been submitted in #8645 so this can be closed.