On Tue, 1/28/14, Pavel Emelyanov [off-list ref] wrote:

When *_diag module is missing in the kernel, the ss tool should go
ad read legacry /proc/* files.

This is the case when all *_diag stuff is missing, but in case the
inet_diag.ko is loaded, but (tcp|udp)_diag.ko is not, the ss tool
doesn't notice this and produces empty output. The reason for that
is -- error from the inet_diag module (which means, that e.g. the
udp_diag is missing) is reported in the NLMSG_DONE message body.

That said, we need to check the NLMSG_DONE's message return code
and act respectively.

Reported-by: François-Xavier Le Bail <redacted>
Signed-off-by: Pavel Emelyanov <redacted>

---

Tested-by: François-Xavier Le Bail <redacted>