[lttng-dev] LTTng Support for Network Namespace

[Mathieu Desnoyers]

----- On Feb 8, 2021, at 1:04 PM, lttng-dev lttng-dev at lists.lttng.org wrote:

> Dear LTTng developers,
> I was wondering if LTTng currently (or in the future) supports network
> namespaces. For instance, an ambiguity in the logs would make problems for
> future system analysis.

Did you try the "net_ns" context ? 

> Taking the "bind" system call, that would help us distinguish between different
> local IP addresses when two or more container instances are running on the
> host, given that the "umyaddr" field is an address inside the memory, how would
> we recover the local addresses after the trace has been collected?

> syscall_entry_bind: { cpu_id = 1 }, { mnt_ns = 4026532553, pid = 532, tid = 532,
> vtid = 532, vpid = 532 }, { fd = 14, umyaddr = 93827759199256, addrlen = 12 }

In lttng-modules, we'd need to implement a system call override for the bind system
call which fetches the umyaddr content from user-space. You can see the x86-64 override
code for the "connect" system call which fetches the uservaddr from user-space as an
inspiration.

Thanks,

Mathieu


> Thanks, we appreciate the help beforehand!

> Mohammad

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-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com