[lttng-dev] LTTng Support for Network Namespace

[lttng-dev] LTTng Support for Network Namespace

[Mohammad Kavousi via lttng-dev]

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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.

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 }


Thanks, we appreciate the help beforehand!


Mohammad

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Re: [lttng-dev] LTTng Support for Network Namespace

[Mathieu Desnoyers via lttng-dev]

----- On Feb 8, 2021, at 1:04 PM, lttng-dev lttng-dev@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

> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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