Use of 'mtu' field in sk structure under 2.0.3x

Philip Gladstone (philip@raptor.com)
Mon, 01 Mar 1999 10:33:47 -0500


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I'm somewhat confused about the use of the mtu field in the sock
structure for TCP sockets under 2.0.36. Sometimes the code uses
sk->ip_route_cache->rt_mtu and sometimes it uses sk->mtu. The path
mtu discovery code tries to update both fields.

sk->mtu seems to be set at 576 -- and comments in the code indicate
that changing sk->mtu after the start of a connection is *bad news*.

Can anybody explain when one field rather than the other should be
used?

[The reason for my interest is that I have path mtu discovery problems
with sockets that are bound to a particular interface]

Philip

-- 
Philip Gladstone                           +1 781 530 2461
Axent Technologies, Waltham, MA
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