>> Declare ip6_src and/or ip6->ip6_src as __attribute__((__packed__))
>> and gcc should stop assuming that they have the alignment their type
>> would normally call for, at least as I read extend.texi.
> struct ip6_hdr is in fact declared with __attribute__((__packed__)).
> Shouldn't it indicate that its members can be misaligned, too?

I don't think so.  Packed applied to a struct is different from packed
applied to a variable or a member of a struct, as I read extend.texi.

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