Merge branch 'Add skb_adjust_room() for SK_SKB'

Merge branch 'Add skb_adjust_room() for SK_SKB'

John Fastabend says:

====================
This implements the helper skb_adjust_room() for BPF_SKS_SK_STREAM_VERDICT
programs so we can push/pop headers from the data on recieve. One use
case is to pop TLS headers off kTLS packets.

The first patch implements the helper and the second updates test_sockmap
to use it removing some case handling we had to do earlier to account for
the TLS headers in the kTLS tests.

v1->v2:
 Fix error path for TLS case (Daniel)
 check mode input is 0 because we don't use it now (Daniel)
 Remove incorrect/misleading comment (Lorenz)

Thanks,
John
Acked-by: Martin KaFai Lau <kafai@fb.com>
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====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>