bpf: encap: send TO_OVERLAY trace before adding encapsulation #25828
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When used from TC context, ctx_set_encap_info() merely adds the tunnel metadata without touching the packet content. So the send_trace_notify() still describes the content of the inner packet. But when called from XDP context, the ctx_set_encap_info() invocation pushes the actual tunnel headers. So the send_trace_notify() will report the *outer* packet. Move the trace statement slightly up, so that it consistently describes the inner packet. Note that we now get a trace entry when the subsequent ctx_set_encap_info() fails - so we would need to match any resulting drop notification against the preceding TRACE_TO_OVERLAY. Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
julianwiedmann
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This addresses one of the follow-ons from #24422. |
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/test |
gentoo-root
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Jun 2, 2023
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When used from TC context, ctx_set_encap_info() merely adds the tunnel metadata without touching the packet content. So the send_trace_notify() still describes the content of the inner packet.
But when called from XDP context, the ctx_set_encap_info() invocation pushes the actual tunnel headers. So the send_trace_notify() will report the outer packet.
Move the trace statement slightly up, so that it consistently describes the inner packet. Note that we now get a trace entry when the subsequent ctx_set_encap_info() fails - so we would need to match any resulting drop notification against the preceding TRACE_TO_OVERLAY.