selftests/bpf: fix race in flow dissector tests

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Since the "last_dissection" map holds only the flow keys for the most
recent packet, there is a small race in the skb-less flow dissector
tests if a new packet comes between transmitting the test packet, and
reading its keys from the map. If this happens, the test packet keys
will be overwritten and the test will fail.

Changing the "last_dissection" map to a hash map, keyed on the
source/dest port pair resolves this issue. Additionally, let's clear the
last test results from the map between tests to prevent previous test
cases from interfering with the following test cases.

Fixes: 0905beec9f ("selftests/bpf: run flow dissector tests in skb-less mode")
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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This commit is contained in:

Petar Penkov 2019-08-12 16:30:39 -07:00 • committed by Daniel Borkmann

parent d66fa3c70e

commit 9840a4ffcf

2 changed files with 27 additions and 8 deletions

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22

tools/testing/selftests/bpf/prog_tests/flow_dissector.c

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13

tools/testing/selftests/bpf/progs/bpf_flow.c

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