bpf: Test with non-linear skb #14
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This bit of refactoring aims to simplify the next patch in this series, in which freeing 'data' is a bit less straightforward. Tested-by: [email protected] Signed-off-by: Paul Chaignon <[email protected]>
This patch reorders the initialization of bpf_prog_test_run_skb to simplify the subsequent patch. Program types are checked first, followed by the ctx init, and finally the data init. With the subsequent patch, program types and the ctx init provide information that is used in the data init. Thus, we need the data init to happen last. Signed-off-by: Paul Chaignon <[email protected]>
This patch adds support for crafting non-linear skbs in BPF test runs for tc programs, via a new flag BPF_F_TEST_SKB_NON_LINEAR. When this flag is set, the size of the linear area is given by ctx->data_end, with a minimum of ETH_HLEN always pulled in the linear area. This is particularly useful to test support for non-linear skbs in large codebases such as Cilium. We've had multiple bugs in the past few years where we were missing calls to bpf_skb_pull_data(). This support in BPF_PROG_TEST_RUN would allow us to automatically cover this case in our BPF tests. In addition to the selftests introduced later in the series, this patch was tested by setting BPF_F_TEST_SKB_NON_LINEAR for all tc selftests programs and checking test failures were expected. Tested-by: [email protected] Suggested-by: Daniel Borkmann <[email protected]> Signed-off-by: Paul Chaignon <[email protected]>
This patch adds support for a new tag __linear_size in the test loader, to specify the size of the linear area in case of non-linear skbs. If the tag is absent or null, a linear skb is crafted. Signed-off-by: Paul Chaignon <[email protected]>
This patch adds new selftests in the direct packet access suite, to cover the non-linear case with BPF_F_TEST_SKB_NON_LINEAR. The three first tests cover the behavior of the bounds check with a non-linear skb (first two with min. linear size, third with long enough linear size). The last test adds a call to bpf_skb_pull_data() to be able to access the packet. Signed-off-by: Paul Chaignon <[email protected]>
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Signed-off-by: Paul Chaignon <[email protected]>
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