bpf: netdev TX metadata #5207
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bpf: netdev TX metadata #5207
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No functional changes. To make existing dev-bound infrastructure more generic and be less tightly bound to the xdp layer, rename some functions and move kfunc-related things into kernel/bpf/offload.c Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
It is impossible to use skb_frag_t in the tracing program. So let's resolve a single typedef when walking the struct. Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
devtx is a lightweight set of hooks before and after packet transmission. The hook is supposed to work for both skb and xdp paths by exposing a light-weight packet wrapper via devtx_frame (header portion + frags). devtx is implemented as a tracing program which has access to the XDP-metadata-like kfuncs. The initial set of kfuncs is implemented in the next patch, but the idea is similar to XDP metadata: the kfuncs have netdev-specific implementation, but common interface. Upon loading, the kfuncs are resolved to direct calls against per-netdev implementation. This can be achieved by marking devtx-tracing programs as dev-bound (largely reusing xdp-dev-bound program infrastructure). Attachment and detachment is implemented via syscall BPF program by calling bpf_devtx_sb_attach (attach to tx-submission) or bpf_devtx_cp_attach (attach to tx completion). Right now, the attachment does not return a link and doesn't support multiple programs. I plan to switch to Daniel's bpf_mprog infra once it's available. Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
Two kfuncs, one per hook point: 1. at submit time - bpf_devtx_sb_request_timestamp - to request HW to put TX timestamp into TX completion descriptors 2. at completion time - bpf_devtx_cp_timestamp - to read out TX timestamp Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
Have a software-base example for kfuncs to showcase how it can be used in the real devices and to have something to test against in the selftests. Both path (skb & xdp) are covered. Only the skb path is really tested though. Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
Attach kfuncs that request and report TX timestamp via ringbuf. Confirm on the userspace side that the program has triggered and the timestamp is non-zero. Also make sure devtx_frame has a sensible pointers and data. Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
When we get packets on port 9091, we swap src/dst and send it out. At this point, we also request the timestamp and plumb it back to the userspace. The userspace simply prints the timestamp. Haven't really tested, still working on mlx5 patches... Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com>
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Upstream branch: ba49f97 |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=756388 expired. Closing PR. |
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Pull request for series with
subject: bpf: netdev TX metadata
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=756388