[v1.13] bpf: use skb->ifindex for FIB lookup in handle_*_from_lxc() #24195
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[ upstream commit db5211f ] [ Backporter's notes: introduce a `iif` parameter for redirect_direct_* ] L7 LB traffic is first redirected to envoy for load-balancing. The corresponding local packet by envoy is then sent back to handle_policy_egress() by the cilium_from_host program via tail-call. In a config with ENABLE_HOST_ROUTING and multiple devices, it then potentially requires a in-BPF FIB lookup. For this lookup, we currently use ctx->ingress_ifindex (aka skb->skb_iif). For the normal veth->veth transition, the skb->skb_iif would be set by the __netif_receive_skb() in process_backlog(). But for a local packet (as generated by envoy for L7 LB) skb->skb_iif is not set. Consequently such a FIB lookup for ctx->ingress_ifindex 0 will fail, and the packet gets dropped with DROP_NO_FIB. Use ctx->ifindex instead. This changes nothing for normal from-pod traffic, but allows L7 LB traffic to perform a FIB lookup. Note that for the L7 LB case, ctx->ifindex will point at cilium_host (rather than the pod's veth interface). Signed-off-by: Julian Wiedmann <jwi@isovalent.com>
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/test-backport-1.13 Job 'Cilium-PR-K8s-1.24-kernel-4.9' failed: Click to show.Test NameFailure OutputIf it is a flake and a GitHub issue doesn't already exist to track it, comment Job 'Cilium-PR-K8s-1.21-kernel-4.9' failed: Click to show.Test NameFailure OutputIf it is a flake and a GitHub issue doesn't already exist to track it, comment Job 'Cilium-PR-K8s-1.25-kernel-4.19' failed: Click to show.Test NameFailure OutputIf it is a flake and a GitHub issue doesn't already exist to track it, comment |
sayboras
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Mar 6, 2023
sayboras
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Mar 6, 2023
borkmann
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Mar 6, 2023
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/test-1.25-4.19 |
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I believe kernel-4.9 errors are no longer relevant for v1.13 -> ready for merge. |
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jrajahalme
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Mar 10, 2023
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