Fix packetcapture bpf filter issue (#6815)#6821
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In PacketCapture, packets which don’t match the target BPF can be received after the socket is created and before the bpf filter is applied.This patch use a zero bpf filter(match no packet), then empty out any packets that arrived before the “zero-BPF” filter was applied.At this point the socket is definitely empty and it can’t fill up with junk because the zero-BPF is in place. Then we replace the zero-BPF with the real BPF we want. Signed-off-by: Hang Yan <yhang@vmware.com> Co-authored-by: Antonin Bas <antonin.bas@broadcom.com>
antoninbas
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Nov 19, 2024
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/test-all |
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@antoninbas should we back port this to release 2.2? |
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@luolanzone yes I think we should backport this |
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Nov 21, 2024
In PacketCapture, packets which don’t match the target BPF can be received after the socket is created and before the bpf filter is applied. This patch uses a zero bpf filter (matches no packet), then empties out any packets that arrived before the "zero-BPF" filter was applied. At this point the socket is definitely empty and it can’t fill up with junk because the zero-BPF is in place. Then we replace the zero-BPF with the real BPF we want. Signed-off-by: Hang Yan <yhang@vmware.com> Co-authored-by: Antonin Bas <antonin.bas@broadcom.com>
hangyan
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In PacketCapture, packets which don’t match the target BPF can be received after the socket is created and before the bpf filter is applied. This patch uses a zero bpf filter (matches no packet), then empties out any packets that arrived before the "zero-BPF" filter was applied. At this point the socket is definitely empty and it can’t fill up with junk because the zero-BPF is in place. Then we replace the zero-BPF with the real BPF we want. Signed-off-by: Hang Yan <yhang@vmware.com> Co-authored-by: Antonin Bas <antonin.bas@broadcom.com>
antoninbas
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Feb 10, 2025
…6815) (#6821)#6804: Fix PacketCapture pcapng file issue on macOS (#6804) (#6983) * Fix packetcapture bpf filter issue (#6815) (#6821) In PacketCapture, packets which don’t match the target BPF can be received after the socket is created and before the bpf filter is applied. This patch uses a zero bpf filter (matches no packet), then empties out any packets that arrived before the "zero-BPF" filter was applied. At this point the socket is definitely empty and it can’t fill up with junk because the zero-BPF is in place. Then we replace the zero-BPF with the real BPF we want. Signed-off-by: Hang Yan <yhang@vmware.com> Co-authored-by: Antonin Bas <antonin.bas@broadcom.com> * Fix PacketCapture pcapng file issue on macOS (#6804) By default, gopacket will write snap length=0 in the pcapng file header, means unlimited snaplen. tcpdump on macOS (libpcap version 1.10.1) cannot recognize this and will report error. This patch sets a default value (65535) for it. For #6795 Signed-off-by: Hang Yan <yhang@vmware.com> --------- Signed-off-by: Hang Yan <yhang@vmware.com> Co-authored-by: Antonin Bas <antonin.bas@broadcom.com>
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In PacketCapture, packets which don’t match the target BPF can be received after the socket is created and before the bpf filter is applied.This patch use a zero bpf filter(match no packet), then empty out any packets that arrived before the “zero-BPF” filter was applied.At this point the socket is definitely empty and it can’t fill up with junk because the zero-BPF is in place. Then we replace the zero-BPF with the real BPF we want.