Date: Wed, 14 Feb 2007 18:05:15 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-net@FreeBSD.org Subject: [PATCH] BPF to support directions and more Message-ID: <200702141805.20228.jkim@FreeBSD.org>
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I was playing with some BPF ideas for few days and I added two new features. SEESENT flag is extended to see only outgoing packets, which is analogous to libpcap's PCAP_D_OUT direction. Thus SEESENT is now called DIRECTION. Second feature is feedback mode (sort of simulated hardware loopback), i.e., when packets are injected, you can feed them back as if they are coming from the wire. You can debug link layer protocols easily with this without second machine, network controller, or loopback plug. It's only tested with Ethernet, though. All necessary patches (including libpcap modification) are here: http://people.freebsd.org/~jkim/bpf_feedback.diff Don't forget to turn off all hardware assisted features (e.g., RX/TX checksum offloading) to test feedback mode. Otherwise, packets will be dropped. Jung-uk Kim Note: Actually I started this for QEMU networking, so that's another example. See: http://docs.freebsd.org/cgi/mid.cgi?200702092002.31220.jkim
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