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* sys: general adoption of SPDX licensing ID tags.Pedro F. Giffuni2017-11-271-0/+2
| | | | | | | | | | | | | | | | | Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended. Notes: svn path=/head/; revision=326272
* - Fix trivial typoEitan Adler2012-01-141-1/+1
| | | | | | | | Approved by: nwhitehorn MFC after: 3 days Notes: svn path=/head/; revision=230108
* Make sure we are clearing the ZBUF_FLAG_IMMUTABLE any time a free bufferChristian S.J. Peron2008-07-051-0/+1
| | | | | | | | | | | is reclaimed by the kernel. This fixes a bug resulted in the kernel over writing packet data while user-space was still processing it when zerocopy is enabled. (Or a panic if invariants was enabled). Discussed with: rwatson Notes: svn path=/head/; revision=180310
* Maintain and observe a ZBUF_FLAG_IMMUTABLE flag on zero-copy BPFRobert Watson2008-04-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | buffer kernel descriptors, which is used to allow the buffer currently in the BPF "store" position to be assigned to userspace when it fills, even if userspace hasn't acknowledged the buffer in the "hold" position yet. To implement this, notify the buffer model when a buffer becomes full, and check that the store buffer is writable, not just for it being full, before trying to append new packet data. Shared memory buffers will be assigned to userspace at most once per fill, be it in the store or in the hold position. This removes the restriction that at most one shared memory can by owned by userspace, reducing the chances that userspace will need to call select() after acknowledging one buffer in order to wait for the next buffer when under high load. This more fully realizes the goal of zero system calls in order to process a high-speed packet stream from BPF. Update bpf.4 to reflect that both buffers may be owned by userspace at once; caution against assuming this. Notes: svn path=/head/; revision=177966
* Introduce support for zero-copy BPF buffering, which reduces theChristian S.J. Peron2008-03-241-0/+53
overhead of packet capture by allowing a user process to directly "loan" buffer memory to the kernel rather than using read(2) to explicitly copy data from kernel address space. The user process will issue new BPF ioctls to set the shared memory buffer mode and provide pointers to buffers and their size. The kernel then wires and maps the pages into kernel address space using sf_buf(9), which on supporting architectures will use the direct map region. The current "buffered" access mode remains the default, and support for zero-copy buffers must, for the time being, be explicitly enabled using a sysctl for the kernel to accept requests to use it. The kernel and user process synchronize use of the buffers with atomic operations, avoiding the need for system calls under load; the user process may use select()/poll()/kqueue() to manage blocking while waiting for network data if the user process is able to consume data faster than the kernel generates it. Patchs to libpcap are available to allow libpcap applications to transparently take advantage of this support. Detailed information on the new API may be found in bpf(4), including specific atomic operations and memory barriers required to synchronize buffer use safely. These changes modify the base BPF implementation to (roughly) abstrac the current buffer model, allowing the new shared memory model to be added, and add new monitoring statistics for netstat to print. The implementation, with the exception of some monitoring hanges that break the netstat monitoring ABI for BPF, will be MFC'd. Zerocopy bpf buffers are still considered experimental are disabled by default. To experiment with this new facility, adjust the net.bpf.zerocopy_enable sysctl variable to 1. Changes to libpcap will be made available as a patch for the time being, and further refinements to the implementation are expected. Sponsored by: Seccuris Inc. In collaboration with: rwatson Tested by: pwood, gallatin MFC after: 4 months [1] [1] Certain portions will probably not be MFCed, specifically things that can break the monitoring ABI. Notes: svn path=/head/; revision=177548