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* Run sphinxcontrib-spelling over docs * Correct spelling errors * Compile a dictionary for future spellchecking efforts Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
43 lines
1.9 KiB
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43 lines
1.9 KiB
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.. _kernel-interface:
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****************
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Kernel Interface
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****************
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There are several different methods for reading kernel routing table
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information, updating kernel routing tables, and for looking up interfaces.
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- ioctl
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This method is a very traditional way for reading or writing kernel
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information. `ioctl` can be used for looking up interfaces and for
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modifying interface addresses, flags, mtu settings and other types of
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information. Also, `ioctl` can insert and delete kernel routing table
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entries. It will soon be available on almost any platform which zebra
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supports, but it is a little bit ugly thus far, so if a better method is
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supported by the kernel, zebra will use that.
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- sysctl
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This is a program that can lookup kernel information using MIB (Management
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Information Base) syntax. Normally, it only provides a way of getting
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information from the kernel. So one would usually want to change kernel
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information using another method such as `ioctl`.
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- proc filesystem
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This is a special filesystem mount that provides an easy way of getting
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kernel information.
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- routing socket / Netlink
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On recent Linux kernels (2.0.x and 2.2.x), there is a kernel/user
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communication support called `Netlink`. It makes asynchronous communication
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between kernel and FRR possible, similar to a routing socket on BSD systems.
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Before you use this feature, be sure to select (in kernel configuration) the
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kernel/Netlink support option 'Kernel/User network link driver' and 'Routing
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messages'.
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Today, the :file:`/dev/route` special device file is obsolete. Netlink
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communication is done by reading/writing over Netlink socket.
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After the kernel configuration, please reconfigure and rebuild FRR. You can
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use Netlink as a dynamic routing update channel between FRR and the kernel.
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