Ben Pfaff
89d08b1a17
Because of historical string munging during the kernel build process if you named your hardware table hwtable-something, when it was built the filename would look appropriate, but the actual module info would change the internal name to be hwtable_something, thus after an insmod with the filename you could not perform an rmmod with the same filename. As a result the naming scheme has been changed to hwtable_NAME, NAME being the hardware the table supports. Further, include files in the hardware table should be prefixed with the folder name, e.g. #include "hwtable_NAME/my_header.h". Based on commits from David Erickson <derickso@stanford.edu>.
39 lines
1.9 KiB
Plaintext
39 lines
1.9 KiB
Plaintext
Hardware Table Support -*- text -*-
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----------------------
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The OpenFlow reference implementation in this distribution provides a
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mechanism to support hardware that can accelerate OpenFlow switching.
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The mechanism consists of the ability to add a "hardware acceleration"
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switching table ahead of the software switching tables implemented by
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the reference implementation. The hardware switching table is
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expected to handle any incoming packets that it can on its own. Any
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packets that it cannot handle itself it may pass up to the software
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table implementations.
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Hardware table implementation are built as separate kernel modules
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that may be loaded after the openflow module. At most one hardware
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table module may be loaded at a time. Only datapaths created after a
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hardware table module is loaded (and before it is unloaded) will take
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advantage of hardware switching features.
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Creating a hardware table module is straightforward. Create a
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directory in the openflow source tree named datapath/hwtable_NAME,
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where NAME identifies the hardware that the module supports. Populate
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that directory with the C source files that comprise the module, plus
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a file named Modules.mk that specifies how to build the module. This
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distribution includes a "dummy" hardware module that demonstrates how
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this works.
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Even though only one may be loaded at a given time, any number of
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hardware table modules may be built along with the OpenFlow kernel
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modules. Specify each NAME that identifies a module to be built on
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the OpenFlow configure script command as the argument to
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--enable-hw-tables, e.g.:
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./configure --enable-hw-tables=NAME
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Each hardware table module's code is encapsulated in a directory, so
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it is easy to separate a hardware table implementation from OpenFlow.
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Simply package up the contents of the hwtable_NAME directory and
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distribute it for builders to extract into their distribution
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directory.
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