34. Extending the DPDK

This chapter describes how a developer can extend the DPDK to provide a new library, a new target, or support a new target.

34.1. Example: Adding a New Library libfoo

To add a new library to the DPDK, proceed as follows:

1. Add a new configuration option:

for f in config/\*; do \
    echo CONFIG_RTE_LIBFOO=y >> $f; done

1. Create a new directory with sources:

mkdir ${RTE_SDK}/lib/libfoo
touch ${RTE_SDK}/lib/libfoo/foo.c
touch ${RTE_SDK}/lib/libfoo/foo.h

1. Add a foo() function in libfoo.

   Definition is in foo.c:

   void foo(void)
   {
   }
   

   Declaration is in foo.h:

   extern void foo(void);
   

2. Update lib/Makefile:

   vi ${RTE_SDK}/lib/Makefile
   # add:
   # DIRS-$(CONFIG_RTE_LIBFOO) += libfoo
   

3. Create a new Makefile for this library, for example, derived from mempool Makefile:

   cp ${RTE_SDK}/lib/librte_mempool/Makefile ${RTE_SDK}/lib/libfoo/
   
   vi ${RTE_SDK}/lib/libfoo/Makefile
   # replace:
   # librte_mempool -> libfoo
   # rte_mempool -> foo
   

4. Update mk/DPDK.app.mk, and add -lfoo in LDLIBS variable when the option is enabled. This will automatically add this flag when linking a DPDK application.

5. Build the DPDK with the new library (we only show a specific target here):

   cd ${RTE_SDK}
   make config T=x86_64-native-linuxapp-gcc
   make
   

6. Check that the library is installed:

   ls build/lib
   ls build/include
   

34.1.1. Example: Using libfoo in the Test Application

The test application is used to validate all functionality of the DPDK. Once you have added a library, a new test case should be added in the test application.

• A new test_foo.c file should be added, that includes foo.h and calls the foo() function from test_foo(). When the test passes, the test_foo() function should return 0.

• Makefile, test.h and commands.c must be updated also, to handle the new test case.

• Test report generation: autotest.py is a script that is used to generate the test report that is available in the ${RTE_SDK}/doc/rst/test_report/autotests directory. This script must be updated also. If libfoo is in a new test family, the links in ${RTE_SDK}/doc/rst/test_report/test_report.rst must be updated.

• Build the DPDK with the updated test application (we only show a specific target here):

  cd ${RTE_SDK}
  make config T=x86_64-native-linuxapp-gcc
  make