cmake: Build bpf

CMakeLists.txt

@@ -64,6 +64,7 @@ find_package(ZLIB 1.2.3)
 find_package(Libngtcp2 0.0.0)
 find_package(Libngtcp2_crypto_openssl 0.0.0)
 find_package(Libnghttp3 0.0.0)
+find_package(Libbpf 0.4.0)
 if(OPENSSL_FOUND AND LIBEV_FOUND AND ZLIB_FOUND)
   set(ENABLE_APP_DEFAULT ON)
 else()
@@ -235,6 +236,20 @@ if(ENABLE_ASIO_LIB)
   find_package(Boost 1.54.0 REQUIRED system thread)
 endif()
 
+# libbpf (for bpf)
+set(HAVE_LIBBPF ${LIBBPF_FOUND})
+if(LIBBPF_FOUND)
+  set(BPFCFLAGS -Wall -O2 -g)
+  if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    # For Debian/Ubuntu
+    set(EXTRABPFCFLAGS -I/usr/include/${CMAKE_SYSTEM_PROCESSOR}-linux-gnu)
+  endif()
+
+  check_c_source_compiles("
+#include <linux/bpf.h>
+int main() { enum bpf_stats_type foo; (void)foo; }" HAVE_BPF_STATS_TYPE)
+endif()
+
 # The nghttp, nghttpd and nghttpx under src depend on zlib, OpenSSL and libev
 if(ENABLE_APP AND NOT (ZLIB_FOUND AND OPENSSL_FOUND AND LIBEV_FOUND))
   message(FATAL_ERROR "Applications were requested (ENABLE_APP=1) but dependencies are not met.")
@@ -492,6 +507,7 @@ add_subdirectory(integration-tests)
 add_subdirectory(doc)
 add_subdirectory(contrib)
 add_subdirectory(script)
+add_subdirectory(bpf)
 
 
 string(TOUPPER "${CMAKE_BUILD_TYPE}" _build_type)
@@ -525,6 +541,7 @@ message(STATUS "summary of build options:
       Libngtcp2:      ${HAVE_LIBNGTCP2} (LIBS='${LIBNGTCP2_LIBRARIES}')
       Libngtcp2_crypto_openssl: ${HAVE_LIBNGTCP2_CRYPTO_OPENSSL} (LIBS='${LIBNGTCP2_CRYPTO_OPENSSL_LIBRARIES}')
       Libnghttp3:     ${HAVE_LIBNGHTTP3} (LIBS='${LIBNGHTTP3_LIBRARIES}')
+      Libbpf:         ${HAVE_LIBBPF} (LIBS='${LIBBPF_LIBRARIES}')
       Libevent(SSL):  ${HAVE_LIBEVENT_OPENSSL} (LIBS='${LIBEVENT_OPENSSL_LIBRARIES}')
       Jansson:        ${HAVE_JANSSON} (LIBS='${JANSSON_LIBRARIES}')
       Jemalloc:       ${HAVE_JEMALLOC} (LIBS='${JEMALLOC_LIBRARIES}')

bpf/CMakeLists.txt

+if(LIBBPF_FOUND)
+  add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o"
+    COMMAND ${CMAKE_C_COMPILER} ${BPFCFLAGS} ${EXTRABPFCFLAGS} -I${LIBBPF_INCLUDE_DIRS} -target bpf -c reuseport_kern.c -o "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o"
+    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+    VERBATIM)
+
+  add_custom_target(bpf ALL
+    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o"
+    VERBATIM)
+
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/reuseport_kern.o"
+    DESTINATION "${CMAKE_INSTALL_LIBDIR}/${CMAKE_PROJECT_NAME}")
+endif()

cmake/FindLibbpf.cmake

+# - Try to find libbpf
+# Once done this will define
+#  LIBBPF_FOUND        - System has libbpf
+#  LIBBPF_INCLUDE_DIRS - The libbpf include directories
+#  LIBBPF_LIBRARIES    - The libraries needed to use libbpf
+
+find_package(PkgConfig QUIET)
+pkg_check_modules(PC_LIBBPF QUIET libbpf)
+
+find_path(LIBBPF_INCLUDE_DIR
+  NAMES bpf/bpf.h
+  HINTS ${PC_LIBBPF_INCLUDE_DIRS}
+)
+find_library(LIBBPF_LIBRARY
+  NAMES bpf
+  HINTS ${PC_LIBBPF_LIBRARY_DIRS}
+)
+
+include(FindPackageHandleStandardArgs)
+# handle the QUIETLY and REQUIRED arguments and set LIBBPF_FOUND
+# to TRUE if all listed variables are TRUE and the requested version
+# matches.
+find_package_handle_standard_args(Libbpf REQUIRED_VARS
+                                  LIBBPF_LIBRARY LIBBPF_INCLUDE_DIR
+                                  VERSION_VAR LIBBPF_VERSION)
+
+if(LIBBPF_FOUND)
+  set(LIBBPF_LIBRARIES     ${LIBBPF_LIBRARY})
+  set(LIBBPF_INCLUDE_DIRS  ${LIBBPF_INCLUDE_DIR})
+endif()
+
+mark_as_advanced(LIBBPF_INCLUDE_DIR LIBBPF_LIBRARY)

cmakeconfig.h.in

@@ -81,3 +81,9 @@
 
 /* Define to 1 if HTTP/3 is enabled. */
 #cmakedefine ENABLE_HTTP3 1
+
+/* Define to 1 if you have `libbpf` library. */
+#cmakedefine HAVE_LIBBPF 1
+
+/* Define to 1 if you have enum bpf_stats_type in linux/bpf.h. */
+#cmakedefine HAVE_BPF_STATS_TYPE 1

src/CMakeLists.txt

@@ -22,6 +22,7 @@ include_directories(
   ${LIBCARES_INCLUDE_DIRS}
   ${JANSSON_INCLUDE_DIRS}
   ${ZLIB_INCLUDE_DIRS}
+  ${LIBBPF_INCLUDE_DIRS}
 )
 
 # XXX per-target?
@@ -38,6 +39,7 @@ link_libraries(
   ${JANSSON_LIBRARIES}
   ${ZLIB_LIBRARIES}
   ${APP_LIBRARIES}
+  ${LIBBPF_LIBRARIES}
 )
 
 if(ENABLE_APP)