cmake: simplify integration of Cohda LLC API

CMakeLists.txt

@@ -62,7 +62,6 @@ endforeach()
 include(CompatBoostTargets)
 find_package(CryptoPP 5.6.1 REQUIRED)
 find_package(GeographicLib 1.37 REQUIRED)
-find_package(Cohda MODULE QUIET)
 
 option(VANETZA_WITH_OPENSSL "Enable OpenSSL extensions" OFF)
 if (VANETZA_WITH_OPENSSL)

tools/socktap/CMakeLists.txt

@@ -30,11 +30,26 @@ add_executable(socktap
 target_link_libraries(socktap PUBLIC Boost::system Boost::program_options Threads::Threads vanetza)
 install(TARGETS socktap EXPORT ${PROJECT_NAME} DESTINATION ${CMAKE_INSTALL_BINDIR})
 
-option(SOCKTAP_WITH_COHDA_LLC "Use Cohda LLC API for socktap" ${COHDA_FOUND})
+find_file(COHDA_LLC_API_HEADER llc-api.c
+    PATHS "/home/duser"
+    PATH_SUFFIXES "cohda/kernel/include/linux/cohda/llc"
+    CMAKE_FIND_ROOT_PATH_BOTH
+    DOC "Cohda LLC API header")
+mark_as_advanced(COHDA_LLC_API_HEADER)
+if(COHDA_LLC_API_HEADER)
+    set(COHDA_LLC_API_FOUND ON)
+else()
+    set(COHDA_LLC_API_FOUND OFF)
+endif()
+
+option(SOCKTAP_WITH_COHDA_LLC "Enable Cohda LLC link layer for socktap" ${COHDA_LLC_API_FOUND})
 if(SOCKTAP_WITH_COHDA_LLC)
-    find_package(Cohda MODULE REQUIRED)
+    if(NOT COHDA_LLC_API_HEADER)
+        message(SEND_ERROR "Cohda LLC API header [llc-api.h] is missing")
+    endif()
+    get_filename_component(COHDA_LLC_INCLUDE_DIR ${COHDA_LLC_API_HEADER} DIRECTORY)
     target_compile_definitions(socktap PUBLIC "SOCKTAP_WITH_COHDA_LLC")
-    target_include_directories(socktap PUBLIC ${COHDA_INCLUDE_DIRS})
+    target_include_directories(socktap PUBLIC ${COHDA_LLC_INCLUDE_DIR})
     target_sources(socktap PRIVATE cohda.cpp cohda_link.cpp)
 endif()