FindPCAP.cmake

# - Try to find libpcap include dirs and libraries
#
# Usage of this module as follows:
#
#     find_package(PCAP)
#
# Variables used by this module, they can change the default behaviour and need
# to be set before calling find_package:
#
#  PCAP_ROOT_DIR             Set this variable to the root installation of
#                            libpcap if the module has problems finding the
#                            proper installation path.
#
# Variables defined by this module:
#
#  PCAP_FOUND                System has libpcap, include and library dirs found
#  PCAP_INCLUDE_DIR          The libpcap include directories.
#  PCAP_LIBRARY              The libpcap library (possibly includes a thread
#                            library e.g. required by pf_ring's libpcap)
#  HAVE_PF_RING              If a found version of libpcap supports PF_RING

find_path(PCAP_ROOT_DIR NAMES include/pcap.h Include/pcap.h)

# If this is MSVC and a different root path was provided to cmake, add the vcpkg paths to
# the list of ignored paths for the rest of this file. This prevents cmake from preferring
# vcpkg over the path requested.
set(_old_cmake_ignore_path ${CMAKE_IGNORE_PATH})
string(FIND "${PCAP_ROOT_DIR}" "vcpkg" _is_vcpkg_root)
if (MSVC AND _is_vcpkg_root LESS 0)
    set(CMAKE_IGNORE_PATH ${VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}/include)
    list(APPEND CMAKE_IGNORE_PATH ${VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}/debug/lib)
    list(APPEND CMAKE_IGNORE_PATH ${VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}/lib)
endif ()

find_path(PCAP_INCLUDE_DIR NAMES pcap.h HINTS ${PCAP_ROOT_DIR}/include ${PCAP_ROOT_DIR}/Include)

if (MSVC AND COMPILER_ARCHITECTURE STREQUAL "x86_64")
    set(_pcap_lib_hint_path ${PCAP_ROOT_DIR}/lib/x64)
else ()
    set(_pcap_lib_hint_path ${PCAP_ROOT_DIR}/lib)
endif ()

if (MSVC)
    find_library(PCAP_LIBRARY NAMES pcap_static wpcap HINTS ${_pcap_lib_hint_path})
else ()
    find_library(PCAP_LIBRARY NAMES pcap wpcap HINTS ${_pcap_lib_hint_path})
endif ()

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(PCAP DEFAULT_MSG PCAP_LIBRARY PCAP_INCLUDE_DIR)

include(CheckCSourceCompiles)
set(CMAKE_REQUIRED_LIBRARIES ${PCAP_LIBRARY})
check_c_source_compiles("int main() { return 0; }" PCAP_LINKS_SOLO)
set(CMAKE_REQUIRED_LIBRARIES)

# check if linking against libpcap also needs to link against a thread library
if (NOT PCAP_LINKS_SOLO)
    find_package(Threads)
    if (THREADS_FOUND)
        set(CMAKE_REQUIRED_LIBRARIES ${PCAP_LIBRARY} ${CMAKE_THREAD_LIBS_INIT})
        check_c_source_compiles("int main() { return 0; }" PCAP_NEEDS_THREADS)
        set(CMAKE_REQUIRED_LIBRARIES)
    endif ()
    if (THREADS_FOUND AND PCAP_NEEDS_THREADS)
        set(_tmp ${PCAP_LIBRARY} ${CMAKE_THREAD_LIBS_INIT})
        list(REMOVE_DUPLICATES _tmp)
        set(PCAP_LIBRARY ${_tmp} CACHE STRING "Libraries needed to link against libpcap" FORCE)
    else ()
        message(FATAL_ERROR "Couldn't determine how to link against libpcap")
    endif ()
endif ()

string(FIND "${PCAP_LIBRARY}" "wpcap" _pcap_lib_is_wpcap)
if (_pcap_lib_is_wpcap GREATER_EQUAL 0)
    set(HAVE_WPCAP TRUE)
endif ()

include(CheckFunctionExists)
set(CMAKE_REQUIRED_LIBRARIES ${PCAP_LIBRARY})
check_function_exists(pcap_get_pfring_id HAVE_PF_RING)
check_function_exists(pcap_dump_open_append HAVE_PCAP_DUMP_OPEN_APPEND)
set(CMAKE_REQUIRED_LIBRARIES)

mark_as_advanced(PCAP_ROOT_DIR PCAP_INCLUDE_DIR PCAP_LIBRARY)
set(CMAKE_IGNORE_PATH ${_old_cmake_ignore_path})