plugin: add runtime plugin loader for external capture backends including dpdk

CMakeLists.txt

@@ -2509,6 +2509,25 @@ if(NOT DISABLE_DPDK)
     endif()
 endif()
 
+#
+# Plugin loader — always compiled, discovers pcap-*.so at runtime.
+#
+set(PROJECT_SOURCE_LIST_C ${PROJECT_SOURCE_LIST_C} pcap-plugin.c)
+set(PCAP_LINK_LIBRARIES ${PCAP_LINK_LIBRARIES} ${CMAKE_DL_LIBS})
+
+#
+# Plugin directory (build-time default).
+# Exposed as plugindir in libpcap.pc so external projects can
+# query it with: pkg-config --variable=plugindir libpcap
+#
+set(PLUGIN_DIR "${CMAKE_INSTALL_PREFIX}/lib/pcap/plugins" CACHE STRING
+    "Plugin directory for pcap-*.so modules")
+add_definitions(-DPCAP_PLUGIN_DIR="${PLUGIN_DIR}")
+
+check_function_exists(secure_getenv HAVE_SECURE_GETENV)
+check_function_exists(issetugid HAVE_ISSETUGID)
+check_function_exists(getauxval HAVE_GETAUXVAL)
+
 # Check for Bluetooth sniffing support
 if(NOT DISABLE_BLUETOOTH)
     if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
@@ -3574,6 +3593,7 @@ if(NOT MSVC)
             set(RPATH "")
         endif()
     endif()
+    set(plugindir "${PLUGIN_DIR}")
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/pcap-config.in ${CMAKE_CURRENT_BINARY_DIR}/pcap-config @ONLY)
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpcap.pc.in ${CMAKE_CURRENT_BINARY_DIR}/libpcap.pc @ONLY)
     install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/pcap-config DESTINATION bin)

Makefile.in

@@ -33,6 +33,8 @@ sbindir = @sbindir@
 includedir = @includedir@
 # Pathname of directory to install the library
 libdir =  @libdir@
+# Pathname of directory to install plugin modules
+plugindir = @plugindir@
 # Pathname of directory to install the man pages
 mandir = @mandir@
 
@@ -53,7 +55,7 @@ MKDEP = @MKDEP@
 CCOPT = @V_CCOPT@
 SHLIB_CCOPT = @V_SHLIB_CCOPT@
 INCLS = -I. @V_INCLS@
-DEFS = -DBUILDING_PCAP -Dpcap_EXPORTS @DEFS@ @V_DEFS@
+DEFS = -DBUILDING_PCAP -Dpcap_EXPORTS -DPCAP_PLUGIN_DIR='"$(plugindir)"' @DEFS@ @V_DEFS@
 ADDLOBJS = @ADDLOBJS@
 ADDLARCHIVEOBJS = @ADDLARCHIVEOBJS@
 LIBS = @LIBS@
@@ -114,6 +116,7 @@ PUBHDR = \
 	pcap/nflog.h \
 	pcap/pcap-inttypes.h \
 	pcap/pcap.h \
+	pcap/pcap-plugin.h \
 	pcap/sll.h \
 	pcap/socket.h \
 	pcap/usb.h \
@@ -132,6 +135,7 @@ HDR = $(PUBHDR) \
 	optimize.h \
 	pcap-common.h \
 	pcap-int.h \
+	pcap-plugin.h \
 	pcap-rpcap.h \
 	pcap-types.h \
 	pcap-usb-linux-common.h \
@@ -316,6 +320,8 @@ EXTRA_DIST = \
 	pcap-netmap.h \
 	pcap-npf.c \
 	pcap-null.c \
+	pcap-plugin.c \
+	pcap-plugin.h \
 	pcap-rdmasniff.c \
 	pcap-rdmasniff.h \
 	pcap-rpcap.c \

cmakeconfig.h.in

@@ -42,6 +42,15 @@
 /* Define to 1 if fseeko (and presumably ftello) exists and is declared. */
 #cmakedefine HAVE_FSEEKO 1
 
+/* Define to 1 if you have the `secure_getenv' function. */
+#cmakedefine HAVE_SECURE_GETENV 1
+
+/* Define to 1 if you have the `issetugid' function. */
+#cmakedefine HAVE_ISSETUGID 1
+
+/* Define to 1 if you have the `getauxval' function. */
+#cmakedefine HAVE_GETAUXVAL 1
+
 /* Define to 1 if you have the `getspnam' function. */
 #cmakedefine HAVE_GETSPNAM 1
 

configure.ac

@@ -2999,6 +2999,30 @@ if test "x$enable_rdma" != "xno"; then
 	AC_SUBST(PCAP_SUPPORT_RDMASNIFF)
 fi
 
+#
+# Plugin loader — always compiled, discovers pcap-*.so at runtime.
+# Needs -ldl on systems where dlopen is in libdl (not needed on
+# FreeBSD, musl, etc. where it is in libc).
+#
+MODULE_C_SRC="$MODULE_C_SRC pcap-plugin.c"
+AC_SEARCH_LIBS([dlopen], [dl])
+
+AC_CHECK_FUNCS([secure_getenv issetugid getauxval])
+
+# Plugin directory (build-time default).
+# Exposed as plugindir in libpcap.pc so external projects can
+# query it with: pkg-config --variable=plugindir libpcap
+plugindir='${libdir}/pcap/plugins'
+AC_ARG_WITH([plugin-dir],
+    AS_HELP_STRING([--with-plugin-dir=DIR],
+	[plugin directory @<:@LIBDIR/pcap/plugins@:>@]),
+    [
+	if test "$withval" != no && test "$withval" != yes; then
+		plugindir="$withval"
+	fi
+    ])
+AC_SUBST(plugindir)
+
 #
 # If this is a platform where we need to have the .pc file and
 # pcap-config script supply an rpath option to specify the directory

libpcap.pc.in

@@ -9,6 +9,7 @@ prefix="@prefix@"
 exec_prefix="@exec_prefix@"
 includedir="@includedir@"
 libdir="@libdir@"
+plugindir="@plugindir@"
 
 Name: libpcap
 Description: Platform-independent network traffic capture library

pcap-int.h

@@ -564,10 +564,14 @@ FILE	*pcapint_charset_fopen(const char *path, const char *mode);
  */
 #ifdef _WIN32
 #define pcap_code_handle_t	HMODULE
+#else
+#define pcap_code_handle_t	void *
+#endif
 
 pcap_code_handle_t	pcapint_load_code(const char *);
 void			*pcapint_find_function(pcap_code_handle_t, const char *);
-#endif
+void			pcapint_unload_code(pcap_code_handle_t);
+
 
 /*
  * Internal interfaces for doing user-mode filtering of packets and