Integrate libxdp as a submodule

This adds libxdp as a submodule and link target alongside libbpf. This
should make it just as easy for examples to use libxdp as it currently is
for libbpf. Some hoops need to be jumped through to make libxdp link
against the same version of libbpf as the one we use in this repository.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>

.gitmodules

@@ -2,3 +2,6 @@
 	path = lib/libbpf
 	url = https://github.com/xdp-project/libbpf.git
 	ignore = dirty
+[submodule "lib/xdp-tools"]
+	path = lib/xdp-tools
+	url = https://github.com/xdp-project/xdp-tools

configure

@@ -11,6 +11,8 @@ CONFIG=".${CONFIG}.tmp"
 TMPDIR=$(mktemp -d config.XXXXXX)
 trap 'status=$?; rm -rf $TMPDIR; rm -f $CONFIG; exit $status' EXIT HUP INT QUIT TERM
 
+SUBMODULE_LIBBPF=0
+
 check_toolchain()
 {
     local clang_version
@@ -123,9 +125,10 @@ EOF
     fi
 
     echo submodule
+    SUBMODULE_LIBBPF=1
     echo "SYSTEM_LIBBPF:=n" >> $CONFIG
-    echo 'CFLAGS += -I$(LIB_DIR)/libbpf-install/usr/include' >>$CONFIG
-    echo 'BPF_CFLAGS += -I$(LIB_DIR)/libbpf-install/usr/include' >>$CONFIG
+    echo 'CFLAGS += -I$(LIB_DIR)/lib-install/usr/include' >>$CONFIG
+    echo 'BPF_CFLAGS += -I$(LIB_DIR)/lib-install/usr/include' >>$CONFIG
     echo 'LDFLAGS += -L$(LIB_DIR)/libbpf/src' >>$CONFIG
     echo 'LDLIBS += -l:libbpf.a' >>$CONFIG
     echo 'OBJECT_LIBBPF = $(LIB_DIR)/libbpf/src/libbpf.a' >>$CONFIG
@@ -173,6 +176,42 @@ EOF
     fi
 }
 
+check_libxdp()
+{
+    if [ "${FORCE_SUBMODULE_LIBXDP:-0}" -ne "1" ] && ${PKG_CONFIG} libxdp --exists; then
+
+        LIBXDP_CFLAGS=$(${PKG_CONFIG} libxdp --cflags)
+        LIBXDP_LDLIBS=$(${PKG_CONFIG} libxdp --libs)
+        echo "SYSTEM_LIBXDP:=y" >>$CONFIG
+        echo 'CFLAGS += ' $LIBXDP_CFLAGS >> $CONFIG
+        echo 'LDLIBS += ' $LIBXDP_LDLIBS >>$CONFIG
+        echo 'OBJECT_LIBXDP = ' >>$CONFIG
+        echo system
+
+        return 0
+    fi
+
+    echo submodule
+    echo "SYSTEM_LIBXDP:=n" >> $CONFIG
+    if [ "$SUBMODULE_LIBBPF" -eq "1" ]; then
+        echo "Configuring libxdp to use our libbpf submodule"
+        (export LIBBPF_DIR="$(readlink -m lib/libbpf)" LIBBPF_INCLUDE_DIR="$(readlink -m lib/lib-install/usr/include)";
+         cd lib/xdp-tools; ./configure)
+    else
+        echo "Configuring libxdp without our libbpf"
+        (cd lib/xdp-tools; ./configure)
+        # these are already set if using libbpf as a submodule
+        echo 'CFLAGS += -I$(LIB_DIR)/lib-install/usr/include' >>$CONFIG
+        echo 'BPF_CFLAGS += -I$(LIB_DIR)/lib-install/usr/include' >>$CONFIG
+    fi
+    echo 'LDFLAGS += -L$(LIB_DIR)/lib-install/usr/lib' >>$CONFIG
+    echo 'LDLIBS += -l:libxdp.a' >>$CONFIG
+    echo 'OBJECT_LIBXDP = $(LIB_DIR)/lib-install/usr/lib/libxdp.a' >>$CONFIG
+    if ! [ -d "lib/xdp-tools/lib" ] && [ -f ".gitmodules" ] && [ -e ".git" ]; then
+        git submodule init && git submodule update
+    fi
+}
+
 quiet_config()
 {
     cat <<EOF
@@ -211,6 +250,8 @@ check_toolchain
 
 echo -n "libbpf support: "
 check_libbpf
+echo -n "libxdp support: "
+check_libxdp
 
 check_bpf_use_errno
 

lib/.gitignore

@@ -0,0 +1 @@
+lib-install

lib/Makefile

@@ -2,17 +2,18 @@
 LIBBPF_CFLAGS:=$(if $(CFLAGS),$(CFLAGS),-g -O2 -Werror -Wall) -fPIC
 
 LIB_DIR = .
+LIB_INSTALL := lib-install
 include defines.mk
 
 SUBDIRS=
 
-all: $(OBJECT_LIBBPF)
+all: $(OBJECT_LIBBPF) $(OBJECT_LIBXDP)
 	@set -e; \
 	for i in $(SUBDIRS); \
 	do echo; echo "  $$i"; $(MAKE) -C $$i; done
 
 .PHONY: clean
-clean: libbpf_clean
+clean: libbpf_clean libxdp_clean
 	@for i in $(SUBDIRS); \
 	do $(MAKE) -C $$i clean; done
 
@@ -21,7 +22,9 @@ install:
 	$(MAKE) -C libxdp install
 	$(MAKE) -C testing install
 
+
 libbpf: $(OBJECT_LIBBPF)
+libxdp: libbpf $(OBJECT_LIBXDP)
 
 # Handle libbpf as git submodule
 ifeq ($(SYSTEM_LIBBPF),n)
@@ -31,21 +34,45 @@ endif
 
 # Detect submodule libbpf source file changes
 LIBBPF_SOURCES := $(wildcard libbpf/src/*.[ch])
-LIBBPF_INSTALL := libbpf-install
-INSTDIR=../../$(LIBBPF_INSTALL)
 
-.PHONY: libbpf_clean
 libbpf/src/libbpf.a: $(LIBBPF_SOURCES)
 	@echo ; echo "  libbpf"
 	$(QUIET_CC)$(MAKE) -C libbpf/src CFLAGS="$(LIBBPF_CFLAGS)" $P
-	$(QUIET_INSTALL)$(MAKE) -C libbpf/src DESTDIR=$(INSTDIR) install_headers $P
+	$(QUIET_INSTALL)$(MAKE) -C libbpf/src DESTDIR=../../$(LIB_INSTALL) install_headers $P
 
+.PHONY: libbpf_clean
 libbpf_clean:
 	$(Q)$(MAKE) -C libbpf/src clean $P
-	$(Q)$(RM) -r $(LIBBPF_INSTALL)
+	$(Q)$(RM) -r $(LIB_INSTALL)
 
 else
 
 libbpf_clean:
 	@echo -n
 endif
+
+# Handle libbpf as git submodule
+ifeq ($(SYSTEM_LIBXDP),n)
+ifeq ($(VERBOSE),0)
+P:= >/dev/null
+endif
+
+# Detect submodule libbpf source file changes
+LIBXDP_SOURCES := $(wildcard xdp-tools/lib/libxdp/*.[ch])
+
+
+$(LIB_INSTALL)/usr/lib/libxdp.a: $(LIBXDP_SOURCES)
+	@echo ; echo "  libxdp"
+	$(QUIET_CC)$(MAKE) -C xdp-tools BUILD_STATIC_ONLY=1 libxdp  $P
+	$(QUIET_INSTALL)$(MAKE) -C xdp-tools DESTDIR=../../../$(LIB_INSTALL) PREFIX=/usr BUILD_STATIC_ONLY=1 libxdp_install $P
+
+.PHONY: libxdp_clean
+libxdp_clean:
+	$(Q)$(MAKE) -C xdp-tools clean $P
+	$(Q)$(RM) -r $(LIB_INSTALL)
+
+else
+
+libxdp_clean:
+	@echo -n
+endif

lib/common.mk

@@ -61,6 +61,9 @@ clean::
 $(OBJECT_LIBBPF): $(LIBBPF_SOURCES)
 	$(Q)$(MAKE) -C $(LIB_DIR) libbpf
 
+$(OBJECT_LIBXDP): $(LIBXDP_SOURCES)
+	$(Q)$(MAKE) -C $(LIB_DIR) libxdp
+
 $(CONFIGMK):
 	$(Q)$(MAKE) -C $(LIB_DIR)/.. config.mk