From ff3e4272ff46f1187f53c3d20275b9e9df14e2e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
Date: Fri, 15 Oct 2021 13:27:49 +0200
Subject: [PATCH] Integrate libxdp as a submodule
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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    |  3 +++
 configure      | 45 +++++++++++++++++++++++++++++++++++++++++++--
 lib/.gitignore |  1 +
 lib/Makefile   | 41 ++++++++++++++++++++++++++++++++++-------
 lib/common.mk  |  3 +++
 lib/xdp-tools  |  1 +
 6 files changed, 85 insertions(+), 9 deletions(-)
 create mode 100644 lib/.gitignore
 create mode 160000 lib/xdp-tools

diff --git a/.gitmodules b/.gitmodules
index a06b6a0..3ce07b7 100644
--- a/.gitmodules
+++ b/.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
diff --git a/configure b/configure
index 48b9504..966b9ff 100755
--- a/configure
+++ b/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
 
diff --git a/lib/.gitignore b/lib/.gitignore
new file mode 100644
index 0000000..36d5277
--- /dev/null
+++ b/lib/.gitignore
@@ -0,0 +1 @@
+lib-install
diff --git a/lib/Makefile b/lib/Makefile
index 7550e64..bbcbfd6 100644
--- a/lib/Makefile
+++ b/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
diff --git a/lib/common.mk b/lib/common.mk
index 811bab0..1a6a264 100644
--- a/lib/common.mk
+++ b/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
 
diff --git a/lib/xdp-tools b/lib/xdp-tools
new file mode 160000
index 0000000..27cbd72
--- /dev/null
+++ b/lib/xdp-tools
@@ -0,0 +1 @@
+Subproject commit 27cbd728e210da926d9e8584954cf6e0a1d4d2a0