From 26681fa6a6fcbec0024906eb8367e9a3160521fb Mon Sep 17 00:00:00 2001
From: Tony Ambardar <itugrok@yahoo.com>
Date: Fri, 23 Nov 2018 16:33:45 -0800
Subject: [PATCH] iproute2: simplify linking libelf for eBFP/XDP object file
 support

Simplify build and runtime dependencies on libelf, which allows tc and ip
to load BPF and XDP object files respectively.

Preserve optionality of libelf by having configuration script follow the
HAVE_ELF environment variable, used similarly to the HAVE_MNL variable.

Signed-off-by: Tony Ambardar <itugrok@yahoo.com>
---
 package/network/utils/iproute2/Makefile       | 11 +++-
 .../patches/145-keep_libelf_optional.patch    | 11 ++++
 .../patches/190-link-libelf-to-tc-only.patch  | 60 -------------------
 3 files changed, 21 insertions(+), 61 deletions(-)
 create mode 100644 package/network/utils/iproute2/patches/145-keep_libelf_optional.patch
 delete mode 100644 package/network/utils/iproute2/patches/190-link-libelf-to-tc-only.patch

diff --git a/package/network/utils/iproute2/Makefile b/package/network/utils/iproute2/Makefile
index 56a16d095c..a9bcfd40a0 100644
--- a/package/network/utils/iproute2/Makefile
+++ b/package/network/utils/iproute2/Makefile
@@ -49,7 +49,7 @@ $(call Package/iproute2/Default)
  VARIANT:=full
  PROVIDES:=ip
  ALTERNATIVES:=300:/sbin/ip:/usr/libexec/ip-full
- DEPENDS:=+libnl-tiny +(PACKAGE_devlink||PACKAGE_rdma):libmnl
+ DEPENDS:=+libnl-tiny +libelf +(PACKAGE_devlink||PACKAGE_rdma):libmnl
 endef
 
 define Package/tc
@@ -100,6 +100,14 @@ ifeq ($(BUILD_VARIANT),tiny)
   IP_CONFIG_TINY:=y
 endif
 
+ifeq ($(BUILD_VARIANT),full)
+  HAVE_ELF:=y
+endif
+
+ifeq ($(BUILD_VARIANT),tc)
+  HAVE_ELF:=y
+endif
+
 ifdef CONFIG_PACKAGE_devlink
   HAVE_MNL:=y
 endif
@@ -121,6 +129,7 @@ MAKE_FLAGS += \
 	KERNEL_INCLUDE="$(LINUX_DIR)/user_headers/include" \
 	SHARED_LIBS="" \
 	IP_CONFIG_TINY=$(IP_CONFIG_TINY) \
+	HAVE_ELF=$(HAVE_ELF) \
 	HAVE_MNL=$(HAVE_MNL) \
 	IPT_LIB_DIR=/usr/lib/iptables \
 	XT_LIB_DIR=/usr/lib/iptables \
diff --git a/package/network/utils/iproute2/patches/145-keep_libelf_optional.patch b/package/network/utils/iproute2/patches/145-keep_libelf_optional.patch
new file mode 100644
index 0000000000..2e3ad18809
--- /dev/null
+++ b/package/network/utils/iproute2/patches/145-keep_libelf_optional.patch
@@ -0,0 +1,11 @@
+--- a/configure
++++ b/configure
+@@ -228,7 +228,7 @@ EOF
+ 
+ check_elf()
+ {
+-    if ${PKG_CONFIG} libelf --exists; then
++    if [ "${HAVE_ELF}" = "y" ] && ${PKG_CONFIG} libelf --exists; then
+ 	echo "HAVE_ELF:=y" >>$CONFIG
+ 	echo "yes"
+ 
diff --git a/package/network/utils/iproute2/patches/190-link-libelf-to-tc-only.patch b/package/network/utils/iproute2/patches/190-link-libelf-to-tc-only.patch
deleted file mode 100644
index 31aacffba8..0000000000
--- a/package/network/utils/iproute2/patches/190-link-libelf-to-tc-only.patch
+++ /dev/null
@@ -1,60 +0,0 @@
---- a/configure
-+++ b/configure
-@@ -231,8 +231,9 @@ check_elf()
- 	echo "HAVE_ELF:=y" >>$CONFIG
- 	echo "yes"
- 
--	echo 'CFLAGS += -DHAVE_ELF' `${PKG_CONFIG} libelf --cflags` >> $CONFIG
--	echo 'LDLIBS += ' `${PKG_CONFIG} libelf --libs` >>$CONFIG
-+	echo 'CFLAGS += -DHAVE_ELF' >> $CONFIG
-+	echo 'ELF_CFLAGS += ' `${PKG_CONFIG} libelf --cflags` >> $CONFIG
-+	echo 'ELF_LDLIBS += ' `${PKG_CONFIG} libelf --libs` >>$CONFIG
-     else
- 	echo "no"
-     fi
---- a/lib/Makefile
-+++ b/lib/Makefile
-@@ -11,9 +11,17 @@ UTILOBJ = utils.o rt_names.o ll_map.o ll
- 	inet_proto.o namespace.o json_writer.o json_print.o \
- 	names.o color.o bpf.o exec.o fs.o
- 
-+ELFOBJ=$(patsubst %.o,%.elf.o,$(UTILOBJ))
-+
- NLOBJ=libgenl.o libnetlink.o
- 
--all: libnetlink.a libutil.a
-+all: libnetlink.a libutil.a libutil-elf.a
-+
-+%.o: %.c
-+	$(QUIET_CC)$(CC) $(CFLAGS) -UHAVE_ELF $(EXTRA_CFLAGS) -c -o $@ $<
-+
-+%.elf.o: %.c
-+	$(QUIET_CC)$(CC) $(CFLAGS) $(ELF_CFLAGS) $(EXTRA_CFLAGS) -c -o $@ $<
- 
- libnetlink.a: $(NLOBJ)
- 	$(QUIET_AR)$(AR) rcs $@ $^
-@@ -21,7 +29,10 @@ libnetlink.a: $(NLOBJ)
- libutil.a: $(UTILOBJ) $(ADDLIB)
- 	$(QUIET_AR)$(AR) rcs $@ $^
- 
-+libutil-elf.a: $(ELFOBJ) $(ADDLIB)
-+	$(QUIET_AR)$(AR) rcs $@ $^
-+
- install:
- 
- clean:
--	rm -f $(NLOBJ) $(UTILOBJ) $(ADDLIB) libnetlink.a libutil.a
-+	rm -f $(NLOBJ) $(UTILOBJ) $(ELFOBJ) $(ADDLIB) libnetlink.a libutil.a libutil-elf.a
---- a/tc/Makefile
-+++ b/tc/Makefile
-@@ -133,8 +133,8 @@ MODDESTDIR := $(DESTDIR)$(LIBDIR)/tc
- 
- all: tc $(TCSO)
- 
--tc: $(TCOBJ) $(LIBNETLINK) libtc.a
--	$(QUIET_LINK)$(CC) $^ $(LDFLAGS) $(LDLIBS) -o $@
-+tc: $(TCOBJ) $(subst libutil.a,libutil-elf.a,$(LIBNETLINK)) libtc.a
-+	$(QUIET_LINK)$(CC) $^ $(LDFLAGS) $(LDLIBS) $(ELF_LDLIBS) -o $@
- 
- libtc.a: $(TCLIB)
- 	$(QUIET_AR)$(AR) rcs $@ $^
-- 
2.30.2