when CONFIG_NF_CONNTRACK=m, vmlinux BTF does not contain
BPF_F_CURRENT_NETNS or bpf_ct_opts; they are both found in nf_conntrack
BTF; for example:
bpftool btf dump file /sys/kernel/btf/nf_conntrack|grep ct_opts
[114754] STRUCT 'bpf_ct_opts' size=12 vlen=5
This causes compilation errors as follows:
CLNG-BPF [test_maps] xdp_synproxy_kern.o
progs/xdp_synproxy_kern.c:83:14: error: declaration of 'struct bpf_ct_opts' will not be visible outside of this function [-Werror,-Wvisibility]
struct bpf_ct_opts *opts,
^
progs/xdp_synproxy_kern.c:89:14: error: declaration of 'struct bpf_ct_opts' will not be visible outside of this function [-Werror,-Wvisibility]
struct bpf_ct_opts *opts,
^
progs/xdp_synproxy_kern.c:397:15: error: use of undeclared identifier 'BPF_F_CURRENT_NETNS'; did you mean 'BPF_F_CURRENT_CPU'?
.netns_id = BPF_F_CURRENT_NETNS,
^~~~~~~~~~~~~~~~~~~
BPF_F_CURRENT_CPU
tools/testing/selftests/bpf/tools/include/vmlinux.h:43115:2: note: 'BPF_F_CURRENT_CPU' declared here
BPF_F_CURRENT_CPU = 4294967295,
While tools/testing/selftests/bpf/config does specify
CONFIG_NF_CONNTRACK=y, it would be good to use this case to show
how we can generate a module header file via split BTF.
In the selftests Makefile, we define NF_CONNTRACK BTF via VMLINUX_BTF
(thus gaining the path determination logic it uses). If the nf_conntrack
BTF file exists (which means it is built as a module), we run
"bpftool btf dump" to generate module BTF, and if not we simply copy
vmlinux.h to nf_conntrack.h; this allows us to avoid having to pass
a #define or deal with CONFIG variables in the program.
With these changes the test builds and passes:
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/testing/selftests/bpf/Makefile | 11 +++++++++++
tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index cb8e552..a5fa636 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -141,6 +141,8 @@ VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
ifeq ($(VMLINUX_BTF),)
$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
endif
+# If nf_conntrack is a module, need BTF for it also
+NF_CONNTRACK_BTF ?= $(shell dirname $(VMLINUX_BTF))/nf_conntrack
# Define simple and short `make test_progs`, `make test_sysctl`, etc targets
# to build individual tests.
@@ -280,6 +282,14 @@ else
$(Q)cp "$(VMLINUX_H)" $@
endif
+$(INCLUDE_DIR)/nf_conntrack.h: $(INCLUDE_DIR)/vmlinux.h
+ifneq ("$(wildcard $(NF_CONNTRACK_BTF))","")
+ $(call msg,GEN,,$@)
+ $(BPFTOOL) btf dump file $(NF_CONNTRACK_BTF) format c > $@
+else
+ $(Q)cp $(INCLUDE_DIR)/vmlinux.h $@
+endif
+
$(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids \
$(TOOLSDIR)/bpf/resolve_btfids/main.c \
$(TOOLSDIR)/lib/rbtree.c \
@@ -417,6 +427,7 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.o: \
$(TRUNNER_BPF_PROGS_DIR)/%.c \
$(TRUNNER_BPF_PROGS_DIR)/*.h \
$$(INCLUDE_DIR)/vmlinux.h \
+ $$(INCLUDE_DIR)/nf_conntrack.h \
$(wildcard $(BPFDIR)/bpf_*.h) \
$(wildcard $(BPFDIR)/*.bpf.h) \
| $(TRUNNER_OUTPUT) $$(BPFOBJ)
diff --git a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
index 9fd62e9..8c5f46e 100644
--- a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
+++ b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
/* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
-#include "vmlinux.h"
+#include "nf_conntrack.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
--
1.8.3.1
