I'm facing this issue: could not determine kind of name for C.BPF_MAP_TYPE_BLOOM_FILTER

[pratikjagrut]

Hi,

I'm diving into this library for the first time, and I'm pretty new when it comes to eBPF applications. While trying to build one of the apps I'm tinkering with using the libbpfgo library, I ran into this snag:

   ⨯ build failed after 2.17s error=failed to build for linux_amd64: exit status 1: # github.com/aquasecurity/libbpfgo
../../../../go/pkg/mod/github.com/aquasecurity/libbpfgo@v0.6.0-libbpf-1.3/map-common.go:51:39: could not determine kind of name for C.BPF_MAP_TYPE_BLOOM_FILTER

I've got this feeling it might be a versioning or compatibility thing on my end, but I'm a bit stumped. Could someone help me figuring this out?

bpftool --version

bpftool v7.3.0
using libbpf v1.3
features:

[geyslan]

Hey @pratikjagrut, you're see the version used by bpftool. Could you check the system installed one?

For more on how to use libbpfgo see #400 (comment).

[pratikjagrut]

@geyslan I don't see libbpf_version.h file at that location.

[geyslan]

I mentioned the version file to pinpoint where you could check your system libbpf version. Anyway, if you're facing such error, it is certainly related to the lack of definition in your includes.

Please check your build process and the -I flag to find out where it points. If you're not using, it will try to include it from the system path. Mine has BPF_MAP_TYPE_BLOOM_FILTER defined.

❯ grep -ir 'BPF_MAP_TYPE_BLOOM_FILTER' /usr/include/linux 
/usr/include/linux/bpf.h:	BPF_MAP_TYPE_BLOOM_FILTER,
/usr/include/linux/bpf.h:		 * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the

Anyhow, I would recommend you to follow the selftest building way (static compilation), since it uses the correct libbpf version downloaded with libbpfgo. It's kept locally, not installed to the system.

libbpfgo/selftest/common/Makefile

Lines 17 to 18 in 90dbfff

	CGO_CFLAGS_STATIC = "-I$(abspath $(OUTPUT)) -I$(abspath ../common)"
	CGO_LDFLAGS_STATIC = "-lelf -lz $(LIBBPF_OBJ)"

libbpfgo/selftest/common/Makefile

Lines 57 to 64 in 90dbfff

	$(MAIN)-static: libbpfgo-static | $(MAIN).bpf.o
	CC=$(CLANG) \
	CGO_CFLAGS=$(CGO_CFLAGS_STATIC) \
	CGO_LDFLAGS=$(CGO_LDFLAGS_STATIC) \
	GOOS=linux GOARCH=$(ARCH) \
	$(GO) build \
	-tags netgo -ldflags $(CGO_EXTLDFLAGS_STATIC) \
	-o $(MAIN)-static ./$(MAIN).go

[pratikjagrut]

Our build target is configured as follows:

BASEDIR = $(abspath ./)
OUTPUT = ./output
ARCH := $(shell uname -m | sed 's/x86_64/amd64/g; s/aarch64/arm64/g')

LIBBPF_SRC = $(abspath ./3rdparty/libbpf/src)
LIBBPF_OBJ = $(abspath $(OUTPUT)/libbpf.a)
LIBBPF_OBJDIR = $(abspath $(OUTPUT)/libbpf)
LIBBPF_DESTDIR = $(abspath $(OUTPUT))

CC = gcc
CLANG = clang
GO = go
CFLAGS = -g -O2 -Wall -fpie
LDFLAGS =

CGO_CFLAGS_STATIC = "-I$(abspath $(OUTPUT)) -Wno-unknown-attributes"
CGO_LDFLAGS_STATIC = "-lelf -lz $(LIBBPF_OBJ)"
CGO_EXTLDFLAGS_STATIC = '-w -extldflags "-static"'
CGO_CFGLAGS_DYN = "-I. -I/usr/include/"
CGO_LDFLAGS_DYN = "-lelf -lz -lbpf"

libbpf version is the latest one commit 20c0a9e3d7e7d4aeb283eae982543c9cacc29477 (HEAD, tag: v1.3.0)
When executed, it generates the output/vmlinux.h file containing the definition for BPF_MAP_TYPE_BLOOM_FILTER.

[geyslan]

The tracee building might help you identify what's wrong:

https://github.com/aquasecurity/tracee/blob/main/Makefile#L314-L371