flow_dissector: fix build failure without CONFIG_NET (2dfd184a) · Commits · 戴 / test

If boolean CONFIG_BPF_SYSCALL is enabled, kernel/bpf/syscall.c will call flow_dissector functions from net/core/flow_dissector.c. This causes this build failure if CONFIG_NET is disabled: kernel/bpf/syscall.o: In function `__x64_sys_bpf': syscall.c:(.text+0x3278): undefined reference to `skb_flow_dissector_bpf_prog_attach' syscall.c:(.text+0x3310): undefined reference to `skb_flow_dissector_bpf_prog_detach' kernel/bpf/syscall.o:(.rodata+0x3f0): undefined reference to `flow_dissector_prog_ops' kernel/bpf/verifier.o:(.rodata+0x250): undefined reference to `flow_dissector_verifier_ops' Analogous to other optional BPF program types in syscall.c, add stubs if the relevant functions are not compiled and move the BPF_PROG_TYPE definition in the #ifdef CONFIG_NET block. Fixes: ("flow_dissector: implements flow dissector BPF hook") Reported-by:

Randy Dunlap <rdunlap@infradead.org> Signed-off-by:

Willem de Bruijn <willemb@google.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Acked-by:

Yonghong Song <yhs@fb.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net>

include/linux/bpf_types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_SEG6LOCAL, lwt_seg6local)
		BPF_PROG_TYPE(BPF_PROG_TYPE_SOCK_OPS, sock_ops)
		BPF_PROG_TYPE(BPF_PROG_TYPE_SK_SKB, sk_skb)
		BPF_PROG_TYPE(BPF_PROG_TYPE_SK_MSG, sk_msg)
		BPF_PROG_TYPE(BPF_PROG_TYPE_FLOW_DISSECTOR, flow_dissector)
		#endif
		#ifdef CONFIG_BPF_EVENTS
		BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe)
		@@ -32,7 +33,6 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2)
		#ifdef CONFIG_INET
		BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport)
		#endif
		BPF_PROG_TYPE(BPF_PROG_TYPE_FLOW_DISSECTOR, flow_dissector)

		BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
		BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)

include/linux/skbuff.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -1194,10 +1194,23 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
		const struct flow_dissector_key *key,
		unsigned int key_count);

		#ifdef CONFIG_NET
		int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
		struct bpf_prog *prog);

		int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr);
		#else
		static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
		struct bpf_prog *prog)
		{
		return -EOPNOTSUPP;
		}

		static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
		{
		return -EOPNOTSUPP;
		}
		#endif

		bool __skb_flow_dissect(const struct sk_buff *skb,
		struct flow_dissector *flow_dissector,

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