Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] bpf: fix building without CONFIG_INET | Date | Fri, 5 Oct 2018 18:15:12 +0200 |
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The newly added TCP and UDP handling fails to link when CONFIG_INET is disabled:
net/core/filter.o: In function `sk_lookup': filter.c:(.text+0x7ff8): undefined reference to `tcp_hashinfo' filter.c:(.text+0x7ffc): undefined reference to `tcp_hashinfo' filter.c:(.text+0x8020): undefined reference to `__inet_lookup_established' filter.c:(.text+0x8058): undefined reference to `__inet_lookup_listener' filter.c:(.text+0x8068): undefined reference to `udp_table' filter.c:(.text+0x8070): undefined reference to `udp_table' filter.c:(.text+0x808c): undefined reference to `__udp4_lib_lookup' net/core/filter.o: In function `bpf_sk_release': filter.c:(.text+0x82e8): undefined reference to `sock_gen_put'
The compiler can optimize it out and avoid those references for the most part, but we are missing a few steps here:
- sk_lookup() should always have been marked 'static', this also avoids a warning about a missing prototype when building with 'make W=1'. - The BPF_CALL_x() macro needs a little change to allow marking the unneeded BPF call as 'static' and having the compiler drop them. - The reference to the bpf_func_proto must be made conditional.
Fixes: 6acc9b432e67 ("bpf: Add helper to retrieve socket in BPF") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- include/linux/filter.h | 2 +- net/core/filter.c | 18 +++++++++++------- 2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h index 6791a0ac0139..d9ec9d908bbe 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -428,9 +428,9 @@ struct sock_reuseport; u64, __ur_3, u64, __ur_4, u64, __ur_5) #define BPF_CALL_x(x, name, ...) \ + u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ - u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \ { \ return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ diff --git a/net/core/filter.c b/net/core/filter.c index 30c6b2d3ef16..dd5fe021f44c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4817,7 +4817,7 @@ static const struct bpf_func_proto bpf_lwt_seg6_adjust_srh_proto = { }; #endif /* CONFIG_IPV6_SEG6_BPF */ -struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple, +static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple, struct sk_buff *skb, u8 family, u8 proto) { int dif = skb->dev->ifindex; @@ -4902,13 +4902,13 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, return (unsigned long) sk; } -BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb, +static BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb, struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) { return bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP, netns_id, flags); } -static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = { +static const __maybe_unused struct bpf_func_proto bpf_sk_lookup_tcp_proto = { .func = bpf_sk_lookup_tcp, .gpl_only = false, .pkt_access = true, @@ -4920,13 +4920,13 @@ static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = { .arg5_type = ARG_ANYTHING, }; -BPF_CALL_5(bpf_sk_lookup_udp, struct sk_buff *, skb, +static BPF_CALL_5(bpf_sk_lookup_udp, struct sk_buff *, skb, struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) { return bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP, netns_id, flags); } -static const struct bpf_func_proto bpf_sk_lookup_udp_proto = { +static const __maybe_unused struct bpf_func_proto bpf_sk_lookup_udp_proto = { .func = bpf_sk_lookup_udp, .gpl_only = false, .pkt_access = true, @@ -4938,14 +4938,14 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = { .arg5_type = ARG_ANYTHING, }; -BPF_CALL_1(bpf_sk_release, struct sock *, sk) +static BPF_CALL_1(bpf_sk_release, struct sock *, sk) { if (!sock_flag(sk, SOCK_RCU_FREE)) sock_gen_put(sk); return 0; } -static const struct bpf_func_proto bpf_sk_release_proto = { +static const __maybe_unused struct bpf_func_proto bpf_sk_release_proto = { .func = bpf_sk_release, .gpl_only = false, .ret_type = RET_INTEGER, @@ -5158,12 +5158,14 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_skb_ancestor_cgroup_id: return &bpf_skb_ancestor_cgroup_id_proto; #endif +#ifdef CONFIG_INET case BPF_FUNC_sk_lookup_tcp: return &bpf_sk_lookup_tcp_proto; case BPF_FUNC_sk_lookup_udp: return &bpf_sk_lookup_udp_proto; case BPF_FUNC_sk_release: return &bpf_sk_release_proto; +#endif default: return bpf_base_func_proto(func_id); } @@ -5264,12 +5266,14 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_sk_redirect_hash_proto; case BPF_FUNC_get_local_storage: return &bpf_get_local_storage_proto; +#ifdef CONFIG_INET case BPF_FUNC_sk_lookup_tcp: return &bpf_sk_lookup_tcp_proto; case BPF_FUNC_sk_lookup_udp: return &bpf_sk_lookup_udp_proto; case BPF_FUNC_sk_release: return &bpf_sk_release_proto; +#endif default: return bpf_base_func_proto(func_id); } -- 2.18.0
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