Messages in this thread | | | From | Song Liu <> | Date | Fri, 5 Oct 2018 12:02:48 -0700 | Subject | Re: [PATCH] bpf: fix building without CONFIG_INET |
| |
On Fri, Oct 5, 2018 at 9:18 AM Arnd Bergmann <arnd@arndb.de> wrote: > > 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); > }
BPF_CALL_x() has static already (before this patch). We should not need change that for all the BPF_CALL_?(). Joe's version looks better to me.
Thanks, Song
> > -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 >
| |