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Message-Id: <20181005161526.843924-1-arnd@arndb.de>
Date: Fri, 5 Oct 2018 18:15:12 +0200
From: Arnd Bergmann <arnd@...db.de>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
"David S. Miller" <davem@...emloft.net>
Cc: Arnd Bergmann <arnd@...db.de>,
John Fastabend <john.fastabend@...il.com>,
Martin KaFai Lau <kafai@...com>,
Toshiaki Makita <makita.toshiaki@....ntt.co.jp>,
Lawrence Brakmo <brakmo@...com>, Andrey Ignatov <rdna@...com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Jakub Kicinski <jakub.kicinski@...ronome.com>,
Mathieu Xhonneux <m.xhonneux@...il.com>,
David Ahern <dsahern@...il.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] bpf: fix building without CONFIG_INET
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@...db.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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