[PATCH -next] bpf: fix net/core/filter build errors when INET is not enabled

[Randy Dunlap]

From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Fix build errors when CONFIG_INET is not set/enabled.

(.text+0x2b1b): undefined reference to `tcp_prot'
(.text+0x2b3b): undefined reference to `tcp_prot'

Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Martin KaFai Lau <kafai@xxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: Andrii Nakryiko <andriin@xxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: KP Singh <kpsingh@xxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: bpf@xxxxxxxxxxxxxxx
---
 net/core/filter.c |    4 ++++
 1 file changed, 4 insertions(+)

--- linux-next-20200630.orig/net/core/filter.c
+++ linux-next-20200630/net/core/filter.c
@@ -9328,8 +9328,10 @@ const struct bpf_func_proto bpf_skc_to_t
 
 BPF_CALL_1(bpf_skc_to_tcp_timewait_sock, struct sock *, sk)
 {
+#ifdef CONFIG_INET
 	if (sk->sk_prot == &tcp_prot && sk->sk_state == TCP_TIME_WAIT)
 		return (unsigned long)sk;
+#endif
 
 #if IS_BUILTIN(CONFIG_IPV6)
 	if (sk->sk_prot == &tcpv6_prot && sk->sk_state == TCP_TIME_WAIT)
@@ -9350,8 +9352,10 @@ const struct bpf_func_proto bpf_skc_to_t
 
 BPF_CALL_1(bpf_skc_to_tcp_request_sock, struct sock *, sk)
 {
+#ifdef CONFIG_INET
 	if (sk->sk_prot == &tcp_prot  && sk->sk_state == TCP_NEW_SYN_RECV)
 		return (unsigned long)sk;
+#endif
 
 #if IS_BUILTIN(CONFIG_IPV6)
 	if (sk->sk_prot == &tcpv6_prot && sk->sk_state == TCP_NEW_SYN_RECV)