[PATCH bpf-next v2] selftests/bpf: Fix error: undeclared identifier 'NF_NAT_MANIP_SRC'

[Rong Tao <rtoax@foxmail.com>]

From: Rong Tao <rongtao@cestc.cn>

commit 472caa69183f("netfilter: nat: un-export nf_nat_used_tuple")
introduce NF_NAT_MANIP_SRC/DST enum in include/net/netfilter/nf_nat.h,
and commit b06b45e82b59("selftests/bpf: add tests for bpf_ct_set_nat_info
kfunc") use NF_NAT_MANIP_SRC/DST in test_bpf_nf.c.

In bpf kself-test config (tools/testing/selftests/bpf/config) nf_nat
is compiled as built-in, this issue occurs just if it is compiled as
module. We could use BPF CO-RE and ___suffix rule to avoid this.

How to reproduce the error:

    $ make -C tools/testing/selftests/bpf/
    ...
      CLNG-BPF [test_maps] test_bpf_nf.bpf.o
      error: use of undeclared identifier 'NF_NAT_MANIP_SRC'
            bpf_ct_set_nat_info(ct, &saddr, sport, NF_NAT_MANIP_SRC);
                                                           ^
      error: use of undeclared identifier 'NF_NAT_MANIP_DST'
            bpf_ct_set_nat_info(ct, &daddr, dport, NF_NAT_MANIP_DST);
                                                           ^
    2 errors generated.

Signed-off-by: Rong Tao <rongtao@cestc.cn>
---
v2: use BPF CO-RE and ___suffix rule to avoid this error.
v1: https://lore.kernel.org/lkml/tencent_29D7ABD1744417031AA1B52C914B61158E07@qq.com/
---
 .../testing/selftests/bpf/progs/test_bpf_nf.c | 30 +++++++++++++++++--
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
index 227e85e85dda..1706984e1a6a 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
@@ -2,6 +2,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
+#include <bpf/bpf_core_read.h>
 
 #define EAFNOSUPPORT 97
 #define EPROTO 71
@@ -11,6 +12,11 @@
 
 extern unsigned long CONFIG_HZ __kconfig;
 
+enum nf_nat_manip_type___x {
+	NF_NAT_MANIP_SRC___x,
+	NF_NAT_MANIP_DST___x,
+};
+
 int test_einval_bpf_tuple = 0;
 int test_einval_reserved = 0;
 int test_einval_netns_id = 0;
@@ -58,7 +64,7 @@ int bpf_ct_change_timeout(struct nf_conn *, u32) __ksym;
 int bpf_ct_set_status(struct nf_conn *, u32) __ksym;
 int bpf_ct_change_status(struct nf_conn *, u32) __ksym;
 int bpf_ct_set_nat_info(struct nf_conn *, union nf_inet_addr *,
-			int port, enum nf_nat_manip_type) __ksym;
+			int port, int type) __ksym;
 
 static __always_inline void
 nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
@@ -151,16 +157,34 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple *, u32,
 		union nf_inet_addr saddr = {};
 		union nf_inet_addr daddr = {};
 		struct nf_conn *ct_ins;
+		int manip_src;
+		int manip_dst;
+		enum nf_nat_manip_type___x mapip_type_x;
+
+		if (!bpf_core_type_exists(enum nf_nat_manip_type)) {
+			bpf_printk("enum nf_nat_manip_type not exist.\n");
+			return;
+		}
+
+		if (bpf_core_enum_value_exists(mapip_type_x, NF_NAT_MANIP_SRC___x))
+			manip_src = bpf_core_enum_value(mapip_type_x, NF_NAT_MANIP_SRC___x);
+		else
+			return;
+
+		if (bpf_core_enum_value_exists(mapip_type_x, NF_NAT_MANIP_DST___x))
+			manip_dst = bpf_core_enum_value(mapip_type_x, NF_NAT_MANIP_DST___x);
+		else
+			return;
 
 		bpf_ct_set_timeout(ct, 10000);
 		ct->mark = 77;
 
 		/* snat */
 		saddr.ip = bpf_get_prandom_u32();
-		bpf_ct_set_nat_info(ct, &saddr, sport, NF_NAT_MANIP_SRC);
+		bpf_ct_set_nat_info(ct, &saddr, sport, manip_src);
 		/* dnat */
 		daddr.ip = bpf_get_prandom_u32();
-		bpf_ct_set_nat_info(ct, &daddr, dport, NF_NAT_MANIP_DST);
+		bpf_ct_set_nat_info(ct, &daddr, dport, manip_dst);
 
 		ct_ins = bpf_ct_insert_entry(ct);
 		if (ct_ins) {
-- 
2.31.1