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SubjectRe: [PATCH bpf-next] selftests/bpf: Fix undeclared identifier build errors of test_bpf_nf.c
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On 01/18/2023 02:29 AM, Yonghong Song wrote:
>
>
> On 1/17/23 1:52 AM, Tiezhu Yang wrote:
>>
>>
>> On 01/17/2023 02:48 PM, Yonghong Song wrote:
>>>
>>>
>>> On 1/16/23 5:54 AM, Alan Maguire wrote:
>>>> On 16/01/2023 12:30, Eduard Zingerman wrote:
>>>>> On Mon, 2023-01-16 at 12:55 +0800, Tiezhu Yang wrote:
>>>>>> $ make -C tools/testing/selftests/bpf/
>>>>>>
>>>>>> CLNG-BPF [test_maps] test_bpf_nf.bpf.o
>>>>>> progs/test_bpf_nf.c:160:42: error: use of undeclared identifier
>>>>>> 'NF_NAT_MANIP_SRC'
>>>>>> bpf_ct_set_nat_info(ct, &saddr, sport,
>>>>>> NF_NAT_MANIP_SRC);
>>>>>> ^
>>>>>> progs/test_bpf_nf.c:163:42: error: use of undeclared identifier
>>>>>> 'NF_NAT_MANIP_DST'
>>>>>> bpf_ct_set_nat_info(ct, &daddr, dport,
>>>>>> NF_NAT_MANIP_DST);
>>>>>> ^
>>>>>> 2 errors generated.
>>>>>>
>>>>>> Copy the definitions in include/net/netfilter/nf_nat.h to
>>>>>> test_bpf_nf.c
>>>>>> to fix the above build errors.
>>>>>>
>>>>>> Fixes: b06b45e82b59 ("selftests/bpf: add tests for
>>>>>> bpf_ct_set_nat_info kfunc")
>>>>>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>>>>>> ---
>>>>>> tools/testing/selftests/bpf/progs/test_bpf_nf.c | 5 +++++
>>>>>> 1 file changed, 5 insertions(+)
>>>>>>
>>>>>> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>>>>>> b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>>>>>> index 227e85e..114f961 100644
>>>>>> --- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>>>>>> +++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>>>>>> @@ -34,6 +34,11 @@ __be16 dport = 0;
>>>>>> int test_exist_lookup = -ENOENT;
>>>>>> u32 test_exist_lookup_mark = 0;
>>>>>> +enum nf_nat_manip_type {
>>>>>> + NF_NAT_MANIP_SRC,
>>>>>> + NF_NAT_MANIP_DST
>>>>>> +};
>>>>>> +
>>>>>
>>>>> This is confusing, when I build the kernel/tests I get the declaration
>>>>> the "enum nf_nat_manip_type" from the vmlinux.h (which is included
>>>>> from test_bpf_nf.c).
>>>>> Which means that this patch results in compilation error with my
>>>>> configuration.
>>>>> Is there a chance that your kernel is configured without some
>>>>> necessary netfilter
>>>>> configuration options? Have you tried this patch with BPF CI?
>>>>>
>>>>
>>>> Yep; I suspect if CONFIG_NF_NAT=m , the required definitions won't
>>>> make it
>>>> into vmlinux.h. The reference tools/testing/seftests/bpf/config has
>>>> CONFIG_NF_NAT=y so it is at least documented in the referenced config.
>>>>
>>>> I'd suggest going the route of
>>>>
>>>> commit aa67961f3243dfff26c47769f87b4d94b07ec71f
>>>> Author: Martin KaFai Lau <martin.lau@kernel.org>
>>>> Date: Tue Dec 6 11:35:54 2022 -0800
>>>>
>>>> selftests/bpf: Allow building bpf tests with
>>>> CONFIG_XFRM_INTERFACE=[m|n]
>>>> ...and adding/using local definitons like:
>>>>
>>>> enum nf_nat_manip_type_local {
>>>> NF_NAT_MANIP_SRC_LOCAL,
>>>> NF_NAT_MANIP_DST_LOCAL
>>>> };
>>>
>>> The above won't support core, and since preserve_access_index attribute
>>> does not support enum for now. We need to use bpf_core_enum_value to
>>> retrieve the proper value through CORE.
>>>
>>> could you try the following?
>>>
>>> enum nf_nat_manip_type___local {
>>> NF_NAT_MANIP_SRC___LOCAL,
>>> NF_NAT_MANIP_DST___LOCAL,
>>> };
>>
>> This is OK, it is similar with commit 1058b6a78db2 ("selftests/bpf: Do
>> not fail build if CONFIG_NF_CONNTRACK=m/n").
>>
>>>
>>> ...
>>> bpf_ct_set_nat_info(ct, &saddr, sport, bpf_core_enum_value(enum
>>> nf_nat_manip_type___local, NF_NAT_MANIP_SRC___LOCAL));
>>> ...
>>>
>>> bpf_ct_set_nat_info(ct, &daddr, dport, bpf_core_enum_value(enum
>>> nf_nat_manip_type___local, NF_NAT_MANIP_DST___LOCAL));
>>>
>>> whether it works or not? Could you also try if the
>>> enumerator sequence in enum nf_nat_manip_type___local changed?
>>>
>>>>
>>>> ...to avoid the name clash.
>>>>
>>>>
>>>> Alan
>>
>> I tested this on x86_64 fedora 36, using config-5.17.5-300.fc36.x86_64
>> to generate .config, CONFIG_NF_CONNTRACK=m, CONFIG_NF_NAT=m, there are
>> no definitions of NF_NAT_MANIP_SRC and NF_NAT_MANIP_DST in vmlinux.h,
>> build test_bpf_nf.c failed.
>
> Thanks for trying. Yes, I tried in my environment and it failed because
> I didn't change the enum nf_nat_manip_type type for kfunc:
> int bpf_ct_set_nat_info(struct nf_conn *, union nf_inet_addr *,
> int port, enum nf_nat_manip_type) __ksym;
>
> But when I changed 'enum nf_nat_manip_type' to
> 'enum nf_nat_manip_type___local', kernel complains kfunc argument
> mismatch. The reason most likely is 'enum nf_nat_manip_type___local'
> is not converted to 'enum nf_nat_manip_type' by libbpf.
>
> This might be expected as preserve_access_index attribute only
> supports record (struct/union) type and libbpf might just do that.
> Could you double check whether this is the case or not?
>
> Maybe it is time to implement preserve_access_index support
> for enum type in clang now.
>
> But we need to resolve the issue, even temporarily for now.
> See below.
>
>>
>> $ grep -w CONFIG_NF_CONNTRACK /boot/config-5.17.5-300.fc36.x86_64
>> CONFIG_NF_CONNTRACK=m
>> $ grep -w CONFIG_NF_NAT /boot/config-5.17.5-300.fc36.x86_64
>> CONFIG_NF_NAT=m
>>
>> I tested with various configs, the definitions of NF_NAT_MANIP_SRC and
>> NF_NAT_MANIP_DST in vmlinux.h only depend on CONFIG_NF_CONNTRACK=y.
>>
>> (1) CONFIG_NF_CONNTRACK=m, CONFIG_NF_NAT=m, no definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> CONFIG_NF_CONNTRACK=m
>> $ grep -w CONFIG_NF_NAT .config
>> CONFIG_NF_NAT=m
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $
>>
>> (2) CONFIG_NF_CONNTRACK=m, CONFIG_NF_NAT=y, no definitions
>> This case is unable, because CONFIG_NF_NAT depends on
>> CONFIG_NF_CONNTRACK.
>>
>> (3) CONFIG_NF_CONNTRACK=m, CONFIG_NF_NAT=n, no definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> CONFIG_NF_CONNTRACK=m
>> $ grep -w CONFIG_NF_NAT .config
>> # CONFIG_NF_NAT is not set
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $
>>
>> (4) CONFIG_NF_CONNTRACK=y, CONFIG_NF_NAT=m, have definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> CONFIG_NF_CONNTRACK=y
>> $ grep -w CONFIG_NF_NAT .config
>> CONFIG_NF_NAT=m
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_SRC = 0,
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_DST = 1,
>>
>> (5) CONFIG_NF_CONNTRACK=y, CONFIG_NF_NAT=y, have definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> CONFIG_NF_CONNTRACK=y
>> $ grep -w CONFIG_NF_NAT .config
>> CONFIG_NF_NAT=y
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_SRC = 0,
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_DST = 1,
>>
>> (6) CONFIG_NF_CONNTRACK=y, CONFIG_NF_NAT=n, have definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> CONFIG_NF_CONNTRACK=y
>> $ grep -w CONFIG_NF_NAT .config
>> # CONFIG_NF_NAT is not set
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_SRC = 0,
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> NF_NAT_MANIP_DST = 1,
>>
>> (7) CONFIG_NF_CONNTRACK=n, CONFIG_NF_NAT=n, no definitions
>> $ grep -w CONFIG_NF_CONNTRACK .config
>> # CONFIG_NF_CONNTRACK is not set
>> $ grep -w CONFIG_NF_NAT .config
>> $ grep NF_NAT_MANIP_SRC
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $ grep NF_NAT_MANIP_DST
>> tools/testing/selftests/bpf/tools/include/vmlinux.h
>> $
>>
>> (8) CONFIG_NF_CONNTRACK=n, CONFIG_NF_NAT=y, no definitions
>> This case is unable, because CONFIG_NF_NAT depends on
>> CONFIG_NF_CONNTRACK.
>>
>> Here is an alternative change to check whether CONFIG_NF_CONNTRACK
>> is m, enum nf_nat_manip_type___local is simple, which one is better?
>>
>> $ git diff tools/testing/selftests/bpf/
>> diff --git a/tools/testing/selftests/bpf/Makefile
>> b/tools/testing/selftests/bpf/Makefile
>> index 22533a18705e..f3cf02046c20 100644
>> --- a/tools/testing/selftests/bpf/Makefile
>> +++ b/tools/testing/selftests/bpf/Makefile
>> @@ -325,7 +325,7 @@ endif
>>
>> CLANG_SYS_INCLUDES = $(call
>> get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
>> BPF_CFLAGS = -g -Werror -D__TARGET_ARCH_$(SRCARCH)
>> $(MENDIAN) \
>> - -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) \
>> + -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) -I$(TOOLSINCDIR) \
>> -I$(abspath $(OUTPUT)/../usr/include)
>>
>> CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \
>> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>> b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
>> index 227e85e85dda..f2101807072f 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 <linux/kconfig.h>
>>
>> #define EAFNOSUPPORT 97
>> #define EPROTO 71
>> @@ -34,6 +35,13 @@ __be16 dport = 0;
>> int test_exist_lookup = -ENOENT;
>> u32 test_exist_lookup_mark = 0;
>>
>> +#if IS_MODULE(CONFIG_NF_CONNTRACK)
>> +enum nf_nat_manip_type {
>> + NF_NAT_MANIP_SRC,
>> + NF_NAT_MANIP_DST
>> +};
>> +#endif
>> +
>
> The above change does not work for me. The complication failed with
>
> CLNG-BPF [test_maps]
> btf__core_reloc_nesting___err_missing_container.bpf.o
> CLNG-BPF [test_maps] test_sysctl_loop2.bpf.o
> progs/test_bpf_nf.c:168:42: error: use of undeclared identifier
> 'NF_NAT_MANIP_SRC'
> bpf_ct_set_nat_info(ct, &saddr, sport, NF_NAT_MANIP_SRC);
> ^
> progs/test_bpf_nf.c:171:42: error: use of undeclared identifier
> 'NF_NAT_MANIP_DST'
> bpf_ct_set_nat_info(ct, &daddr, dport, NF_NAT_MANIP_DST);
> ^
> 2 errors generated.
>
>
> Apparently, IS_MODULE(...) is recognized but it returns 0.
> I do have CONFIG_NF_CONNTRACK=m in my config.
> Note that I build the kernel with KBUILD_OUTPUT=<another dir>
> (make -j LLVM=1) so vmlinux is in a different place.
> While I build selftest
> with 'make -C tools/testing/selftests/bpf -j LLVM=1' which
> is in-tree.
>
>> struct nf_conn;
>>
>> struct bpf_ct_opts___local {
>>
>> Note that when unset CONFIG_NF_CONNTRACK, there are much more
>> build errors, I do not know whether it is necessary to fix it
>> and how to fix it properly. Here, I only consider the failed
>> case CONFIG_NF_CONNTRACK=m.
>>
>> Thanks,
>> Tiezhu
>>

I have the following test environment:

system: x86_64 fedora 36
kernel: the latest bpf-next
clang: version 14.0.5 (Fedora 14.0.5-1.fc36)
gcc: 12.2.1 20220819 (Red Hat 12.2.1-2)

With the following changes, there are no any build errors and
warnings if
(1) CONFIG_NF_CONNTRACK=m, CONFIG_NF_NAT=m
(2) CONFIG_NF_CONNTRACK=y, CONFIG_NF_NAT=m
(3) CONFIG_NF_CONNTRACK=y, CONFIG_NF_NAT=y

$ git diff
diff --git a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
index 227e85e85dda..9fc603c9d673 100644
--- a/tools/testing/selftests/bpf/progs/test_bpf_nf.c
+++ b/tools/testing/selftests/bpf/progs/test_bpf_nf.c
@@ -34,6 +34,11 @@ __be16 dport = 0;
int test_exist_lookup = -ENOENT;
u32 test_exist_lookup_mark = 0;

+enum nf_nat_manip_type___local {
+ NF_NAT_MANIP_SRC___local,
+ NF_NAT_MANIP_DST___local
+};
+
struct nf_conn;

struct bpf_ct_opts___local {
@@ -58,7 +63,7 @@ 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, enum nf_nat_manip_type___local) __ksym;

static __always_inline void
nf_ct_test(struct nf_conn *(*lookup_fn)(void *, struct bpf_sock_tuple
*, u32,
@@ -157,10 +162,10 @@ nf_ct_test(struct nf_conn *(*lookup_fn)(void *,
struct bpf_sock_tuple *, u32,

/* 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,
NF_NAT_MANIP_SRC___local);
/* 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,
NF_NAT_MANIP_DST___local);

ct_ins = bpf_ct_insert_entry(ct);
if (ct_ins) {
I will send it as a normal patch for your review, let us see what is
the status of BPF CI.

Thanks,
Tiezhu

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