Re: [PATCH bpf] selftests/bpf: Fix xdp_synproxy build failure if CONFIG_NF_CONNTRACK=m/n

On Fri, Jul 8, 2022 at 6:03 AM Maxim Mikityanskiy maximmi@nvidia.com wrote:

When CONFIG_NF_CONNTRACK=m, struct bpf_ct_opts and enum member BPF_F_CURRENT_NETNS are not exposed. This commit allows building the xdp_synproxy selftest in such cases. Note that nf_conntrack must be loaded before running the test if it's compiled as a module.

This commit also allows this selftest to be successfully compiled when CONFIG_NF_CONNTRACK is disabled.

One unused local variable of type struct bpf_ct_opts is also removed.

Reported-by: Yauheni Kaliuta ykaliuta@redhat.com Signed-off-by: Maxim Mikityanskiy maximmi@nvidia.com Fixes: fb5cd0ce70d4 ("selftests/bpf: Add selftests for raw syncookie helpers")

Given tools/testing/selftests/bpf/config specifies CONFIG_NF_CONNTRACK=y, I don't think this is really necessary.

Thanks, Song

---

.../selftests/bpf/progs/xdp_synproxy_kern.c | 24 +++++++++++++------ 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c index 9fd62e94b5e6..736686e903f6 100644 --- a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c +++ b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c @@ -77,16 +77,30 @@ struct { __uint(max_entries, MAX_ALLOWED_PORTS); } allowed_ports SEC(".maps");

+/* Some symbols defined in net/netfilter/nf_conntrack_bpf.c are unavailable in

• • vmlinux.h if CONFIG_NF_CONNTRACK=m, so they are redefined locally.
• */

+struct bpf_ct_opts___local {

•   s32 netns_id;
  

•   s32 error;
  

•   u8 l4proto;
  

•   u8 dir;
  

•   u8 reserved[2];
  

+} __attribute__((preserve_access_index));

+#define BPF_F_CURRENT_NETNS (-1)

extern struct nf_conn *bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple, __u32 len_tuple,

•                                    struct bpf_ct_opts *opts,
  

•                                    struct bpf_ct_opts___local *opts,
                                     __u32 len_opts) __ksym;
  
  

extern struct nf_conn *bpf_skb_ct_lookup(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple, u32 len_tuple,

•                                    struct bpf_ct_opts *opts,
  

•                                    struct bpf_ct_opts___local *opts,
                                     u32 len_opts) __ksym;
  
  

extern void bpf_ct_release(struct nf_conn *ct) __ksym; @@ -393,7 +407,7 @@ static __always_inline int tcp_dissect(void *data, void *data_end,

static __always_inline int tcp_lookup(void *ctx, struct header_pointers *hdr, bool xdp) {

•   struct bpf_ct_opts ct_lookup_opts = {
  

•   struct bpf_ct_opts___local ct_lookup_opts = {
            .netns_id = BPF_F_CURRENT_NETNS,
            .l4proto = IPPROTO_TCP,
    };
  

@@ -714,10 +728,6 @@ static __always_inline int syncookie_handle_ack(struct header_pointers *hdr) static __always_inline int syncookie_part1(void *ctx, void *data, void *data_end, struct header_pointers *hdr, bool xdp) {

•   struct bpf_ct_opts ct_lookup_opts = {
  

•           .netns_id = BPF_F_CURRENT_NETNS,
  

•           .l4proto = IPPROTO_TCP,
  

•   };
    int ret;
  
    ret = tcp_dissect(data, data_end, hdr);
  

-- 2.30.2