selftests/bpf: Introduce verdict programs for sockmap_redir

Instead of piggybacking on test_sockmap_listen, introduce
test_sockmap_redir especially for sockmap redirection tests.

Suggested-by: Jiayuan Chen <mrpre@163.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20250515-selftests-sockmap-redir-v3-4-a1ea723f7e7e@rbox.co

diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_redir.c b/tools/testing/selftests/bpf/progs/test_sockmap_redir.c
new file mode 100644 (file)
index 0000000..34d9f4f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sockmap_redir.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+SEC(".maps") struct {
+       __uint(type, BPF_MAP_TYPE_SOCKMAP);
+       __uint(max_entries, 1);
+       __type(key, __u32);
+       __type(value, __u64);
+} nop_map, sock_map;
+
+SEC(".maps") struct {
+       __uint(type, BPF_MAP_TYPE_SOCKHASH);
+       __uint(max_entries, 1);
+       __type(key, __u32);
+       __type(value, __u64);
+} nop_hash, sock_hash;
+
+SEC(".maps") struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __uint(max_entries, 2);
+       __type(key, int);
+       __type(value, unsigned int);
+} verdict_map;
+
+/* Set by user space */
+int redirect_type;
+int redirect_flags;
+
+#define redirect_map(__data)                                                   \
+       _Generic((__data),                                                     \
+                struct __sk_buff * : bpf_sk_redirect_map,                     \
+                struct sk_msg_md * : bpf_msg_redirect_map                     \
+       )((__data), &sock_map, (__u32){0}, redirect_flags)
+
+#define redirect_hash(__data)                                                  \
+       _Generic((__data),                                                     \
+                struct __sk_buff * : bpf_sk_redirect_hash,                    \
+                struct sk_msg_md * : bpf_msg_redirect_hash                    \
+       )((__data), &sock_hash, &(__u32){0}, redirect_flags)
+
+#define DEFINE_PROG(__type, __param)                                           \
+SEC("sk_" XSTR(__type))                                                        \
+int prog_ ## __type ## _verdict(__param data)                                  \
+{                                                                              \
+       unsigned int *count;                                                   \
+       int verdict;                                                           \
+                                                                              \
+       if (redirect_type == BPF_MAP_TYPE_SOCKMAP)                             \
+               verdict = redirect_map(data);                                  \
+       else if (redirect_type == BPF_MAP_TYPE_SOCKHASH)                       \
+               verdict = redirect_hash(data);                                 \
+       else                                                                   \
+               verdict = redirect_type - __MAX_BPF_MAP_TYPE;                  \
+                                                                              \
+       count = bpf_map_lookup_elem(&verdict_map, &verdict);                   \
+       if (count)                                                             \
+               (*count)++;                                                    \
+                                                                              \
+       return verdict;                                                        \
+}
+
+DEFINE_PROG(skb, struct __sk_buff *);
+DEFINE_PROG(msg, struct sk_msg_md *);
+
+char _license[] SEC("license") = "GPL";