Re: [PATCH bpf-next v2 5/9] selftests/bpf: Add selftest for sockmap/hashmap redirection

On Fri, Apr 11, 2025 at 01:32:41PM +0200, Michal Luczaj wrote:

+static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,

• 		 int sd_in, int sd_out, int sd_recv,
  

• 		 struct maps *maps, int status)
  

+{

• unsigned int drop, pass;
• char *send_buf = "ab";
• char recv_buf = '\0';
• ssize_t n, len = 1;
• /* Zero out the verdict map */
• if (xbpf_map_update_elem(maps->verd, &u32(SK_DROP), &u32(0), BPF_ANY) ||

•    xbpf_map_update_elem(maps->verd, &u32(SK_PASS), &u32(0), BPF_ANY))
  

• return;
  

• if (xbpf_map_update_elem(maps->in, &u32(0), &u64(sd_in), BPF_NOEXIST))

• return;
  

• if (xbpf_map_update_elem(maps->out, &u32(0), &u64(sd_out), BPF_NOEXIST))

• goto del_in;
  

• /* Last byte is OOB data when send_flags has MSG_OOB bit set */
• if (send_flags & MSG_OOB)

• len++;
  

• n = send(sd_send, send_buf, len, send_flags);
• if (n >= 0 && n < len)

• FAIL("incomplete send");
  

• if (n < 0) {

• /* sk_msg redirect combo not supported? */
  

• if (status & SUPPORTED || errno != EACCES)
  

• 	FAIL_ERRNO("send");
  

• goto out;
  

• }
• if (!(status & SUPPORTED)) {

• handle_unsupported(sd_send, sd_peer, sd_in, sd_out, sd_recv,
  

• 		   maps->verd, status);
  

• goto out;
  

• }
• errno = 0;
• n = recv_timeout(sd_recv, &recv_buf, 1, 0, IO_TIMEOUT_SEC);
• if (n != 1) {

• FAIL_ERRNO("recv_timeout()");
  

• goto out;
  

• }

I prefer multiple send and receive operations, or implementing a loop at the outer level.

Thanks.