Re: [PATCH bpf-next 4/4] xdpsock: add an option to create AF_XDP sockets in XDP_DIRECT mode

[Björn Töpel]

On 2019-10-08 08:16, Sridhar Samudrala wrote:

This option enables an AF_XDP socket to bind with a XDP_DIRECT flag
that allows packets received on the associated queue to be received
directly when an XDP program is not attached.

Signed-off-by: Sridhar Samudrala <sridhar.samudr...@intel.com>

Acked-by: Björn Töpel <bjorn.to...@intel.com>

---
  samples/bpf/xdpsock_user.c | 17 +++++++++++++----
  1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index 405c4e091f8b..6f4633769968 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -129,6 +129,9 @@ static void print_benchmark(bool running)
        if (opt_poll)
                printf("poll() ");

+ if (opt_xdp_bind_flags & XDP_DIRECT)

+               printf("direct-xsk ");
+
        if (running) {
                printf("running...");
                fflush(stdout);
@@ -202,7 +205,8 @@ static void int_exit(int sig)
        dump_stats();
        xsk_socket__delete(xsks[0]->xsk);
        (void)xsk_umem__delete(umem);
-       remove_xdp_program();
+       if (!(opt_xdp_bind_flags & XDP_DIRECT))
+               remove_xdp_program();

exit(EXIT_SUCCESS);

  }
@@ -213,7 +217,8 @@ static void __exit_with_error(int error, const char *file, 
const char *func,
        fprintf(stderr, "%s:%s:%i: errno: %d/\"%s\"\n", file, func,
                line, error, strerror(error));
        dump_stats();
-       remove_xdp_program();
+       if (!(opt_xdp_bind_flags & XDP_DIRECT))
+               remove_xdp_program();
        exit(EXIT_FAILURE);
  }

@@ -363,6 +368,7 @@ static struct option long_options[] = {

        {"frame-size", required_argument, 0, 'f'},
        {"no-need-wakeup", no_argument, 0, 'm'},
        {"unaligned", no_argument, 0, 'u'},
+       {"direct-xsk", no_argument, 0, 'd'},
        {0, 0, 0, 0}
  };

@@ -386,6 +392,7 @@ static void usage(const char *prog)

                "  -m, --no-need-wakeup Turn off use of driver need wakeup 
flag.\n"
                "  -f, --frame-size=n   Set the frame size (must be a power of two 
in aligned mode, default is %d).\n"
                "  -u, --unaligned Enable unaligned chunk placement\n"
+               "  -d, --direct-xsk        Direct packets to XDP socket.\n"
                "\n";
        fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE);
        exit(EXIT_FAILURE);
@@ -398,7 +405,7 @@ static void parse_command_line(int argc, char **argv)
        opterr = 0;

for (;;) {

-               c = getopt_long(argc, argv, "Frtli:q:psSNn:czf:mu",
+               c = getopt_long(argc, argv, "Frtli:q:psSNn:czf:mud",
                                long_options, &option_index);
                if (c == -1)
                        break;
@@ -452,7 +459,9 @@ static void parse_command_line(int argc, char **argv)
                        opt_need_wakeup = false;
                        opt_xdp_bind_flags &= ~XDP_USE_NEED_WAKEUP;
                        break;
-
+               case 'd':
+                       opt_xdp_bind_flags |= XDP_DIRECT;
+                       break;
                default:
                        usage(basename(argv[0]));
                }