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bpf, samples: Fix xdpsock with '-M' parameter missing unload process 

Execute the following command and exit, then execute it again, the following
error will be reported:

  $ sudo ./samples/bpf/xdpsock -i ens4f2 -M
  ^C
  $ sudo ./samples/bpf/xdpsock -i ens4f2 -M
  libbpf: elf: skipping unrecognized data section(16) .eh_frame
  libbpf: elf: skipping relo section(17) .rel.eh_frame for section(16) .eh_frame
  libbpf: Kernel error message: XDP program already attached
  ERROR: link set xdp fd failed

Commit c9d27c9e8d ("samples: bpf: Do not unload prog within xdpsock") removed
the unloading prog code because of the presence of bpf_link. This is fine if
XDP_SHARED_UMEM is disabled, but if it is enabled, unloading the prog is still
needed.

Fixes: c9d27c9e8d ("samples: bpf: Do not unload prog within xdpsock")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Cc: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20210628091815.2373487-1-wanghai38@huawei.com
This commit is contained in:
Wang Hai 2021-06-28 17:18:15 +08:00 committed by Daniel Borkmann
parent 5a0ae9872d
commit 2620e92ae6
1 changed files with 28 additions and 0 deletions
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28
samples/bpf/xdpsock_user.c
View File

@ -96,6 +96,7 @@ static int opt_xsk_frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
static int opt_timeout = 1000;
static bool opt_need_wakeup = true;
static u32 opt_num_xsks = 1;
static u32 prog_id;
static bool opt_busy_poll;
static bool opt_reduced_cap;
@ -461,6 +462,23 @@ static void *poller(void *arg)
return NULL;
}
static void remove_xdp_program(void)
{
u32 curr_prog_id = 0;
if (bpf_get_link_xdp_id(opt_ifindex, &curr_prog_id, opt_xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(EXIT_FAILURE);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(opt_ifindex, -1, opt_xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on a given interface\n");
else
printf("program on interface changed, not removing\n");
}
static void int_exit(int sig)
{
benchmark_done = true;
@ -471,6 +489,9 @@ 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));
if (opt_num_xsks > 1)
remove_xdp_program();
exit(EXIT_FAILURE);
}
@ -490,6 +511,9 @@ static void xdpsock_cleanup(void)
if (write(sock, &cmd, sizeof(int)) < 0)
exit_with_error(errno);
}
if (opt_num_xsks > 1)
remove_xdp_program();
}
static void swap_mac_addresses(void *data)
@ -857,6 +881,10 @@ static struct xsk_socket_info *xsk_configure_socket(struct xsk_umem_info *umem,
if (ret)
exit_with_error(-ret);
ret = bpf_get_link_xdp_id(opt_ifindex, &prog_id, opt_xdp_flags);
if (ret)
exit_with_error(-ret);
xsk->app_stats.rx_empty_polls = 0;
xsk->app_stats.fill_fail_polls = 0;
xsk->app_stats.copy_tx_sendtos = 0;