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samples/bpf: Check detach prog exist or not in xdp_fwd

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Before detach the prog, we should check detach prog exist or not.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20220606005425.261967-1-shaozhengchao@huawei.com
This commit is contained in:
Zhengchao Shao 2022-06-06 08:54:25 +08:00 committed by Andrii Nakryiko
parent 3831cd1f9f
commit de5bb43826
1 changed files with 49 additions and 6 deletions
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55
samples/bpf/xdp_fwd_user.c
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@ -47,17 +47,60 @@ static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
return err;
}
static int do_detach(int idx, const char *name)
static int do_detach(int ifindex, const char *ifname, const char *app_name)
{
int err;
LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
struct bpf_prog_info prog_info = {};
char prog_name[BPF_OBJ_NAME_LEN];
__u32 info_len, curr_prog_id;
int prog_fd;
int err = 1;
err = bpf_xdp_detach(idx, xdp_flags, NULL);
if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) {
printf("ERROR: bpf_xdp_query_id failed (%s)\n",
strerror(errno));
return err;
}
if (!curr_prog_id) {
printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n",
xdp_flags, ifname);
return err;
}
info_len = sizeof(prog_info);
prog_fd = bpf_prog_get_fd_by_id(curr_prog_id);
if (prog_fd < 0) {
printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n",
strerror(errno));
return prog_fd;
}
err = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &info_len);
if (err) {
printf("ERROR: bpf_obj_get_info_by_fd failed (%s)\n",
strerror(errno));
goto close_out;
}
snprintf(prog_name, sizeof(prog_name), "%s_prog", app_name);
prog_name[BPF_OBJ_NAME_LEN - 1] = '\0';
if (strcmp(prog_info.name, prog_name)) {
printf("ERROR: %s isn't attached to %s\n", app_name, ifname);
err = 1;
goto close_out;
}
opts.old_prog_fd = prog_fd;
err = bpf_xdp_detach(ifindex, xdp_flags, &opts);
if (err < 0)
printf("ERROR: failed to detach program from %s\n", name);
printf("ERROR: failed to detach program from %s (%s)\n",
ifname, strerror(errno));
/* TODO: Remember to cleanup map, when adding use of shared map
* bpf_map_delete_elem((map_fd, &idx);
*/
close_out:
close(prog_fd);
return err;
}
@ -169,7 +212,7 @@ int main(int argc, char **argv)
return 1;
}
if (!attach) {
err = do_detach(idx, argv[i]);
err = do_detach(idx, argv[i], prog_name);
if (err)
ret = err;
} else {