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-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-link.rst8
-rw-r--r--tools/bpf/bpftool/bash-completion/bpftool4
-rw-r--r--tools/bpf/bpftool/link.c37
-rw-r--r--tools/include/uapi/linux/bpf.h5
-rw-r--r--tools/lib/bpf/bpf.c10
-rw-r--r--tools/lib/bpf/bpf.h2
-rw-r--r--tools/lib/bpf/libbpf.c5
-rw-r--r--tools/lib/bpf/libbpf.h1
-rw-r--r--tools/lib/bpf/libbpf.map2
-rw-r--r--tools/testing/selftests/bpf/prog_tests/cgroup_link.c20
-rw-r--r--tools/testing/selftests/bpf/prog_tests/sk_lookup.c51
-rw-r--r--tools/testing/selftests/bpf/prog_tests/xdp_link.c14
-rw-r--r--tools/testing/selftests/bpf/testing_helpers.c14
-rw-r--r--tools/testing/selftests/bpf/testing_helpers.h3
14 files changed, 144 insertions, 32 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-link.rst b/tools/bpf/bpftool/Documentation/bpftool-link.rst
index 38b0949a185b..4a52e7a93339 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-link.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-link.rst
@@ -21,6 +21,7 @@ LINK COMMANDS
| **bpftool** **link { show | list }** [*LINK*]
| **bpftool** **link pin** *LINK* *FILE*
+| **bpftool** **link detach *LINK*
| **bpftool** **link help**
|
| *LINK* := { **id** *LINK_ID* | **pinned** *FILE* }
@@ -49,6 +50,13 @@ DESCRIPTION
contain a dot character ('.'), which is reserved for future
extensions of *bpffs*.
+ **bpftool link detach** *LINK*
+ Force-detach link *LINK*. BPF link and its underlying BPF
+ program will stay valid, but they will be detached from the
+ respective BPF hook and BPF link will transition into
+ a defunct state until last open file descriptor for that
+ link is closed.
+
**bpftool link help**
Print short help message.
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 257fa310ea2b..f53ed2f1a4aa 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -1122,7 +1122,7 @@ _bpftool()
;;
link)
case $command in
- show|list|pin)
+ show|list|pin|detach)
case $prev in
id)
_bpftool_get_link_ids
@@ -1139,7 +1139,7 @@ _bpftool()
COMPREPLY=( $( compgen -W "$LINK_TYPE" -- "$cur" ) )
return 0
;;
- pin)
+ pin|detach)
if [[ $prev == "$command" ]]; then
COMPREPLY=( $( compgen -W "$LINK_TYPE" -- "$cur" ) )
else
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index 326b8fdf0243..1b793759170e 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -22,6 +22,8 @@ static const char * const link_type_name[] = {
static int link_parse_fd(int *argc, char ***argv)
{
+ int fd;
+
if (is_prefix(**argv, "id")) {
unsigned int id;
char *endptr;
@@ -35,7 +37,10 @@ static int link_parse_fd(int *argc, char ***argv)
}
NEXT_ARGP();
- return bpf_link_get_fd_by_id(id);
+ fd = bpf_link_get_fd_by_id(id);
+ if (fd < 0)
+ p_err("failed to get link with ID %d: %s", id, strerror(errno));
+ return fd;
} else if (is_prefix(**argv, "pinned")) {
char *path;
@@ -316,6 +321,34 @@ static int do_pin(int argc, char **argv)
return err;
}
+static int do_detach(int argc, char **argv)
+{
+ int err, fd;
+
+ if (argc != 2) {
+ p_err("link specifier is invalid or missing\n");
+ return 1;
+ }
+
+ fd = link_parse_fd(&argc, &argv);
+ if (fd < 0)
+ return 1;
+
+ err = bpf_link_detach(fd);
+ if (err)
+ err = -errno;
+ close(fd);
+ if (err) {
+ p_err("failed link detach: %s", strerror(-err));
+ return 1;
+ }
+
+ if (json_output)
+ jsonw_null(json_wtr);
+
+ return 0;
+}
+
static int do_help(int argc, char **argv)
{
if (json_output) {
@@ -326,6 +359,7 @@ static int do_help(int argc, char **argv)
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [LINK]\n"
" %1$s %2$s pin LINK FILE\n"
+ " %1$s %2$s detach LINK\n"
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_LINK "\n"
@@ -341,6 +375,7 @@ static const struct cmd cmds[] = {
{ "list", do_show },
{ "help", do_help },
{ "pin", do_pin },
+ { "detach", do_detach },
{ 0 }
};
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index eb5e0c38eb2c..b134e679e9db 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -117,6 +117,7 @@ enum bpf_cmd {
BPF_LINK_GET_NEXT_ID,
BPF_ENABLE_STATS,
BPF_ITER_CREATE,
+ BPF_LINK_DETACH,
};
enum bpf_map_type {
@@ -634,6 +635,10 @@ union bpf_attr {
__u32 old_prog_fd;
} link_update;
+ struct {
+ __u32 link_fd;
+ } link_detach;
+
struct { /* struct used by BPF_ENABLE_STATS command */
__u32 type;
} enable_stats;
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index e1bdf214f75f..eab14c97c15d 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -603,6 +603,16 @@ int bpf_link_create(int prog_fd, int target_fd,
return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
}
+int bpf_link_detach(int link_fd)
+{
+ union bpf_attr attr;
+
+ memset(&attr, 0, sizeof(attr));
+ attr.link_detach.link_fd = link_fd;
+
+ return sys_bpf(BPF_LINK_DETACH, &attr, sizeof(attr));
+}
+
int bpf_link_update(int link_fd, int new_prog_fd,
const struct bpf_link_update_opts *opts)
{
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 6d367e01d05e..28855fd5b5f4 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -178,6 +178,8 @@ LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
enum bpf_attach_type attach_type,
const struct bpf_link_create_opts *opts);
+LIBBPF_API int bpf_link_detach(int link_fd);
+
struct bpf_link_update_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
__u32 flags; /* extra flags */
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b9f11f854985..7be04e45d29c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7748,6 +7748,11 @@ struct bpf_link *bpf_link__open(const char *path)
return link;
}
+int bpf_link__detach(struct bpf_link *link)
+{
+ return bpf_link_detach(link->fd) ? -errno : 0;
+}
+
int bpf_link__pin(struct bpf_link *link, const char *path)
{
int err;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 9924385462ab..3ed1399bfbbc 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -229,6 +229,7 @@ LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
LIBBPF_API int bpf_link__update_program(struct bpf_link *link,
struct bpf_program *prog);
LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
+LIBBPF_API int bpf_link__detach(struct bpf_link *link);
LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
LIBBPF_API struct bpf_link *
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index ca49a6a7e5b2..099863411f7d 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -273,6 +273,8 @@ LIBBPF_0.0.9 {
LIBBPF_0.1.0 {
global:
+ bpf_link__detach;
+ bpf_link_detach;
bpf_map__ifindex;
bpf_map__key_size;
bpf_map__map_flags;
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_link.c b/tools/testing/selftests/bpf/prog_tests/cgroup_link.c
index 6e04f8d1d15b..4d9b514b3fd9 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_link.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_link.c
@@ -2,6 +2,7 @@
#include <test_progs.h>
#include "cgroup_helpers.h"
+#include "testing_helpers.h"
#include "test_cgroup_link.skel.h"
static __u32 duration = 0;
@@ -37,7 +38,8 @@ void test_cgroup_link(void)
int last_cg = ARRAY_SIZE(cgs) - 1, cg_nr = ARRAY_SIZE(cgs);
DECLARE_LIBBPF_OPTS(bpf_link_update_opts, link_upd_opts);
struct bpf_link *links[ARRAY_SIZE(cgs)] = {}, *tmp_link;
- __u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags;
+ __u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags, prog_id;
+ struct bpf_link_info info;
int i = 0, err, prog_fd;
bool detach_legacy = false;
@@ -219,6 +221,22 @@ void test_cgroup_link(void)
/* BPF programs should still get called */
ping_and_check(0, cg_nr);
+ prog_id = link_info_prog_id(links[0], &info);
+ CHECK(prog_id == 0, "link_info", "failed\n");
+ CHECK(info.cgroup.cgroup_id == 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
+
+ err = bpf_link__detach(links[0]);
+ if (CHECK(err, "link_detach", "failed %d\n", err))
+ goto cleanup;
+
+ /* cgroup_id should be zero in link_info */
+ prog_id = link_info_prog_id(links[0], &info);
+ CHECK(prog_id == 0, "link_info", "failed\n");
+ CHECK(info.cgroup.cgroup_id != 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
+
+ /* First BPF program shouldn't be called anymore */
+ ping_and_check(0, cg_nr - 1);
+
/* leave cgroup and remove them, don't detach programs */
cleanup_cgroup_environment();
diff --git a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
index 379da6f10ee9..c571584c00f5 100644
--- a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
+++ b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c
@@ -34,6 +34,7 @@
#include "bpf_util.h"
#include "cgroup_helpers.h"
#include "network_helpers.h"
+#include "testing_helpers.h"
#include "test_sk_lookup.skel.h"
/* External (address, port) pairs the client sends packets to. */
@@ -469,34 +470,10 @@ static int update_lookup_map(struct bpf_map *map, int index, int sock_fd)
return 0;
}
-static __u32 link_info_prog_id(struct bpf_link *link)
-{
- struct bpf_link_info info = {};
- __u32 info_len = sizeof(info);
- int link_fd, err;
-
- link_fd = bpf_link__fd(link);
- if (CHECK(link_fd < 0, "bpf_link__fd", "failed\n")) {
- errno = -link_fd;
- log_err("bpf_link__fd failed");
- return 0;
- }
-
- err = bpf_obj_get_info_by_fd(link_fd, &info, &info_len);
- if (CHECK(err, "bpf_obj_get_info_by_fd", "failed\n")) {
- log_err("bpf_obj_get_info_by_fd");
- return 0;
- }
- if (CHECK(info_len != sizeof(info), "bpf_obj_get_info_by_fd",
- "unexpected info len %u\n", info_len))
- return 0;
-
- return info.prog_id;
-}
-
static void query_lookup_prog(struct test_sk_lookup *skel)
{
struct bpf_link *link[3] = {};
+ struct bpf_link_info info;
__u32 attach_flags = 0;
__u32 prog_ids[3] = {};
__u32 prog_cnt = 3;
@@ -534,18 +511,36 @@ static void query_lookup_prog(struct test_sk_lookup *skel)
if (CHECK(prog_cnt != 3, "bpf_prog_query",
"wrong program count on query: %u", prog_cnt))
goto detach;
- prog_id = link_info_prog_id(link[0]);
+ prog_id = link_info_prog_id(link[0], &info);
CHECK(prog_ids[0] != prog_id, "bpf_prog_query",
"invalid program #0 id on query: %u != %u\n",
prog_ids[0], prog_id);
- prog_id = link_info_prog_id(link[1]);
+ CHECK(info.netns.netns_ino == 0, "netns_ino",
+ "unexpected netns_ino: %u\n", info.netns.netns_ino);
+ prog_id = link_info_prog_id(link[1], &info);
CHECK(prog_ids[1] != prog_id, "bpf_prog_query",
"invalid program #1 id on query: %u != %u\n",
prog_ids[1], prog_id);
- prog_id = link_info_prog_id(link[2]);
+ CHECK(info.netns.netns_ino == 0, "netns_ino",
+ "unexpected netns_ino: %u\n", info.netns.netns_ino);
+ prog_id = link_info_prog_id(link[2], &info);
CHECK(prog_ids[2] != prog_id, "bpf_prog_query",
"invalid program #2 id on query: %u != %u\n",
prog_ids[2], prog_id);
+ CHECK(info.netns.netns_ino == 0, "netns_ino",
+ "unexpected netns_ino: %u\n", info.netns.netns_ino);
+
+ err = bpf_link__detach(link[0]);
+ if (CHECK(err, "link_detach", "failed %d\n", err))
+ goto detach;
+
+ /* prog id is still there, but netns_ino is zeroed out */
+ prog_id = link_info_prog_id(link[0], &info);
+ CHECK(prog_ids[0] != prog_id, "bpf_prog_query",
+ "invalid program #0 id on query: %u != %u\n",
+ prog_ids[0], prog_id);
+ CHECK(info.netns.netns_ino != 0, "netns_ino",
+ "unexpected netns_ino: %u\n", info.netns.netns_ino);
detach:
if (link[2])
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_link.c b/tools/testing/selftests/bpf/prog_tests/xdp_link.c
index 52cba6795d40..6f814999b395 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_link.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_link.c
@@ -131,6 +131,20 @@ void test_xdp_link(void)
CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
"got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
+ err = bpf_link__detach(link);
+ if (CHECK(err, "link_detach", "failed %d\n", err))
+ goto cleanup;
+
+ memset(&link_info, 0, sizeof(link_info));
+ err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
+ if (CHECK(err, "link_info", "failed: %d\n", err))
+ goto cleanup;
+ CHECK(link_info.prog_id != id1, "link_prog_id",
+ "got %u != exp %u\n", link_info.prog_id, id1);
+ /* ifindex should be zeroed out */
+ CHECK(link_info.xdp.ifindex != 0, "link_ifindex",
+ "got %u != exp %u\n", link_info.xdp.ifindex, 0);
+
cleanup:
test_xdp_link__destroy(skel1);
test_xdp_link__destroy(skel2);
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index 0af6337a8962..800d503e5cb4 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -64,3 +64,17 @@ int parse_num_list(const char *s, bool **num_set, int *num_set_len)
return 0;
}
+
+__u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info)
+{
+ __u32 info_len = sizeof(*info);
+ int err;
+
+ memset(info, 0, sizeof(*info));
+ err = bpf_obj_get_info_by_fd(bpf_link__fd(link), info, &info_len);
+ if (err) {
+ printf("failed to get link info: %d\n", -errno);
+ return 0;
+ }
+ return info->prog_id;
+}
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 923b51762759..d4f8e749611b 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -1,5 +1,8 @@
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (C) 2020 Facebook, Inc. */
#include <stdbool.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
int parse_num_list(const char *s, bool **set, int *set_len);
+__u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info);
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-18 17:44:02 +0300