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authorToke Høiland-Jørgensen <toke@redhat.com>2020-09-29 14:45:53 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-09-29 13:09:24 -0700
commita535909142bf2a6f3a95cabbb8b38ce3860c4807 (patch)
treea4be0d6f869c8200ad78c5bdd33e22122842b7de /tools
parent43bc2874e779c17932c447bb06ef4d5188578bdd (diff)
libbpf: Add support for freplace attachment in bpf_link_create
This adds support for supplying a target btf ID for the bpf_link_create() operation, and adds a new bpf_program__attach_freplace() high-level API for attaching freplace functions with a target. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/160138355387.48470.18026176785351166890.stgit@toke.dk
Diffstat (limited to 'tools')
-rw-r--r--tools/lib/bpf/bpf.c18
-rw-r--r--tools/lib/bpf/bpf.h3
-rw-r--r--tools/lib/bpf/libbpf.c44
-rw-r--r--tools/lib/bpf/libbpf.h3
-rw-r--r--tools/lib/bpf/libbpf.map1
5 files changed, 60 insertions, 9 deletions
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 70575a37aa14..d27e34133973 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -586,19 +586,31 @@ int bpf_link_create(int prog_fd, int target_fd,
enum bpf_attach_type attach_type,
const struct bpf_link_create_opts *opts)
{
+ __u32 target_btf_id, iter_info_len;
union bpf_attr attr;
if (!OPTS_VALID(opts, bpf_link_create_opts))
return -EINVAL;
+ iter_info_len = OPTS_GET(opts, iter_info_len, 0);
+ target_btf_id = OPTS_GET(opts, target_btf_id, 0);
+
+ if (iter_info_len && target_btf_id)
+ return -EINVAL;
+
memset(&attr, 0, sizeof(attr));
attr.link_create.prog_fd = prog_fd;
attr.link_create.target_fd = target_fd;
attr.link_create.attach_type = attach_type;
attr.link_create.flags = OPTS_GET(opts, flags, 0);
- attr.link_create.iter_info =
- ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0));
- attr.link_create.iter_info_len = OPTS_GET(opts, iter_info_len, 0);
+
+ if (iter_info_len) {
+ attr.link_create.iter_info =
+ ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0));
+ attr.link_create.iter_info_len = iter_info_len;
+ } else if (target_btf_id) {
+ attr.link_create.target_btf_id = target_btf_id;
+ }
return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 16806810a53c..875dde20d56e 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -174,8 +174,9 @@ struct bpf_link_create_opts {
__u32 flags;
union bpf_iter_link_info *iter_info;
__u32 iter_info_len;
+ __u32 target_btf_id;
};
-#define bpf_link_create_opts__last_field iter_info_len
+#define bpf_link_create_opts__last_field target_btf_id
LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
enum bpf_attach_type attach_type,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 32dc444224d8..a4f55f8a460d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9390,9 +9390,11 @@ static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
}
static struct bpf_link *
-bpf_program__attach_fd(struct bpf_program *prog, int target_fd,
+bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id,
const char *target_name)
{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
+ .target_btf_id = btf_id);
enum bpf_attach_type attach_type;
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
@@ -9410,7 +9412,7 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd,
link->detach = &bpf_link__detach_fd;
attach_type = bpf_program__get_expected_attach_type(prog);
- link_fd = bpf_link_create(prog_fd, target_fd, attach_type, NULL);
+ link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts);
if (link_fd < 0) {
link_fd = -errno;
free(link);
@@ -9426,19 +9428,51 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd,
struct bpf_link *
bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)
{
- return bpf_program__attach_fd(prog, cgroup_fd, "cgroup");
+ return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
}
struct bpf_link *
bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)
{
- return bpf_program__attach_fd(prog, netns_fd, "netns");
+ return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
}
struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
{
/* target_fd/target_ifindex use the same field in LINK_CREATE */
- return bpf_program__attach_fd(prog, ifindex, "xdp");
+ return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
+}
+
+struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog,
+ int target_fd,
+ const char *attach_func_name)
+{
+ int btf_id;
+
+ if (!!target_fd != !!attach_func_name) {
+ pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n",
+ prog->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (prog->type != BPF_PROG_TYPE_EXT) {
+ pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace",
+ prog->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (target_fd) {
+ btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd);
+ if (btf_id < 0)
+ return ERR_PTR(btf_id);
+
+ return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace");
+ } else {
+ /* no target, so use raw_tracepoint_open for compatibility
+ * with old kernels
+ */
+ return bpf_program__attach_trace(prog);
+ }
}
struct bpf_link *
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index a750f67a23f6..6909ee81113a 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -261,6 +261,9 @@ LIBBPF_API struct bpf_link *
bpf_program__attach_netns(struct bpf_program *prog, int netns_fd);
LIBBPF_API struct bpf_link *
bpf_program__attach_xdp(struct bpf_program *prog, int ifindex);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_freplace(struct bpf_program *prog,
+ int target_fd, const char *attach_func_name);
struct bpf_map;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index f7a8ff37ef04..4ebfadf45b47 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -304,6 +304,7 @@ LIBBPF_0.2.0 {
global:
bpf_prog_bind_map;
bpf_prog_test_run_opts;
+ bpf_program__attach_freplace;
bpf_program__section_name;
btf__add_array;
btf__add_const;