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Message-ID: <160010000935.80898.4271262373666475188.stgit@toke.dk>
Date: Mon, 14 Sep 2020 18:13:29 +0200
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Alexei Starovoitov <ast@...nel.org>
Cc: Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Andrii Nakryiko <andriin@...com>,
John Fastabend <john.fastabend@...il.com>,
Jiri Olsa <jolsa@...hat.com>,
Eelco Chaudron <echaudro@...hat.com>,
KP Singh <kpsingh@...omium.org>, netdev@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH bpf-next v4 6/8] libbpf: add support for freplace attachment
in bpf_link_create
From: Toke Høiland-Jørgensen <toke@...hat.com>
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@...hat.com>
---
tools/lib/bpf/bpf.c | 1 +
tools/lib/bpf/bpf.h | 3 ++-
tools/lib/bpf/libbpf.c | 24 ++++++++++++++++++------
tools/lib/bpf/libbpf.h | 3 +++
tools/lib/bpf/libbpf.map | 1 +
5 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 82b983ff6569..e928456c0dd6 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -599,6 +599,7 @@ int bpf_link_create(int prog_fd, int target_fd,
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);
+ attr.link_create.target_btf_id = OPTS_GET(opts, target_btf_id, 0);
return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 015d13f25fcc..f8dbf666b62b 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 550950eb1860..165131c73f40 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9322,12 +9322,14 @@ 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,
- const char *target_name)
+ int target_btf_id, const char *target_name)
{
enum bpf_attach_type attach_type;
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, link_fd;
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
+ .target_btf_id = target_btf_id);
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
@@ -9340,8 +9342,12 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd,
return ERR_PTR(-ENOMEM);
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);
+ if (bpf_program__get_type(prog) == BPF_PROG_TYPE_EXT)
+ attach_type = BPF_TRACE_FREPLACE;
+ else
+ attach_type = bpf_program__get_expected_attach_type(prog);
+
+ link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts);
if (link_fd < 0) {
link_fd = -errno;
free(link);
@@ -9357,19 +9363,25 @@ 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, int target_btf_id)
+{
+ return bpf_program__attach_fd(prog, target_fd, target_btf_id, "freplace");
}
struct bpf_link *
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index a750f67a23f6..ce5add9b9203 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, int target_btf_id);
struct bpf_map;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 92ceb48a5ca2..3cc2c42f435d 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -302,6 +302,7 @@ LIBBPF_0.1.0 {
LIBBPF_0.2.0 {
global:
+ bpf_program__attach_freplace;
bpf_program__section_name;
perf_buffer__buffer_cnt;
perf_buffer__buffer_fd;
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