On 6/3/21 11:31 PM, Kumar Kartikeya Dwivedi wrote:
This adds userspace TC-BPF management API based on bpf_link.
Reviewed-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
tools/lib/bpf/bpf.c | 8 +++++-
tools/lib/bpf/bpf.h | 8 +++++-
tools/lib/bpf/libbpf.c | 59 ++++++++++++++++++++++++++++++++++++++--
tools/lib/bpf/libbpf.h | 17 ++++++++++++
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/netlink.c | 5 ++--
tools/lib/bpf/netlink.h | 8 ++++++
7 files changed, 100 insertions(+), 6 deletions(-)
create mode 100644 tools/lib/bpf/netlink.h
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 86dcac44f32f..bebccea9bfd7 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -28,6 +28,7 @@
#include <asm/unistd.h>
#include <errno.h>
#include <linux/bpf.h>
+#include <arpa/inet.h>
#include "bpf.h"
#include "libbpf.h"
#include "libbpf_internal.h"
@@ -693,7 +694,12 @@ int bpf_link_create(int prog_fd, int target_fd,
attr.link_create.attach_type = attach_type;
attr.link_create.flags = OPTS_GET(opts, flags, 0);
- if (iter_info_len) {
+ if (attach_type == BPF_TC) {
+ attr.link_create.tc.parent = OPTS_GET(opts, tc.parent, 0);
+ attr.link_create.tc.handle = OPTS_GET(opts, tc.handle, 0);
+ attr.link_create.tc.priority = OPTS_GET(opts, tc.priority, 0);
+ attr.link_create.tc.gen_flags = OPTS_GET(opts, tc.gen_flags, 0);
+ } else 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;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 4f758f8f50cd..f2178309e9ea 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -177,8 +177,14 @@ struct bpf_link_create_opts {
union bpf_iter_link_info *iter_info;
__u32 iter_info_len;
__u32 target_btf_id;
+ struct {
+ __u32 parent;
+ __u32 handle;
+ __u32 priority;
+ __u32 gen_flags;
+ } tc;
};
-#define bpf_link_create_opts__last_field target_btf_id
+#define bpf_link_create_opts__last_field tc.gen_flags
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 1c4e20e75237..7809536980b1 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -55,6 +55,7 @@
#include "libbpf_internal.h"
#include "hashmap.h"
#include "bpf_gen_internal.h"
+#include "netlink.h"
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
@@ -7185,7 +7186,7 @@ static int bpf_object__collect_relos(struct bpf_object *obj)
for (i = 0; i < obj->nr_programs; i++) {
struct bpf_program *p = &obj->programs[i];
-
+
if (!p->nr_reloc)
continue;
@@ -10005,7 +10006,7 @@ struct bpf_link {
int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog)
{
int ret;
-
+
ret = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL);
return libbpf_err_errno(ret);
}
@@ -10613,6 +10614,60 @@ struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
}
+struct bpf_link *bpf_program__attach_tc(struct bpf_program *prog,
+ const struct bpf_tc_hook *hook,
+ const struct bpf_tc_link_opts *opts)
+{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, lopts, 0);
+ char errmsg[STRERR_BUFSIZE];
+ int prog_fd, link_fd, ret;
+ struct bpf_link *link;
+ __u32 parent;
+
+ if (!hook || !OPTS_VALID(hook, bpf_tc_hook) ||
+ !OPTS_VALID(opts, bpf_tc_link_opts))
+ return ERR_PTR(-EINVAL);
For libbpf API functions, the libbpf proposed 1.0 change
https://lore.kernel.org/bpf/20210525035935.1461796-5-andrii@xxxxxxxxxx
will return NULL and set errno properly.
So the above code probably should be
return errno = EINVAL, NULL;
+
+ if (OPTS_GET(hook, ifindex, 0) <= 0 ||
+ OPTS_GET(opts, priority, 0) > UINT16_MAX)
+ return ERR_PTR(-EINVAL);
+
+ parent = OPTS_GET(hook, parent, 0);
+
+ ret = tc_get_tcm_parent(OPTS_GET(hook, attach_point, 0),
+ &parent);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ lopts.tc.parent = parent;
+ lopts.tc.handle = OPTS_GET(opts, handle, 0);
+ lopts.tc.priority = OPTS_GET(opts, priority, 0);
+ lopts.tc.gen_flags = OPTS_GET(opts, gen_flags, 0);
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ link = calloc(1, sizeof(*link));
+ if (!link)
+ return ERR_PTR(-ENOMEM);
+ link->detach = &bpf_link__detach_fd;
+
+ link_fd = bpf_link_create(prog_fd, OPTS_GET(hook, ifindex, 0), BPF_TC, &lopts);
+ if (link_fd < 0) {
+ link_fd = -errno;
+ free(link);
+ pr_warn("prog '%s': failed to attach tc filter: %s\n",
+ prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
+ return ERR_PTR(link_fd);
+ }
+ link->fd = link_fd;
+
+ return link;
+}
+
[...]
