@@ -33,6 +33,7 @@
#include <linux/filter.h>
#include <linux/list.h>
#include <linux/limits.h>
+#include <linux/rtnetlink.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <linux/version.h>
@@ -6847,7 +6848,7 @@ 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;
@@ -9443,6 +9444,10 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_link {
int (*detach)(struct bpf_link *link);
int (*destroy)(struct bpf_link *link);
+ union {
+ struct bpf_tc_cls_attach_id *tc_cls_id;
+ __u32 tc_act_index;
+ };
char *pin_path; /* NULL, if not pinned */
int fd; /* hook FD, -1 if not applicable */
bool disconnected;
@@ -10199,6 +10204,109 @@ struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
return link;
}
+static int bpf_link__detach_tc_cls(struct bpf_link *link)
+{
+ return bpf_tc_cls_detach_dev(link->tc_cls_id);
+}
+
+static int bpf_link__destroy_tc_cls(struct bpf_link *link)
+{
+ zfree(&link->tc_cls_id);
+ return 0;
+}
+
+struct bpf_link *bpf_program__attach_tc_cls_dev(struct bpf_program *prog,
+ __u32 ifindex, __u32 parent_id,
+ __u32 protocol,
+ const struct bpf_tc_cls_opts *opts)
+{
+ struct bpf_tc_cls_attach_id *id = NULL;
+ struct bpf_link *link = NULL;
+ char errmsg[STRERR_BUFSIZE];
+ int prog_fd, err;
+
+ 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_tc_cls;
+ link->destroy = &bpf_link__destroy_tc_cls;
+ link->fd = -1;
+
+ id = calloc(1, sizeof(*id));
+ if (!id) {
+ err = -ENOMEM;
+ goto end;
+ }
+
+ err = bpf_tc_cls_attach_dev(prog_fd, ifindex, parent_id, protocol, opts, id);
+ if (err < 0) {
+ pr_warn("prog '%s': failed to attach classifier: %s\n",
+ prog->name,
+ libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+ goto end;
+ }
+
+ link->tc_cls_id = id;
+ return link;
+
+end:
+ free(id);
+ free(link);
+ return ERR_PTR(err);
+}
+
+struct bpf_link *bpf_program__attach_tc_cls_block(struct bpf_program *prog,
+ __u32 block_index, __u32 protocol,
+ const struct bpf_tc_cls_opts *opts)
+{
+ return bpf_program__attach_tc_cls_dev(prog, TCM_IFINDEX_MAGIC_BLOCK, block_index,
+ protocol, opts);
+}
+
+static int bpf_link__detach_tc_act(struct bpf_link *link)
+{
+ return bpf_tc_act_detach(link->tc_act_index);
+}
+
+struct bpf_link *bpf_program__attach_tc_act(struct bpf_program *prog,
+ const struct bpf_tc_act_opts *opts)
+{
+ struct bpf_link *link = NULL;
+ char errmsg[STRERR_BUFSIZE];
+ int prog_fd, err;
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't attach before loading\n", prog->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ link = calloc(1, sizeof(*link));
+ if (!link)
+ return ERR_PTR(-ENOMEM);
+ link->detach = &bpf_link__detach_tc_act;
+ link->fd = -1;
+
+ err = bpf_tc_act_attach(prog_fd, opts, &link->tc_act_index);
+ if (err < 0) {
+ pr_warn("prog '%s': failed to attach action: %s\n", prog->name,
+ libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+ goto end;
+ }
+
+ return link;
+
+end:
+ free(link);
+ return ERR_PTR(err);
+}
+
enum bpf_perf_event_ret
bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
void **copy_mem, size_t *copy_size,
@@ -268,6 +268,21 @@ LIBBPF_API struct bpf_link *
bpf_program__attach_freplace(struct bpf_program *prog,
int target_fd, const char *attach_func_name);
+struct bpf_tc_cls_opts;
+struct bpf_tc_act_opts;
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tc_cls_dev(struct bpf_program *prog, __u32 ifindex,
+ __u32 parent_id, __u32 protocol,
+ const struct bpf_tc_cls_opts *opts);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tc_cls_block(struct bpf_program *prog, __u32 block_index,
+ __u32 protocol,
+ const struct bpf_tc_cls_opts *opts);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tc_act(struct bpf_program *prog,
+ const struct bpf_tc_act_opts *opts);
+
struct bpf_map;
LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map);
@@ -373,4 +373,7 @@ LIBBPF_0.4.0 {
bpf_tc_cls_replace_dev;
bpf_tc_cls_get_info_dev;
bpf_tc_cls_get_info_block;
+ bpf_program__attach_tc_cls_dev;
+ bpf_program__attach_tc_cls_block;
+ bpf_program__attach_tc_act;
} LIBBPF_0.3.0;
A high level API is provided using the aforementioned routines internally, and these return a bpf_link object to the user. These are limited to just attach for now, and can be extended to change/replace if the use case arises in the future. It is also possible to call bpf_link__disconnect on the link and switch to managing the filter/action manually if the need arises. In most cases, the higher level API should suffice. Example: struct bpf_tc_cls_info info = {}; struct bpf_object *obj; struct bpf_program *p; struct bpf_link *link; __u32 index; int fd, r; obj = bpf_object_open("foo.o"); if (IS_ERR_OR_NULL(obj)) return PTR_ERR(obj); p = bpf_object__find_program_by_title(obj, "classifier"); if (IS_ERR_OR_NULL(p)) return PTR_ERR(p); DECLARE_LIBBPF_OPTS(bpf_tc_cls_opts, opts, .handle = 1); link = bpf_program__attach_tc_cls_dev(p, if_nametoindex("lo"), BPF_TC_CLSACT_INGRESS, ETH_P_IP, &opts); if (IS_ERR_OR_NULL(link)) return PTR_ERR(link); /* We want to take ownership of the filter, so we disconnect the * link and detach it on our own */ bpf_link__disconnect(link); r = bpf_tc_cls_get_info_dev(bpf_program__fd(fd), if_nametoindex("lo"), BPF_TC_CLSACT_INGRESS, ETH_P_IP, &opts, &info); if (r < 0) return r; /* We get the attach_id in the info struct, pass it to detach */ bpf_tc_cls_detach_dev(&info.id); bpf_link__destroy(link); Example: struct bpf_object *obj; struct bpf_program *p; struct bpf_link *link; __u32 index; int fd, r; obj = bpf_object_open("foo.o"); if (IS_ERR_OR_NULL(obj)) return PTR_ERR(obj); p = bpf_object__find_program_by_title(obj, "action"); if (IS_ERR_OR_NULL(p)) return PTR_ERR(p); /* A simple example that attaches a SCHED_ACT prog */ link = bpf_program__attach_tc_act(p, NULL); if (IS_ERR_OR_NULL(link)) return PTR_ERR(link); bpf_link__destroy(link); Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> --- tools/lib/bpf/libbpf.c | 110 ++++++++++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf.h | 15 ++++++ tools/lib/bpf/libbpf.map | 3 ++ 3 files changed, 127 insertions(+), 1 deletion(-)