Commit 55cc3768 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov

libbpf: Add link-based API for tcx

Implement tcx BPF link support for libbpf.

The bpf_program__attach_fd() API has been refactored slightly in order to pass
bpf_link_create_opts pointer as input.

A new bpf_program__attach_tcx() has been added on top of this which allows for
passing all relevant data via extensible struct bpf_tcx_opts.

The program sections tcx/ingress and tcx/egress correspond to the hook locations
for tc ingress and egress, respectively.

For concrete usage examples, see the extensive selftests that have been
developed as part of this series.
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230719140858.13224-5-daniel@iogearbox.netSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent fe20ce3a
...@@ -719,9 +719,9 @@ int bpf_link_create(int prog_fd, int target_fd, ...@@ -719,9 +719,9 @@ int bpf_link_create(int prog_fd, int target_fd,
const struct bpf_link_create_opts *opts) const struct bpf_link_create_opts *opts)
{ {
const size_t attr_sz = offsetofend(union bpf_attr, link_create); const size_t attr_sz = offsetofend(union bpf_attr, link_create);
__u32 target_btf_id, iter_info_len; __u32 target_btf_id, iter_info_len, relative_id;
int fd, err, relative_fd;
union bpf_attr attr; union bpf_attr attr;
int fd, err;
if (!OPTS_VALID(opts, bpf_link_create_opts)) if (!OPTS_VALID(opts, bpf_link_create_opts))
return libbpf_err(-EINVAL); return libbpf_err(-EINVAL);
...@@ -783,6 +783,22 @@ int bpf_link_create(int prog_fd, int target_fd, ...@@ -783,6 +783,22 @@ int bpf_link_create(int prog_fd, int target_fd,
if (!OPTS_ZEROED(opts, netfilter)) if (!OPTS_ZEROED(opts, netfilter))
return libbpf_err(-EINVAL); return libbpf_err(-EINVAL);
break; break;
case BPF_TCX_INGRESS:
case BPF_TCX_EGRESS:
relative_fd = OPTS_GET(opts, tcx.relative_fd, 0);
relative_id = OPTS_GET(opts, tcx.relative_id, 0);
if (relative_fd && relative_id)
return libbpf_err(-EINVAL);
if (relative_id) {
attr.link_create.tcx.relative_id = relative_id;
attr.link_create.flags |= BPF_F_ID;
} else {
attr.link_create.tcx.relative_fd = relative_fd;
}
attr.link_create.tcx.expected_revision = OPTS_GET(opts, tcx.expected_revision, 0);
if (!OPTS_ZEROED(opts, tcx))
return libbpf_err(-EINVAL);
break;
default: default:
if (!OPTS_ZEROED(opts, flags)) if (!OPTS_ZEROED(opts, flags))
return libbpf_err(-EINVAL); return libbpf_err(-EINVAL);
......
...@@ -401,6 +401,11 @@ struct bpf_link_create_opts { ...@@ -401,6 +401,11 @@ struct bpf_link_create_opts {
__s32 priority; __s32 priority;
__u32 flags; __u32 flags;
} netfilter; } netfilter;
struct {
__u32 relative_fd;
__u32 relative_id;
__u64 expected_revision;
} tcx;
}; };
size_t :0; size_t :0;
}; };
......
...@@ -134,6 +134,7 @@ static const char * const link_type_name[] = { ...@@ -134,6 +134,7 @@ static const char * const link_type_name[] = {
[BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi",
[BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops",
[BPF_LINK_TYPE_NETFILTER] = "netfilter", [BPF_LINK_TYPE_NETFILTER] = "netfilter",
[BPF_LINK_TYPE_TCX] = "tcx",
}; };
static const char * const map_type_name[] = { static const char * const map_type_name[] = {
...@@ -11854,11 +11855,10 @@ static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_li ...@@ -11854,11 +11855,10 @@ static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_li
} }
static struct bpf_link * static struct bpf_link *
bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id, bpf_program_attach_fd(const struct bpf_program *prog,
const char *target_name) int target_fd, const char *target_name,
const struct bpf_link_create_opts *opts)
{ {
DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
.target_btf_id = btf_id);
enum bpf_attach_type attach_type; enum bpf_attach_type attach_type;
char errmsg[STRERR_BUFSIZE]; char errmsg[STRERR_BUFSIZE];
struct bpf_link *link; struct bpf_link *link;
...@@ -11876,7 +11876,7 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id ...@@ -11876,7 +11876,7 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id
link->detach = &bpf_link__detach_fd; link->detach = &bpf_link__detach_fd;
attach_type = bpf_program__expected_attach_type(prog); attach_type = bpf_program__expected_attach_type(prog);
link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts); link_fd = bpf_link_create(prog_fd, target_fd, attach_type, opts);
if (link_fd < 0) { if (link_fd < 0) {
link_fd = -errno; link_fd = -errno;
free(link); free(link);
...@@ -11892,19 +11892,54 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id ...@@ -11892,19 +11892,54 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id
struct bpf_link * struct bpf_link *
bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd) bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd)
{ {
return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", NULL);
} }
struct bpf_link * struct bpf_link *
bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd) bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
{ {
return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); return bpf_program_attach_fd(prog, netns_fd, "netns", NULL);
} }
struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex) struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
{ {
/* target_fd/target_ifindex use the same field in LINK_CREATE */ /* target_fd/target_ifindex use the same field in LINK_CREATE */
return bpf_program__attach_fd(prog, ifindex, 0, "xdp"); return bpf_program_attach_fd(prog, ifindex, "xdp", NULL);
}
struct bpf_link *
bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
const struct bpf_tcx_opts *opts)
{
LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
__u32 relative_id;
int relative_fd;
if (!OPTS_VALID(opts, bpf_tcx_opts))
return libbpf_err_ptr(-EINVAL);
relative_id = OPTS_GET(opts, relative_id, 0);
relative_fd = OPTS_GET(opts, relative_fd, 0);
/* validate we don't have unexpected combinations of non-zero fields */
if (!ifindex) {
pr_warn("prog '%s': target netdevice ifindex cannot be zero\n",
prog->name);
return libbpf_err_ptr(-EINVAL);
}
if (relative_fd && relative_id) {
pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",
prog->name);
return libbpf_err_ptr(-EINVAL);
}
link_create_opts.tcx.expected_revision = OPTS_GET(opts, expected_revision, 0);
link_create_opts.tcx.relative_fd = relative_fd;
link_create_opts.tcx.relative_id = relative_id;
link_create_opts.flags = OPTS_GET(opts, flags, 0);
/* target_fd/target_ifindex use the same field in LINK_CREATE */
return bpf_program_attach_fd(prog, ifindex, "tcx", &link_create_opts);
} }
struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
...@@ -11926,11 +11961,16 @@ struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, ...@@ -11926,11 +11961,16 @@ struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
} }
if (target_fd) { if (target_fd) {
LIBBPF_OPTS(bpf_link_create_opts, target_opts);
btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd);
if (btf_id < 0) if (btf_id < 0)
return libbpf_err_ptr(btf_id); return libbpf_err_ptr(btf_id);
return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace"); target_opts.target_btf_id = btf_id;
return bpf_program_attach_fd(prog, target_fd, "freplace",
&target_opts);
} else { } else {
/* no target, so use raw_tracepoint_open for compatibility /* no target, so use raw_tracepoint_open for compatibility
* with old kernels * with old kernels
......
...@@ -733,6 +733,21 @@ LIBBPF_API struct bpf_link * ...@@ -733,6 +733,21 @@ LIBBPF_API struct bpf_link *
bpf_program__attach_netfilter(const struct bpf_program *prog, bpf_program__attach_netfilter(const struct bpf_program *prog,
const struct bpf_netfilter_opts *opts); const struct bpf_netfilter_opts *opts);
struct bpf_tcx_opts {
/* size of this struct, for forward/backward compatibility */
size_t sz;
__u32 flags;
__u32 relative_fd;
__u32 relative_id;
__u64 expected_revision;
size_t :0;
};
#define bpf_tcx_opts__last_field expected_revision
LIBBPF_API struct bpf_link *
bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
const struct bpf_tcx_opts *opts);
struct bpf_map; struct bpf_map;
LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map); LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
......
...@@ -397,4 +397,5 @@ LIBBPF_1.3.0 { ...@@ -397,4 +397,5 @@ LIBBPF_1.3.0 {
bpf_obj_pin_opts; bpf_obj_pin_opts;
bpf_prog_detach_opts; bpf_prog_detach_opts;
bpf_program__attach_netfilter; bpf_program__attach_netfilter;
bpf_program__attach_tcx;
} LIBBPF_1.2.0; } LIBBPF_1.2.0;
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