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-rw-r--r--kernel/bpf/link_iter.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/kernel/bpf/link_iter.c b/kernel/bpf/link_iter.c
new file mode 100644
index 000000000..fec8005a1
--- /dev/null
+++ b/kernel/bpf/link_iter.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Red Hat, Inc. */
+#include <linux/bpf.h>
+#include <linux/fs.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+
+struct bpf_iter_seq_link_info {
+ u32 link_id;
+};
+
+static void *bpf_link_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct bpf_iter_seq_link_info *info = seq->private;
+ struct bpf_link *link;
+
+ link = bpf_link_get_curr_or_next(&info->link_id);
+ if (!link)
+ return NULL;
+
+ if (*pos == 0)
+ ++*pos;
+ return link;
+}
+
+static void *bpf_link_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct bpf_iter_seq_link_info *info = seq->private;
+
+ ++*pos;
+ ++info->link_id;
+ bpf_link_put((struct bpf_link *)v);
+ return bpf_link_get_curr_or_next(&info->link_id);
+}
+
+struct bpf_iter__bpf_link {
+ __bpf_md_ptr(struct bpf_iter_meta *, meta);
+ __bpf_md_ptr(struct bpf_link *, link);
+};
+
+DEFINE_BPF_ITER_FUNC(bpf_link, struct bpf_iter_meta *meta, struct bpf_link *link)
+
+static int __bpf_link_seq_show(struct seq_file *seq, void *v, bool in_stop)
+{
+ struct bpf_iter__bpf_link ctx;
+ struct bpf_iter_meta meta;
+ struct bpf_prog *prog;
+ int ret = 0;
+
+ ctx.meta = &meta;
+ ctx.link = v;
+ meta.seq = seq;
+ prog = bpf_iter_get_info(&meta, in_stop);
+ if (prog)
+ ret = bpf_iter_run_prog(prog, &ctx);
+
+ return ret;
+}
+
+static int bpf_link_seq_show(struct seq_file *seq, void *v)
+{
+ return __bpf_link_seq_show(seq, v, false);
+}
+
+static void bpf_link_seq_stop(struct seq_file *seq, void *v)
+{
+ if (!v)
+ (void)__bpf_link_seq_show(seq, v, true);
+ else
+ bpf_link_put((struct bpf_link *)v);
+}
+
+static const struct seq_operations bpf_link_seq_ops = {
+ .start = bpf_link_seq_start,
+ .next = bpf_link_seq_next,
+ .stop = bpf_link_seq_stop,
+ .show = bpf_link_seq_show,
+};
+
+BTF_ID_LIST(btf_bpf_link_id)
+BTF_ID(struct, bpf_link)
+
+static const struct bpf_iter_seq_info bpf_link_seq_info = {
+ .seq_ops = &bpf_link_seq_ops,
+ .init_seq_private = NULL,
+ .fini_seq_private = NULL,
+ .seq_priv_size = sizeof(struct bpf_iter_seq_link_info),
+};
+
+static struct bpf_iter_reg bpf_link_reg_info = {
+ .target = "bpf_link",
+ .ctx_arg_info_size = 1,
+ .ctx_arg_info = {
+ { offsetof(struct bpf_iter__bpf_link, link),
+ PTR_TO_BTF_ID_OR_NULL },
+ },
+ .seq_info = &bpf_link_seq_info,
+};
+
+static int __init bpf_link_iter_init(void)
+{
+ bpf_link_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_link_id;
+ return bpf_iter_reg_target(&bpf_link_reg_info);
+}
+
+late_initcall(bpf_link_iter_init);