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-rw-r--r--tools/bpf/bpftool/link.c423
1 files changed, 423 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
new file mode 100644
index 000000000..e77e1525d
--- /dev/null
+++ b/tools/bpf/bpftool/link.c
@@ -0,0 +1,423 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2020 Facebook */
+
+#include <errno.h>
+#include <net/if.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <bpf/bpf.h>
+
+#include "json_writer.h"
+#include "main.h"
+
+static const char * const link_type_name[] = {
+ [BPF_LINK_TYPE_UNSPEC] = "unspec",
+ [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
+ [BPF_LINK_TYPE_TRACING] = "tracing",
+ [BPF_LINK_TYPE_CGROUP] = "cgroup",
+ [BPF_LINK_TYPE_ITER] = "iter",
+ [BPF_LINK_TYPE_NETNS] = "netns",
+};
+
+static int link_parse_fd(int *argc, char ***argv)
+{
+ int fd;
+
+ if (is_prefix(**argv, "id")) {
+ unsigned int id;
+ char *endptr;
+
+ NEXT_ARGP();
+
+ id = strtoul(**argv, &endptr, 0);
+ if (*endptr) {
+ p_err("can't parse %s as ID", **argv);
+ return -1;
+ }
+ NEXT_ARGP();
+
+ fd = bpf_link_get_fd_by_id(id);
+ if (fd < 0)
+ p_err("failed to get link with ID %d: %s", id, strerror(errno));
+ return fd;
+ } else if (is_prefix(**argv, "pinned")) {
+ char *path;
+
+ NEXT_ARGP();
+
+ path = **argv;
+ NEXT_ARGP();
+
+ return open_obj_pinned_any(path, BPF_OBJ_LINK);
+ }
+
+ p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
+ return -1;
+}
+
+static void
+show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr)
+{
+ jsonw_uint_field(wtr, "id", info->id);
+ if (info->type < ARRAY_SIZE(link_type_name))
+ jsonw_string_field(wtr, "type", link_type_name[info->type]);
+ else
+ jsonw_uint_field(wtr, "type", info->type);
+
+ jsonw_uint_field(json_wtr, "prog_id", info->prog_id);
+}
+
+static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
+{
+ if (attach_type < ARRAY_SIZE(attach_type_name))
+ jsonw_string_field(wtr, "attach_type",
+ attach_type_name[attach_type]);
+ else
+ jsonw_uint_field(wtr, "attach_type", attach_type);
+}
+
+static bool is_iter_map_target(const char *target_name)
+{
+ return strcmp(target_name, "bpf_map_elem") == 0 ||
+ strcmp(target_name, "bpf_sk_storage_map") == 0;
+}
+
+static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
+{
+ const char *target_name = u64_to_ptr(info->iter.target_name);
+
+ jsonw_string_field(wtr, "target_name", target_name);
+
+ if (is_iter_map_target(target_name))
+ jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
+}
+
+static int get_prog_info(int prog_id, struct bpf_prog_info *info)
+{
+ __u32 len = sizeof(*info);
+ int err, prog_fd;
+
+ prog_fd = bpf_prog_get_fd_by_id(prog_id);
+ if (prog_fd < 0)
+ return prog_fd;
+
+ memset(info, 0, sizeof(*info));
+ err = bpf_obj_get_info_by_fd(prog_fd, info, &len);
+ if (err)
+ p_err("can't get prog info: %s", strerror(errno));
+ close(prog_fd);
+ return err;
+}
+
+static int show_link_close_json(int fd, struct bpf_link_info *info)
+{
+ struct bpf_prog_info prog_info;
+ int err;
+
+ jsonw_start_object(json_wtr);
+
+ show_link_header_json(info, json_wtr);
+
+ switch (info->type) {
+ case BPF_LINK_TYPE_RAW_TRACEPOINT:
+ jsonw_string_field(json_wtr, "tp_name",
+ u64_to_ptr(info->raw_tracepoint.tp_name));
+ break;
+ case BPF_LINK_TYPE_TRACING:
+ err = get_prog_info(info->prog_id, &prog_info);
+ if (err)
+ return err;
+
+ if (prog_info.type < prog_type_name_size)
+ jsonw_string_field(json_wtr, "prog_type",
+ prog_type_name[prog_info.type]);
+ else
+ jsonw_uint_field(json_wtr, "prog_type",
+ prog_info.type);
+
+ show_link_attach_type_json(info->tracing.attach_type,
+ json_wtr);
+ break;
+ case BPF_LINK_TYPE_CGROUP:
+ jsonw_lluint_field(json_wtr, "cgroup_id",
+ info->cgroup.cgroup_id);
+ show_link_attach_type_json(info->cgroup.attach_type, json_wtr);
+ break;
+ case BPF_LINK_TYPE_ITER:
+ show_iter_json(info, json_wtr);
+ break;
+ case BPF_LINK_TYPE_NETNS:
+ jsonw_uint_field(json_wtr, "netns_ino",
+ info->netns.netns_ino);
+ show_link_attach_type_json(info->netns.attach_type, json_wtr);
+ break;
+ default:
+ break;
+ }
+
+ if (!hash_empty(link_table.table)) {
+ struct pinned_obj *obj;
+
+ jsonw_name(json_wtr, "pinned");
+ jsonw_start_array(json_wtr);
+ hash_for_each_possible(link_table.table, obj, hash, info->id) {
+ if (obj->id == info->id)
+ jsonw_string(json_wtr, obj->path);
+ }
+ jsonw_end_array(json_wtr);
+ }
+
+ emit_obj_refs_json(&refs_table, info->id, json_wtr);
+
+ jsonw_end_object(json_wtr);
+
+ return 0;
+}
+
+static void show_link_header_plain(struct bpf_link_info *info)
+{
+ printf("%u: ", info->id);
+ if (info->type < ARRAY_SIZE(link_type_name))
+ printf("%s ", link_type_name[info->type]);
+ else
+ printf("type %u ", info->type);
+
+ printf("prog %u ", info->prog_id);
+}
+
+static void show_link_attach_type_plain(__u32 attach_type)
+{
+ if (attach_type < ARRAY_SIZE(attach_type_name))
+ printf("attach_type %s ", attach_type_name[attach_type]);
+ else
+ printf("attach_type %u ", attach_type);
+}
+
+static void show_iter_plain(struct bpf_link_info *info)
+{
+ const char *target_name = u64_to_ptr(info->iter.target_name);
+
+ printf("target_name %s ", target_name);
+
+ if (is_iter_map_target(target_name))
+ printf("map_id %u ", info->iter.map.map_id);
+}
+
+static int show_link_close_plain(int fd, struct bpf_link_info *info)
+{
+ struct bpf_prog_info prog_info;
+ int err;
+
+ show_link_header_plain(info);
+
+ switch (info->type) {
+ case BPF_LINK_TYPE_RAW_TRACEPOINT:
+ printf("\n\ttp '%s' ",
+ (const char *)u64_to_ptr(info->raw_tracepoint.tp_name));
+ break;
+ case BPF_LINK_TYPE_TRACING:
+ err = get_prog_info(info->prog_id, &prog_info);
+ if (err)
+ return err;
+
+ if (prog_info.type < prog_type_name_size)
+ printf("\n\tprog_type %s ",
+ prog_type_name[prog_info.type]);
+ else
+ printf("\n\tprog_type %u ", prog_info.type);
+
+ show_link_attach_type_plain(info->tracing.attach_type);
+ break;
+ case BPF_LINK_TYPE_CGROUP:
+ printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
+ show_link_attach_type_plain(info->cgroup.attach_type);
+ break;
+ case BPF_LINK_TYPE_ITER:
+ show_iter_plain(info);
+ break;
+ case BPF_LINK_TYPE_NETNS:
+ printf("\n\tnetns_ino %u ", info->netns.netns_ino);
+ show_link_attach_type_plain(info->netns.attach_type);
+ break;
+ default:
+ break;
+ }
+
+ if (!hash_empty(link_table.table)) {
+ struct pinned_obj *obj;
+
+ hash_for_each_possible(link_table.table, obj, hash, info->id) {
+ if (obj->id == info->id)
+ printf("\n\tpinned %s", obj->path);
+ }
+ }
+ emit_obj_refs_plain(&refs_table, info->id, "\n\tpids ");
+
+ printf("\n");
+
+ return 0;
+}
+
+static int do_show_link(int fd)
+{
+ struct bpf_link_info info;
+ __u32 len = sizeof(info);
+ char buf[256];
+ int err;
+
+ memset(&info, 0, sizeof(info));
+again:
+ err = bpf_obj_get_info_by_fd(fd, &info, &len);
+ if (err) {
+ p_err("can't get link info: %s",
+ strerror(errno));
+ close(fd);
+ return err;
+ }
+ if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&
+ !info.raw_tracepoint.tp_name) {
+ info.raw_tracepoint.tp_name = (unsigned long)&buf;
+ info.raw_tracepoint.tp_name_len = sizeof(buf);
+ goto again;
+ }
+ if (info.type == BPF_LINK_TYPE_ITER &&
+ !info.iter.target_name) {
+ info.iter.target_name = (unsigned long)&buf;
+ info.iter.target_name_len = sizeof(buf);
+ goto again;
+ }
+
+ if (json_output)
+ show_link_close_json(fd, &info);
+ else
+ show_link_close_plain(fd, &info);
+
+ close(fd);
+ return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+ __u32 id = 0;
+ int err, fd;
+
+ if (show_pinned)
+ build_pinned_obj_table(&link_table, BPF_OBJ_LINK);
+ build_obj_refs_table(&refs_table, BPF_OBJ_LINK);
+
+ if (argc == 2) {
+ fd = link_parse_fd(&argc, &argv);
+ if (fd < 0)
+ return fd;
+ return do_show_link(fd);
+ }
+
+ if (argc)
+ return BAD_ARG();
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+ while (true) {
+ err = bpf_link_get_next_id(id, &id);
+ if (err) {
+ if (errno == ENOENT)
+ break;
+ p_err("can't get next link: %s%s", strerror(errno),
+ errno == EINVAL ? " -- kernel too old?" : "");
+ break;
+ }
+
+ fd = bpf_link_get_fd_by_id(id);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ continue;
+ p_err("can't get link by id (%u): %s",
+ id, strerror(errno));
+ break;
+ }
+
+ err = do_show_link(fd);
+ if (err)
+ break;
+ }
+ if (json_output)
+ jsonw_end_array(json_wtr);
+
+ delete_obj_refs_table(&refs_table);
+
+ return errno == ENOENT ? 0 : -1;
+}
+
+static int do_pin(int argc, char **argv)
+{
+ int err;
+
+ err = do_pin_any(argc, argv, link_parse_fd);
+ if (!err && json_output)
+ jsonw_null(json_wtr);
+ return err;
+}
+
+static int do_detach(int argc, char **argv)
+{
+ int err, fd;
+
+ if (argc != 2) {
+ p_err("link specifier is invalid or missing\n");
+ return 1;
+ }
+
+ fd = link_parse_fd(&argc, &argv);
+ if (fd < 0)
+ return 1;
+
+ err = bpf_link_detach(fd);
+ if (err)
+ err = -errno;
+ close(fd);
+ if (err) {
+ p_err("failed link detach: %s", strerror(-err));
+ return 1;
+ }
+
+ if (json_output)
+ jsonw_null(json_wtr);
+
+ return 0;
+}
+
+static int do_help(int argc, char **argv)
+{
+ if (json_output) {
+ jsonw_null(json_wtr);
+ return 0;
+ }
+
+ fprintf(stderr,
+ "Usage: %1$s %2$s { show | list } [LINK]\n"
+ " %1$s %2$s pin LINK FILE\n"
+ " %1$s %2$s detach LINK\n"
+ " %1$s %2$s help\n"
+ "\n"
+ " " HELP_SPEC_LINK "\n"
+ " " HELP_SPEC_OPTIONS "\n"
+ "",
+ bin_name, argv[-2]);
+
+ return 0;
+}
+
+static const struct cmd cmds[] = {
+ { "show", do_show },
+ { "list", do_show },
+ { "help", do_help },
+ { "pin", do_pin },
+ { "detach", do_detach },
+ { 0 }
+};
+
+int do_link(int argc, char **argv)
+{
+ return cmd_select(cmds, argc, argv, do_help);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 08:24:00 +0000