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-rw-r--r--tools/bpf/bpftool/feature.c764
1 files changed, 764 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
new file mode 100644
index 000000000000..d672d9086fff
--- /dev/null
+++ b/tools/bpf/bpftool/feature.c
@@ -0,0 +1,764 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (c) 2019 Netronome Systems, Inc. */
+
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <sys/utsname.h>
+#include <sys/vfs.h>
+
+#include <linux/filter.h>
+#include <linux/limits.h>
+
+#include <bpf.h>
+#include <libbpf.h>
+
+#include "main.h"
+
+#ifndef PROC_SUPER_MAGIC
+# define PROC_SUPER_MAGIC 0x9fa0
+#endif
+
+enum probe_component {
+ COMPONENT_UNSPEC,
+ COMPONENT_KERNEL,
+ COMPONENT_DEVICE,
+};
+
+#define BPF_HELPER_MAKE_ENTRY(name) [BPF_FUNC_ ## name] = "bpf_" # name
+static const char * const helper_name[] = {
+ __BPF_FUNC_MAPPER(BPF_HELPER_MAKE_ENTRY)
+};
+
+#undef BPF_HELPER_MAKE_ENTRY
+
+/* Miscellaneous utility functions */
+
+static bool check_procfs(void)
+{
+ struct statfs st_fs;
+
+ if (statfs("/proc", &st_fs) < 0)
+ return false;
+ if ((unsigned long)st_fs.f_type != PROC_SUPER_MAGIC)
+ return false;
+
+ return true;
+}
+
+static void uppercase(char *str, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len && str[i] != '\0'; i++)
+ str[i] = toupper(str[i]);
+}
+
+/* Printing utility functions */
+
+static void
+print_bool_feature(const char *feat_name, const char *plain_name,
+ const char *define_name, bool res, const char *define_prefix)
+{
+ if (json_output)
+ jsonw_bool_field(json_wtr, feat_name, res);
+ else if (define_prefix)
+ printf("#define %s%sHAVE_%s\n", define_prefix,
+ res ? "" : "NO_", define_name);
+ else
+ printf("%s is %savailable\n", plain_name, res ? "" : "NOT ");
+}
+
+static void print_kernel_option(const char *name, const char *value)
+{
+ char *endptr;
+ int res;
+
+ /* No support for C-style ouptut */
+
+ if (json_output) {
+ if (!value) {
+ jsonw_null_field(json_wtr, name);
+ return;
+ }
+ errno = 0;
+ res = strtol(value, &endptr, 0);
+ if (!errno && *endptr == '\n')
+ jsonw_int_field(json_wtr, name, res);
+ else
+ jsonw_string_field(json_wtr, name, value);
+ } else {
+ if (value)
+ printf("%s is set to %s\n", name, value);
+ else
+ printf("%s is not set\n", name);
+ }
+}
+
+static void
+print_start_section(const char *json_title, const char *plain_title,
+ const char *define_comment, const char *define_prefix)
+{
+ if (json_output) {
+ jsonw_name(json_wtr, json_title);
+ jsonw_start_object(json_wtr);
+ } else if (define_prefix) {
+ printf("%s\n", define_comment);
+ } else {
+ printf("%s\n", plain_title);
+ }
+}
+
+static void
+print_end_then_start_section(const char *json_title, const char *plain_title,
+ const char *define_comment,
+ const char *define_prefix)
+{
+ if (json_output)
+ jsonw_end_object(json_wtr);
+ else
+ printf("\n");
+
+ print_start_section(json_title, plain_title, define_comment,
+ define_prefix);
+}
+
+/* Probing functions */
+
+static int read_procfs(const char *path)
+{
+ char *endptr, *line = NULL;
+ size_t len = 0;
+ FILE *fd;
+ int res;
+
+ fd = fopen(path, "r");
+ if (!fd)
+ return -1;
+
+ res = getline(&line, &len, fd);
+ fclose(fd);
+ if (res < 0)
+ return -1;
+
+ errno = 0;
+ res = strtol(line, &endptr, 10);
+ if (errno || *line == '\0' || *endptr != '\n')
+ res = -1;
+ free(line);
+
+ return res;
+}
+
+static void probe_unprivileged_disabled(void)
+{
+ int res;
+
+ /* No support for C-style ouptut */
+
+ res = read_procfs("/proc/sys/kernel/unprivileged_bpf_disabled");
+ if (json_output) {
+ jsonw_int_field(json_wtr, "unprivileged_bpf_disabled", res);
+ } else {
+ switch (res) {
+ case 0:
+ printf("bpf() syscall for unprivileged users is enabled\n");
+ break;
+ case 1:
+ printf("bpf() syscall restricted to privileged users\n");
+ break;
+ case -1:
+ printf("Unable to retrieve required privileges for bpf() syscall\n");
+ break;
+ default:
+ printf("bpf() syscall restriction has unknown value %d\n", res);
+ }
+ }
+}
+
+static void probe_jit_enable(void)
+{
+ int res;
+
+ /* No support for C-style ouptut */
+
+ res = read_procfs("/proc/sys/net/core/bpf_jit_enable");
+ if (json_output) {
+ jsonw_int_field(json_wtr, "bpf_jit_enable", res);
+ } else {
+ switch (res) {
+ case 0:
+ printf("JIT compiler is disabled\n");
+ break;
+ case 1:
+ printf("JIT compiler is enabled\n");
+ break;
+ case 2:
+ printf("JIT compiler is enabled with debugging traces in kernel logs\n");
+ break;
+ case -1:
+ printf("Unable to retrieve JIT-compiler status\n");
+ break;
+ default:
+ printf("JIT-compiler status has unknown value %d\n",
+ res);
+ }
+ }
+}
+
+static void probe_jit_harden(void)
+{
+ int res;
+
+ /* No support for C-style ouptut */
+
+ res = read_procfs("/proc/sys/net/core/bpf_jit_harden");
+ if (json_output) {
+ jsonw_int_field(json_wtr, "bpf_jit_harden", res);
+ } else {
+ switch (res) {
+ case 0:
+ printf("JIT compiler hardening is disabled\n");
+ break;
+ case 1:
+ printf("JIT compiler hardening is enabled for unprivileged users\n");
+ break;
+ case 2:
+ printf("JIT compiler hardening is enabled for all users\n");
+ break;
+ case -1:
+ printf("Unable to retrieve JIT hardening status\n");
+ break;
+ default:
+ printf("JIT hardening status has unknown value %d\n",
+ res);
+ }
+ }
+}
+
+static void probe_jit_kallsyms(void)
+{
+ int res;
+
+ /* No support for C-style ouptut */
+
+ res = read_procfs("/proc/sys/net/core/bpf_jit_kallsyms");
+ if (json_output) {
+ jsonw_int_field(json_wtr, "bpf_jit_kallsyms", res);
+ } else {
+ switch (res) {
+ case 0:
+ printf("JIT compiler kallsyms exports are disabled\n");
+ break;
+ case 1:
+ printf("JIT compiler kallsyms exports are enabled for root\n");
+ break;
+ case -1:
+ printf("Unable to retrieve JIT kallsyms export status\n");
+ break;
+ default:
+ printf("JIT kallsyms exports status has unknown value %d\n", res);
+ }
+ }
+}
+
+static void probe_jit_limit(void)
+{
+ int res;
+
+ /* No support for C-style ouptut */
+
+ res = read_procfs("/proc/sys/net/core/bpf_jit_limit");
+ if (json_output) {
+ jsonw_int_field(json_wtr, "bpf_jit_limit", res);
+ } else {
+ switch (res) {
+ case -1:
+ printf("Unable to retrieve global memory limit for JIT compiler for unprivileged users\n");
+ break;
+ default:
+ printf("Global memory limit for JIT compiler for unprivileged users is %d bytes\n", res);
+ }
+ }
+}
+
+static char *get_kernel_config_option(FILE *fd, const char *option)
+{
+ size_t line_n = 0, optlen = strlen(option);
+ char *res, *strval, *line = NULL;
+ ssize_t n;
+
+ rewind(fd);
+ while ((n = getline(&line, &line_n, fd)) > 0) {
+ if (strncmp(line, option, optlen))
+ continue;
+ /* Check we have at least '=', value, and '\n' */
+ if (strlen(line) < optlen + 3)
+ continue;
+ if (*(line + optlen) != '=')
+ continue;
+
+ /* Trim ending '\n' */
+ line[strlen(line) - 1] = '\0';
+
+ /* Copy and return config option value */
+ strval = line + optlen + 1;
+ res = strdup(strval);
+ free(line);
+ return res;
+ }
+ free(line);
+
+ return NULL;
+}
+
+static void probe_kernel_image_config(void)
+{
+ static const char * const options[] = {
+ /* Enable BPF */
+ "CONFIG_BPF",
+ /* Enable bpf() syscall */
+ "CONFIG_BPF_SYSCALL",
+ /* Does selected architecture support eBPF JIT compiler */
+ "CONFIG_HAVE_EBPF_JIT",
+ /* Compile eBPF JIT compiler */
+ "CONFIG_BPF_JIT",
+ /* Avoid compiling eBPF interpreter (use JIT only) */
+ "CONFIG_BPF_JIT_ALWAYS_ON",
+
+ /* cgroups */
+ "CONFIG_CGROUPS",
+ /* BPF programs attached to cgroups */
+ "CONFIG_CGROUP_BPF",
+ /* bpf_get_cgroup_classid() helper */
+ "CONFIG_CGROUP_NET_CLASSID",
+ /* bpf_skb_{,ancestor_}cgroup_id() helpers */
+ "CONFIG_SOCK_CGROUP_DATA",
+
+ /* Tracing: attach BPF to kprobes, tracepoints, etc. */
+ "CONFIG_BPF_EVENTS",
+ /* Kprobes */
+ "CONFIG_KPROBE_EVENTS",
+ /* Uprobes */
+ "CONFIG_UPROBE_EVENTS",
+ /* Tracepoints */
+ "CONFIG_TRACING",
+ /* Syscall tracepoints */
+ "CONFIG_FTRACE_SYSCALLS",
+ /* bpf_override_return() helper support for selected arch */
+ "CONFIG_FUNCTION_ERROR_INJECTION",
+ /* bpf_override_return() helper */
+ "CONFIG_BPF_KPROBE_OVERRIDE",
+
+ /* Network */
+ "CONFIG_NET",
+ /* AF_XDP sockets */
+ "CONFIG_XDP_SOCKETS",
+ /* BPF_PROG_TYPE_LWT_* and related helpers */
+ "CONFIG_LWTUNNEL_BPF",
+ /* BPF_PROG_TYPE_SCHED_ACT, TC (traffic control) actions */
+ "CONFIG_NET_ACT_BPF",
+ /* BPF_PROG_TYPE_SCHED_CLS, TC filters */
+ "CONFIG_NET_CLS_BPF",
+ /* TC clsact qdisc */
+ "CONFIG_NET_CLS_ACT",
+ /* Ingress filtering with TC */
+ "CONFIG_NET_SCH_INGRESS",
+ /* bpf_skb_get_xfrm_state() helper */
+ "CONFIG_XFRM",
+ /* bpf_get_route_realm() helper */
+ "CONFIG_IP_ROUTE_CLASSID",
+ /* BPF_PROG_TYPE_LWT_SEG6_LOCAL and related helpers */
+ "CONFIG_IPV6_SEG6_BPF",
+ /* BPF_PROG_TYPE_LIRC_MODE2 and related helpers */
+ "CONFIG_BPF_LIRC_MODE2",
+ /* BPF stream parser and BPF socket maps */
+ "CONFIG_BPF_STREAM_PARSER",
+ /* xt_bpf module for passing BPF programs to netfilter */
+ "CONFIG_NETFILTER_XT_MATCH_BPF",
+ /* bpfilter back-end for iptables */
+ "CONFIG_BPFILTER",
+ /* bpftilter module with "user mode helper" */
+ "CONFIG_BPFILTER_UMH",
+
+ /* test_bpf module for BPF tests */
+ "CONFIG_TEST_BPF",
+ };
+ char *value, *buf = NULL;
+ struct utsname utsn;
+ char path[PATH_MAX];
+ size_t i, n;
+ ssize_t ret;
+ FILE *fd;
+
+ if (uname(&utsn))
+ goto no_config;
+
+ snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
+
+ fd = fopen(path, "r");
+ if (!fd && errno == ENOENT) {
+ /* Some distributions put the config file at /proc/config, give
+ * it a try.
+ * Sometimes it is also at /proc/config.gz but we do not try
+ * this one for now, it would require linking against libz.
+ */
+ fd = fopen("/proc/config", "r");
+ }
+ if (!fd) {
+ p_info("skipping kernel config, can't open file: %s",
+ strerror(errno));
+ goto no_config;
+ }
+ /* Sanity checks */
+ ret = getline(&buf, &n, fd);
+ ret = getline(&buf, &n, fd);
+ if (!buf || !ret) {
+ p_info("skipping kernel config, can't read from file: %s",
+ strerror(errno));
+ free(buf);
+ goto no_config;
+ }
+ if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
+ p_info("skipping kernel config, can't find correct file");
+ free(buf);
+ goto no_config;
+ }
+ free(buf);
+
+ for (i = 0; i < ARRAY_SIZE(options); i++) {
+ value = get_kernel_config_option(fd, options[i]);
+ print_kernel_option(options[i], value);
+ free(value);
+ }
+ fclose(fd);
+ return;
+
+no_config:
+ for (i = 0; i < ARRAY_SIZE(options); i++)
+ print_kernel_option(options[i], NULL);
+}
+
+static bool probe_bpf_syscall(const char *define_prefix)
+{
+ bool res;
+
+ bpf_load_program(BPF_PROG_TYPE_UNSPEC, NULL, 0, NULL, 0, NULL, 0);
+ res = (errno != ENOSYS);
+
+ print_bool_feature("have_bpf_syscall",
+ "bpf() syscall",
+ "BPF_SYSCALL",
+ res, define_prefix);
+
+ return res;
+}
+
+static void
+probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types,
+ const char *define_prefix, __u32 ifindex)
+{
+ char feat_name[128], plain_desc[128], define_name[128];
+ const char *plain_comment = "eBPF program_type ";
+ size_t maxlen;
+ bool res;
+
+ if (ifindex)
+ /* Only test offload-able program types */
+ switch (prog_type) {
+ case BPF_PROG_TYPE_SCHED_CLS:
+ case BPF_PROG_TYPE_XDP:
+ break;
+ default:
+ return;
+ }
+
+ res = bpf_probe_prog_type(prog_type, ifindex);
+
+ supported_types[prog_type] |= res;
+
+ maxlen = sizeof(plain_desc) - strlen(plain_comment) - 1;
+ if (strlen(prog_type_name[prog_type]) > maxlen) {
+ p_info("program type name too long");
+ return;
+ }
+
+ sprintf(feat_name, "have_%s_prog_type", prog_type_name[prog_type]);
+ sprintf(define_name, "%s_prog_type", prog_type_name[prog_type]);
+ uppercase(define_name, sizeof(define_name));
+ sprintf(plain_desc, "%s%s", plain_comment, prog_type_name[prog_type]);
+ print_bool_feature(feat_name, plain_desc, define_name, res,
+ define_prefix);
+}
+
+static void
+probe_map_type(enum bpf_map_type map_type, const char *define_prefix,
+ __u32 ifindex)
+{
+ char feat_name[128], plain_desc[128], define_name[128];
+ const char *plain_comment = "eBPF map_type ";
+ size_t maxlen;
+ bool res;
+
+ res = bpf_probe_map_type(map_type, ifindex);
+
+ maxlen = sizeof(plain_desc) - strlen(plain_comment) - 1;
+ if (strlen(map_type_name[map_type]) > maxlen) {
+ p_info("map type name too long");
+ return;
+ }
+
+ sprintf(feat_name, "have_%s_map_type", map_type_name[map_type]);
+ sprintf(define_name, "%s_map_type", map_type_name[map_type]);
+ uppercase(define_name, sizeof(define_name));
+ sprintf(plain_desc, "%s%s", plain_comment, map_type_name[map_type]);
+ print_bool_feature(feat_name, plain_desc, define_name, res,
+ define_prefix);
+}
+
+static void
+probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type,
+ const char *define_prefix, __u32 ifindex)
+{
+ const char *ptype_name = prog_type_name[prog_type];
+ char feat_name[128];
+ unsigned int id;
+ bool res;
+
+ if (ifindex)
+ /* Only test helpers for offload-able program types */
+ switch (prog_type) {
+ case BPF_PROG_TYPE_SCHED_CLS:
+ case BPF_PROG_TYPE_XDP:
+ break;
+ default:
+ return;
+ }
+
+ if (json_output) {
+ sprintf(feat_name, "%s_available_helpers", ptype_name);
+ jsonw_name(json_wtr, feat_name);
+ jsonw_start_array(json_wtr);
+ } else if (!define_prefix) {
+ printf("eBPF helpers supported for program type %s:",
+ ptype_name);
+ }
+
+ for (id = 1; id < ARRAY_SIZE(helper_name); id++) {
+ if (!supported_type)
+ res = false;
+ else
+ res = bpf_probe_helper(id, prog_type, ifindex);
+
+ if (json_output) {
+ if (res)
+ jsonw_string(json_wtr, helper_name[id]);
+ } else if (define_prefix) {
+ printf("#define %sBPF__PROG_TYPE_%s__HELPER_%s %s\n",
+ define_prefix, ptype_name, helper_name[id],
+ res ? "1" : "0");
+ } else {
+ if (res)
+ printf("\n\t- %s", helper_name[id]);
+ }
+ }
+
+ if (json_output)
+ jsonw_end_array(json_wtr);
+ else if (!define_prefix)
+ printf("\n");
+}
+
+static int do_probe(int argc, char **argv)
+{
+ enum probe_component target = COMPONENT_UNSPEC;
+ const char *define_prefix = NULL;
+ bool supported_types[128] = {};
+ __u32 ifindex = 0;
+ unsigned int i;
+ char *ifname;
+
+ /* Detection assumes user has sufficient privileges (CAP_SYS_ADMIN).
+ * Let's approximate, and restrict usage to root user only.
+ */
+ if (geteuid()) {
+ p_err("please run this command as root user");
+ return -1;
+ }
+
+ set_max_rlimit();
+
+ while (argc) {
+ if (is_prefix(*argv, "kernel")) {
+ if (target != COMPONENT_UNSPEC) {
+ p_err("component to probe already specified");
+ return -1;
+ }
+ target = COMPONENT_KERNEL;
+ NEXT_ARG();
+ } else if (is_prefix(*argv, "dev")) {
+ NEXT_ARG();
+
+ if (target != COMPONENT_UNSPEC || ifindex) {
+ p_err("component to probe already specified");
+ return -1;
+ }
+ if (!REQ_ARGS(1))
+ return -1;
+
+ target = COMPONENT_DEVICE;
+ ifname = GET_ARG();
+ ifindex = if_nametoindex(ifname);
+ if (!ifindex) {
+ p_err("unrecognized netdevice '%s': %s", ifname,
+ strerror(errno));
+ return -1;
+ }
+ } else if (is_prefix(*argv, "macros") && !define_prefix) {
+ define_prefix = "";
+ NEXT_ARG();
+ } else if (is_prefix(*argv, "prefix")) {
+ if (!define_prefix) {
+ p_err("'prefix' argument can only be use after 'macros'");
+ return -1;
+ }
+ if (strcmp(define_prefix, "")) {
+ p_err("'prefix' already defined");
+ return -1;
+ }
+ NEXT_ARG();
+
+ if (!REQ_ARGS(1))
+ return -1;
+ define_prefix = GET_ARG();
+ } else {
+ p_err("expected no more arguments, 'kernel', 'dev', 'macros' or 'prefix', got: '%s'?",
+ *argv);
+ return -1;
+ }
+ }
+
+ if (json_output) {
+ define_prefix = NULL;
+ jsonw_start_object(json_wtr);
+ }
+
+ switch (target) {
+ case COMPONENT_KERNEL:
+ case COMPONENT_UNSPEC:
+ if (define_prefix)
+ break;
+
+ print_start_section("system_config",
+ "Scanning system configuration...",
+ NULL, /* define_comment never used here */
+ NULL); /* define_prefix always NULL here */
+ if (check_procfs()) {
+ probe_unprivileged_disabled();
+ probe_jit_enable();
+ probe_jit_harden();
+ probe_jit_kallsyms();
+ probe_jit_limit();
+ } else {
+ p_info("/* procfs not mounted, skipping related probes */");
+ }
+ probe_kernel_image_config();
+ if (json_output)
+ jsonw_end_object(json_wtr);
+ else
+ printf("\n");
+ break;
+ default:
+ break;
+ }
+
+ print_start_section("syscall_config",
+ "Scanning system call availability...",
+ "/*** System call availability ***/",
+ define_prefix);
+
+ if (!probe_bpf_syscall(define_prefix))
+ /* bpf() syscall unavailable, don't probe other BPF features */
+ goto exit_close_json;
+
+ print_end_then_start_section("program_types",
+ "Scanning eBPF program types...",
+ "/*** eBPF program types ***/",
+ define_prefix);
+
+ for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
+ probe_prog_type(i, supported_types, define_prefix, ifindex);
+
+ print_end_then_start_section("map_types",
+ "Scanning eBPF map types...",
+ "/*** eBPF map types ***/",
+ define_prefix);
+
+ for (i = BPF_MAP_TYPE_UNSPEC + 1; i < map_type_name_size; i++)
+ probe_map_type(i, define_prefix, ifindex);
+
+ print_end_then_start_section("helpers",
+ "Scanning eBPF helper functions...",
+ "/*** eBPF helper functions ***/",
+ define_prefix);
+
+ if (define_prefix)
+ printf("/*\n"
+ " * Use %sHAVE_PROG_TYPE_HELPER(prog_type_name, helper_name)\n"
+ " * to determine if <helper_name> is available for <prog_type_name>,\n"
+ " * e.g.\n"
+ " * #if %sHAVE_PROG_TYPE_HELPER(xdp, bpf_redirect)\n"
+ " * // do stuff with this helper\n"
+ " * #elif\n"
+ " * // use a workaround\n"
+ " * #endif\n"
+ " */\n"
+ "#define %sHAVE_PROG_TYPE_HELPER(prog_type, helper) \\\n"
+ " %sBPF__PROG_TYPE_ ## prog_type ## __HELPER_ ## helper\n",
+ define_prefix, define_prefix, define_prefix,
+ define_prefix);
+ for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++)
+ probe_helpers_for_progtype(i, supported_types[i],
+ define_prefix, ifindex);
+
+exit_close_json:
+ if (json_output) {
+ /* End current "section" of probes */
+ jsonw_end_object(json_wtr);
+ /* End root object */
+ jsonw_end_object(json_wtr);
+ }
+
+ return 0;
+}
+
+static int do_help(int argc, char **argv)
+{
+ if (json_output) {
+ jsonw_null(json_wtr);
+ return 0;
+ }
+
+ fprintf(stderr,
+ "Usage: %s %s probe [COMPONENT] [macros [prefix PREFIX]]\n"
+ " %s %s help\n"
+ "\n"
+ " COMPONENT := { kernel | dev NAME }\n"
+ "",
+ bin_name, argv[-2], bin_name, argv[-2]);
+
+ return 0;
+}
+
+static const struct cmd cmds[] = {
+ { "probe", do_probe },
+ { "help", do_help },
+ { 0 }
+};
+
+int do_feature(int argc, char **argv)
+{
+ return cmd_select(cmds, argc, argv, do_help);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 05:20:18 +0100