tools: bpf: add bpftool

Add a simple tool for querying and updating BPF objects on the system.

Signed-off-by: Jakub Kicinski <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

tools/bpf/Makefile

@@ -3,6 +3,7 @@ prefix = /usr
 CC = gcc
 LEX = flex
 YACC = bison
+MAKE = make
 
 CFLAGS += -Wall -O2
 CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
@@ -13,7 +14,7 @@ CFLAGS += -D__EXPORTED_HEADERS__ -I../../include/uapi -I../../include
 %.lex.c: %.l
  $(LEX) -o $@ $<
 
-all : bpf_jit_disasm bpf_dbg bpf_asm
+all: bpf_jit_disasm bpf_dbg bpf_asm bpftool
 
 bpf_jit_disasm : CFLAGS += -DPACKAGE='bpf_jit_disasm'
 bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl
@@ -26,10 +27,21 @@ bpf_asm : LDLIBS =
 bpf_asm : bpf_asm.o bpf_exp.yacc.o bpf_exp.lex.o
 bpf_exp.lex.o : bpf_exp.yacc.c
 
-clean :
+clean: bpftool_clean
  rm -rf *.o bpf_jit_disasm bpf_dbg bpf_asm bpf_exp.yacc.* bpf_exp.lex.*
 
-install :
+install: bpftool_install
  install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm
  install bpf_dbg $(prefix)/bin/bpf_dbg
  install bpf_asm $(prefix)/bin/bpf_asm
+
+bpftool:
+ $(MAKE) -C bpftool
+
+bpftool_install:
+ $(MAKE) -C bpftool install
+
+bpftool_clean:
+ $(MAKE) -C bpftool clean
+
+.PHONY: bpftool FORCE

tools/bpf/bpftool/Makefile

@@ -0,0 +1,80 @@
+include ../../scripts/Makefile.include
+
+include ../../scripts/utilities.mak
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+ifneq ($(objtree),)
+#$(info Determined 'objtree' to be $(objtree))
+endif
+
+ifneq ($(OUTPUT),)
+#$(info Determined 'OUTPUT' to be $(OUTPUT))
+# Adding $(OUTPUT) as a directory to look for source files,
+# because use generated output files as sources dependency
+# for flex/bison parsers.
+VPATH += $(OUTPUT)
+export VPATH
+endif
+
+ifeq ($(V),1)
+ Q =
+else
+ Q = @
+endif
+
+BPF_DIR = $(srctree)/tools/lib/bpf/
+
+ifneq ($(OUTPUT),)
+ BPF_PATH=$(OUTPUT)
+else
+ BPF_PATH=$(BPF_DIR)
+endif
+
+LIBBPF = $(BPF_PATH)libbpf.a
+
+$(LIBBPF): FORCE
+ $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(OUTPUT) $(OUTPUT)libbpf.a FEATURES_DUMP=$(FEATURE_DUMP_EXPORT)
+
+$(LIBBPF)-clean:
+ $(call QUIET_CLEAN, libbpf)
+ $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(OUTPUT) clean >/dev/null
+
+prefix = /usr
+
+CC = gcc
+
+CFLAGS += -O2
+CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wshadow
+CFLAGS += -D__EXPORTED_HEADERS__ -I$(srctree)/tools/include/uapi -I$(srctree)/tools/include -I$(srctree)/tools/lib/bpf
+LIBS = -lelf -lbfd -lopcodes $(LIBBPF)
+
+include $(wildcard *.d)
+
+all: $(OUTPUT)bpftool
+
+SRCS=$(wildcard *.c)
+OBJS=$(patsubst %.c,$(OUTPUT)%.o,$(SRCS))
+
+$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
+ $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ $(LIBS)
+
+$(OUTPUT)%.o: %.c
+ $(QUIET_CC)$(COMPILE.c) -MMD -o $@ $<
+
+clean: $(LIBBPF)-clean
+ $(call QUIET_CLEAN, bpftool)
+ $(Q)rm -rf $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d
+
+install:
+ install $(OUTPUT)bpftool $(prefix)/sbin/bpftool
+
+FORCE:
+
+.PHONY: all clean FORCE
+.DEFAULT_GOAL := all

tools/bpf/bpftool/common.c

@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2017 Netronome Systems, Inc.
+ *
+ * This software is dual licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree or the BSD 2-Clause License provided below. You have the
+ * option to license this software under the complete terms of either license.
+ *
+ * The BSD 2-Clause License:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/* Author: Jakub Kicinski <[email protected]> */
+
+#include <errno.h>
+#include <libgen.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/limits.h>
+#include <linux/magic.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+
+#include <bpf.h>
+
+#include "main.h"
+
+static bool is_bpffs(char *path)
+{
+ struct statfs st_fs;
+
+ if (statfs(path, &st_fs) < 0)
+ return false;
+
+ return (unsigned long)st_fs.f_type == BPF_FS_MAGIC;
+}
+
+int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
+{
+ enum bpf_obj_type type;
+ int fd;
+
+ fd = bpf_obj_get(path);
+ if (fd < 0) {
+ err("bpf obj get (%s): %s\n", path,
+ errno == EACCES && !is_bpffs(dirname(path)) ?
+ "directory not in bpf file system (bpffs)" :
+ strerror(errno));
+ return -1;
+ }
+
+ type = get_fd_type(fd);
+ if (type < 0) {
+ close(fd);
+ return type;
+ }
+ if (type != exp_type) {
+ err("incorrect object type: %s\n", get_fd_type_name(type));
+ close(fd);
+ return -1;
+ }
+
+ return fd;
+}
+
+int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32))
+{
+ unsigned int id;
+ char *endptr;
+ int err;
+ int fd;
+
+ if (!is_prefix(*argv, "id")) {
+ err("expected 'id' got %s\n", *argv);
+ return -1;
+ }
+ NEXT_ARG();
+
+ id = strtoul(*argv, &endptr, 0);
+ if (*endptr) {
+ err("can't parse %s as ID\n", *argv);
+ return -1;
+ }
+ NEXT_ARG();
+
+ if (argc != 1)
+ usage();
+
+ fd = get_fd_by_id(id);
+ if (fd < 0) {
+ err("can't get prog by id (%u): %s\n", id, strerror(errno));
+ return -1;
+ }
+
+ err = bpf_obj_pin(fd, *argv);
+ close(fd);
+ if (err) {
+ err("can't pin the object (%s): %s\n", *argv,
+ errno == EACCES && !is_bpffs(dirname(*argv)) ?
+ "directory not in bpf file system (bpffs)" :
+ strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+const char *get_fd_type_name(enum bpf_obj_type type)
+{
+ static const char * const names[] = {
+ [BPF_OBJ_UNKNOWN] = "unknown",
+ [BPF_OBJ_PROG] = "prog",
+ [BPF_OBJ_MAP] = "map",
+ };
+
+ if (type < 0 || type >= ARRAY_SIZE(names) || !names[type])
+ return names[BPF_OBJ_UNKNOWN];
+
+ return names[type];
+}
+
+int get_fd_type(int fd)
+{
+ char path[PATH_MAX];
+ char buf[512];
+ ssize_t n;
+
+ snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd);
+
+ n = readlink(path, buf, sizeof(buf));
+ if (n < 0) {
+ err("can't read link type: %s\n", strerror(errno));
+ return -1;
+ }
+ if (n == sizeof(path)) {
+ err("can't read link type: path too long!\n");
+ return -1;
+ }
+
+ if (strstr(buf, "bpf-map"))
+ return BPF_OBJ_MAP;
+ else if (strstr(buf, "bpf-prog"))
+ return BPF_OBJ_PROG;
+
+ return BPF_OBJ_UNKNOWN;
+}
+
+char *get_fdinfo(int fd, const char *key)
+{
+ char path[PATH_MAX];
+ char *line = NULL;
+ size_t line_n = 0;
+ ssize_t n;
+ FILE *fdi;
+
+ snprintf(path, sizeof(path), "/proc/%d/fdinfo/%d", getpid(), fd);
+
+ fdi = fopen(path, "r");
+ if (!fdi) {
+ err("can't open fdinfo: %s\n", strerror(errno));
+ return NULL;
+ }
+
+ while ((n = getline(&line, &line_n, fdi))) {
+ char *value;
+ int len;
+
+ if (!strstr(line, key))
+ continue;
+
+ fclose(fdi);
+
+ value = strchr(line, '\t');
+ if (!value || !value[1]) {
+ err("malformed fdinfo!?\n");
+ free(line);
+ return NULL;
+ }
+ value++;
+
+ len = strlen(value);
+ memmove(line, value, len);
+ line[len - 1] = '\0';
+
+ return line;
+ }
+
+ err("key '%s' not found in fdinfo\n", key);
+ free(line);
+ fclose(fdi);
+ return NULL;
+}