bpf: add sample usages for persistent maps/progs
This patch adds a couple of stand-alone examples on how BPF_OBJ_PIN and BPF_OBJ_GET commands can be used. Example with maps: # ./fds_example -F /sys/fs/bpf/m -P -m -k 1 -v 42 bpf: map fd:3 (Success) bpf: pin ret:(0,Success) bpf: fd:3 u->(1:42) ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m -G -m -k 1 bpf: get fd:3 (Success) bpf: fd:3 l->(1):42 ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m -G -m -k 1 -v 24 bpf: get fd:3 (Success) bpf: fd:3 u->(1:24) ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m -G -m -k 1 bpf: get fd:3 (Success) bpf: fd:3 l->(1):24 ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m2 -P -m bpf: map fd:3 (Success) bpf: pin ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m2 -G -m -k 1 bpf: get fd:3 (Success) bpf: fd:3 l->(1):0 ret:(0,Success) # ./fds_example -F /sys/fs/bpf/m2 -G -m bpf: get fd:3 (Success) Example with progs: # ./fds_example -F /sys/fs/bpf/p -P -p bpf: prog fd:3 (Success) bpf: pin ret:(0,Success) bpf sock:4 <- fd:3 attached ret:(0,Success) # ./fds_example -F /sys/fs/bpf/p -G -p bpf: get fd:3 (Success) bpf: sock:4 <- fd:3 attached ret:(0,Success) # ./fds_example -F /sys/fs/bpf/p2 -P -p -o ./sockex1_kern.o bpf: prog fd:5 (Success) bpf: pin ret:(0,Success) bpf: sock:3 <- fd:5 attached ret:(0,Success) # ./fds_example -F /sys/fs/bpf/p2 -G -p bpf: get fd:3 (Success) bpf: sock:4 <- fd:3 attached ret:(0,Success) Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Родитель
b2197755b2
Коммит
42984d7c1e
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@ -4,6 +4,7 @@ obj- := dummy.o
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# List of programs to build
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hostprogs-y := test_verifier test_maps
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hostprogs-y += sock_example
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hostprogs-y += fds_example
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hostprogs-y += sockex1
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hostprogs-y += sockex2
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hostprogs-y += sockex3
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@ -19,6 +20,7 @@ hostprogs-y += lathist
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test_verifier-objs := test_verifier.o libbpf.o
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test_maps-objs := test_maps.o libbpf.o
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sock_example-objs := sock_example.o libbpf.o
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fds_example-objs := bpf_load.o libbpf.o fds_example.o
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sockex1-objs := bpf_load.o libbpf.o sockex1_user.o
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sockex2-objs := bpf_load.o libbpf.o sockex2_user.o
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sockex3-objs := bpf_load.o libbpf.o sockex3_user.o
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@ -49,6 +51,7 @@ always += lathist_kern.o
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HOSTCFLAGS += -I$(objtree)/usr/include
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HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
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HOSTLOADLIBES_fds_example += -lelf
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HOSTLOADLIBES_sockex1 += -lelf
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HOSTLOADLIBES_sockex2 += -lelf
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HOSTLOADLIBES_sockex3 += -lelf
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@ -0,0 +1,183 @@
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#include <linux/unistd.h>
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#include <linux/bpf.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include "bpf_load.h"
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#include "libbpf.h"
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#define BPF_F_PIN (1 << 0)
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#define BPF_F_GET (1 << 1)
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#define BPF_F_PIN_GET (BPF_F_PIN | BPF_F_GET)
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#define BPF_F_KEY (1 << 2)
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#define BPF_F_VAL (1 << 3)
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#define BPF_F_KEY_VAL (BPF_F_KEY | BPF_F_VAL)
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#define BPF_M_UNSPEC 0
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#define BPF_M_MAP 1
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#define BPF_M_PROG 2
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static void usage(void)
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{
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printf("Usage: fds_example [...]\n");
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printf(" -F <file> File to pin/get object\n");
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printf(" -P |- pin object\n");
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printf(" -G `- get object\n");
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printf(" -m eBPF map mode\n");
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printf(" -k <key> |- map key\n");
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printf(" -v <value> `- map value\n");
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printf(" -p eBPF prog mode\n");
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printf(" -o <object> `- object file\n");
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printf(" -h Display this help.\n");
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}
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static int bpf_map_create(void)
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{
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return bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(uint32_t),
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sizeof(uint32_t), 1024);
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}
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static int bpf_prog_create(const char *object)
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{
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static const struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 1),
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BPF_EXIT_INSN(),
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};
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if (object) {
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assert(!load_bpf_file((char *)object));
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return prog_fd[0];
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} else {
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return bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER,
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insns, sizeof(insns), "GPL", 0);
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}
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}
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static int bpf_do_map(const char *file, uint32_t flags, uint32_t key,
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uint32_t value)
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{
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int fd, ret;
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if (flags & BPF_F_PIN) {
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fd = bpf_map_create();
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printf("bpf: map fd:%d (%s)\n", fd, strerror(errno));
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assert(fd > 0);
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ret = bpf_obj_pin(fd, file);
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printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
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assert(ret == 0);
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} else {
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fd = bpf_obj_get(file);
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printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
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assert(fd > 0);
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}
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if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) {
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ret = bpf_update_elem(fd, &key, &value, 0);
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printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value,
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ret, strerror(errno));
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assert(ret == 0);
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} else if (flags & BPF_F_KEY) {
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ret = bpf_lookup_elem(fd, &key, &value);
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printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value,
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ret, strerror(errno));
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assert(ret == 0);
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}
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return 0;
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}
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static int bpf_do_prog(const char *file, uint32_t flags, const char *object)
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{
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int fd, sock, ret;
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if (flags & BPF_F_PIN) {
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fd = bpf_prog_create(object);
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printf("bpf: prog fd:%d (%s)\n", fd, strerror(errno));
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assert(fd > 0);
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ret = bpf_obj_pin(fd, file);
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printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
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assert(ret == 0);
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} else {
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fd = bpf_obj_get(file);
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printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
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assert(fd > 0);
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}
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sock = open_raw_sock("lo");
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assert(sock > 0);
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ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &fd, sizeof(fd));
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printf("bpf: sock:%d <- fd:%d attached ret:(%d,%s)\n", sock, fd,
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ret, strerror(errno));
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assert(ret == 0);
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return 0;
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}
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int main(int argc, char **argv)
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{
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const char *file = NULL, *object = NULL;
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uint32_t key = 0, value = 0, flags = 0;
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int opt, mode = BPF_M_UNSPEC;
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while ((opt = getopt(argc, argv, "F:PGmk:v:po:")) != -1) {
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switch (opt) {
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/* General args */
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case 'F':
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file = optarg;
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break;
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case 'P':
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flags |= BPF_F_PIN;
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break;
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case 'G':
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flags |= BPF_F_GET;
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break;
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/* Map-related args */
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case 'm':
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mode = BPF_M_MAP;
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break;
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case 'k':
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key = strtoul(optarg, NULL, 0);
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flags |= BPF_F_KEY;
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break;
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case 'v':
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value = strtoul(optarg, NULL, 0);
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flags |= BPF_F_VAL;
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break;
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/* Prog-related args */
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case 'p':
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mode = BPF_M_PROG;
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break;
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case 'o':
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object = optarg;
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break;
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default:
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goto out;
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}
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}
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if (!(flags & BPF_F_PIN_GET) || !file)
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goto out;
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switch (mode) {
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case BPF_M_MAP:
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return bpf_do_map(file, flags, key, value);
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case BPF_M_PROG:
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return bpf_do_prog(file, flags, object);
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}
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out:
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usage();
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return -1;
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}
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@ -103,6 +103,25 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
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return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
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}
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int bpf_obj_pin(int fd, const char *pathname)
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{
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union bpf_attr attr = {
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.pathname = ptr_to_u64((void *)pathname),
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.bpf_fd = fd,
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};
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return syscall(__NR_bpf, BPF_OBJ_PIN, &attr, sizeof(attr));
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}
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int bpf_obj_get(const char *pathname)
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{
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union bpf_attr attr = {
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.pathname = ptr_to_u64((void *)pathname),
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};
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return syscall(__NR_bpf, BPF_OBJ_GET, &attr, sizeof(attr));
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}
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int open_raw_sock(const char *name)
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{
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struct sockaddr_ll sll;
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@ -15,6 +15,9 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
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const struct bpf_insn *insns, int insn_len,
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const char *license, int kern_version);
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int bpf_obj_pin(int fd, const char *pathname);
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int bpf_obj_get(const char *pathname);
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#define LOG_BUF_SIZE 65536
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extern char bpf_log_buf[LOG_BUF_SIZE];
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