From 42984d7c1e563bf92e6ca7a0fd89f8e933f2162e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 29 Oct 2015 14:58:10 +0100 Subject: [PATCH] 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 Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/Makefile | 3 + samples/bpf/fds_example.c | 183 ++++++++++++++++++++++++++++++++++++++ samples/bpf/libbpf.c | 19 ++++ samples/bpf/libbpf.h | 3 + 4 files changed, 208 insertions(+) create mode 100644 samples/bpf/fds_example.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index b30514514e37..79b4596b5f9a 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -4,6 +4,7 @@ obj- := dummy.o # List of programs to build hostprogs-y := test_verifier test_maps hostprogs-y += sock_example +hostprogs-y += fds_example hostprogs-y += sockex1 hostprogs-y += sockex2 hostprogs-y += sockex3 @@ -19,6 +20,7 @@ hostprogs-y += lathist test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o sock_example-objs := sock_example.o libbpf.o +fds_example-objs := bpf_load.o libbpf.o fds_example.o sockex1-objs := bpf_load.o libbpf.o sockex1_user.o sockex2-objs := bpf_load.o libbpf.o sockex2_user.o sockex3-objs := bpf_load.o libbpf.o sockex3_user.o @@ -49,6 +51,7 @@ always += lathist_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable +HOSTLOADLIBES_fds_example += -lelf HOSTLOADLIBES_sockex1 += -lelf HOSTLOADLIBES_sockex2 += -lelf HOSTLOADLIBES_sockex3 += -lelf diff --git a/samples/bpf/fds_example.c b/samples/bpf/fds_example.c new file mode 100644 index 000000000000..e2fd16c3d0f0 --- /dev/null +++ b/samples/bpf/fds_example.c @@ -0,0 +1,183 @@ +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "bpf_load.h" +#include "libbpf.h" + +#define BPF_F_PIN (1 << 0) +#define BPF_F_GET (1 << 1) +#define BPF_F_PIN_GET (BPF_F_PIN | BPF_F_GET) + +#define BPF_F_KEY (1 << 2) +#define BPF_F_VAL (1 << 3) +#define BPF_F_KEY_VAL (BPF_F_KEY | BPF_F_VAL) + +#define BPF_M_UNSPEC 0 +#define BPF_M_MAP 1 +#define BPF_M_PROG 2 + +static void usage(void) +{ + printf("Usage: fds_example [...]\n"); + printf(" -F File to pin/get object\n"); + printf(" -P |- pin object\n"); + printf(" -G `- get object\n"); + printf(" -m eBPF map mode\n"); + printf(" -k |- map key\n"); + printf(" -v `- map value\n"); + printf(" -p eBPF prog mode\n"); + printf(" -o `- object file\n"); + printf(" -h Display this help.\n"); +} + +static int bpf_map_create(void) +{ + return bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(uint32_t), + sizeof(uint32_t), 1024); +} + +static int bpf_prog_create(const char *object) +{ + static const struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }; + + if (object) { + assert(!load_bpf_file((char *)object)); + return prog_fd[0]; + } else { + return bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, + insns, sizeof(insns), "GPL", 0); + } +} + +static int bpf_do_map(const char *file, uint32_t flags, uint32_t key, + uint32_t value) +{ + int fd, ret; + + if (flags & BPF_F_PIN) { + fd = bpf_map_create(); + printf("bpf: map fd:%d (%s)\n", fd, strerror(errno)); + assert(fd > 0); + + ret = bpf_obj_pin(fd, file); + printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno)); + assert(ret == 0); + } else { + fd = bpf_obj_get(file); + printf("bpf: get fd:%d (%s)\n", fd, strerror(errno)); + assert(fd > 0); + } + + if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) { + ret = bpf_update_elem(fd, &key, &value, 0); + printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value, + ret, strerror(errno)); + assert(ret == 0); + } else if (flags & BPF_F_KEY) { + ret = bpf_lookup_elem(fd, &key, &value); + printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value, + ret, strerror(errno)); + assert(ret == 0); + } + + return 0; +} + +static int bpf_do_prog(const char *file, uint32_t flags, const char *object) +{ + int fd, sock, ret; + + if (flags & BPF_F_PIN) { + fd = bpf_prog_create(object); + printf("bpf: prog fd:%d (%s)\n", fd, strerror(errno)); + assert(fd > 0); + + ret = bpf_obj_pin(fd, file); + printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno)); + assert(ret == 0); + } else { + fd = bpf_obj_get(file); + printf("bpf: get fd:%d (%s)\n", fd, strerror(errno)); + assert(fd > 0); + } + + sock = open_raw_sock("lo"); + assert(sock > 0); + + ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &fd, sizeof(fd)); + printf("bpf: sock:%d <- fd:%d attached ret:(%d,%s)\n", sock, fd, + ret, strerror(errno)); + assert(ret == 0); + + return 0; +} + +int main(int argc, char **argv) +{ + const char *file = NULL, *object = NULL; + uint32_t key = 0, value = 0, flags = 0; + int opt, mode = BPF_M_UNSPEC; + + while ((opt = getopt(argc, argv, "F:PGmk:v:po:")) != -1) { + switch (opt) { + /* General args */ + case 'F': + file = optarg; + break; + case 'P': + flags |= BPF_F_PIN; + break; + case 'G': + flags |= BPF_F_GET; + break; + /* Map-related args */ + case 'm': + mode = BPF_M_MAP; + break; + case 'k': + key = strtoul(optarg, NULL, 0); + flags |= BPF_F_KEY; + break; + case 'v': + value = strtoul(optarg, NULL, 0); + flags |= BPF_F_VAL; + break; + /* Prog-related args */ + case 'p': + mode = BPF_M_PROG; + break; + case 'o': + object = optarg; + break; + default: + goto out; + } + } + + if (!(flags & BPF_F_PIN_GET) || !file) + goto out; + + switch (mode) { + case BPF_M_MAP: + return bpf_do_map(file, flags, key, value); + case BPF_M_PROG: + return bpf_do_prog(file, flags, object); + } +out: + usage(); + return -1; +} diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c index 7e1efa7e2ed7..65a8d48d2799 100644 --- a/samples/bpf/libbpf.c +++ b/samples/bpf/libbpf.c @@ -103,6 +103,25 @@ int bpf_prog_load(enum bpf_prog_type prog_type, return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr)); } +int bpf_obj_pin(int fd, const char *pathname) +{ + union bpf_attr attr = { + .pathname = ptr_to_u64((void *)pathname), + .bpf_fd = fd, + }; + + return syscall(__NR_bpf, BPF_OBJ_PIN, &attr, sizeof(attr)); +} + +int bpf_obj_get(const char *pathname) +{ + union bpf_attr attr = { + .pathname = ptr_to_u64((void *)pathname), + }; + + return syscall(__NR_bpf, BPF_OBJ_GET, &attr, sizeof(attr)); +} + int open_raw_sock(const char *name) { struct sockaddr_ll sll; diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h index b7f63c70b4a2..014aacf916e4 100644 --- a/samples/bpf/libbpf.h +++ b/samples/bpf/libbpf.h @@ -15,6 +15,9 @@ int bpf_prog_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, int insn_len, const char *license, int kern_version); +int bpf_obj_pin(int fd, const char *pathname); +int bpf_obj_get(const char *pathname); + #define LOG_BUF_SIZE 65536 extern char bpf_log_buf[LOG_BUF_SIZE]; -- GitLab