03f4723ed7
this socket filter example does:
- creates arraymap in kernel with key 4 bytes and value 8 bytes
- loads eBPF program which assumes that packet is IPv4 and loads one byte of
IP->proto from the packet and uses it as a key in a map
r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)];
*(u32*)(fp - 4) = r0;
value = bpf_map_lookup_elem(map_fd, fp - 4);
if (value)
(*(u64*)value) += 1;
- attaches this program to raw socket
- every second user space reads map[IPPROTO_TCP], map[IPPROTO_UDP], map[IPPROTO_ICMP]
to see how many packets of given protocol were seen on loopback interface
Usage:
$sudo samples/bpf/sock_example
TCP 0 UDP 0 ICMP 0 packets
TCP 187600 UDP 0 ICMP 4 packets
TCP 376504 UDP 0 ICMP 8 packets
TCP 563116 UDP 0 ICMP 12 packets
TCP 753144 UDP 0 ICMP 16 packets
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
186 lines
4.8 KiB
C
186 lines
4.8 KiB
C
/* eBPF mini library */
|
|
#ifndef __LIBBPF_H
|
|
#define __LIBBPF_H
|
|
|
|
struct bpf_insn;
|
|
|
|
int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,
|
|
int max_entries);
|
|
int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags);
|
|
int bpf_lookup_elem(int fd, void *key, void *value);
|
|
int bpf_delete_elem(int fd, void *key);
|
|
int bpf_get_next_key(int fd, void *key, void *next_key);
|
|
|
|
int bpf_prog_load(enum bpf_prog_type prog_type,
|
|
const struct bpf_insn *insns, int insn_len,
|
|
const char *license);
|
|
|
|
#define LOG_BUF_SIZE 8192
|
|
extern char bpf_log_buf[LOG_BUF_SIZE];
|
|
|
|
/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
|
|
|
|
#define BPF_ALU64_REG(OP, DST, SRC) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = 0, \
|
|
.imm = 0 })
|
|
|
|
#define BPF_ALU32_REG(OP, DST, SRC) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU | BPF_OP(OP) | BPF_X, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = 0, \
|
|
.imm = 0 })
|
|
|
|
/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
|
|
|
|
#define BPF_ALU64_IMM(OP, DST, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
|
|
.dst_reg = DST, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = IMM })
|
|
|
|
#define BPF_ALU32_IMM(OP, DST, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU | BPF_OP(OP) | BPF_K, \
|
|
.dst_reg = DST, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = IMM })
|
|
|
|
/* Short form of mov, dst_reg = src_reg */
|
|
|
|
#define BPF_MOV64_REG(DST, SRC) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU64 | BPF_MOV | BPF_X, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = 0, \
|
|
.imm = 0 })
|
|
|
|
/* Short form of mov, dst_reg = imm32 */
|
|
|
|
#define BPF_MOV64_IMM(DST, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ALU64 | BPF_MOV | BPF_K, \
|
|
.dst_reg = DST, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = IMM })
|
|
|
|
/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
|
|
#define BPF_LD_IMM64(DST, IMM) \
|
|
BPF_LD_IMM64_RAW(DST, 0, IMM)
|
|
|
|
#define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_LD | BPF_DW | BPF_IMM, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = 0, \
|
|
.imm = (__u32) (IMM) }), \
|
|
((struct bpf_insn) { \
|
|
.code = 0, /* zero is reserved opcode */ \
|
|
.dst_reg = 0, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = ((__u64) (IMM)) >> 32 })
|
|
|
|
#define BPF_PSEUDO_MAP_FD 1
|
|
|
|
/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
|
|
#define BPF_LD_MAP_FD(DST, MAP_FD) \
|
|
BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
|
|
|
|
|
|
/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
|
|
|
|
#define BPF_LD_ABS(SIZE, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
|
|
.dst_reg = 0, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = IMM })
|
|
|
|
/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
|
|
|
|
#define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = OFF, \
|
|
.imm = 0 })
|
|
|
|
/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
|
|
|
|
#define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = OFF, \
|
|
.imm = 0 })
|
|
|
|
/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
|
|
|
|
#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
|
|
.dst_reg = DST, \
|
|
.src_reg = 0, \
|
|
.off = OFF, \
|
|
.imm = IMM })
|
|
|
|
/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
|
|
|
|
#define BPF_JMP_REG(OP, DST, SRC, OFF) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_JMP | BPF_OP(OP) | BPF_X, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = OFF, \
|
|
.imm = 0 })
|
|
|
|
/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
|
|
|
|
#define BPF_JMP_IMM(OP, DST, IMM, OFF) \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_JMP | BPF_OP(OP) | BPF_K, \
|
|
.dst_reg = DST, \
|
|
.src_reg = 0, \
|
|
.off = OFF, \
|
|
.imm = IMM })
|
|
|
|
/* Raw code statement block */
|
|
|
|
#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
|
|
((struct bpf_insn) { \
|
|
.code = CODE, \
|
|
.dst_reg = DST, \
|
|
.src_reg = SRC, \
|
|
.off = OFF, \
|
|
.imm = IMM })
|
|
|
|
/* Program exit */
|
|
|
|
#define BPF_EXIT_INSN() \
|
|
((struct bpf_insn) { \
|
|
.code = BPF_JMP | BPF_EXIT, \
|
|
.dst_reg = 0, \
|
|
.src_reg = 0, \
|
|
.off = 0, \
|
|
.imm = 0 })
|
|
|
|
/* create RAW socket and bind to interface 'name' */
|
|
int open_raw_sock(const char *name);
|
|
|
|
#endif
|